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M31PHATCXO - M 31 Disk Chandra PHAT Survey: X-Ray Source Catalog

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Overview

The X-ray source populations within galaxies are typically difficult to identify and classify with X-ray data alone. The authors break through this barrier by combining deep new Chandra ACIS-I observations with extensive Hubble Space Telescope (HST) imaging from the Panchromatic Hubble Andromeda Treasury (PHAT) of the M 31 disk. They detect 373 X-ray sources down to 0.35-8.0keV flux of 10-15erg/cm-2/s over 0.4deg2, 170 of which are reported for the first time. The authors identify optical counterpart candidates for 188 of the 373 sources, after using the HST data to correct the absolute astrometry of our Chandra imaging to 0.1". While 58 of these 188 are associated with point sources potentially in M 31, over half (107) of the counterpart candidates are extended background galaxies, 5 are star clusters, 12 are foreground stars, and 6 are supernova remnants. Sources with no clear counterpart candidate are most likely to be undetected background galaxies and low-mass X-ray binaries in M 31. The hardest sources in the 1-8keV band tend to be matched to background galaxies. The 58 point sources that are not consistent with foreground stars are bright enough that they could be high-mass stars in M 31; however, all but 8 have optical colors inconsistent with single stars, suggesting that many could be background galaxies or binary counterparts.

For point-like counterparts, the authors examine the star formation history of the surrounding stellar populations to look for a young component that could be associated with a high-mass X-ray binary. The associated star formation histories for sources in the catalog are available in the linked table M31PHATSFH.

In 2015 October, the authors observed the Panchromatic Hubble Andromeda Treasury (PHAT) footprint with Chandra with 7 pointings. The footprints are overlaid on a GALEX NUV image of M 31, along with the corresponding HST coverage, in Figure 1 of the reference paper. At each pointing they observed for about 50ks in VF mode (Chandra ObsID 17008 to 17014 spanning 2015 Oct 06 to 2015 Oct 26).


Catalog Bibcode

2018ApJS..239...13W

References

Comparing Chandra and Hubble in the northern disk of M31.
    Williams B.F., Lazzarini M., Plucinsky P.P., Sasaki M., Antoniou V.,
    Vulic N., Eracleous M., Long K.S., Binder B., Dalcanton J.J., Lewis A.R.,
    Weisz D.R.
   <Astrophys. J. Suppl. Ser., 239, 13-13 (2018)>
   =2018ApJS..239...13W

Provenance

This table was created by the HEASARC in April 2020 based upon the CDS Catalog J/ApJS/239/13 file table4.dat and table6.dat.

Parameters

Source_Number
The unique sequential identification number for each source in the catalog.

ObsID
The Chandra observation identifier (ObsID) for the dataset in which the source was measured.

Name
The catalog source designation, as registered by the CDS Dictionary of Nomenclature, e.g., in the form of '[WLP2018] CXO HHMMSS.ss+DDMMSS.s' where the HHMMSS.ss+DDMMSS.s are based on the sourcés right ascension and declination coordinates.

Alt_Name
The alternative source designation based on the source_number (NNN) and given by '[WLP2018] NNN' as registered by the CDS Dictionary of Nomenclature.

RA
The right ascension of the source, given in J2000.0 decimal degrees to a precision of 10-6 degrees in the originating table. These coordinates are based on the Chandra images, which were first astrometrically aligned using an initial source catalog of 26 sources with the PHAT imaging data (which have astrometric accuracy of ~10 milliarcsec), resulting in astrometric precision of better than 0.1 arcsec.

Dec
The declination of the source, given in J2000.0 decimal degrees to a precision of 10-6 degrees in the originating table. These coordinates are based on the Chandra images, which were first astrometrically aligned using an initial source catalog of 26 sources with the PHAT imaging data (which have astrometric accuracy of ~10 milliarcsec), resulting in astrometric precision of better than 0.1 arcsec.

LII
The galactic longitude of the source. This parameter has been added by the HEASARC and is derived from the J2000.0 source position.

