J/AJ/144/31 Spitzer+2MASS photometry of protostar candidates (Kryukova+, 2012)
Luminosity functions of Spitzer-identified protostars in nine nearby molecular
clouds.
Kryukova E., Megeath S.T., Gutermuth R.A., Pipher J., Allen T.S.,
Allen L.E., Myers P.C., Muzerolle J.
<Astron. J., 144, 31 (2012)>
=2012AJ....144...31K 2012AJ....144...31K
ADC_Keywords: Molecular clouds ; YSOs ; Photometry, infrared
Keywords: infrared: stars - stars: formation - stars: protostars
stars: luminosity function, mass function
Abstract:
We identify protostars in Spitzer surveys of nine star-forming (SF)
molecular clouds within 1kpc: Serpens, Perseus, Ophiuchus, Chamaeleon,
Lupus, Taurus, Orion, Cep OB3, and Mon R2, which combined host over
700 protostar candidates. These clouds encompass a variety of SF
environments, including both low-mass and high-mass SF regions, as
well as dense clusters and regions of sparsely distributed star
formation. Our diverse cloud sample allows us to compare protostar
luminosity functions in these varied environments. We combine near-
and mid-infrared photometry from the Two Micron All Sky Survey and
Spitzer to create 1-24µm spectral energy distributions (SEDs).
Using protostars from the c2d survey with well-determined bolometric
luminosities, we derive a relationship between bolometric luminosity,
mid-IR luminosity (integrated from 1-24µm), and SED slope.
Estimations of the bolometric luminosities for protostar candidates
are combined to create luminosity functions for each cloud.
Contamination due to edge-on disks, reddened Class II sources, and
galaxies is estimated and removed from the luminosity functions. We
find that luminosity functions for high-mass SF clouds (Orion, Mon R2,
and Cep OB3) peak near 1L☉ and show a tail extending toward
luminosities above 100L☉. The luminosity functions of the
low-mass SF clouds (Serpens, Perseus, Ophiuchus, Taurus, Lupus, and
Chamaeleon) do not exhibit a common peak, however the combined
luminosity function of these regions peaks below 1L☉. Finally,
we examine the luminosity functions as a function of the local surface
density of young stellar objects. In the Orion molecular clouds, we
find a significant difference between the luminosity functions of
protostars in regions of high and low stellar density, the former of
which is biased toward more luminous sources. This may be the result
of primordial mass segregation, although this interpretation is not
unique. We compare our luminosity functions to those predicted by
models and find that our observed luminosity functions are best
matched by models that invoke competitive accretion, although we do
not find strong agreement between the high-mass SF clouds and any of
the models.
Description:
Aperture photometry of the IRAC data (Program IDs (PID) 43, 50, 30641,
50070) in Orion was taken from S. T. Megeath et al. (2012, in
preparation). The IRAC aperture photometry from Cep OB3 and Mon R2
(PID 20403) was taken from R. A. Gutermuth et al. (2012, in
preparation) with no modification.
Photometry for Serpens, Perseus, Ophiuchus, Chamaeleon, and Lupus were
obtained from the Cores to Disks (c2d) Spitzer Legacy project 4th
high-reliability data release (from
http://irsa.ipac.caltech.edu/data/SPITZER/C2D/).
We used Taurus photometry from the Spitzer Legacy Taurus Molecular
Cloud Survey data release S14 (from
http://ssc.spitzer.caltech.edu/spitzermission/observingprograms/legacy
/taurus/.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 144 728 Properties of protostar candidates
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
II/156 : IRAS Faint Source Catalog, |b|>10, Version 2.0 (Moshir+ 1989)
J/A+A/551/A46 : Compiled phot. for Cham I & II members (Lopez Marti+, 2013)
J/ApJ/733/50 : Mid-IR photometric monitoring of the ONC
(Morales-Calderon+, 2011)
J/ApJ/731/8 : Multiple star formation in Taurus-Auriga (Kraus+, 2011)
J/ApJS/196/4 : New young star candidates in Taurus-Auriga (Rebull+, 2011)
J/ApJ/727/64 : Young stellar groups & their most massive stars (Kirk+, 2011)
J/ApJ/714/778 : YSOs in the Serpens Molecular Cloud (Oliveira+, 2010)
