Kelly Lepo

Migrating this account to @KellyLepo@scicomm.xyz. RIP Astrodon.social.

Public Key

npub1rrgqct54jdq854g5xhmfrwp8glghwxf0ctnsrwczdqs62gwuhw7sh66vty

NIP-05 Address

kellylepo@astrodon-social.mostr.pub

Profile Code

nprofile1qqsp35qv962exsr6252rta53hqn505thryhu9ecphvpxsgd9y8wth0gpz4mhxue69uhhyetvv9ujumt0wd68ytnsw43qgntd8a

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relay.mostr.pub

Author Public Key

npub1rrgqct54jdq854g5xhmfrwp8glghwxf0ctnsrwczdqs62gwuhw7sh66vty

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Last Notes

2025-05-27 20:00:05 UTC

Woah! Really cool new videos from the Goode Solar Telescope at Big Bear Solar Observatory show timelapse adaptive optics views of the Sun's corona. This one is of a solar prominence being shaped by the Sun’s magnetism.
I like the choice to color hydrogen-alpha light pink.
You should check out all of the videos (the Sun is so fluffy!):
https://nso.edu/press-release/new-adaptive-optics-shows-stunning-details-of-our-stars-atmosphere/
#Space #Astronomy #SolarObserving
https://media.astrodon.social/media_attachments/files/114/581/500/918/433/302/original/44e2d199771f5b8f.mp4

2025-05-12 19:08:58 UTC

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More resources on the Carina Nebula Complex from Universe of Learning.
https://www.universe-of-learning.org/informal-educators/science-resources/carina-nebula-complex

2025-05-12 19:08:57 UTC

One of my favorite JWST images is the Cosmic Cliffs.
See the context of how the area imaged by JWST fits into the larger Carina Nebula, and then explore what its 3D structure could be with a new visualization from Universe of Learning.
https://youtu.be/fCOUIa3GKr8?si=TdKUjIfpDIhKaMEc
#Space #Astronomy #JWST #SciArt

2025-05-12 19:08:57 UTC

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Downloadable videos, captions, and audio description are available here:
https://webbtelescope.org/contents/media/videos/2025/123/01JSZ5G3J1DVSC07WRYDKV2FZP

2025-05-09 19:02:13 UTC

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@nprofile…qum8 Just in time for #BlackHoleWeek! Thanks ArpBot.

2025-05-07 18:22:13 UTC

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@nprofile…n8sq Clickable link: https://webbtelescope.org/contents/news-releases/2025/news-2025-123

2025-05-07 18:21:38 UTC

A blast from the past.
Check out this X-ray image of the Cassiopeia A supernova remnant, taken by NASA's Einstein Observatory in 1980.
https://archive.org/details/MSFC-8003547
https://media.astrodon.social/media_attachments/files/114/464/506/092/240/628/original/2260bdd4a1f81dd5.jpg

2025-04-30 16:48:50 UTC

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@nprofile…n8sq And who could forget everyone's favorite pillars, the "Pillars of Creation" in the Eagle Nebula.
https://webbtelescope.org/contents/media/videos/2024/020/01J0KSX97KBZC2588T1FAVXAMY
https://media.astrodon.social/media_attachments/files/114/427/931/633/361/895/original/84294a31ef6a4e02.mp4

2025-04-30 16:32:44 UTC

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@nprofile…n8sq Also some good examples of pillars in the Dark Energy Camera image of the Rosette Nebula.
https://noirlab.edu/public/images/noirlab2424b/
https://media.astrodon.social/media_attachments/files/114/427/860/897/305/065/original/b8d27bf24f53c81c.jpg

2025-04-30 16:16:01 UTC

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@nprofile…n8sq Here is a favorite of mine, Westerlund 2. If you trace all of the pillars, they all point to the central star cluster.
https://science.nasa.gov/asset/hubble/westerlund-2/
https://media.astrodon.social/media_attachments/files/114/427/800/250/456/587/original/cbb94fa1079c073d.png

2025-04-23 16:10:35 UTC

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I absolutely love the ultraviolet light GALEX image that Joe DePasquale was able to make for us.
While the hot, young O and B-type stars dominate this image, I was surprised by how much of the faint emission from the nebula you can see.
https://media.astrodon.social/media_attachments/files/114/388/146/287/016/056/original/06a0089c154724b0.jpg

2025-04-23 16:10:34 UTC

To celebrate Hubble's 35th anniversary, ViewSpace released an interactive image slider that shows the new Hubble Rosette Nebula image in context.
Here is the Rosette nebula in infrared (WISE), visible (DECam), visible with the Hubble detail image, and ultraviolet light (GALEX).
https://viewspace.org/interactives/unveiling_invisible_universe/star_formation/rosette_nebula
https://media.astrodon.social/media_attachments/files/114/388/084/140/994/069/original/6392348bf56f757c.jpg
https://media.astrodon.social/media_attachments/files/114/388/084/220/039/922/original/b2c7a4ecf65723e7.jpg
https://media.astrodon.social/media_attachments/files/114/388/084/343/278/537/original/f13f6cfb18fc745c.jpg
https://media.astrodon.social/media_attachments/files/114/388/084/412/468/128/original/4e46c73106fb2e20.jpg

