"Peering Down the Barrel With DESI DR2: 10,000+ Inflows at z < 0.6"
ESO Lunch Talk
- Datum: 28.04.2026
- Uhrzeit: 12:00 - 12:45
- Vortragende(r): Simon Weng (Laboratoire d'Astrophysique de Marseille)
- Ort: ESO Garching
- Raum: Auditorium Telescopium
Abstract:
The depletion time of cold gas reservoirs in galaxies suggests that ongoing accretion is required to sustain star formation. However, direct detections of gas inflows have remained notoriously challenging. In this talk, I will present the detection of more than 50,000 Na I D down-the-barrel absorbers in galaxies at z < 0.6 from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2. I will discuss evidence for multiple pathways of accretion found in more than 10,000 galaxies, including radial inflows, gas recycling via fountains and mergers. I will then examine the stellar and morphological properties of galaxies hosting inflows and outflows. Finally, I will discuss the derivation of mass inflow and outflow rates from these measurements to understand whether ongoing accretion can sustain the star formation rate of galaxies at low redshift.
The depletion time of cold gas reservoirs in galaxies suggests that ongoing accretion is required to sustain star formation. However, direct detections of gas inflows have remained notoriously challenging. In this talk, I will present the detection of more than 50,000 Na I D down-the-barrel absorbers in galaxies at z < 0.6 from the Dark Energy Spectroscopic Instrument (DESI) Data Release 2. I will discuss evidence for multiple pathways of accretion found in more than 10,000 galaxies, including radial inflows, gas recycling via fountains and mergers. I will then examine the stellar and morphological properties of galaxies hosting inflows and outflows. Finally, I will discuss the derivation of mass inflow and outflow rates from these measurements to understand whether ongoing accretion can sustain the star formation rate of galaxies at low redshift.