M 37 Chandra X-Ray Point Source Catalog

Empirical calibrations of the stellar age-rotation-activity relation (ARAR) rely on observations of the co-eval populations of stars in open clusters. The authors used the Chandra X-ray Observatory to study M 37 (NGC 2099), a 500-Myr-old open cluster that has been extensively surveyed for rotation periods (P_rot). M 37 was observed almost continuously for five days, for a total of 440.5 ks, to measure stellar X-ray luminosities (L_X), a proxy for coronal activity, across a wide range of masses. The cluster's membership catalog was revisited to calculate updated membership probabilities from photometric data and each star's distance to the cluster center. The result is a comprehensive sample of 1699 M 37 members: 426 with P_rot, 278 with X-ray detections, and 76 with both. The authors calculate Rossby numbers, R_o= P_rot/tau , where tau is the convective turnover time, and ratios of the X-ray-to-bolometric luminosity, L_X/L_bol, to minimize mass dependencies in their characterization of the rotation-coronal activity relation at 500 Myr. They find that fast rotators, for which R_o < 0.09 +/- 0.01, show saturated levels of activity, with log(L_X/L_bol) = -3.06 +/- 0.04. For R_o >= 0.09 +/- 0.01, activity is unsaturated and follows a power law of the form R^beta_o , where beta = -2.03 (-0.14, +0.17). This is the largest sample available for analyzing the dependence of coronal emission on rotation for a single-aged population, covering stellar masses in the range 0.4 - 1.3 solar masses, P_rot in the range 0.4 - 12.8 days, and L_X in the range 10^28.4 - 10^30.5 erg s^-1. These results make M 37 a new benchmark open cluster for calibrating the ARAR at ages of ~ 500 Myr. The central field of M 37 was observed five separate times between 2011 November 14 20:58 and 2011 November 1915:31 UTC for a total of 440.5 ks with the Advanced CCD Imaging Spectrometer (ACIS). The four ACIS-I chips and the ACIS-S3 chip were used in Very Faint telemetry mode to improve the screening of background events and thus increase the sensitivity of ACIS to faint sources. The exposure-weighted average aimpoint of the 16.9 x 16.9 arcmin² ACIS-I field of view is RA = 05^h 52^m 17.86^s,Dec = +32^o 33' 48.23" (J2000). The pitch angle for four observations was 103 degrees; due to scheduling constraints, it was 253 degrees for the fifth. Table 1 in the reference paper provides the basic information for the 5 Chandra observations and Figure 1 in that paper shows their footprints superimposed on a 40' x 40' i' image centered on M 37 obtained by Hartman et al. (2008, ApJ, 675, 1233, hereafter HA08) with the Megacam on the MMT telescope. This HEASARC table contains all of the data from Table 3 of the reference paper, the M 37 Chandra catalog of 774 X-ray sources, and the data from Table 5, the catalog of optical objects, for those objects which have been identified as optical counterparts to the X-ray sources. It does not contain entries for those optical objects in Table 5 which lack X-ray counterparts. This online catalog was created by the HEASARC in December 2015 based on machine-readable versions of tables 3 and 5 from the paper which were obtained from the ApJ website. This is a service provided by NASA HEASARC .

                                            [
  "026:00"
]
                                        

                                            {
  "fn": "Tess Jaffe",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:tess.jaffe@nasa.gov"
}
                                        

                                            [
  {
    "@type": "dcat:Distribution",
    "title": "Data Information (HTML)",
    "format": "HTML",
    "mediaType": "text/html",
    "downloadURL": "https://heasarc.gsfc.nasa.gov/W3Browse/all/m37cxo.html"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Data Information (Unknown Format)",
    "format": "BIN",
    "mediaType": "application/octet-stream",
    "downloadURL": "https://heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets&table=m37cxo&"
  }
]
                                        

                                            [
  "na"
]
                                        

                                            [
  "026:000"
]
                                        

                                            {
  "name": "High Energy Astrophysics Science Archive Research Center",
  "@type": "org:Organization"
}
                                        

                                            [
  "Astrophysics"
]