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MAXIGSC7YR - MAXI/GSC 7-Year High and Low Galactic Latitude Source Catalog (3MAXI)

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Overview

This table combines the published X-ray source catalogs of the high galactic latitude (|b| > 10o), Kawamuro et 2018, and the low galactic latitude (|b| < 10o), Hori et al. 2018, based on 7 years of MAXI Gas Slit Camera (GSC) data from 2009 August 13 to 2016 July 31.

The low galactic latitude catalog contains 221 sources with a significance threshold > 6.5 sigma. The low galactic faintest source has a flux of 5.2 x 10-12 erg cm-2 s-1 (or an intensity of 0.43 mCrab) in the 4-10 keV band. The high galactic latitude catalog contains 686 sources detected at significances >= 6.5 sigma in the 4-10 keV band. The high galactic 4-10 keV sensitivity reaches ~0.48 mCrab, or ~5.9 x 10-12 erg cm-2 s-1, over half of the survey area. The same data-screening criteria were applied to obtain the low and high galactic catalogs.

In their papers the authors describe the detection method, the statistical quantities derived for each source and their variability. To derive a counterpart, each source was cross-matched with the Swift/BAT 105-month catalog (BAT105; Oh et al. 2018), the Uhuru fourth catalog (4U; Forman et al. 1978), the RXTE All-Sky Monitor long-term observed source table (XTEASMLONG16), Meta-Catalog of X-Ray Detected Clusters of Galaxies (MCXC; Piffaretti et al. 2011), the XMM-Newton Slew Survey Catalog (XMMSL217), and the ROSAT All-Sky Survey Bright Source Catalog (1RXS; Voges et al. 1999). Seven of the sources in the low galactic latitudes were detected by binning the data differently (source numbers 215-221 in the catalog named 73-day sources), and, similarly, four of the sources in the high galactic latitude catalog named transient sources.

The parameters in the combined table include the source name (3MAXI), the position and its error, the detection significances and fluxes in the 4-10 keV, 3-4 keV bands and 10-20 keV bands the hardness ratios (HR1: 3-4 keV, 4-10 keV and HR2: 4-10 keV, 10-20 keV), excess variance in the 4-10 keV lightcurve and information on the likely counterpart. The high galactic catalogs also reports the flux in the 3-10 keV, an additional hardness (HR3: 3-10 keV and 10-20 keV) and an additional parameter representing variability. The hardness ratios are defined as H-S/H+S were S and H are the soft- and hard-band fluxes, respectively.

Catalog Bibcodes

2018ApJS..238...32K
2018ApJS..235....7H

References

The 7-year MAXI/GSC X-Ray Source Catalog in the High Galactic Latitude Sky (3MAXI)
     Kawamuro T., et al  <Astrophys. J. Suppl. 238, 33 (2018)>
    =2018ApJS..238...32K

The 7-year MAXI/GSC X-Ray Source Catalog in the Low Galactic Latitude Sky (3MAXI)
     Hori T., et al  <Astrophys. J. Suppl. 235,  (2018)>
    =2018ApJS..235....7H

Provenance

This table was created by the HEASARC in April 2021. It is a combination of the 7-year low- and high-latitude MAXI source catalogs published on ApJS. The data for the low-galactic latitude and the high-galactic latitude were downloaded from the ApJS electronic version of the Hori et al. 2018 ApJS 235,7 and Kawamuro et al. 2018 ApJS 238,33 papers respectively. The low-latitude data included in this table are from tables 4, 5, 6, 7 of the Hori paper that report the X-ray sources detected (214 sources, table 4), their possible identification (table 5), the transient sources discovered binning the data on 73 days period (7 sources, table 5) and their identification (table 6). The high-latitude data included in this table are from the tables 1,2,3 of the Kawamuro paper that report the X-ray sources detected (682 sources in table 1), their identifications (table 2), and the transient sources (4 sources in table 3). The low and high galactic latitude source catalogs provide for each individual source similar parameters for the X-ray properties with the high-latitude having three additional parameters, specifically, the flux in the 3-10 keV energy range, the 3-10/10-20-keV hardness ratio, and a time variability test. These parameters are kept in the HEASARC combined table and set to "blank" values for the low-latitude sources. The four sources in the high-latitude catalog named transient sources have only fluxes in the 4-10 keV band and no other fluxes in the other energy bands or the hardness ratio are reported. The HEASARC combined table includes a field to identify whether the source is from the low-latitude paper or the high-latitude paper and also maintains the source numbers that were published in the original catalogs.

