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CHICAGOCXO - ChIcAGO Survey Chandra X-Ray Source Catalog

HEASARC
Archive

Overview

This table contains results from the 'Chasing the Identification of ASCA Galactic Objects' (ChIcAGO) survey, which is designed to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2-10 keV) within the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1. In ChIcAGO, the sub-arcsecond localization capabilities of Chandra have been combined with a detailed multi-wavelength follow-up program, with the ultimate goal of classifying the > 100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have been detected in these Chandra observations within 3 arcminutes of the original ASCA positions. The authors have identified infrared and optical counterparts to the majority of these sources, using both new observations and catalogs from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that emit in the X-ray flux range from ~ 10-13 to 10-11 erg cm-2 s-1 are active stellar coronae, massive stars with strong stellar winds that are possibly in colliding wind binaries, X-ray binaries, and magnetars. There is also another primary population that is still unidentified but, on the basis of its X-ray and infrared properties, likely comprises partly Galactic sources and partly active galactic nuclei.

A total of 93 AGPS sources have been observed with Chandra as part of the ChIcAGO survey, of which 84 were imaged with ACIS-S and 9 were imaged with HRC-I. The ChIcAGO Chandra observations took place over a 3.5 yr period, from 2007 January to 2010 July. The Chandra exposure times ranged from ~ 1 to 10 ks. All the details of these Chandra observations are listed in Table 1 of the reference paper. The initial automated analysis of these Chandra observations was conducted using the ChIcAGO Multi-wavelength Analysis Pipeline (MAP), described in Section 2.2 of the reference paper. ChIcAGO MAP takes the ACIS-S or HRC-I Chandra observation of an AGPS source field and detects and analyzes all point sources within 3 arcminutes, equivalent to the largest likely position error, for the original AGPS source positions supplied by Sugizaki et al. (2001, ApJS, 134, 77). The authors then performed a more detailed X-ray analysis and counterpart study for those 74 sources with > 20 X-ray counts, as such sources are approximately within the original AGPS sources X-ray flux range (see Sections 3.2 and 3.3 of the reference paper).

Infrared and optical follow-up were primarily performed on those ChIcAGO sources having > 20 X-ray counts. In order to determine which optical and infrared sources are counterparts to ChIcAGO sources, the authors used a technique similar to that described by Zhao et al. (2005, ApJS, 161, 429), using their Equation (11). If the separation between a ChIcAGO source's wavdetect position and its possible counterpart is less than the quadratic sum of their 3-sigma positional errors and the 3-sigma Chandra pointing error, then the X-ray and optical (or infrared) sources are likely to be associated. The 1-sigma positional errors for all sources in the 2MASS PSC and GLIMPSE catalogs are 0.1 arcseconds and 0.3 arcseconds, respectively. USNO B has an astrometric accuracy of < 0.25 arcseconds. The authors have assumed that the error distributions of the Chandra observations, Chandra pointing, and USNO B Catalog are all Gaussian for the purposes of identifying possible counterparts to the ChIcAGO sources.


Catalog Bibcode

2014ApJS..212...13A

References

Chasing the Identification of ASCA Galactic Objects (ChIcAGO) - An X-ray
Survey of Unidentified Sources in the Galactic Plane. I: Source Sample and
Initial Results.
    Anderson G.E., Gaensler B.M., Kaplan D.L., Slane P.O., Muno M.P.,
    Posselt B., Hong J., Murray S.S., Steeghs D.T.H., Brogan C.L.,
    Drake J.J., Farrell S.A., Benjamin R.A., Chakrabarty D., Drew J.E.,
    Finley J.P., Grindlay J.E., Lazio T.J.W., Lee J.C., Mauerhan J.C.,
    van Kerkwijk M.H.
   <Astrophys. J. Suppl. 212, 13 (2014)>
   =2014ApJS..212...13A

Provenance

This table was created by the HEASARC in June 2014 based on electronic versions of Tables 1, 2 and 12 from the reference paper which were obtained from the ApJS website.

