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CYGTEVCXO: Help

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


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.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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