2025-04-23 15:41:01 UTC

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@nprofile…n8sq Clickable link: https://www.stsci.edu/contents/news-releases/2025/news-2025-013

2025-04-21 19:03:07 UTC

Ooh! NASA’s Lucy spacecraft flew by asteroid Donaldjohanson yesterday. They just released the images.
Look at that cool space potato! 🥔
https://science.nasa.gov/image-article/nasas-lucy-spacecraft-images-asteroid-donaldjohanson/
https://media.astrodon.social/media_attachments/files/114/377/484/635/219/174/original/07115cea6c470d42.mp4

2025-04-17 16:38:47 UTC

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@nprofile…kyj5 Some useful threads from BlueSky:
https://bsky.app/profile/chrislintott.bsky.social/post/3lmy5sdsv5s27
https://bsky.app/profile/distantworlds.space/post/3lmzihugafk2x
and also: https://girlandkat.com/research-blog/2023/9/17/k2-18b-we-urgently-need-to-get-our-shit-together-about-life-detection

2025-04-14 16:50:41 UTC

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Same nebula, different telescopes.
NGC 1514, the Crystal Ball Nebula, seen in mid-infrared light from the Wide-field Infrared Survey Explorer (WISE) with a 40 cm primary mirror and JWST with a 6.5 m primary mirror.
In general, the bigger your telescope mirror, the sharper the resolution.
https://webbtelescope.org/contents/media/images/2025/118/01JRDFFM4H78GZYGBDDDNXZ95Y
https://media.astrodon.social/media_attachments/files/114/337/327/245/725/378/original/8e651dd0d9498029.png

2025-04-14 16:44:43 UTC

Same nebula, different wavelengths.
NGC 1514, the Crystal Ball Nebula, seen in visible light from the Kitt Peak Visitor Center, and in mid-infrared light from JWST's MIRI instrument.
The glowing dust rings seen in the infrared are completely absent in the visible light view.
https://noirlab.edu/public/images/noao-n1514block/
https://webbtelescope.org/contents/news-releases/2025/news-2025-118
https://media.astrodon.social/media_attachments/files/114/337/300/028/369/115/original/ece268f9faac41b2.png
https://media.astrodon.social/media_attachments/files/114/337/300/755/694/617/original/62a832aced70cac0.png

2025-04-14 00:59:16 UTC

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@nprofile…qum8 It's hard to pick favorites from the Arp catalog of peculiar galaxies, but Arp 282 has to be near the top of my list.
Arp 282 looks particularly 3D to me, something that is often lost in 2D images of interacting galaxies.

2025-04-08 16:52:22 UTC

One year ago today, I was at the Indianapolis Speedway to help out at a NASA event and see my first total solar eclipse. It was a weird juxtaposition of a natural event and a very human-made environment, but overall it was awesome!
https://media.astrodon.social/media_attachments/files/114/303/314/487/911/352/original/d6072a8124dc70d5.jpg
https://media.astrodon.social/media_attachments/files/114/303/317/772/171/937/original/385d8203e1d964d4.jpg
https://media.astrodon.social/media_attachments/files/114/303/323/173/467/360/original/be41d1e2af309469.jpg
https://media.astrodon.social/media_attachments/files/114/303/325/572/851/475/original/5b56e187f2f13c3a.jpg

2025-04-07 16:56:08 UTC

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@nprofile…qum8 Image: Galaxy Triplet Arp 274
credit: NASA, ESA, STScI, Hubble Heritage Team
https://science.nasa.gov/asset/hubble/galaxy-triplet-arp-274/

2025-04-07 16:52:43 UTC

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Also, I added a bunch of pretty pictures of Arp galaxies to its database.
Go give @nprofile…qum8 a follow to get more weird galaxies in your feed.
https://media.astrodon.social/media_attachments/files/114/297/696/169/393/056/original/94175b5f08091b25.jpg

2025-04-07 16:52:43 UTC

Did some work on @nprofile…qum8 this weekend.
I was trying to figure out why it sometimes failed to post. I never did, but I did manage to break it and then fix it (hopefully?). At least now it should not get confused and double post if something goes wrong.

2025-04-02 17:28:40 UTC

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@nprofile…jqvx This is very funny since I swapped the day/moth of birth date when filling out my citizenship paperwork (which they helpfully corrected). They eventually gave me citizenship, so I think the system works.

