Abstract/Details

Discovery and analysis of dust -reddened type 1 quasars - Finding the missing link in quasar evolution


2008 2008

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Abstract (summary)

One of the most important discoveries in recent times has been that the properties of the galaxies are proportional with the mass of the super-massive black hole in the center of the galaxy, which suggests that their growth was at some point linked.

In this thesis, I explore the population of dust-reddened broad lined quasars. These so-called red quasars might be the missing link in quasar evolution between quasars and starburst galaxies. As the two galaxies are merging, large columns of gas and dust from the hosts enshroud the quasar and provide feeding material for the starbursts. This would be an evolutionary step before becoming a blue quasar/elliptical galaxy system.

I describe how going after very red objects with radio counterparts, we are finding dust-reddened broad lined quasars with more than 50% success. At high redshifts, there is an unusually high fraction of Low Ionization Broad Absorption Line Quasars (LoBALs), a population which has often been invoked as being an early phase in the lifetime of a quasar. X-ray imaging and spectroscopy of a subsample of these red quasars have shown that they are all obscured, but not to the degree typically associated with torus obscuration. X-ray spectral indices also indicate high accretion efficiencies, a phenomenon associated with young quasars.

HST imaging of 13 of these dust-reddened quasars have found a large fraction (85%) of objects associated with major mergers showing tidal tails and double nuclei. None of the light profiles of the host galaxy fit an elliptical profile. This high interaction fraction is significantly higher than the typical 30% seen in host galaxies of blue quasars.

Furthermore, Spitzer observations show mid-infrared spectra that resemble the ones of Ultraluminous Infrared Galaxies (ULIRGs) for the quasars which show most interaction. ULIRGs are usually associated with extreme bursts of star formation. In the end, all of these clues confirm the thesis that red quasars are a young phase in the lifetime of a quasar.

Indexing (details)


Subject
Astronomy
Classification
0606: Astronomy
Identifier / keyword
Pure sciences; Dust-reddened; Galaxies; Quasars
Title
Discovery and analysis of dust -reddened type 1 quasars - Finding the missing link in quasar evolution
Author
Urrutia, Tanya Caroline
Number of pages
143
Publication year
2008
Degree date
2008
School code
0029
Source
DAI-B 69/09, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
ISBN
9780549830702
University/institution
University of California, Davis
University location
United States -- California
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3329678
ProQuest document ID
304646323
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/304646323
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