The StarXiv ✨ podcast
@starxiv.bsky.social
A podcast where Payel Das (@payeldas.bsky.social) and Michelle Collins (@runningastronomer.bsky.social) discuss papers from astroph
Starxiv.com
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Starxiv.com
Spotify - https://shorturl.at/xdTFw
Apple - https://shorturl.at/nKFNj
RSS - https://rss.com/podcasts/starxiv
Payel's second paper claims a expansion of the universe that is decelerating rather than accelerating after correcting for a correlation between age and magnitude of Type 1a supernovae 🔭 ☄️. Find out more at arxiv.org/abs/2510.13121.
November 12, 2025 at 1:43 PM
Payel's second paper claims a expansion of the universe that is decelerating rather than accelerating after correcting for a correlation between age and magnitude of Type 1a supernovae 🔭 ☄️. Find out more at arxiv.org/abs/2510.13121.
Payel's first paper finds bona-fide young alpha-enriched stars in the Milky Way! An unexpected find as alpha enrichment usually happens early in a chemical evolution history 🔭 ☄️. Find out more at arxiv.org/pdf/2510.15654.
November 12, 2025 at 11:23 AM
Payel's first paper finds bona-fide young alpha-enriched stars in the Milky Way! An unexpected find as alpha enrichment usually happens early in a chemical evolution history 🔭 ☄️. Find out more at arxiv.org/pdf/2510.15654.
☄️ Michelle's first paper constrains the birth cluster of the Sun. Using N-body simulations and the orbital properties of the Sednoids in the outer Solar system, they can improve constraints on the density of, and time the Sun spent in, the cluster by an order of magnitude! 🔭 arxiv.org/abs/2510.19910
November 12, 2025 at 10:15 AM
☄️ Michelle's first paper constrains the birth cluster of the Sun. Using N-body simulations and the orbital properties of the Sednoids in the outer Solar system, they can improve constraints on the density of, and time the Sun spent in, the cluster by an order of magnitude! 🔭 arxiv.org/abs/2510.19910
We give a shout out to Benty Fields this episode. It's a great resource for finding and tracking papers. Support them if you can ☄️🔭
I've just subscribed to support Benty Fields, my go to resource for looking at the arxiv and organising journal clubs (including our @starxiv.bsky.social one). Support them if you can! www.benty-fields.com/support
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November 12, 2025 at 9:36 AM
We give a shout out to Benty Fields this episode. It's a great resource for finding and tracking papers. Support them if you can ☄️🔭
Episode 24 of the StarXiv is out! Tune in as Payel and Michelle discuss the latest from the astro-arXiv, including young, high alpha stars, intermediate black holes, solar flares, Euclid lenses and more! Listen below, on Spotify or wherever you get podcasts 🔭 🧪
November 12, 2025 at 8:01 AM
Episode 24 of the StarXiv is out! Tune in as Payel and Michelle discuss the latest from the astro-arXiv, including young, high alpha stars, intermediate black holes, solar flares, Euclid lenses and more! Listen below, on Spotify or wherever you get podcasts 🔭 🧪
Episode 24: Strong lenses, Solar Flares and young, high alpha stars
In this episode, Michelle and Payel explore various astrophysical topics, including the Solar birth cluster, young stars, the formation of intermediate mass black holes, and the universe's decelerated expansion. They also discuss…
In this episode, Michelle and Payel explore various astrophysical topics, including the Solar birth cluster, young stars, the formation of intermediate mass black holes, and the universe's decelerated expansion. They also discuss…
Episode 24: Strong lenses, Solar Flares and young, high alpha stars
In this episode, Michelle and Payel explore various astrophysical topics, including the Solar birth cluster, young stars, the formation of intermediate mass black holes, and the universe's decelerated expansion. They also discuss strong lens detection by Euclid and solar flare predictions.
