Astronomy Research

 

Graduate

My current research involves studying Active Galactic Nuclei (AGN) to understand how properties of supermassive black holes scale in relation to properties of their host galaxies.  The focus of my research is exploring the low-mass regime of the M-sigma relation by looking at a subclass of AGN known as Narrow Line Seyfert I galaxies, and in the process, learn more about this subclass of galaxies and how they can be used in the context of black hole demographics.

The majority of my research involves analyzing data from both the Hubble Space Telescope (HST), the Keck Telescopes atop Mauna Kea in Hawai’i, and the Sloan Digital Sky Survey (SDSS).

We have found that SMBHs are not growing as fast as previously thought, and that evolution of the M-sigma relation – if any – is marginal within the last six billion years.  You can read the paper here.

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The current M-sigma relation from Sexton et al. (2019).

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Surface-brightness Decompositions using GALFIT (Sexton et al. 2019).

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Multi-component spectral decomposition of spectra I have developed, in which all components are modeled simultaneously (Sexton et al. 2019).

Undergraduate

As part of my senior undergraduate thesis, I was fortunate enough to spend the 2012 summer at Steward Observatory in Tucson, Arizona as part of the California-Arizona Minority Partnership for Astronomy Research and Education (CAMPARE).  During this time I analyzed Spitzer imagery of the Carina Nebula, searching for stellar-wind bowshocks that may be the result of global feedback emanating from the central regions of the nebula (as opposed to local feedback from the host star).  We found that bowshock structures are indeed oriented toward the central regions of the Carina Nebula where powerful driving sources such as Tr 14 and Tr 16 are found, consistent with the idea of some global-feedback mechanism.  We also determined that these bowshock structures occupy a unique color space in Spitzer colors, consistent with resolved bowshock structures in M17 and RCW49.    These findings were eventually published in MNRAS in 2014.  Figures from the paper a shown below, and the paper itself can be found here.

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Spitzer MIPS false-color image of 24 um structures with clear bowshock morphologies (Red: MIPS 24 um, Green: IRAC 8 um, Blue: IRAC 3.6 um)

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Extended Red Objects (EROs) with 8 um bowshock morphologies occupy a unique Spitzer color space consistent with resolved bowshocks found in M17 and RCW49 (Povich et. al 2008).

I would like to thank Dr. Matthew Povich and Dr. Alexander Rudolph for all of their support during my undergraduate years a Cal Poly Pomona.