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ColemanKrawczyk

Ph.D. thesis, Coleman Krawczyk

In my thesis I made use of the standard aastex and emulateapj (including deluxetable) astro macros for latex. To get these to work with the drexel-thesis.cls I had to using the aastex_hack.sty included here. The yahapj.bst file makes it so the references are properly hyperlinked to their ads/arXiv pages.

In addition to my thesis I have also included my presentation slides. These were also made in latex (using beamer), and in them I made heavy use of tikz, a package that allows you to annotate basic shapes onto the slides. The commented \draw[help lines,xstep=.1,ystep=.1] (0,0) grid (1,1); lines will draw a series of grid lines on the slide to help with positioning.


Abstract

We explore the mid-infrared (mid-IR) through ultraviolet (UV) spectral energy distributions (SEDs) of 119,652 luminous type 1 quasars with 0.064 < z < 5.46 using mid-IR data from Spitzer and WISE, near-infrared data from 2MASS and UKIDSS, optical data from SDSS and UV data from GALEX. The mean SED requires a bolometric correction of BC = 2.75 ± 0.40 using the 2500 A integrated light from 1 μm–2 keV. We investigate the mean SED dependence on various parameters, particularly the UV luminosity for quasars with 0.5 <= z <= 3. Low-luminosity SEDs exhibit a bluer far-UV spectral slope, a redder optical continuum, and less hot dust. Our work suggests that lower-luminosity quasars may require an extra continuum component in the unseen extreme-UV that is weak in high-luminosity quasars. As such, we consider four possible models and explore the resulting BCs.

Taking a subset of ~35,000 uniformly selected quasars we explore their extinction/reddening in order to better understand their intrinsic SEDs. Using optical–UV photometry, we isolate outliers in the color distribution and find them well described by an SMC-like reddening law. A hierarchical Bayesian model was used to find distributions of power-law indices and E(B − V) consistent with both the broad absorption line (BAL) and non-BAL samples. 2.5% (13%) of the non-BAL (BAL) sample are shown to be consistent with E(B − V) > 0.1 and 0.1% (1.3%) with E(B − V) > 0.2. Simulations show both populations of quasars are intrinsically bluer than the mean composite, with a mean spectral index (αλ) of -1.79 (-1.83). The emission and absorption-line properties of both samples showed that quasars with intrinsically red continua have weaker Balmer lines and stronger ionizing spectral lines, the latter indicating a harder continuum in the extreme-UV.

Applying corrections for associated dust, we better determine the intrinsic SEDs and true BCs for our uniformly selected subsample. The SEDs with the most dust extinction are intrinsically brighter and showed more dust emission near ∼ 10 μm than the SEDs with less extinction. The bluer SEDs have more hot dust emission and higher BCs, consistent with having hotter accretions disks and/or being viewed closer to edge-on. Mean SEDs were also made based on the black hole mass (M BH) and the Eddington fraction (L/L Edd). Quasars with large L/L Edd and/or large M BH have more hot dust and a bluer optical continua, both consistent with a hotter accretion disk.