2025-04-01 02:49:58 UTC

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@nprofile…qum8 A wider view of Arp 284, showing the companion galaxy from SDSS.
https://sky.esa.int/esasky/?target=354.0757989484056%202.1609782117240406&hips=SDSS9+color&fov=0.1227589708640816&projection=TAN&cooframe=J2000&sci=false&lang=en
https://media.astrodon.social/media_attachments/files/114/260/427/225/137/762/original/bcaf5bfe326b2a32.png

2025-03-30 06:56:09 UTC

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@nprofile…sht3 @nprofile…qum8 Yes, all large galaxies are a mess, to a greater or lesser extent.
Here is an interactive 3D simulation I recently ran across of the stellar streams from galaxies that the Milky Way is in the process of pulling apart and eating.
https://adrian.pw/visualizations/mwstreams/
https://media.astrodon.social/media_attachments/files/114/250/047/689/629/719/original/2e35d9ec074ab1d9.png

2025-03-30 01:23:33 UTC

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@nprofile…qum8 Two galaxies, three galaxies? It's hard to tell. I love the weird mess that is Arp 204.

2025-03-26 03:46:50 UTC

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@nprofile…lvsj @nprofile…n8sq Anything with a ring around it in the JWST image is probably a background galaxy.
Here is a more standard blink between the two images, pulled from frames from the video. Some of the stars do seem to move, and I think that's real. But also there might not be a perfect alignment between the two images.
https://media.astrodon.social/media_attachments/files/114/226/668/615/606/268/original/6725d624e62aa9af.mp4

2025-03-25 21:26:25 UTC

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@nprofile…lvsj @nprofile…n8sq The two images show similar infrared wavelengths. The Spitzer image is from 2006, so you may be able to pick out the slight proper motion of stars with ~20 years between images.
It's a little hard to tell because the Spitzer has a lower resolution, so the stars appear blobby.

2025-03-25 19:56:25 UTC

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@nprofile…n8sq It's me!

2025-03-25 18:55:50 UTC

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@nprofile…hjx7 This is probably the same Edith Frances Reilly who appears as a senior in the 1940 University of Pennsylvania Women’s Yearbook
https://archives.upenn.edu/wp-content/uploads/2018/02/womens-yearbook-1940.pdf
If she ever married, she probably changed her name, so finding an obituary will be tricky.
https://media.astrodon.social/media_attachments/files/114/224/580/581/407/355/original/1ece9263262b9127.png

2025-03-24 21:32:40 UTC

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@nprofile…9n6x Cool, isn't it?
A jet blown out by a forming star just happens to line up with a background spiral galaxy.

2025-03-24 19:51:30 UTC

I'll be on Maryland Public Television's Direct Connection tonight at 7 pm to talk about the new JWST image of HH 49/50, plus share some favorite JWST and Hubble images.
The theme of the evening will be "star formation" 🤩
📷 https://webbtelescope.org/contents/news-releases/2025/news-2025-112
https://media.astrodon.social/media_attachments/files/114/219/125/265/903/518/original/1a040faf18c66a5b.jpg

2025-03-21 17:32:48 UTC

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@nprofile…d9hq New telescopes also have the ability to see those little arrows that point out supernovas.
📷 https://webbtelescope.org/contents/media/images/2024/122/01HZMHJAE2DAR1YBNF5TWVPPTZ
https://media.astrodon.social/media_attachments/files/114/201/611/517/399/492/original/0179c6f2aa799fa3.png

2025-03-14 06:57:07 UTC

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And now the clouds have rolled in, so I'm putting the telescope away.
I'm glad I got to catch at least part of totality.

2025-03-14 06:49:50 UTC

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And there it is! A total lunar eclipse from Baltimore, Maryland.
If you were standing on the near side of the Moon right now, you would see the Earth eclipsing the Sun, and see all of the sunsets and sunrises on Earth simultaneously.
#LunarEclipse #TotalLunarEclipse
https://media.astrodon.social/media_attachments/files/114/159/437/455/604/040/original/5bb2c808702b5086.jpg

2025-03-14 06:15:58 UTC

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Almost there ...
#LunarEclipse #TotalLunarEclipse
https://media.astrodon.social/media_attachments/files/114/159/303/925/070/332/original/e0d62c2790ee7916.jpg
https://media.astrodon.social/media_attachments/files/114/159/304/120/077/445/original/bf5543da2bb4cc91.jpg

2025-03-14 05:32:32 UTC

So it begins ...
The partial lunar eclipse from Baltimore, Maryland.
#LunarEclipse #TotalLunarEclipse
https://media.astrodon.social/media_attachments/files/114/159/135/354/106/649/original/5f6a6ed637a6ac0b.jpg

2025-03-11 03:34:27 UTC

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@nprofile…jqdr It's reoccurring, roughly every other month. The next one is mid-May (date TBD) and then July 15.
You can sign up for the email list to get notified of new events:
https://docs.google.com/forms/d/e/1FAIpQLSelVuBeDkICegozdOc2mV-ESL64PQyR9ep3r5zgvpVKOrTsEQ/viewform

