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Submillimeter surveys of galaxy samples

Citation

Yang, Min (2007) Submillimeter surveys of galaxy samples. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-08012006-120712

Abstract

This thesis aims to gain a better understanding of dusty galaxies by studying the thermal emission of interstellar dust at submillimeter (submm) wavelengths. We conduct 350um observations of two galaxy samples selected based on entirely different criteria, using the Submillimeter High Angular Resolution Camera II (SHARC-II, Dowell et al. 2003) at the 10.4m Caltech Submillimeter Observatory (CSO). The first galaxy sample consists of 18 luminous infrared galaxies (LIGs) in the local Universe (0.003 <= z <= 0.042). We estimate the global properties in this galaxy sample; dust temperature (T_d = 38.6 ± 7.7 K), emissivity index (beta = 1.6 ± 0.3), far-infrared (FIR) luminosity (L_{fir} = 10^11.2±0.6 L_odot}) and dust mass (M_d = 10^7.4±0.6 M_odot$). Guided by theoretical considerations and laboratory measurements, we derive a T_d-beta inverse correlation for the local LIG sample; T_d = [5.03 imes 10^9]^1/4.46 + beta. The second galaxy sample consists of 36 ultraluminous infrared galaxies (ULIGs) at moderate redshifts (0.1 < z < 1.0), out of which 28 galaxies are detected. The newly acquired 350um data, in combination with the pre-existing IRAS 60um and 100um data, leads to meaningful estimates of the global properties in these galaxies for the first time; T_d = 40.9 ± 6.9K, L_{fir} = 10^12.2±0.5 L_odot$, M_d = 10^8.3±0.3 M_odot$ and intense starburst activity (SFR = 10^2.5±0.5 L_odot,yr^-1). There is strong circumstantial evidence that the T_d-beta inverse correlation observed in the local LIG sample remains valid in ULIGs at moderate redshifts. We find that the FIR-radio correlation observed in local star-forming galaxies continues to hold for ULIGs over the redshift range of 0.1 < z < 1.0 and dust heating originates predominantly from star formation. L_fir and T_d derived for dusty galaxy samples over a wide range of redshifts show significant scatter, due to differing selection biases and variations in dust mass and grain properties. We argue that the observed T_d, as a large-scale SED parameter, is linked to the global star formation efficiency (SFE) and the spatial extent characteristic of dominant star formation in a galaxy.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:galaxy; infrared; interstellar dust
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Phillips, Thomas G.
Group:Caltech Submillimeter Observatory
Thesis Committee:
  • Phillips, Thomas G. (chair)
  • Blain, Andrew W.
  • Soifer, B. Thomas
  • Zmuidzinas, Jonas
Defense Date:31 July 2006
Author Email:min (AT) submm.caltech.edu
Record Number:CaltechETD:etd-08012006-120712
Persistent URL:http://resolver.caltech.edu/CaltechETD:etd-08012006-120712
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5243
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:03 Aug 2006
Last Modified:16 Jul 2014 15:23

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