Armengot, M., Gomez De Castro, A.I., 2019.



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 -- 1786 Angstroms) 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.

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).
Armengot, M., Gomez De Castro, A.I., 2019, "Signatures of diffuse interstellar gas in the Galaxy Evolution Explorer all sky survey", A&A, 631, A59. arXiv: 1907.08099



Map of the UBF index in the area surveyed by GALEX. Middle

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Location of the galactic dust clouds according to Dutra & Bicca 2002

The E(B–V) values from the catalog are color-coded. Bottom


Soft X-ray background measured by ROSAT (Snowden et al. 1995)