J/ApJ/838/61 Candidate X-ray OB stars in MYStIX regions (Povich+, 2017)
Candidate X-ray OB stars in MYStIX massive star-forming regions.
Povich M.S., Busk H.A., Feigelson E.D., Townsley L.K., Kuhn M.A.
<Astrophys. J., 838, 61-61 (2017)>
=2017ApJ...838...61P 2017ApJ...838...61P (SIMBAD/NED BibCode)
ADC_Keywords: Photometry, infrared ; Spectral types ; H II regions ;
Clusters, open ; Stars, OB ; Extinction ; X-ray sources
Keywords: HII regions; infrared: stars; open clusters and associations: general;
stars: early-type; stars: massive; X-rays: stars
Abstract:
Massive O-type and early B-type (OB) stars in the nearby Galaxy remain
incompletely cataloged due to high extinction, bright visible and
infrared nebular emission in H II regions, and high field star
contamination. These difficulties are alleviated by restricting the
search to stars with X-ray emission. Using the X-ray point sources
from the Massive Young Star-forming Complex Study in Infrared and
X-Rays (MYStIX) survey of OB-dominated regions, we identify 98 MYStIX
candidate OB (MOBc) stars by fitting their 1-8µm spectral energy
distributions (SEDs) with reddened stellar atmosphere models. We
identify 27 additional MOBc stars based on JHKS photometry of X-ray
stars lacking SED fitting. These candidate OB stars indicate that the
current census of stars earlier than B1, taken across the 18 MYStIX
regions studied, is less than 50% complete. We also fit the SEDs of
239 previously published OB stars to measure interstellar extinction
and bolometric luminosities, revealing six candidate massive binary
systems and five candidate O-type (super)giants. As expected,
candidate OB stars have systematically higher extinction than
previously published OB stars. Notable results for individual regions
include identification of the OB population of a recently discovered
massive cluster in NGC 6357, an older OB association in the M17
complex, and new massive luminous O stars near the Trifid Nebula. In
several relatively poorly studied regions (RCW 38, NGC 6334, NGC 6357,
Trifid, and NGC 3576), the OB populations may increase by factors of 2.
Description:
X-ray point source catalogs for the 18 Massive Young Star-forming
Complex Study in Infrared and X-Rays (MYStIX) regions studied here
were produced by Kuhn+ (2010, J/ApJ/725/2485 and 2013, J/ApJS/209/27)
and Townsley (2014+, J/ApJS/213/1) from archival Chandra Advanced CCD
Imaging Camera (ACIS) observations.
MYStIX JHKs NIR photometry was obtained from images taken with the
United Kingdom Infrared Telescope (UKIRT) Wide-field Camera or from
the Two-Micron All-Sky Survey (2MASS). See section 2 for further
details.
