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M51CXO - M 51 Chandra X-Ray Discrete Source Catalog

HEASARC
Archive

Overview

This table contains the results of two Chandra observations (separated by 1 year) of the population of X-ray sources in the spiral galaxy M 51 (NGC 5194 and NGC 5195). One hundred and thirteen X-ray sources have been detected in an 8.4' x 8.4'(20.4 x 20.4kpc) region, and 84 and 12 of them project within the disks of NGC 5194 and NGC 5195, respectively. Nine and 28 sources have luminosities exceeding 1 x 10^39 erg/s (ultraluminous X-ray sources or ULXs) and 1 x 10^38 erg/s in the 0.5 - 8 keV band, respectively, assuming that they are associated with M 51. The number of ULXs is much higher than found in most normal spiral and elliptical galaxies. Most of the X-ray sources and all seven of the ULXs in NGC 5194 are located in, or close to, a spiral arm, suggesting a connection with recent star formation.

The Chandra observations of M 51 were performed on 2000 June 20 and 2001 June 23 with the ACIS instrument. The background was stable in both observations, and effective exposure times of 14.9 and 26.8ks were obtained for the observations in 2000 and 2001, respectively.


Catalog Bibcode

2004ApJ...601..735T

References

The luminous X-ray source population in M51 observed with Chandra.
    Terashima Y., Wilson A.S.
   <Astrophys. J., 601, 735-758 (2004)>
   =2004ApJ...601..735T

Provenance

This table was created by the HEASARC in March 2007 based on CDS catalog J/ApJ/601/735 files table2.dat, table3.dat and table4.dat.

Parameters

Source_Number
A running number for the X-ray source in order of increasing J2000.0 Right Ascension in each of the original tables. Since this HEASARC table is formed from the concatenation of 3 tables from the reference paper, the source number by itself is not a unique source identifier. The combination of table number and source number, however, uniquely identifies an X-ray source in this table.

Table_Number
This HEASARC-created parameter indicates from which table the X-ray source was taken: a value of 2 indicates that it is one of the 84 sources spatially coincident with NGC 5194 listed in Table 2 of the reference paper, a value of 3 means it is one of the 12 sources spatially coincident with the companion galaxy NGC 5195 listed in Table 3, and a value of 4 means it is one of the 17 other sources elsewhere in the Chandra field listed in Table 4. The combination of table number and source number uniquely identifies an X-ray source in this table.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.01 seconds of time in the original tables.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Name
The name of the X-ray source using the 'CXOM51' prefix followed by the J2000.0 coordinates (JHHMMSS.s+DDMMSS), as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

Alt_Name
The alternate mame of the X-ray source using the '[TW2004]' prefix (from Terashima and Wilson 2004), followed by the string 'NGC 5194' for sources from Table 2 of the reference paper, or 'NGC 5195' for sources from Table 3, or 'Source' for sources from Table 4, and ending with the X-ray source number value, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects, e.g., '[TW2004] NGC 5194 1'.

FB_Counts
The observed counts for the X-ray source in the full (0.5 - 8 keV) band for the combined data set of the first and second observations. The number of counts has not been corrected for vignetting.

FB_Counts_Error
The RMS 1-sigma uncertainty in the full-band counts for the combined observation.

SB_Counts_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

SB_Counts
The observed counts for the X-ray source in the soft (0.5 - 2 keV) band for the combined data set of the first and second observations. The number of counts has not been corrected for vignetting.

SB_Counts_Error
The RMS 1-sigma uncertainty in the soft-band counts for the combined observation.

HB_Counts_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

HB_Counts
The observed counts for the X-ray source in the hard (2 - 8 keV) band for the combined data set of the first and second observations. The number of counts has not been corrected for vignetting.

HB_Counts_Error
The RMS 1-sigma uncertainty in the hard-band counts for the combined observation.

FB_Counts_Obs1_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

FB_Counts_Obs1
The observed counts for the X-ray source in the full (0.5 - 8 keV) band for the first observation. The number of counts has not been corrected for vignetting.

FB_Counts_Obs1_Error
The RMS 1-sigma uncertainty in the full-band counts for the first observation.

SB_Counts_Obs1_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

SB_Counts_Obs1
The observed counts for the X-ray source in the soft (0.5 - 2 keV) band for the first observation. The number of counts has not been corrected for vignetting.

SB_Counts_Obs1_Error
The RMS 1-sigma uncertainty in the soft-band counts for the first observation.

HB_Counts_Obs1_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

HB_Counts_Obs1
The observed counts for the X-ray source in the hard (2 - 8 keV) band for the first observation. The number of counts has not been corrected for vignetting.

HB_Counts_Obs1_Error
The RMS 1-sigma uncertainty in the hard-band counts for the first observation.

FB_Counts_Obs2_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection

FB_Counts_Obs2
The observed counts for the X-ray source in the full (0.5 - 8 keV) band for the second observation. The number of counts has not been corrected for vignetting.

FB_Counts_Obs2_Error
The RMS 1-sigma uncertainty in the full-band counts for the second observation.

SB_Counts_Obs2_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

SB_Counts_Obs2
The observed counts for the X-ray source in the soft (0.5 - 2 keV) band for the second observation. The number of counts has not been corrected for vignetting.

SB_Counts_Obs2_Error
The RMS 1-sigma uncertainty in the soft-band counts for the second observation.

HB_Counts_Obs2_Limit
This parameter is set to '<' if the value quoted in the associated counts parameter is an upper limit rather than a detection.

HB_Counts_Obs2
The observed counts for the X-ray source in the hard (2 - 8 keV) band for the second observation. The number of counts has not been corrected for vignetting.

HB_Counts_Obs2_Error
The RMS 1-sigma uncertainty in the hard-band counts for the second observation.


Contact Person

Questions regarding the M51CXO database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 4-Apr-2007