TRIFIDCXO - Trifid Nebula (M 20) Chandra X-Ray Point Source Catalog
This table contains a list of the Trifid Nebula (M 20) X-Ray point
sources detected by the Chandra X-ray Observatory (CXO) in an observation
carried out on 2002 June 13. The Trifid Nebula, a young star-forming H II
region, was observed for 16 hr by the Advanced CCD Imaging Spectrometer
imaging array, ACIS-I, detector. 304 X-ray sources were detected, 30% of
which are hard sources (defined as those sources having a 0.5-2.0 keV to
2.0-8.0 keV hardness ratio > -0.2) and 70% of which have near-infrared
Chandra observation of the Trifid nebula: X-ray emission from the O star
complex and actively forming pre-main-sequence stars.
Rho J., Ramirez S.V., Corcoran M.F., Hamaguchi K., Lefloch B.
<Astrophys. J., 607, 904-912 (2004)>
This table was created by the HEASARC in January 2007 based
on CDS table J/ApJ/607/904/table1.dat.
The X-ray source name using the prefix 'CXOM20 J' for Chandra X-ray
Observatory, the target (M 20), and the J2000 equatorial coordinates of
An alternative name for the X-ray source, using the prefix
'RRC2004 ' (Rho, Ramirez, Corcoran 2004) and the source number of the
An X-ray source number in order of increasing J2000
The preliminary source identification number
derived from the wavelet analysis tool (wavdetect). This was run using
an exposure map and it produced a catalog of 354 sources from the entire
ACIS-I 17' by 17' field of view (FOV). The authors then identified spurious
sources due to cosmic rays or to cases where the source counts were less
than the background counts, and rejected 50 of these sources, leading to
their final catalog of 304 sources contained in the present table.
The Right Ascension of the X-ray source in the selected equinox.
This was given in J2000 coordinates to a precision of 0.01 seconds of
time in the originating table.
The Declination of the X-ray source in the selected equinox.
This was given in J2000 coordinates to a precision of 0.1 arcseconds
in the originating table.
The Galactic Longitude of the X-ray source.
The Galactic Latitude of the X-ray source.
The net count rate in the 0.5-8.0 keV band of the X-ray
source, in counts per second, derived from the wavelet analysis.
The uncertainty in the X-ray source count rate, in
counts per second.
The signal-to-noise ratio of the X-ray source detection.
The X-ray source spectral hardness ratio HR between the
counts in the soft (0.5-2.0) keV and hard (2.0-8.0 keV) energy bands, S and
H, respectively, defined by the relation HR =(H-S)/(H+S).
The uncertainty in the X-ray spectral hardness
Questions regarding the TRIFIDCXO database table can be addressed to the
HEASARC User Hotline.
If you have any problems, please consult the help
page or mail email@example.com