J/ApJ/734/13 GALEX ultraviolet halos around bright stars (Murthy+, 2011)
Dust-scattered ultraviolet halos around bright stars.
Murthy J., Henry R.C.
<Astrophys. J., 734, 13 (2011)>
=2011ApJ...734...13M 2011ApJ...734...13M
ADC_Keywords: Stars, early-type ; Ultraviolet ; Interstellar medium ; Extinction
Keywords: dust, extinction - ISM: clouds - ultraviolet: ISM
Abstract:
We have discovered ultraviolet (UV) halos extending as far as 5°
around four (of six) bright UV stars using data from the Galaxy
Evolution Explorer satellite. These halos are due to scattering of the
starlight from nearby thin, foreground dust clouds. We have placed
limits of 0.58±0.12 and 0.72±0.06 on the phase function asymmetry
factor (g) in the FUV (1521Å) and NUV (2320Å) bands,
respectively. We suggest that these halos are a common feature around
bright stars and may be used to explore the scattering function of
interstellar grains at small angles.
Description:
GALEX observed only 6 of the 50 brightest UV stars (table 1).
Most of these observations were part of the All-Sky Imaging Survey
with typical exposure times of about 100s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 6 Observation log
table3.dat 50 12795 GALEX FUV and NUV data around stars
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See also:
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
VI/110 : Final Merged Log of IUE Observations (NASA-ESA, 2000)
III/188 : IUE Atlas of B-Type Stellar Spectra (Walborn+ 1995)
III/86 : SKYLAB S-019 Far-UV Objective-Prism Spectrophotometry (Henize+ 1979)
II/59 : Catalogue of stellar UV fluxes (TD1) (Thompson+ 1978)
III/77 : Copernicus 0.2-A Resolution Far-UV Stellar Spectra (Snow+ 1977)
J/A+A/545/A130 : alpha Eri differential phases (Domiciano de Souza+, 2012)
J/ApJS/187/149 : StarCAT: STIS UV echelle spectra of stars (Ayres, 2010)
J/ApJS/126/461 : Equivalent Widths in the Spectrum of Sirius (Zhao+, 2000)
J/A+AS/105/305 : OB stars observed with high dispersion by IUE (Bohlin+ 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
10- 23 A14 --- AName Alternative name
24- 31 A8 --- SpT MK spectral type
33- 38 F6.2 deg GLON Galactic longitude
40- 45 F6.2 deg GLAT Galactic latitude
47- 51 F5.1 pc Dist Distance in pc to star
53- 56 F4.1 --- N(HI) HI column density to star (Shull & van Steenberg
1985ApJ...294..599S 1985ApJ...294..599S)
58- 61 I4 ct/s FUV Predicted GALEX FUV (1521Å) count rate
63- 66 I4 ct/s NUV Predicted GALEX NUV (2320Å) count rate
68- 69 I2 --- Nobs Number of observations within 5° of the star
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- Star Star name
10- 15 F6.2 deg GLON Galactic longitude
17- 22 F6.2 deg GLAT Galactic latitude
24- 28 F5.2 deg PA Angle from star
30- 36 F7.2 10+5/m2/s/sr/nm FUV-SB GALEX FUV band surface brightness (1)
38- 44 F7.2 10+5/m2/s/sr/nm NUV-SB GALEX NUV band surface brightness (1)
46- 50 F5.3 mag E(B-V) E(B-V)
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Note (1): In units of photons/cm2/s/sr/Angstrom.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Nov-2012