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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:3
UID:UW-Physics-Event-9618
DTSTART:20260506T190000Z
DTEND:20260506T210000Z
DTSTAMP:20260513T145058Z
LAST-MODIFIED:20260421T143602Z
LOCATION:Chamberlin 5280
SUMMARY:The Physical Properties and Redshifts of Dusty Star-forming Ga
 laxies: Observational Studies with ALMA and JWST\, Thesis Defense\, St
 ephen McKay
DESCRIPTION:Dusty star-forming galaxies (DSFGs) represent an extreme p
 hase of rapid dust-obscured galaxy assembly and are major contributors
  to the cosmic star-formation rate density (SFRD) at early times. For 
 some time\, a comprehensive understanding of the formation and evoluti
 on of DSFGs has been hindered by the difficulty of reliably identifyin
 g large\, deep samples and determining their redshifts and physical pr
 operties. In my thesis\, I present several studies using Atacama Large
  Millimeter/submillimeter Array (ALMA) and James Webb Space Telescope 
 (JWST) observations to characterize the DSFG population\, with a parti
 cular emphasis on the faint submillimeter population. First\, I use mu
 lti-band ALMA observations of 870 μm-selected DSFGs to model their du
 st spectral energy distributions (SEDs) to high precision\, showing th
 at the dust properties of sources at cosmic noon are generally consist
 ent with those seen in local galaxies and predicted by models. Using f
 ollow-up ALMA linescans along with ancillary JWST and ground-based red
 shifts for this sample\, I construct a nearly (97%) complete spectrosc
 opic redshift distribution for S850μm > 2 mJy DSFGs for the first tim
 e. The results illustrate the effectiveness of combining ALMA and JWST
  to measure DSFG redshifts\, and they demonstrate that JWST is particu
 larly effective at obtaining even high redshifts for DSFGs. However\, 
 the JWST coverage is just ~30% in the best-covered fields. I use these
  redshifts to test photometric redshift estimation methods and to cons
 train the shape of the DSFG redshift distribution.  Next\, I use ALMA 
 1.2 mm data to verify that a JWST NIR-color selection can determine ac
 curate positions for single-dish submillimeter (JCMT/SCUBA-2) sources\
 , including faint (S850μm < 2 mJy) DSFGs.  Using panchromatic SED fit
 s and surface brightness profile fitting\, I measure the physical prop
 erties and morphologies of these NIR-selected DSFGs\, finding that the
 y sit in a lower star-formation rate (SFR) regime (SFR ~ 50-150 Msun/y
 r) than that probed by typical single-dish 850 μm surveys. The stella
 r masses and morphologies of the bright (S850μm > 2 mJy) sources are 
 remarkably similar to those of the faint sources. Finally\, I observe 
 a low fraction of major mergers in constrast with previous studies bas
 ed on rest-frame optical wavelengths\, suggesting that these studies w
 ere impacted by severe dust attenuation. By helping to infer the prope
 rties of larger samples detected in future wide surveys\, these studie
 s will contribute to a precise mapping of the dust-obscured SFRD and s
 tructure assembly history of the Universe.
URL:https://www.physics.wisc.edu/events/?id=9618
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