Ava Polzin
@avapolzin.bsky.social
professional nerd/astrophysics PhD candidate at UChicago
avapolzin.github.io
avapolzin.github.io
Big fan of observing in person 🔭
September 19, 2025 at 1:08 PM
Big fan of observing in person 🔭
Definitely using the novel Ji (@alexji.bsky.social) mass-based dwarf galaxy classification scheme moving forward 🔭
June 24, 2025 at 3:18 PM
Definitely using the novel Ji (@alexji.bsky.social) mass-based dwarf galaxy classification scheme moving forward 🔭
Looks like Fefe has been reading the news…
May 13, 2025 at 10:36 PM
Looks like Fefe has been reading the news…
Tomorrow! Join us — in person or online at 6:30pm Chicago time — for the last Picture an Astronomer public lecture with galactic archaeologist Anna Frebel (MIT), who will describe the cosmic origin of the heaviest elements.
More (incl. registration) at pictureanastronomer.github.io
🔭🧪👩🔬
More (incl. registration) at pictureanastronomer.github.io
🔭🧪👩🔬
February 25, 2025 at 3:57 AM
Tomorrow! Join us — in person or online at 6:30pm Chicago time — for the last Picture an Astronomer public lecture with galactic archaeologist Anna Frebel (MIT), who will describe the cosmic origin of the heaviest elements.
More (incl. registration) at pictureanastronomer.github.io
🔭🧪👩🔬
More (incl. registration) at pictureanastronomer.github.io
🔭🧪👩🔬
Join us online (tickets for in person attendance at the Adler Planetarium sold out!) for Dame Jocelyn Bell Burnell’s public lecture tomorrow night (7pm CT)!
Second to last Picture an Astronomer public lecture 🔭🧪👩🔬
More at pictureanastronomer.github.io/lectures
Second to last Picture an Astronomer public lecture 🔭🧪👩🔬
More at pictureanastronomer.github.io/lectures
February 19, 2025 at 3:53 AM
Join us online (tickets for in person attendance at the Adler Planetarium sold out!) for Dame Jocelyn Bell Burnell’s public lecture tomorrow night (7pm CT)!
Second to last Picture an Astronomer public lecture 🔭🧪👩🔬
More at pictureanastronomer.github.io/lectures
Second to last Picture an Astronomer public lecture 🔭🧪👩🔬
More at pictureanastronomer.github.io/lectures
Registration ends Feb. 15! 🔭🧪👩🔬
We encourage *all* professional astronomers/astrophysicists to attend (in person or remotely)!
More at pictureanastronomer.github.io/symposium
We encourage *all* professional astronomers/astrophysicists to attend (in person or remotely)!
More at pictureanastronomer.github.io/symposium
February 12, 2025 at 6:16 PM
Registration ends Feb. 15! 🔭🧪👩🔬
We encourage *all* professional astronomers/astrophysicists to attend (in person or remotely)!
More at pictureanastronomer.github.io/symposium
We encourage *all* professional astronomers/astrophysicists to attend (in person or remotely)!
More at pictureanastronomer.github.io/symposium
Our second Picture an Astronomer public lecture -- in person (Chicago) and online Friday!
Hear @astrokatie.com talk about the end of the Universe!
More information + registration at pictureanastronomer.github.io/lectures/
🔭🧪👩🔬
Hear @astrokatie.com talk about the end of the Universe!
More information + registration at pictureanastronomer.github.io/lectures/
🔭🧪👩🔬
February 5, 2025 at 11:13 PM
Our second Picture an Astronomer public lecture -- in person (Chicago) and online Friday!
Hear @astrokatie.com talk about the end of the Universe!
More information + registration at pictureanastronomer.github.io/lectures/
🔭🧪👩🔬
Hear @astrokatie.com talk about the end of the Universe!
More information + registration at pictureanastronomer.github.io/lectures/
🔭🧪👩🔬
Join us (in Chicago and online) for the Picture an Astronomer Kick-off Celebration in just under a week!
Lectures from, and Q&A with, astronomers at the University of Chicago! Bingo with prizes! A free book!
More, including registration, at pictureanastronomer.github.io/kickoff
🔭🧪👩🔬
Lectures from, and Q&A with, astronomers at the University of Chicago! Bingo with prizes! A free book!
More, including registration, at pictureanastronomer.github.io/kickoff
🔭🧪👩🔬
January 25, 2025 at 12:41 AM
Join us (in Chicago and online) for the Picture an Astronomer Kick-off Celebration in just under a week!
