1209.1855 (Roger L. Griffith et al.)

Spitzer Photometry of WISE-Selected Brown Dwarf and Hyper-Luminous Infrared Galaxy Candidates    [PDF]

Roger L. Griffith, J. Davy Kirkpatrick, Peter R. M. Eisenhardt, Christopher R. Gelino, Michael C. Cushing, Dominic Benford, Andrew Blain, Carrie R. Bridge, Martin Cohen, Roc M. Cutri, Emilio Donoso, Thomas H. Jarrett, Carol Lonsdale, Gregory Mace, A. Mainzer, Ken Marsh, Deborah Padgett, Sara Petty, Michael E. Ressler, Michael F. Skrutskie, Spencer A. Stanford, Daniel Stern, Chao-Wei Tsai, Edward L. Wright, Jingwen Wu, Lin Yan

We present Spitzer 3.6 and 4.5 $\mu$m photometry and positions for a sample of 1510 brown dwarf candidates identified by the WISE all-sky survey. Of these, 166 have been spectroscopically classified as objects with spectral types M(1), L(7), T(146), and Y(12); Sixteen other objects are non-(sub)stellar in nature. The remainder are most likely distant L and T dwarfs lacking spectroscopic verification, other Y dwarf candidates still awaiting follow-up, and assorted other objects whose Spitzer photometry reveals them to be background sources. We present a catalog of Spitzer photometry for all astrophysical sources identified in these fields and use this catalog to identify 7 fainter (4.5 $\mu$m $\sim$ 17.0 mag) brown dwarf candidates, which are possibly wide-field companions to the original WISE sources. To test this hypothesis, we use a sample of 919 Spitzer observations around WISE-selected high-redshift hyper-luminous infrared galaxy (HyLIRG) candidates. For this control sample we find another 6 brown dwarf candidates, suggesting that the 7 companion candidates are not physically associated. In fact, only one of these 7 Spitzer brown dwarf candidates has a photometric distance estimate consistent with being a companion to the WISE brown dwarf candidate. Other than this there is no evidence for any widely separated ($>$ 20 AU) ultra-cool binaries. As an adjunct to this paper, we make available a source catalog of $\sim$ 7.33 $\times 10^5$ objects detected in all of these Spitzer follow-up fields for use by the astronomical community. The complete catalog includes the Spitzer 3.6 and 4.5 $\mu$m photometry, along with positionally matched $B$ and $R$ photometry from USNO-B; $J$, $H$, and $K_s$ photometry from 2MASS; and $W1$, $W2$, $W3$, and $W4$ photometry from the WISE all-sky catalog.

View original: http://arxiv.org/abs/1209.1855