J/ApJ/833/193 MYStIX candidate protostars (Romine+, 2016)
Young stellar populations in MYStIX star-forming regions: candidate protostars.
Romine G., Feigelson E.D., Getman K.V., Kuhn M.A., Povich M.S.
<Astrophys. J., 833, 193-193 (2016)>
=2016ApJ...833..193R 2016ApJ...833..193R (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Photometry, infrared ; X-ray sources ; Surveys
Keywords: infrared: stars; protoplanetary disks; stars: formation;
stars: protostars; X-rays: stars
Abstract:
The Massive Young Star-Forming Complex in Infrared and X-ray (MYStIX)
project provides a new census on stellar members of massive
star-forming regions within 4kpc. Here the MYStIX Infrared Excess
catalog and Chandra-based X-ray photometric catalogs are mined to
obtain high-quality samples of Class I protostars using criteria
designed to reduce extragalactic and Galactic field star
contamination. A total of 1109 MYStIX Candidate Protostars (MCPs) are
found in 14 star-forming regions. Most are selected from
protoplanetary disk infrared excess emission, but 20% are found from
their ultrahard X-ray spectra from heavily absorbed magnetospheric
flare emission. Two-thirds of the MCP sample is newly reported here.
The resulting samples are strongly spatially associated with molecular
cores and filaments on Herschel far-infrared maps. This spatial
agreement and other evidence indicate that the MCP sample has high
reliability with relatively few "false positives" from contaminating
populations. But the limited sensitivity and sparse overlap among the
infrared and X-ray subsamples indicate that the sample is very
incomplete with many "false negatives." Maps, tables, and source
descriptions are provided to guide further study of star formation in
these regions. In particular, the nature of ultrahard X-ray
protostellar candidates without known infrared counterparts needs to
be elucidated.
Description:
The present study seeks protostars from the Massive Young Star-forming
complex in Infrared and X-ray (MYStIX) survey catalogs. We combine
objects with protostellar infrared SEDs and 4.5um excesses with X-ray
sources exhibiting ultrahard spectra denoting very heavy obscuration.
These criteria filter away nearly all of the older Class II-III stars
and contaminant populations, but give very incomplete samples. The
result is a list of 1109 protostellar candidates in 14 star-forming
regions. See sections 1 and 2 for further explanations.
The reliability of the catalog is strengthened because a large
majority (86%) are found to be associated with dense cores seen in
Herschel 500um maps that trace cold dust emission. However, the
candidate list requires more detailed study for confirmation and
cannot be viewed as an unbiased view of star formation in the clouds.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 46 14 MYStIX fields summary
table2.dat 123 1109 MYStIX candidate protostars
table3.dat 1002 415 Notes on individual MYStIX candidate protostars
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See also:
J/MNRAS/453/2006 : NGC 2264 SCUBA-2 observations (Buckle+, 2015)
J/ApJS/219/21 : Deep NIR survey toward Aquila. I. MHOs (Zhang+, 2015)
J/ApJ/802/60 : Structure of young stellar clusters. II. (Kuhn+, 2015)
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/MNRAS/437/1561 : DR 21 Chandra source catalogue (Rivilla+, 2014)
J/A+A/561/A12 : W3 Main JHKs photometry (Bik+, 2014)
J/ApJS/209/32 : Probable young stars in the MYStIX project (Broos+, 2013)
J/ApJS/209/31 : The MYStIX IR-Excess Source catalog (MIRES) (Povich+, 2013)
J/ApJS/209/30 : MYStIX project: Bayesian matching (Naylor+, 2013)
J/ApJS/209/29 : MYStIX: Mid-IR observations and catalogs (Kuhn+, 2013)
J/ApJS/209/28 : MYStIX Wide-Field NIR data: crowded fields (King+, 2013)
