J/ApJS/244/28 The 3rd MSFRs Omnibus X-ray Catalog (MOXC3) (Townsley+, 2019)
The Massive Star-forming Regions Omnibus X-ray Catalog, Third installment.
Townsley L.K., Broos P.S., Garmire G.P., Povich M.S.
<Astrophys. J. Suppl. Ser., 244, 28 (2019)>
=2019ApJS..244...28T 2019ApJS..244...28T
ADC_Keywords: Star Forming Region; H II regions; X-ray sources
Keywords: H II regions ; Early-type stars ; Star formation ; X-ray stars
Abstract:
We offer to the star formation community the third installment of the
Massive Star-forming Regions (MSFRs) Omnibus X-ray Catalog (MOXC3), a
compilation of X-ray point sources detected in 50 archival Chandra
Advanced CCD Imaging Spectrometer observations of 14 Galactic MSFRs
and surrounding fields. The MOXC3 MSFRs are NGC2264, NGC6193,
RCW108-IR, AurOB1, DR15, NGC6231, Berkeley87, NGC6357, AFGL4029, hPer
(NGC869), NGC281, Onsala2S, G305, and RCW49 (Wd2); they have distances
of 0.7-4.2kpc. Most exhibit clumped or clustered young stellar
populations; several contain at least two distinct massive young
stellar clusters. The total MOXC3 catalog includes 27923 X-ray point
sources. We take great care to identify even the faintest X-ray point
sources across these fields. This allows us to remove this point
source light, revealing diffuse X-ray structures that pervade and
surround MSFRs, often generated by hot plasmas from massive star
feedback. As we found in MOXC1 and MOXC2, diffuse X-ray emission is
traceable in all MOXC3 MSFRs; here we perform spectral fitting to
investigate the origins of selected diffuse regions. Once again, MOXC3
shows the value of high spatial resolution X-ray studies of MSFRs
enabled by Chandra.
Description:
The analysis methods for the Massive Star-forming Regions Omnibus
X-ray Catalog, third installment (MOXC3) are nearly identical to those
employed in MOXC2. The one major extension is that MOXC3 introduces
the analysis of zeroth-order data from ACIS observations that included
the Chandra High Energy Transmission Gratings (HETG;
Canizares+ 2005PASP..117.1144C 2005PASP..117.1144C). MOXC3 also incorporates newly
available Gaia DR2 (Gaia Collaboration, 2018, I/345) distances from
the literature for most targets. Lastly, we revive our workflow for
spectral fitting of diffuse X-ray emission regions from the Chandra
Carina Complex Project (CCCP; Townsley+ 2011, J/ApJS/194/15 ;
2011ApJS..194...16T 2011ApJS..194...16T and 2011ApJS..194....1T 2011ApJS..194....1T) to ascertain the origins
of prominent patches of diffuse X-ray emission in MOXC3 MSFRs.
See Section 2 for further details.
Table 2 enumerates the 50 archival Chandra/ACIS observations used in
MOXC3 by listing their unique Observation Identification (ObsID)
numbers. Details are given in MOXC2 (Townsley+ 2018, J/ApJS/235/43).
Most MOXC3 data were obtained with the ACIS Imaging Array (ACIS-I)
configuration.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
moxc3.dat 560 27923 *MOXC3 Chandra point source catalog (see Table 3)
table1.dat 152 15 MOXC3 targets
table2.dat 161 50 Log of Chandra observations
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Note on moxc3.dat: These X-ray columns are produced by the ACIS Extract
(AE; Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B) software package. Similar column
labels were previously published by the CCCP (Broos+ 2011, J/ApJS/194/2),
MOXC1 (Townsley+ 2014, J/ApJS/213/1), and MOXC2
(Townsley+ 2018, J/ApJS/235/43). AE and its User's Guide are publicly
available from the Astrophysics Source Code Library, from Zenodo, and
at http://personal.psu.edu/psb6/TARA/ae_users_guide.html.
All quantities are computed using a subset of ObsIDs, chosen
independently for each source, to balance the conflicting goals of
minimizing photometric uncertainty and of avoiding photometric bias
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Sections 6.2 and 7); except for the
variability indices (ProbKS_single, ProbKS_merge,
ProbChisq_PhotonFlux) which are computed using all ObsIDs.