starxiv.com
November 12, 2025 at 6:08 AM
Episode 24: Strong lenses, Solar Flares and young, high alpha stars
In this episode, Michelle and Payel explore various astrophysical topics, including the Solar birth cluster, young stars, the formation of intermediate mass black holes, and the universe's decelerated expansion. They also discuss…
In this episode, Michelle and Payel explore various astrophysical topics, including the Solar birth cluster, young stars, the formation of intermediate mass black holes, and the universe's decelerated expansion. They also discuss…
Owing to a technical hiccup, the StarXiv will be arriving a little later this week. Expect to hear Michelle and Payel chat about the latest from astro-ph this Wednesday instead! It'll be worth the wait ☄️ 🔭
November 10, 2025 at 8:00 AM
Owing to a technical hiccup, the StarXiv will be arriving a little later this week. Expect to hear Michelle and Payel chat about the latest from astro-ph this Wednesday instead! It'll be worth the wait ☄️ 🔭
Michelle's final paper discussed the 'failed' galaxies. Thought to be living in massive dark matter halos that have formed fewer stars than expected, this population is poorly undertsood. This paper looks for their progenitors in the MAGNETICUM simulations 🔭 ☄️https://arxiv.org/abs/2510.04416
October 27, 2025 at 5:20 PM
Michelle's final paper discussed the 'failed' galaxies. Thought to be living in massive dark matter halos that have formed fewer stars than expected, this population is poorly undertsood. This paper looks for their progenitors in the MAGNETICUM simulations 🔭 ☄️https://arxiv.org/abs/2510.04416
Nicole’s third paper reported two RR Lyrae stars enriched in heavy s-process elements, a rare class previously represented only by TY Gruis. Their chemistry could reveal ancient mass transfer from AGB companions. arxiv.org/abs/2510.15723 🔭☄️
![[Eu/Fe] vs. [La/Fe] ratios for CEMP-r and CEMP-s stars by Masseron et al. (2010), CEMP-s stars by Roederer et al. (2014), Ba stars by Roriz et al. (2021), and the s-rich RRLs DQ Hya and TY Gruis. The dashed line is the 1:1 relationship.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cugc4wn2mruqtvx7lm2kztiy/bafkreieanhu63wf4htgowyjhqjr76uesk7fa5jqudes7hp6zvhj6uyptga@jpeg)
October 27, 2025 at 12:36 PM
Nicole’s third paper reported two RR Lyrae stars enriched in heavy s-process elements, a rare class previously represented only by TY Gruis. Their chemistry could reveal ancient mass transfer from AGB companions. arxiv.org/abs/2510.15723 🔭☄️
In Michelle's second paper, she updates us all on the offensively faint Ursa Major III/UNIONS 1 stellar association. Is it a galaxy wtih dark matter or a star cluster? This new paper searches for signs of dark matter and/or binary stars to answer this question! arxiv.org/abs/2510.02431 🔭 ☄️
October 27, 2025 at 11:35 AM
In Michelle's second paper, she updates us all on the offensively faint Ursa Major III/UNIONS 1 stellar association. Is it a galaxy wtih dark matter or a star cluster? This new paper searches for signs of dark matter and/or binary stars to answer this question! arxiv.org/abs/2510.02431 🔭 ☄️
Nicole’s second paper showed our Galaxy’s oldest stars mark a dense proto-Galaxy at its center, mirroring compaction-driven starbursts seen in Milky Way–like Auriga simulations that shaped the early, central galaxy. arxiv.org/abs/2510.17693 🔭☄️
October 27, 2025 at 10:42 AM
Nicole’s second paper showed our Galaxy’s oldest stars mark a dense proto-Galaxy at its center, mirroring compaction-driven starbursts seen in Milky Way–like Auriga simulations that shaped the early, central galaxy. arxiv.org/abs/2510.17693 🔭☄️
Michelle's first paper discussed MEGATRON! No, it's not some sort of transformer, but a neat suite of simulations that can help us understand what sets the metallicity of the faintest galaxies. Tune in for more! 🔭 ☄️ arxiv.org/abs/2510.05232
October 27, 2025 at 9:36 AM
Michelle's first paper discussed MEGATRON! No, it's not some sort of transformer, but a neat suite of simulations that can help us understand what sets the metallicity of the faintest galaxies. Tune in for more! 🔭 ☄️ arxiv.org/abs/2510.05232
Episode 23 has dropped! Tune in to hear about faint galaxies, failed galaxies and how binaries are always causing trouble. 🔭☄️ starxiv.com/2025/10/27/e...
