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MYSTIXXRAY - Massive Young Star-Forming Complex Study in IR & X-Rays: X-Ray Source Catalog

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Overview

The Massive Young Star-forming complex Study in Infrared and X-ray (MYStIX) uses data from the Chandra X-Ray Observatory to identify and characterize the young stellar populations in 20 Galactic (d < 4 kpc) massive star-forming regions. In this present study, the X-ray analysis for Chandra ACIS-I observations of 10 of the MYStIX fields is described, and a catalog of > 10,000 X-ray sources is presented in this table. In comparison to other published Chandra source lists for the same regions, the number of MYStIX-detected faint X-ray sources in a region is often doubled. While the higher catalog sensitivity increases the chance of false detections, it also increases the number of matches to infrared stars. X-ray emitting contaminants include foreground stars, background stars, and extragalactic sources. The X-ray properties of sources in these classes are discussed in the reference paper.

The X-ray observations were made with the imaging array on the Advanced CCD Imaging Spectrometer (ACIS-I) on board the Chandra X-Ray Observatory. This array of four CCD detectors subtends 17' x 17' on the sky. The number of different Chandra pointings for each region, the total exposures for these pointings, and details of how the observations were taken are provided in Table 1 of the reference paper. Overall, 29 Chandra ObsIDs are included with typical integration times for a pointing of 40 - 100 ks, sufficient to detect most OB stars and lower-mass pre-main-sequence stars down to ~ 0.5 - 1 solar masses for the MYStIX regions. The 10 MYStIX MSFRs treated herein are listed in Table 2 of the reference paper.

The data were acquired from the Chandra Data Archive from 2001 Jan to Mar 2008 for 10 MYStIX fields (the Flame Nebula, RCW 36, NGC 2264, the Rosette Nebula, the Lagoon Nebula, NGC 2362, DR 21, RCW 38, Trifid Nebula and NGC 1893). The X-ray photometry is from Broos et al. (2010, ApJ, 714, 1582; ACIS Extract); see also the CCCP, Broos et al. (2011, ApJS, 194, 2). The source significance quantities (fb_prob_no_src, sb_prob_no_src, hb_prob_no_src and prob_no_src_min) are computed using a subset of each source's extractions chosen to maximize significance (Broos et al. 2010, ApJ, 714, 1582, Section 6.2). The source position and positional uncertainty quantities are computed using a subset of each source's extractions chosen to minimize the position uncertainty (Broos et al. 2010, ApJ, 714, 1582, Sections 6.2 and 7.1). All other quantities are computed using a subset of each source's extractions chosen to balance the conflicting goals of minimizing photometric uncertainty and of avoiding photometric bias (Broos et al. 2010, ApJ, 714, 1582, Sections 6.2 and 7).

The observed and absorption-corrected energy fluxes and their associated errors and the estimated hydrogen column densities and their uncertainties are derived using non-parametric procedures (XPHOT, Getman et al. 2010, ApJ, 708, 1760). XPHOT assumes the X-ray spectral shapes of young, low-mass stars, which come from coronal X-ray emission. XPHOT quantities will therefore be unreliable for high-mass stars, for which X-ray emission is associated with the stellar wind.


Catalog Bibcode

2013ApJS..209...27K

References

The Massive Young star-forming complex Study in Infrared and X-ray:
X-ray sources in 10 star-forming regions.
    Kuhn M.A., Getman K.V., Broos P.S., Townsley L.K., Feigelson E.D.
   <Astrophys. J. Suppl. Ser., 209, 27 (2013)>
   =2013ApJS..209...27K    (SIMBAD/NED BibCode)

See also:

 B/chandra : The Chandra Archive Log (CXC, 1999-2013)
 J/A+A/539/A74  : NGC1893 Chandra X-ray catalog (Caramazza+, 2012)
 J/ApJ/747/51   : Lagoon Nebula stars. I. Rotation periods (Henderson+, 2012)
 J/ApJS/194/2   : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)
 J/ApJ/743/166  : X-ray and infra-red study of RCW 38 (Winston+, 2011)
 J/ApJ/716/474  : The Rosette star-forming complex. III. (Wang+, 2010)
 J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
 J/ApJ/696/47   : Rosette star-forming complex Chandra study. II. (Wang+, 2009)
 J/AJ/134/999   : X-ray observations of NGC 2264 (Dahm+, 2007)
 J/A+A/460/133  : Chandra X-ray sources in NGC 2362 (Damiani+, 2006)
 J/A+A/455/903  : ACIS-I observations of NGC 2264 (Flaccomio+, 2006)
 J/AJ/132/1100  : X-ray and IR sources in RCW 38 (Wolk+, 2006)
 J/AJ/127/2659  : CHANDRA observations of NGC 2264 (Ramirez+, 2004)
 J/ApJ/607/904  : Chandra obs. of Trifid nebula (Rho+, 2004)
 J/A+A/395/499  : XMM observations in M8 and NGC6530 (Rauw+, 2002)
 J/ApJ/562/446  : X-rays and protostars in Trifid nebula (Rho+, 2001)

Provenance

This table was created by the HEASARC in January 2014 based on CDS Catalog J/ApJS/209 27 file xmystix.dat.

