J/A+A/631/A59 Fluctuations of UV background from GALEX (Armengot+, 2019)
Signatures of diffuse interstellar gas in the Galaxy Evolution Explorer
all sky survey.
Armengot M., Gomez de Castro A.I.
<Astron. Astrophys. 631, A59 (2019)>
=2019A&A...631A..59A 2019A&A...631A..59A (SIMBAD/NED BibCode)
ADC_Keywords: Interstellar medium ; Ultraviolet ; Diffuse clouds ;
Molecular clouds; Nebulae
Keywords: ultraviolet: ISM - methods: statistical - catalog - dust, extinction -
ISM: general
Abstract:
The all sky survey run by the Galaxy Evolution Explorer (GALEX AIS)
mapped about 85 % of the Galaxy at ultraviolet (UV) wavelengths and
detected the diffuse UV background produced by the scattering of the
radiation from OBA stars by interstellar dust grains. Against this
background, diffuse weak structures are detected as well as the UV
counterparts to nebulae and molecular clouds. To make full profit of
the survey, unsupervised and semi-supervised procedures need to be
implemented. The main objective of this work is to implement and
analyze the results of the method developed by us for the blind
detection of ISM features in the GALEX AIS. Most ISM features are
detected at very low signal levels (dark filaments, globules) against
the already faint UV background. We have defined an index the UV
background fluctuations index (or UBF index) to identify areas of the
sky where these fluctuations are detected. The algorithm is applied to
the images obtained in the FUV (1344-1786Å) band since this is less
polluted by stellar sources, facilitating the automated detection. The
UBF index is shown to be sensitive to the main star forming regions
within the Gould's Belt, as well as to some prominent loops like Loop
I or the Eridanus and Monogem areas. The catalogue with the UBF index
values is made available on-line to the community.
Description:
Catalog containing the Ultraviolet Background Fluctuations Index, as
described in the article, from the all sky survey run by the Galaxy
Evolution Explorer in the far ultraviolet (FUV) band (-intbgsub
files).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
ubfi.dat 66 66803 UBF index from GALEX/AIS FUV images
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Byte-by-byte Description of file: ubfi.dat
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Bytes Format Units Label Explanations
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1- 13 E13.8 deg GLON Galactic longitude of the center of the GALEX tile
15- 28 E14.8 deg GLAT Galactic latitude of the center of the GALEX tile
30- 42 E13.8 deg RAdeg Right Ascension of the center of the GALEX
tile (J2000)
44- 57 E14.8 deg DEdeg Declination of the center of the GALEX
tile (J2000)
59- 66 E8.3 --- UBFI Ultraviolet Background Fluctuations Index (1)
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Note (1): The UBF index has not units, it is computed from the rate of fluxes.
(see the article for more details).
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Acknowledgements:
Ana I. Gomez De Castro, aig(at)ucm.es
(End) Ana I. Gomez de Castro [UCM, Spain], Patricia Vannier [CDS] 12-Sep-2019