HEASARC Implementation

The HEASARC has created this catalog from the contents of Table 1 (the list of ChIcAGO Chandra counterparts to the AGPS sources), Table 2 (the list of infrared properties of the Chandra source with > 20 X-ray counts) and Table 12 from the reference paper (the list of confirmed and tentative identifications of the AGPS sources, including both literature and ChIcAGO survey identifications), excluding the 76 sources in the last table which were not observed in the ChIcAGO survey. Thus, this present HEASARC table contains 259 entries: the 253 ChIcAGO Chandra possible counterparts to the AGPS sources and 6 entries for the 6 AGPS sources (AX J165951-4209, AX J175331-2538, AX J180816-2021, AX J183607-0756, AX J185905+0333 and AX J191046+0917) for which no ChIcAGO Chandra counterparts were found. These entries have been included herein with null positional values so they will not show up in any searches of this table based on position. They can be located by searching the table for sources with match_flag = 'N'.

Parameters

AGPS_Name
The source identifier for the ASCA Galactic Plane Survey (AGPS) X-ray source using the "AX' prefix (for ASCA X-ray source) and the J2000.0 equatorial coordinates truncated to 1 second of time in RA and 1 arcminute in Dec.

Match_Flag
This flag parameter indicates whether ('Y') or not ('N') the ASCA source was detected by Chandra in the ChIcAGO survey.

ObsID
The Chandra observation identification number (ObsID) of the ChIcAGO survey observation of the field of the AGPS source.

CXO_Date
The date of the Chandra observation.

CXO_Instrument
The Chandra instrument used (ACIS-S or HRC-I) in the Chandra observation.

Exposure
The exposure time of the Chandra observation, in seconds.

Name
The ChIcAGO Chandra X-ray source identifier. The naming convention which the authors have adopted is to call each Chandra source by the AGPS coordinate name, using ChI as the prefix, with a suffix between 1 and i, where i is equal to the number of sources detected in the 3-arcminute field. (The source name order is based on the order that wavdetect detected and output the sources in ChIcAGO MAP). For example, two ChIcAGO sources, ChI J165646-4239_1 and ChI J165646-4239_2, were detected with Chandra in the vicinity of the AGPS source AX J165646-4239.

Detect_Flag
This flag parameter has non-blank values of 'F' and 'G' which have the following significance:

      F = source has a probability of false detection that is > 1e-5
      G = source falls in the chip gap between ACIS-S CCDs 6 and 7.
  

RA
The Right Ascension of the ChIcAGO Chandra source as obtained from wavdetect. This was given in J2000.0 equatorial coordinates to a precision of 0.01 seconds of time in the original table.

Dec
The Declination of the ChIcAGO Chandra source as obtained from wavdetect. This was given in J2000.0 equatorial coordinates to a precision of 0.1 arcseconds in the original table.

LII
The Galactic Longitude of the ChIcAGO Chandra source.

BII
The Galactic Latitude of the ChIcAGO Chandra source.

CXO_Asca_Offset
The offset, in arcminutes, between the ChIcAGO source and the original AGPS source position as published in Sugizaki et al. (2001, ApJS, 134, 77).

Wav_Error_Radius
The 95% position error circle, in arcseconds, of the ChIcAGO source wavdetect position. This was calculated using Equation (5) of Hong et al. (2005, ApJ, 635, 907).

Error_Radius
The total 95% position error circle, in arcseconds, of the ChIcAGO source taking into account the wavdetect position error and the absolute astrometric accuracy of Chandra.

FB_Counts
The net number of counts in the 0.3-8 keV energy band detected from the ChIcAGO source. The source counts were calculated using a source region with a radius equal to 95% of the PSF at 1.5 keV. The total counts have been background subtracted.

FB_Counts_Neg_Err
The lower 1-sigma confidence limit for the net number of counts in the 0.3-8 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics.

FB_Counts_Pos_Err
The upper 1-sigma confidence limit for the net number of counts in the 0.3-8 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics.

SB_Counts
The net number of counts in the 0.5-2.0 keV energy band detected from the ChIcAGO source. The source counts were calculated using a source region with a radius equal to 95% of the PSF at 1.5 keV. The total counts have been background subtracted.

