SELHCGCXO - Selected Hickson Compact Groups Chandra X-Ray Point Source Catalog

Overview

This table contains the Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34 to 89 Mpc. The authors perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. They thus estimate X-ray luminosities (L_X) for all sources, most of which are too weak for reliable spectral fitting. For all sources, they provide counts, count rates, power-law indices (Gamma), hardness ratios, and L_X, in the full (0.5-8.0 keV), soft (0.5-2.0 keV) and hard (2-8 keV) bands. In their paper, the authors use optical emission-line ratios from the literature to re-classify 24 galaxies as star-forming, accreting onto a supermassive black hole (AGNs), transition objects, or low-ionization nuclear emission regions. Two-thirds of their galaxies have nuclear X-ray sources with Swift/UVOT counterparts. Two nuclei have full-band X-ray luminosities >= 10⁴² erg s^-1, are strong multi-wavelength AGNs, and follow the known alpha_OX - nu L_nu(near-UV)_ correlation for strong AGNs. Otherwise, most nuclei are X-ray faint, consistent with either a low-luminosity AGN or a nuclear X-ray binary population, and fall into the 'non-AGN' locus in alpha_OX - nu L_nu(near-UV)_ space, which also hosts other normal galaxies.

Each group was observed at the aim point of the back-illuminated S3 CCD of Chandra's Advanced CCD Imaging Spectrometer (ACIS), with the exception of HCG 90, which was observed with the ACIS-I array. The details of the 9 Chandra observations analyzed herein are given in Table 1 of the reference paper. The full details of the X-ray analysis and point source detection procedures are given in Section 3 of the reference paper.

Catalog Bibcode

2014ApJS..212....9T

References

A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN
Fraction but a Dearth of Strong AGNs.
      Tzanavaris P., Gallagher S.C., Hornschemeier A.E., Fedotov K.,
      Eracleous M., Brandt W.N., Desjardins T.D., Charlton J.C., Gronwall C.
     <Astrophys. J. Suppl. 212, 9 (2014)>
     =2014ApJS..212....9T

Provenance

This table was created by the HEASARC in June 2014 based on electronic versions of Tables 2 and 3 from the reference paper which were obtained from the ApJS web site. Some of the values for the name parameter in the HEASARC's implementation of this table were corrected in April 2018.

HEASARC Implementation

The HEASARC converted the count rates in the original tables, which were in ct/ks (although labeled therein as ct/s), into ct/s. The HEASARC added names for these X-ray sources based on the standard designation for an unregistered Chandra X-ray source, e.g., 'CXOU J223622.7+335844', for the X-ray source with the corresponding J2000.0 equatorial coordinates. Some other specific issues are:

(1) The HEASARC has retained the entry for the source 144 in HCG 92, which had zero values of RA and Dec in the original table 2, and given it null positional values in its version of this table.

(2) In the process of ingesting this table, the HEASARC also discovered that source 3 and 4 in HCG 31 are within 0.0001 degrees of each other and thus have the same name, 'CXOU J050118.4-041654'. The listed properties of these two sources do differ, so they have both been retained in this table, but it is not clear that source '31-4' is a real source.

Parameters

HCG_Name
The Hickson Compact Group (HCG) name, e.g., 'HCG 6'.

HCG_Galaxy_ID
A letter identifier for the galaxy in the Hickson Compact Group if the X-ray source lies within the field of an HCG galaxy, else this field is left blank.

Source_ID
A unique source identifier for each X-ray source in this catalog, e.g., '7-1' where the number before the hyphen is the HCG number and the number after the hyphen is a running source number in order of increasing J2000.0 RA within the field of the corresponding Chandra observation.

Nuclear_Flag
This flag parameter is set to 'Y' to indicates that the corresponding X-ray source is the nuclear source of the galaxy identified by the combination of the hcg_name and hcg_galaxy_id parameters, else is set to 'N'. In the reference paper, an asterisk was used to indicate that an X-ray source was a nuclear source.

Name
The standard designation for an unregistered Chandra X-ray source, e.g., 'CXOU J223622.7+335844', based on its J2000.0 equatorial coordinates. This parameter was created by the HEASARC.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-4 degrees (0.36 arcseconds) in the original table.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-4 degrees (0.36 arcseconds) in the original table.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Spectral_Index
The best-fit power-law spectral index (Gamma) to the X-ray spectrum of the X-ray source, where the photon flux is assumed proportional to E^_Gamma photon cm^-2 s^-1 keV^-1.

Spectral_Index_Pos_Err
The upper uncertainty to the best-fit power-law spectral index (Gamma) to the X-ray spectrum of the X-ray source.

Spectral_Index_Neg_Err
The lower uncertainty to the best-fit power-law spectral index (Gamma) to the X-ray spectrum of the X-ray source.