Spitzer MIR photometry at 3.6, 4.5, 5.8, and 8.0um was provided either
by the Galactic Legacy Mid-Plane Survey Extraordinaire (GLIMPSE;
Benjamin+ 2003PASP..115..953B 2003PASP..115..953B) or by Kuhn+ (2013, J/ApJS/209/29).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 44 18 MYStIX cluster data
table2.dat 224 328 Previously cataloged OB stars among MYStIX
Probable Complex Member (MPCMs)
table3.dat 142 98 Candidate X-ray-emitting OB stars from SED fitting
table4.dat 96 27 Secondary candidate X-ray-emitting OB stars
from NIR photometry
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
II/293 : GLIMPSE Source Catalog (I + II + 3D) (IPAC 2008)
V/116 : Galactic O star catalog (Maiz-apellaniz+, 2004)
V/125 : Photometry and Spectroscopy for Luminous Stars (Reed 2005)
VII/233 : The 2MASS Extended sources (IPAC/UMass, 2003-2006)
III/260 : General Catalogue of Ap and Am stars (Renson+ 2009)
II/319 : UKIDSS-DR9 LAS, GCS and DXS Surveys (Lawrence+ 2012)
III/274 : Galactic O-Star Spectroscopic Survey (Sota+, 2014)
J/ApJS/69/99 : NGC 6334 centers of star formation JHK photom. (Straw+ 1989)
J/ApJ/454/151 : OB Associations of the Northern Milky Way (Massey+ 1995)
J/A+A/395/499 : XMM observations in M8 and NGC6530 (Rauw+, 2002)
J/ApJ/598/375 : Chandra X-ray observations of NGC 2024 (Skinner+, 2003)
J/AJ/129/393 : UBV photometry in W3 (Oey+, 2005)
J/ApJ/643/965 : Spitzer photometry of the Trifid nebula (M20) (Rho+, 2006)
J/AJ/132/1100 : X-ray and IR sources in RCW 38 (Wolk+, 2006)
J/ApJS/169/353 : Chandra sources in M17 (Broos+, 2007)
J/ApJ/670/428 : Bubbles in the galactic disk. II. (Churchwell+, 2007)
J/AJ/134/999 : X-ray observations of NGC 2264 (Dahm+, 2007)
J/ApJS/168/100 : X-ray study of star-forming region NGC 6357 (Wang+, 2007)
J/AJ/135/693 : X-ray and IR sources in RCW 108 (Wolk+, 2008)
J/AJ/138/227 : Stellar clusters in NGC 6334 complex (Feigelson+, 2009)
J/ApJ/696/1278 : The extended star-forming environment of M17 (Povich+, 2009)
J/ApJ/708/1760 : Flux estimations of faint X-ray sources (Getman+, 2010)
J/ApJ/725/2485 : X-rays from the star-forming complex W40 (Kuhn+, 2010)
J/ApJS/194/4 : Classification of CCCP X-ray sources (Broos+, 2011)
J/ApJS/194/5 : Carina OB stars in the CCCP catalog (Gagne+, 2011)
J/ApJS/194/6 : Candidate X-ray emitting OB stars in Carina (Povich+, 2011)
J/ApJ/733/50 : Mid-IR photom. monitoring of the ONC (Morales-Calderon+, 2011)
J/A+A/527/A77 : NGC 1893 optical and NIR photometry (Prisinzano+, 2011)
J/ApJ/733/113 : IRAC observations of IC 1795 (Roccatagliata+, 2011)
J/ApJ/743/39 : Spitzer obs. of W3 molecular cloud (Rivera-Ingraham+, 2011)
J/ApJ/743/166 : X-ray and infra-red study of RCW 38 (Winston+, 2011)
J/A+A/538/A142 : OB stars in NGC 6334 and NGC 6357 (Russeil+, 2012)
J/A+A/550/A107 : RV catalogue of O stars in 30 Doradus (Sana+, 2013)
J/A+A/555/A83 : X-ray properties of HM1 and IC2944/2948 (Naze+, 2013)
J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)
J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)
J/ApJS/209/28 : MYStIX Wide-Field NIR data: crowded fields (King+, 2013)
J/ApJS/209/29 : MYStIX: Mid-IR 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)
J/ApJS/213/1 : The MSFRs Omnibus X-ray Catalog (MOXC) (Townsley+, 2014)