2025-03-11 01:34:57 UTC

Folks in #Baltimore! Join us for Astronomy on Tap
Wednesday, March 12 at Guilford Hall. Doors open at 7pm.
Come hear free, accessible, and fun talks from local astronomers about how cool the upcoming Roman Space Telescope is, what we learn from exploding stars, and the connections between scifi and astronomy.
Plus free swag, trivia, and AoT pint glasses for purchase!
https://media.astrodon.social/media_attachments/files/114/141/196/393/437/364/original/0eeec89a3c5a2bee.jpg

2025-03-03 21:56:34 UTC

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I also found this in the Smithsonian Natural History museum, and thought of all of you.
#mastodon
https://media.astrodon.social/media_attachments/files/114/100/707/587/149/111/original/26255f0d00567033.jpg

2025-02-28 21:14:51 UTC

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@nprofile…m0pm Clickable link, if anyone wants it:
https://bit.ly/USPhETFellow
[you have to include the https:// part for Mastodon to recognize it as a link]

2025-02-27 17:58:52 UTC

A Hubble Treasury Program used 1,000 Hubble orbits to map out the 3D structure of Andromeda's 36 dwarf satellite galaxies, helping us map out the history of our neighboring galaxy's galactic ecosystem.
This animation is based on real Hubble data. I find it delightful.
More: https://hubblesite.org/contents/news-releases/2025/news-2025-009
#Space #Hubble #Andromeda #Galaxy
https://media.astrodon.social/media_attachments/files/114/077/051/602/968/931/original/ec90cb2aaea9f96f.mp4

2025-02-24 20:25:43 UTC

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@nprofile…d7at @nprofile…3ymh @nprofile…qum8 My understanding is that while Arp was a very good astrophotographer, he had some "peculiar" ideas about galaxy dynamics.
For example, he thought that smaller galaxies didn't merge into large galaxies, instead the reverse was true — large galaxies somehow ejected small galaxies. Based on what we know now about how galaxies evolve and interact, Arp was wrong. He also believed that quasars were not supermassive black holes in very distant, high-redshift galaxies, but were instead ejected by nearby galaxies. This has also proven incorrect.
Arp persisted in his contrarian positions despite an increasingly large amount of evidence in the 1990s and 2000s.
So part of why I love the Arp catalog is that this list of beautiful, interacting, merging galaxies was created by someone who didn't believe in galaxy mergers.

2025-02-22 05:44:44 UTC

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@nprofile…m43y Good question. I was being a little vague on purpose, since I don't know all the data analysis details. But, the instruments are not misbehaving. They are working as designed, but there are limitations imposed by how light interacts with the telescope optics.
In general, all telescopes will spread out light from things that are so small and far away that they are point sources, like stars or the disks around black holes.
Light waves will interact with the edges of the mirror to make patterns. JWST has a hexagon-shaped mirror, so point sources will make a 6-sided star pattern.
The brighter the point source, the more of the pattern you will see, and the larger the star appears. You can see this in JWST images of star fields.
In the video of Sagittarius A*, we are seeing the very center of this pattern, everything else is too faint. As it gets brighter we see a bit more. There may also be other things going on, I don't know exactly how the team processed the data.
More on Webb's diffraction patterns: https://webbtelescope.org/contents/media/images/01G529MX46J7AFK61GAMSHKSSN
Globular Cluster M92: https://webbtelescope.org/contents/media/images/01GSDN0W3Z1TCD5B7HB72WM8YC
https://media.astrodon.social/media_attachments/files/114/045/837/758/054/063/original/58ad91461857099b.png
https://media.astrodon.social/media_attachments/files/114/045/902/867/160/177/original/e464833f48542edc.png

2025-02-21 20:56:15 UTC

My favorite JWST result this week: Researchers observed the brightness of the disk around the Milky Way's resident supermassive black hole, Sagittarius A*.
The changes appear to be random, generating five to six big flares per day and several small sub-flares or bursts in between. The process causing the flares might be similar to flares and magnetic reconnection events seen on the Sun, but on a much larger scale.
The black hole's disk is actually less than one pixel in size — we see it as a blurry dot that changes in size due to instrumental effects.
https://webbtelescope.org/contents/news-releases/2025/news-2025-110
https://media.astrodon.social/media_attachments/files/114/043/756/084/841/911/original/d5148513ffa46019.mp4

2025-02-21 17:27:50 UTC

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@nprofile…qum8 🤔
https://media.astrodon.social/media_attachments/files/114/043/046/242/253/510/original/7b04e57f05902b4d.webp

2025-02-20 16:04:44 UTC

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@nprofile…n8sq
https://media.astrodon.social/media_attachments/files/114/037/031/715/424/646/original/61601dfd1029aa30.jpeg