BII
The galactic latitude of the source. This parameter has been added by the HEASARC and is derived from the J2000.0 source position.

Error_Radius
The Chandra X-ray positional uncertainty, in arcsec. The authors use the position uncertainty formula of Kim et al. 2004, ApJS, 150, 19.

Off_Axis
The off-axis angle in the Chandra observation, given in arcmin.

B1_Counts
The source net counts in the 0.35-8.0keV band.

B1_Counts_Neg_Err
The negative uncertainty for source net counts in the 0.35-8.0keV band.

B1_Counts_Pos_Err
The positive uncertainty for source net counts in the 0.35-8.0keV band.

B2_Counts_Limit
The limit flag for source net counts in the 0.35-1.0keV band, with "<" signifying an upper limit.

B2_Counts
The source net counts in the 0.35-1.0keV band. If the b2_counts_limit parameter is set to "<", then the b2_counts is the 1-sigma error provided by the acis_extract analysis.

B2_Counts_Neg_Err
The negative uncertainty for source net counts in the 0.35-1.0keV band.

B2_Counts_Pos_Err
The positive uncertainty for source net counts in the 0.35-1.0keV band.

B3_Counts
The source net counts in the 0.5-8.0keV band.

B3_Counts_Neg_Err
The negative uncertainty for source net counts in the 0.5-8.0keV band.

B3_Counts_Pos_Err
The positive uncertainty for source net counts in the 0.5-8.0keV band.

B4_Counts_Limit
The limit flag for source net counts in the 0.5-1.0keV band, with "<" signifying an upper limit.

B4_Counts
The source net counts in the 0.5-1.0keV band. If the b4_counts_limit parameter is set to "<", then the b4_counts is the 1-sigma error provided by the acis_extract analysis.

B4_Counts_Neg_Err
The negative uncertainty for source net counts in the 0.5-1.0keV band.

B4_Counts_Pos_Err
Positive Uncertainty for Source Net Counts in 0.5-1.0keV Band

B5_Counts_Limit
The limit flag for source net counts in the 1.0-2.0keV band, with "<" signifying an upper limit.

B5_Counts
The source net counts in the 1.0-2.0keV band. If the b5_counts_limit parameter is set to "<", then the b5_counts is the 1-sigma error provided by the acis_extract analysis.

B5_Counts_Neg_Err
The negative uncertainty for source net counts in the 1.0-2.0keV band.

B5_Counts_Pos_Err
The positive uncertainty for source net counts in the 1.0-2.0keV band.

B6_Counts_Limit
The limit flag for source net counts in the 2.0-4.0keV band, with "<" signifying an upper limit.

B6_Counts
The source net counts in the 2.0-4.0keV band. If the b6_counts_limit parameter is set to "<", then the b6_counts is the 1-sigma error provided by the acis_extract analysis.

B6_Counts_Neg_Err
The negative uncertainty for source net counts in the 2.0-4.0keV band.

B6_Counts_Pos_Err
The positive uncertainty for source net counts in the 2.0-4.0keV band.

B7_Counts_Limit
The limit flag for source net counts in the 2.0-8.0keV band, with "<" signifying an upper limit.

B7_Counts
The source net counts in the 2.0-8.0keV band. If the b7_counts_limit parameter is set to "<", then the b7_counts is the 1-sigma error provided by the acis_extract analysis.

B7_Counts_Neg_Err
The negative uncertainty for source net counts in the 2.0-8.0keV band.

B7_Counts_Pos_Err
The positive uncertainty for source net counts in the 2.0-8.0keV band.

B8_Counts_Limit
The limit flag for source net counts in the 4.0-8.0keV band, with "<" signifying an upper limit.

B8_Counts
The source net counts in the 4.0-8.0keV band. If the b8_counts_limit parameter is set to "<", then the b8_counts is the 1-sigma error provided by the acis_extract analysis.

B8_Counts_Neg_Err
The negative uncertainty for source net counts in the 4.0-8.0keV band.

B8_Counts_Pos_Err
The positive uncertainty for source net counts in the 4.0-8.0keV band.

