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Title: ALMA IMAGING OF MILLIMETER/SUBMILLIMETER CONTINUUM EMISSION IN ORION KL

Abstract

We have carried out high-resolution observations with the Atacama Large Millimeter/Submillimeter Array (ALMA) of continuum emission from the Orion Kleinmann–Low (KL) region. We identify 11 compact sources at ALMA band 6 (245 GHz) and band 7 (339 GHz), including the Hot Core, Compact Ridge, SMA1, IRc4, IRc7, and a radio source I (Source I). A spectral energy distribution (SED) of each source is determined by using previous 3 mm continuum emission data. Physical properties such as size, mass, hydrogen number density, and column density are discussed based on the dust graybody SED. Among 11 identified sources, Source I, a massive protostar candidate, is a dominant energy source in Orion KL. We extensively investigate its SED from centimeter to submillimeter wavelengths. The SED of Source I can be fitted with a single power-law index of 1.97, suggesting an optically thick emission. We employ the H{sup −} free–free emission as an opacity source of this optically thick emission. The temperature, density, and mass of the circumstellar disk associated with Source I are constrained by the SED of H{sup −} free–free emission. Still, the fitting result shows a significant deviation from the observed flux densities. Combined with the thermal dust graybody SED tomore » explain excess emission at higher frequency, a smaller power-law index of 1.60 for the H{sup −} free–free emission is obtained in the SED fitting. The power-law index smaller than two would suggest a compact source size or a clumpy structure unresolved with the present study. Future higher resolution observations with ALMA are essential to reveal more detailed spatial structure and physical properties of Source I.« less

Authors:
;  [1];  [2];  [3]
  1. National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181–8588 (Japan)
  2. Korea Astronomy and Space Science Institute, Hwaam-dong 61-1, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of)
  3. Chile Observatory, National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)
Publication Date:
OSTI Identifier:
22522082
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 801; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC DUST; DENSITY; EMISSION SPECTRA; ENERGY SPECTRA; FLUX DENSITY; GHZ RANGE; HYDROGEN; INDEXES; MASS; OPACITY; RESOLUTION; STARS; WAVELENGTHS

Citation Formats

Hirota, Tomoya, Honma, Mareki, Kim, Mi Kyoung, and Kurono, Yasutaka, E-mail: tomoya.hirota@nao.ac.jp. ALMA IMAGING OF MILLIMETER/SUBMILLIMETER CONTINUUM EMISSION IN ORION KL. United States: N. p., 2015. Web. doi:10.1088/0004-637X/801/2/82.
Hirota, Tomoya, Honma, Mareki, Kim, Mi Kyoung, & Kurono, Yasutaka, E-mail: tomoya.hirota@nao.ac.jp. ALMA IMAGING OF MILLIMETER/SUBMILLIMETER CONTINUUM EMISSION IN ORION KL. United States. doi:10.1088/0004-637X/801/2/82.
Hirota, Tomoya, Honma, Mareki, Kim, Mi Kyoung, and Kurono, Yasutaka, E-mail: tomoya.hirota@nao.ac.jp. Tue . "ALMA IMAGING OF MILLIMETER/SUBMILLIMETER CONTINUUM EMISSION IN ORION KL". United States. doi:10.1088/0004-637X/801/2/82.
@article{osti_22522082,
title = {ALMA IMAGING OF MILLIMETER/SUBMILLIMETER CONTINUUM EMISSION IN ORION KL},
author = {Hirota, Tomoya and Honma, Mareki and Kim, Mi Kyoung and Kurono, Yasutaka, E-mail: tomoya.hirota@nao.ac.jp},
abstractNote = {We have carried out high-resolution observations with the Atacama Large Millimeter/Submillimeter Array (ALMA) of continuum emission from the Orion Kleinmann–Low (KL) region. We identify 11 compact sources at ALMA band 6 (245 GHz) and band 7 (339 GHz), including the Hot Core, Compact Ridge, SMA1, IRc4, IRc7, and a radio source I (Source I). A spectral energy distribution (SED) of each source is determined by using previous 3 mm continuum emission data. Physical properties such as size, mass, hydrogen number density, and column density are discussed based on the dust graybody SED. Among 11 identified sources, Source I, a massive protostar candidate, is a dominant energy source in Orion KL. We extensively investigate its SED from centimeter to submillimeter wavelengths. The SED of Source I can be fitted with a single power-law index of 1.97, suggesting an optically thick emission. We employ the H{sup −} free–free emission as an opacity source of this optically thick emission. The temperature, density, and mass of the circumstellar disk associated with Source I are constrained by the SED of H{sup −} free–free emission. Still, the fitting result shows a significant deviation from the observed flux densities. Combined with the thermal dust graybody SED to explain excess emission at higher frequency, a smaller power-law index of 1.60 for the H{sup −} free–free emission is obtained in the SED fitting. The power-law index smaller than two would suggest a compact source size or a clumpy structure unresolved with the present study. Future higher resolution observations with ALMA are essential to reveal more detailed spatial structure and physical properties of Source I.},
doi = {10.1088/0004-637X/801/2/82},
journal = {Astrophysical Journal},
number = 2,
volume = 801,
place = {United States},
year = {Tue Mar 10 00:00:00 EDT 2015},
month = {Tue Mar 10 00:00:00 EDT 2015}
}