1 00:00:10,459 --> 00:00:06,320 alright it's 8 o'clock and we have a 2 00:00:11,900 --> 00:00:10,469 nicely busy house so we'll start as I 3 00:00:15,440 --> 00:00:11,910 said my name is Alex Lockwood I'm 4 00:00:18,130 --> 00:00:15,450 replacing Frank summers this evening not 5 00:00:23,090 --> 00:00:18,140 replacing trying to emulate his 6 00:00:24,620 --> 00:00:23,100 magnificence and I'm just here to host 7 00:00:28,040 --> 00:00:24,630 your evening the real star of the show 8 00:00:30,859 --> 00:00:28,050 is dr. Ashley just a couple of 9 00:00:33,260 --> 00:00:30,869 announcements as I mentioned if you're 10 00:00:35,060 --> 00:00:33,270 interested in going to across the street 11 00:00:37,400 --> 00:00:35,070 to the johns hopkins observatory and 12 00:00:38,780 --> 00:00:37,410 looking through their telescope please 13 00:00:42,440 --> 00:00:38,790 meet after the talk 14 00:00:45,080 --> 00:00:42,450 up here at the podium we have a couple 15 00:00:47,270 --> 00:00:45,090 of upcoming public lecture series the 16 00:00:49,970 --> 00:00:47,280 public lecture series for September is 17 00:00:53,180 --> 00:00:49,980 on September 3rd the topic is the 18 00:00:55,400 --> 00:00:53,190 astronomers toolkit and the speaker is 19 00:01:01,549 --> 00:00:55,410 another outreach scientist named dr. 20 00:01:04,399 --> 00:01:01,559 Brandon Lawton yeah Brandon and then on 21 00:01:07,250 --> 00:01:04,409 October the October public lecture is on 22 00:01:10,160 --> 00:01:07,260 October 1st and the title is black holes 23 00:01:13,370 --> 00:01:10,170 and gravitational waves which is very 24 00:01:16,070 --> 00:01:13,380 cool and the speaker is from Johns 25 00:01:18,440 --> 00:01:16,080 Hopkins his name is Emanuel Liberty 26 00:01:19,700 --> 00:01:18,450 I may have butchered that but those are 27 00:01:22,370 --> 00:01:19,710 the upcoming talks they're also 28 00:01:27,050 --> 00:01:22,380 available online as is this recording 29 00:01:30,200 --> 00:01:27,060 after after tonight so with that I would 30 00:01:32,210 --> 00:01:30,210 like to introduce tonight's speaker dr. 31 00:01:34,880 --> 00:01:32,220 Tricia Ashley got her bachelor's degree 32 00:01:38,300 --> 00:01:34,890 in physics and astronomy from the Bryn 33 00:01:40,399 --> 00:01:38,310 Mawr College in 2008 in 2014 she 34 00:01:43,010 --> 00:01:40,409 received her PhD in physics from Florida 35 00:01:45,170 --> 00:01:43,020 International University for her PhD 36 00:01:48,440 --> 00:01:45,180 dissertation she studied star formation 37 00:01:52,160 --> 00:01:48,450 in blue compact dwarf galaxies as part 38 00:01:53,630 --> 00:01:52,170 of the research team little things she 39 00:01:55,789 --> 00:01:53,640 has since worked on understanding the 40 00:01:58,550 --> 00:01:55,799 gas content in isolated early type 41 00:02:00,499 --> 00:01:58,560 galaxies as a postdoc at NASA Ames and 42 00:02:01,870 --> 00:02:00,509 she's currently working as a postdoc at 43 00:02:06,139 --> 00:02:01,880 the Space Telescope Science Institute 44 00:02:07,999 --> 00:02:06,149 with Andy Fox here at Space Telescope's 45 00:02:10,700 --> 00:02:08,009 she studies the Fermi bubbles and gas 46 00:02:13,370 --> 00:02:10,710 flows into and from 47 00:02:15,920 --> 00:02:13,380 the Milky Way she also spends time as an 48 00:02:17,390 --> 00:02:15,930 organiser of astronomy on tap Baltimore 49 00:02:19,700 --> 00:02:17,400 which I'm sure she'd be happy to answer 50 00:02:21,860 --> 00:02:19,710 questions about an outreach program that 51 00:02:23,870 --> 00:02:21,870 brings scientists to bars in Baltimore 52 00:02:26,600 --> 00:02:23,880 to give fun and exciting talks about 53 00:02:36,740 --> 00:02:26,610 space so please join me in a round of 54 00:02:39,680 --> 00:02:36,750 applause welcome dr. Ashley okay can you 55 00:02:42,320 --> 00:02:39,690 hear me good okay that was a great 56 00:02:44,210 --> 00:02:42,330 introduction to my talk because it 57 00:02:47,180 --> 00:02:44,220 actually now I can stick a few lines my 58 00:02:50,810 --> 00:02:47,190 talk so today I'm going to talk to you 59 00:02:53,240 --> 00:02:50,820 about dwarf galaxies but first as 60 00:02:55,340 --> 00:02:53,250 mentioned earlier I actually wanted to 61 00:02:57,050 --> 00:02:55,350 tell you where I got my passion for 62 00:03:00,170 --> 00:02:57,060 dwarf galaxies and that was during my 63 00:03:03,160 --> 00:03:00,180 dissertation because as mentioned I did 64 00:03:05,750 --> 00:03:03,170 my dissertation work on dwarf galaxies 65 00:03:08,300 --> 00:03:05,760 so this is a picture of me getting my 66 00:03:12,530 --> 00:03:08,310 PhD this is one of my official photos 67 00:03:14,240 --> 00:03:12,540 yes very nice and so I got my PhD 68 00:03:16,130 --> 00:03:14,250 because I did that work on dwarf 69 00:03:18,410 --> 00:03:16,140 galaxies but I want to take a minute to 70 00:03:26,600 --> 00:03:18,420 analyze this photo because I'm a 71 00:03:29,840 --> 00:03:26,610 scientist no but very close so this 72 00:03:33,680 --> 00:03:29,850 picture I really believe is a graduation 73 00:03:36,770 --> 00:03:33,690 photo level expert and the reason I 74 00:03:41,449 --> 00:03:36,780 believe that is because one you got your 75 00:03:42,800 --> 00:03:41,459 monocle - you have your pipe three most 76 00:03:44,840 --> 00:03:42,810 of you may have missed it but you have 77 00:03:48,260 --> 00:03:44,850 your flask strapped to your leg filled 78 00:03:49,940 --> 00:03:48,270 with coffee of course and then finally 79 00:03:53,840 --> 00:03:49,950 you have your family degree because of 80 00:03:55,729 --> 00:03:53,850 real things in the mail so as mentioned 81 00:03:57,440 --> 00:03:55,739 I got my PhD on this work and I've been 82 00:03:59,990 --> 00:03:57,450 interested in it ever since and I 83 00:04:02,720 --> 00:04:00,000 continue to work on it on the side but 84 00:04:04,550 --> 00:04:02,730 before I introduced to George Gallup see 85 00:04:07,520 --> 00:04:04,560 I want to first introduce to you your 86 00:04:10,370 --> 00:04:07,530 own galaxy that you live in and that is 87 00:04:14,150 --> 00:04:10,380 the Milky Way so this is a beautiful 88 00:04:17,960 --> 00:04:14,160 picture taken of the night sky and if 89 00:04:20,150 --> 00:04:17,970 you go out into a very dark place where 90 00:04:22,790 --> 00:04:20,160 the nearest city is tens of miles away 91 00:04:24,020 --> 00:04:22,800 and look up at the sky you might see 92 00:04:26,210 --> 00:04:24,030 something like this 93 00:04:28,820 --> 00:04:26,220 now it won't be this beautiful in color 94 00:04:31,460 --> 00:04:28,830 it'll be mostly gray and white but it's 95 00:04:34,010 --> 00:04:31,470 the same idea we're going down the 96 00:04:37,100 --> 00:04:34,020 middle of this image you have the Milky 97 00:04:39,560 --> 00:04:37,110 Way disk so this is a galaxy that you 98 00:04:41,540 --> 00:04:39,570 all live in and you can see it 99 00:04:45,320 --> 00:04:41,550 yourselves if you do go out to these 100 00:04:47,210 --> 00:04:45,330 very dark sky places now if you take a 101 00:04:48,020 --> 00:04:47,220 bunch of images of the Milky Way from 102 00:04:49,760 --> 00:04:48,030 Earth 103 00:04:52,910 --> 00:04:49,770 and put them together you can get an 104 00:04:57,350 --> 00:04:52,920 image like this where most of the light 105 00:04:59,570 --> 00:04:57,360 is in this thin disc here and that's the 106 00:05:03,080 --> 00:04:59,580 disc the main disk of our galaxy the 107 00:05:06,409 --> 00:05:03,090 Milky Way so it's very thin and most of 108 00:05:10,340 --> 00:05:06,419 that light is coming from stars in our 109 00:05:13,940 --> 00:05:10,350 galaxy and so our galaxy is made up of 110 00:05:16,040 --> 00:05:13,950 stars dust gas and dark matter all of 111 00:05:19,430 --> 00:05:16,050 those things put together and it's this 112 00:05:21,710 --> 00:05:19,440 little island of all of those things so 113 00:05:27,650 --> 00:05:21,720 that's why I called dwarf galaxies 114 00:05:32,030 --> 00:05:27,660 islands of stars now it looks very thin 115 00:05:34,700 --> 00:05:32,040 in this picture oops blah we'll go back 116 00:05:38,810 --> 00:05:34,710 well then there it is it looks very thin 117 00:05:41,750 --> 00:05:38,820 in this picture that's because the main 118 00:05:44,659 --> 00:05:41,760 disk of our galaxy is quite thin but 119 00:05:46,550 --> 00:05:44,669 that's only our view from the earth what 120 00:05:50,210 --> 00:05:46,560 does it look like when we leave the 121 00:05:52,370 --> 00:05:50,220 earth and leave the galaxy and look back 122 00:05:53,840 --> 00:05:52,380 at it well we can't actually do that 123 00:05:57,170 --> 00:05:53,850 because we don't have the technology to 124 00:05:59,900 --> 00:05:57,180 go that fast but with the data that 125 00:06:01,490 --> 00:05:59,910 we've collected from the Milky Way we 126 00:06:03,890 --> 00:06:01,500 can actually have an artist put together 127 00:06:07,520 --> 00:06:03,900 a picture of what we think it looks like 128 00:06:11,000 --> 00:06:07,530 if we were to leave the galaxy and go 129 00:06:13,550 --> 00:06:11,010 look at it from above so this is what we 130 00:06:16,580 --> 00:06:13,560 think it might look like where you're 131 00:06:18,170 --> 00:06:16,590 here half about halfway between the 132 00:06:20,960 --> 00:06:18,180 center of the galaxy in the outer edge 133 00:06:22,430 --> 00:06:20,970 and we do want to be there we don't want 134 00:06:24,020 --> 00:06:22,440 to be too close to the center because 135 00:06:26,590 --> 00:06:24,030 too much is going on there it would be 136 00:06:31,070 --> 00:06:26,600 very