Searching for the ghost of Lyman Alpha : a resonance line driving signature in the absorption troughs of broad absorption line quasars
Searching for the ghost of Lyman Alpha : a resonance line driving signature in the absorption troughs of broad absorption line quasars
Within this thesis I have searched the broad absorption line quasar (BALQSO) sample presented by Reichard and collaborators for objects exhibiting the so-called "ghost of Lyman alpha". This ghost manifests as a hump near -5900 km/s in the troughs of broad absorption lines and provides strong evidence for the importance of line driving in powering the outflows from BALQSOs. Of the 224 BALQSOs, selected by Reichard and collaborators, from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), 198 satisfy my redshift constraints, and 58 show clear evidence of multiple trough (MT) structure in their elY A1550A broad absorption line (BAL). A composite spectrum constructed from this MT sample already shows evidence for a ghost feature. Narrowing this classification scheme further, I define a set of 36 objects that individually show evidence of a ghost feature and then apply additional cuts to arrive at a final sample that contains my 7 strongest ghost candidates. Despite its limited size, this final sample triples the number of known BALQSOs with clear ghost signatures and should make an excellent basis for detailed follow-up studies. As a consequence of these initial results, I have developed an algorithm for the purpose of identifying BALQSOs within the latest SDSS Data Release 3 (DR3). This algorithm is designed to improve upon the SDSS determined redshifts and so enable the quick and accurate selection of BALQSOs exhibiting Ghost signatures. With the SDSS DR3 currently containing ~50,000 quasar spectra, this routine will likely uncover ~5,000-10,000 BALQSOs of which ~200-400 objects may well display the Ghost signature. This thesis details the algorithm and presents results from its testing phase. As an indication of its capabilities, I include herein the spectra of 5 new BALQSOs from the SDSS EDR, previously overlooked by Reichard.
University of Southampton
North, Matthew W. M
acab843d-9fdb-4ae3-b60f-b67423df3df2
2005
North, Matthew W. M
acab843d-9fdb-4ae3-b60f-b67423df3df2
North, Matthew W. M
(2005)
Searching for the ghost of Lyman Alpha : a resonance line driving signature in the absorption troughs of broad absorption line quasars.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Within this thesis I have searched the broad absorption line quasar (BALQSO) sample presented by Reichard and collaborators for objects exhibiting the so-called "ghost of Lyman alpha". This ghost manifests as a hump near -5900 km/s in the troughs of broad absorption lines and provides strong evidence for the importance of line driving in powering the outflows from BALQSOs. Of the 224 BALQSOs, selected by Reichard and collaborators, from the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR), 198 satisfy my redshift constraints, and 58 show clear evidence of multiple trough (MT) structure in their elY A1550A broad absorption line (BAL). A composite spectrum constructed from this MT sample already shows evidence for a ghost feature. Narrowing this classification scheme further, I define a set of 36 objects that individually show evidence of a ghost feature and then apply additional cuts to arrive at a final sample that contains my 7 strongest ghost candidates. Despite its limited size, this final sample triples the number of known BALQSOs with clear ghost signatures and should make an excellent basis for detailed follow-up studies. As a consequence of these initial results, I have developed an algorithm for the purpose of identifying BALQSOs within the latest SDSS Data Release 3 (DR3). This algorithm is designed to improve upon the SDSS determined redshifts and so enable the quick and accurate selection of BALQSOs exhibiting Ghost signatures. With the SDSS DR3 currently containing ~50,000 quasar spectra, this routine will likely uncover ~5,000-10,000 BALQSOs of which ~200-400 objects may well display the Ghost signature. This thesis details the algorithm and presents results from its testing phase. As an indication of its capabilities, I include herein the spectra of 5 new BALQSOs from the SDSS EDR, previously overlooked by Reichard.
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Published date: 2005
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Local EPrints ID: 465558
URI: http://eprints.soton.ac.uk/id/eprint/465558
PURE UUID: 6ff62124-96c2-40cc-9ecd-006201badcff
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Date deposited: 05 Jul 2022 01:45
Last modified: 16 Mar 2024 20:15
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Author:
Matthew W. M North
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