white dwarfs

Five new outbursting AM CVn systems discovered by the Palomar Transient Factory

We present five new outbursting AM CVn systems and one candidate discovered as part of an ongoing search for such systems using the Palomar Transient Factory (PTF). This is the first large- area, systematic search for AM CVn systems using only large- …

The Frequency of Debris Disks at White Dwarfs

We present near- and mid-infrared photometry and spectroscopy from PAIRITEL, IRTF, and Spitzer of a metallicity-unbiased sample of 117 cool, hydrogen-atmosphere white dwarfs (WDs) from the Palomar-Green survey and find five with excess radiation in …

Three New Eclipsing White-dwarf-M-dwarf Binaries Discovered in a Search for Transiting Planets around M-dwarfs

We present three new eclipsing white-dwarf/M-dwarf binary systems discovered during a search for transiting planets around M-dwarfs. Unlike most known eclipsing systems of this type, the optical and infrared emission is dominated by the M-dwarf …

Calcium-rich Gap Transients in the Remote Outskirts of Galaxies

From the first two seasons of the Palomar Transient Factory, we identify three peculiar transients (PTF 09dav, PTF 10iuv, and PTF 11bij) with five distinguishing characteristics: peak luminosity in the gap between novae and supernovae (M$_R$ ≈ -15.5 …

PTF1 J071912.13+485834.0: An Outbursting AM CVn System Discovered by a Synoptic Survey

We present extensive photometric and spectroscopic observations of PTF1 J071912.13+485834.0, an outbursting AM CVn system discovered by the Palomar Transient Factory (PTF). AM CVn systems are stellar binaries with some of the smallest separations …

Rapidly Decaying Supernova 2010X: A Candidate ``.Ia'' Explosion

We present the discovery, photometric, and spectroscopic follow-up observations of SN 2010X (PTF 10bhp). This supernova decays exponentially with τ$_ d $ = 5 days and rivals the current recordholder in speed, SN 2002bj. SN 2010X peaks at M $_ r $ = …