disastrous for us as a population 137 00:06:32,600 --> 00:06:31,080 but you have a couple of features here 138 00:06:35,510 --> 00:06:32,610 that I'd like to point out one it's not 139 00:06:37,010 --> 00:06:35,520 thin anymore if we look down at it it's 140 00:06:39,920 --> 00:06:37,020 this big round dish 141 00:06:42,380 --> 00:06:39,930 so you can think of our galaxy as like a 142 00:06:44,090 --> 00:06:42,390 thin plate it's not exactly shaped 143 00:06:46,790 --> 00:06:44,100 exactly like a plate but it's pretty 144 00:06:49,280 --> 00:06:46,800 much like one and then on top of that 145 00:06:52,340 --> 00:06:49,290 you have these big beautiful spiraling 146 00:06:54,680 --> 00:06:52,350 arms so astronomers look at galaxies 147 00:06:56,360 --> 00:06:54,690 like this and they say oh it has 148 00:06:58,220 --> 00:06:56,370 spiraling arms so we'll call that a 149 00:07:01,340 --> 00:06:58,230 spiral galaxy because we're really good 150 00:07:04,970 --> 00:07:01,350 at naming things so we live in a spiral 151 00:07:08,210 --> 00:07:04,980 galaxy which is great and we have a 152 00:07:10,280 --> 00:07:08,220 pretty good understanding of our no own 153 00:07:11,990 --> 00:07:10,290 Milky Way for having lived in it we're 154 00:07:13,550 --> 00:07:12,000 not we don't understand everything but 155 00:07:16,220 --> 00:07:13,560 we're still studying a lot about it but 156 00:07:18,620 --> 00:07:16,230 one thing we do know is that we are not 157 00:07:21,620 --> 00:07:18,630 the only galaxies out there there are 158 00:07:24,170 --> 00:07:21,630 lots of other galaxies and to prove this 159 00:07:26,300 --> 00:07:24,180 point I have this beautiful image here 160 00:07:27,980 --> 00:07:26,310 which is the Hubble Deep Field so this 161 00:07:30,860 --> 00:07:27,990 is a very famous image and I'm gonna 162 00:07:32,810 --> 00:07:30,870 explain why what they did was a bunch of 163 00:07:36,440 --> 00:07:32,820 astronomers in the 1990s got together 164 00:07:38,330 --> 00:07:36,450 and they said hey what would happen if 165 00:07:40,490 --> 00:07:38,340 we take the Hubble Space Telescope our 166 00:07:43,250 --> 00:07:40,500 most powerful optical telescope and 167 00:07:46,400 --> 00:07:43,260 point it at a black part of this guy 168 00:07:48,380 --> 00:07:46,410 like we don't see anything there nothing 169 00:07:51,020 --> 00:07:48,390 what would happen if we just point it 170 00:07:52,550 --> 00:07:51,030 there for a really long time and so a 171 00:07:54,830 --> 00:07:52,560 bunch of other astronomers who had to 172 00:07:57,830 --> 00:07:54,840 approve this plan said yeah why not go 173 00:08:00,380 --> 00:07:57,840 for it so they spent 10 days in over a 174 00:08:02,560 --> 00:08:00,390 hundred hours staring at this part of 175 00:08:05,960 --> 00:08:02,570 the sky that was supposed to be empty 176 00:08:09,710 --> 00:08:05,970 very small part of this guy yes correct 177 00:08:11,840 --> 00:08:09,720 and they got this and this is a 178 00:08:13,850 --> 00:08:11,850 beautiful image because aside from a few 179 00:08:16,700 --> 00:08:13,860 stars which you can tell have these 180 00:08:18,620 --> 00:08:16,710 pointy features here so those are stars 181 00:08:20,150 --> 00:08:18,630 in our own galaxy the Milky Way we can't 182 00:08:22,000 --> 00:08:20,160 go out there and tell them to move so we 183 00:08:26,080 --> 00:08:22,010 just have to leave them in the image 184 00:08:29,420 --> 00:08:26,090 everything in this image is a galaxy 185 00:08:32,380 --> 00:08:29,430 there are almost 3000 galaxies in this 186 00:08:34,640 --> 00:08:32,390 image and as you can tell from it 187 00:08:37,130 --> 00:08:34,650 they're all different colors and 188 00:08:39,740 --> 00:08:37,140 different shapes so there are lots of 189 00:08:41,690 --> 00:08:39,750 types of galaxies out there and we are 190 00:08:44,150 --> 00:08:41,700 definitely not the only galaxies so lots 191 00:08:48,530 --> 00:08:44,160 of little islands of stars dust gas and 192 00:08:50,060 --> 00:08:48,540 dark matter so I haven't talked much 193 00:08:50,480 --> 00:08:50,070 about dwarf galaxies yet 194 00:08:52,639 --> 00:08:50,490 let's do 195 00:08:54,740 --> 00:08:52,649 that so this again is the artist 196 00:08:56,660 --> 00:08:54,750 depiction of our own Milky Way and what 197 00:08:58,610 --> 00:08:56,670 we think it looks like what happens if 198 00:09:02,690 --> 00:08:58,620 we put outdoors galaxies next to it 199 00:09:04,420 --> 00:09:02,700 Oh looks approximately like that tiny 200 00:09:08,750 --> 00:09:04,430 little square up there in the top left 201 00:09:13,670 --> 00:09:08,760 so it's quite small dwarf galaxies are 202 00:09:15,680 --> 00:09:13,680 about 1/10 - down to about 125th the 203 00:09:18,920 --> 00:09:15,690 size of a big spiral galaxy like our 204 00:09:21,320 --> 00:09:18,930 Milky Way so they're very small so the 205 00:09:23,630 --> 00:09:21,330 question becomes why do we care about 206 00:09:27,800 --> 00:09:23,640 such tiny galaxies what's the point of 207 00:09:30,639 --> 00:09:27,810 studying them well first off there are a 208 00:09:33,019 --> 00:09:30,649 lot of them nearby us and so this image 209 00:09:34,820 --> 00:09:33,029 even though a little bit hard to read it 210 00:09:37,550 --> 00:09:34,830 proves a-- where we have the Milky Way 211 00:09:39,410 --> 00:09:37,560 in the center labeled in yellow and then 212 00:09:41,120 --> 00:09:39,420 we have these two yellow labels here 213 00:09:44,329 --> 00:09:41,130 which are the Andromeda galaxy in the 214 00:09:48,500 --> 00:09:44,339 Triangulum galaxy so those galaxies in 215 00:09:51,139 --> 00:09:48,510 yellow are nearest massive neighbors so 216 00:09:54,350 --> 00:09:51,149 they're big galaxies everything else 217 00:09:57,920 --> 00:09:54,360 here is labeled in light blue and those 218 00:10:00,860 --> 00:09:57,930 are all dwarf galaxies there are about 219 00:10:03,710 --> 00:10:00,870 last time I checked for tea or fuel 220 00:10:06,019 --> 00:10:03,720 exceeds with a distance to the Milky Way 221 00:10:10,550 --> 00:10:06,029 that is smaller than our distance to 222 00:10:12,980 --> 00:10:10,560 Andromeda so 40 dwarf galaxies fit right 223 00:10:15,380 --> 00:10:12,990 in here that's a lot of dwarf galaxies 224 00:10:17,060 --> 00:10:15,390 so we want to understand where they came 225 00:10:20,870 --> 00:10:17,070 from what they're doing and what we can 226 00:10:23,660 --> 00:10:20,880 learn from them so one thing we can 227 00:10:25,430 --> 00:10:23,670 learn from them is star formation we can 228 00:10:28,160 --> 00:10:25,440 learn about star formation and how it 229 00:10:30,829 --> 00:10:28,170 happened so this is an image not of 230 00:10:32,269 --> 00:10:30,839 dwarf galaxies star formation or milky 231 00:10:36,079 --> 00:10:32,279 way star formation this is for all 232 00:10:38,120 --> 00:10:36,089 galaxies so we start off with some 233 00:10:42,470 --> 00:10:38,130 really dense gas in the center in the 234 00:10:46,310 --> 00:10:42,480 red here and then that dense gas can 235 00:10:47,840 --> 00:10:46,320 collapse and form stars and then those 236 00:10:50,180 --> 00:10:47,850 stars live out their lives is either 237 00:10:53,120 --> 00:10:50,190 less massive stars or more massive stars 238 00:10:56,569 --> 00:10:53,130 eventually die but the main point of 239 00:10:59,269 --> 00:10:56,579 this image is that you need dense gas to 240 00:11:03,140 --> 00:10:59,279 form stars and that's actually really 241 00:11:04,070 --> 00:11:03,150 hard to get in some galaxies we don't 242 00:11:06,020 --> 00:11:04,080 know how 243 00:11:09,740 --> 00:11:06,030 gasps always gets to these dentinal 244 00:11:11,960 --> 00:11:09,750 states and so we kind of understand how 245 00:11:14,210 --> 00:11:11,970 that works in the milky way and I'm 246 00:11:16,460 --> 00:11:14,220 gonna take a piece of a spiral arm to 247 00:11:18,680 --> 00:11:16,470 show you that and I'm gonna blow it up 248 00:11:21,440 --> 00:11:18,690 and we're gonna pretend like it it's a 249 00:11:24,710 --> 00:11:21,450 traffic jam but in traffic jams and 250 00:11:28,490 --> 00:11:24,720 galaxies you don't have cars and trucks 251 00:11:31,220 --> 00:11:28,500 you have gas and stars so what happens 252 00:11:34,490 --> 00:11:31,230 is the spiral arm comes sweeping through 253 00:11:36,560 --> 00:11:34,500 the galaxy and the gas in the galaxy 254 00:11:39,470 --> 00:11:36,570 gets caught up in the spiral arm like a 255 00:11:41,930 --> 00:11:39,480 traffic jam and the gas starts bumping 256 00:11:43,720 --> 00:11:41,940 into each other creating regions of high 257 00:11:46,730 --> 00:11:43,730 density because it gets stirred up and 258 00:11:50,990 --> 00:11:46,740 that high density gas can then collapse 259 00:11:56,830 --> 00:11:51,000 and form stars so that's generally how 260 00:12:00,770 --> 00:11:56,840 you get stars in a spiral galaxy but 261 00:12:02,870 --> 00:12:00,780 dwarf galaxies don't have spiral arms so 262 00:12:04,700 --> 00:12:02,880 they don't have this mechanism to kind 263 00:12:07,850 --> 00:12:04,710 of stir up their gas and make regions of 264 00:12:11,720 --> 00:12:07,860 high density so we want to understand 265 00:12:15,320 --> 00:12:11,730 what causes their gas to get stirred up 266 00:12:17,570 --> 00:12:15,330 enough in order to create stars and if 267 00:12:19,730 --> 00:12:17,580 we do that then we have a more basic 268 00:12:22,670 --> 00:12:19,740 understanding of how star formation can 269 00:12:28,910 --> 00:12:22,680 happen without the aid of these extra 270 00:12:31,130 --> 