SB_Counts_Neg_Err
The lower 1-sigma confidence limit for the net number of counts in the 0.5-2.0 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics

SB_Counts_Pos_Err
The upper 1-sigma confidence limit for the net number of counts in the 0.5-2.0 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics.

HB_Counts
The net number of counts in the 2-8 keV energy band detected from the ChIcAGO source. The source counts were calculated using a source region with a radius equal to 95% of the PSF at 1.5 keV. The total counts have been background subtracted.

HB_Counts_Neg_Err
The lower 1-sigma confidence limit for the net number of counts in the 2-8 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics

HB_Counts_Pos_Err
The upper 1-sigma confidence limit for the net number of counts in the 2-8 keV energy band. This was calculated using Gehrels (1986, ApJ, 303, 336) statistics.

Phot_Energy_50pc
The energy E50, in keV, of the 50% photon detected in the 0.3 to 8 keV energy band. This values is used in the quantile analysis, the results for which are given in Tables 3 and 4 of the reference paper.

Phot_Energy_50pc_Error
The uncertainty in the energy E50, in keV, of the 50% photon detected in the 0.3 to 8 keV energy band

Quartile_Ratio
The quartile ratio, i.e., the ratio of the E25 (energy of the 25% photon detected) and E75 (energy of the 75% photon detected) used in the quantile analysis: 3 x (E25 - 0.3)/(E75 - 0.3). See Section 2.3.1 of the reference paper for further details.

Quartile_Ratio_Error
The uncertainty in the quartile ratio.

CSC_Name
The corresponding Chandra Source Catalog name for the ChIcAGO source (Evans et al. 2010, ApJS, 189, 37).

XMM_Name
The corresponding 2XMMi DR3 name for the ChIcAGO source (Watson et al. 2009, A&A, 493, 339).

NIR_Data_Codes
This parameter encodes information about the source for the near-infrared (NIR) data and/or the quality or other properties of the NIR counterpart to the ChIcAGO source. If three letters are listed, this indicates that the 3 magnitudes were obtained from different datasets. This order corresponds to the J, H and Ks magnitude order. Those datasets marked with a '*' are likely blended or, particularly in the case of the source ChI J194152+2251_2, perhaps extended. Those datasets marked with '**' mean that the counterpart has a low sigma detection of > 1.5 sigma for the respective background plus RMS estimate. The letter codes mean:

       M = 2MASS Point Source Catalog (Skrutskie et al. 2006, AJ, 131, 1163);
       P = PANIC Magellan observations (Section 2.4.1 of reference paper).
  

TwoMASS_Name
The 2MASS source identifier of the NIR counterpart to the ChIcAGO source. The wavdetect position of the source ChI J165646-4239_1 and the position of the quoted 2MASS source agree within 4 sigma. The authors have listed this 2MASS source as a possible counterpart as it is considered to be the same as the quoted GLIMPSE source, which does agree within 3 sigma of the wavdetect position. The quoted NIR magnitudes of the sources ChI J181116-1828_2 and ChI J185643+0220_2, obtained with PANIC, are limits due to the counterparts being blended. The H-band PANIC observation of the source ChI J194152+2251_2 took place on 2007-07-31, whereas the other bands were observed on 2007-07-29.

Jmag_Limit
This limit flag parameter is set to '>' if the quoted J-band magnitude of the NIR counterpart to the ChIcAGO source is an upper limit.

Jmag
The J-band magnitude of the NIR counterpart to the ChIcAGO source from the reference specified in the nir_data_codes parameter.

Jmag_Error
The uncertainty in the J-band magnitude of the NIR counterpart to the ChIcAGO source.

Hmag_Limit
This limit flag parameter is set to '>' if the quoted H-band magnitude of the NIR counterpart to the ChIcAGO source is an upper limit.

Hmag
The H-band magnitude of the NIR counterpart to the ChIcAGO source from the reference specified in the nir_data_codes parameter.

Hmag_Error
The uncertainty in the H-band magnitude of the NIR counterpart to the ChIcAGO source.

Ks_Mag_Limit
This limit flag parameter is set to '>' if the quoted Ks-band magnitude of the NIR counterpart to the ChIcAGO source is an upper limit.