2025-02-20 05:04:29 UTC

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@nprofile…3ymh I am slightly obsessed with the Arp catalog.
I wrote a bot that posts images of galaxies in the Arp catalog twice a day @nprofile…qum8, so I've spent a lot of time looking at modern and historic images of galaxies.
It's amazing how much better the modern space- and ground-based telescope images are!
Here is Arp 321 or Hickson Compact Group 40 from Halton Arp's original Atlas of Peculiar Galaxies (1966) and the 32nd-anniversary image from Hubble.
https://ned.ipac.caltech.edu/level5/Arp/Arp81.html
https://hubblesite.org/contents/media/images/2022/012/01FYSACDTCSR43GVXBWTHDFHCT?news=true
https://media.astrodon.social/media_attachments/files/114/034/443/981/313/973/original/1ad0d7146263e345.png
https://media.astrodon.social/media_attachments/files/114/034/445/996/893/312/original/250c9a2c526eddcf.png

2025-02-16 03:04:12 UTC

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It turns out it came from a beef between Harlow Shapley and Edwin Hubble.
After Hubble proved that these objects were very far away, Shapley suggested we call them "galaxies". Up until this time, there was only one galaxy — the Milky Way.
However, Hubble was not going to let a former detractor name this new class of object. He preferred the somewhat confusing "extragalactic nebulae." Meaning that we would use "nebula" to describe clouds of gas in the Milky Way, and "island universes" outside of it — two very different objects.
It wasn't until Hubble's death in September 1953 that the term "galaxy" was widely adopted.
More info: https://ui.adsabs.harvard.edu/abs/2024JHA....55..287K%2F/abstract
2/
https://media.astrodon.social/media_attachments/files/114/011/317/793/336/246/original/458d7fadba18c23d.jpeg
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2025-02-16 03:04:12 UTC

I've been reading some old astronomy papers (as one does on a Saturday night), and was surprised to come across the term "extragalactic nebula" to describe a galaxy in a paper written in 1941.
The famous "great debate" took place in 1920, with Harlow Shapley arguing that the "spiral nebulae" were within the Milky Way and Heber Curtis arguing that they were distant "island universes".
Edwin Hubble solved this debate once and for all in 1929, by measuring the distances to several spiral nebulae like Andromeda and Triangulum, and showing they were too far away to be within the Milky Way.
So then, why were astronomers still referring to these things as nebulae into the 1940s?
1/
https://media.astrodon.social/media_attachments/files/114/011/236/781/580/800/original/b2f57d31264b84e7.png

2025-02-14 17:19:08 UTC

Ever wonder how something like the Pillars of Creation forms?
This animation shows how young, hot, massive stars carve out roughly spherical cavities in the nebulas they were born in. The densist pockets of gas and dust shield the material behind them, resisting erosion and leaving behind pillar-like protrusions.
https://webbtelescope.org/contents/media/videos/01JKRG6YA2G05YHPJWNQCVBVM6
https://media.astrodon.social/media_attachments/files/113/999/276/190/289/043/original/19e811854f9e6191.mp4

2025-02-09 19:30:33 UTC

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The Owl Nebula, also known as M97 or NGC 3587, from Gemini North GMOS. These new high-resolution images discovered clumps of denser material on the outer part of the nebula.
Fig. 2 from Ramos-Larios et al. 2024
https://ui.adsabs.harvard.edu/abs/2024MNRAS.52710123R/abstract
#SuperbOwlSunday #SuperbOwl
https://media.astrodon.social/media_attachments/files/113/975/486/125/574/534/original/1593f601cb106c63.jpeg

2025-02-09 19:30:32 UTC

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The Owl Nebula has the best illustration by William Parsons, 3rd Earl of Rosse, in the 1850 "Observations on the Nebulae".
Look at that happy little guy!
Rosse owned the 72-inch Leviathan telescope, the largest telescope in the world at the time. In this era before astronomical photography, his sketches of the structures of nebulae were hugely influential.
https://www.jstor.org/stable/108449
#SuperbOwlSunday #SuperbOwl
https://media.astrodon.social/media_attachments/files/113/975/426/862/866/151/original/01bdb7e1c2598db8.png

2025-02-09 19:30:31 UTC

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The 3D structure of the nebula likely consists of two shells of gas, formed when the star lost its outer layers at the end of its lifetime, and an hourglass-shaped central cavity excavated by the winds of the dying star.
Fig. 5. from Guerrero et al. 2003
https://ui.adsabs.harvard.edu/abs/2003AJ....125.3213G/abstract
https://media.astrodon.social/media_attachments/files/113/975/433/775/069/706/original/d51940ecb81e740d.png

2025-02-09 19:30:31 UTC

For #SuperbOwl 🦉 Sunday I give you M97, the Owl Nebula, from the 0.9-meter telescope at the Kitt Peak National Observatory
It is object 97 in Charles Messier's catalog of “fuzzy things in the night sky that are not comets”. The Owl is a planetary nebula, the remains of a sun-like star that lost its outer layers at the end of its lifetime.
Credit: NOIRLab/NSF/AURA
Source: https://noirlab.edu/public/images/noao-m97/
#SuperbOwlSunday #superb_owl #superb_owl_sunday
https://media.astrodon.social/media_attachments/files/113/975/270/211/375/640/original/282190807d724236.jpg

2025-01-30 00:32:16 UTC

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@nprofile…x3aa Alas, no. It's in-person only.