00:12:28,920 spiral arms so some galaxies some dwarf 271 00:12:34,250 --> 00:12:31,140 galaxies are really good at forming 272 00:12:36,260 --> 00:12:34,260 stars and some are really bad so in 273 00:12:38,660 --> 00:12:36,270 these images I've taken their combined 274 00:12:41,150 --> 00:12:38,670 images where we've taken the Stars the 275 00:12:43,190 --> 00:12:41,160 old stars and the new stars and combined 276 00:12:45,860 --> 00:12:43,200 it with images of the gas so the gas is 277 00:12:47,270 --> 00:12:45,870 in red and the old stars are in green 278 00:12:51,050 --> 00:12:47,280 which you can see a little bit here in 279 00:12:53,660 --> 00:12:51,060 2d do to 16 and then new stars are the 280 00:12:56,140 --> 00:12:53,670 blue stars so those are little pops of 281 00:12:58,910 --> 00:12:56,150 blue you can see Indy do to 16 and 282 00:13:01,130 --> 00:12:58,920 notice to do to 16 doesn't have many 283 00:13:03,230 --> 00:13:01,140 pops of blue so it's not very good at 284 00:13:07,040 --> 00:13:03,240 forming stars right now it doesn't have 285 00:13:10,490 --> 00:13:07,050 many new stars whereas herre 36 on the 286 00:13:12,790 --> 00:13:10,500 right side has this bright white spot 287 00:13:15,920 --> 00:13:12,800 here where it's forming a ton of stars 288 00:13:17,689 --> 00:13:15,930 so it's very good at forming stars and 289 00:13:19,340 --> 00:13:17,699 we want to figure out why 290 00:13:20,960 --> 00:13:19,350 why are these dwarf galaxies so 291 00:13:23,119 --> 00:13:20,970 different what happened to one that 292 00:13:24,559 --> 00:13:23,129 didn't happen to the other to make it 293 00:13:29,569 --> 00:13:24,569 really good at forming stars are really 294 00:13:31,249 --> 00:13:29,579 bad at forming stars so I keep having 295 00:13:33,530 --> 00:13:31,259 this little symbol in the bottom right 296 00:13:35,599 --> 00:13:33,540 and as mentioned earlier little things 297 00:13:38,449 --> 00:13:35,609 as the research group that I belong to 298 00:13:40,579 --> 00:13:38,459 and I worked with for my dissertation so 299 00:13:43,849 --> 00:13:40,589 little things is actually great because 300 00:13:46,340 --> 00:13:43,859 it's an acronym and it's really fun to 301 00:13:48,289 --> 00:13:46,350 say out loud at once when you try to 302 00:13:50,869 --> 00:13:48,299 read out this acronym so where did it 303 00:13:53,900 --> 00:13:50,879 come from well first there was a group 304 00:13:57,169 --> 00:13:53,910 called things things was a group that 305 00:14:01,340 --> 00:13:57,179 studied things nearby us so they studied 306 00:14:04,629 --> 00:14:01,350 the gas and nearby massive galaxies and 307 00:14:08,539 --> 00:14:04,639 that gas is called atomic hydrogen or h1 308 00:14:11,780 --> 00:14:08,549 so their acronym is the h1 nearby 309 00:14:14,659 --> 00:14:11,790 galaxies survey or the gas nearby 310 00:14:17,059 --> 00:14:14,669 galaxies survey so that's simple kind of 311 00:14:19,549 --> 00:14:17,069 easy to remember right but then little 312 00:14:22,039 --> 00:14:19,559 things group came along and they said 313 00:14:24,739 --> 00:14:22,049 hey we want to do the same thing as 314 00:14:27,079 --> 00:14:24,749 things but we want to do it with smaller 315 00:14:29,659 --> 00:14:27,089 galaxies so we want to do it with little 316 00:14:31,999 --> 00:14:29,669 things so then they had to come up with 317 00:14:35,119 --> 00:14:32,009 an acronym that fit this of course like 318 00:14:38,269 --> 00:14:35,129 true astronomers and they got creative 319 00:14:41,059 --> 00:14:38,279 and now you're about to figure out why I 320 00:14:43,939 --> 00:14:41,069 don't ever say the full acronym out loud 321 00:14:46,400 --> 00:14:43,949 to many people it is the local irregular 322 00:14:50,629 --> 00:14:46,410 is that trace luminosity extremes the h1 323 00:14:53,749 --> 00:14:50,639 nearby galaxies surveys so just a little 324 00:14:56,119 --> 00:14:53,759 a great example of acronyms and 325 00:15:00,439 --> 00:14:56,129 astronomy and how far they can be taken 326 00:15:02,179 --> 00:15:00,449 so what did we do to get this data well 327 00:15:05,299 --> 00:15:02,189 we were looking mainly for the gas data 328 00:15:08,900 --> 00:15:05,309 and we took stellar data from other 329 00:15:10,879 --> 00:15:08,910 surveys and we got that gas data from 330 00:15:13,159 --> 00:15:10,889 The Very Large Array telescope and this 331 00:15:14,239 --> 00:15:13,169 is a beautiful picture of only part of 332 00:15:17,779 --> 00:15:14,249 that telescope 333 00:15:20,509 --> 00:15:17,789 there are actually 27 of these dishes 334 00:15:23,479 --> 00:15:20,519 that belong to this telescope and they 335 00:15:25,369 --> 00:15:23,489 together make one big telescope which is 336 00:15:26,899 --> 00:15:25,379 great because then you can move them 337 00:15:28,669 --> 00:15:26,909 closer together to make a small 338 00:15:31,060 --> 00:15:28,679 telescope or you can move them further 339 00:15:34,550 --> 00:15:31,070 apart to make a bigger telescope 340 00:15:37,730 --> 00:15:34,560 so this is a beautiful telescope which 341 00:15:39,320 --> 00:15:37,740 I've visited and we get the gas data 342 00:15:40,900 --> 00:15:39,330 from there here's me sitting on top of 343 00:15:44,210 --> 00:15:40,910 one of the dishes at the edge very 344 00:15:46,400 --> 00:15:44,220 perilous situation and then just to 345 00:15:48,410 --> 00:15:46,410 explain how big they are here's me way 346 00:15:50,660 --> 00:15:48,420 down at the bottom of one on the right 347 00:15:55,130 --> 00:15:50,670 side so these are giant dishes they're 348 00:15:56,660 --> 00:15:55,140 about 25 meters in diameter so that's 349 00:16:01,340 --> 00:15:56,670 how we got our data we got it from this 350 00:16:04,460 --> 00:16:01,350 telescope the gaseous data and we tried 351 00:16:06,590 --> 00:16:04,470 to understand what can help form stars 352 00:16:08,450 --> 00:16:06,600 in most of these galaxies and some other 353 00:16:11,390 --> 00:16:08,460 things but what I was mainly focused on 354 00:16:16,040 --> 00:16:11,400 is regulating star formation and dwarf 355 00:16:19,280 --> 00:16:16,050 galaxies so this is a list of just some 356 00:16:21,080 --> 00:16:19,290 of the ways you might be able to 357 00:16:22,550 --> 00:16:21,090 regulate star formation it's a long list 358 00:16:24,950 --> 00:16:22,560 you don't need to read it all go through 359 00:16:26,840 --> 00:16:24,960 some of them but in general it just 360 00:16:29,840 --> 00:16:26,850 gives you an idea of how many different 361 00:16:31,880 --> 00:16:29,850 ideas there are out there for forming 362 00:16:35,270 --> 00:16:31,890 stars and galaxies and we're trying to 363 00:16:38,480 --> 00:16:35,280 understand which galaxies might be doing 364 00:16:41,840 --> 00:16:38,490 these things so we're gonna focus on 365 00:16:43,850 --> 00:16:41,850 these for tonight and I did mention 366 00:16:45,260 --> 00:16:43,860 regulating star formation was my 367 00:16:48,140 --> 00:16:45,270 interest but really I was more 368 00:16:51,080 --> 00:16:48,150 interested in how galaxies can form more 369 00:16:52,640 --> 00:16:51,090 stars for tonight's talk so how do we 370 00:16:55,940 --> 00:16:52,650 get more of them now how do we get less 371 00:17:00,370 --> 00:16:55,950 of them so let's start off with our 372 00:17:05,320 --> 00:17:00,380 first way so you can have old stars 373 00:17:10,610 --> 00:17:08,180 well if we start off with a bunch of 374 00:17:13,880 --> 00:17:10,620 stars that have just formed okay these 375 00:17:16,970 --> 00:17:13,890 are the stars in the center in gas so 376 00:17:19,610 --> 00:17:16,980 the gas is the orange here so if these 377 00:17:22,550 --> 00:17:19,620 stars just formed they're giving off a 378 00:17:25,430 --> 00:17:22,560 lot of radiation if there are enough of 379 00:17:27,650 --> 00:17:25,440 them and when they give off all of this 380 00:17:30,020 --> 00:17:27,660 radiation we like to call them stellar 381 00:17:32,810 --> 00:17:30,030 winds that radiation is called a wind 382 00:17:35,840 --> 00:17:32,820 and what that wind or that radiation 383 00:17:40,790 --> 00:17:35,850 does is it keeps up the surrounding gas 384 00:17:42,650 --> 00:17:40,800 it also starts to push gas away from the 385 00:17:43,990 --> 00:17:42,660 stars because it's just radiation 386 00:17:48,250 --> 00:17:44,000 pushing away the gas 387 00:17:52,450 --> 00:17:48,260 rounds it and as it does it it creates a 388 00:17:55,360 --> 00:17:52,460 snowplow effect in the gas and remember 389 00:17:57,370 --> 00:17:55,370 we need dense gas to form stars so 390 00:18:00,430 --> 00:17:57,380 eventually these stars in the center 391 00:18:02,590 --> 00:18:00,440 will start to die off the really big 392 00:18:05,110 --> 00:18:02,600 ones and that radiation will calm down 393 00:18:07,750 --> 00:18:05,120 and so this dense gas which is kind of 394 00:18:11,620 --> 00:18:07,760 like a bubble around these stars now can 395 00:18:15,550 --> 00:18:11,630 start to cool and collapse and form new 396 00:18:17,830 --> 00:18:15,560 stars so that's how you can get new 397 00:18:22,620 --> 00:18:17,840 stars created by a bunch of old stars 398 00:18:25,630 --> 00:18:22,630 this snowplow effect in the gas so that 399 00:18:27,280 --> 00:18:25,640 does happen in some dwarf galaxies we 400 00:18:30,430 --> 00:18:27,290 think we see that and this is an image 401 00:18:34,780 --> 00:18:30,440 again some little things with galaxy IC 402 00:18:37,540 --> 00:18:34,790 1613 we're in red you have this 403 00:18:39,100 --> 00:18:37,550 beautiful gas and in the