B1_Count_Rate
The ARF-corrected count rate in the 0.35-8.0keV band.

B1_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 0.35-8.0keV band.

B1_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 0.35-8.0keV band.

B2_Count_Rate_Limit
The limit flag for source count rate in the 0.35-1.0keV band, with "<" signifying an upper limit.

B2_Count_Rate
The ARF-corrected count rate in the 0.35-1.0keV band. If the b2_count_rate_limit parameter is set to "<", then the b2_count_rate is the 1-sigma error provided by the acis_extract analysis.

B2_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 0.35-1.0keV band.

B2_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 0.35-1.0keV band.

B3_Count_Rate
The ARF-corrected count rate in the 0.5-8.0keV band.

B3_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 0.5-8.0keV band.

B3_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 0.5-8.0keV band.

B4_Count_Rate_Limit
The limit flag for source count rate in the 0.5-1.0keV band, with "<" signifying an upper limit.

B4_Count_Rate
The ARF-corrected count rate in the 0.5-1.0keV band. If the b4_count_rate_limit parameter is set to "<", then the b4_count_rate is the 1-sigma error provided by the acis_extract analysis.

B4_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 0.5-1.0keV band.

B4_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 0.5-1.0keV band.

B5_Count_Rate_Limit
The limit flag for source count rate in the 1.0-2.0keV band, with "<" signifying an upper limit.

B5_Count_Rate
The ARF-corrected count rate in the 1.0-2.0keV band. If the b5_count_rate_limit parameter is set to "<", then the b5_count_rate is the 1-sigma error provided by the acis_extract analysis.

B5_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 1.0-2.0keV band.

B5_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 1.0-2.0keV band.

B6_Count_Rate_Limit
The limit flag for source count rate in the 2.0-4.0keV band, with "<" signifying an upper limit.

B6_Count_Rate
The ARF-corrected count rate in the 2.0-4.0keV band. If the b6_count_rate_limit parameter is set to "<", then the b6_count_rate is the 1-sigma error provided by the acis_extract analysis.

B6_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 2.0-4.0keV band.

B6_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 2.0-4.0keV band.

B7_Count_Rate_Limit
The limit flag for source count rate in the 2.0-8.0keV band, with "<" signifying an upper limit.

B7_Count_Rate
The ARF-corrected count rate in the 2.0-8.0keV band. If the b7_count_rate_limit parameter is set to "<", then the b7_count_rate is the 1-sigma error provided by the acis_extract analysis.

B7_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 2.0-8.0keV band.

B7_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 2.0-8.0keV band.

B8_Count_Rate_Limit
The limit flag for source count rate in the 4.0-8.0keV band, with "<" signifying an upper limit.

B8_Count_Rate
The ARF-corrected count rate in the 4.0-8.0keV band. If the b8_count_rate_limit parameter is set to "<", then the b8_count_rate is the 1-sigma error provided by the acis_extract analysis.

B8_Count_Rate_Neg_Err
The negative uncertainty for the source count rate in the 4.0-8.0keV band.

B8_Count_Rate_Pos_Err
The positive uncertainty for the source count rate in the 4.0-8.0keV band.

Prob_No_Src
The probability (given as a %) that no source was detected at this location in the 0.35-8.0keV band.

B1_Flux
The energy flux in the 0.35-8.0keV band, in erg/s/cm2, calculated as the b1_count_rate * 1.313e-11.

B1_Flux_Neg_Err
The negative uncertainty for the energy flux in the 0.35-8.0keV band, calculated as the b1_count_rate_neg_err * 1.313e-11.

B1_Flux_Pos_Err
The positive uncertainty for the energy flux in the 0.35-8.0keV band, calculated as the b1_count_rate_pos_err * 1.313e-11.

B2_Flux_Limit
The limit flag for the energy flux in the 0.35-1.0keV band, with "<" signifying an upper limit.

