J/ApJ/724/1389 Mapping the diffuse UV sky with GALEX (Murthy+, 2010) ================================================================================ Mapping the diffuse ultraviolet sky with the Galaxy Evolution Explorer. Murthy J., Henry R.C., Sujatha N.V. =2010ApJ...724.1389M ================================================================================ ADC_Keywords: Interstellar medium ; Surveys ; Ultraviolet Mission_Name: GALEX Keywords: diffuse radiation - dust, extinction - surveys - ultraviolet: ISM Abstract: We present a map of the diffuse ultraviolet cosmic background in two wavelength bands (FUV: 1530{AA} and NUV: 2310{AA}) over almost 75% of the sky using archival data from the Galaxy Evolution Explorer (GALEX) mission. Most of the diffuse flux is due to dust-scattered starlight and follows a cosecant law with slopes of 545 photons/cm^2^/s/sr/{AA} and 433 photons/cm^2^/s/sr/{AA} in the FUV and NUV bands, respectively. There is a strong correlation with the 100um Infrared Astronomy Satellite (IRAS) flux with an average UV/IR ratio of 300 photons/cm^2^/s/sr/{AA}/(MJy/sr) in the FUV band and that of 220 photons/cm^2^/s/sr/{AA}/(MJy/sr) in the NUV band but with significant variations over the sky. In addition to the large-scale distribution of the diffuse light, we note a number of individual features including bright spots around the hot stars Spica and Achernar. Description: The launch of the Galaxy Evolution Explorer (GALEX) in 2003 provided a new platform for diffuse UV observations. In the 7 years since its launch, GALEX has obtained over 30000 observations covering 75% of the sky in two ultraviolet bands (far-ultraviolet, FUV: 1350-1750{AA} and near-ultraviolet, NUV: 1750-2850{AA}). The GALEX instrument consists of a Ritchey-Chretien telescope with a diameter of 50cm for the primary mirror. Light from the sky is separated by a dichroic onto two detectors (FUV and NUV) with a spatial resolution of 3"-5" over a 1.25{deg} field of view. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 45 31902 Diffuse flux observed by GALEX -------------------------------------------------------------------------------- See also: II/114 : UV Interstellar Extinction (Savage+ 1985) J/ApJ/741/79 : The Spitzer-SDSS-GALEX Spectroscopic Survey (O'Dowd+, 2011) J/ApJ/718/L141 : FUV diffuse emission from the LMC (Pradhan+, 2010) J/A+AS/127/1 : 1997 reference of diffuse night sky brightness (Leinert+ 1998) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 F6.2 deg GLON Galactic longitude 8- 13 F6.2 deg GLAT Galactic latitude 15- 21 F7.2 10+5/m2/s/sr/nm TFUV Total FUV band flux (1) 23- 29 F7.2 10+5/m2/s/sr/nm TNUV Total NUV band flux (1) 31- 37 F7.2 10+5/m2/s/sr/nm FUV FUV band (1530{AA}) (1) 39- 45 F7.2 10+5/m2/s/sr/nm NUV NUV band (2310{AA}) (1) -------------------------------------------------------------------------------- Note (1): total fluxes include the airglow and zodiacal light. In units of ph/cm^2^/s/sr/Angstrom. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Aug-2012