2025-01-28 19:24:56 UTC

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@nprofile…n8sq Dust in the wind
All we are is [star] dust in the [stellar] wind ...

2025-01-19 08:30:51 UTC

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Learn.Astropy.org: a new learning platform, a place to share tutorials and techniques about how to use AstroPy with the community.
https://media.astrodon.social/media_attachments/files/113/853/949/202/246/568/original/3496ae43f739c181.png
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2025-01-19 08:30:51 UTC

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And that's it for #AAS245.
I will now go back to a more sane posting volume.

2025-01-19 08:30:51 UTC

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AstroPy is in a good place. They were able to secure funding for after talking to program officers about why their proposals kept failing, and NASA put out a call in response specifically for scientific software maintenance.
One challenge going forward is transitioning the culture from a project entirely staffed by unpaid volunteers to one with paid volunteers.
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2025-01-19 08:30:50 UTC

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Getting astronomers to work together has often been compared to herding cats. But with the right structure and inceptives, you actually can heard cats.
Organized on the then new GitHub. A do-ocracy, where what gets done is determined by who wants to do it.
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2025-01-19 08:30:50 UTC

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Despite what skeptics said, Astropy has been successful and working on code has gotten people jobs. The astropy paper is one of the most cited papers in astronomy.
Work is continuing on coordinated packages like specreduce and specutils.
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2025-01-19 08:30:50 UTC

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Lessons learned:
• Build on what already exists (like SciPy and matplotlib)
• Scientists need to be open to software engineering practices
• Have a neutral partner (or at least be deliberate about ownership)
• Dream a grand vision and follow it, despite nay-sayers
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2025-01-19 08:30:49 UTC

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And the final talk of #AAS245 was the Berkeley Prize Lecture by Erik Tollerud, Clara Brasseur, and Kelle Cruz on Astropy.
In 2011, Tollerud was a grad student who wanted to write a unified library of astronomy packages. There were may astronomy packages, leading to duplicated work and incomparableness.
This somewhat naive desire started a discussion that eventually became the Astropy project.
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2025-01-19 07:02:56 UTC

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New telescopes coming online in the near future, including the Simons Observatory.
SPT and BICEP continue working together at the South Pole to look for fluctuations from the Big Bang.
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2025-01-19 07:02:55 UTC

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The current generation of ground-based CMB telescopes operate from high, dry locations like the Atacama desert in Chile and the South Pole.
The South Pole telescope completed an upgrade to SPT-3G in 2017.
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2025-01-19 07:02:55 UTC

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Plank covered the entire sky, but due to its smaller mirror, it has lower resolution.
Since they get 24 hours of darkness in the winter, SPT can take very deep images, but they only have access to the circumpolar sky.
In Chile, you can’t image as deeply, but you get access to more of the sky. So South Pole and Chilean telescopes complement each other.
Polarization measurements from SPT-3G are an independent way to determine the Hubble constant. It agrees with Plank measurements and disagrees with the local Universe measurements. The Hubble tension remains.
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2025-01-19 07:02:55 UTC

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Looking at the SPT data, we see point sources. This is washed out in the lower-resolution space-based Plank data.
Most of these points are quasars and are in known catalogs. However, there were some bright, dusty sources found with SPT that were not in any catalogs.
Follow-up observations with ALMA show these to be distant galaxies lens by a foreground galaxy into ring shapes. Spectra of the galaxies gives you a redshift from the CO line.
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2025-01-19 07:02:54 UTC

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One early project was to look for the Sunyaev-Zeldovich (SZ) effect, caused when background light from the Cosmic Microwave background scatters off of the hot gas in galaxy clusters.
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2025-01-19 07:02:54 UTC

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Next up the Heineman Prize Lecture by John Carlstrom: Past, Present, and Future Cosmic Microwave Background Surveys.
I took an intro astronomy course from Carlstrom as an undergrad, so it was cool to see him up on the stage!
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2025-01-19 07:02:54 UTC

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Degree Angular Scale Interferometer at the South Pole made observations of the CMB power spectrum in 1999-2000, a measurement of the size of the fluctuations in the cosmic microwave background in the sky.
These results agreed with the Lambda CDM model of the universe and required the presence of dark matter. The next season they returned and got polarization measurements.
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2025-01-19 04:24:01 UTC

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Future work includes more work on galactic environments and trying to incorporate very tricky microphysics like astrochemistry into the simulations.
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2025-01-19 04:24:01 UTC

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Using by combing FIRE + STARFORGE codes, you can simulate star formation on galaxy scales, and then zoom all the way in to individual stars. It's super cool.
This way you can do things like check if the IMF changes with galactic distance. It seem like very close to the central black hole (within 0.5 pc), you might preferentially form massive stars.
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2025-01-19 04:24:00 UTC

