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EUVEXRTCAT - All-Sky Catalog of Faint EUV Sources



The All-Sky Catalog of Faint Extreme-Ultraviolet (EUV) Sources is a list of 534 objects detected jointly in the Extreme Ultraviolet Explorer (EUVE) (100 Angstrom (AA) band) All-Sky Survey and in the ROSAT X-ray Telescope (XRT) (0.25 keV band) All-Sky Survey. The joint selection criterion within a 1.5 arcminute positional tolerance permitted the use of a low count rate threshold in each survey. This low threshold was roughly 60% of the threshold used in the previous EUVE all-sky surveys, and 166 of the objects listed in this table were new EUV sources, appearing neither in the Second EUVE Source Catalog nor in the ROSAT Wide Field Camera Second Catalog. Preliminary identifications are offered for 105 of the 166 sources not previously reported in any EUV catalog: by far the most numerous (81) of the identifications are late-type (F-M) stars, while 18 are other stellar types, only 5 are white dwarfs, and none are extragalactic. The paucity of WDs and extragalactic objects may be explained by a strong horizon effect wherein interstellar absorption strongly limits the effective new-source search volume, and, thereby, selectively favors low-luminosity nearby sources over more luminous but distant objects. Notice that, with the adopted 1.5 arcminute acceptance criterion, about 50 spurious detections are expected.

Catalog Bibcode



An all-sky catalog of faint extreme ultraviolet sources
    Lampton M., Lieu R., Schmitt J.H.M.M., Bowyer S., Voges W.,
    Lewis J., Wu X.
   <Astrophys. J., Suppl. Ser., 108, 545 (1997)>


This Browse table was created in July 2003 based on CDS table IX/35/faint.dat.

Mission Description

The Extreme Ultraviolet Explorer satellite was launched on June 7, 1992 from Cape Canaveral, Florida on a Delta II rocket. The payload contained three EUV scanning telescopes equipped with imaging detectors as well as a Deep Survey Spectrometer instrument which divided the light from a fourth telescope between an imaging detector and three EUV spectrometers.

The wavelength range covered was 100-600AA (10-60nm), corresponding to an energy range of 20-120eV, in the 4 bands:

      10nm : Lexan/Boron,  58-174{AA},  89{AA}peak
         DS: Lexan/Boron,  67-178{AA},  91{AA}peak (Deep Survey)
      20nm : Al/Ti/C,     156-234{AA}, 171{AA}peak
         DS: Al/C,        157-364{AA}, 171{AA}peak (Deep Survey)
      40nm : Ti/Sb/Ti/Al, 368-590{AA}, 405{AA}peak
      60nm : Sn/SiO,      519-742{AA}, 555{AA}peak

More details about the EUVE performances may be found in the paper by Sirk et al. (1997ApJS..110..347S).


The catalog designation for the EUVE source based on its J2000 position.

The Right Ascension of the X-ray source centroid location in the selected equinox. This was given in J2000 coordinates and to a precision of 1 second of time in the original table.

The Declination of the X-ray source centroid location in the selected equinox. This was given in J2000 coordinates and to a precision of 1 arcsecond in the original table.

The Galactic Longitude of the X-ray source.

The Galactic Latitude of the X-ray source.

The count rate in the EUVE 100AA band (which spanned from 70-130AA at 50% throughput), in counts/sec.

The count rate in the ROSAT X-Ray Telescope PSPC broad band (pulse heights between 0.1 and 2.4 keV), in counts/sec.

The angular separation between the EUVE and X-Ray source positions, in arcminutes.

A "plausible" optical, X-ray or EUV identification for the source. In addition to commonly used names and identifications such as HD numbers and variable star designations, catalogs cited for these identifications include:

        RE: Pounds et al., 1993, Cat. <J/MNRAS/260/77>
        1E: Giacconi et al., 1979ApJ...234L...1G
        4U: Forman et al., 1978ApJS...38..357F, Cat. <VII/18>
       TD1: Carnochan & Wilson, 1983MNRAS.202..317C (see also Cat. II/59)

This parameter contains flags which indicate the status of the object as an EUV source: "N" means it is a newly reported (EUV) object, "2" means that it is listed in the Second EUVE Source Catalog (Bowyer et al. 1996ApJS..102..129B), while "W" means that it is listed in the ROSAT WFC Catalog.

Contact Person

Questions regarding the EUVEXRTCAT database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 8-Nov-2004