J/ApJS/209/27 MYStIX: the Chandra X-ray sources (Kuhn+, 2013)
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 2013ApJS..209...27K
ADC_Keywords: X-ray sources ; H II regions
Keywords: H II regions - stars: activity - stars: formation -
stars: pre-main sequence - X-rays: stars
Abstract:
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<4kpc)
massive star-forming regions. Here, the X-ray analysis for Chandra
ACIS-I observations of 10 of the MYStIX fields is described, and a
catalog of >10000 X-ray sources is presented. 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.
Description:
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'x17' on the sky. Data
were acquired from the Chandra Data Archive from 2001 Jan to Mar 2008 for
10 MYStIX fields (Flame Nebula, RCW 36, NGC 2264, Rosette Nebula,
Lagoon Nebula, NGC 2362, DR 21, RCW 38, Trifid Nebula and NGC 1893);
see table1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 29 Log of Chandra Observations
xmystix.dat 478 11315 *MYStIX X-ray sources and properties
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Note on xmystix.dat: The X-ray photometry is from Broos et al.
2010ApJ...714.1582B 2010ApJ...714.1582B (ACIS Extract); see also the CCCP, Broos et al., 2011,
Cat. J/ApJS/194/2. Rows are sorted by RAdeg.
Source significance quantities (noSrc-t, noSrc-s, noSrc-h, noSrc-m) are
computed using a subset of each source's extractions chosen to maximize
significance (Broos et al. 2010ApJ...714.1582B 2010ApJ...714.1582B, Section 6.2). Source position
quantities (RAdeg, DEdeg, e_pos) are computed using a subset of each source's
extractions chosen to minimize the position uncertainty (Broos et al.
2010ApJ...714.1582B 2010ApJ...714.1582B, 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. 2010ApJ...714.1582B 2010ApJ...714.1582B, Sections 6.2 and 7).
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See also:
J/ApJS/209/28 : MYStIX Wide-Field NIR data: crowded fields (King+, 2013)
J/ApJS/209/29 : MYStIX: MIR observations and catalogs (Kuhn+, 2013)
J/ApJS/209/30 : MYStIX project: Bayesian matching (Naylor+, 2013)
J/ApJS/209/31 : The MYStIX IR-Excess Source catalog (MIRES) (Povich+, 2013)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
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)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Reg Name of the MYStIX star-forming region (G1)
16- 20 I5 --- ObsID [977/12142] Chandra observation ID number
22- 27 I6 --- SeqNum Chandra sequence number (see Cat. B/chandra)
29- 44 A16 "datime" Date UT start time of the observation
46- 51 I6 s Exp [9143/126217] Exposure time (1)
53- 54 I2 h RAh [5/20] Aimpoint hour of RA (J2000) (2)
56- 57 I2 min RAm Aimpoint minute of right ascension (J2000)
59- 63 F5.2 s RAs Aimpoint minute of declination (J2000)
65 A1 --- DE- [±] Aimpoint sign of declination (J2000) (2)
66- 67 I2 deg DEd [1/47] Aimpoint degree of DEC (J2000) (2)
69- 70 I2 arcmin DEm Aimpoint arcminute of declination (J2000)
72- 75 F4.1 arcsec DEs Aimpoint arcsecond of declination (J2000)
77- 79 I3 deg Roll [22/351] Roll angle (2)
81- 90 A10 --- Mode Observation mode ("Faint" or "Very Faint")
92-103 A12 --- PI PI of the observation
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Note (1): Exposure times are the net usable times after various filtering
steps are applied in the data reduction process.
Note (2): The aimpoints and roll angles are obtained from the satellite
aspect solution before astrometric correction is applied.