Episode 23 – Failed galaxies, faint galaxies, and the proto-Galaxy
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation…
starxiv.com
October 27, 2025 at 9:21 AM
Episode 23 has dropped! Tune in to hear about faint galaxies, failed galaxies and how binaries are always causing trouble. 🔭☄️ starxiv.com/2025/10/27/e...
Nicole’s first paper showed that quasi-stars, black holes cocooned in stellar envelopes, can reproduce JWST’s “Little Red Dots,” matching their red colours and Balmer breaks. These could be SMBHs in formation. arxiv.org/abs/2510.17952 🔭☄️
![Predicted SEDs of a 10^6 M⊙ total mass, late-stage quasi-star both on its own (black dashed line) and embedded in a host galaxy (solid blue line) compared with JWST observations of LRDs (red) that includes the emission from the host stellar component with masses ∼10^9.5 M⊙. The top row shows comparisons with UNCOVER-45924 (I. Labbe et al., 2024) and the bottom row with MoM-BH*-1 (R. P. Naidu et al., 2025). We show models with (left) and without (right) dust. Semi-synthetic models of quasi-stars embedded in a host galaxy are shown in blue, using hosts properties inferred for UNCOVER-24996 and MoM-UDS-948311 respectively. The faded colors surrounding the lines represent 1σ uncertainties in JWST measurements. Gray dashed lines indicate key wavelengths: the Balmer break (H∞), Hγ, Hβ, [OIII], and both CaII lines. Discrepancies in emission lines likely arise from the use of LTE atmospheres at nonzero metallicity, particularly in the Hβ emission and CaII absorption lines - these are discussed in Sec. 2.2. Shaded regions indicate the far-UV and NIR approach, highlighting a few of the well fit continuum regions discussed in Sec. 3. The stellar parameters of the quasi-star model at this point are Teff=6241 K, log(g)=−0.003, and Z=0.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cugc4wn2mruqtvx7lm2kztiy/bafkreihl6ovaillakosqgxbqbas2th4gwg2hvaglvrjk4hjepp6dxf54qe@jpeg)
October 27, 2025 at 9:09 AM
Nicole’s first paper showed that quasi-stars, black holes cocooned in stellar envelopes, can reproduce JWST’s “Little Red Dots,” matching their red colours and Balmer breaks. These could be SMBHs in formation. arxiv.org/abs/2510.17952 🔭☄️
Episode 23 – Failed galaxies, faint galaxies, and the proto-Galaxy
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation to Little Red Dots, and…
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation to Little Red Dots, and…
Episode 23 – Failed galaxies, faint galaxies, and the proto-Galaxy
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation to Little Red Dots, and discussing whether UNIONS 1 is a galaxy or a star cluster. Listen on major podcast platforms.
starxiv.com
October 27, 2025 at 6:12 AM
Episode 23 – Failed galaxies, faint galaxies, and the proto-Galaxy
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation to Little Red Dots, and…
In this episode, Michelle and Nicole explore the chemistry of faint galaxies and RR-Lyrae stars, tracing the proto-Galaxy, discussing the failure of some galaxies, examining quasi-stars in relation to Little Red Dots, and…
Nicole’s last paper traced the inner Milky Way’s past using super-metal-rich stars in the solar neighbourhood. Their age distribution reveals six starburst episodes, a bursty formation history likely driven by bars, mergers, and interactions. arxiv.org/abs/2510.02238 🔭☄️
![Integrated stellar age distribution of the stars within 0.6 kpc of the plane of the disc (|z|<0.6 kpc). We divide it into total (including all stars, shaded black area); metal-rich (considering only stars with [M/H] ≥0.3, red); and rest (stars with [M/H] < 0.3, blue).](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cugc4wn2mruqtvx7lm2kztiy/bafkreibsk2mjqhcr4txvstp4dpznp3o5lzqnfq674bgwwaxyth7ssvzpgy@jpeg)
October 13, 2025 at 2:11 PM
Nicole’s last paper traced the inner Milky Way’s past using super-metal-rich stars in the solar neighbourhood. Their age distribution reveals six starburst episodes, a bursty formation history likely driven by bars, mergers, and interactions. arxiv.org/abs/2510.02238 🔭☄️
In Payel's second paper, she discusses a new approach for finding Einstein rings using spectra and images. The authors find 2164 new lens candidates in DESI DR1, and a new category of 318 “dimple-lens” candidates that may represent dwarf galaxy lensing.