center you 404 00:18:42,520 --> 00:18:39,110 notice a bunch of green and those are 405 00:18:44,890 --> 00:18:42,530 our older stars and those older stars 406 00:18:46,900 --> 00:18:44,900 may have pushed out this gas because you 407 00:18:50,170 --> 00:18:46,910 don't see much red on top of the green 408 00:18:52,240 --> 00:18:50,180 here and given it that snowplow effect 409 00:18:55,690 --> 00:18:52,250 where now you see a bunch of blue or 410 00:18:58,630 --> 00:18:55,700 younger stars are forming in it so this 411 00:19:00,820 --> 00:18:58,640 is a beautiful nearby example of a 412 00:19:02,830 --> 00:19:00,830 galaxy that might be having the snowplow 413 00:19:05,560 --> 00:19:02,840 effect where older stars are forming new 414 00:19:08,950 --> 00:19:05,570 stars so what's our second way we're 415 00:19:12,010 --> 00:19:08,960 going to talk about so let's pump it up 416 00:19:15,040 --> 00:19:12,020 a notch let's go to gas consumption so 417 00:19:17,050 --> 00:19:15,050 galaxies eating gas this is a way you 418 00:19:21,310 --> 00:19:17,060 can get a lot of star formation all at 419 00:19:23,440 --> 00:19:21,320 once so this is an artist's image of 420 00:19:25,150 --> 00:19:23,450 that going on for a more massive galaxy 421 00:19:27,550 --> 00:19:25,160 but it still works for Dwarfs galaxies 422 00:19:30,310 --> 00:19:27,560 and with a lot of gas but we'll talk 423 00:19:33,040 --> 00:19:30,320 about little chunks of gas so the idea 424 00:19:36,790 --> 00:19:33,050 is you have a dwarf galaxy just sitting 425 00:19:39,970 --> 00:19:36,800 out there and some gas is nearby if that 426 00:19:42,220 --> 00:19:39,980 gas gets caught in the gravity of your 427 00:19:44,080 --> 00:19:42,230 galaxy it's gonna ram into the galaxy 428 00:19:45,910 --> 00:19:44,090 right because it wants to go towards the 429 00:19:49,510 --> 00:19:45,920 galaxy when it's gravitationally 430 00:19:52,419 --> 00:19:49,520 attracted and so as it comes ramming 431 00:19:55,419 --> 00:19:52,429 into the galaxy it's going to stir up 432 00:19:57,100 --> 00:19:55,429 all the gas already inside of the galaxy 433 00:20:00,039 --> 00:19:57,110 and on top of that 434 00:20:04,299 --> 00:20:00,049 it's providing fuel for future star 435 00:20:06,370 --> 00:20:04,309 formation because stars form from gas so 436 00:20:07,960 --> 00:20:06,380 you can get a burst of star formation 437 00:20:11,500 --> 00:20:07,970 and then you're on top of that giving it 438 00:20:14,980 --> 00:20:11,510 fuel for later star formation and we 439 00:20:17,440 --> 00:20:14,990 think we see that in sevens wiki 403 so 440 00:20:19,600 --> 00:20:17,450 on the left side here this is our galaxy 441 00:20:21,190 --> 00:20:19,610 sevens wiki 403 where I've combined the 442 00:20:23,410 --> 00:20:21,200 images of the stars and the gas again 443 00:20:25,830 --> 00:20:23,420 and you notice the bursts of star 444 00:20:28,240 --> 00:20:25,840 formation in the center of this one and 445 00:20:32,860 --> 00:20:28,250 then on the right side I've separated 446 00:20:35,950 --> 00:20:32,870 out just the gas in this galaxy so on 447 00:20:38,650 --> 00:20:35,960 the right side I have in gray contours 448 00:20:41,919 --> 00:20:38,660 here that's the gas that we think 449 00:20:45,669 --> 00:20:41,929 belongs to sevens with G 403 for the 450 00:20:49,870 --> 00:20:45,679 most part but we found this chunk of gas 451 00:20:52,650 --> 00:20:49,880 an orange that is moving differently 452 00:20:55,720 --> 00:20:52,660 than the rest of the gas in the galaxy 453 00:20:57,490 --> 00:20:55,730 so since it's moving so very differently 454 00:20:59,680 --> 00:20:57,500 from the rest of the gas we think this 455 00:21:03,340 --> 00:20:59,690 is a gas cloud that's coming crashing 456 00:21:05,230 --> 00:21:03,350 into the galaxy so this is an example of 457 00:21:07,720 --> 00:21:05,240 where they may be happening where this 458 00:21:10,630 --> 00:21:07,730 gas cloud is crashing into the galaxies 459 00:21:13,710 --> 00:21:10,640 stirring up the gas and then being maybe 460 00:21:16,090 --> 00:21:13,720 providing fuel for future star formation 461 00:21:20,380 --> 00:21:16,100 so that's a really cool example of where 462 00:21:22,180 --> 00:21:20,390 we think we see that now I keep 463 00:21:26,980 --> 00:21:22,190 mentioning all these names of galaxies 464 00:21:30,490 --> 00:21:26,990 IC 1613 D do 216 sevens wiki 403 what 465 00:21:32,140 --> 00:21:30,500 does that all mean well they're actually 466 00:21:35,530 --> 00:21:32,150 not that interesting of an answer their 467 00:21:40,539 --> 00:21:35,540 catalog names so for example seven 468 00:21:44,500 --> 00:21:40,549 Sookie 403 it's fritz zwicky's seventh 469 00:21:46,120 --> 00:21:44,510 catalog object zero four zero three not 470 00:21:47,710 --> 00:21:46,130 that interesting right well the reason I 471 00:21:50,320 --> 00:21:47,720 bring that up is because Fritz Zwicky 472 00:21:53,380 --> 00:21:50,330 is one of my pictorial heroes and what 473 00:21:56,110 --> 00:21:53,390 do I mean by that well he's really good 474 00:21:57,900 --> 00:21:56,120 at taking professional photos so I 475 00:22:01,000 --> 00:21:57,910 really believe that he has reached 476 00:22:02,380 --> 00:22:01,010 professional photo level experts so I'm 477 00:22:08,480 --> 00:22:02,390 going to be trying to reach this in my 478 00:22:10,310 --> 00:22:08,490 future career so just keep an eye out so 479 00:22:13,030 --> 00:22:10,320 what's our third way that we can do this 480 00:22:16,100 --> 00:22:13,040 well we can talk about interacting and 481 00:22:18,140 --> 00:22:16,110 merging dwarf galaxies we're here on the 482 00:22:19,940 --> 00:22:18,150 left we have some Zords that are 483 00:22:21,680 --> 00:22:19,950 momentarily interacting and then they 484 00:22:24,500 --> 00:22:21,690 let go and go off on their own ways and 485 00:22:27,049 --> 00:22:24,510 on the right we have some Zords that are 486 00:22:29,860 --> 00:22:27,059 merging to become a Megazord okay but 487 00:22:32,690 --> 00:22:29,870 what does that look like with galaxies 488 00:22:34,430 --> 00:22:32,700 well it looks something like this where 489 00:22:36,770 --> 00:22:34,440 this video I'm playing actually depicts 490 00:22:39,590 --> 00:22:36,780 maps of galaxies but that's okay 491 00:22:41,419 --> 00:22:39,600 works for dwarfs again and the Pops of 492 00:22:44,540 --> 00:22:41,429 blue that you can kind of see here our 493 00:22:46,820 --> 00:22:44,550 stars forming so as they pass by each 494 00:22:49,190 --> 00:22:46,830 other they're interacting and you see 495 00:22:50,840 --> 00:22:49,200 lots of pops of blue so lots of new 496 00:22:53,450 --> 00:22:50,850 stars forming so they're stirring up 497 00:22:54,620 --> 00:22:53,460 each other's gas gravitationally but 498 00:22:56,990 --> 00:22:54,630 they're caught in each other with 499 00:23:00,560 --> 00:22:57,000 gravity so they're eventually going to 500 00:23:03,650 --> 00:23:00,570 merge and as they merge you're going to 501 00:23:05,210 --> 00:23:03,660 see lots more pops of blue so as they're 502 00:23:07,730 --> 00:23:05,220 merging they're stirring up each other's 503 00:23:13,180 --> 00:23:07,740 gas a lot creating regions of high gas 504 00:23:17,090 --> 00:23:13,190 density which can then form stars but 505 00:23:19,310 --> 00:23:17,100 there is as we replay it I'm going to 506 00:23:23,660 --> 00:23:19,320 show you some signatures that 507 00:23:25,250 --> 00:23:23,670 astronomers look for when they are 508 00:23:28,280 --> 00:23:25,260 looking for these merging and 509 00:23:30,020 --> 00:23:28,290 interacting galaxies so as they interact 510 00:23:32,210 --> 00:23:30,030 they come close to each other and the 511 00:23:35,299 --> 00:23:32,220 galaxies on the right you're gonna see 512 00:23:38,690 --> 00:23:35,309 it change shape and when it changes 513 00:23:43,100 --> 00:23:38,700 shape it actually leaves these curved 514 00:23:46,549 --> 00:23:43,110 features behind and that's because the 515 00:23:49,790 --> 00:23:46,559 other galaxies it's gravity has ripped 516 00:23:53,060 --> 00:23:49,800 the stars off the outer edge and created 517 00:23:55,790 --> 00:23:53,070 these curved features so these are what 518 00:23:57,740 --> 00:23:55,800 we call tidal tails so that's something 519 00:24:02,390 --> 00:23:57,750 that astronomers look for when they're 520 00:24:05,120 --> 00:24:02,400 looking for interacting galaxies then if 521 00:24:08,180 --> 00:24:05,130 we want to look for merging galaxies 522 00:24:11,360 --> 00:24:08,190 like these to one thing we can look for 523 00:24:14,419 --> 00:24:11,370 is their centers so these two have very 524 00:24:19,040 --> 00:24:14,429 bright centers very bright cores we call 525 00:24:20,930 --> 00:24:19,050 them and as they merge you notice that 526 00:24:22,269 --> 00:24:20,940 they're bright cores don't merge 527 00:24:25,089 --> 00:24:22,279 immediately there's still 528 00:24:27,099 --> 00:24:25,099 visible for a while so if you see these 529 00:24:30,269 --> 00:24:27,109 two separate cords with a bunch of these 530 00:24:32,469 --> 00:24:30,279 titles tails or these pulled out stars 531 00:24:37,989 --> 00:24:32,479 then you know you have a merging 532 00:24:39,609 --> 00:24:37,999 galaxies situation so in Harrow 36 this 533 00:24:41,979 --> 00:24:39,619 galaxy I showed you earlier that's 534 00:24:44,950 --> 00:24:41,989 forming a ton of stars we think we see 535 00:24:46,690 --> 00:24:44,960 that so here on the left as the image I 536 00:24:49,899 --> 00:24:46,700 showed you before of