Lectures from, and Q&A with, astronomers at the University of Chicago! Bingo with prizes! A free book!
More, including registration, at pictureanastronomer.github.io/kickoff
🔭🧪👩🔬
Lectures from, and Q&A with, astronomers at the University of Chicago! Bingo with prizes! A free book!
More, including registration, at pictureanastronomer.github.io/kickoff
🔭🧪👩🔬
If our kick-off celebration (incl. a talk from @highzclouds.bsky.social) on Jan. 30 isn't sufficient diversion, come hear Dara Norman talk about global scale astronomy from the Windy City on Feb. 3!
Free for the public in person and also streamed online!
More at pictureanastronomer.github.io
🔭🧪👩🔬
Free for the public in person and also streamed online!
More at pictureanastronomer.github.io
🔭🧪👩🔬
January 21, 2025 at 2:53 AM
If our kick-off celebration (incl. a talk from @highzclouds.bsky.social) on Jan. 30 isn't sufficient diversion, come hear Dara Norman talk about global scale astronomy from the Windy City on Feb. 3!
Free for the public in person and also streamed online!
More at pictureanastronomer.github.io
🔭🧪👩🔬
Free for the public in person and also streamed online!
More at pictureanastronomer.github.io
🔭🧪👩🔬
Our Picture an Astronomer series starts in just over a week! Free to attend (in person in Chicago and online) and an incredible opportunity to engage directly with the scientists behind cutting edge astrophysics research.
More info (including registration) at pictureanastronomer.github.io
🔭🧪👩🔬
More info (including registration) at pictureanastronomer.github.io
🔭🧪👩🔬
January 20, 2025 at 12:46 AM
Our Picture an Astronomer series starts in just over a week! Free to attend (in person in Chicago and online) and an incredible opportunity to engage directly with the scientists behind cutting edge astrophysics research.
More info (including registration) at pictureanastronomer.github.io
🔭🧪👩🔬
More info (including registration) at pictureanastronomer.github.io
🔭🧪👩🔬
You can learn about this discovery directly from Jocelyn Bell Burnell during one of our Picture an Astronomer events!
More information at pictureanastronomer.github.io, including registration (in person and remote).
For astrophysicists, come to our symposium, too -- all genders welcome!
🔭🧪👩🔬
More information at pictureanastronomer.github.io, including registration (in person and remote).
For astrophysicists, come to our symposium, too -- all genders welcome!
🔭🧪👩🔬
November 28, 2024 at 8:58 PM
You can learn about this discovery directly from Jocelyn Bell Burnell during one of our Picture an Astronomer events!
More information at pictureanastronomer.github.io, including registration (in person and remote).
For astrophysicists, come to our symposium, too -- all genders welcome!
🔭🧪👩🔬
More information at pictureanastronomer.github.io, including registration (in person and remote).
For astrophysicists, come to our symposium, too -- all genders welcome!
🔭🧪👩🔬
It got a bit lost with everything else going on this week, but my (high school!) research student, Jack, has been working with me on building a low-cost home radio telescope to map Galactic 21 cm features, and his tutorial for others to do the same is now up:
arxiv.org/abs/2411.00057
🧪🔭
arxiv.org/abs/2411.00057
🧪🔭
November 9, 2024 at 5:52 PM
It got a bit lost with everything else going on this week, but my (high school!) research student, Jack, has been working with me on building a low-cost home radio telescope to map Galactic 21 cm features, and his tutorial for others to do the same is now up:
arxiv.org/abs/2411.00057
🧪🔭
arxiv.org/abs/2411.00057
🧪🔭
Perhaps more timely now than ever:
We are hosting a scientific symposium (among other events -- see pic) at UChicago, focused on promoting and retaining women in astrophysics. Symposium registration (link in next tweet) is open through Jan. 30 and we offer hybrid attendance.
🔭👩🔬🧪
We are hosting a scientific symposium (among other events -- see pic) at UChicago, focused on promoting and retaining women in astrophysics. Symposium registration (link in next tweet) is open through Jan. 30 and we offer hybrid attendance.
🔭👩🔬🧪
November 7, 2024 at 5:19 PM
Perhaps more timely now than ever:
We are hosting a scientific symposium (among other events -- see pic) at UChicago, focused on promoting and retaining women in astrophysics. Symposium registration (link in next tweet) is open through Jan. 30 and we offer hybrid attendance.
🔭👩🔬🧪
We are hosting a scientific symposium (among other events -- see pic) at UChicago, focused on promoting and retaining women in astrophysics. Symposium registration (link in next tweet) is open through Jan. 30 and we offer hybrid attendance.
