MAXISSCCAT - MAXI/SSC Catalog of X-Ray Sources in 0.7-7.0 keV Band

Overview

This table contains the first source catalog of the Solid-state Slit Camera (SSC) of the Monitor of All-sky X-ray Image (MAXI) mission located on the International Space Station, using the 45 months of data from 2010 August 1 to 2014 April 30 in the 0.7-7.0 keV band. Sources were searched for in two energy bands, 0.7-1.85 keV (the soft band) and 1.85-7.0 keV (the hard band), limiting sensitivities of 3 and 4 mCrab, respectively, were achieved, and 140 and 138 sources were detected in the soft and hard energy bands, respectively. Combining the two energy bands, 170 sources are listed in the MAXI/SSC catalog. All but 2 sources are identified, with 22 galaxies (including AGNs), 29 cluster of galaxies, 21 supernova remnants, 75 X-ray binaries, 8 stars, 5 isolated pulsars, and 9 non-categorized objects. Comparing the soft-band fluxes at the brightest end in this catalog with the ROSAT survey, which was performed about 20 years ago, 10% of the catalogued sources are found to have changed flux since the ROSAT era.

Catalog Bibcode

2016PASJ...68S..32T

References

The first MAXI/SSC catalog of X-ray sources in 0.7-7.0keV.
    Tomida H., Uchida D., Tsunemi H., Imatani R., Kimura M., Nakahira S.,
    Hanayama T., Yoshidome K.
   <Publ. Astron. Soc. Jap. 68, S32 (2016)>
   =2016PASJ...68S..32T    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in December 2016 based on CDS Catalog J/PASJ/68/S32 file table5.dat.

Parameters

Source_Number
A unique X-ray source number in order of increasing J2000.0 Right Ascension. This form has not as of December 2016 been registered with the CDS Dictionary of Nomenclature of Celestial Objects.

Name
The name of the source using the '1MAXIS' prefix for 'First MAXI SSC' and the J2000.0 coordinates, e.g., 'MAXIS JHHMM+DDd'.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000.0 decimal degree coordinates to a precision of 10-^-2 degrees (36 arcseconds) in the original table. The nominal precision of these positions is 0.02 degrees (1.2 arcminutes) but may be worse than this in crowded regions of the sky.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000.0 decimal degree coordinates to a precision of 10-^-2 degrees (36 arcseconds) in the original table. The nominal precision of these positions is 0.02 degrees (1.2 arcminutes) but may be worse than this in crowded regions of the sky.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

SB_Significance
The soft (0.7-1.85 keV) band significance level S_D of the X-ray source. The authors compare the number of events in a candidate source region with that of the background region. Each candidate region is a circle with a radius of 1.5 degrees, and the background region is an contiguous annular region with the outer radius of 3.0 degrees. The authors then define the significance level, S_D , as

     S_D = [N_s - (N_b x S_c)]/sqrt{N_s + (N_b x S_c²},

where N_s is the number of events in the candidate region, N_b is the number of counts in the background region, and S_c is the ratio of the areas of the candidate to the background regions. The authors define S_D > 5.0 as the threshold for a significant detection. Crowded regions were treated with caution. When a region overlapped those of other sources, the authors simply excluded the overlapping region. However, when the nearby source was determined to be insignificant (or fake), they recalculated the source and/or background region, and iterated this process to calculate the significance S_D until no fake source was obtained.

HB_Significance
The hard (1.85-7.0 keV) band significance level S_D of the X-ray source. The authors compare the number of events in a candidate source region with that of the background region. Each candidate region is a circle with a radius of 1.5 degrees, and the background region is an contiguous annular region with the outer radius of 3.0 degrees. The authors then define the significance level, S_D , as

     S_D = [N_s - (N_b x S_c)]/sqrt{N_s + (N_b x S_c²},

SB_Flux
The soft (0.7-1.85 keV) band flux of the X-ray source in erg s^-1 cm^-2. The flux is calculated only when the corresponding source significance S_D > 5. The source flux was evaluated from the number of events in the background-subtracted image. The authors then compared it with the number of events in the Crab simulation, where they assumed a photon index of 2.1, an interstellar absorption N_H of 3.4 x 10²¹ cm^-2 with solar abundances, and a photon flux density at 1.0 keV of 10 photon sec^-1 cm^-2 keV^-1. The authors performed the simulation, using XSPEC version 12.8.2 and the spectrum response files created in the same way as those distributed at the MAXI web site. In the SSC data of the Crab observations, they find the flux to be 8.21 x 10^-9 and 1.824 x 10^-8 erg sec^-1 cm^-2 for the soft and the hard bands, respectively. On the other hand, their simulation of the Crab gave fluxes of 9.34 x 10^-9 and 1.807 x 10^-8 erg sec^-1 cm^-2, respectively. Hence, the observed results with the SSC are 0.88 and 1.01 times that of the simulation. Although this difference depends partially on the systematic error of the SSC normalization, the differences mainly depends on the spectral model. The Crab model that was employed was determined with the INTEGRAL mission, for which the energy range is > 3 keV. Thus, the discrepancy in the soft band is larger than that of the hard band.

HB_Flux
The hard (1.85-7.0 keV) band flux of the X-ray source in erg s^-1 cm^-2. The flux is calculated only when the corresponding source significance S_D > 5. The source flux was evaluated from the number of events in the background-subtracted image. The authors then compared it with the number of events in the Crab simulation, where they assumed a photon index of 2.1, an interstellar absorption N_H of 3.4 x 10²¹ cm^-2 with solar abundances, and a photon flux density at 1.0 keV of 10 photon sec^-1 cm^-2 keV^-1. The authors performed the simulation, using XSPEC version 12.8.2 and the spectrum response files created in the same way as those distributed at the MAXI web site. In the SSC data of the Crab observations, they find the flux to be 8.21 x 10^-9 and 1.824 x 10^-8 erg sec^-1 cm^-2 for the soft and the hard bands, respectively. On the other hand, their simulation of the Crab gave fluxes of 9.34 x 10^-9 and 1.807 x 10^-8 erg sec^-1 cm^-2, respectively. Hence, the observed results with the SSC are 0.88 and 1.01 times that of the simulation. Although this difference depends partially on the systematic error of the SSC normalization, the differences mainly depends on the spectral model. The Crab model that was employed was determined with the INTEGRAL mission, for which the energy range is > 3 keV. Thus, the discrepancy in the soft band is larger than that of the hard band.

Alt_Name
The source identification, typically the most commonly used name for the source.

Source_Type
The source type using the following abbreviations:

     AGN:  active galactic nucleus
      BH:  black hole
      GC:  cluster of galaxies
      NS:  neutron star
     SNR:  supernova remnant
      WD:  white dwarf

MAXI_GSC_Name
The counterpart to the MAXI SSC X-ray source in the Second MAXI/GSC (2MAXI) Catalog, available in the HEASARC database as the MAXIGSCHGL table.

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

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:30:58 EDT