J/ApJ/787/107 : Spatial structure of young stellar clusters. I. (Kuhn+, 2014)
J/ApJ/813/42 : O and B type stars in W3: first results (Kiminki+, 2015)
J/ApJS/227/18 : Candidate stellar bowshock nebulae (Kobulnicky+, 2016)
J/A+A/594/A82 : XMM sources in IC 1805 (Rauw+, 2016)
J/ApJ/833/193 : MYStIX candidate protostars (Romine+, 2016)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Cluster MYStIX Cluster Name
16- 21 F6.2 deg GLON Galactic Longitude
23- 28 F6.2 deg GLAT Galactic Latitude
30- 34 F5.3 kpc Dist [0.4/3.6] Distance
36- 41 A6 --- ESpT Earliest spectral type
43- 44 I2 mag Av [12/42] Max visual extinction
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Cluster MYStIX Cluster Name
17- 34 A18 --- MPCM MPCM IAU source name (HHMMSS.ss+DDMMSS.s;
J2000), Broos+ (2013, J/ApJS/209/32)
35- 35 A1 --- m_MPCM [ab] Multiple MPCM name component
37- 63 A27 --- Star Simbad star name
65- 85 A21 --- SpT MK Spectral Type(s)
87- 88 I2 --- r_SpT Literature reference for spectral type (1)
90- 93 F4.1 kK Teff [15/44.5] SpT based effective temperature (2)
95- 99 F5.1 mag Av [0/39.6]? Total line-of-sight extinction
from SED fit
101-106 F6.2 [Lsun] logLbol [2.5/6.3]? log bolometric luminosity
from SED fit
107-113 A7 --- f_logLbol Flag on logLbol (3)
116-116 A1 --- Cat Spitzer source Catalog (4)
118-134 A17 --- Spitzer Spitzer source name (GLLL.llll+BB.bbbb)
136-140 F5.2 mag Jmag [4.7/19.3]? 2MASS or UKIRT J band magnitude
142-146 F5.2 mag Hmag [4.7/16.4]? 2MASS or UKIRT H band magnitude
148-148 A1 --- f_Hmag [*] * = Photometry datapoint excluded
from SED fit
156-160 F5.2 mag Ksmag [4.7/13.4]? 2MASS or UKIRT Ks band magnitude
162-166 F5.2 mag 3.6mag [5/12.6]? Spitzer/IRAC 3.6um band magnitude
168-168 A1 --- f_3.6mag [*] * = Photometry datapoint excluded
from SED fit
176-180 F5.2 mag 4.5mag [4.8/13]? Spitzer/IRAC 4.5um band magnitude
182-182 A1 --- f_4.5mag [*] * = Photometry datapoint excluded
from SED fit
189-193 F5.2 mag 5.8mag [3/12.1]? Spitzer/IRAC 5.8um band magnitude
195-195 A1 --- f_5.8mag [*] * = Photometry datapoint excluded
from SED fit
202-206 F5.2 mag 8.0mag [1/12.2]? Spitzer/IRAC 8.0um band magnitude
208-208 A1 --- f_8.0mag [*] * = Photometry datapoint excluded
from SED fit
215-217 A3 --- Ori Source of JHK mag in each band
(from "T"woMASS or "U"KIRT)
219-222 A4 --- XIRE X-ray/IR Excess flag(s) (5)
224 A1 --- SED SED Candidate flag (6)
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Note (1): Literature reference for spectral type as follows:
1 = Skiff (Cat. B/mk);
2 = Shuping et al. (2012AJ....144..116S 2012AJ....144..116S);
3 = Ellerbroek et al. (2012ASPC..464..351E 2012ASPC..464..351E);
4 = SIMBAD (Wenger et al. 2000A&AS..143....9W 2000A&AS..143....9W);
5 = Maiz Apellaniz et al. (2007ApJ...660.1480M 2007ApJ...660.1480M);
6 = Schulz et al. (1981A&A....95...94S 1981A&A....95...94S);
7 = Hoffmeister et al. (2008ApJ...686..310H 2008ApJ...686..310H);
8 = Chini et al. (1980A&A....91..186C 1980A&A....91..186C);
9 = Bik et al. (2012ApJ...744...87B 2012ApJ...744...87B);
10 = Hirsch et al. (2012ApJ...757..113H 2012ApJ...757..113H);
11 = Sota et al. (2011ApJS..193...24S 2011ApJS..193...24S, see III/274);
12 = Maiz Apellaniz et al. (2016ApJS..224....4M 2016ApJS..224....4M).
