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.
<Astrophys. J., 724, 1389-1395 (2010)>
=2010ApJ...724.1389M 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: 1530Å and NUV: 2310Å) 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/cm2/s/sr/Å
and 433 photons/cm2/s/sr/Å 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/cm2/s/sr/Å/(MJy/sr) in the FUV band and that of
220 photons/cm2/s/sr/Å/(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: 1350-1750Å and
near-ultraviolet, NUV: 1750-2850Å). 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° field of view.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 45 31902 Diffuse flux observed by GALEX
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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
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Bytes Format Units Label Explanations
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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 (1530Å) (1)
39- 45 F7.2 10+5/m2/s/sr/nm NUV NUV band (2310Å) (1)
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Note (1): total fluxes include the airglow and zodiacal light.
In units of ph/cm2/s/sr/Angstrom.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 06-Aug-2012