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SFINCSXRAY - Star Formation in Nearby Clouds (SFiNCs) X-Ray Source Catalog

HEASARC
Archive

Overview

The Star Formation in Nearby Clouds (SFiNCs) project is aimed at providing a detailed study of the young stellar populations and of star cluster formation in the nearby 22 star-forming regions (SFRs) for comparison with our earlier MYStIX survey of richer, more distant clusters. As a foundation for the SFiNCs science studies, in the reference paper homogeneous data analyses of the Chandra X-ray and Spitzer mid-infrared archival SFiNCs data are described, and the resulting catalogs of over 15,300 X-ray and over 1,630,000 mid-infrared point sources are presented. On the basis of their X-ray/infrared properties and spatial distributions, nearly 8500 point sources have been identified as probable young stellar members of the SFiNCs regions. Compared to the existing X-ray/mid-infrared publications, the SFiNCs member list increases the census of YSO members by 6%-200% for individual SFRs and by 40% for the merged sample of all 22 SFiNCs SFRs.

Sixty-five X-ray observations of the 22 SFiNCs SFRs made with the imaging array on the Advanced CCD Imaging Spectrometer (ACIS) were extracted from the Chandra archive (spanning from 2000 January to 2015 April). See Tables 1 and 2 of the reference paper for the list of SFRs and the log of Chandra ACIS observations, respectively. The final Chandra-ACIS catalog for the 22 SFiNCs SFRs comprises 15,364 X-ray sources (presented in Tables 3 and 4 and section 3.2 of the reference paper, and the contents of this HEASARC table, SFINCSXRAY).

To obtain MIR photometry for X-ray objects and to identify and measure MIR photometry for additional non-Chandra disky stars that were missed in previous studies of the SFiNCs regions (typically faint YSOs), the authors have reduced the archived Spitzer-IRAC data by homogeneously applying the MYStIX-based Spitzer-IRAC data reduction methods of Kuhn et al. (2013, ApJS, 209, 29) to the 423 Astronomical Object Request (AORs) data sets for the 22 SFiNCs SFRs (Table 5 of the reference paper). As in MYStIX, the SFiNCs IRAC source catalog retains all point sources with the photometric signal-to-noise ratio > 5 in both [3.6] and [4.5] um channels. This catalog covers the 22 SFiNCs SFRs and their vicinities on the sky and comprises 1,638,654 IRAC sources with available photometric measurements for 100%, 100%, 29%, and 23% of these sources in the 3.6, 4.5, 5.8, and 8.0um bands, respectively (see table 6 and section 3.4 of the reference paper).

Source position cross-correlations between the SFiNCs Chandra X-ray source catalog and an IR catalog, either the "cut-out" IRAC or 2MASS, were made using the steps described in section 3.5 of the reference paper.

Tables 7 and 8 of the reference paper provide the list of 8,492 SFiNCs probable cluster members (SPCMs) and their main IR and X-ray properties (see section 4 of the reference paper): this list as available at the HEASARC as the SFINCSPCM table (q.v.).


Catalog Bibcode

2017ApJS..229...28G

References

Star Formation in Nearby Clouds (SFiNCs): X-ray and infrared source catalogs
and membership.
    Getman K.V., Broos P.S., Kuhn M.A., Feigelson E.D., Richert A.J.W., Ota Y.,
    Bate M.R., Garmire G.P.
   <Astrophys. J. Suppl. Ser., 229, 28-28 (2017)>
   =2017ApJS..229...28G    (SIMBAD/NED BibCode)

Provenance

This table was created by the HEASARC in September 2017 based on the CDS Catalog J/ApJS/229/28 files table3.dat (the list of SFiNCs X-ray sources and their basic properties) and table4.dat (the list of SFiNCs X-ray source fluxes).

Parameters

SFR_Name
The SFiNCs star formation region (SFR) identifier. The SFRs studied herein and their basic properties are listed in Table 1 of the reference paper. These names and the associated source numbers identify the Chandra pointings in which they were detected; they do not necessarily imply membership in the astrophysical clusters.

SFR_Source_Number
A unique number identifying the X-ray source detected in the Chandra pointing towards the specified SFR (sfr_name parameter), and. sorted in order of increasing J2000.0 RA. Notice that the sfr_source_number by itself is not unique. To uniquely specify an X-ray source both the SFR name and source number are required, e.g., 'NGC 7822 1'.

Name
The IAU-style J2000 position-based source designation, e.g., 'CXOU JHHMMSS.ss+DDMMSS.s'. Notice that these designations are somewhat non-standard according to the guidelines of the Dictionary of Nomenclature of Celestial Objects, which would suggest that they should be of the form 'CXOU JHHMMSS.s+DDMMSS', i.e., with lower-precision coordinates.

RA
The Right Ascension of the X-ray source in the selected equinox. This was given in J2000 decimal degree coordinates to an accuracy of 10-6 degrees (0.0036 arcseconds) in the original reference.

Dec
The Declination of the X-ray source in the selected equinox. This was given in J2000 decimal degree coordinates to an accuracy of 10-6 degrees (0.0036 arcseconds) in the original reference.

LII
The Galactic Longitude of the X-ray source.

BII
The Galactic Latitude of the X-ray source.

Error_Radius
The estimated standard deviation of the random component of the position error of the X-ray source, sqrt(sigmax2 + sigmay2), in arcseconds. The single-axis position errors, sigmax and sigmay , are estimated from the single-axis standard deviations of the PSF inside the extraction region and the number of counts extracted. radius of the 1-sigma error circle around the X-ray source position.

Off_Axis
The off-axis angle of the X-ray source from the ACIS aimpoint, in arcminutes.

FB_Counts
The net counts extracted from the source extraction region in the total energy band (0.5-8 keV).

