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SUMMARY:Testing Baryonic Cycling: Star Formation\, Feedback\, Environment\
 , and Structure in Nearby Galaxies
DTSTART:20261014T060000Z
DTEND:20261014T070000Z
DTSTAMP:20261014T062900Z
UID:indico-event-5357@indico-tdli.sjtu.edu.cn
DESCRIPTION:Speakers: Hassen Yesuf\n\nTitle: Testing Baryonic Cycling: Sta
 r Formation\, Feedback\, Environment\, and Structure in Nearby GalaxiesTim
 e: 14:00-15:00 (UTC+8)\, 14 October 2026\, WednesdayHost: Darius Modirrous
 ta-GalianJoin Tencent Meeting：https://meeting.tencent.com/dm/ER304lTKMWn
 fMeeting ID: 450750540 (no password)\nAbstract:Galaxy evolution is governe
 d by processes spanning an enormous range of scales\, from supermassive bl
 ack hole growth and feedback to gas accretion\, star formation\, and dark 
 matter halo assembly. In this talk\, I test galaxy evolution models from t
 hree perspectives: galaxy populations\, internal structure\, and the baryo
 n cycle. First\, I highlight an analysis of ~60\,000 nearby active galacti
 c nuclei (AGNs)\, alongside new environmental and halo mass measurements f
 or AGN and non-AGN galaxies. Comparisons with the SIMBA\, IllustrisTNG\, a
 nd EAGLE simulations reveal major discrepancies in the connections among s
 tar formation\, black hole demographics\, environment\, and halo mass. The
  simulations overproduce quenched low-mass satellites in massive halos and
  fail to reproduce the quiescent fractions and AGN demographics of massive
  central galaxies and galaxies in low-density environments. Second\, I com
 pare Subaru HSC observations with mock images from the same simulations us
 ing a novel statistic\, structural abundance functions (SAFs)\, revealing 
 a “structural abundance crisis” across multiple galaxy structural indi
 ces. Finally\, I highlight new DESI results probing the baryon cycle throu
 gh spectroscopy of ~30\,000 galaxies. We identify cold gas inflows in ~20%
  and outflows in ~7% of galaxies. Surprisingly\, inflows are most common i
 n quiescent galaxies\, whereas star-forming galaxies are dominated by grav
 itationally bound outflows. Flow states are more strongly linked to stella
 r population age and recent evolutionary history than to present-day mass\
 , environment\, or structure. These findings suggest two regimes of baryon
 ic cycling: rapid outflow recycling through galactic fountains in star-for
 ming galaxies and persistent\, low-level “drizzling” inflows of metal-
 enriched gas in quiescent systems\, potentially sustained by halo cooling.
  Together\, these results reveal key tensions between observations and sim
 ulations and constrain the physical processes governing galaxy evolution.\
 nBiography:Hassen Yesuf is an Associate Researcher at the Shanghai Astrono
 mical Observatory\, CAS. He was a Kavli IPMU–KIAA Postdoctoral Fellow (2
 018–2023) and a postdoctoral researcher at the University of California\
 , Santa Cruz\, where he earned his PhD in Astrophysics and Statistics in 2
 016\, following a bachelor’s degree in Astrophysical Sciences from Princ
 eton University. His research aims to understand how galaxies evolve by co
 mbining large spectroscopic and imaging surveys\, advanced statistical and
  machine-learning methods\, and cosmological simulations to uncover the ph
 ysical processes driving galaxy evolution. His recent work focuses on the 
 spatiotemporal analysis of the baryon cycle in galaxies.\n\n\nhttps://indi
 co-tdli.sjtu.edu.cn/event/5357/
LOCATION:Tsung-Dao Lee Institute/S4F-SW - Open Area (Tsung-Dao Lee Institu
 te)
URL:https://indico-tdli.sjtu.edu.cn/event/5357/
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