Note (2): From the Martins et al. (2005A&A...436.1049M 2005A&A...436.1049M) calibrations of Teff
vs. spectral type for O stars, extended to early B stars by Crowther
(2005IAUS..227..389C 2005IAUS..227..389C).
Note (3): Flags on bolometric luminosity as follows:
f = Star is significantly underluminous compared to theoretical
calibrations of luminosity versus spectral type, log(Lbol)(ST) -
log(Lbol)_SED ≳ 0.3 dex. Could indicate incorrect identification of
MIR source, confusion/saturation affecting IR photometry, inaccurate
published spectral type, or underestimate of distance to the star;
g = Star is significantly overluminous compared to theoretical
calibrations of luminosity versus spectral type, log(Lbol)_SED -
log(Lbol)(ST) ≳ 0.5 dex. Could indicate incorrect identification of
MIR source, unresolved multiple system, other confusion/saturation
affecting IR photometry, inaccurate published spectral type, or
overestimate of distance to the star;
h = No luminosity class specified with Spectral Type, but SED fitting
indicates supergiant star;
i = W3(OH) ionizing source SED was fit using the Robitaille et al.
(2006ApJS..167..256R 2006ApJS..167..256R) YSO models.
Note (4): The source of the Spitzer cataloged names and photometry as follows:
K = MYStIX MIR point source from K13 (Kuhn+, 2013, J/ApJS/209/29);
C = GLIMPSE pipeline point source from highly-reliable Catalog (see II/293);
A = GLIMPSE pipeline point source from more-complete Archive (see II/293).
Note (5): X-ray/IR Excess flags as follows:
X = MYStIX X-ray source;
Y = definite IR excess emission evident at λ≤4.5um. SED fitting
results for "Y" sources are reported only when the four JHKs+[3.6]
bands could be well-fit by photospheric models,
except where otherwise noted;
M = "marginal" IR excess emission (or systematics in photometry) affecting
the [5.8] and/or [8.0] IRAC bands. SED fitting of "M" sources always
exclude the [5.8] and [8.0] bands.
Note (6): If checked, star was among the 67 selected independently by our
procedure for identifying OB candidates among IR SEDs that were counterparts
to MYStIX X-ray sources. The remaining 128 MYStIX OB stars were not selected
because they lacked X-ray detections, had insufficient/poor MIR counterpart
photometry for SED fitting, or were less luminous than the B1 V equivalent
cutoff.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- MOBc MYStIX OB Candidate Name
13- 30 A18 --- MPCM MPCM IAU source name (HHMMSS.ss+DDMMSS.s;
J2000), Broos+ (2013, J/ApJS/209/32)
32- 35 F4.1 mag Av [2/40] Interstellar extinction,
assuming ZAMS object
37- 40 F4.1 kK Teff [25.7/44.1] Stellar effective temperature,
assuming ZAMS object
42- 44 F3.1 [Lsun] logLbol [4/6] Bolometric luminosity, assuming ZAMS object
46- 62 A17 --- Spitzer Spitzer MIR source name (GLLL.llll+BB.bbbb) (1)
64- 68 F5.2 mag Jmag [7.9/21.5]? 2MASS or UKIRT J band magnitude
70- 74 F5.2 mag Hmag [7/16.6]? 2MASS or UKIRT H band magnitude
76- 80 F5.2 mag Ksmag [6.9/14]? 2MASS or UKIRT Ks band magnitude
82- 86 F5.2 mag 3.6mag [6.9/13.7]? Spitzer/IRAC 3.6um band magnitude (1)
88- 92 F5.2 mag 4.5mag [6.7/13.7]? Spitzer/IRAC 4.5um band magnitude (1)
94- 98 F5.2 mag 5.8mag [6.6/13.7]? Spitzer/IRAC 5.8um band magnitude (1)
100-104 F5.2 mag 8.0mag [6.6/13.1]? Spitzer/IRAC 8.0um band magnitude (1)
106-106 A1 --- Ori Provenance of the NIR photometry ("T"woMASS or
"U"KIRT)
108-142 A35 --- Notes Other ID/Spectral type (2)
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Note (1): MIR source designation and 4 band photometry taken from
Kuhn+ (2013, J/ApJS/209/29) or GLIMPSE point-source archive (II/293).