Parameters

SFR_Name
The designation of the MYStIX star-forming region. See Table 2 of the reference paper for more information on the SFRs. These names and the internal source labels identify Chandra pointings; they do not convey membership in astrophysical clusters.

Name
The IAU-style J2000 position-based source designation, e.g., 'CXO JHHMMSS.ss+DDMMSS.s'. Notice that these designations are 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 the prefix CXOU for Chandra X-ray Observatory, Unregistered, and lower-precision coordinates.

Internal_Name
The source designation used within the project for a source in a particular SFR. Thus, by itself this is not necessarily a unique identifier, but also requires the SFR name.

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 radius of the 1-sigma error circle around the X-ray source position, in arcseconds.

Pos_Algorithm
The particular algorithm that was used to estimate the position of the specified X-ray source ("AE correlation", "AE mean data", "AE reconstruction" or "eye").. The algorithms used are described in Section 7.1 of Broos et al. (2010, ApJ, 714, 1582, hereafter B10).

Prob_No_Src_Min
The smallest of the 3 band-dependent 'no-source' probabilities (p-values), fb_prob_no_src,sb_prob_no_src and hb_prob_no_src.

FB_Prob_No_Src
The probability for the 'no-source' hypothesis in the full 0.5-8.0 keV band, i.e., the p-value as described in B10, Section 4.3. In statistical hypothesis testing, the p-value is the probability of obtaining a test statistic at least as extreme as the one that was actually observed when the null hypothesis is true.

SB_Prob_No_Src
The probability for the 'no-source' hypothesis in the soft 0.5-2.0 keV band, i.e., the p-value as described in B10, Section 4.3. In statistical hypothesis testing, the p-value is the probability of obtaining a test statistic at least as extreme as the one that was actually observed when the null hypothesis is true.

HB_Prob_No_Src
The probability for the 'no-source' hypothesis in the hard 2.0-8.0 keV band, i.e., the p-value as described in B10, Section 4.3. In statistical hypothesis testing, the p-value is the probability of obtaining a test statistic at least as extreme as the one that was actually observed when the null hypothesis is true.

Single_Ks_Prob
The smallest p-value for the one-sample Kolmogorov-Smirnov statistic under the no-variability null hypothesis within a single observation. See B10, Section 7.6 for a description of the variability metrics and caveats regarding possible spurious indications of variability using the merged_ks_prob metric.

Merged_Ks_Prob
The smallest p-value for the one-sample Kolmogorov-Smirnov statistic under the no-variability null hypothesis for the merged observations. See B10, Section 7.6 for a description of the variability metrics and caveats regarding possible spurious indications of variability using the merged_ks_prob metric.

Nominal_Exposure
The total nominal exposure time for the X-ray source in the merged observations, in seconds.

Frac_Expo
The fraction of the total nominal exposure time that the X-ray source was observed. Due to dithering over inactive portions of the focal plane, a Chandra source is often not observed during some fraction of the nominal exposure time. (See http://cxc.harvard.edu/ciao/why/dither.html.) The reported quantity is the value of FRACEXPO produced by the CIAO tool mkarf.

Num_Obs_Extracted
The total number of observations of the source that were extracted.

Num_Obs_Merged
The number of observations of the source that were merged so as to estimate its photometric properties.

Frac_Expo_Discard
The fraction of exposures that were discarded in the merging of the observations for the source.

Off_Axis_Min
The smallest off-axis angle ThetaLo of the X-ray source among the merged observations, in arcminutes.

Off_Axis
The average off-axis angle Theta of the X-ray source among the merged observations, in arcminutes.

Off_Axis_Max
The largest off-axis angle ThetaHi of the X-ray source among the merged observations, in arcminutes.

PSF_Fraction
The average PSF fraction at 1.5 keV for the X-ray source in the merged observations.

Aperture_Area
The average aperture area for the X-ray source in the merged observations, in number of pixels of 0.492 by 0.492 arcseconds in size.

Afterglow_Fraction
The suspected afterglow fraction. Since the extracted event data are lightly cleaned to avoid removing legitimate X-ray events from bright sources (B10, Section 3), some background events arising from an effect known as "afterglow" (http://cxc.harvard.edu/ciao/why/afterglow.html) will remain and may contaminate source extractions. After extraction, the authors attempted to identify afterglow events using the tool ae_afterglow_report (see the AE manual at http://www.astro.psu.edu/xray/acis/acis_analysis.html) and report the fraction of extracted events attributed to afterglow in this parameter.

FB_Total_Counts
The observed total-band (0.5-8 keV) total counts in the X-ray source in the merged apertures.

SB_Total_Counts
The observed soft-band (0.5-2 keV) total counts in the X-ray source in the merged apertures.

HB_Total_Counts
The observed hard-band (2-8 keV) total counts in the X-ray source in the merged apertures.

Bck_Scaling
The scaling of the background extraction (See B10, Section 5.4).