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Description of file:
In the FTP section, xray_properties.fits.gz is the original MOXC3
catalog in FITS format (gzip).
See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
IX/45 : The Chandra Source Catalog, Release 1.1 (Evans+ 2012)
III/274 : Galactic O-Star Spectroscopic Survey (GOSSS) (Sota+, 2014)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/347 : Distances to 1.33 billion stars in Gaia DR2 (Bailer-Jones+, 2018)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
IX/57 : The Chandra Source Catalog (CSC), Release 2.0 (Evans+, 2019)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
J/A+A/400/533 : New IR star clusters in southern Milky Way (Dutra+, 2003)
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
J/A+A/455/903 : ACIS-I observations of NGC 2264 (Flaccomio+, 2006)
J/A+A/454/1047 : XMM view of NGC 6231 open cluster (Sana+, 2006)
J/MNRAS/372/661 : XMM view of NGC 6231: OB stars (Sana+, 2006)
J/A+A/468/353 : XMM-Newton Extended Survey of Taurus (Guedel+, 2007)
J/A+A/463/981 : BV CCD photometry in Westerlund 2 (Rauw+, 2007)
J/ApJ/665/719 : X-ray imaging of RCW 49 (Tsujimoto+, 2007)
J/ApJS/168/100 : X-ray study of star-forming region NGC 6357 (Wang+, 2007)
J/ApJ/688/1142 : Star formation in W5: Spitzer observations (Koenig+, 2008)
J/MNRAS/386/447 : RV catalogue of O-type stars in NGC 6231 (Sana+, 2008)
J/AJ/135/693 : X-ray and IR sources in RCW 108 (Wolk+, 2008)
J/MNRAS/398/221 : UBVIJHK photom. towards (l=305°,b=0°) (Baume+, 2009)
J/AJ/137/3210 : Chandra observations of h Persei (Currie+, 2009)
J/ApJS/186/191 : VI photometry & spectroscopy in h+χ Per (Currie+, 2010)
J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
J/A+A/531/A73 : NGC 6167 and NGC 6193 multi-photometry (Baume+, 2011)
J/A+A/532/A131 : New Galactic star clusters in VVV survey (Borissova+, 2011)
J/ApJS/194/2 : Chandra Carina Complex Project (CCCP) catalog (Broos+, 2011)
J/ApJS/194/14 : A Pan-Carina YSO catalog (Povich+, 2011)
J/ApJS/194/15 : CCCP: Carina's diffuse X-ray emission (Townsley+, 2011)
J/PASJ/64/107 : Multiwavelength study of NGC 281 complex (Sharma+, 2012)
J/A+A/555/A50 : UBVIc photometry of stars in Westerlund 2 (Carraro+, 2013)
J/MNRAS/435/2003 : G305 star-forming complex in 13CO (Hindson+, 2013)
J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)
J/AJ/145/125 : Spectroscopy & HST photom. in Westerlund 2 (Vargas+, 2013)
J/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)
J/A+A/564/A21 : Ammonia observations in G79.29+0.46 (Rizzo+, 2014)
J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)
J/MNRAS/446/3797 : Westerlund 2 UBVIc photometry (Hur+, 2015)
J/AJ/150/191 : IR photom. of YSOs in Cygnus-X DR15 (Rivera-Galvez+, 2015)
J/A+A/589/A113 : PMS stars in h Per (Argiroffi+, 2016)
J/A+A/596/A82 : X-ray study of the young cluster NGC6231 (Damiani+, 2016)
J/ApJS/224/4 : GOSSS III. Additional O-type systems (Maiz Apellaniz+, 2016)
J/MNRAS/455/1275 : Radial velocities of WR21a (Tramper+, 2016)
J/ApJ/843/33 : SOFIA Massive Star Formation Survey. I. (De Buizer+, 2017)
J/ApJS/229/28 : SFiNCs: X-ray, IR and membership catalogs (Getman+, 2017)
J/AJ/154/87 : Stellar population of NGC 6231 (Kuhn+, 2017)
J/A+A/608/A95 : GES: multi-line spectroscopic binary cand. (Merle+, 2017)
J/ApJ/864/136 : MSFRs multiwavelength study (Binder+, 2018)
