Theses and Dissertations

Date of Award

5-2020

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Physics

First Advisor

Dr. Mario C. Díaz

Second Advisor

Dr. Juan Madrid

Third Advisor

Dr. Nicolas Pereyra

Abstract

The era of multi-messenger astronomy has begun. The coordinated activities of multiple, distinct observatories play a critical role in both responding to astrophysical transients and building a more comprehensive interpretation otherwise inaccessible to individual observations. The Transient Robotic Observatory of the South (TOROS) Collaboration has a global network of instruments capable of responding to several transient targets of opportunity. The purpose of this thesis is to demonstrate how optical observatories with small fields of view (degree) can follow up and observe astrophysical transients. TOROS facilities responded to three unique gravitational wave events during the second and third observational campaigns of the Laser Interferometer Gravitational-Wave Observatory. We found no optical transients associated with the binary black hole merger GW170104 or the neutron star-black hole merger S190814bv. We detected the optical counterpart AT2017gfo during the follow-up response to the binary neutron star merger GW170817. Elliptical isophote modeling and subtraction of the host galaxy NGC 4993 reveal an isolated optical transient not seen in previous archival data. We performed relative time-series photometry in SDSS gri-bands on the detected transient. AT2017gfo exhibits rapid dimming in all bands and color change over the ~1.5 hours of time-series observations. We observe colors of AT2017gfo to be g-r = 0.79(0.08), r-i=0.23(0.08), and g-i=1.02(0.08) at ~35 hours post-merger. We calculate the corresponding absolute magnitudes Mg=-14.40(0.06), Mr=-15.06(0.05), and Mi=-15.22(0.06). We observe AT2017gfo to have an angular offset of ~10.4'' from the galactic core, corresponding to a linear diameter of ~2 kpc at redshift z=0.00973. Although AT2017gfo is generally recognized to be consistent with an r-process-powered thermal transient, or kilonova, our observations are in partial disagreement with the accepted picture. We address the plausible reasons for the discrepancies in our measurements. We developed a reduction and photometry pipeline during the processing and analysis of data from these events. The CTMO Analysis Pipeline (CAL) is currently at an early phase of operation, with plans for automation and further inclusion of additional analysis methods to optimize the TOROS search and characterization of astrophysical transients.

Comments

Copyright 2020 Richard Camuccio. All Rights Reserved.

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