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Byte-by-byte Description of file: xmystix.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Reg Name of the MYStIX star-forming region (G1)
18- 35 A18 --- CXO IAU source name (HHMMSS.ss+DDMMSS.s; J2000)
37- 45 A9 --- Label Source name used within the project (1)
47- 56 F10.6 deg RAdeg Right ascension (J2000)
58- 67 F10.6 deg DEdeg Declination (J2000)
69- 72 F4.2 arcsec ePos [0/3] 1σ error circle around RA,DE
74- 90 A17 --- PosType Algorithm used to estimate position (2)
92- 95 F4.2 --- no-m [0/0.01] merged p-value for no-source
hypothesis (smallest of no-t/no-s/no-h) (3)
97-100 F4.2 --- no-t [0/0.5] p-value for 0.5-8keV no-source
hypothesis (3)
102-105 F4.2 --- no-s [0/1]? p-value for 0.5-2keV no-source
hypothesis (3)
107-110 F4.2 --- no-h [0/1]? p-value for no-source hypothesis
in the hard (2-8keV) band (3)
112-115 F4.2 --- KS-s [0/1]? Smallest p-value under the
no-variability null hypothesis within a
single-observation (4)
117-120 F4.2 --- KS-m [0/1]? Smallest p-value under the
no-variability null hypothesis over
merged observations (4)
122-130 F9.2 s ExpNom [11844/440602] Total exposure time in
merged observations
132-135 F4.2 --- ExpFrac [0/1] Fraction of ExpN that source was
observed (5)
137 I1 --- Nobs [1/5] Total number of observations extracted
139 I1 --- Nph [1/5] Number of observations merged to
estimate photometry properties
141-144 F4.2 --- Fdis [0/0.9] Fraction of exposure discarded in
merge
146-150 F5.2 arcmin theta-m [0.07/12.2] Smallest value of θ
152-156 F5.2 arcmin theta [0.07/12.2] Average off-axis angle θ for
merged observations
158-162 F5.2 arcmin theta-M [0.07/12.5] Largest value of θ
164-167 F4.2 --- PSFf [0.3/1] Average PSF fraction at 1.5 keV
for merged observations
169-175 F7.2 --- Area [1/2179] Average aperture area for merged
observations in (0.492arcsec)2 units
177-180 F4.2 --- aglow [0/0.4]? Suspected afterglow fraction (6)
182-186 I5 ct Oct-t [2/34654] Observed 0.5-8keV counts in
merged apertures
188-192 I5 ct Oct-s [0/31233] Observed 0.5-2keV counts in
merged apertures
194-197 I4 ct Oct-h [0/5668] Observed 2-8keV counts in merged
apertures
199-206 F8.2 --- bgScl [0.5/10864] Scaling of background extraction
208-212 I5 ct bgct-t [0/15263] Observed 0.5-8keV counts in merged
background regions
214-218 I5 ct bgct-s [0/14105] Observed 0.5-2keV counts in merged
background regions
220-223 I4 ct bgct-h [0/1527] Observed 2-8keV counts in merged
background regions
225-231 F7.1 ct Nct-t [0.8/34588] Net 0.5-8keV counts in merged
apertures
233-239 F7.1 ct Nct-s [-7.1/31173] Net 0.5-2keV counts in merged
apertures
241-247 F7.1 ct Nct-h [-11/5667] Net 2-8keV counts in merged
apertures
249-255 F7.1 ct b_Nct-t [0/34402] 1σ lower bound on NCtst (7)
257-263 F7.1 ct B_Nct-t [2/34776] 1σ upper bound on NCtst (7)
265-271 F7.1 ct b_Nct-s [0/30997]? 1σ lower bound on NCtss (7)
273-279 F7.1 ct B_Nct-s [0/31352] 1σ upper bound on NCtss (7)
281-287 F7.1 ct b_Nct-h [0/5592]? 1σ lower bound on NCtsh (7)
289-295 F7.1 ct B_Nct-h [0/5743] 1σ upper bound on NCtsh (7)
297-302 F6.2 --- Area-t [19/247] Mean effective area (ARF value)
in cm2.count/photon in 0.5-8keV (8)
304-309 F6.2 --- Area-s [29/360] Mean effective area (ARF value)
in cm2.count/photon in 0.5-2keV (8)
311-316 F6.2 --- Area-h [17.3/219] Mean effective area (ARF value)
in cm2.count/photon in 2-8keV (8)
318-322 F5.2 keV E-t [0.5/7.5] Median 0.5-8keV energy, observed
spectrum (9)
324-328 F5.2 keV E-s [0/2]? Median 0.5-2keV energy, observed
spectrum (9)
330-334 F5.2 keV E-h [0/8]? Median 2-8keV energy, observed
spectrum (9)
336-342 F7.3 [ph/cm2/s] XFlx-t [-7.8/-3.1] log incident photon flux
in total (0.5-8keV) band (10)