J/ApJS/235/43 : 2nd MSFRs Omnibus X-ray Catalog (MOXC2) (Townsley+, 2018)
J/A+A/618/A93 : Gaia DR2 open clusters in the MW (Cantat-Gaudin+, 2018)
J/A+A/615/A148 : Pre-main sequence stars in Scorpius OB1 (Damiani, 2018)
J/A+A/620/A55 : Magnetic flaring from PMS stars spectra (Flaccomio+, 2018)
J/AJ/157/176 : X-ray emission from Gal. stellar bow shocks (Binder+, 2019)
Byte-by-byte Description of file: moxc3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- MSFR Name of the massive star-forming region
(REGIONNAME)
13- 20 A8 --- m_MSFR NGC 6193 has the same data as RCW 108-IR
22- 39 A18 --- CXOU X-ray source name
(HHMMSS.ss+DDMMSS.s; J2000) (Name)
41 A1 --- n_CXOU [p] p: source exhibiting photon pile-up;
column added by CDS (see Note 6)
43- 52 A10 --- Label X-ray source name used within the project (1)
54- 63 F10.6 deg RAdeg Right ascension (ICRS) (2)
65- 74 F10.6 deg DEdeg Declination (ICRS) (2)
76- 83 F8.6 arcsec ePos [0.002/3.5] 1σ error circle around
(RAdeg,DEdeg) (PosErr)
85-101 A17 --- PosType Algorithm used to estimate position
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Section 7.1)
(PosType)
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103-110 F8.6 --- no-m [0/0.01] Most valid probability; smallest of
ProbNoSrc_t, ProbNoSrc_s, ProbNoSrc_h,
ProbNoSrc_v (ProbNoSrc_MosValid) (3)
112-119 F8.6 --- no-t [0/0.4] Smallest p-value under the no-source
null hypothesis (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B
Section 4.3) among validaton merges;
total (0.5-7keV) energy bad
(ProbNoSrc_t) (3)
121-128 F8.6 --- no-s ? Smallest p-value under the no-source null
hypothesis among validation merges;
soft (0.5-2keV) energy ban
(ProbNoSrc_s) (3)
130-137 F8.6 --- no-h ? Smallest p-value under the no-source null
hypothesis among validation merges;
hard (2-7keV) energy band
(ProbNoSrc_h) (3)
139 I1 --- Val? Flag indicating that source validation
failed in all multi-ObsID merges; source
validation comes from a single ObsID
(IsOccasional)
--------------------------------------------------------------------------------
141-148 F8.6 --- KS_S ? Smallest p-value under the null hypothesis
(no variability within each single ObsID)
for the Kolmogorov-Smirnovtest on the
timestamps of each ObsID'sevent list
(ProbKS_single) (4)
150-157 F8.6 --- KS_M ? p-value under the null hypothesis (no
variability) for the Kolmogorov-Smirnov
test on the timestamps of he multi-ObsID
event list (ProbKS_merge) 4)
159-166 F8.6 --- Chi2 ? p-value under the null hypothesis (no
variability) for the χ2 test on the
single-ObsID measurements f PhotonFlux_t
(ProbChisq_PhotonFlux) (4)
--------------------------------------------------------------------------------
168-176 F9.2 s ExpNom [4691/625897] Total exposure time in merged
ObsIDs (ExposureTimeNominal)
178-185 F8.6 --- ExpFrac Fraction of ExposureTimeNominal that source
was observed (ExposureFraction) (5)
187-194 F8.6 ct Ct [1.6e-5/0.8] 0.5-8keV rate in 3x3 CCD
pixel cell in count/frame (RateIn3x3Cell) (6)
196 I1 --- Nobs [1/8] Total number of ObsIDs extracted
(NumObsIDs)
198 I1 --- Nph [1/8] Number of ObsIDs merged to estimate
photometry properties (NumMerged)
200-207 F8.6 --- Fdis Fraction of exposure discarded in merge
(MergeBias)
209-217 F9.6 arcmin b_theta Smallest off-axis angle for merged ObsIDs
(Theta_Lo)
219-227 F9.6 arcmin theta [0.03/20.6] Average off-axis angle for
merged ObsIDs
229-237 F9.6 arcmin B_theta Largest off-axis angle for merged ObsIDs
