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The Landscape of Relativistic Stellar Explosions


Ho, Anna Yen Qin (2021) The Landscape of Relativistic Stellar Explosions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/99s8-vj17.


For the last half-century, relativistic outflows accompanying the final collapse of massive stars have predominantly been detected via high-energy emission (i.e., gamma-ray bursts, or GRBs). From wide-field optical and radio time-domain surveys, there have been hints of related phenomena at lower energies (e.g., X-ray flashes). For my thesis, I used the Zwicky Transient Facility to conduct the first large-scale optical survey dedicated to finding relativistic stellar explosions. I successfully detected a suite of GRB-related phenomena without relying on a GRB trigger, and followed them up with facilities across the electromagnetic spectrum including ALMA: relativistic afterglows at cosmological distances, broad-lined Ic (Ic-BL) supernovae with X-ray and radio emission, and fast-luminous transients powered by circumstellar interaction. Based on the rate of fast (intra-night) optical transients, I showed that a "clean" jet seems central to the phenomenon of collimated energetic outflows, i.e., there is no evidence for afterglow-like optical transients whose area (sky) rate greatly exceed the classical GRB rate. With a radio and millimeter-wave investigation of AT2018cow, and the discovery of a similar event in ZTF, I established a new class of engine-driven stellar explosions that arise from different progenitors to GRBs and explode embedded in dense circumstellar material. I showed that fast-luminous thermal emission can arise from late-stage eruptive mass-loss and is not necessarily linked to the presence of relativistic ejecta, complicating searches for choked jets in Ic-BL SNe. My work sets the stage for discovering and characterizing relativistic stellar explosions in large numbers during the era of ZTF Phase II, the Large Synoptic Survey Telescope (LSST), and millimeter-band facilities like ALMA and NOEMA.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Catalogs; gamma-ray burst: general; stars: activity; stars: flare; stars: jets; surveys; methods: observational; shock waves; stars: mass-loss; supernovae: individual; radio continuum: general; submillimeter: general; supernovae: general; X-rays: general; Radio transient sources; High energy astrophysics; Supernovae; Core-collapse supernovae; Jets; Sky surveys
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astrophysics
Awards:Rodger Doxsey Travel Prize of the American Astronomical Society, 2020. France A. Córdova Graduate Student Fund (Garmire Scholar), 2017.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Kulkarni, Shrinivas R.
Thesis Committee:
  • Steidel, Charles C. (chair)
  • Hallinan, Gregg W.
  • Kasliwal, Mansi M.
  • Perley, Daniel
  • Phinney, E. Sterl
  • Kulkarni, Shrinivas R.
Defense Date:2 July 2020
Non-Caltech Author Email:annayqho (AT)
Funding AgencyGrant Number
NSF Graduate Research Fellowship ProgramDGE-1144469
NSFPire Grant 1545949
Record Number:CaltechTHESIS:07132020-190219502
Persistent URL:
Related URLs:
URLURL TypeDescription adapted for Chapter 3. adapted for Chapter 2. adapted for Chapter 6. adapted for Chapter 5. adapted for Chapter 4. adapted for Chapter 7. adapted for Chapter 8.
Ho, Anna Yen Qin0000-0002-9017-3567
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13841
Deposited By: Anna Ho
Deposited On:24 Jul 2020 15:50
Last Modified:28 Oct 2021 16:33

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