FB_Counts_Error
The average of the upper and lower 1-sigma errors in the net counts extracted from the source extraction region in the total energy band (0.5-8 keV).

FB_Bck_Counts
The background counts expected in the source extraction region in the total energy band (0.5-8 keV).

HB_Counts
The net counts extracted from the source extraction region in the hard energy band (2-8 keV).

PSF_Fraction
The fraction of the PSF (at 1.497 keV) that is enclosed within the source extraction region. A reduced PSF fraction (significantly below 90%) may indicate that the source is in a crowded region.

FB_SNR
The photometric significance computed as the net counts divided by the upper error in the net counts.

Log_FB_Prob_No_Src_Limit
If the corresponding value of the log_fb_prob_no_src parameter is an upper limit, this flag parameter is set to '<'.

Log_FB_Prob_No_Src
The logarithmic probability log PB that the extracted counts (total band) are solely from the background. Some sources have PB values above the 1% threshold that defines the catalog because local background estimates can rise during the final extraction iteration after sources are removed from the catalog.

Source_Anomaly_Flags
Flags that indicate the presence of source anomalies as follows:

    Value   Meaning

    g       The fractional time that the source was on a detector (FRACEXPO from
              mkarf) is <0.9;
    e       The source is on a field edge;
    p       The X-ray properties may be biased due to photon pile-up;
    s       The source is on a readout streak;
    a       The photometry and spectrum of the source may contain >10% afterglow
              events.
  

Source_Variable_Flag
A flag that indicates the variability characterization of the source based on the K-S statistic (total band) probability that the source is constant (PKS) from the single Chandra ObsID showing the most variability, as follows:

    Value   Meaning

    a       No evidence for variability (0.05 < PKS);
    b       Possibly variable (0.005 < PKS < 0.05);
    c       Definitely variable (PKS < 0.005).
  
No value is reported for sources with fewer than four counts or for sources in chip gaps or on field edges.

Median_Energy
The background-corrected median photon energy in the total band (0.5-8 keV), in keV.

HB_Log_Photon_Flux
The logarithm of the incident X-ray photon flux in the hard band (2-8 keV), in photon cm-2 s-1, as produced by AE (Broos et al. 2010, ApJ, 714, 1582).

FB_Log_Photon_Flux
The logarithm of the incident X-ray photon flux in the total band (0.5-8 keV), in photon cm-2 s-1, as produced by AE (Broos et al. 2010, ApJ, 714, 1582).

HB_Log_Flux
The logarithm of the apparent X-ray flux in the hard band (2-8 keV), in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760). XPHOT assumes the X-ray spectral shape appropriate for young, low-mass stars. Intrinsic XPHOT quantities will be unreliable for high-mass stellar members of the SFiNCs SFRs as well as for non-members, such as Galactic field stars and extragalactic objects.

HB_Log_Flux_Error
The 1-sigma statistical uncertainty in the logarithm of the apparent X-ray flux in the hard band (2-8 keV), in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).

FB_Log_Flux
The logarithm of the apparent X-ray flux in the total band (0.5-8 keV), in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760). XPHOT assumes the X-ray spectral shape appropriate for young, low-mass stars. Intrinsic XPHOT quantities will be unreliable for high-mass stellar members of the SFiNCs SFRs as well as for non-members, such as Galactic field stars and extragalactic objects.

FB_Log_Flux_Error
The 1-sigma statistical uncertainty in the logarithm of the apparent X-ray flux in the total band (0.5-8 keV), in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).

Log_NH
The logarithm of the X-ray-derived absorbing column density as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760), in H atom cm-2. XPHOT assumes the X-ray spectral shape appropriate for young, low-mass stars. Intrinsic XPHOT quantities will be unreliable for high-mass stellar members of the SFiNCs SFRs as well as for non-members, such as Galactic field stars and extragalactic objects.

Log_NH_Error
The 1-sigma statistical error in the logarithm of the X-ray-derived absorbing column density as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760), in H atom cm-2.

Log_NH_Sys_Err
The 1-sigma systematic error in the logarithm of the X-ray-derived absorbing column density as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760), in H atom cm-2.

HB_Log_Corr_Flux
The logarithm of the X-ray flux in the hard band (2-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760). XPHOT assumes the X-ray spectral shape appropriate for young, low-mass stars. Intrinsic XPHOT quantities will be unreliable for high-mass stellar members of the SFiNCs SFRs as well as for non-members, such as Galactic field stars and extragalactic objects.

HB_Log_Corr_Flux_Error
The 1-sigma statistical error in the logarithm of the X-ray flux in the hard band (2-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).

HB_Log_Corr_Flux_Sys_Err
The 1-sigma systematic error in the logarithm of the X-ray flux in the hard band (2-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).

FB_Log_Corr_Flux
The logarithm of the X-ray flux in the total band (0.5-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760). XPHOT assumes the X-ray spectral shape appropriate for young, low-mass stars. Intrinsic XPHOT quantities will be unreliable for high-mass stellar members of the SFiNCs SFRs as well as for non-members, such as Galactic field stars and extragalactic objects.

FB_Log_Corr_Flux_Error
The 1-sigma statistical error in the logarithm of the X-ray flux in the total band (0.5-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).

FB_Log_Corr_Flux_Sys_Err
The 1-sigma systematic error in the logarithm of the X-ray flux in the total band (0.5-8 keV) after being corrected for absorption, in erg cm-2 s-1, as produced by XPHOT (Getman et al. 2010, ApJ, 708, 1760).


Contact Person

Questions regarding the SFINCSXRAY database table can be addressed to the HEASARC User Hotline.
Page Author: Browse Software Development Team
Last Modified: Thursday, 14-Sep-2017 13:07:28 EDT