J/AJ/139/950 : JHKs photometry in ONC (Robberto+, 2010)
J/A+A/513/A38 : RZJHK phot. for stellar sources in Serpens (Spezzi+, 2010)
J/ApJ/710/1247 : Dense cores in Gould Belt clouds (Sadavoy+, 2010)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/692/973 : Protostars in Perseus, Serpens and Ophiuchus (Enoch+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/AJ/137/4072 : Infrared photometry of G216-2.5 YSOs (Megeath+, 2009)
J/ApJS/184/18 : Spitzer survey of young stellar clusters (Gutermuth+, 2009)
J/ApJ/684/1240 : Prestellar cores in Perseus, Serpens, Ophiuchus (Enoch+, 2008)
J/ApJ/675/1375 : IRAC/MIPS photometry in Cha I (Luhman+, 2008)
J/ApJS/177/551 : Spitzer c2d survey of Lupus dark clouds (Merin+, 2008)
J/ApJ/676/427 : MIPS and IRAC data on ChaII PMS stars (Alcala+, 2008)
J/ApJ/683/822 : Star formation in Ophiuchus and Perseus II. (Jorgensen+, 2008)
J/ApJ/674/336 : Spitzer observations of NGC 1333 (Gutermuth+, 2008)
J/A+A/468/1009 : Star formation in Perseus. II. (Hatchell+, 2007)
J/ApJ/663/1149 : Spitzer survey of Serpens YSO population (Harvey+, 2007)
J/AJ/133/1560 : Spitzer c2d small clouds and cores (Wu+, 2007)
J/A+A/462/L17 : Dense cores in interstellar molecular clouds (Alves+, 2007)
J/ApJ/669/493 : Spitzer/Chandra YSOs in Serpens cloud core (Winston+, 2007)
J/ApJ/647/1180 : Infrared photometry of Taurus SFR (Luhman+, 2006)
J/AJ/129/1534 : Mid-IR photometry in the Orion Nebula (Robberto+, 2005)
J/ApJ/540/236 : KH photometry of Orion Nebula Cluster (Hillenbrand+, 2000)
J/AJ/116/1816 : JHKLMNOPQ photometry in Orion cluster (Hillenbrand+, 1998)
J/A+A/330/990 : VRIJHK phot. of the Serpens cloud core (Giovannetti+ 1998)
J/A+A/320/185 : UBVRIcJHKL photometry in Lup (Wichmann+ 1997)
J/AJ/109/709 : K survey of Ori A molecular cloud (Ali+ 1995)
J/ApJS/101/117 : UBVRIJHKLMNQ photometry in Taurus-Auriga (Kenyon+ 1995)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 A13 --- Name Protostar candidate location (3)
15 A1 --- r_Name Origin of position (1)
17- 18 I2 h RAh Hour of Right Ascension (J2000)
20- 21 I2 min RAm Minute of Right Ascension (J2000)
23- 27 F5.2 s RAs Second of Right Ascension (J2000)
29 A1 --- DE- Sign of the Declination (J2000)
30- 31 I2 deg DEd Degree of Declination (J2000)
33- 34 I2 arcmin DEm Arcminute of Declination (J2000)
36- 40 F5.2 arcsec DEs Arcsecond of Declination (J2000)
42- 46 F5.2 mag Jmag [9.25/17.74]? 2MASS J band magnitude
48- 51 F4.2 mag e_Jmag ? Uncertainty in Jmag
53- 57 F5.2 mag Hmag [6.76/16.59]? 2MASS H band magnitude
59- 62 F4.2 mag e_Hmag ? Uncertainty in Hmag
64- 68 F5.2 mag Kmag [5.15/16.1]? 2MASS Ks band magnitude
70- 73 F4.2 mag e_Kmag ? Uncertainty in Kmag
75- 79 F5.2 mag [3.6] [5.08/17.14]? Spitzer/IRAC 3.6um magnitude
81- 84 F4.2 mag e_[3.6] ? Uncertainty in [3.6]
86- 90 F5.2 mag [4.5] [4.05/17.55]? Spitzer/IRAC 4.5um magnitude
92- 95 F4.2 mag e_[4.5] ? Uncertainty in [4.5]
97-101 F5.2 mag [5.8] [2.13/15.12]? Spitzer/IRAC 5.8um magnitude
103-106 F4.2 mag e_[5.8] ? Uncertainty in [5.8]
108-112 F5.2 mag [8.0] [1.73/14.2]? Spitzer/IRAC 8.0um magnitude
114-117 F4.2 mag e_[8.0] ? Uncertainty in [8.0]
119-123 F5.2 mag [24] [-3.5/7.99] Spitzer/MIPS 24um magnitude
125-128 F4.2 mag e_[24] Uncertainty in [24]
130 A1 --- r_[24] Origin of [24] (2)
132-136 F5.2 --- alpha [-0.3/3.7] Spectral index α, best-fit of
log(λFλ)/logλ
137 A1 --- --- [0]
139-144 F6.3 [Lsun] logL Luminosity (log scale)
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Note (1): Flag on Name as follows:
a = Position determined from this work;
G = 2MASS and Spitzer/IRAC photometry from
Gutermuth et al. (2009, Cat. J/ApJS/184/18).
Note (2): Flag on 24mag as follows:
a = Photometry from this work;
b = Photometry from IRAS Faint Source Catalog (1989; Cat. II/156);
c = Photometry from IRAS Point Source Catalog (1986; Cat. II/125);
G = Spitzer/MIPS photometry
from Gutermuth et al. (2009, Cat. J/ApJS/184/18).
Note (3): the locations are: Orion; Cep OB3; Mon R2; Perseus; Serpens;
Ophiuchus; Taurus; Lupus I; Lupus III; Chamaeleon II.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Sylvain Guehenneux [CDS] 19-Sep-2013