The 37-month MAXI/GSC source catalog in the high Galactic-latitude sky

TL;DR

This paper presents a high-sensitivity, 37-month X-ray source catalog from MAXI/GSC, detecting 500 sources at high Galactic latitudes with detailed statistical properties and cross-matching with other catalogs.

Contribution

The first 37-month high Galactic-latitude X-ray source catalog from MAXI/GSC with improved sensitivity and comprehensive source characterization.

Findings

Detected 500 sources in the 4-10 keV band with high significance.

Achieved the highest all-sky survey sensitivity in this energy band.

Provided detailed cross-matching with other X-ray catalogs.

Abstract

We present the catalog of high Galactic-latitude ($|b|>10^{\circ}$) X-ray sources detected in the first 37-month data of Monitor of All-sky X-ray Image (MAXI) / Gas Slit Camera (GSC). To achieve the best sensitivity, we develop a background model of the GSC that well reproduces the data based on the detailed on-board calibration. Source detection is performed through image fit with the Poisson likelihood algorithm. The catalog contains 500 objects detected in the 4--10 keV band with significance of $s_{\rm D, 4-10 keV} \geq 7$. The limiting sensitivity is $\approx 7.5\times10^{-12}$ ergs cm$^{-2}$ s$^{-1}$ ($\approx 0.6$ mCrab) in the 4--10 keV band for 50% of the survey area, which is the highest ever achieved as an all-sky survey mission covering this energy band. We summarize the statistical properties of the catalog and results from cross matching with the Swift/BAT 70-month catalog, the meta-catalog of X-ray detected clusters of galaxies, and the MAXI/GSC 7-month catalog. Our catalog lists the source name (2MAXI), position and its error, detection significances and fluxes in the 4--10 keV and 3--4 keV bands, their hardness ratio, and basic information of the likely counterpart available for 296 sources.