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PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-7055
DTSTART:20220627T150000Z
DTEND:20220627T230000Z
DTSTAMP:20260414T224005Z
LAST-MODIFIED:20220623T164502Z
LOCATION:Sterling B343 and https://uwmadison.zoom.us/j/9932918764?pwd=
 dGhBTjUvKzBaNE9CKy81bEoyMktJUT09
SUMMARY:Extracting cosmological information from the sky\, from the co
 smic microwave background to intensity mapping with neutral hydrogen.\
 , Thesis Defense\, Anh Phan \, Physics PhD Graduate Student
DESCRIPTION:I will introduce several methods to extract cosmological i
 nformation from observations of the sky\, from the cosmic microwave ba
 ckground (CMB) to hydrogen line intensity mapping. Starting with the f
 irst light\, the CMB\, a cosmological Boltzmann code is presented to c
 alculate the CMB power spectra from different theoretical models\, for
  a flat $(\\Omega_k = 0)$ cosmology. It can rapidly compute the CMB po
 wer spectrum accurately up to high multipoles. After reviewing the chr
 onological evolution of the Universe\, I will then introduce the basic
  ideas of intensity mapping of neutral hydrogen after recombination\, 
 which tells us about structure formation. I will present the first res
 ults from the Tianlai Dish interferometer array\, which is a new instr
 ument specifically designed and constructed for hydrogen intensity map
 ping between redshift $z=0$ and $z=2.55$. The array is still in its in
 fancy\, and a thorough understanding of the instrument through simulat
 ion\, calibration\, noise analysis is described. An eigen-decompositio
 n method to remove the Sun signal from the timestream data of radio in
 terferometers is discussed in detail. It is applied to Tianlai data\, 
 which helps the instrument collect usable data during the daytime. Fin
 ally\, a machine learning method is presented that maximizes the cross
 -correlation between hydrogen intensity maps and galaxy redshift surve
 ys as a tool for detecting the hydrogen signal in the presence of brig
 ht foregrounds.
URL:https://www.physics.wisc.edu/events/?id=7055
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