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Title: THE DISTRIBUTION OF MASS SURFACE DENSITIES IN A HIGH-MASS PROTOCLUSTER

Abstract

We study the probability distribution function (PDF) of mass surface densities, Σ, of infrared dark cloud (IRDC) G028.37+00.07 and its surrounding giant molecular cloud. This PDF constrains the physical processes, such as turbulence, magnetic fields, and self-gravity, that are expected to be controlling cloud structure and star formation activity. The chosen IRDC is of particular interest since it has almost 100,000 solar masses within a radius of 8 pc, making it one of the most massive, dense molecular structures known and is thus a potential site for the formation of a “super star cluster.” We study Σ in two ways. First, we use a combination of NIR and MIR extinction maps that are able to probe the bulk of the cloud structure up to Σ ∼ 1 g cm{sup −2}( A {sub V}≃ 200 mag). Second, we study the FIR and submillimeter dust continuum emission from the cloud utilizing Herschel -PACS and SPIRE images and paying careful attention to the effects of foreground and background contamination. We find that the PDFs from both methods, applied over a ∼20′(30 pc)-sized region that contains ≃1.5 × 10{sup 5} M {sub ⊙} and enclosing a minimum closed contour with Σ ≃ 0.013 gmore » cm{sup −2} ( A {sub V} ≃ 3 mag), shows a lognormal shape with the peak measured at Σ ≃ 0.021 g cm{sup −2} ( A {sub V}≃ 4.7 mag). There is tentative evidence for the presence of a high-Σ power-law tail that contains from ∼3% to 8% of the mass of the cloud material. We discuss the implications of these results for the physical processes occurring in this cloud.« less

Authors:
; ;  [1]; ;  [2]
  1. Department. of Astronomy, University of Florida, Gainesville, FL 32611 (United States)
  2. Max-Planck-Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)
Publication Date:
OSTI Identifier:
22654215
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 829; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CLOUDS; CONTAMINATION; DENSITY; DISTRIBUTION; DISTRIBUTION FUNCTIONS; DUSTS; EMISSION; GRAVITATION; MAGNETIC FIELDS; MASS; MOLECULAR STRUCTURE; PERTURBED ANGULAR CORRELATION; STAR CLUSTERS; STARS; TURBULENCE

Citation Formats

Lim, Wanggi, Tan, Jonathan C., Ma, Bo, Kainulainen, Jouni, and Butler, Michael J. THE DISTRIBUTION OF MASS SURFACE DENSITIES IN A HIGH-MASS PROTOCLUSTER. United States: N. p., 2016. Web. doi:10.3847/2041-8205/829/1/L19.
Lim, Wanggi, Tan, Jonathan C., Ma, Bo, Kainulainen, Jouni, & Butler, Michael J. THE DISTRIBUTION OF MASS SURFACE DENSITIES IN A HIGH-MASS PROTOCLUSTER. United States. doi:10.3847/2041-8205/829/1/L19.
Lim, Wanggi, Tan, Jonathan C., Ma, Bo, Kainulainen, Jouni, and Butler, Michael J. 2016. "THE DISTRIBUTION OF MASS SURFACE DENSITIES IN A HIGH-MASS PROTOCLUSTER". United States. doi:10.3847/2041-8205/829/1/L19.
@article{osti_22654215,
title = {THE DISTRIBUTION OF MASS SURFACE DENSITIES IN A HIGH-MASS PROTOCLUSTER},
author = {Lim, Wanggi and Tan, Jonathan C. and Ma, Bo and Kainulainen, Jouni and Butler, Michael J.},
abstractNote = {We study the probability distribution function (PDF) of mass surface densities, Σ, of infrared dark cloud (IRDC) G028.37+00.07 and its surrounding giant molecular cloud. This PDF constrains the physical processes, such as turbulence, magnetic fields, and self-gravity, that are expected to be controlling cloud structure and star formation activity. The chosen IRDC is of particular interest since it has almost 100,000 solar masses within a radius of 8 pc, making it one of the most massive, dense molecular structures known and is thus a potential site for the formation of a “super star cluster.” We study Σ in two ways. First, we use a combination of NIR and MIR extinction maps that are able to probe the bulk of the cloud structure up to Σ ∼ 1 g cm{sup −2}( A {sub V}≃ 200 mag). Second, we study the FIR and submillimeter dust continuum emission from the cloud utilizing Herschel -PACS and SPIRE images and paying careful attention to the effects of foreground and background contamination. We find that the PDFs from both methods, applied over a ∼20′(30 pc)-sized region that contains ≃1.5 × 10{sup 5} M {sub ⊙} and enclosing a minimum closed contour with Σ ≃ 0.013 g cm{sup −2} ( A {sub V} ≃ 3 mag), shows a lognormal shape with the peak measured at Σ ≃ 0.021 g cm{sup −2} ( A {sub V}≃ 4.7 mag). There is tentative evidence for the presence of a high-Σ power-law tail that contains from ∼3% to 8% of the mass of the cloud material. We discuss the implications of these results for the physical processes occurring in this cloud.},
doi = {10.3847/2041-8205/829/1/L19},
journal = {Astrophysical Journal Letters},
number = 1,
volume = 829,
place = {United States},
year = 2016,
month = 9
}
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