J/ApJS/209/27 : MYStIX: the Chandra X-ray sources (Kuhn+, 2013)
J/ApJ/779/113 : IR photometry of YSOs in the W40 region (Mallick+, 2013)
J/ApJ/778/96 : Spitzer and NEWFIRM observations of NGC 6334 (Willis+, 2013)
J/A+A/557/A29 : Young stellar clusters in the Rosette (Cambresy+, 2013)
J/ApJS/206/9 : New EGOs from Spitzer GLIMPSE II survey. I. (Chen+, 2013)
J/A+A/553/A48 : Near-infrared variability in RCW 38 (Doerr+, 2013)
J/ApJ/767/36 : APEX observations of HOPS protostars (Stutz+, 2013)
J/ApJ/743/166 : X-ray and infra-red study of RCW 38 (Winston+, 2011)
J/ApJ/743/39 : Spitzer obs. of W3 molecular cloud (Rivera-Ingraham+, 2011)
J/ApJ/725/2485 : X-rays from the star-forming complex W40 (Kuhn+, 2010)
J/AJ/140/1214 : NIR spectroscopic survey of class I YSOs (Connelley+, 2010)
J/AJ/140/968 : A cluster of compact radio sources in W40 (Rodriguez+, 2010)
J/ApJ/716/474 : The Rosette star-forming complex. III. (Wang+, 2010)
J/A+A/515/A55 : NGC 6334-NGC 6357 complex (Russeil+, 2010)
J/ApJS/188/123 : The Bolocam Galactic Plane Survey. II. (Rosolowsky+, 2010)
J/ApJ/714/L285 : YSO candidates in M17 SWex (Povich+, 2010)
J/ApJ/707/1 : Water and Methanol masers in NGC 6334I(N) (Brogan+, 2009)
J/AJ/138/1116 : A Spitzer view of NGC 2264 (Sung+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/AJ/138/227 : Stellar clusters in NGC 6334 complex (Feigelson+, 2009)
J/AJ/138/33 : VLT JHKs imaging of RCW 38 (Derose+, 2009)
J/ApJ/696/1278 : The extended star-forming environment of M17 (Povich+, 2009)
J/AJ/136/2391 : GLIMPSE Extended Green Objects catalog (Cyganowski+, 2008)
J/ApJ/685/1005 : Spitzer and high-mass star forming regions (Qiu+, 2008)
J/ApJS/169/353 : Chandra sources in M17 (Broos+, 2007)
J/ApJS/168/100 : X-ray study of star-forming region NGC 6357 (Wang+, 2007)
J/ApJ/654/347 : Chandra X-ray observations in Eagle Nebula. I. (Linsky+, 2007)
J/ApJ/654/338 : Spitzer photometry in W3 molecular cloud (Ruch+, 2007)
J/AJ/132/1100 : X-ray and IR sources in RCW 38 (Wolk+, 2006)
J/A+A/455/903 : ACIS-I observations of NGC 2264 (Flaccomio+, 2006)
J/ApJ/643/965 : Spitzer photometry of the Trifid nebula (M20) (Rho+, 2006)
J/AJ/128/1684 : NGC 2264: VRIHα photometry (Sung+, 2004)
J/ApJ/607/904 : Chandra obs. of Trifid nebula (Rho+, 2004)
J/AJ/127/2659 : CHANDRA observations of NGC 2264 (Ramirez+, 2004)
J/A+A/417/557 : Rotation + variability of PMS Stars in NGC 2264 (Lamm, 2004)
J/AJ/126/1423 : MSX 8.3um fluxes of star-forming regions (Kraemer+, 2003)
J/A+A/316/102 : JHK Photometry in NGC 6334 (Tapia+, 1996)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Field Region name
16- 18 I3 --- Np [5/180] Total number of MYStIX Candidate Protostar
(MCP) for this region
20- 22 I3 --- IR [2/112] Number of MIRES sources that satisfy
the infrared color constraint (1)
24- 25 I2 --- 4E [1/57] Number of MIRES sources that satisfy
the [4.5] excess constraint (1)
27- 28 I2 --- X [3/80] Subsample found from X-ray emission (1)
30- 32 I3 --- Cloud [5/142] Number of candidates associated with
dense cores and filaments
34- 35 I2 --- MPCM [4/77] Number of candidates previously listed
in our MPCM catalog (Broos+ 2013, J/ApJS/209/32)
37- 38 I2 --- Known [0/67] Number of candidates previously
identified by other researchers
40- 46 A7 --- Reg Abbreviated region name as used in protostar
candidate designations in tables 2 and 3;
column added by CDS
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Note (1): Subsample found from infrared excess, and subsample found from X-ray
emission using the selection rules of Section 2.2-2.3. Note that the
counts in column "Np" are typically less than the sum of the counts
in columns "IR"-"X", as some candidates are found with more than one