the stars and the 537 00:24:52,119 --> 00:24:49,909 gas and red and the stars here in this 538 00:24:54,519 --> 00:24:52,129 bright white part are forming a lot of 539 00:24:57,820 --> 00:24:54,529 them and then on the right side have 540 00:25:00,519 --> 00:24:57,830 just pulled out the gas image so this is 541 00:25:02,739 --> 00:25:00,529 just the gas in the orange here and you 542 00:25:05,440 --> 00:25:02,749 can see going straight up there's this 543 00:25:09,070 --> 00:25:05,450 really thin feature and we think that's 544 00:25:12,999 --> 00:25:09,080 the title tail and then on top of that 545 00:25:15,940 --> 00:25:13,009 it's possible that this galaxy still has 546 00:25:17,649 --> 00:25:15,950 those two cores and it's gas visible so 547 00:25:20,680 --> 00:25:17,659 it's still settling down it's still 548 00:25:25,359 --> 00:25:20,690 mixing together so this is a possible 549 00:25:27,099 --> 00:25:25,369 example of a merged galaxy so what's our 550 00:25:29,430 --> 00:25:27,109 fourth way that we can get lots more 551 00:25:31,599 --> 00:25:29,440 stars and galaxies 552 00:25:38,279 --> 00:25:31,609 well that's through Ram pressure 553 00:25:44,950 --> 00:25:40,930 you have something very dramatic 554 00:25:48,639 --> 00:25:44,960 happening to your galaxy so the space 555 00:25:51,279 --> 00:25:48,649 between galaxies is not actually empty 556 00:25:53,259 --> 00:25:51,289 it's full of stuff stuff that galaxies 557 00:25:55,719 --> 00:25:53,269 expelled stuff that galaxies haven't 558 00:25:59,409 --> 00:25:55,729 eaten yet it's just a bunch of stuff out 559 00:26:01,719 --> 00:25:59,419 there and so if you get a galaxy like 560 00:26:05,379 --> 00:26:01,729 the one in the top left corner of this 561 00:26:09,219 --> 00:26:05,389 image here moving really fast through 562 00:26:11,649 --> 00:26:09,229 that stuff its gas is going to be ripped 563 00:26:13,749 --> 00:26:11,659 off it's just gonna be ripped straight 564 00:26:20,469 --> 00:26:13,759 off and that's the stripping part of 565 00:26:22,119 --> 00:26:20,479 this word or this phrase so as its when 566 00:26:24,609 --> 00:26:22,129 astronomers talk about Ram pressure 567 00:26:26,680 --> 00:26:24,619 stripping they don't typically talk 568 00:26:28,299 --> 00:26:26,690 about forming stars they talk about the 569 00:26:30,399 --> 00:26:28,309 death of the galaxies in terms of 570 00:26:33,269 --> 00:26:30,409 forming stars because you're ripping off 571 00:26:35,940 --> 00:26:33,279 all that fuel for star formation right 572 00:26:38,850 --> 00:26:35,950 but there 573 00:26:42,269 --> 00:26:38,860 a brief moment when this is happening to 574 00:26:45,539 --> 00:26:42,279 a galaxy where there's still gas left 575 00:26:48,539 --> 00:26:45,549 inside the galaxy and that gas is being 576 00:26:50,039 --> 00:26:48,549 stirred up a lot and so that gas that's 577 00:26:52,649 --> 00:26:50,049 being stirred up will start to form a 578 00:26:56,370 --> 00:26:52,659 lot of stars and so that's its kind of 579 00:27:00,870 --> 00:26:56,380 last burst of star formation before it 580 00:27:03,779 --> 00:27:00,880 dies well not really dies but you get 581 00:27:06,330 --> 00:27:03,789 the idea so this is a dramatic picture 582 00:27:08,370 --> 00:27:06,340 of that happening here and a very 583 00:27:10,230 --> 00:27:08,380 beautiful one with a massive galaxy 584 00:27:12,750 --> 00:27:10,240 that's moving towards the top left of 585 00:27:14,879 --> 00:27:12,760 this image and trailing behind it in 586 00:27:16,740 --> 00:27:14,889 this bluish purple color is a lot of its 587 00:27:18,350 --> 00:27:16,750 gas that's just being ripped straight 588 00:27:22,259 --> 00:27:18,360 out of it 589 00:27:26,129 --> 00:27:22,269 so with dwarf galaxies we might be 590 00:27:29,940 --> 00:27:26,139 seeing that in Markarian 178 here so 591 00:27:32,399 --> 00:27:29,950 this image on the left again is our gas 592 00:27:35,370 --> 00:27:32,409 in red and our oldest stars and green 593 00:27:37,259 --> 00:27:35,380 with our new stars in blue so there's a 594 00:27:41,820 --> 00:27:37,269 lot of star formation going on in the 595 00:27:43,919 --> 00:27:41,830 center of this galaxy but in this left 596 00:27:47,820 --> 00:27:43,929 image you notice that the red is kind of 597 00:27:50,789 --> 00:27:47,830 trailing off to this tip so that could 598 00:27:53,039 --> 00:27:50,799 be the gas that is being left behind by 599 00:27:55,230 --> 00:27:53,049 Ram pressure stripping if this galaxy is 600 00:27:57,509 --> 00:27:55,240 more moving towards the bottom left of 601 00:28:02,100 --> 00:27:57,519 this image so it's just being pulled 602 00:28:04,740 --> 00:28:02,110 straight off then on the right here I've 603 00:28:06,629 --> 00:28:04,750 taken two parts of this image I've taken 604 00:28:09,659 --> 00:28:06,639 the old stars which are in green here 605 00:28:11,789 --> 00:28:09,669 and I've taken the gas which is an 606 00:28:15,779 --> 00:28:11,799 orange so the old stars are these gray 607 00:28:18,570 --> 00:28:15,789 lines here and you notice that the stars 608 00:28:20,519 --> 00:28:18,580 the old stars don't have any gas 609 00:28:23,279 --> 00:28:20,529 covering them on the bottom left and 610 00:28:25,639 --> 00:28:23,289 that might be because that gas that used 611 00:28:28,710 --> 00:28:25,649 to be there has already been ripped off 612 00:28:31,350 --> 00:28:28,720 so this part which is forming a lot of 613 00:28:34,019 --> 00:28:31,360 stars in the middle is kind of the front 614 00:28:36,080 --> 00:28:34,029 of the galaxy that might be running into 615 00:28:38,669 --> 00:28:36,090 all of this stuff and being stirred up 616 00:28:41,399 --> 00:28:38,679 so this is a moment in this galaxy's 617 00:28:46,680 --> 00:28:41,409 life right before it may stop forming 618 00:28:48,720 --> 00:28:46,690 stars so we've gone through all 619 00:28:51,200 --> 00:28:48,730 these different ways that you can add 620 00:28:53,580 --> 00:28:51,210 more stars to your galaxy dwarf galaxies 621 00:28:55,080 --> 00:28:53,590 but there are plenty more you can feel 622 00:28:56,940 --> 00:28:55,090 free to ask me about them 623 00:28:58,050 --> 00:28:56,950 I've included one extra there but we 624 00:29:01,530 --> 00:28:58,060 definitely don't have time to go through 625 00:29:03,090 --> 00:29:01,540 that so I just want to leave you with a 626 00:29:06,980 --> 00:29:03,100 few thoughts to take home 627 00:29:09,360 --> 00:29:06,990 first of all dwarf galaxies are awesome 628 00:29:11,790 --> 00:29:09,370 second of all there are a lot of them 629 00:29:13,080 --> 00:29:11,800 nearby remember that image I showed you 630 00:29:17,280 --> 00:29:13,090 at the very beginning with all those 631 00:29:19,320 --> 00:29:17,290 blue labels also star formation and 632 00:29:20,670 --> 00:29:19,330 Joris galaxies can be triggered in a lot 633 00:29:22,800 --> 00:29:20,680 of different ways we didn't even go 634 00:29:26,700 --> 00:29:22,810 through probably half of the ideas out 635 00:29:28,470 --> 00:29:26,710 there and then last but not least Jewish 636 00:29:30,990 --> 00:29:28,480 galaxies can better help us better 637 00:29:33,420 --> 00:29:31,000 understand star formation in general 638 00:29:35,640 --> 00:29:33,430 because we don't have those big spiral 639 00:29:38,370 --> 00:29:35,650 arms helping us out so we have to figure 640 00:29:41,820 --> 00:29:38,380 out new and creative ways to get started 641 00:29:44,490 --> 00:29:41,830 to forming your galaxy I also wanted to 642 00:29:47,130 --> 00:29:44,500 just plug astronomy on tap Baltimore 643 00:29:50,130 --> 00:29:47,140 which was mentioned earlier we have 644 00:29:51,750 --> 00:29:50,140 bimonthly events last Wednesday of every 645 00:29:54,140 --> 00:29:51,760 month so if you can't get enough 646 00:29:58,080 --> 00:29:54,150 astronomy join us at declined of all 647 00:30:00,660 --> 00:29:58,090 down in Hamden and probably saying that 648 00:30:04,410 --> 00:30:00,670 name terribly wrong but dkd as most 649 00:30:06,570 --> 00:30:04,420 people know it and we sit in a bar and 650 00:30:08,760 --> 00:30:06,580 we have astronomers like myself get up 651 00:30:10,980 --> 00:30:08,770 and give you talks while you have a nice 652 00:30:14,340 --> 00:30:10,990 drink and relax so it's a really fun 653 00:30:16,260 --> 00:30:14,350 setting I heard they're just adding food 654 00:30:17,820 --> 00:30:16,270 to their menu if you want a snack well 655 00:30:20,220 --> 00:30:17,830 you listen to astronomy talks but our 656 00:30:22,350 --> 00:30:20,230 next phone will be in September 25th and 657 00:30:32,890 --> 00:30:22,360 we have a Facebook group so you can look 658 00:30:38,710 --> 00:30:35,549 [Applause] 659 00:30:42,070 --> 00:30:38,720 and I believe we have plenty of time for 660 00:30:44,500 --> 00:30:42,080 questions so alright we're waiting for 661 00:30:48,070 --> 00:30:44,510 the lovely cube so people online can 662 00:31:08,860 --> 00:30:48,080 hear us one second just Thomas is making 663 00:31:10,659 --> 00:31:08,870 his way down so my question has to do 664 00:31:13,810 --> 00:31:10,669 with black hole formation and dwarf 665 00:31:15,760 --> 00:31:13,820 galaxies I don't even know if any form 666 00:31:17,560 --> 00:31:15,770 or not but if they do can you speak a 667 00:31:19,840 --> 00:31:17,570 little bit about black hole formation 668 00:31:24,340 --> 00:31:19,850 yeah so this used to be a very touchy 669 00:31:28,960 --> 00:31:24,350 subject of mine oh no it's good now the 670 00:31:32,279 --> 00:31:28,970 so the idea that every galaxy has