Distributed Low-Mass Star Formation in the IRDC G34.43+00.24

Abstract

We have used deep near-infrared observations with adaptive optics to discover a distributed population of low-mass protostars within the filamentary Infrared Dark Cloud G34.43+00.24. We use maps of dust emission at multiple wavelengths to determine the column density structure of the cloud. In combination with an empirically-verified model of the magnitude distribution of background stars, this column density map allows us to reliably determine overdensities of red sources that are due to embedded protostars in the cloud. We also identify protostars through their extended emission in K-band which comes from excited H2 in protostellar outflows or reflection nebulosity. We find a population of distributed low-mass protostars, suggesting that low-mass protostars may form earlier than, or contemporaneously with, high-mass protostars in such a filament. The low-mass protostellar population may also produce the narrow linewidth SiO emission observed in some clouds without high-mass protostars. Finally, we use a molecular line map of the cloud to determine the virial parameter per unit length along the filament and find that the highest mass protostars form in the most bound portion of the filament, as suggested by theoretical models.

15 pages, 16 figures. This version add internal hypertext links to references, figures and tables. Full quality version at http://www.astro.yale.edu/foster/papers/Foster_2014_DistributedSF.pdf

References in corpus (10)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The UKIDSS Galactic Plane Survey
• The WFCAM Science Archive
• The UKIRT Wide Field Camera ZYJHK Photometric System: Calibration from 2MASS
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• The Effects of Radiative Transfer on Low-Mass Star Formation
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• Molecular Outflows and a Mid-Infrared Census of the Massive Star-Formation Region Associated with IRAS 18507+0121
• Radioactive Probes of the Supernova-Contaminated Solar Nebula: Evidence that the Sun was Born in a Cluster
• Infrared Nebulae Around Young Stellar Objects

Cited by in corpus (20)

• Gravity, Magnetic Field, and Turbulence: Relative Importance and Impact on Fragmentation in the Infrared Dark Cloud G34.43+00.24
• Dense core properties in the Infrared Dark cloud G14.225-0.506 revealed by ALMA
• Investigating the structure and fragmentation of a highly filamentary IRDC
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). II: Molecular Outflows in the Extreme Early Stages of Protocluster Formation
• Evidence of high-mass star formation through multi-scale mass accretion in hub-filament-system clouds
• Massive and low-mass protostars in massive "starless" cores
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: 278 GHz Class I Methanol Masers
• SiO emission as a probe of Cloud-Cloud Collisions in Infrared Dark Clouds
• Similar complex kinematics within two massive, filamentary infrared dark clouds
• A multi-wavelength observation and investigation of six infrared dark clouds
• Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: DNC/HNC Ratio
• Mid-J CO Shock Tracing Observations of Infrared Dark Clouds III: SLED fitting
• Mid-J CO Shock Tracing Observations of Infrared Dark Clouds I
• Deuterium Fractionation across the Infrared Dark Cloud G034.77-00.55 interacting with the Supernova Remnant W44
• Study of the 13CO/C18O abundance ratio towards the filamentary infrared dark cloud IRDC 34.43+0.24
• Probing the Global Dust Properties and Cluster Formation Potential of the Giant Molecular Cloud G148.24+00.41
• ArTéMiS imaging of the filamentary infrared dark clouds G1.75-0.08 and G11.36+0.80: Dust-based physical properties of the clouds and their clumps
• An X-ray View of Two Infrared Dark Clouds G034.43+00.24 and G035.39-00.33
• CO Depletion in Infrared Dark Clouds