🔭👩🔬🧪
Paper day! With @grumpy1.bsky.social, Vadim Semenov, and Nick Gnedin:
arxiv.org/abs/2407.11125
We find that the star formation efficiency per free-fall time has a characteristic value ~0.01 in star-forming gas regardless of local galaxy properties, likely driven by feedback and turbulence!
🔭🧪
arxiv.org/abs/2407.11125
We find that the star formation efficiency per free-fall time has a characteristic value ~0.01 in star-forming gas regardless of local galaxy properties, likely driven by feedback and turbulence!
🔭🧪
July 17, 2024 at 1:16 AM
Paper day! With @grumpy1.bsky.social, Vadim Semenov, and Nick Gnedin:
arxiv.org/abs/2407.11125
We find that the star formation efficiency per free-fall time has a characteristic value ~0.01 in star-forming gas regardless of local galaxy properties, likely driven by feedback and turbulence!
🔭🧪
arxiv.org/abs/2407.11125
We find that the star formation efficiency per free-fall time has a characteristic value ~0.01 in star-forming gas regardless of local galaxy properties, likely driven by feedback and turbulence!
🔭🧪
From my apartment in Chicago! Visible with the naked eye (and shot on iPhone)!! 🔭
May 11, 2024 at 2:40 AM
From my apartment in Chicago! Visible with the naked eye (and shot on iPhone)!! 🔭
Whoops! Apparently the transparent background to Bluesky conversion made axis labels unreadable... here are the figures as they should have appeared above: 🧪🔭
April 3, 2024 at 1:51 AM
Whoops! Apparently the transparent background to Bluesky conversion made axis labels unreadable... here are the figures as they should have appeared above: 🧪🔭
We use TNG300 from the IllustrisTNG project to make mock CHIME maps at z = 1 and 2, which we stack on (proto-)clusters in the simulation. We find that with just ~100s of clusters (consistent with current + projected catalog sizes!), it is possible to find their average HI mass! 🧪 🔭
April 3, 2024 at 1:12 AM
We use TNG300 from the IllustrisTNG project to make mock CHIME maps at z = 1 and 2, which we stack on (proto-)clusters in the simulation. We find that with just ~100s of clusters (consistent with current + projected catalog sizes!), it is possible to find their average HI mass! 🧪 🔭
Paper day! With Laura Newburgh, Priya Natarajan, and @highzclouds.bsky.social : we explore whether a 21cm intensity mapping experiment can measure the evolution of galaxy clusters' reservoir of neutral hydrogen over cosmic time. 🧪 🔭
arxiv.org/abs/2404.01382
arxiv.org/abs/2404.01382
April 3, 2024 at 1:05 AM
Paper day! With Laura Newburgh, Priya Natarajan, and @highzclouds.bsky.social : we explore whether a 21cm intensity mapping experiment can measure the evolution of galaxy clusters' reservoir of neutral hydrogen over cosmic time. 🧪 🔭
arxiv.org/abs/2404.01382
arxiv.org/abs/2404.01382
Happy International Day of Women in Science! Big thanks to the women who helped pilot the VERGE program 2 weeks ago: @malenarice.bsky.social, @candices.bsky.social, @highzclouds.bsky.social, Kala Tanaka, @cosmolooney.bsky.social, + Lindsay DeMarchi!
More about the pilot here: ow.ly/sjBE50QA07V 🔭🧪👩🔬
More about the pilot here: ow.ly/sjBE50QA07V 🔭🧪👩🔬
February 12, 2024 at 12:49 AM
Happy International Day of Women in Science! Big thanks to the women who helped pilot the VERGE program 2 weeks ago: @malenarice.bsky.social, @candices.bsky.social, @highzclouds.bsky.social, Kala Tanaka, @cosmolooney.bsky.social, + Lindsay DeMarchi!