FB_Bck_Counts
The observed 0.5-8 keV counts in the merged background regions.

SB_Bck_Counts
The observed 0.5-2 keV counts in the merged background regions.

HB_Bck_Counts
The observed 2-8 keV counts in the merged background regions.

FB_Counts
The net (background-subtracted) 0.5-8 keV counts in the merged apertures.

SB_Counts
The net (background-subtracted) 0.5-2 keV counts in the merged apertures.

HB_Counts
The net (background-subtracted) 2-8 keV counts in the merged apertures.

FB_Counts_Neg_Err
The 1-sigma negative error in the full-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the negative error using the lower bound value given in the original table and the value of the corresponding counts parameter.

FB_Counts_Pos_Err
The 1-sigma positive error in the full-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the positive error using the upper bound value given in the original table and the value of the corresponding counts parameter.

SB_Counts_Neg_Err
The 1-sigma negative error in the soft-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the negative error using the lower bound value given in the original table and the value of the corresponding counts parameter.

SB_Counts_Pos_Err
The 1-sigma positive error in the soft-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the positive error using the upper bound value given in the original table and the value of the corresponding counts parameter.

HB_Counts_Neg_Err
The 1-sigma negative error in the hard-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the negative error using the lower bound value given in the original table and the value of the corresponding counts parameter.

HB_Counts_Pos_Err
The 1-sigma positive error in the hard-band counts. The 68%-confidence intervals for the net counts quantities were estimated by the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html). The HEASARC calculated the positive error using the upper bound value given in the original table and the value of the corresponding counts parameter.

FB_Arf_Value
The mean 0.5-8 keV ancillary response file (ARF) value, in units of cm2 count photon-1. The ARF in ACIS data analysis represents both the effective area of the observatory and the fraction of the observation for which data were actually collected for the source (the fracexpo parameter).

SB_Arf_Value
The mean 0.5-2 keV ancillary response file (ARF) value, in units of cm2 count photon-1. The ARF in ACIS data analysis represents both the effective area of the observatory and the fraction of the observation for which data were actually collected for the source (the fracexpo parameter).

HB_Arf_Value
The mean 2-8 keV ancillary response file (ARF) value, in units of cm2 count photon-1. The ARF in ACIS data analysis represents both the effective area of the observatory and the fraction of the observation for which data were actually collected for the source (the fracexpo parameter).

FB_Median_Energy
The median energy of the observed spectrum of the X-ray source, in the 0.5-8 keV band, in keV. This is the AE quantity ENERG_PCT50_OBSERVED, the median energy of extracted events, corrected for background events (B10, Section 7.3).

SB_Median_Energy
The median energy of the observed spectrum of the X-ray source, in the 0.5-2 keV band, in keV. This is the AE quantity ENERG_PCT50_OBSERVED, the median energy of extracted events, corrected for background events (B10, Section 7.3).

HB_Median_Energy
The median energy of the observed spectrum of the X-ray source, in the 2-8 keV band, in keV. This is the AE quantity ENERG_PCT50_OBSERVED, the median energy of extracted events, corrected for background events (B10, Section 7.3).

FB_Log_Photon_Flux
The logarithm of the incident photon flux in the total (0.5-8keV) band, in photon cm-2 s-1. This is the net counts over the product of the mean effective area in this band (the fb_arf_value) and the nominal exposure time (See B10, Section 7.4).

SB_Log_Photon_Flux
The logarithm of the incident photon flux in the soft (0.5-2keV) band, in photon cm-2 s-1. This is the net counts over the product of the mean effective area in this band (the sb_arf_value) and the nominal exposure time (See B10, Section 7.4).

HB_Log_Photon_Flux
The logarithm of the incident photon flux in the hard (2-8keV) band, in photon cm-2 s-1. This is the net counts over the product of the mean effective area in this band (the hb_arf_value) and the nominal exposure time (See B10, Section 7.4).

HB_Obs_Flux
The observed 2-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

HB_Flux
The absorption-corrected 2-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

HB_Flux_Stat_Err
The 1-sigma statistical uncertainty in the absorption-corrected 2-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

HB_Flux_Sys_Err
The 1-sigma systematic uncertainty in the absorption-corrected 2-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

FB_Obs_Flux
The observed 0.5-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

FB_Flux
The absorption-corrected 0.5-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

FB_Flux_Stat_Err
The 1-sigma statistical uncertainty in the absorption-corrected 0.5-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

FB_Flux_Sys_Err
The 1-sigma systematic uncertainty in the absorption-corrected 0.5-8 keV energy flux of the source, in erg cm-2 s-1, obtained using XPHOT.

Log_NH
The absorbing gas column density N_H, in H atoms cm-2, obtained using XPHOT.

Log_NH_Stat_Err
The 1-sigma statistical uncertainty in the absorbing gas column density N_H, in H atoms cm-2, obtained using XPHOT.

Log_NH_Sys_Err
The 1-sigma systematic uncertainty in the absorbing gas column density N_H, in H atoms cm-2, obtained using XPHOT.


Contact Person

Questions regarding the MYSTIXXRAY database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 21-Feb-2014