B2_Flux
The energy flux in the 0.35-1.0keV band, in erg/s/cm2, calculated as the b2_count_rate * 1.767e-11. If the b2_flux_limit parameter is set to "<", then the b2_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B2_Flux_Neg_Err
The negative uncertainty for the energy flux in the 0.35-1.0keV band, calculated as the b2_count_rate_neg_err * 1.767e-11.

B2_Flux_Pos_Err
The positive uncertainty for the energy flux in the 0.35-1.0keV band, calculated as the b2_count_rate_pos_err * 1.767e-11.

B3_Flux
The energy flux in the 0.5-8.0keV band, in erg/s/cm2, calculated as the b3_count_rate * 1.272e-11.

B3_Flux_Neg_Err
The negative uncertainty for the energy flux in the 0.5-8.0keV band, calculated as the b3_count_rate_neg_err * 1.272e-11.

B3_Flux_Pos_Err
The positive uncertainty for the energy flux in the 0.5-8.0keV band, calculated as the b3_count_rate_pos_err * 1.272e-11.

B4_Flux_Limit
The limit flag for the energy flux in the 0.5-8.0keV band, with "<" signifying an upper limit.

B4_Flux
The energy flux in the 0.5-1.0keV band, in erg/s/cm2, calculated as the b4_count_rate * 1.438e-10. If the b4_flux_limit parameter is set to "<", then the b4_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B4_Flux_Neg_Err
The negative uncertainty for the energy flux in the 0.5-1.0keV band, calculated as the b4_count_rate_neg_err * 1.438e-10.

B4_Flux_Pos_Err
The positive uncertainty for the energy flux in the 0.5-1.0keV band, calculated as the b4_count_rate_pos_err * 1.438e-10.

B5_Flux_Limit
The limit flag for the energy flux in the 1.0-2.0keV band, with "<" signifying an upper limit.

B5_Flux
The energy flux in the 1.0-2.0keV band, in erg/s/cm2, calculated as the b5_count_rate * 5.620e-12. If the b5_flux_limit parameter is set to "<", then the b5_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B5_Flux_Neg_Err
The negative uncertainty for the energy flux in the 1.0-2.0keV band, calculated as the b5_count_rate_neg_err * 5.620e-12.

B5_Flux_Pos_Err
The positive uncertainty for the energy flux in the 1.0-2.0keV band, calculated as the b5_count_rate_pos_err * 5.620e-12.

B6_Flux_Limit
The limit flag for the energy flux in the 2.0-4.0keV band, with "<" signifying an upper limit.

B6_Flux
The energy flux in the 2.0-4.0keV band, in erg/s/cm2, calculated as the b6_count_rate * 1.443e-11. If the b6_flux_limit parameter is set to "<", then the b6_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B6_Flux_Neg_Err
The negative uncertainty for the energy flux in the 2.0-4.0keV band, calculated as the b6_count_rate_neg_err * 1.443e-11.

B6_Flux_Pos_Err
The positive uncertainty for the energy flux in the 2.0-4.0keV band, calculated as the b6_count_rate_pos_err * 1.443e-11.

B7_Flux_Limit
The limit flag for the energy flux in the 2.0-8.0keV band, with "<" signifying an upper limit.

B7_Flux
The energy flux in the 2.0-8.0keV band, in erg/s/cm2, calculated as the b7_count_rate * 2.138e-11. If the b7_flux_limit parameter is set to "<", then the b7_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B7_Flux_Neg_Err
The negative uncertainty for the energy flux in the 2.0-8.0keV band, calculated as the b7_count_rate_neg_err * 2.138e-11.

B7_Flux_Pos_Err
The positive uncertainty for the energy flux in the 2.0-8.0keV band, calculated as the b7_count_rate_pos_err * 2.138e-11.

B8_Flux_Limit
The limit flag for the energy flux in the 4.0-8.0keV band, with "<" signifying an upper limit.

B8_Flux
The energy flux in the 4.0-8.0keV band, in erg/s/cm2, calculated as the b8_count_rate * 3.487e-11. If the b8_flux_limit parameter is set to "<", then the b8_flux is measured from the 1-sigma error provided by the acis_extract analysis.

