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arXiv · 1110.0060

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
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Abstract

The Pan-STARRS1 survey has obtained multi-epoch imaging in five bands (Pan-STARRS1 gps, rps, ips, zps, and yps) on twelve "Medium Deep Fields", each of which spans a 3.3 degree circle. For the period between Apr 2009 and Apr 2011 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 6-sigma level, with a typical 1-sigma proper motion uncertainty of 10 mas/yr. We also used astrometry from SDSS (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 1-sigma uncertainty of 8 mas. Twelve of these candidates are known WDs, including the high proper motion (1.7"/yr) WD LHS 291. We confirm three more objects as WDs through optical spectroscopy. Based on the Pan-STARRS1 colors, ten of the stars are likely to be cool WDs with 4170 K Teff 5000 K and cooling ages <9 Gyr. We classify these objects as likely thick disk WDs based on their kinematics. Our current sample represents only a small fraction of the Pan-STARRS1 data. With continued coverage from the Medium Deep Field Survey and the 3pi survey, Pan-STARRS1 should find many more high proper motion WDs that are part of the old thick disk and halo.

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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. 2011-10-01. First Results from Pan-STARRS1: Faint, High Proper Motion White Dwarfs in the Medium-Deep Fields. https://doi.org/10.1088/0004-637x%2F745%2F1%2F42

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