Ks_Mag
The Ks-band magnitude of the NIR counterpart to the ChIcAGO source from the reference specified in the nir_data_codes parameter.

Ks_Mag_Error
The uncertainty in the Ks-band magnitude of the NIR counterpart to the ChIcAGO source.

PANIC_Date
The date of the PANIC observation of the counterpart to the ChIcAGO source.

GLIMPSE_Name
The GLIMPSE identifier of the NIR counterpart to the ChIcAGO source. Those magnitudes marked by a corresponding flag value of 'A' are from the GLIMPSE archives (more complete, less reliable) rather than from the catalogs (which are more reliable). In these former cases, the GLIMPSE archive sources names begin with the prefix 'SSTGLMA' for Spitzer Space Telescope Galactic Legacy infrared Mid-Plane survey Archive, while in the latter cases, they begin with the prefix 'SSTGLMC' for Spitzer Space Telescope Galactic Legacy infrared Mid-Plane survey Catalog. In both cases, the numerical part of the name corresponds to the galactic coordinates of the NIR counterpart.

IRAC_3p6_um_Mag
The GLIMPSE 3.6-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_3p6_um_Mag_Error
The uncertainty in the GLIMPSE 3.6-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_3p6_um_Mag_Flag
This flag parameter is set to 'A' to indicates that the corresponding Spitzer magnitude is obtained from the GLIMPSE archive rather than from a catalog.

IRAC_4p5_um_Mag
The GLIMPSE 4.5-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_4p5_um_Mag_Error
The uncertainty in the GLIMPSE 4.5-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_4p5_um_Mag_Flag
This flag parameter is set to 'A' to indicates that the corresponding Spitzer magnitude is obtained from the GLIMPSE archive rather than from a catalog.

IRAC_5p8_um_Mag
The GLIMPSE 5.8-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_5p8_um_Mag_Error
The uncertainty in the GLIMPSE 5.8-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_5p8_um_Mag_Flag
This flag parameter is set to 'A' to indicates that the corresponding Spitzer magnitude is obtained from the GLIMPSE archive rather than from a catalog. #

IRAC_8p0_um_Mag
The GLIMPSE 8.0-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_8p0_um_Mag_Error
The uncertainty in the GLIMPSE 8.0-micron band magnitude of the Spitzer counterpart to the ChIcAGO source.

IRAC_8p0_um_Mag_Flag
This flag parameter is set to 'A' to indicates that the corresponding Spitzer magnitude is obtained from the GLIMPSE archive rather than from a catalog.

Chicago_Matches
The equivalent ChIcAGO name of the AGPS source. All ChIcAGO sources with > 20 X-ray counts are listed. In a few cases, there is more than one ChIcAGO source listed for a given AGPS source. For a given identified H II region, all of the ChIcAGO sources contributed to the X-ray emission originally detected with ASCA in the AGPS. In these cases the ChIcAGO source name suffixes are listed in parentheses. If a suffix is listed before the parentheses then this ChIcAGO source corresponds to an X-ray source whose stellar type is listed in the source_type parameter, before the H II classification.

Source_Type
The source type abbreviations are as follows:

       ASC = active stellar corona;
       AGN = active galactic nucleus;
        CV = cataclysmic variable;
       CWB = colliding-wind binary;
      H II = young and massive stars in the H II region named in the alt_name
             parameter;
      HMXB = high-mass X-ray binary;
       LBV = luminous blue variable;
      LMXB = low-mass X-ray binary;
  Magnetar = magnetar;
        MS = massive star;
      MS-O = massive O-type star;
        ND = no ChIcAGO sources detected in the Chandra
             observation (no detection);
       PMS = pre-main sequence star;
       PSR = X-ray emission from a rotation-powered pulsar;
       PWN = pulsar wind nebula;
       SNR = supernova remnant;
      SyXB = symbiotic X-ray binary;
         U = unknown;
        WR = Wolf-Rayet star.
  
The other abbreviations are the spectral type of the stellar counterpart.

Alt_Name
The most commonly used name of the source.

