THE MASS DISTRIBUTION OF STARLESS AND PROTOSTELLAR CORES IN GOULD BELT CLOUDS

Using data from the SCUBA Legacy Catalogue (850 μm) and Spitzer Space Telescope (3.6–70 μm), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by Submillimeter Common-User Bolometer Array (SCUBA) as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) for the five clouds. We find best-fit slopes to the high-mass end of the CMFs of −1.26 ± 0.20, −1.22 ± 0.06, −0.95 ± 0.20, and −1.67 ± 0.72 for Ophiuchus, Taurus, Perseus, and Orion, respectively. Broadly, these slopes are each consistent with the −1.35 power-law slope of the Salpeter initial mass function at higher masses, but suggest some differences. We examine a variety of trends between these CMF shapes and their parent cloud properties, potentially finding a correlation between the high-mass slope and core temperature. We also find a trend between core mass and effective size, but we are very limited by sensitivity. We make similar comparisons between core mass and size with visual extinction (for AV ⩾ 3) and find no obvious trends. We also predict the numbers and mass distributions of cores that future surveys with SCUBA-2 may detect in each of these clouds.

[1]  R. Klein,et al.  THE EFFECTS OF RADIATIVE TRANSFER ON LOW-MASS STAR FORMATION , 2009, 0904.2004.

[2]  Ireland,et al.  THE SPITZER SURVEY OF INTERSTELLAR CLOUDS IN THE GOULD BELT. II. THE CEPHEUS FLARE OBSERVED WITH IRAC AND MIPS , 2009, 0903.4063.

[3]  J. Francesco,et al.  THE INITIAL CONDITIONS OF CLUSTERED STAR FORMATION. I. NH3 OBSERVATIONS OF DENSE CORES IN OPHIUCHUS , 2009, 0903.0690.

[4]  E. Young,et al.  DETECTION OF STAR FORMATION IN THE UNUSUALLY COLD GIANT MOLECULAR CLOUD G216-2.5 , 2009, 0902.3168.

[5]  C. Dullemond,et al.  Lack of PAH emission toward low-mass embedded young stellar objects , 2008, 0812.3664.

[6]  D. Padgett,et al.  THE SPITZER c2d LEGACY RESULTS: STAR-FORMATION RATES AND EFFICIENCIES; EVOLUTION AND LIFETIMES , 2008, 0811.1059.

[7]  N. Evans,et al.  PROPERTIES OF THE YOUNGEST PROTOSTARS IN PERSEUS, SERPENS, AND OPHIUCHUS , 2008, 0809.4012.

[8]  T. Megeath,et al.  The Orion Molecular Cloud 2/3 and NGC 1977 Regions , 2008, 0809.4006.

[9]  P. Myers Protostar Mass due to Infall and Dispersal , 2008, 0807.1270.

[10]  E. Rosolowsky,et al.  The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus , 2008, 0805.1075.

[11]  D. Johnstone,et al.  Current Star Formation in the Ophiuchus and Perseus Molecular Clouds: Constraints and Comparisons from Unbiased Submillimeter and Mid-Infrared Surveys. II. , 2008, 0805.0599.

[12]  Gopal Narayanan,et al.  Large-Scale Structure of the Molecular Gas in Taurus Revealed by High Linear Dynamic Range Spectral Line Mapping , 2008, 0802.2206.

[13]  J. Foster,et al.  An Ammonia Spectral Atlas of Dense Cores in Perseus , 2007, 0711.0231.

[14]  R. A. Gutermuth,et al.  Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster , 2007, 0710.1860.

[15]  D. Stamatellos,et al.  SCUBA and Spitzer observations of the Taurus molecular cloud – pulling the bull's tail , 2007, 0711.3565.

[16]  D. Padgett,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VII. Ophiuchus Observed with MIPS , 2007, 0709.3492.

[17]  G. Fazio,et al.  A Combined Spitzer and Chandra Survey of Young Stellar Objects in the Serpens Cloud Core , 2007, 0707.2537.

[18]  A. Whitworth,et al.  The James Clerk Maxwell Telescope Legacy Survey of Nearby Star‐forming Regions in the Gould Belt , 2007, 0707.0169.

[19]  B. Merín,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. IX. The Serpens YSO Population as Observed with IRAC and MIPS , 2007, 0704.0009.

[20]  D. Padgett,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. VIII. Serpens Observed with MIPS , 2007, astro-ph/0701711.

[21]  D. Ward-Thompson,et al.  A SCUBA survey of Orion -the low-mass end of the core mass function , 2006, astro-ph/0611164.

[22]  D. Johnstone,et al.  Current Star Formation in the Perseus Molecular Cloud: Constraints from Unbiased Submillimeter and Mid-Infrared Surveys , 2006, astro-ph/0610381.

