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CYGTEVCXO - Cygnus TeV Source Chandra X-Ray Point Source Catalog

HEASARC
Archive

Overview

A 50 ks Chandra observation of the unidentified TeV source in Cygnus reported by the High Energy Gamma-Ray Astronomy (HEGRA) collaboration reveals no obvious diffuse X-ray counterpart. However, 240 pointlike X-ray sources are detected within or nearby the extended TeV J2032+4130 source region, of which at least 36 are massive stars and two may be radio emitters. That the HEGRA source is a composite, having as a counterpart the multiple pointlike X-ray sources that are observed, cannot be ruled out. Indeed, the distribution of pointlike X-ray sources appears nonuniform and concentrated broadly within the extent of the TeV source region. A hypothesis is offered for the origin of the very high energy gamma-ray emission in Cyg OB2 based on the local acceleration of TeV-range cosmic rays and the differential distribution of OB versus less massive stars in this association.

The region of TeV J2032+4130 was observed by Chandra on 2004 July 12 for a total effective exposure time of 48,728 seconds using the Advanced CCD Imaging Specrometer imaging array (ACIS-I). The observation was centered on J2000.0 coordinates (RA, Dec) = )20 32 07.0, +41 30 30). This table contains the list of the 240 pointlike sources which were detected in the ACIS-I data and their 2MASS near-IR counterparts, if any are found within 3" of the X-ray sources. 130 (54%) of the 240 X-ray sources have 2MASS counterparts within these error radii.


Catalog Bibcode

2006ApJ...643..238B

References

Deeper Chandra Follow-up of Cygnus TeV Source Perpetuates Mystery
    Butt Y., Drake J., Benaglia P., Combi J., Dame T., Miniati F., Romero G.
   <Astrophys. J., 643, 238-244 (2006)>
   =2006ApJ...643..238B

Provenance

This table was created by the HEASARC in February 2007 based on the electronic version of Table 1 from the above reference which was obtained from the ApJ website.

Parameters

Source_Number
A running source number for the X-ray source in order of increasing X-ray hardness ratio.

Name
The name for the X-ray source recommended by the CDS Dictionary of Nomenclature of Celestial Objects using the '[BDB2006]' prefix (for Butt, Drake, Benaglia, 2006) and the source number.

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

Dec
The Declination in the selected equinox of the Chandra X-ray source. This was given in J2000.0 equinox and to a typocal precision of 0.01 arcseconds in the original table.

LII
The Galactic Longitude of the Chandra X-ray source.

BII
THe Galactic Latitude of the Chandra X-ray source.

SNR
The signal-to-noise ratio of the Chandra X-ray source.

Hardness_Ratio
The (2-10 keV)/(0.5-2.0 keV) hardness ratio of the X-ray source. The fact that that values range from -1.41 (soft) to 0.943 (hard) implies that this is defined as the logarithm of the ratio of hard (2-8 keV) to soft (0.5-2.0 keV) counts, although this is not explicitly stated in the published reference.

Counts
The X-ray source counts.

RA_J2000_2MASS
The Right Ascension (J2000, sexagesimal) of the 2MASS counterpart to the Chandra X-ray source.

Dec_J2000_2MASS
The Declination (J2000, sexagesimal) of the 2MASS counterpart to the Chandra X-ray source.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 13-Feb-2007