Bolocam Survey for 1.1 mm Dust Continuum Emission in the c2d Legacy Clouds. I. Perseus

Abstract

We have completed a 1.1 mm continuum survey of 7.5 deg2 of the PerseusMolecular Cloud using Bolocam at the Caltech Submillimeter Observatory.This represents the largest millimeter or submillimeter continuummap of Perseus to date. Our map covers more than 30,000 31" (FWHM)resolution elements to a 1 σ rms of 15 mJy beam-1. We detect a totalof 122 cores above a 5 σ point-source mass detection limit of 0.18Msolar, assuming a dust temperature of TD=10 K, 60 of which are newmillimeter or submillimeter detections. The 1.1 mm mass functionis consistent with a broken power law of slope α1=1.3 (0.5 Msolar 2.5 Msolar), similar to the local initial massfunction slope (α1=1.6, M<1 Msolar α2=2.7, M>1 Msolar). No more than5% of the total cloud mass is contained in discrete 1.1 mm cores,which account for a total mass of 285 Msolar. We suggest an extinctionthreshold for millimeter cores of AV~5 mag, based on our calculationof the probability of finding a 1.1 mm core as a function of AV.Much of the cloud is devoid of compact millimeter emission; despitethe significantly greater area covered compared to previous surveys,only 5-10 of the newly identified sources lie outside previouslyobserved areas. The two-point correlation function confirms thatdense cores in the cloud are highly structured, with significantclustering on scales as large as 2×105 AU. Our 1.1 mm emission surveyreveals considerably denser, more compact material than maps in othercolumn density tracers such as 13CO and AV, although the generalmorphologies are roughly consistent. These 1.1 mm results, especiallywhen combined with recently acquired c2d Spitzer Legacy data, willprovide a census of dense cores and protostars in Perseus and improveour understanding of the earliest stages of star formation in molecularclouds.