GALEX catalogs of UV sources: statistical properties and sample science applications: hot white dwarfs in the Milky Way

Abstract

We describe the content and properties of UV source catalogs from GALEX's All-Sky Imaging Survey (AIS, 5σ depth ≈19.9(FUV)/20.8(NUV) mag, in the AB system) and Medium-depth Imaging Survey (MIS, 5σ depth ≈22.6(FUV)/22.7(NUV) mag), constructed by Bianchi L., et al.: Mon. Not. R. Astron. Soc. (2010, in press). The catalogs contain 65.3/12.6 million (AIS/MIS) unique UV sources with photometric error in NUV less than 0.5 mag, over 21 435(AIS)/1579(MIS) square degrees. Matched optical data from GSC-II provide additional B, R, I photometry for the brightest sources, and SDSS provides u g r i z photometry over 7325(AIS)/1103(MIS) square degrees overlap areas. We discuss statistical properties that are relevant for understanding sample selection biases and completeness, in potential science applications of these catalogs. The FUV (1344-1786 Å) and NUV (1771-2831 Å) photometry uniquely enable selection of the hottest stellar objects, in particular hot white dwarfs (WD), which are elusive at optical wavelengths because of their hot temperatures and faint luminosities. From the GALEX-SDSS matched sources we

HAT-P-67b: An Extremely Low Density Saturn Transiting an F-subgiant Confirmed via Doppler Tomography∗

“…While EUV or X-ray flux measurements do not exist, HAT-P-67 is identified as a source by GALEX, with flux measurements in the FUV (1344-1786 Å) and NUV (1771-2831 Å) bands. In Figure 13, we compile all transiting planet systems with GALEX FUV and NUV measurements (Bianchi et al 2011), as well as GAIA parallaxes and updated system parameters from . To examine the potential mass loss rate of HAT-P-67b in the context of existing systems, we plot the UV fluxes received by each planet (normalized to that received by HD 209458 b) against their escape velocities.…”

“…We plot the NUV left and FUV right fluxes received by known transiting systems against their escape velocities. Only systems with GALEX UV fluxes (Bianchi et al 2011) and GAIA parallaxes are plotted. As in Figure 11, the sizes of the points indicate their planetary radii, while the colors represent the equilibrium temperatures.…”

LACEwING: A New Moving Group Analysis Code

“…X-ray data were extracted from the ROSAT All-Sky Survey's bright star catalog (Voges et al 1999) and faint star catalog (Voges et al 2000) using an aperture of 25″ around all targets, after they were corrected by proper motion to their 1991 January 1 positions (the rough median date of the survey). Ultraviolet data from GALEX were extracted from the All-Sky Imaging Survey and Medium-Depth Imaging Survey (Bianchi et al 2011) after correcting all stars to their 2007 January 1 positions.…”

Broad-band spectral energy distribution of 3000 Å break quasars from the Sloan Digital Sky Survey

“…The VizieR Service at CDS Strasbourg 5 was used to extract the data from the SDSS Photometric Catalog, Release 7 (Abazajian et al 2009), the GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi et al 2011), and the UKIDSS-DR9 Large Area Surveys (Lawrence et al 2007). The NASA/IPAC Infrared Science Archive (IRSA) 6 was used to identify the SDSS sources in the 2MASS All-Sky Point Source Catalogue and in the AllWISE Source Catalog from WISE.…”