344-350 F7.3 [ph/cm2/s] XFlx-s [-11.7/0]? log incident photon flux
in soft (0.5-2keV) band (10)
352-358 F7.3 [ph/cm2/s] XFlx-h [-10.5/0]? log incident photon flux
in hard (2-8keV) band (10)
360-371 E12.6 mW/m2 Flux-h [0/2.5e-12]? 2-8 keV X-ray flux (11)
373-384 E12.6 mW/m2 Flxc-h [0/4.7e-12]? Absorption-corrected
2-8 keV X-ray flux
386-397 E12.6 mW/m2 e_Flxc-h [0/3.6e-13]? 1σ statistical
uncertainty on Flxc-h
399-410 E12.6 mW/m2 s_Flxc-h [0/4.3e-13]? 1σ systematic
uncertainty on Flxc-h
412-423 E12.6 mW/m2 Flux-t [0/2.6e-12]? 0.5-8 keV X-ray flux
425-436 E12.6 mW/m2 Flxc-t [0/1.1e-11]? Absorption-corrected
0.5-8 kev X-ray flux
438-449 E12.6 mW/m2 e_Flxc-t [0/8.7e-13]? 1σ statistical
uncertainty on Flxc-t
451-462 E12.6 mW/m2 s_Flxc-t [0/1.9e-12]? 1σ systematic
uncertainty on Flxc-t
464-468 F5.2 cm-2 logNH [0/24]? Gas column density
470-473 F4.2 cm-2 e_logNH [0/1.1]? 1σ statistical
uncertainty on logNH
475-478 F4.2 cm-2 s_logNH [0/1.2]? 1σ systematic
uncertainty on logNH
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Note (1): Source labels identify a Chandra pointing; they do not convey
membership in astrophysical clusters.
Note (2): Algorithm used to estimate position from Broos et al.
2010ApJ...714.1582B 2010ApJ...714.1582B, Section 7.1 ("AE correlation", "AE mean data",
"AE reconstruction" or "eye").
Note (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.
(See Broos et al. 2010ApJ...714.1582B 2010ApJ...714.1582B, Section 4.3)
Note (4): Smallest p-value for the one-sample Kolmogorov-Smirnov statistic.
Note (5): 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 FRACEXPO produced by the CIAO tool mkarf.
Note (6): Some background events arising from an effect known as "afterglow"
(http://cxc.harvard.edu/ciao/why/afterglow.html) may contaminate
source extractions, despite careful procedures to identify and remove
them during data preparation (Broos et al. 2010ApJ...714.1582B 2010ApJ...714.1582B,
Section 3). After extraction, we attempt to identify afterglow events
using the tool aeafterglowreport, and report the fraction of
extracted events attributed to afterglow; see the ACIS Extract manual
(http://www.astro.psu.edu/xray/acis/acis_analysis.html).
Note (7): Confidence intervals (68%) for NetCounts quantities are estimated by
the CIAO tool aprates
(http://asc.harvard.edu/ciao/ahelp/aprates.html).
Note (8): The ancillary response file (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
(ExposureFraction)
Note (9): MedianEnergy is the median energy of extracted events, corrected for
background (Broos et al. 2010ApJ...714.1582B 2010ApJ...714.1582B, Section 7.3).
Note (10): XFlx=(NCt/Area/ExpNom);
Broos et al. 2010ApJ...714.1582B 2010ApJ...714.1582B, Section 7.4.
Note (11): XPHOT assumes 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 (Getman et al. 2010,
Cat. J/ApJ/708/1760).
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Global Notes:
Note (G1): the regions are: DR 21, Flame Nebula, Lagoon Nebula,
NGC 1893, NGC 2264, NGC 2362, RCW 36, RCW 38,
Rosette Nebula, Trifid Nebula
History:
From electronic version of the journal
References:
Feigelson et al. Overview. 2013ApJS..209...26F 2013ApJS..209...26F
Kuhn et al. X-ray sources. 2013ApJS..209...27K 2013ApJS..209...27K (this paper)
King et al. Optimal photometry. 2013ApJS..209...28K 2013ApJS..209...28K Cat. J/ApJS/209/28
Kuhn et al. MIR. 2013ApJS..209...29K 2013ApJS..209...29K Cat. J/ApJS/209/29
Naylor et al. Bayesian matching. 2013ApJS..209...30N 2013ApJS..209...30N Cat. J/ApJS/209/30
Povich et al. IR excess cat. 2013ApJS..209...31P 2013ApJS..209...31P Cat. J/ApJS/209/31
Broos et al. Young stars. 2013ApJS..209...32B 2013ApJS..209...32B Cat. J/ApJS/209/32
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 20-Dec-2013