a 671 00:31:35,470 --> 00:31:32,289 supermassive black hole is not correct 672 00:31:38,620 --> 00:31:35,480 however dwarf galaxies can certainly 673 00:31:42,149 --> 00:31:38,630 form black holes there's a lot of recent 674 00:31:45,159 --> 00:31:42,159 research into going going into trying to 675 00:31:48,190 --> 00:31:45,169 see how many of them have what's called 676 00:31:50,980 --> 00:31:48,200 intermediate black mass black holes so a 677 00:31:55,690 --> 00:31:50,990 supermassive black hole I think is about 678 00:31:57,700 --> 00:31:55,700 a million times the mass of our Sun but 679 00:31:59,110 --> 00:31:57,710 an intermediate mass black hole can be 680 00:32:02,340 --> 00:31:59,120 anywhere from a hundred times the mass 681 00:32:05,080 --> 00:32:02,350 of our Sun to about a million and 682 00:32:07,510 --> 00:32:05,090 they're trying to figure that out 683 00:32:09,850 --> 00:32:07,520 because we believe that dwarf galaxies 684 00:32:11,980 --> 00:32:09,860 can merge or used to in the past merge 685 00:32:13,779 --> 00:32:11,990 together to become bigger galaxies 686 00:32:17,140 --> 00:32:13,789 something like direct galaxies used to 687 00:32:20,320 --> 00:32:17,150 do that and so they want to see if they 688 00:32:22,270 --> 00:32:20,330 have themselves these seeds of black 689 00:32:25,450 --> 00:32:22,280 holes to create a bigger supermassive 690 00:32:28,330 --> 00:32:25,460 black hole and there is some evidence 691 00:32:30,190 --> 00:32:28,340 for it but it's very recent research so 692 00:32:36,159 --> 00:32:30,200 I can't speak too much to the details of 693 00:32:38,730 --> 00:32:36,169 it what causes galaxies to move like 694 00:32:40,420 --> 00:32:38,740 propelled or something like that 695 00:32:43,390 --> 00:32:40,430 [Music] 696 00:32:46,000 --> 00:32:43,400 do you mean move in themselves or move 697 00:32:47,680 --> 00:32:46,010 amongst each other just moving like the 698 00:32:50,320 --> 00:32:47,690 crashing at each other and they're 699 00:32:52,720 --> 00:32:50,330 disappearing from one another and that 700 00:32:55,930 --> 00:32:52,730 momentum comes from when they were 701 00:32:58,900 --> 00:32:55,940 forming so it there's lots of reasons 702 00:33:01,390 --> 00:32:58,910 section so for example if there's a big 703 00:33:03,400 --> 00:33:01,400 cluster of galaxies their gravity of 704 00:33:05,070 --> 00:33:03,410 monks each other causes them to move 705 00:33:08,440 --> 00:33:05,080 around each other 706 00:33:10,570 --> 00:33:08,450 and when they were forming maybe that 707 00:33:12,220 --> 00:33:10,580 gas that they formed from in the star 708 00:33:14,860 --> 00:33:12,230 the dark matter that they're formed from 709 00:33:18,160 --> 00:33:14,870 may have been moving also so that all 710 00:33:20,560 --> 00:33:18,170 has to do with where they formed and how 711 00:33:25,300 --> 00:33:20,570 fast their stuff that would they form 712 00:33:30,330 --> 00:33:25,310 from was moving and also the expansion 713 00:33:35,440 --> 00:33:33,370 question about the age of dwarf galaxies 714 00:33:40,360 --> 00:33:35,450 are they generally younger or older than 715 00:33:43,810 --> 00:33:40,370 very very good question so people used 716 00:33:46,060 --> 00:33:43,820 to think that a lot of there is a subset 717 00:33:48,820 --> 00:33:46,070 of dwarf galaxies called blue compact 718 00:33:51,250 --> 00:33:48,830 dwarf galaxies that were very young and 719 00:33:53,260 --> 00:33:51,260 the reason they used to think that was 720 00:33:55,420 --> 00:33:53,270 because all we could see were their 721 00:33:58,390 --> 00:33:55,430 bright young stars because they had so 722 00:34:00,820 --> 00:33:58,400 many of them but eventually we found out 723 00:34:03,430 --> 00:34:00,830 they had this older stellar population 724 00:34:05,710 --> 00:34:03,440 that was just hiding behind these young 725 00:34:10,180 --> 00:34:05,720 stars so we think George galaxies 726 00:34:14,740 --> 00:34:10,190 generally tend to be older about you 727 00:34:17,169 --> 00:34:14,750 know as old as other galaxies but where 728 00:34:19,270 --> 00:34:17,179 there are a few galaxies that are young 729 00:34:21,220 --> 00:34:19,280 in this sense that they're they may be 730 00:34:24,399 --> 00:34:21,230 going through their first bursts of star 731 00:34:25,930 --> 00:34:24,409 formation so in that sense they're kind 732 00:34:29,169 --> 00:34:25,940 of young that they're just going through 733 00:34:31,330 --> 00:34:29,179 this first burst and you see dwarf 734 00:34:33,730 --> 00:34:31,340 galaxies mostly in the vicinity 735 00:34:36,250 --> 00:34:33,740 give me the further out you look do you 736 00:34:38,590 --> 00:34:36,260 still see the same frequency of them so 737 00:34:41,590 --> 00:34:38,600 it's actually hard to see them further 738 00:34:44,770 --> 00:34:41,600 out so we can't see them pretty far out 739 00:34:47,470 --> 00:34:44,780 but if you're talking cosmological 740 00:34:49,690 --> 00:34:47,480 distances which I do have some friends 741 00:34:51,280 --> 00:34:49,700 that work in that and we can't see them 742 00:34:54,109 --> 00:34:51,290 because they become too faint they're 743 00:34:56,960 --> 00:34:54,119 too dim we have a 744 00:35:01,299 --> 00:34:56,970 quick question online which anime is 745 00:35:03,079 --> 00:35:01,309 your animation from this is Cowboy Bebop 746 00:35:07,599 --> 00:35:03,089 Cowboy Bebop 747 00:35:13,279 --> 00:35:07,609 from the mushroom episode yeah I'm 748 00:35:15,170 --> 00:35:13,289 Edward a9 the you didn't mention the 749 00:35:19,630 --> 00:35:15,180 Magellanic Clouds are they considered 750 00:35:22,220 --> 00:35:19,640 Dwarfs I mean they're dwarf like that 751 00:35:25,130 --> 00:35:22,230 they're a little big but they are 752 00:35:27,950 --> 00:35:25,140 dwarfed within the limits of Dwarfs like 753 00:35:32,989 --> 00:35:27,960 sizes yeah so everything you talked 754 00:35:34,880 --> 00:35:32,999 about here would apply yeah yeah the 755 00:35:38,059 --> 00:35:34,890 Magellanic Clouds are a special case 756 00:35:43,120 --> 00:35:38,069 because they actually were in one of my 757 00:35:47,569 --> 00:35:43,130 images which is I said most of the light 758 00:35:49,940 --> 00:35:47,579 so the Magellanic Clouds are these two 759 00:35:51,920 --> 00:35:49,950 dots of light down here they're their 760 00:35:54,109 --> 00:35:51,930 special case because they're interacting 761 00:35:57,650 --> 00:35:54,119 with each other and the Milky Way so 762 00:36:00,380 --> 00:35:57,660 that interaction part of my talk does 763 00:36:02,420 --> 00:36:00,390 still work with them but it is a very 764 00:36:04,279 --> 00:36:02,430 complicated case because you have not 765 00:36:19,270 --> 00:36:04,289 only the milky way's gravity but each 766 00:36:19,280 --> 00:36:28,000 [Music] 767 00:36:33,800 --> 00:36:30,860 so this greenery is the older stars that 768 00:36:36,170 --> 00:36:33,810 I mentioned before so the older stars 769 00:36:37,850 --> 00:36:36,180 are not covered by the red part here 770 00:36:39,920 --> 00:36:37,860 which is the gas which is why you can 771 00:36:43,190 --> 00:36:39,930 see them so well because that gas has 772 00:36:45,970 --> 00:36:43,200 been stripped away from them so the 773 00:36:51,050 --> 00:36:45,980 glass is that is that like hydrogen 774 00:36:52,910 --> 00:36:51,060 hydrogen it's atomic hydrogen yeah it's 775 00:36:55,210 --> 00:36:52,920 the most common element in the universe 776 00:36:57,950 --> 00:36:55,220 so that's why we try to look at it 777 00:37:00,890 --> 00:36:57,960 worked out see some matters countable of 778 00:37:03,110 --> 00:37:00,900 Eduardo Custer's little custody equally 779 00:37:05,690 --> 00:37:03,120 old but they're all uniformly shaped 780 00:37:07,250 --> 00:37:05,700 they're all circles all these galaxies 781 00:37:10,130 --> 00:37:07,260 are irregular shape 782 00:37:13,070 --> 00:37:10,140 well I why are the galaxies irregular 783 00:37:15,740 --> 00:37:13,080 shape yes good um they don't have the 784 00:37:17,180 --> 00:37:15,750 gravity to hold a regular shape do they 785 00:37:19,670 --> 00:37:17,190 have the same mass as a globular cluster 786 00:37:22,280 --> 00:37:19,680 which is regular shape well I'm not 787 00:37:23,750 --> 00:37:22,290 quite sure how globular clusters form 788 00:37:26,690 --> 00:37:23,760 but my understanding is they've been 789 00:37:28,670 --> 00:37:26,700 through quite a lot of gravitational 790 00:37:31,640 --> 00:37:28,680 interaction which tends to form those 791 00:37:35,030 --> 00:37:31,650 more ball-like shapes that you see and 792 00:37:38,180 --> 00:37:35,040 globba their clusters whereas these guys 793 00:37:39,950 --> 00:37:38,190 since they're their own entities if they 794 00:37:42,620 --> 00:37:39,960 were interacting a lot with other 795 00:37:44,870 --> 00:37:42,630 galaxies they might form that same type 796 00:37:47,600 --> 00:37:44,880 of ball or football shape which is 797 00:37:52,970 --> 00:37:47,610 called an elliptical dwarf galaxy it's 798 00:37:56,000 --> 00:37:52,980 another type of galaxy this green and 799 00:37:58,940 --> 00:37:56,010 blue eyes others false colors yes okay 800 00:38:02,450 --> 00:37:58,950 so I - the others 801 00:38:04,400 --> 00:38:02,460 there's been no reason to include it to 802 00:38:07,520 --> 00:38:04,410 introduce any complexity between the 803 00:38:09,350 --> 00:38:07,530 dark matter and the visible matter you 804 00:38:11,120 --> 00:38:09,360 just assumed it always goes along 805 00:38:13,250 --> 00:38:11,130 exactly with so we have collision 806 