Note (2): Notes on individual sources. As in Table 2, "M" denotes marginal
IR excess sources for which available [5.8] and [8.0] photometry was
excluded from SED fitting.
Classifications:
YSOc = YSO/T Tauri candidate;
OBc = photometric massive star candidate.
Spectral type references include:
1 = Wolk et al. (2006, J/AJ/132/1100);
2 = Rauw et al. (2002, J/A+A/395/499);
3 = Gvaramadze et al. (2011A&A...535A..29G 2011A&A...535A..29G);
4 = Wang et al. (2007, J/ApJS/168/100);
5 = Povich et al. (2009, J/ApJ/696/1278);
6 = SIMBAD (Wenger et al. 2000A&AS..143....9W 2000A&AS..143....9W);
7 = Reed (2003AJ....125.2531R 2003AJ....125.2531R);
8 = Kiminki et al. (2015, J/ApJ/813/42);
9 = Neckel (1984A&A...137...58N 1984A&A...137...58N);
10 = Prisinzano et al. (2011, J/A+A/527/A77);
11 = Renson & Manfroid (2009, III/260);
Bik15 = Spectroscopically confirmed OB star,
A. Bik, private communication, (2015);
WIRO = This paper -- new spectral type reported
from spectroscopic follow-up with WIRO;
Kuhn16 = Spectroscopic followup by Kuhn et al., in preparation.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- MOBc MYStIX OB Secondary Candidate Name
13- 30 A18 --- MPCM MPCM IAU source name (HHMMSS.ss+DDMMSS.s;
J2000), Broos+ (2013, J/ApJS/209/32)
32- 35 F4.1 mag Av [6/38]? Interstellar extinction,
assuming ZAMS object (1)
37- 41 F5.2 mag JMag [-4.5/-2.4]? Absolute J band magnitude,
assuming ZAMS object (1)
43- 47 F5.2 mag Jmag [8.2/18.7] 2MASS or UKIRT J band magnitude
49- 53 F5.2 mag Hmag [7.4/14.9] 2MASS or UKIRT H band magnitude
55- 59 F5.2 mag Ksmag [6.2/12.8] 2MASS or UKIRT Ks band magnitude
61- 64 F4.2 mag e_Jmag [0.01/0.06] Uncertainty in Jmag
66- 69 F4.2 mag e_Hmag [0.01/0.06] Uncertainty in Hmag
71- 74 F4.2 mag e_Ksmag [0/0.06] Uncertainty in Ksmag
76- 76 A1 --- Ori [TU] Provenance of the NIR photometry
(from "T"woMASS or "U"KIRT)
78- 96 A19 --- Notes Other ID/Spectral type (2)
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Note (1): Av and JMag magnitudes were derived by dereddening the observed J-H
color and J magnitude to the main sequence, assuming the distance to
each region listed in Table 1 (see the text). When the value is null
(blank), dereddening to the main sequence would produce JMag more
luminous than an O3 V star. This could occur for evolved, luminous stars
or unresolved binary/multiple systems, hence no intrinsic source colors
can be assumed for the NIR source and no JMag or Av values are reported.
Note (2): Notes on individual sources. Classifications:
YSOc = YSO/T Tauri candidate;
OBc = photometric massive star candidate.
Spectral type references:
Bik15 = A. Bik, private communication (2015);
1 = Davis & Smith (1996A&A...310..961D 1996A&A...310..961D);
2 = Winston et al. (2011, J/ApJ/743/166);
3 = Wolk et al. (2006, J/AJ/132/1100);
4 = Rivera-Ingraham et al. (2011, J/ApJ/743/39);
5 = Kiminki et al. (2015, J/ApJ/813/42)
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 27-Oct-2017