(Theta_Hi)
239-246 F8.6 --- PSFf [0.37/1] Average PSF fraction (at 1.5keV)
for merged ObsIDs (PsfFraction)
248-259 F12.6 --- Area [0.7/16188] Average aperture area for merged
ObsIDs in (0.492arcsec)2 (SrcArea)
261-268 F8.6 --- aglow [0/0.5]? Suspected afterglow fraction,
0.50:8.00keV (AfterglowFraction) (7)
270-274 I5 ct Oct-t [2/29733] Observed total (0.5-8keV) counts
in merged apertures (SrcCounts_t)
276-280 I5 ct Oct-s [0/23663] Observed soft (0.5-2keV) counts
in merged apertures (SrcCounts_s)
282-286 I5 ct Oct-h [0/14236] Observed hard (2-8keV) counts in
merged apertures (SrcCounts_h)
288-298 F11.6 --- bgScl [0.8/4338] Scaling of the background
extraction (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B
Section 5.4) (BkgScaling)
300-304 I5 ct bgct-t [5/19643] Observed total (0.5-8keV) counts
in merged background regions (BkgCounts_t)
306-309 I4 ct bgct-s [0/4278] Observed soft (0.5-2keV) counts in
merged background regions (BkgCounts_s)
311-315 I5 ct bgct-h [0/15365] Observed hard (2-8keV) counts in
merged background regions (BkgCounts_h)
317-328 F12.6 ct Nct-t [0.4/29554] Total (0.5-8keV) net counts in
merged apertures (NetCounts_t)
330-341 F12.6 ct Nct-s [-13.6/23517] Soft (0.5-2keV) net counts in
merged apertures (NetCounts_s)
343-354 F12.6 ct Nct-h [-15.6/13595] Hard (2-8keV) net counts in
merged apertures (NetCounts_h)
356-367 F12.6 ct b_Nct-t 1σ lower bound on TNcts
(NetCountsLot) (8)
369-379 F11.5 ct B_Nct-t 1σ upper bound on TNcts
(NetCountsHit) (8)
381-392 F12.6 ct b_Nct-s ? 1σ lower bound on SNcts
(NetCountsLos) (8)
394-405 F12.6 ct B_Nct-s 1σ upper bound on SNcts
(NetCountsHis) (8)
407-418 F12.6 ct b_Nct-h ? 1σ lower bound on HNcts
(NetCountsLoh) (8)
420-431 F12.6 ct B_Nct-h 1σ upper bound on HNcts
(NetCountsHih) (8)
433-441 F9.5 cm2.ct/ph Area-t [9/242] Mean effective area
in cm2.count.photon-1,
total (0.5-8keV) energy bad
(MeanEffectiveArea_t) (9)
443-451 F9.5 cm2.ct/ph Area-s [6/379] Mean effective area
in cm2.count.photon-1,
soft (0.5-2keV) energy ban
(MeanEffectiveArea_s) (9)
453-461 F9.5 cm2.ct/ph Area-h [8.8/221] Mean effective area
in cm2.count.photon-1,
hard (2-8keV) energy band
(MeanEffectiveArea_h) (9)
463-468 F6.4 keV Emed-t [0.5/7.8] Total (0.5-8keV) median energy,
observed spectrum (MedianEnergy_t) (10)
470-475 F6.4 keV Emed-s [0.5/2]? Soft (0.5-2keV) median energy,
observed spectrum (MedianEnergy_s) (10)
477-482 F6.4 keV Emed-h [2/8]? Hard (2-8keV) median energy,
observed spectrum (MedianEnergy_h) (10)
484-495 E12.6 ph/cm2/s XFlx-t [1.2e-8/0.001] Total (0.5-8keV) apparent
photon flux (PhotonFlux_t) (11)
497-508 E12.6 ph/cm2/s XFlx-s [-3.5e-6/0.002] Soft (0.5-2keV) apparent
photon flux (PhotonFlux_s) (11)
510-521 E12.6 ph/cm2/s XFlx-h [-1.7e-6/0.0007] Hard (2-8keV) apparent
photon flux (PhotonFlux_h) (11)
523-534 E12.6 10-7W/cm2 EFlx-t Total (0.5-8keV) energy flux max
(EnergyFluxs,0)+max(EnergyFluxh,0)
in erg/cm2/s (EnergyFluxt) (11)
536-547 E12.6 10-7W/cm2 EFlx-s ? Soft (0.5-2keV) apparent energy flux
(EnergyFlux_s) (11)
549-560 E12.6 10-7W/cm2 EFlx-h ? Hard (2-8keV) apparent energy flux
(PhotonFluxh*MedianEnergyh*1.602E-09)
(EnergyFlux_h) (11)
--------------------------------------------------------------------------------
Note (1): Source "labels" identify each source during data analysis, as the
source position (and thus the Name) is subject to change.