Parameters

Name
The designated (3rd) MAXI 7-year catalog source name, based on its best-fit J2000.0 position and the '3MAXI' prefix for 3rd MAXI catalog, e.g., '3MAXI JHHMM+DDd'. The designation 'MAXI JHHMM+DDd' was used for sources in the (1st) MAXI 7-month catalog and '2MAXI JHHMM+DDd' in the 36-month catalog.

RA
The best-fit Right Ascension of the MAXI source in the selected equinox. This was given in J2000.0 decimal degrees in the original table..

Dec
The best-fit Declination of the MAXI source in the selected equinox. This was given in J2000.0 decimal degrees in the original table.

LII
The Galactic Longitude of the MAXI source.

BII
The Galactic Latitude of the MAXI source.

Error_Radius
The 1-sigma statistical position error of the MAXI source, in arcsec. To determine the cross-identification, the low-galactic latitude catalog uses an additional systematic error of 0.05 deg, the high-galactic latitude catalog uses an additional systematic error of 0.02 deg. Note: The error is not always reported for the low-galactic latitude sources.

Detsig_4_10
The detection significance of the MAXI GSC source in the 4-10 keV band. This is defined as (best fit 4-10 keV flux)/(its 1-sigma statistical error).

Flux_4_10
The MAXI/GSC flux in the 4-10 keV band, in erg s-1 cm-2, assuming a Crab like spectrum. The conversion factor from Crab units to erg s-1 cm-2 is 1 mCrab = 1.21 x 10-11 erg s-1 cm-2 in the 4-10 keV band.

Flux_4_10_Error
The 1-sigma statistical error in the MAXI/GSC source flux in the 4-10 keV band, in erg s-1 cm-2.

Detsig_3_4
The detection significance of the MAXI GSC source in the 3-4 keV band. NOTE: If the flux is an upper limit, the significance is set to 0.0 in the low-latitude catalog and to "blank" in the high-latitude catalog.

Flux_3_4_Limit
If populated, this indicates that the flux is an upper limit.

Flux_3_4
The MAXI/GSC flux in the 3-4 keV band, in erg s-1 cm-2, assuming a Crab like spectrum. The conversion factor from Crab units to erg s-1 cm-2 is 1 mCrab = 3.98 x 10-12 erg s-1 cm-2 in the 3-4 keV band. (Note in the Kawamuro paper the conversion factor is reported as 3.96 rather than 3.98)

Flux_3_4_Error
The 1-sigma statistical error in the MAXI/GSC source flux in the 3-4 keV band, in erg s-1 cm-2.

Detsig_10_20
The detection significance of the MAXI GSC source in the 3-4 keV band. NOTE: If the flux is an upper limit, the significance is set to 0.0 in the low-latitude catalog and to "blank" in the high-latitude catalog.

Flux_10_20_Limit
If populated, this indicates that the flux is an upper limit.

Flux_10_20
The MAXI/GSC flux in the 3-4 keV band, in erg s-1 cm-2, assuming a Crab like spectrum. The conversion factor from Crab units to erg s-1 cm-2 is 1 mCrab = 8.51 x 10-12 erg s-1 cm-2 in the 10-20 keV band.

Flux_10_20_Error
The 1-sigma statistical error in the MAXI/GSC source flux in the 10-20 keV band, in erg s-1 cm-2.

Flux_3_10
The MAXI/GSC flux in the 3-10keV band, in erg s-1 cm-2, assuming a Crab like spectrum. The conversion factor from Crab units to erg s-1 cm-2 is 1 mCrab = 1.61 x 10-11 erg s-1 cm-2 in the 3-10 keV band. Reported only for the high-latitude sources.

Flux_3_10_Error
The 1-sigma statistical error in the MAXI/GSC source flux in the 3-10 keV band, in erg s-1 cm-2. Reported only for the high-latitude sources.

