First results from pan-starrs1: Faint, high proper motion white dwarfs in the medium-deep fields

J. L. Tonry*, C. W. Stubbs, M. Kilic, H. A. Flewelling, N. R. Deacon, R. Chornock, E. Berger, W. S. Burgett, K. C. Chambers, N. Kaiser, R. P. Kudritzki, K. W. Hodapp, E. A. Magnier, J. S. Morgan, P. A. Price, R. J. Wainscoat

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

The Pan-STARRS1 survey has obtained multi-epoch imaging in five bands (Pan-STARRS1 g P1, r P1, i P1, z P1, and y P1) on 12 "Medium-Deep fields," each of which spans a 33 circle. For the period between 2009 April and 2011 April these fields were observed 50-200 times. Using a reduced proper motion diagram, we have extracted a list of 47 white dwarf (WD) candidates whose Pan-STARRS1 astrometry indicates a non-zero proper motion at the 6σ level, with a typical 1σ proper motion uncertainty of 10 mas yr-1. We also used astrometry from the Sloan Digital Sky Survey (when available) and USNO-B to assess our proper motion fits. None of the WD candidates exhibits evidence of statistically significant parallaxes, with a typical 1σ uncertainty of 8 mas. Twelve of these candidates are known WDs, including the high proper motion (17 yr-1) WD LHS 291. We confirm seven more objects as WDs through optical spectroscopy. Based on the Pan-STARRS1 colors, ten of the stars are likely to be cool WDs with 4170K <T eff < 5000K and cooling ages 8Gyr. Based on their kinematics, these objects are likely thick disk WDs, but a subset may belong to the halo. Our current sample represents only a small fraction of the Pan-STARRS1 data. With continued coverage from the Medium-Deep Field Survey and the 3π survey, Pan-STARRS1 should find many more high proper motion WDs that are part of the old thick disk and halo.

Original languageEnglish (US)
Article number42
JournalAstrophysical Journal
Volume745
Issue number1
DOIs
StatePublished - Jan 20 2012
Externally publishedYes

Keywords

  • Galaxy: evolution
  • proper motions
  • surveys
  • white dwarfs

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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