More about the pilot here: ow.ly/sjBE50QA07V 🔭🧪👩🔬
More about the pilot here: ow.ly/sjBE50QA07V 🔭🧪👩🔬
So excited that our SIRIUS B book is now up on arXiv!
arxiv.org/abs/2312.04041
It is intended to serve as a primer for students looking to pursue astro professionally. Participants in our 2024 program will get printed copies thanks to the IAU NA-ROAD Women & Girls in Astro mini-grant. 1/
🧪🔭👩🔬
arxiv.org/abs/2312.04041
It is intended to serve as a primer for students looking to pursue astro professionally. Participants in our 2024 program will get printed copies thanks to the IAU NA-ROAD Women & Girls in Astro mini-grant. 1/
🧪🔭👩🔬
December 8, 2023 at 1:52 AM
So excited that our SIRIUS B book is now up on arXiv!
arxiv.org/abs/2312.04041
It is intended to serve as a primer for students looking to pursue astro professionally. Participants in our 2024 program will get printed copies thanks to the IAU NA-ROAD Women & Girls in Astro mini-grant. 1/
🧪🔭👩🔬
arxiv.org/abs/2312.04041
It is intended to serve as a primer for students looking to pursue astro professionally. Participants in our 2024 program will get printed copies thanks to the IAU NA-ROAD Women & Girls in Astro mini-grant. 1/
🧪🔭👩🔬
We note that these expressions should not be used to directly model star formation. We find that, while the depletion time of H2 varies by a factor of >200 across 2 dex in metallicity, the star formation rate varies by a factor of 10. In this regime, fH2 and SF are not linearly coupled.
4/4 🧪 🔭
4/4 🧪 🔭
October 18, 2023 at 12:45 AM
We note that these expressions should not be used to directly model star formation. We find that, while the depletion time of H2 varies by a factor of >200 across 2 dex in metallicity, the star formation rate varies by a factor of 10. In this regime, fH2 and SF are not linearly coupled.
4/4 🧪 🔭
4/4 🧪 🔭
Our results include two expressions for modeling molecular hydrogen, 1) for 3D grid cells and 2) for 2D maps smoothed on different spatial scales. This allows H2 to be modeled in both high-resolution galaxy simulations and semi-analytic models of galaxy formation across 0.01-1 Zsun.
3/ 🧪 🔭
3/ 🧪 🔭
October 18, 2023 at 12:43 AM
Our results include two expressions for modeling molecular hydrogen, 1) for 3D grid cells and 2) for 2D maps smoothed on different spatial scales. This allows H2 to be modeled in both high-resolution galaxy simulations and semi-analytic models of galaxy formation across 0.01-1 Zsun.
3/ 🧪 🔭
3/ 🧪 🔭
We demonstrate that the structure of the interstellar medium is heavily dependent on the metallicity (smoother at lower Z) and that the molecular gas fraction drops at < 0.1 Zsun, consistent with H2 formation timescales that are longer than the average lifetime of giant molecular clouds.
2/ 🧪 🔭
2/ 🧪 🔭
October 18, 2023 at 12:41 AM
We demonstrate that the structure of the interstellar medium is heavily dependent on the metallicity (smoother at lower Z) and that the molecular gas fraction drops at < 0.1 Zsun, consistent with H2 formation timescales that are longer than the average lifetime of giant molecular clouds.
2/ 🧪 🔭
2/ 🧪 🔭
New paper out today with @grumpy1.bsky.social, Vadim Semenov, and Nick Gnedin: arxiv.org/abs/2310.10712
We share analytic prescriptions to accurately model molecular hydrogen in the ISM based on gas density, metallicity, and ionizing radiation field in low metallicity galaxies.
1/ 🧪 🔭
We share analytic prescriptions to accurately model molecular hydrogen in the ISM based on gas density, metallicity, and ionizing radiation field in low metallicity galaxies.
1/ 🧪 🔭
October 18, 2023 at 12:40 AM
New paper out today with @grumpy1.bsky.social, Vadim Semenov, and Nick Gnedin: arxiv.org/abs/2310.10712
We share analytic prescriptions to accurately model molecular hydrogen in the ISM based on gas density, metallicity, and ionizing radiation field in low metallicity galaxies.
1/ 🧪 🔭
We share analytic prescriptions to accurately model molecular hydrogen in the ISM based on gas density, metallicity, and ionizing radiation field in low metallicity galaxies.
1/ 🧪 🔭
Since our paper looking at the phase space of X-ray transients was accepted ( arxiv.org/abs/2211.01232, updated version on arXiv tomorrow), we can release the light curve data we used for the paper + a small package to plot and classify X-ray light curves :)
github.com/avapolzin/X-...
1/ 🧪 🔭
github.com/avapolzin/X-...
1/ 🧪 🔭
September 5, 2023 at 8:08 PM
Since our paper looking at the phase space of X-ray transients was accepted ( arxiv.org/abs/2211.01232, updated version on arXiv tomorrow), we can release the light curve data we used for the paper + a small package to plot and classify X-ray light curves :)
github.com/avapolzin/X-...
1/ 🧪 🔭
github.com/avapolzin/X-...
1/ 🧪 🔭