Note (2): ACIS ObsIDs are shifted to align with our astrometric reference
catalog, the Two Micron All Sky Survey (2MASS; Skrutskie+ 2006, ),
which uses the ICRS coordinate system
(http://old.ipac.caltech.edu/2mass/releases/allsky/doc/sec4_6.html).
Note (3): Source significance quantities ("ProbNoSrc_*") are computed using
a predefined set of ObsID combinations which do not depend on the data
observed (MOXC2; Townsley+ 2018ApJS..235...43T 2018ApJS..235...43T Section 2.2.3).
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. The p-value of
the observed extraction under the no-source hypothesis is calculated
by the method described by Weisskopf+ (2007ApJ...657.1026W 2007ApJ...657.1026W Appendix A2),
which is derived under the assumption that X-ray extractions follow
Poisson distributions.
Note (4): See Broos+ (2010ApJ...714.1582B 2010ApJ...714.1582B Section 7.6) for a description of
the ProbKS_single and ProbKS_merge variability indices, and caveats
regarding possible spurious indications of variability using the
ProbKS_merge index. The ProbChisq_PhotonFlux variability index is the
p-value under the null hypothesis (no variability) for the standard χ2
test on the single-ObsID measurements of PhotonFlux_t.
The accuracy of the inter-ObsID variability metrics (ProbKS_merge and
ProbChisq_PhotonFlux) depends on the consistency of the effective area
curves for the extractions of the source. Sources observed with both
the ACIS-only and zeroth-order HETG configurations will often produce
spurious indications of inter-ObsID variability (because those
configurations have very different effective area curves). Inter-ObsID
variability metrics are proper p-values only when all observations of
the source have identical effective area curves.
Note (5): Due to dithering over inactive portions of the focal plane, a
Chandra source often is not observed during some fraction of the
nominal exposure time (http://cxc.harvard.edu/ciao/why/dither.html).
We report here the CIAO quantity "FRACEXPO" produced by the tool mkarf.
Note (6): ACIS suffers from a nonlinearity at high count rates known as photon
pile-up, which is described in MOXC1, MOXC2, and references therein.
Source properties in this table are not corrected for pile-up effects.
Column RateIn3x3Cell is an estimate of the observed count rate falling
on an event detection cell of size 3x3 ACIS pixels, centered on the
source position. When RateIn3x3Cell>0.05 (count/frame), the reported
source properties may be biased by pile-up effects. See Table 4 and
col. "n_CXOU" for a list of source extractions confirmed to have
significant pile-up.
Note (7): Some background events arising from an instrumental 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+ 2010ApJ...714.1582B 2010ApJ...714.1582B
Section 3). After extraction, we attempt to identify afterglow events
using the AE tool aeafterglowreport and report the fraction of
extracted events attributed to afterglow; see the AE manual.
Note (8): Confidence intervals (68%) for NetCounts quantities are estimated by
the CIAO tool aprates (http://asc.harvard.edu/ciao/ahelp/aprates.html).
Note (9): The Ancillary Response File (ARF) in ACIS data analysis represents
both the effective area of the Observatory and the fraction of the
observation time for which data were actually collected for the source
(column ExposureFraction).