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The story of a star's life from its birth, to how long it lives, to how it eventually dies, is determined by its mass. Star-forming nebulas tend to make stars with a distribution of masses known as the Initial Mass Function (IMF).
STARFORGE can reproduce the observed IMF down to about 0.1 times the mass of the Sun.
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2025-01-19 04:24:00 UTC

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STARFORGE has my favorite videos of simulations of star-forming nebulas. The videos don't work well as screenshots, but you should really check them out.
https://starforge.space/movies.html

2025-01-19 04:24:00 UTC

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It can also create the correct distribution of binary stars with just turbulent fragmentation of the clouds of gas — meaning the stars have always formed a binary pair, they were not captured later.
STARFORGE also tells us that very small clouds will not form high-mass stars.
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2025-01-19 04:23:59 UTC

And wrapping up my #AAS245 posts - Day 4
We started off the morning with Stella Offner's plenary Lecture: The Star Formation Engine.
Offner is part of the STARFORGE collaboration, which simulates the star formation process.
Star formation involves a lot of physics at a lot of scales — from gravity, magnetic fields, and turbulence that influence how gas collapses into stars, and stellar feedback processes that destroy the surrounding nebula.
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2025-01-18 22:03:24 UTC

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@nprofile…l9nu Yes, I was also used to thinking of molecules as broad bands rather than these individual, resolvable lines. JWST spectra are banana crackers!

2025-01-18 21:59:50 UTC

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@nprofile…rsa7 The one big hit happened early on and scared everyone, but it seems like it was a rare event and we just got unlucky.
They have defined something called the Micrometeoroid Avoidance Zone (MAZ). The location of the zone changes over the course of the year, so it's mostly a scheduling issue.
JWST can still point in the at direction if really needed (for time sensitive things or solar system objects), but they try to avoid it if they can.
More: https://jwst-docs.stsci.edu/jwst-opportunities-and-policies/jwst-general-science-policies/micrometeoroid-avoidance-zone-policies-and-procedures

2025-01-18 21:52:04 UTC

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@nprofile…l9nu Meisner did show some cool, weird brown dwarf spectra that are still under review, so I can't post.
As far as I can tell, the one that I can show, in the post above, shows fairly standard molecular absorption lines from things like carbon monoxide, methane, ammonia, and water.
Molecules tend to rotate and vibrate after absorbing light in the infrared, making these comb-like bands, which JWST can resolve.
For example:
https://commons.wikimedia.org/wiki/File:Carbon_monoxide_rotational-vibrational_spectrum.png

2025-01-18 21:45:43 UTC

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@nprofile…rsa7 From my notes: JWST has been hit by about 80 detectable micrometeoroids, only one has done any significant damage.
They seem optimistic that they are appropriately babying the mirror and have avoided pointing into the micrometeoroid "wind" since cycle 2.

2025-01-18 20:57:03 UTC

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Never change astronomers: Most JWST proposals submitted a the last minute. We are all procrastinators.
New grants formula for cycle 4 should make applying for funding less of a pain all around.
Cycle 5 proposal deadline set for October 15, 2025.
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2025-01-18 20:57:03 UTC

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The degradation seen in MIRI's reddest channels has stabilized. The current performance is reflected in the updated calibration tools and Exposure Time Calculator.
Better calibration for NIRISS as well.
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2025-01-18 20:57:03 UTC

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Good news from JWST: 36 JWST press releases in 2024. JWST news articles had a potential readership larger than the population of the Earth (because people can read more than one publication more than once). Yeah!
Bad news for JWST: Possible 20% cuts to science and mission operations starting in October because of NASA budget pressure, inflation, and unrealistically low operations costs set in 2011. Boo!
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2025-01-18 20:57:02 UTC

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Instrument update:
JWST's mirror is made of up 18 individual segments. The corrections needed to keep the segments acting as one are going better than expected and are needed less frequently.
Improvements to calibrations for NIRCam and NIRSpec.
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2025-01-18 20:57:02 UTC

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• JWST has studied planet-forming disks around stars, studying their chemistry, dynamics, and longevity under different local conditions.
• It has given us beautiful spectra of exoplanet atmospheres, including detecting molecules like CO2, SiO2 in giant exoplanets.
• In the solar system, JWST has studied water and ices in the outer solar system, in moons and smaller objects, as well as studying the outer planets.
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2025-01-18 20:57:02 UTC

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JWST's prime 5-year mission ends in 2027, and will undergo its first senior review in spring 2028.
After this review, there may be some changes to how the mission operates, including the exclusive access period of JWST data, depending on community input.
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2025-01-18 20:57:01 UTC

Wrapping up day 3 of #AAS245 with the JWST town hall (yes, I know that it was Wednesday. In my defense, there was a lot going on).
JWST is awesome, working better than expected, scientifically productive, and has more than 20 years worth of propellant.
They don’t know what the ultimate lifetime will be, but want it to be multiple decades. They are confident all of the moving parts will work for at least 10 years.
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2025-01-18 20:57:01 UTC

