These are my research projects from my astrophysics grad school and postdoc.
Constraining AGN Feedback in Massive Ellipticals with South Pole Telescope Measurements of the Thermal Sunyaev-Zel'dovich Effect
We observe that the characteristic masses of star-forming galaxies and the luminosities of
active galactic nuclei (AGN) have decreased in the past 10 billion years (since z~2)
[1,2],
which goes against the 'classic' model of structure formation where galaxies keep
getting larger over time [3].
One promising explanation for this observed 'downsizing'
is AGN feedback [4].
An AGN is a black hole in the center of a galaxy that is giving off
huge amounts of energy through emission from its accretion disk and radio jets
[5].
It could be possible for this energy to heat the galaxy up enough and blow out enough
matter to prevent further star formation and AGN accretion [4].
I am working with my advisor
Dr. Evan Scannapieco
(Website)
to try and measure this AGN feedback energy
using the thermal Sunyaev-Zel'dovich (tSZ) effect [6,7].
This effect happens when photons from the
Cosmic Microwave Background (CMB) get knocked up to higher energies when they pass
through hot ionized gas [7].
We are trying to select galaxies using the g, r, i, z, J, H, Ks bands from
the Blanco Cosmology Survey (BCS) and VISTA Hemisphere Survey (VHS) and then measure
the tSZ effect around these galaxies using data from the South Pole Telescope (SPT)
150 GHz and 220 GHz bands [8,9,10].
Last Update [3/8/2016]:
The paper has been published in the Astrophysical Journal!
arXiv paper [9.8 MB]
Searching For Fossil Evidence of AGN Feedback in WISE-Selected Stripe-82 Galaxies By Measuring the Thermal Sunyaev-Zel'dovich Effect With the Atacama Cosmology Telescope
This work is very similar to my previous work using SPT, but now using the Atacama Cosmology Telescope (ACT) to make
the tSZ measurements [11].
We now select galaxies using the Wide-field Infrared Survey Explorer (WISE) [12] and the Sloan Digital Sky Survey (SDSS) [13] and then measure
the tSZ effect around these galaxies using data from the ACT
148 GHz and 220 GHz bands.
Last Update [1/5/2017]:
The paper has been published in the Astrophysical Journal!
arXiv paper [3.7 MB]
Imaging Virgo A (M87) in the LOFAR High Frequency Bands
For this project I went to Germany for 7 weeks during the summer of 2013
with 3 other ASU students, and we worked with two postdocs there on Low Frequency Array (LOFAR) data.
LOFAR is an interferometric array
radio telescope covering a large area in Europe centered in the Netherlands
[14].
Since it was still fairly new in 2013 there was a lot of work being done to develop methods
of turning the raw data into detailed images. The work I did involved trying
to make an unprecedentedly detailed image of Virgo A using LOFAR's high band antennas
(120 - 240 MHz).