Note (10): MedianEnergy is the median energy of extracted events, corrected
for background (Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Section 7.3). As an
uncalibrated property of the observed events, MedianEnergy depends on
the shape of the effective area curves for the extractions of the source.
Note (11): PhotonFlux=(NetCounts/MeanEffectiveArea/ExposureTimeNominal)
(Broos+ 2010ApJ...714.1582B 2010ApJ...714.1582B Section 7.4).
EnergyFlux=1.602x10-9(erg/keV)xPhotonFluxxMedianEnergy
(Getman+ 2010ApJ...708.1760G 2010ApJ...708.1760G Section 2.2).
Because MeanEffectiveArea depends on the shape of the effective area
curves for the extractions of the source, PhotonFlux and EnergyFlux
exhibit source-dependent calibration errors.
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- MSFR Massive star-forming region name
13- 18 F6.2 deg GLON Galactic longitude
20- 24 F5.2 deg GLAT Galactic latitude
26- 27 I2 h RAh Hour of right ascension (J2000) (1)
29- 30 I2 min RAm Minute of right ascension (J2000)
32- 35 F4.1 s RAs Second of right ascension (J2000)
37 A1 --- DE- Sign of declination (J2000) (1)
38- 39 I2 deg DEd Degree of declination (J2000) (1)
41- 42 I2 arcmin DEm Arcminute of declination (J2000)
44- 45 I2 arcsec DEs Arcsecond of declination (J2000)
47- 51 F5.3 kpc Dist [0.4/4.3] Distance from the literature or
estimated in this paper (2)
53- 56 F4.2 arcmin/pc Scale [0.8/8.6] Image scale assuming "Dist" value
58- 61 F4.1 mag Av [0.5/20] Average absorption (3)
63 A1 --- u_Exp [~] Uncertainty flag on Exp
64- 66 I3 ks Exp Nominal exposure time (4)
68 A1 --- f_Exp [a] Flag on Exp (5)
70- 74 F5.2 [10-7W] logLtc [28/30.7]? log of total band (0.5-8keV)
luminosity, corrected for extinction (6)
76- 78 F3.1 Msun M50 [0.1/1.5]? Limiting mass (7)
80- 83 I4 --- Nx [651/5269]? Total number of X-ray point
sources found across the entire mosaic
85- 94 A10 --- n_Nx Same number of X-ray sources and
observations as the MSFR cited in
this column
96-152 A57 --- r_Dist Reference(s)
--------------------------------------------------------------------------------
Note (1): Coordinates for the primary Chandra/ACIS observation of the MSFR,
similar to those shown in the Chandra X-ray Center's ChaSeR
observation search tool.
Note (2): Distance from the literature or estimated in this paper; citations
are given in Column "r_Dist". These are often derived from Gaia DR2 data
(Gaia Collaboration 2016, I/337 and 2018, I/345); exceptions are DR15
and Onsala 2S. Papers deriving Gaia distances make different
assumptions about DR2 systematics; we do not attempt to resolve these
differences.
Note (3): Approximate average absorption to the target, estimated from a
variety of literature sources. Most MSFRs have highly variable and
spatially complex obscuration, so this value should be used only as a
rough indicator.
Note (4): Typical exposure time for the main MSFR. Most mosaics have a wide
range of exposures; detailed exposure maps are shown in Section 4.
Note (5):
a = This time is shown as approximate because we are using the zeroth-order
image from an HETG observation, so the effective ACIS-only integration
time is energy dependent (1keV here).
Note (6): Rough limiting luminosity where the brighter half of the X-ray
population is sampled, using PIMMS simulations for a five-count pre-MS
star on-axis, with an apec plasma (kT=2.7keV) and 0.4*Z☉ abundances
(Preibisch+ 2005ApJS..160..401P 2005ApJS..160..401P).
Note (7): Limiting mass corresponding to "logLtc", where the brighter half of
the X-ray population is captured (Preibisch+ 2005ApJS..160..401P 2005ApJS..160..401P Figure 3).
