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ARCQUINCXO: Help

ARCQUINCXO - Arches and Quintuplet Clusters Chandra X-Ray Point Source Catalog


Overview

The Galactic centre (GC) provides a unique laboratory for a detailed examination of the interplay between massive star formation and the nuclear environment of our Galaxy. Here are presented some of the results from a 100-ks Chandra Advanced CCD Imaging Spectrometer (ACIS) observation of the Arches and Quintuplet star clusters in the form of a catalog of 244 point-like X-ray sources detected in the observation.

The deep Chandra ACIS-I observation (Obs. ID: 4500) was carried out on 2004 June 9. The Arches cluster was placed about 1-arcmin away from the aim point to minimize the effect of the CCD gaps on mapping the extended X-ray emission around the cluster.


Catalog Bibcode

2006MNRAS.371...38W

References

The interplay between star formation and the nuclear environment of our Galaxy:
deep X-ray observations of the Galactic centre Arches and Quintuplet clusters.
    Wang Q.D., Dong H., Lang C.
   <Mon. Not. R. Astron. Soc., 371, 38-54 (2006)>
   =2006MNRAS.371...38W    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in July 2007 based on CDS Catalog J/MNRAS/371/38 file table1.dat.

Parameters

Source_Number
A running X-ray source number in order of increasing J2000.0 Right Ascension for the first 235 sources which have individual local false detection probablilities P <= 10^-7). Sources 236 to 244 are the 9 sources found in the vicinity (2 x 3 square arcminutes) of the Arches and Quintuplet clusters for which a looser significance (10^-7 < P <= 10^-5) of being false was adopted.

Alt_Name
An alternative designation for the X-ray source using the '[WDL2006]' prefix (for Wang, Dong and Lang 2006) and the value of the source number parameter, as recommended by the CDS Dictionary of Nomenclature of Celestial Objects.

Source_Flag
This parameter is set to 'L' to indicate those sources (numbers 236 through 244 inclusive) found in the vicinity (2 x 3 square arcminutes) of the Arches and Quintuplet clusters for which a looser significance (10^-7 < P <= 10^-5) of being false was adopted.

Name
The preferred designation for the X-ray source using the 'CXOGCS' prefix (for Chandra X-Ray Observatory, Galactic Center Survey) and the J2000.0 coordinates (JHHMMSS.ss-DDMMSS.ss), as recommended by the CDS Dictionary of Nomenclature of Celestial Objects. Notice that in the reference paper, a slightly different (non-standard) prefix of 'CXGCS' was used.

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 table (implicitly in the name of the source).

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 (implicitly in the name of the source).

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Error_Radius
The positional uncertainty (1-sigma) of the X-ray source, in arcseconds, with the 1-sigma statistical error e calculated from the maximum-likelihood centroiding and an approximate off-axis angle-dependent systematic error E = 0.2" + 1.4"(r/8')^2, where r is the off-axis angle in arcminutes, added in quadrature (sqrt[e^2 + E^2]).

Count_Rate
The on-axis X-ray source broad-band count rate B in counts per second, i.e., the sum of the exposure-corrected count rates in the four energy bands S1 (1 - 2.5 keV), S2 (2.5 - 4.0 keV), H1 (4 - 6 keV), and H2 (6 - 9 keV). In addition, S = S1 + S2, H = H1 + H2 and B = S + H.

Count_Rate_Error
The RMS uncertainty in the on-axis X-ray source broad-band count rate, in counts per second.

Hardness_Ratio_1
The hardness ratio, HR1, defined as HR1 = (H - S2)/(H + S2) where the band count rates are defined above. This is listed only for sources which have HR1 values with uncertainties less than 0.2.

Hardness_Ratio_1_Error
The RMS uncertainty in HR1.

Hardness_Ratio_2
The hardness ratio, HR2, defined as HR2 = (H2 - H1)/(H) where the band count rates are defined above. This is listed only for sources which have HR2 values with uncertainties less than 0.2.

Hardness_Ratio_2_Error
The RMS uncertainty in HR2.

Detection_Bands
This parameter flags the bands in which a source was detected (B, S, and/or H). The band which generated the most accurate X-ray centroid position is listed first.


Contact Person

Questions regarding the ARCQUINCXO 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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