Studies of the Links Between Quasar Black Hole Accretion and Star Formation in Their Host Galaxies: Data Analysis of the Herschel Astrophysical Terahertz Large Area Survey

Goodfellow, Mark Damian Dominic (2013). Studies of the Links Between Quasar Black Hole Accretion and Star Formation in Their Host Galaxies: Data Analysis of the Herschel Astrophysical Terahertz Large Area Survey. MPhil thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000f117

Abstract

The topic of this thesis is to gather evidence for a link between star formation in galaxies that contain a quasar in their nuclei. For quasars I argue that the best technique to measure the star formation rates is to use the far infrared.

I used the Herschel PACS 100 and 160 micron infrared data from the Herschel ATLAS programme to examine star formation rates in quasar host galaxies. I performed a stacking analysis of the PACS 100 and 160 micron data of a sample of 411 quasar candidates from the SDSS and 2SLAQ catalogues. The quasars are detected at up to 32σ, which I infer is from star formation in the galaxies that contain these quasars.

In order to obtain this data I have written a new timeline filtering subprogramme, plus a cross-scan filtering subprogramme, for the PACS data analysis pipeline. The outputs of this programme, using the early science phase Herschel data, were used to do the quasar stacking analysis.

I was also able to derive the formal minimuin-variance point source filter using the calculus of variations with undertermined Langrangian multiplers. This kernel optimises the signal to noise but leads to false positive signals. I opted to use a modified kernel that whitens the power spectrum of the noise, and gives us a more reliable point source detection. However, the SNR penalty, for different PACS pixels and data sets, lies in the range 30% to 40%.

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