Hardness_Ratio_1
The hardness ratio HR = (H-S)/(H+S), where H and S represent the observed fluxes in the 4-10 keV and 3-4 keV bands, respectively.

Hardness_Ratio_1_Error
The 1-sigma error in the hardness ratio HR1.

Hardness_Ratio_2
The hardness ratio HR = (H-S)/(H+S), where H and S represent the observed fluxes in the 10-20 and 4-10 keV bands, respectively.

Hardness_Ratio_2_Error
The 1-sigma error in the hardness ratio HR2.

Hardness_Ratio_3
The hardness ratio HR = (H-S)/(H+S), where H and S represent the observed fluxes in the 10-20 keV and 3-10 keV bands, respectively. Reported only for the high-latitude sources.

Hardness_Ratio_3_Error
The 1-sigma error in the hardness ratio HR3. Reported only for the high-latitude sources.

Timevar
Variability test applied to the lightcurves in the 4-10 keV band. The value is the result of the likelihood-based statistical method described in section 3.1 of Kawamuro et al.. The hypothesis that the flux does not vary can be ruled out for timevar > 18.48 at the 99% confidence level. Reported only for the high-latitude sources.

Excess_Variance
The excess variance normalized by the square of the mean flux (Vaughan et al. 2003 MNRAS 345 1271). The excess variance is calculated using the 4-10 keV lightcurves.

Excess_Variance_Error
The 1-sigma error in the excess variance.

Catalog
The parameter reports if the source is from the "low" galactic latitude catalog or from the "high" galactic latitude catalog.

Catalog_Source_Number
The parameter reports the source number as published in the low galactic and high galactic papers. This value is not unique by itself, but the combination of the catalog parameter and this parameter together uniquely identify each entry in this combined catalog.

Ctrpart_Name
The designation of the counterpart to the MAXI/GSC source.

Ctrpart_RA
The Right Ascension of the counterpart to the MAXI/GSC source provided in J2000.0 decimal degree coordinates in the catalogs.

Ctrpart_Dec
The Declination of the counterpart to the MAXI/GSC source provided in J2000.0 decimal degree coordinates in the catalogs.

Ctrpart_Offset
Angular separation between the MAXI source position and that of a possible counterpart, in units of degrees. Reported only for the low-latitude sources and the values are reported only for few sources.

Redshift
The redshift of the source given only for extragalactic objects. Reported only for the high galactic latitude sources.

Object_Type
Broad Classification of the Object/Source

Ctrpart_Flags
This parameter contains flags which indicate the catalogs where a counterpart was found. Each catalog is associate with a code. The flag may include more than one code since the source may have a counterpart in more than one catalog. The codes are B, U, X, N, M, and R and represent the catalogs BAT105, 4U, XTEASMLONG, XMMSL2, MCXC, and 1RXS, respectively. The counterpart name listed in the ctrpart_name parameter is quoted from the catalog expressed by the leftmost letter in this parameter field.

Note_Flag
This parameter contains a flag which represents a note related to the identification of the counterpart. The possible values are as follows: 

   Note for the low-galactic latitude sources as reported in the Hori et al paper:
       T: Transient or new MAXI source.
       S: Classified as an XRB in the original catalog (BAT105).
       C: Classified as a symbiotic star in the original catalog (BAT105).

   Note for the high-galactic latitude sources as reported in the Kawamuro et al paper:
      (A): The auto-matching identifies a galaxy cluster, but this is likely
           inconsistent with the significant variability (TSvar = 87).
           Then, we select a star as a plausible candidate of the counterpart.
      (B): We automatically find an obscured AGN from BAT105 as the counterpart,
           but the very soft property is not so common to such objects. Then,
           we find a bright object, CXO J092418.2-314217, in a Swift/XRT soft
           X-ray image. According to a study by Tomsick et al. (2017), it can
           be classified as an LMXB or a CV, and here we representatively adopt
           the LMXB.
      (C): One of the brightest galaxies is selected for the most plausible
           counterpart.

Contact Person

Questions regarding the MAXIGSC7YR database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Wednesday, 21-Apr-2021 16:22:08 EDT