00:38:16,730 --> 00:38:13,260 I mean ask me have you ever has there 807 00:38:19,280 --> 00:38:16,740 been any work on showing that there is 808 00:38:21,320 --> 00:38:19,290 no complexity they just do you have to 809 00:38:25,020 --> 00:38:21,330 assume no complexity it's for the dark 810 00:38:27,180 --> 00:38:25,030 matter yeah so the dark matter 811 00:38:29,220 --> 00:38:27,190 my work I just assume it's their kind of 812 00:38:31,140 --> 00:38:29,230 doing its thing but we do actually have 813 00:38:33,720 --> 00:38:31,150 little things members that work on the 814 00:38:36,570 --> 00:38:33,730 dark matter specifically and the shape 815 00:38:39,030 --> 00:38:36,580 of the dark matter and where it sits and 816 00:38:40,560 --> 00:38:39,040 that is very model dependent so there's 817 00:38:42,690 --> 00:38:40,570 still some ongoing work with dwarf 818 00:38:44,420 --> 00:38:42,700 galaxies in general trying to understand 819 00:38:47,670 --> 00:38:44,430 what their dark matter looks like and 820 00:38:50,280 --> 00:38:47,680 how the galaxies might sit in that 821 00:38:56,610 --> 00:38:50,290 potential while that gravity of the the 822 00:39:02,750 --> 00:38:56,620 Dark Matter we have another question on 823 00:39:05,180 --> 00:39:02,760 line what is the age of the Milky Way I 824 00:39:11,820 --> 00:39:05,190 don't know 825 00:39:16,350 --> 00:39:11,830 very old can you go back to the Loki way 826 00:39:24,330 --> 00:39:16,360 galaxy earth looking in and then to be 827 00:39:26,760 --> 00:39:24,340 conceptual review I know it's a good 828 00:39:29,100 --> 00:39:26,770 educated guess that the science thinks 829 00:39:31,110 --> 00:39:29,110 that's what our galaxy looks like but 830 00:39:34,170 --> 00:39:31,120 when we look at the previous picture 831 00:39:37,200 --> 00:39:34,180 what data are they working on or 832 00:39:45,120 --> 00:39:37,210 collecting to guess that it looks like a 833 00:39:46,020 --> 00:39:45,130 barred spiral with orange must be some 834 00:39:49,230 --> 00:39:46,030 work is with it 835 00:39:51,300 --> 00:39:49,240 Gaia Survey so they're actually trying 836 00:39:55,620 --> 00:39:51,310 to figure out exactly where stars are 837 00:39:58,740 --> 00:39:55,630 placed in our galaxy by measuring their 838 00:40:00,330 --> 00:39:58,750 distances and that's a lot of work and 839 00:40:02,250 --> 00:40:00,340 it's very ongoing but there are also 840 00:40:04,500 --> 00:40:02,260 other types of measurements to measure 841 00:40:07,680 --> 00:40:04,510 the location of our spiral arms for 842 00:40:11,450 --> 00:40:07,690 example in my undergraduate I did some 843 00:40:16,650 --> 00:40:11,460 research with a professor who took 844 00:40:19,260 --> 00:40:16,660 background objects so pulsars in our 845 00:40:21,480 --> 00:40:19,270 caves and we measured how their light 846 00:40:23,580 --> 00:40:21,490 rotated and this is a very complicated 847 00:40:27,230 --> 00:40:23,590 concept which I could do an entire talk 848 00:40:30,090 --> 00:40:27,240 on by itself but essentially you measure 849 00:40:32,570 --> 00:40:30,100 the polarization so you know how your 850 00:40:34,770 --> 00:40:32,580 sunglasses are polarized if you take two 851 00:40:36,390 --> 00:40:34,780 sunglasses and you that are polarized 852 00:40:38,609 --> 00:40:36,400 and you put them next to each other 853 00:40:42,079 --> 00:40:38,619 they'll block out all the light so 854 00:40:47,809 --> 00:40:42,089 that's a linear polarization up and down 855 00:40:50,430 --> 00:40:47,819 so if you try and measure how that 856 00:40:52,680 --> 00:40:50,440 polarization changes you can figure out 857 00:40:56,459 --> 00:40:52,690 how much stuff is between you and that 858 00:40:58,589 --> 00:40:56,469 light and sorry this is like not the 859 00:41:04,829 --> 00:40:58,599 most satisfactory explanation I'm sure 860 00:41:06,390 --> 00:41:04,839 but it it's called it's the rotation of 861 00:41:07,890 --> 00:41:06,400 the polarization and what it does is 862 00:41:10,380 --> 00:41:07,900 tells you how much stuff as I see you 863 00:41:13,799 --> 00:41:10,390 can measure exactly where you think the 864 00:41:18,890 --> 00:41:13,809 spiral arms are in your galaxy and it's 865 00:41:28,499 --> 00:41:22,739 you know they were able to from where 866 00:41:29,930 --> 00:41:28,509 that thing is they were able so they 867 00:41:32,579 --> 00:41:29,940 were able to figure out what's between 868 00:41:35,969 --> 00:41:32,589 that thing that we're looking at the 869 00:41:38,009 --> 00:41:35,979 background source and us so they're able 870 00:41:43,859 --> 00:41:38,019 to figure out what's how much stuff is 871 00:41:46,920 --> 00:41:43,869 in between there yeah in looking at the 872 00:41:50,120 --> 00:41:46,930 dwarf galaxies how does the tip of one 873 00:41:52,920 --> 00:41:50,130 compare in size to the Milky Way galaxy 874 00:41:54,809 --> 00:41:52,930 how does the which one the dwarf 875 00:41:57,109 --> 00:41:54,819 galaxies how does the have it how much 876 00:42:00,749 --> 00:41:57,119 smaller would they be in the Milky Way 877 00:42:04,799 --> 00:42:00,759 yeah so I put up one next to each other 878 00:42:07,109 --> 00:42:04,809 here so they're typically this dwarf 879 00:42:10,109 --> 00:42:07,119 galaxy here's one that I showed later on 880 00:42:11,700 --> 00:42:10,119 in my talk it's Markarian 178 the one 881 00:42:12,450 --> 00:42:11,710 that's possibly being Ram pressure 882 00:42:15,589 --> 00:42:12,460 stripping 883 00:42:18,719 --> 00:42:15,599 they're typically considered to be about 884 00:42:22,549 --> 00:42:18,729 125th the size of our Milky Way all the 885 00:42:28,890 --> 00:42:22,559 way up to 1/10 the size of our Milky Way 886 00:42:31,109 --> 00:42:28,900 thank you mm-hmm we have a question on 887 00:42:35,690 --> 00:42:31,119 line can you recommend some literature 888 00:42:40,019 --> 00:42:35,700 about Ram pressure stripping Alexei's Oh 889 00:42:43,140 --> 00:42:40,029 some literature so I must say I mostly 890 00:42:46,860 --> 00:42:43,150 read journal articles and that is not 891 00:42:50,640 --> 00:42:46,870 literature that most people want to read 892 00:42:52,710 --> 00:42:50,650 I I will say actually that recently just 893 00:42:55,620 --> 00:42:52,720 a few months ago we put out an article 894 00:42:57,780 --> 00:42:55,630 on Webb telescope gorg talking about how 895 00:43:01,650 --> 00:42:57,790 the James Webb Space Telescope will look 896 00:43:03,180 --> 00:43:01,660 at these exact systems so for the person 897 00:43:04,980 --> 00:43:03,190 online if you want to go to Webb 898 00:43:08,220 --> 00:43:04,990 telescope org search Ram pressure 899 00:43:10,200 --> 00:43:08,230 stripping Alexei's that will lead you 900 00:43:18,300 --> 00:43:10,210 into a whole cornucopia of literature I 901 00:43:19,260 --> 00:43:18,310 believe I also need to read those you 902 00:43:26,070 --> 00:43:19,270 can feel free to ask me questions 903 00:43:28,410 --> 00:43:26,080 afterwards too so I remember from 904 00:43:31,200 --> 00:43:28,420 decades ago that the somebody thought 905 00:43:33,720 --> 00:43:31,210 that the Sun was between arms and this 906 00:43:37,020 --> 00:43:33,730 and you now know from this picture I can 907 00:43:39,480 --> 00:43:37,030 see that we're on the unarmed alright I 908 00:43:42,780 --> 00:43:39,490 think we're close to an arm the Orion 909 00:43:54,090 --> 00:43:42,790 spur I don't know if our faculty on I 910 00:43:55,590 --> 00:43:54,100 would have to look up that article we 911 00:43:57,870 --> 00:43:55,600 hear regularly about how hard it is to 912 00:43:59,280 --> 00:43:57,880 get time and Hubble in time how hard was 913 00:44:00,720 --> 00:43:59,290 the Very Large Array which I know is 914 00:44:02,250 --> 00:44:00,730 looking for other things for you to get 915 00:44:04,620 --> 00:44:02,260 time on when you were there oh 916 00:44:10,440 --> 00:44:04,630 definitely not as hard as Hubble like 917 00:44:13,800 --> 00:44:10,450 that so the VLA it's it's not easy to 918 00:44:15,570 --> 00:44:13,810 get time on the VLA this is a beautiful 919 00:44:18,950 --> 00:44:15,580 picture of it that I showed earlier 920 00:44:21,960 --> 00:44:18,960 around but this is actually the VLA so 921 00:44:24,330 --> 00:44:21,970 it is still difficult to get time on it 922 00:44:26,550 --> 00:44:24,340 and the reason being especially because 923 00:44:29,880 --> 00:44:26,560 they just upgraded it so they made it a 924 00:44:31,710 --> 00:44:29,890 little bit better and that everyone now 925 00:44:35,700 --> 00:44:31,720 wants to use it because it's this big 926 00:44:37,830 --> 00:44:35,710 better machine but I don't know how 927 00:44:39,930 --> 00:44:37,840 oversubscribed it is I'd have to look up 928 00:44:41,610 --> 00:44:39,940 those numbers for you but I have tried a 929 00:44:49,520 --> 00:44:41,620 Hubble time and I find that's a lot 930 00:45:06,070 --> 00:44:55,130 I think in general could we get an 931 00:45:12,380 --> 00:45:10,340 if you've got that let me know yes happy 932 00:45:13,790 --> 00:45:12,390 to do so that's actually why I'm all 933 00:45:16,130 --> 00:45:13,800 dressed up today is because we had folks 934 00:45:18,200 --> 00:45:16,140 from NASA headquarters come visit us and 935 00:45:21,520 --> 00:45:18,210 we had to brief them on what we're doing 936 00:45:24,890 --> 00:45:21,530 so the latest of the James Webb is that 937 00:45:27,590 --> 00:45:24,900 as I think it was today 938 00:45:28,670 --> 00:45:27,600 there was a successful deployment of the 939 00:45:32,210 --> 00:45:28,680 secondary mirror 