[23]  G. Fuller,et al.  Star formation in Perseus: II. SEDs, classification and lifetimes , 2006, astro-ph/0612601.

[24]  S. Bontemps,et al.  A new view of the Cygnus X region - KOSMA $\mathsf{^{13}}$CO 2 $\to$ 1, 3 $\to$ 2, and $\mathsf{^{12}}$CO 3 $\to$ 2 imaging , 2006 .

[25]  D. Padgett,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. III. Perseus Observed with IRAC , 2006, astro-ph/0603547.

[26]  D. Johnstone,et al.  The Large- and Small-Scale Structures of Dust in the Star-forming Perseus Molecular Cloud , 2006, astro-ph/0602089.

[27]  E. F. Ladd,et al.  Star formation in Perseus - Clusters, filaments and the conditions for star formation , 2005 .

[28]  A. Goodman,et al.  A COMPLETE Look at the Use of IRAS Emission Maps to Estimate Extinction and Dust Temperature , 2005, astro-ph/0508042.

[29]  D. Padgett,et al.  The Spitzer c2d Survey of Large, Nearby, Interstellar Clouds. V. Chamaeleon II Observed with IRAC , 2005, astro-ph/0610849.

[30]  I. Bonnell,et al.  Centrally condensed turbulent cores: massive stars or fragmentation , 2005, Proceedings of the International Astronomical Union.

[31]  D. Froebrich Which Are the Youngest Protostars? Determining Properties of Confirmed and Candidate Class 0 Sources by Broadband Photometry , 2004, astro-ph/0410044.

[32]  K. Rice,et al.  Protostars and Planets V , 2005 .

[33]  Paul S. Smith,et al.  The Multiband Imaging Photometer for Spitzer (MIPS) , 2004 .

[34]  G. Fazio,et al.  Infrared Array Camera (IRAC) Colors of Young Stellar Objects , 2004 .

[35]  D. Johnstone,et al.  An Extinction Threshold for Protostellar Cores in Ophiuchus , 2004, astro-ph/0406640.

[36]  E. Wright,et al.  The Spitzer Space Telescope Mission , 2004, astro-ph/0406223.

[37]  L. Allen,et al.  Initial Results from the Spitzer Young Stellar Cluster Survey , 2004, astro-ph/0406008.

[38]  Gary J. Melnick,et al.  In-flight performance and calibration of the Infrared Array Camera (IRAC) for the Spitzer Space Telescope , 2004, SPIE Astronomical Telescopes + Instrumentation.

[39]  I. Bonnell,et al.  Massive star formation: nurture, not nature , 2004, astro-ph/0401059.

[40]  Zhi-Yun Li,et al.  Does Magnetic Levitation or Suspension Define the Masses of Forming Stars? , 2003, astro-ph/0311426.

[41]  A. Robin,et al.  A synthetic view on structure and evolution of the Milky Way , 2003, astro-ph/0401052.

[42]  E. al.,et al.  From molecular cores to planet-forming disks: An SIRTF legacy program , 2003, astro-ph/0305127.

[43]  B. Elmegreen Star Formation from Galaxies to Globules , 2001, astro-ph/0207114.

[44]  M. Lombardi,et al.  Mapping the interstellar dust with near-infrared observations: An optimized multi-band technique , 2001, astro-ph/0109135.

[45]  R. Cutri,et al.  Extinction with 2MASS: Star Counts and Reddening toward the North America and Pelican Nebulae , 2001, astro-ph/0201373.

[46]  D. Johnstone,et al.  Large-Area Mapping at 850 Microns. II. Analysis of the Clump Distribution in the ρ Ophiuchi Molecular Cloud , 2000 .

[47]  Christine D. Wilson,et al.  Large-Area Mapping at 850 Microns. I. Optimum Image Reconstruction from Chop Measurements , 2000 .

[48]  P. Goldsmith Molecular Depletion and Thermal Balance in Dark Cloud Cores , 2000 .

[49]  Alyson G. Wilson,et al.  Star formation from the small to the large scale , 2000 .

[50]  P. Gensheimer,et al.  Dense Cores in the Orion Molecular Cloud , 1999 .

[51]  T. Henning,et al.  Dust opacities in dense regions , 1995 .

[52]  Elizabeth A. Lada,et al.  Dust Extinction and Molecular Gas in the Dark Cloud IC 5146 , 1994 .

[53]  Leo Blitz,et al.  DETERMINING STRUCTURE IN MOLECULAR CLOUDS , 1994 .

[54]  G. J. Babu,et al.  Linear regression in astronomy. II , 1990 .

[55]  B. Warner THE INITIAL MASS FUNCTION AND THE OCCURRENCE OF STARS OF SMALL MASS , 1961 .

[56]  E. Salpeter The Luminosity function and stellar evolution , 1955 .