J/ApJ/806/231 MISFITS survey: HCO+ obs. of Spitzer YSOs (Heiderman+, 2015)
The Gould belt 'MISFITS' survey: the real solar neighborhood protostars.
Heiderman A., Evans II N.J.
<Astrophys. J., 806, 231 (2015)>
=2015ApJ...806..231H 2015ApJ...806..231H (SIMBAD/NED BibCode)
ADC_Keywords: Molecular clouds ; YSOs ; Surveys ; Millimetric/submm sources
Keywords: dust, extinction; galaxies: ISM; infrared: stars; ISM: clouds;
galaxies: star formation
Abstract:
We present an HCO+ J=3->2 survey of Class 0+I and Flat SED young
stellar objects (YSOs) found in the Gould Belt clouds by surveys with
Spitzer. Our goal is to provide a uniform Stage 0+I source indicator
for these embedded protostar candidates. We made single point HCO+
J=3->2 measurements toward the source positions at the CSO and APEX of
546 YSOs (89% of the Class 0+I + Flat SED sample). Using the criteria
from van Kempen et al. (2009, J/A+A/498/167), we classify sources as
Stage 0+I or bona fide protostars and find that 84% of detected
sources meet the criteria. We recommend a timescale for the evolution
of Stage 0+I (embedded protostars) of 0.54Myr. We find significant
correlations of HCO+ integrated intensity with α and Tbol
but not with Lbol. The detection fraction increases smoothly as a
function of α and Lbol, while decreasing smoothly with Tbol.
Using the Stage 0+I sources tightens the relation between protostars
and high extinction regions of the cloud; 89% of Stage I sources lie
in regions with AV>8mag. Class 0+I and Flat SED YSOs that are not
detected in HCO+ have, on average, a factor of ∼2 higher Tbol and
a factor of ∼5 lower Lbolthan YSOs with HCO+ detections. We find
less YSO contamination, defined as the number of undetected YSOs
divided by the total number surveyed, for sources with Tbol≲600K
and Lbol≳1L☉. The contamination percentage is >90% at
AV<4mag and decreases as AV increases.
Description:
Observations of the HCO+ J=3->2 transition were obtained with the
heterodyne receiver at the Caltech Submillimeter Observatory (CSO)
during runs in 2009 (June and December), 2010 (July and December),
2011 (July), and 2012 (June and September).
The most southerly clouds, Musca and Chamaeleon, were observed with
the APEX telescope in 2011 October.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 138 546 MIsidentified YSOs from SED FITS (MISFITS)
survey properties
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See also:
II/332 : c2d Spitzer final data release (DR4) (Evans+, 2003)
J/AJ/145/94 : Protostar luminosities from Spitzer surveys (Dunham+, 2013)
J/ApJ/764/133 : Auriga-California giant molecular cloud (Harvey+, 2013)
J/ApJ/745/19 : Binary systems in Taurus-Auriga (Kraus+, 2012)
J/ApJS/194/43 : YSOs candidates and knots in CrA cloud (Peterson+, 2011)
J/ApJ/715/671 : X-ray and IR emission from YSOs (Wolk+, 2010)
J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)
J/ApJS/185/198 : The Cepheus flare observed with IRAC and MIPS (Kirk+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/A+A/498/167 : Embedded sources in L 1688 (van Kempen+, 2009)
J/ApJS/179/249 : Low-luminosity embedded protostar population (Dunham+, 2008)
J/ApJS/177/551 : Spitzer c2d survey of Lupus dark clouds (Merin+, 2008)
J/ApJ/680/495 : Interstellar clouds in the Gould belt survey (Harvey+, 2008)
J/ApJ/676/427 : MIPS and IRAC data on ChaII PMS stars (Alcala+, 2008)
Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Cloud Cloud Name
15- 30 A16 --- Name Source Name (JHHMMSS.s+DDMMSS)
33- 34 I2 h RAh Hour of Right Ascension (J2000)
36- 37 I2 min RAm Minute of Right Ascension (J2000)
39- 43 F5.2 s RAs Second of Right Ascension (J2000)
45- 45 A1 --- DE- Sign of the Declination (J2000)
46- 47 I2 deg DEd Degree of Declination (J2000)
49- 50 I2 arcmin DEm Arcminute of Declination (J2000)
52- 56 F5.2 arcsec DEs Arcsecond of Declination (J2000)
58- 62 F5.2 --- alpha [-1.6/4.9]? Extinction corrected spectral
index (1)
64- 64 A1 --- l_MBdV1 ? Upper limit flag on MBdV1 (2)
65- 69 F5.2 K.km/s MBdV1 [0/30.3]? Integrated main beam HCO+ line
intensity
71- 74 F4.2 K.km/s e_MBdV1 [0.02/2.1]? Uncertainty in MBdV1
76- 80 F5.2 K.km/s MBdV2 [0/13.2]? Integrated main beam HCO+ line
intensity for second source component (3)
82- 85 F4.2 K.km/s e_MBdV2 [0.06/2.8]? Uncertainty in MBdV2 (3)
87- 91 F5.2 km/s V1 [-8.2/11]? Central line velocity at source
position
93- 96 F4.2 km/s e_V1 [0.01/0.4]? Uncertainty in V1
98-102 F5.2 km/s dV1 [0.1/5.3]? Width of V1 line
104-107 F4.2 km/s e_dV1 [0.02/0.8]? Uncertainty in dV1
109-113 F5.2 km/s V2 [-3.3/12.6]? Central line velocity of
second source component (3)
115-118 F4.2 km/s e_V2 [0/2.2]? Uncertainty in V2 (3)
120-124 F5.2 km/s dV2 [0.5/12.3]? Width of V2 line (3)
126-129 F4.2 km/s e_dV2 [0.02/3.3]? Uncertainty in dV2 (3)
131-134 F4.1 mag Av [0.7/37.6]? Extinction at source position
136-136 A1 --- Smm [NY] Submillimeter Flag (4)
138-138 A1 --- St [NY] Protostar Flag (5)
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Note (1): A null value for alpha indicates the YSO is a known Class I source
but does not have enough IR photometric points to calculate
the spectral index.
Note (2): Upper limits are computed as MBdV1 + 2 times the uncertainty in MBdV1.
Note (3): TmbV2 and V2 and related uncertainties are recorded if
the source has double peaked emission.
Note (4): Flag indicating that the protostar does (Y) or does not (N) have at
least one observed photometry point in the far-infrared or
submillimeter (70-850 microns).
Note (5): Flag indicating that the protostar meets (Y) or does not meet (N)
the HCO+ line emission criteria to be categorized as a physical
Stage 0+1 protostar.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Oct-2015