940 00:45:33,410 --> 00:45:32,220 so they both the pieces of James Webb 941 00:45:34,550 --> 00:45:33,420 you can look at the model over there 942 00:45:35,930 --> 00:45:34,560 it's kind of turned on its side but 943 00:45:38,270 --> 00:45:35,940 there's the top part which is the 944 00:45:39,830 --> 00:45:38,280 optical element which has all of the 945 00:45:41,390 --> 00:45:39,840 mirrors that gather the light and all of 946 00:45:43,040 --> 00:45:41,400 the instruments that analyze the light 947 00:45:45,200 --> 00:45:43,050 and then you have the bottom part which 948 00:45:47,810 --> 00:45:45,210 is the Sun shield blocking the Sun and 949 00:45:49,700 --> 00:45:47,820 all with its infrared radiation and the 950 00:45:52,100 --> 00:45:49,710 spacecraft and so currently both of 951 00:45:54,850 --> 00:45:52,110 those are two big pieces they're sitting 952 00:45:58,670 --> 00:45:54,860 in California at the Northrop Grumman 953 00:46:00,320 --> 00:45:58,680 facility and they just did a test where 954 00:46:01,700 --> 00:46:00,330 they're not together yet but they're 955 00:46:03,500 --> 00:46:01,710 talking to each other so they just said 956 00:46:06,140 --> 00:46:03,510 a test where they deployed successfully 957 00:46:07,730 --> 00:46:06,150 the secondary mirror and got everything 958 00:46:14,360 --> 00:46:07,740 working and weightless and all that 959 00:46:16,370 --> 00:46:14,370 stuff and to mean you and me in the next 960 00:46:20,060 --> 00:46:16,380 are we still recording maybe I should be 961 00:46:22,250 --> 00:46:20,070 more discreet we are in the process of 962 00:46:25,520 --> 00:46:22,260 integrating the two halves of the 963 00:46:29,180 --> 00:46:25,530 observatory so sometime in the next few 964 00:46:30,740 --> 00:46:29,190 weeks we will be mating the the top half 965 00:46:33,830 --> 00:46:30,750 and the bottom half of the observatory 966 00:46:37,310 --> 00:46:33,840 that is the final integration step for 967 00:46:39,470 --> 00:46:37,320 the observatory then they actually take 968 00:46:41,360 --> 00:46:39,480 several weeks to connect all those wires 969 00:46:45,050 --> 00:46:41,370 and make the big thing and the big thing 970 00:46:47,060 --> 00:46:45,060 work nicely together and that's 971 00:46:48,920 --> 00:46:47,070 happening over the next month or two is 972 00:46:51,110 --> 00:46:48,930 that I think they actually touchdown 973 00:46:52,520 --> 00:46:51,120 sometime in the next week or two and 974 00:46:54,980 --> 00:46:52,530 then they'll be connecting all the wires 975 00:46:56,840 --> 00:46:54,990 everything should be all set and then 976 00:46:59,480 --> 00:46:56,850 later in the fall they put it all 977 00:47:02,360 --> 00:46:59,490 through the whole testing rigmarole a 978 00:47:03,880 --> 00:47:02,370 vacuum chamber and acoustic testing 979 00:47:07,600 --> 00:47:03,890 again 980 00:47:09,570 --> 00:47:07,610 and we are still set for a march 2021 981 00:47:14,080 --> 00:47:09,580 launch date that was my meeting today 982 00:47:15,430 --> 00:47:14,090 from French Guiana and if there's any 983 00:47:17,200 --> 00:47:15,440 other specific questions I'm happy to 984 00:47:20,940 --> 00:47:17,210 answer them but that's that's for James 985 00:47:24,910 --> 00:47:23,500 we only get one shot at this one so 986 00:47:31,150 --> 00:47:24,920 we're making sure that it's right the 987 00:47:33,730 --> 00:47:31,160 first time I have two questions for you 988 00:47:36,520 --> 00:47:33,740 the first one is are there any 989 00:47:39,400 --> 00:47:36,530 particular interactions between galaxies 990 00:47:43,240 --> 00:47:39,410 like our own and these draweth galaxies 991 00:47:46,690 --> 00:47:43,250 like for instance do galaxies like ours 992 00:47:49,300 --> 00:47:46,700 break up into small galaxies or do they 993 00:47:52,630 --> 00:47:49,310 merge and become galaxies like ours or 994 00:47:54,850 --> 00:47:52,640 are they totally independent so there's 995 00:47:57,700 --> 00:47:54,860 many parts to that question of which are 996 00:48:00,190 --> 00:47:57,710 it's a very good question so at the 997 00:48:04,000 --> 00:48:00,200 beginning of the universe when galaxies 998 00:48:07,240 --> 00:48:04,010 were just forming we think that dwarf 999 00:48:11,220 --> 00:48:07,250 like galaxies existed and they combined 1000 00:48:13,930 --> 00:48:11,230 to make larger galaxies like our own now 1001 00:48:16,720 --> 00:48:13,940 there are still a lot of dwarfs left 1002 00:48:20,590 --> 00:48:16,730 over they in all like combine into these 1003 00:48:25,870 --> 00:48:20,600 and they may have formed later etc now 1004 00:48:29,950 --> 00:48:25,880 that the the Milky Way galaxy also has a 1005 00:48:32,980 --> 00:48:29,960 ton of dwarf galaxies around it and so 1006 00:48:34,390 --> 00:48:32,990 eventually it'll eat those galaxies and 1007 00:48:39,640 --> 00:48:34,400 it's currently in the process of eating 1008 00:48:41,710 --> 00:48:39,650 several galaxies one galaxy that I can 1009 00:48:45,070 --> 00:48:41,720 think of as the nearest galaxy to us 1010 00:48:49,480 --> 00:48:45,080 which is 25,000 light-years to earth and 1011 00:48:52,630 --> 00:48:49,490 it is the Canis Major dwarf and that is 1012 00:48:56,260 --> 00:48:52,640 just being torn apart by the Milky Way 1013 00:48:58,240 --> 00:48:56,270 and we it's possible now I'm not quite 1014 00:49:02,610 --> 00:48:58,250 sure where the research is on this but 1015 00:49:05,380 --> 00:49:02,620 that galaxy may have left three rings 1016 00:49:08,140 --> 00:49:05,390 around the Milky Way from going around 1017 00:49:09,910 --> 00:49:08,150 at three times so it's just being torn 1018 00:49:12,070 --> 00:49:09,920 apart by the Milky Way and it eventually 1019 00:49:14,560 --> 00:49:12,080 will merge with it and make the Milky 1020 00:49:15,569 --> 00:49:14,570 Way more massive does that answer your 1021 00:49:18,329 --> 00:49:15,579 question yes 1022 00:49:21,630 --> 00:49:18,339 but the other question I have it is this 1023 00:49:23,789 --> 00:49:21,640 in comparison of the large galaxies and 1024 00:49:26,699 --> 00:49:23,799 small galaxies if you think the 1025 00:49:29,279 --> 00:49:26,709 aggregate of the drop galaxies that are 1026 00:49:31,349 --> 00:49:29,289 within our region you said that you can 1027 00:49:33,359 --> 00:49:31,359 only see but so far away and see dwarf 1028 00:49:35,880 --> 00:49:33,369 galaxies but if you take that region 1029 00:49:38,430 --> 00:49:35,890 that you can see like how many stars 1030 00:49:40,529 --> 00:49:38,440 might be in dropped Alexei's and how 1031 00:49:43,469 --> 00:49:40,539 many would be in large galaxies like our 1032 00:49:45,599 --> 00:49:43,479 own like a 10% of them only in drunk 1033 00:49:48,059 --> 00:49:45,609 galaxies or do they make up more like 1034 00:49:49,469 --> 00:49:48,069 50% of all I don't know I would have to 1035 00:49:51,359 --> 00:49:49,479 look that up that's a really good 1036 00:49:53,339 --> 00:49:51,369 question I have not done that math yet 1037 00:49:55,410 --> 00:49:53,349 because I would have to figure out how 1038 00:49:57,479 --> 00:49:55,420 many galaxies we know of nearby and then 1039 00:49:58,890 --> 00:49:57,489 figure out their approximate masses and 1040 00:49:59,249 --> 00:49:58,900 then add them up I would have to look 1041 00:50:01,410 --> 00:49:59,259 that up 1042 00:50:04,229 --> 00:50:01,420 yeah the feeling for whether they have a 1043 00:50:06,989 --> 00:50:04,239 significant number of stars I mean I I 1044 00:50:14,099 --> 00:50:06,999 don't know yeah I would have I have no 1045 00:50:16,620 --> 00:50:14,109 idea so is anybody studying the 1046 00:50:21,150 --> 00:50:16,630 formation of solar systems within the 1047 00:50:24,029 --> 00:50:21,160 dwarf galaxies we do not have the 1048 00:50:27,630 --> 00:50:24,039 technology as far as I know to go out 1049 00:50:29,910 --> 00:50:27,640 that far because Kepler can only see so 1050 00:50:32,519 --> 00:50:29,920 far out so we're mainly looking in our 1051 00:50:34,469 --> 00:50:32,529 own galaxy for solar systems the Milky 1052 00:50:35,219 --> 00:50:34,479 Way we can barely study them in our own 1053 00:50:38,430 --> 00:50:35,229 galaxy 1054 00:50:46,170 --> 00:50:38,440 um I studied proprietary disks plane of 1055 00:50:56,060 --> 00:50:46,180 formation only in our galaxy yeah and 1056 00:51:01,610 --> 00:50:58,100 is the technology to look at other 1057 00:51:04,520 --> 00:51:01,620 galaxies for capillary like they're just 1058 00:51:07,460 --> 00:51:04,530 this yeah it is anything that's in other 1059 00:51:11,030 --> 00:51:07,470 galaxies well we can see the stars in 1060 00:51:12,650 --> 00:51:11,040 them and we can see the gas but in terms 1061 00:51:15,680 --> 00:51:12,660 of Kepler I would assume we're pretty 1062 00:51:17,900 --> 00:51:15,690 far off by the sounds of it so looking 1063 00:51:28,100 --> 00:51:17,910 at solar systems and other galaxies 1064 00:51:31,520 --> 00:51:28,110 we're quite far off any other questions 1065 00:51:39,880 --> 00:51:31,530 first speaker all right well let's give 1066 00:51:44,299 --> 00:51:42,799 Thank You dr. Ashley and thank you all 1067 00:51:46,099 --> 00:51:44,309 for coming I appreciate your support 1068 00:51:49,249 --> 00:51:46,109 very glad you're so invested in 1069 00:51:51,140 --> 00:51:49,259 astronomy as are we and again if you are 1070 00:51:54,319 --> 00:51:51,150 interested in going on the observatory 1071 00:51:57,259 --> 00:51:54,329 tour in a few minutes just meet up here 1072 00:51:59,900 --> 00:51:57,269 and you will be guided by Eleni from