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Some science highlights:
• JWST has observed galaxies <300 million years after the Big Bang. The current record holder for the furthest spectroscopically confirmed galaxy is shown.
• In galaxies with a redshift less than 4, JWST has studied the interconnected process of star formation, outflows, and accretion onto supermassive black holes.
• In the Milky Way, JWST had studied star-forming areas. In the Small Magellanic Clouds, it found brown dwarf candidates.
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2025-01-17 22:44:07 UTC

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@nprofile…ytnj Here are some good ones:
Science Socks et al.:
https://sciencesocks.co/pages/puzzles-of-the-universe
Blue Kazoo:
https://bluekazoo.games/collections/outerspace-jigsaw-puzzles
Nervous System:
https://n-e-r-v-o-u-s.com/shop/search_tags.php?search=spacePuzzle

2025-01-17 22:37:49 UTC

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Scott Engle - Detailing the Evolution of Red Dwarfs, and the Consequences for their Hosted Exoplanets, in Support of the Rocky Worlds DDT Program
M stars have a magnetic clock. They will slow down rotation due to stellar winds. But, we have to find stars with known ages to calibrate this. This is easier for very young and old stars, but not stars in the middle.
In the middle use common proper motion pairs, get the age of the companion, and use that to date the M star.
With the age/rotation relation down, you can measure the rotation rate of any M star, and get an age estimate. Then you can determine how the activity of M stars changes with age. #AAS245
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2025-01-17 22:37:49 UTC

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Kevin France - UV and X-ray Observations of Rocky Planet M Dwarf Host Stars: Inputs for Atmospheric Photochemistry and Escape Calculations
Higher energy light, X-ray and Extreme UV (EUV), ionizes the atmospheres of planets. This puffs up the atmosphere and leads to mass loss.
The cosmic shoreline is the cumulative effects of EUV over time. However, the cosmic shoreline is calibrated on the Sun, which has a different history of X-rays than M stars. #AAS245
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2025-01-17 22:37:48 UTC

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Jegug Ih - Do Rocky Planets around M Stars Have Atmospheres? A Statistical Approach to the Cosmic Shoreline
Hypotheses to test:
1) No planets have atmospheres
2) Atmospheres are random
3) Cosmic Shoreline hypothesis - a line dividing those with atmospheres and those without.
Statistically speaking, picking the highest signal-to-noise targets may not be the best way to confirm the cosmic shoreline. It is better to go wide, rather than deep, and follow up on promising targets with GO time. #AAS245
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2025-01-17 22:37:48 UTC

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Rafael Luque - RV characterization of planets of interest to the Rocky Worlds DDT by MAROON-X and CARMENE
Radial velocity (RV) measurements give you eccentricity, which will save JWST observing time by giving you a better estimate of the transit time. Even for planets with known or well-studied masses, RV measurements will give you better constraints. #AAS245
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2025-01-17 22:37:48 UTC

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Alessandro Sozzetti - RV characterization of planets of potential interest to the Rocky Worlds DDT by ESPRESSO
Showed RV measurement of several planets from ESPRESSO. Since these are very difficult measurements to make, the more data the better. Sozzetti advocates including planets from the K2-3 system, which seem to lie exactly on the shoreline. #AAS245
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2025-01-17 22:37:47 UTC

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Next was the special session on the STScI-led Rocky Worlds DDT Program: a search for atmospheres on rocky exoplanets around M-dwarfs.
Brandon Coy - Atmospheric Theoretical Expectations for Rocky Worlds DDT Discoveries.
Images taken with the MIRI 1500W can identify candidate atmospheres around planets, but there is a risk of false positives. So, follow-up observations are needed to confirm. #AAS245
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2025-01-17 21:25:39 UTC

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I managed to snag this cool puzzle thanks to Dylan Paré from Villanova!
It features a Herschel and MeerKAT image of the center of the Milky Way, with polarization lines from FIREPLACE (a SOFIA 214 um legacy survey). #AAS245
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2025-01-17 20:34:43 UTC

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Luckily IXPE was built pre-pandemic, but a lot of the calibration work happened under difficult conditions in 2020.
IXPE launched in 2021, and has been successfully measuring the polarization of X-ray bright objects in space, including new, detailed measurements of the Crab Nebula.
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2025-01-17 20:34:43 UTC

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It wasn't until 2007, over 30 years after OSO 8, that there was serious consideration of another X-ray polarimeter. The IXPE concept lost to GEMS. GEMS ended up being canceled due to cost overruns.
In 2014 IXPE was re-proposed and ultimately selected (hooray!) with Martin Weisskopf and Paolo Soffitta as the PIs.
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2025-01-17 20:34:42 UTC

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Martin Weisskopf began working on studying the polarization of X-ray light from astronomical objects in 1969 (~50 years before IXPE's launch).
In 1975, they were able to put an X-ray polarimeter on the OSO-8 solar satellite, and managed to get a 20 sigma result for the Crab nebula, confirming the synchrotron nature of the emission. This would be the last astronomical X-ray polarization detection until IXPE!
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