EMSS (E0): Einstein X-ray Extended Medium Sensitivity Survey (19950117)
FILE: emss.e0 (835 sources)
CONTENTS: Einstein X-Ray Observatory Extended Medium Sensitivity Survey
DATASET: This file comes in HyperSky dataset E-13, version 19950117 Availability on HyperSky CD-ROM: Vol. 2 (1995)
DESCRIPTION: This datafile contains 835 X-ray sources detected with the Einstein X-Ray Observatory satllite's Extended Medium Sensitivity Survey (EMSS). The survey consists of serendipitous X-ray sources detected at or above 4 times the rms level in 1435 IPC fields with their centers located away from the galactic plane. Their limiting sensitivities range from ~5*10-14 to to ~ 3*10-12 ergs cm-2 s-1 in the 0.3-3.5keV band. A total area of 778 square degrees of the high galactic latitude sky (|b|>20) has been covered. The analysis has been performed using data from the Rev 1 processing system at the CfA (Center for Astrophysics at Cambridge).
The resulting EMSS catalog is a flux-limited and homogeneous sample of At present over 96% of the 835 X-ray sources have been successfully identified in the following proportions: active galactic nuclei (QSO's, quasars and Seyfert), 51.1%; BL Lacertae objects, 4.3%; clusters of galaxies, 12.2%; normal galaxies, 2.1%; cooling flow galaxies, 0.6%; Galactic stars 25.8%; and unidentified, 3.9%. Most of the individual optical counterparts are previously unknown objects and so constitute large statistical samples independent of previous selection methods.
The HyperSky file is based on the version of the catalog available from the U.S. National Space Sciences Data Center (NSSDC) as Astronomical Data Center (ADC) catalog #7152.
DATA: The HyperSky datafile contains the following data from the catalog:
POSITION: Right Ascension and Declination are based on the catalog 1950 positions, precessed to equinox 2000. Catalog positions were provided to an accuracy of 0.1 second in Right Ascension and 0.1" in declination.
MAG: The visual magnitude of the object found to be associated with the X-ray source.
IDENTIFICATION: The the source name; denoted by MS, followed by right ascension in hours, minutes, and truncated fraction of minutes, then declination in degrees and arcminutes (i.e. MS0013.4+1558).
COMMENTS: The comment lines following the identification contain the following information, where available, for each X-ray source:
* A line starting with "flux=", giving the X-ray flux (in units of 10E-13 erg/cm**2/s) in the 0.3-3.5 keV band. The flux has been computed in the 0.3-3.5 keV band for consistency with previous work. The authors provide a detailed discussion of assumptions and corrections relevant to this value in the catalog documentation.
* A line containing a brief description of the identified object type, based on the catalog typecode, followed by the object redshift (z) value if known. Possible type descriptions are:
active galaxy nucleus
galaxy cluster
cooling flow galaxy
BL Lac object
normal galaxy
star
unidentified source
* A line containing the comment "extended source", if the object is flagged as such in the catalog.
* A line containing any additional miscellaneous comments about the source, as provided in the comment columns of the catalog source entry. These comments have not been edited, except to reduce all multiple-blank sequences to single blanks.
REFERENCES
Gioia I.M., Maccacaro T., Schild R.E., Wolter A.: 1990 Astrophys. J. Suppl. Ser. 72, 567 ;
Stocke J.T., Morris S.L., Gioia I.M., Maccacaro T., Schild R.E., Wolter A., Fleming T.A., Henry J.P.: 1991 Astrophys. J. Suppl. Ser. 76, 813