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VERSION:2.0
PRODID:-//Heidelberg University//HePhySTO//EN
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTEND:20270128T111500Z
UID:0c93f86509bc70eeeff9c027b2939d6a@physik.uni-heidelberg.de
DTSTAMP:20261007T212953Z
LOCATION:ARI\, Moenchhofstrasse 12-14\, Seminarraum 1.OG
DESCRIPTION:The Dark Energy Spectroscopic Instrument (DESI) Data Release 1\
 , published in March 2025\, provides a lot of spectra of the ionized inters
 tellar medium in HII-regions within supposed dwarf galaxies.\nUsing the str
 ong line calibration method\, we derive their gas-phase oxygen abundance (1
 2+log(O/H))\, as a\nmetallicity indicator. Comparing these metallicities wi
 th stellar-mass estimates (CIGALE\, FASTSPECFIT)\,\nprovided by the DESI VA
 Cs\, we find that a "significant percentage" of the dwarf galaxies deviate 
 significantly from the mass-metallicity relation. We find that this is due 
 to deblending issues of extended galaxies in Legacy Survey (LS) data releas
 es - including DR9\, on which DESI DR1 photometry is based - leading to fau
 lty luminosities across all color bands in DESI DR1. This subsequently dist
 urbs mass estimates. Using segmentation maps applied to model images\, whic
 h we reconstruct from LS DR9 Tractor catalog data\, we estimate the luminos
 ities in different bands for over 3 million galaxies at z < 0.2. We find th
 at for a "significant percentage" of the galaxies our derived magnitudes ar
 e more than 1 mag brighter than DESI DR1 results.\nWith this corrected phot
 ometry\, genuine outliers from the mass-metallicity relation can now be obs
 erved.\n\nImported from https://www.physik.uni-heidelberg.de/hephysto/ (no 
 warranty for accuracy).
URL;VALUE=URI:https://www.physik.uni-heidelberg.de/hephysto/index.php?s=tal
 k&id=13017
SUMMARY:ARI Institute Colloquium: Victor Wichelhaus - Dwarf galaxies in DES
 I DR1: Deviation from the mass-metallicity relation or faulty photometry?
DTSTART:20270128T101500Z
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