arxiv.org/pdf/2509.16033
arxiv.org/pdf/2509.16033
October 13, 2025 at 12:45 PM
In Payel's second paper, she discusses a new approach for finding Einstein rings using spectra and images. The authors find 2164 new lens candidates in DESI DR1, and a new category of 318 “dimple-lens” candidates that may represent dwarf galaxy lensing.
arxiv.org/pdf/2509.16033
arxiv.org/pdf/2509.16033
Nicole’s next paper looked at rare radio objects found by the RAD@home citizen-science collaboratory. One of these is an Odd Radio Circle (ORC) with intersecting ~300 kpc rings, pointing to a relic synchrotron origin. arxiv.org/abs/2510.01999 🔭☄️
October 13, 2025 at 11:01 AM
Nicole’s next paper looked at rare radio objects found by the RAD@home citizen-science collaboratory. One of these is an Odd Radio Circle (ORC) with intersecting ~300 kpc rings, pointing to a relic synchrotron origin. arxiv.org/abs/2510.01999 🔭☄️
In Payel's first paper, she discusses a paper that claims a bona fide discovery of an intermediate-age RR Lyra! Always thought to have been a safe bet indicator of a metal-poor and old stellar population. Found out more here:
arxiv.org/abs/2509.22336
arxiv.org/abs/2509.22336
October 13, 2025 at 10:13 AM
In Payel's first paper, she discusses a paper that claims a bona fide discovery of an intermediate-age RR Lyra! Always thought to have been a safe bet indicator of a metal-poor and old stellar population. Found out more here:
arxiv.org/abs/2509.22336
arxiv.org/abs/2509.22336
Episode 22 – ORCs, rings, and Galactic histories
In this episode, Payel and Nicole discuss what happens to the metallicity gradient of a satellite galaxy after merging, the existence of intermediate-age RR lyrae and radio rings, and much more! Have a listen at starxiv.com/2025/10/13/e....
In this episode, Payel and Nicole discuss what happens to the metallicity gradient of a satellite galaxy after merging, the existence of intermediate-age RR lyrae and radio rings, and much more! Have a listen at starxiv.com/2025/10/13/e....
Episode 22 – ORCs, rings, and Galactic histories
In this episode, Payel and Nicole discuss what happens to the metallicity gradient of a satellite galaxy after it merges with its host, the existence of intermediate-age RR lyrae and radio rings, t…
starxiv.com
October 13, 2025 at 10:13 AM
Episode 22 – ORCs, rings, and Galactic histories
In this episode, Payel and Nicole discuss what happens to the metallicity gradient of a satellite galaxy after merging, the existence of intermediate-age RR lyrae and radio rings, and much more! Have a listen at starxiv.com/2025/10/13/e....
In this episode, Payel and Nicole discuss what happens to the metallicity gradient of a satellite galaxy after merging, the existence of intermediate-age RR lyrae and radio rings, and much more! Have a listen at starxiv.com/2025/10/13/e....