Reference_Codes
This parameter contains the reference(s) for the identification of the AGPS counterpart coded as follows (the complete references are given in the bibliography of the reference paper):

        1 = This paper;
        2 = Sugizaki et al. (2001);
        3 = Skrutskie et al. (2006);
        4 = Anderson et al. (2011);
        5 = Degenaar et al. (2012);
        6 = Bernardini et al. (2011);
        7 = Israel et al. (2009);
        8 = Torres et al. (2006);
        9 = Tomsick et al. (2006);
       10 = Anderson et al. (2012);
       11 = Rodriguez et al. (2006);
       12 = Walter et al. (2006);
       13 = Naze et al. (2008);
       14 = Combi et al. (2006);
       15 = Bodaghee et al. (2006);
       16 = Funk et al. (2007);
       17 = Hamaguchi et al. (2005);
       18 = Kaur et al. (2010);
       19 = Markwardt et al. (2010);
       20 = Chakrabarty et al. (2002);
       21 = Combi et al. (2010);
       22 = Lazendic et al. (2005);
       23 = Gaensler et al. (2008);
       24 = Giacani et al. (2009);
       25 = De Becker et al. (2004);
       26 = Yamauchi et al. (2008);
       27 = Rho et al. (2004);
       28 = Mereghetti et al. (2005);
       29 = Israel et al. (2005);
       30 = Brogan et al.(2006);
       31 = Kargaltsev & Pavlov (2007);
       32 = Gotthelf & Halpern (2007);
       33 = Israel et al. (2004);
       34 = Mereghetti et al. (2012);
       35 = Helfand et al. (2003a);
       36 = Bassani et al. (2009);
       37 = Motch et al. (2010);
       38 = Kargaltsev et al. (2012);
       39 = Kaplan et al. (2007);
       40 = Gotthelf & Halpern (2008);
       41 = Paron et al. (2012);
       42 = Morii et al. (2003);
       43 = Bamba et al. (2001);
       44 = Helfand et al. (2003b);
       45 = Pooley et al. (2007);
       46 = Chen et al. (2004);
       47 = Yamaguchi et al. (2004);
       48 = Gotthelf & Halpern (2005);
       49 = Petre et al. (2002);
       50 = Yamauchi et al. (2011);
       51 = Safi-Harb et al. (2005);
       52 = Pavan et al. (2011);
       53 = Hwang et al. (2000);
       54 = Kohoutek & Wehmeyer (1997);
       55 = Zolotukhin & Chilingarian (2011).
  

Those archival AGPS sources and identified ChIcAGO sources that were used in the statistical analysis in Section 4.2 of the reference paper have two references in this parameter, the first being the paper describing an X-ray fit from which the authors derived an absorbed X-ray flux, and the second being the paper from which the NIR counterpart (J, H, and Ks magnitudes) information was obtained. All the longer-wavelength IR counterpart information (3.6, 4.5, 5.8, and 8.0 micron magnitudes) was gathered from the GLIMPSE catalogs and archives.

S2001_Flag
This flag parameter can contain 'C' and 'I' values which indicate those AGPS sources that were correctly and incorrectly identified by Sugizaki et al. (2001, ApJS, 134, 77), respectively.

ID_Flags
This parameter contains flags that correspond to the identification properties of the AGPS and ChIcAGO sources. One flag is listed for each of the following three properties: the AGPS source, the ChIcAGO identification and the source_type. The flag codes are as follows:

      I= Identified sources through work in the ChIcAGO survey;
      T = Tentatively identified sources using the X-ray and infrared population
          statistics in Section 4.2;
      F = AGPS sources for which only ChIcAGO sources with <= 20 X-ray counts
          were detected. These include AGPS sources where no sources were
          detected in the corresponding ChIcAGO Chandra observations but excludes
          those AGPS sources that have been identified as H II regions;
      R = Reference paper Figure 8 Region iv sources;
      N = Unconfirmed classification type;
      n = no flag.
  

Class
The HEASARC Browse object classification based on the value of the source_type parameter.


Contact Person

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

Page Author: Browse Software Development Team
Last Modified: 25-Jun-2014