Woo, Sui Chi
(2013)
CONSTRAINING THE GEOMETRY, SIZE SCALE AND PHYSICAL CONDITIONS OF OUTFLOWING BROAD ABSORPTION LINE REGIONS IN QUASARS.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Quasars are known for generating luminosities of up to 1047 erg/s in volumes of scales smaller than 2x10^15 cm. The optical/UV continuum emission is generally believed to
arise from a rotating accretion disk (AD) surrounding a supermassive black hole (SMBH) of ~10^8Msun. Such emission can be calculated by treating the AD as a multi-temperature blackbody. While the continuum emitting region is well defined, the properties, location and kinematics of the broad emission line regions (BELRs) and broad absorption line regions (BALRs) remain unclear. On one hand, the reverberation mapping technique can give constraints on the location of the BELRs, but not the kinematics. On the other hand, the line-of-sight kinematics of the BALRs is directly observable, but their locations are not well constrained, resulting in a large range of inferred distances, from 0.01 pc to tens of kpc. Therefore, I combined observational results to investigate the geometry, size, and physical conditions of the BELRs and BALRs. I verified that the Ly alpha and CIV BELRs are located at a similar distance. Using these findings, I was able to constrain the size of the Ly alpha BELR and place a lower limit on the size of the Nv BALR. I built an empirical model with the optical/UV continuum emission from the AD, the BELR from the chromosphere of the AD, and the outflowing BALR. In
the continuum region, I found that over 95 percent of the total flux comes from the region at ~125rg, where rg is the gravitational radius of the SMBH. For the BELRs, I computed a disk-wind model with relativistic effects to explain the often-observed single-peaked BEL profiles. However, I show that such a model cannot explain the observed blue asymmetries in the high-ionization BELs or their blueshifted peaks relative to low-ionization BELs. Using results on time variability of BALR gas, and assuming the variability is caused by the gas moving perpendicular across the line-of-sight over a time scale of about a year, I conclude that the BALR gas is clumpy or filamentary, with the clumps having a size scale of ~10^3 pc.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
24 July 2013 |
| Date Type: |
Publication |
| Defense Date: |
12 December 2012 |
| Approval Date: |
24 July 2013 |
| Submission Date: |
18 April 2013 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
146 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
BROAD ABSORPTION LINE REGIONS, BROAD EMISSION LINE REGIONS, QUASARS, REVERBERATION MAPPING, VARIABILITY |
| Date Deposited: |
24 Jul 2013 20:01 |
| Last Modified: |
15 Nov 2016 14:11 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/18475 |
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