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Finding Needles in the Haystack: A Search for AM CVn Systems Using the Palomar Transient Factory


Levitan, David Benjamin (2013) Finding Needles in the Haystack: A Search for AM CVn Systems Using the Palomar Transient Factory. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/MJJ0-7A67.


The AM CVn systems are a rare class of ultra-compact astrophysical binaries. With orbital periods of under an hour and as short as five minutes, they are among the closest known binary star systems and their evolution has direct relevance to the type Ia supernova rate and the white dwarf binary population. However, their faint and rare nature has made population studies of these systems difficult and several studies have found conflicting results.

I undertook a survey for AM CVn systems using the Palomar Transient Factory (PTF) astrophysical synoptic survey by exploiting the "outbursts" these systems undergo. Such events result in an increase in luminosity by a factor of up to two-hundred and are detectable in time-domain photometric data of AM CVn systems. My search resulted in the discovery of eight new systems, over 20% of the current known population. More importantly, this search was done in a systematic fashion, which allows for a population study properly accounting for biases.

Apart from the discovery of new systems, I used the time-domain data from the PTF and other synoptic surveys to better understand the long-term behavior of these systems. This analysis of the photometric behavior of the majority of known AM CVn systems has shown changes in their behavior at longer time scales than have previously been observed. This has allowed me to find relationships between the outburst properties of an individual system and its orbital period.

Even more importantly, the systematically selected sample together with these properties have allowed me to conduct a population study of the AM CVn systems. I have shown that the latest published estimates of the AM CVn system population, a factor of fifty below theoretical estimates, are consistent with the sample of systems presented here. This is particularly noteworthy since my population study is most sensitive to a different orbital period regime than earlier surveys. This confirmation of the population density will allow the AM CVn systems population to be used in the study of other areas of astrophysics.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:AM CVn Systems;Cataclysmic Variables;Synoptic Surveys;White Dwarfs;Population Study;Spectroscopy;Optical;Astronomy;Palomar;Keck;Ultra-Compact Binaries;Photometry;Semi-Detached System;Dwarf Novae
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Prince, Thomas A.
Group:Astronomy Department
Thesis Committee:
  • Prince, Thomas A. (chair)
  • Kulkarni, Shrinivas R.
  • Phinney, E. Sterl
  • Readhead, Anthony C. S.
Defense Date:28 May 2013
Non-Caltech Author Email:david (AT)
Additional Information:Title in 2013 Commencement program varies: Finding Needles in the Haystack: A Search for AM CVn Systems with the Palomar Transient Factory
Projects:Palomar Transient Factory (PTF)
Record Number:CaltechTHESIS:06062013-224902992
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7857
Deposited By: David Levitan
Deposited On:07 Jun 2013 23:41
Last Modified:05 Nov 2021 22:48

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