Gas and Star Formation in Satellites of Milky Way Analogs

Jones, Michael G.; Sand, David J.; Karunakaran, Ananthan; Spekkens, Kristine; Oman, Kyle A.; Bennet, Paul; Besla, Gurtina; Crnojević, Denija; Cuillandre, Jean-Charles; Fielder, Catherine E.; Gwyn, Stephen; Mutlu-Pakdil, Burçin

Abstract

We have imaged the entirety of eight (plus one partial) Milky Way (MW)–like satellite systems, a total of 42 (45) satellites, from the Satellites Around Galactic Analogs II catalog in both Hα and H i with the Canada–France–Hawaii Telescope and the Jansky Very Large Array. In these eight systems we have identified four cases where a satellite appears to be currently undergoing ram pressure stripping (RPS) as its H i gas collides with the circumgalactic medium (CGM) of its host. We also see a clear suppression of gas fraction (M HI/M *) with decreasing (projected) satellite–host separation—to our knowledge, the first time this has been observed in a sample of MW-like systems. Comparisons to the Auriga, A Project Of Simulating The Local Environment, and TNG50 cosmological zoom-in simulations show consistent global behavior, but they systematically underpredict gas fractions across all satellites by roughly 0.5 dex. Using a simplistic RPS model, we estimate the average peak CGM density that satellites in these systems have encountered to be logρcgm/gcm−3≈−27.3 . Furthermore, we see tentative evidence that these satellites are following a specific star formation rate to gas fraction relation that is distinct from field galaxies. Finally, we detect one new gas-rich satellite in the UGC 903 system with an optical size and surface brightness meeting the standard criteria to be considered an ultra-diffuse galaxy.

Citation

Jones, M. G., Sand, D. J., Karunakaran, A., Spekkens, K., Oman, K. A., Bennet, P., …Mutlu-Pakdil, B. (2024). Gas and Star Formation in Satellites of Milky Way Analogs. Astrophysical Journal, 966(1), Article 93. https://doi.org/10.3847/1538-4357/ad3076

• Journal Article Type: Article
• Acceptance Date: Mar 4, 2024
• Online Publication Date: Apr 26, 2024
• Publication Date: May 1, 2024
• Deposit Date: Apr 29, 2024
• Publicly Available Date: Apr 29, 2024
• Journal: Astrophysical Journal
• Print ISSN: 0004-637X
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 966
• Issue: 1
• Article Number: 93
• DOI: https://doi.org/10.3847/1538-4357/ad3076
• Keywords: Circumgalactic medium, Galaxy quenching, Ram pressure stripped tails, Interstellar atomic gas, Dwarf galaxies
• Public URL: https://durham-repository.worktribe.com/output/2407443