selection procedure.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [MCP]
5- 11 A7 --- Reg Region identifier
13- 15 I3 --- MCP [1/180] MYStIX Candidate Protostar number within Reg
17- 34 A18 --- MYStIX MYStIX catalog designation (1)
36- 44 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000) (2)
46- 55 F10.6 deg DEdeg Declination in decimal degrees (J2000) (2)
57- 57 A1 --- fMPCM [NY] MYStIX Probable Complex Member catalog flag (3)
59- 65 A7 --- fMCP MCP selection flag (4)
67- 67 A1 --- fHer [NY] Herschel SPIRE 500um coincidence flag (5)
69- 69 A1 --- SubCl Sub cluster identifier (6)
71- 73 F3.1 keV ME [1/6.4]? Median energy of the net counts in keV (7)
75- 79 F5.1 ct Cts [-0.2/966]? Net counts, extracted photons
minus local background (7)
81- 81 A1 --- l_Psrc Limit flag on Psrc
83- 88 F6.4 --- Psrc [0/0.03]? Probability of source non-existence (7)
90- 90 A1 --- l_Pvar Limit flag on Pvar
92- 97 F6.4 --- Pvar [0.0001/0.1]? Probability of constant X-ray count
rate during Chandra exposure(s) (7)
99-103 F5.2 mag [3.6] [6/18.2]? Spitzer/IRAC 3.6um magnitude from
Kuhn+ (2013, J/ApJS/209/29)
105-109 F5.2 mag [4.5] [4.4/17.1]? Spitzer/IRAC 4.5um magnitude from
Kuhn+ (2013, J/ApJS/209/29)
111-115 F5.2 mag [5.8] [2.3/15.4]? Spitzer/IRAC 5.8um magnitude from
Kuhn+ (2013, J/ApJS/209/29)
117-121 F5.2 mag [8.0] [1.5/14.8]? Spitzer/IRAC 8.0um magnitude from
Kuhn+ (2013, J/ApJS/209/29)
123 A1 --- T3 [Y/ ] Notes on individual source in Table 3?
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Note (1): Entries in galactic coordinates are from the MIRES catalog of
Povich+ (2013, J/ApJS/209/31; in Simbad),
and entries in celestial coordinates are from the X-ray catalogs of
Kuhn+ (2013, J/ApJS/209/29) and
Townsley+ (2014, J/ApJS/213/1; in Simbad)
Note (2): MPCM positions (fMPCM=Y) may be slightly offset (<1") as they
represent our best estimate from multiwavelength catalogs
(Broos+ 2013, J/ApJS/209/32). MPCM positions take precedence over
those given here, when available.
Note (3): Binary indicator whether the source appears in the MYStIX Probable
Complex Member catalog (Broos+ 2013, J/ApJS/209/32). MPCM sources are
located within the Chandra field of view (yellow polygons in Figure1)
and satisfy a probabilistic decision tree procedure described by
Broos et al.
Note (4): Origin(s) of the source's selection as a MYStIX Candidate Protostar
as follows:
IR = obtained from the infrared excess criterion (Section 2.3);
4E = obtained from the [4.5] excess criterion (Section 2.3);
X = obtained from the ultrahard X-ray source criteria (Section 2.2).
Note (5): Binary indicator whether the source lies on or near a dense dusty
core or filament in the Herschel SPIRE 500um map.
Note (6): For most sources in the MPCM catalog, this column gives the
subcluster identifier from the maximum likelihood mixture model
described by Kuhn+ (2014, J/ApJ/787/107). A subcluster identifier
(A, B, C, ...) indicates the source is part of a statistically
significant grouping of MPCM stars, while a
U identifier indicates the source lies in an unclustered environment.
Note (7): Obtained from the Chandra catalogs of Kuhn+ (2013, J/ApJS/209/27) and
Townsley+ (2014, J/ApJS/213/1). Small values of the probabilities
Psrc and Pvar (e.g., Pvar<0.001) denote highly significant detections
with variable X-ray emission. Note that the probability of source
existence does not scale in a simple fashion with net counts due to
variations in the point spread function across the Chandra field of
view.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [MCP]
5- 11 A7 --- Reg Region identifier
13- 15 I3 --- MCP [1/177] MYStIX Candidate Protostar number
within Reg
17-1002 A986 --- Notes Notes on individual objects
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Apr-2017