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M67CXO - M 67 Chandra X-Ray Point Source Catalog |
HEASARC Archive |
This table summarizes the X-ray properties of the 158 sources which were detected by Chandra in this observation, and also lists the ROSAT (Belloni et al., 1998A&A...335..517B) and optical (candidate) counterparts.
A Chandra observation of the old open cluster M67. Van Den Berg M., Tagliaferri G., Belloni T., Verbunt F. <Astron. Astrophys., 418, 509-523 (2004)> =2004A&A...418..509V
Source_Number
A running source number, labelled as 'CX' for 'Chandra
X-ray (source)' in the original published table, in order of decreasing
counts (at least for the first 145 sources), i.e., source number 1
has the most counts (892), and source number 145 has only 3 counts.
Name
The X-ray source name based on the '[VTB2004] CX' prefix (for
Van den Berg, Tagliaferri, Belloni... 2004, Chandra X-ray) and the
source number, as recommended by the CDS Dictionary of Astronomical
Nomenclature.
Significance_Flag
An indicator of the significance of the X-ray
detection, where 'L' indicates that the source is detected with the
significance threshold set to 10-6 but not with the threshold set
to 10-7. A blank value indicates that that the source was detected
using both detection threshold values.
Off_Axis
The angular distance of the X-ray source from the telescope
aimpoint of (8 51 23.1, +11 49 32.7, J2000 RA and Dec), in arcminutes.
RA
The Right Ascension of the X-ray source in the selected equinox
derived from the image in the total (0.3 - 7 keV) energy band. The RA was
given in J2000.0 coordinates and to a precision of 0.001 seconds of time
in the original table. The X-ray positions have been corrected to the optical
reference frame by matching sources with EIS counterparts, resulting in
a final (X-ray - optical) offset correction to the RAs of -0.23" +/- 0.35".
RA_Error
The uncertainty in the Right Ascension of the X-ray source,
in seconds of time. The errors in RA and Declination are the 1-sigma
'wavdetect' errors, including the corrections for small count numbers
(See Section 2.3 of the paper for more details). These are often much
smaller than the uncertainty in the absolute positions, i.e. than the
uncertainty in the offset values in RA and Declination which are about
0.3 arcseconds.
Dec
The Declination of the X-ray source in the selected equinox derived
from the image in the total (0.3 - 7 keV) energy band. The Declination was
given in J2000.0 coordinates and to a precision of 0.01 arcseconds in the
original table. The X-ray positions have been corrected to the optical
reference frame by matching sources with EIS counterparts, resulting in a
final (X-ray - optical) offset correction to the Declinations of -0.20"
+/- 0.33".
Dec_Error
The uncertainty in the Declination of the X-ray source,
in arcseconds. The errors in RA and Declination are the 1-sigma
'wavdetect' errors, including the corrections for small count numbers
(See Section 2.3 of the paper for more details). These are often much
smaller than the uncertainty in the absolute positions, i.e. than the
uncertainty in the offset values in RA and Declination which are about
0.3 arcseconds.
LII
The Galactic Longitude of the X-ray source.
BII
The Galactic Latitude of the X-ray source.
Counts
The background-corrected counts in the X-ray source in the
total energy band (0.3 - 7 keV) as derived by wavdetect.
Counts_Error
The error in the background-corrected counts.
Count_Rate
The net (i.e., corrected for background counts and for
vignetting) count rate in the X-ray source in the total energy
band (0.3 - 7 keV), in counts per second.
Band_Flag
The energy band in which the X-ray source had the most
significant detection, according to the following codes:
'S' for the 0.3 - 2 keV (soft) band, 'H' for the 2 - 7 keV (hard) band,
and 'T' for the 0.3 - 7 keV (total) band.
Hardness_Ratio
The hardness ratio of the X-ray source, HR,
defined as (H'-S')/(H'+S') where S' and H' are the number of counts between
0.5 and 1 keV, and 1 and 7 keV, respectively, in the source region of the
detection in the total band, and are corrected for vignetting and background
counts. (Notice that these band definitions are different then those used in
the band_flag parameter). The hardness ratio is given only for sources for
which the error in the hardness ratio is less than 0.4. Sources with HR < 0
are considered to have soft spectra, while those with HR > 0 have hard
spectra. For sources with no counts between 0.5 and 1 keV, HR = 1.
Hardness_Ratio_Error
The uncertainty in the hardness ratio.
Belloni_Number
The candidate) ROSAT counterpart to the Chandra X-ray
source, using the source number NN from Belloni et al. (1998A&A...339..431B).
Such ROSAT sources are referred to as '[BVM98] M 67 NN' in Simbad.
Ctrpart_Name
The candidate optical counterpart to the Chandra X-ray
source, where the name of the counterpart was selected from (in order of
preference):
Prefix Reference S Sanders (1977A&AS...27...89S) E Momany et al. (2001A&A...379..436M) F Fan et al. (1996AJ....112..628F)Sources that were identified by eye by examining the EIS V-image to look for faint optical sources that are not included in these catalogs are labelled as 'faint', and their estimated optical positions are given in https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/418/509/table4.dat
Notes_Flag
This parameter has non-blank values from 'a' to 'f' to
indicate the existence of notes on individual sources in the file
https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/418/509/notes.dat
Offset
The offset, in arcseconds, between the Chandra X-ray source and
the proposed optical counterpart.