B8_Flux_Neg_Err
The negative uncertainty for the energy flux in the 4.0-8.0keV band, calculated as the b8_count_rate_neg_err * 3.487e-11.

B8_Flux_Pos_Err
The positive uncertainty for the energy flux in the 4.0-8.0keV band, calculated as the b8_count_rate_pos_err * 3.487e-11.

B9_Flux
The energy flux in the 0.2-4.5keV band, in erg/s/cm2, calculated as the b1_count_rate * 9.416e-12.

B9_Flux_Neg_Err
The negative uncertainty for the energy flux in the 0.2-4.5keV band, calculated as the b1_count_rate_neg_err * 9.416e-12.

B9_Flux_Pos_Err
The positive uncertainty for the energy flux in the 0.2-4.5keV band, calculated as the b1_count_rate_neg_err * 9.416e-12.

SPH2011_Source_Number
The matched XMM source identifier from Stiele+ 2011, J/A+A/534/A55 (linked to M31DEEPXMM).

Source_Type
The XMM source classification from Stiele+ 2011, J/A+A/534/A55 (refer to M31DEEPXMM), which uses the following schema:

               fg Star  = foreground star
              <fg Star> = foreground star candidate
              AGN       = active galactic nucleus
              <AGN>     = AGN candidate
              Gal       = galaxy
              <Gal>     = galaxy candidate
              GCl       = galaxy cluster
              <GCl>     = galaxy cluster candidate
              SSS       = supersoft source in M 31
              <SSS>     = supersoft source candidate in M 31
              SNR       = supernova remnant in M 31
              <SNR>     = supernova remnant candidate in M 31
              GlC       = source in globular cluster
              <GlC>     = source in globular cluster candidate
              XRB       = X-ray binary in M 31
              <XRB>     = X-ray binary candidate in M 31
              <hard>    = HR2-e_HR2>-0.2 or only HR3 and HR4 defined, and
                           no other classification
  

PHAT_Flag
The flag codes which indicate the PHAT optical counterpart type as follows:

              n = none (185 occurrences);
      	    g = galaxy (107 occurrences);
      	    p = point/star (58 occurrences);
      	    f = foreground (12 occurrences);
      	    s = SNR (6 occurrences);
      	    c = cluster (5 occurrences).
  

Vmag_Extinction
The mean V-band extinction based on maps from Dalcanton+ (2015ApJ...814....3D).

Notes
The notes from visual inspection of the PHAT images to identify optical counterparts are based on the selection process, described in Section 2.3 of the reference paper. The process included two people who searched the images and optical color magnitude diagrams independently and later compared their notes to converge on a final counterpart.

Source_Flag
The source flag that indicates the following information about the stellar counterpart candidates for the source in the PHAT survey:

  	    a = Included in the "best candidate" sample.
                  Note: CXO J004339.06+412117.6 is considered such a candidate,
                        but no SFH is available.
              c = No local young population detected.
  

Optical_RA
The HST PHAT right ascension, given in J2000.0 decimal degrees to a precision of 10-6 degrees in the originating table. The PHAT imaging data has astrometric accuracy of ~10 milliarcsec.

Optical_Dec
The HST PHAT declination, given in J2000.0 decimal degrees to a precision of 10-6 degrees in the originating table. The PHAT imaging data has astrometric accuracy of ~10 milliarcsec.

HST_F275W_Mag
The HST/WFC3 F275W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

HST_F336W_Mag
The HST/WFC3 F336W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

HST_F475W_Mag
The HST/ACS F475W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

HST_F814W_Mag
The HST/ACS F814W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

HST_F110W_Mag
The HST/WFC3 F110W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

HST_F160W_Mag
The HST/WFC3 F160W band magnitude based on the PHAT survey photometry (Dalcanton et al. 2012, ApJS, 200, 18; Williams et al. 2014, ApJS, 215, 9).

Class
The HEASARC Browse object classification of the X-ray source, based on the value of the source_type parameter (q.v.).


Contact Person

Questions regarding the M31PHATCXO database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Tuesday, 02-Jun-2020 14:58:41 EDT