Log_FB_Flux
The logarithm of the full-band (0.5-8 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_FB_Flux_Error
The uncertainty in the logarithm of the full-band (0.5-8 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_SB_Flux
The logarithm of the soft-band (0.5-2.0 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_SB_Flux_Error
The uncertainty in the logarithm of the soft-band (0.5-2 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_HB_Flux
The logarithm of the hard-band (2-8 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_HB_Flux_Error
The uncertainty in the logarithm of the hard-band (2-8 keV) flux of the X-ray source, in erg cm^-2 s^-1.

Log_FB_Lx
The logarithm of the full-band (0.5-8 keV) luminosity of the X-ray source, in erg s^-1.

Log_SB_Lx
The logarithm of the soft-band (0.5-2.0 keV) luminosity of the X-ray source, in erg s^-1.

Log_HB_Lx
The logarithm of the hard-band (2-8 keV) luminosity of the X-ray source, in erg s^-1.

Log_2_keV_Flux
The logarithm of the flux density of the X-ray source at 2 keV, erg cm^-2 s^-1 Hz^-1.

Log_2_keV_Flux_Error
The uncertainty in the logarithm of the flux density of the X-ray source at 2 keV, erg cm^-2 s^-1 Hz^-1.

Hardness_Ratio_Det_Code
The hardness ratio detection code, as follows:

      0 = detection in both hard and soft bands;
     -1 = detection in hard but not soft band; HR is a lower limit;
      1 = detection in soft but not hard band; HR is an upper limit;
     -2 = no detection in either hard or soft band.

FB_Det_Code
The full-band detection code, as follows:

      0 = detection in band;
      1 = no detection in band because net counts < 0;
      5 = no detection in band because net counts - Gehrels 2-sigma error < 0.

SB_Det_Code
The soft-band detection code, as follows:

      0 = detection in band;
      1 = no detection in band because net counts < 0;
      5 = no detection in band because net counts - Gehrels 2-sigma error < 0.

HB_Det_Code
The hard-band detection code, as follows:

      0 = detection in band;
      1 = no detection in band because net counts < 0;
      5 = no detection in band because net counts - Gehrels 2-sigma error < 0.

PSF_Fraction
The encircled energy fraction of the X-ray source point spread function used by ACIS EXTRACT, at 1.5 keV.

FB_Counts
The number of counts in the X-ray source in the full band.

FB_Counts_Pos_Err
The upper uncertainty in the number of counts in the X-ray source in the full band.

FB_Counts_Neg_Err
The lower uncertainty in the number of counts in the X-ray source in the full band.

SB_Counts
The number of counts in the X-ray source in the soft band.

SB_Counts_Pos_Err
The upper uncertainty in the number of counts in the X-ray source in the soft band.

SB_Counts_Neg_Err
The lower uncertainty in the number of counts in the X-ray source in the soft band.

HB_Counts
The number of counts in the X-ray source in the hard band.

HB_Counts_Pos_Err
The upper uncertainty in the number of counts in the X-ray source in the hard band.

HB_Counts_Neg_Err
The lower uncertainty in the number of counts in the X-ray source in the hard band.

Hardness_Ratio
The hardness ratio HR of the X-ray source defined as HR = (H-S)/(H+S), where H and S represent the net counts for the source in the hard and soft bands, respectively.

Hardness_Ratio_Pos_Err
The upper uncertainty in the hardness ratio HR of the X-ray source defined as HR = (H-S)/(H+S).

Hardness_Ratio_Neg_Err
The lower uncertainty in the hardness ratio HR of the X-ray source defined as HR = (H-S)/(H+S).

FB_Count_Rate
The count rate in the full band (0.5-8 keV)of the X-ray source, in ct/s.

FB_Count_Rate_Pos_Err
The upper uncertainty in the count rate in the full band (0.5-8 keV)of the X-ray source, in ct/s.

FB_Count_Rate_Neg_Err
The lower uncertainty in the count rate in the full band (0.5-8 keV)of the X-ray source, in ct/s.

SB_Count_Rate
The count rate in the soft band (0.5-2.0 keV)of the X-ray source, in ct/s.

SB_Count_Rate_Pos_Err
The upper uncertainty in the count rate in the soft band (0.5-2.0 keV)of the X-ray source, in ct/s.

SB_Count_Rate_Neg_Err
The lower uncertainty in the count rate in the soft band (0.5-2.0 keV)of the X-ray source, in ct/s.

HB_Count_Rate
The count rate in the hard band (2-8 keV)of the X-ray source, in ct/s.

HB_Count_Rate_Pos_Err
The upper uncertainty in the count rate in the hard band (2-8 keV)of the X-ray source, in ct/s.

HB_Count_Rate_Neg_Err
The lower uncertainty in the count rate in the hard band (2-8 keV)of the X-ray source, in ct/s.

AE_Det_Significance
The AE (ACIS Extract) detection criterion of the X=ray source, namely the ae significance, which is essentially a traditional signal-to-noise criterion.

AE_No_Source_Prob
The AE (ACIS Extract) binomial probability, P_B, that the X-ray source is spurious (defined in Equation (4) of the reference paper; see Broos et al. 2010, ApJ, 714, 1582 for details).

Contact Person

Questions regarding the SELHCGCXO database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:34:48 EDT