Nicole’s first paper looked at how the Gaia-Enceladus/Sausage merger erased its progenitor’s radial [Fe/H] gradient. Simulations show 78–98% of that gradient is lost to tidal mixing, but average trends survive, offering clues to past mergers. arxiv.org/abs/2509.24705 🔭☄️
![The pre-merger and post-merger picture of GES in Auriga. The sub-panels contain the XY projection of the GES progenitor coloured by the average [Fe/H] along the z axis in the first column where redder means higher [Fe/H], the 2D histogram of [Fe/H] vs RGES in the second column, and the 2D histogram of [Fe/H] vs orbital energy in the third column. The mean values of [Fe/H] are denoted with red circles for the trends against RGES and orbital energy, with the best-fit linear (blue) and exponential (orange) relations over-plotted. The [Fe/H] vs Rhost panel is coloured by RGES while the [Fe/H] vs present-day orbital energy panel is coloured by the orbital energy in the GES progenitor.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:cugc4wn2mruqtvx7lm2kztiy/bafkreibll4pyy7yasddw5bdzwfiuydaq5adu35bo56qlg4otleoswetxwm@jpeg)
October 13, 2025 at 9:00 AM
Nicole’s first paper looked at how the Gaia-Enceladus/Sausage merger erased its progenitor’s radial [Fe/H] gradient. Simulations show 78–98% of that gradient is lost to tidal mixing, but average trends survive, offering clues to past mergers. arxiv.org/abs/2509.24705 🔭☄️
Episode 21 – Mercury, chemistry and quasi periodic eruptions
In this episode, Michelle and Nicole explore various astronomical topics, including merger debris around a galaxy, metal-mixing in early stars, quasi-periodic eruptions in Ansky, relic galaxies, Mercury's magnetosphere, and…
In this episode, Michelle and Nicole explore various astronomical topics, including merger debris around a galaxy, metal-mixing in early stars, quasi-periodic eruptions in Ansky, relic galaxies, Mercury's magnetosphere, and…
Episode 21 – Mercury, chemistry and quasi periodic eruptions
In this episode, Michelle and Nicole explore various astronomical topics, including merger debris around a galaxy, metal-mixing in early stars, quasi-periodic eruptions in Ansky, relic galaxies, Mercury's magnetosphere, and second-generation stars in globular clusters. Tune in on Spotify, Apple Podcasts, or other platforms for more insights.
starxiv.com
October 12, 2025 at 9:36 AM
Episode 21 – Mercury, chemistry and quasi periodic eruptions
In this episode, Michelle and Nicole explore various astronomical topics, including merger debris around a galaxy, metal-mixing in early stars, quasi-periodic eruptions in Ansky, relic galaxies, Mercury's magnetosphere, and…
In this episode, Michelle and Nicole explore various astronomical topics, including merger debris around a galaxy, metal-mixing in early stars, quasi-periodic eruptions in Ansky, relic galaxies, Mercury's magnetosphere, and…
Nicole’s final paper discussed this new take on second-gen (G2) stars in globular clusters: maybe they weren’t born polluted… maybe they merged into it. Mergers of MS + HeWD binaries can produce G2-like stars with He and N enrichment — even in the field.
arxiv.org/abs/2509.15337 🔭☄️
arxiv.org/abs/2509.15337 🔭☄️
September 29, 2025 at 4:30 PM
Nicole’s final paper discussed this new take on second-gen (G2) stars in globular clusters: maybe they weren’t born polluted… maybe they merged into it. Mergers of MS + HeWD binaries can produce G2-like stars with He and N enrichment — even in the field.
arxiv.org/abs/2509.15337 🔭☄️
arxiv.org/abs/2509.15337 🔭☄️
Michelle's final paper takes us through BepiColombo's latest results on the magnetosphere of Mercury with data taken form 3 fly-bys over the nightside of the planet. Listen to learn more about the complex snap-backs and plasma flows of this little planet. 🔭 ☄️ arxiv.org/abs/2509.17872
September 29, 2025 at 4:20 PM
Michelle's final paper takes us through BepiColombo's latest results on the magnetosphere of Mercury with data taken form 3 fly-bys over the nightside of the planet. Listen to learn more about the complex snap-backs and plasma flows of this little planet. 🔭 ☄️ arxiv.org/abs/2509.17872
Nicole’s second paper looked at the fossil galaxy Mrk1216 — compact and untouched since z ≈ 2. Its hot gas is still α-enhanced, with [Mg/Fe] ≈ 0.37 and a flat Type Ia SN contribution out to large radii. All signs point to early, rapid star formation.
arxiv.org/abs/2509.14613 🔭☄️
arxiv.org/abs/2509.14613 🔭☄️
September 29, 2025 at 11:40 AM
Nicole’s second paper looked at the fossil galaxy Mrk1216 — compact and untouched since z ≈ 2. Its hot gas is still α-enhanced, with [Mg/Fe] ≈ 0.37 and a flat Type Ia SN contribution out to large radii. All signs point to early, rapid star formation.
arxiv.org/abs/2509.14613 🔭☄️
arxiv.org/abs/2509.14613 🔭☄️