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- MSFR MOXC3 MSFR as in Table 1
13- 22 A10 --- m_MSFR 3 MSFR have the same data as others;
see column n_Nx in Table 1
24- 41 A18 --- Target Chandra target (1)
43- 47 I5 --- ObsID [2540/19979] Chandra Observation
Identification (ObsID) number
49- 58 A10 "Y/M/D" Date Start UT date of the observation
60- 65 I6 s Exp [4695/148104] Exposure time (2)
67- 68 I2 h RAh On-axis hour of right ascension (J2000) (3)
70- 71 I2 min RAm On-axis minute of right ascension (J2000)
73- 77 F5.2 s RAs On-axis second of right ascension (J2000)
79 A1 --- DE- On-axis sign of declination (J2000) (3)
80- 81 I2 deg DEd On-axis degree of declination (J2000) (3)
83- 84 I2 arcmin DEm On-axis arcminute of declination (J2000)
86- 89 F4.1 arcsec DEs On-axis arcsecond of declination (J2000)
91- 93 I3 deg Roll [12/359] Observatory roll angle
95-104 A10 --- Config Configuration (4)
106-110 A5 --- Mode ACIS observing mode (5)
112-122 A11 --- PI Principal investigator (PI) of the observation
124-140 A17 --- TGAIN Abbreviated name of the ACIS time-dependent
gain file (6)
142-144 A3 --- OBF Version of the Optical Blocking Filter model (7)
146 A1 --- --- [(]
147-152 F6.3 pix Xsky Shift in right ascension
(in SKY pixel; 1 SKY pixel=0.492") (8)
153 A1 --- --- [,]
155-160 F6.3 pix Ysky Shift in declination
(in SKY pixel; 1 SKY pixel=0.492") (8)
161 A1 --- --- [)]
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Note (1): Name of the target in the Chandra Data Archive search and retrieval
tool ChaSeR (http://cda.harvard.edu/chaser/mainEntry.do).
Note (2): Exposure times are the net usable times after various filtering steps
are applied in the data reduction process. For the following ObsIDs,
we discarded exposure time as noted to remove periods of high
instrumental background: 3501 (2%), 6410 (3%). The time variability of
the ACIS background is discussed in Section 6.16.3 of the Chandra
Proposers' Observatory Guide (http://asc.harvard.edu/proposer/POG/)
and in the ACIS Background Memos at
http://asc.harvard.edu/cal/Acis/Cal_prods/bkgrnd/current/
Note (3): The on-axis position is the time-averaged location of the optical
axis (CIAO parameters RAPNT,DECPNT;
http://cxc.harvard.edu/ciao/faq/nomtargpnt.html).
Note (4): ACIS observations can take on three Chandra configurations:
I (optical axis on ACIS-I, no grating), S (optical axis on ACIS-S, no
grating), or H (optical axis on ACIS-S, HETG in place). The subset of
the ACIS CCD detectors enabled for the observation is listed in
parentheses; the layout of the 10 detectors (numbered 0-9 here) in the
ACIS focal plane is shown in Section 6.1 of the Chandra Proposers'
Observatory Guide (http://asc.harvard.edu/proposer/POG/).
Note (5): ACIS observing modes are described in Section 6.12 of the Chandra
Proposers' Observatory Guide (http://asc.harvard.edu/proposer/POG/).
Note (6): Abbreviated name of the ACIS time-dependent gain file used for
calibration of event energies, e.g.,
"2002-02-01N6" = "acisD2002-02-01t_gainN0006.fits"
Note (7): The version of the Optical Blocking Filter (OBF) model used for
calibration of Ancillary Response Files and exposure maps.
Note (8): The shift (in RA and DEC) applied to the ObsID's aspect file (via
the CIAO tool wcs_update) to achieve astrometric alignment, expressed
as (dx, dy) in the Chandra "SKY" coordinate system
(http://asc.harvard.edu/ciao/ahelp/coords.html).
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History:
From electronic version of the journal
References:
Townsley et al. MOXC1. 2014ApJS..213....1T 2014ApJS..213....1T Cat. J/ApJS/213/1
Townsley et al. MOXC2. 2018ApJS..235...43T 2018ApJS..235...43T Cat. J/ApJS/235/43
(End) Emmanuelle Perret [CDS] 19-Feb-2020