skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: FAR-INFRARED DETECTION OF NEUTRAL ATOMIC OXYGEN TOWARD THE HORSEHEAD NEBULA

Abstract

We present the first detection of the neutral atomic oxygen ({sup 3} P {sub 1}-{sup 3} P {sub 2} fine structure line at {approx}63 {mu}m) toward the Horsehead photodissociation region (PDR). The cloud has been mapped with the Spitzer Space Telescope at far-IR (FIR) wavelengths using the Multiband Imaging Photometer for Spitzer in the spectral energy distribution mode. The [O I]63 {mu}m line peaks at the illuminated edge of the cloud at A{sub V} {approx_equal} 0.1-0.5 (inward the gas becomes too cold and outward the gas density drops). The luminosity carried by the [O I]63 {mu}m line represents a significant fraction of the total FIR dust luminosity (I {sub 63}/I {sub FIR} {approx_equal} 4 x 10{sup -3}). We analyze the dust continuum emission and the nonlocal O I excitation and radiative transfer in detail. The observations are reproduced with a gas density of n {sub H} {approx_equal} 10{sup 4} cm{sup -3} and gas and dust temperatures of T{sub k} {approx_equal} 100 K and T{sub d} {approx_equal} 30 K. We conclude that the determination of the O I {sup 3} P{sub J} level populations and emergent line intensities at such 'low' densities is a complex non-LTE problem. FIR radiative pumping, [Omore » I]63 {mu}m subthermal emission, [O I]145 {mu}m suprathermal and even maser emission can occur and decrease the resulting [O I]63/145 intensity ratio. The Herschel Space Observatory, observing from {approx}55 to 672 {mu}m, will allow us to exploit the diagnostic power of FIR fine structure lines with unprecedented resolution and sensitivity.« less

Authors:
 [1];  [2];  [3]
  1. Centro de Astrobiologia (CSIC-INTA), Laboratorio de Astrofisica Molecular, Carretera de Ajalvir, Km 4. Torrejon de Ardoz, 28850 Madrid (Spain)
  2. Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)
  3. Institut d'Astrophysique Spatiale, Universite Paris-Sud, 91405 Orsay Cedex (France)
Publication Date:
OSTI Identifier:
21313028
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal (Online)
Additional Journal Information:
Journal Volume: 699; Journal Issue: 2; Other Information: DOI: 10.1088/0004-637X/699/2/L165; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1538-4357
Country of Publication:
United States
Language:
English
Subject:
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; EMISSION; ENERGY SPECTRA; EXCITATION; FINE STRUCTURE; LUMINOSITY; MASERS; NEBULAE; PHOTOLYSIS; PHOTOMETERS; RADIANT HEAT TRANSFER; TELESCOPES

Citation Formats

Goicoechea, Javier R, Compiegne, Mathieu, and Habart, Emilie. FAR-INFRARED DETECTION OF NEUTRAL ATOMIC OXYGEN TOWARD THE HORSEHEAD NEBULA. United States: N. p., 2009. Web. doi:10.1088/0004-637X/699/2/L165; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Goicoechea, Javier R, Compiegne, Mathieu, & Habart, Emilie. FAR-INFRARED DETECTION OF NEUTRAL ATOMIC OXYGEN TOWARD THE HORSEHEAD NEBULA. United States. https://doi.org/10.1088/0004-637X/699/2/L165; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Goicoechea, Javier R, Compiegne, Mathieu, and Habart, Emilie. 2009. "FAR-INFRARED DETECTION OF NEUTRAL ATOMIC OXYGEN TOWARD THE HORSEHEAD NEBULA". United States. https://doi.org/10.1088/0004-637X/699/2/L165; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21313028,
title = {FAR-INFRARED DETECTION OF NEUTRAL ATOMIC OXYGEN TOWARD THE HORSEHEAD NEBULA},
author = {Goicoechea, Javier R and Compiegne, Mathieu and Habart, Emilie},
abstractNote = {We present the first detection of the neutral atomic oxygen ({sup 3} P {sub 1}-{sup 3} P {sub 2} fine structure line at {approx}63 {mu}m) toward the Horsehead photodissociation region (PDR). The cloud has been mapped with the Spitzer Space Telescope at far-IR (FIR) wavelengths using the Multiband Imaging Photometer for Spitzer in the spectral energy distribution mode. The [O I]63 {mu}m line peaks at the illuminated edge of the cloud at A{sub V} {approx_equal} 0.1-0.5 (inward the gas becomes too cold and outward the gas density drops). The luminosity carried by the [O I]63 {mu}m line represents a significant fraction of the total FIR dust luminosity (I {sub 63}/I {sub FIR} {approx_equal} 4 x 10{sup -3}). We analyze the dust continuum emission and the nonlocal O I excitation and radiative transfer in detail. The observations are reproduced with a gas density of n {sub H} {approx_equal} 10{sup 4} cm{sup -3} and gas and dust temperatures of T{sub k} {approx_equal} 100 K and T{sub d} {approx_equal} 30 K. We conclude that the determination of the O I {sup 3} P{sub J} level populations and emergent line intensities at such 'low' densities is a complex non-LTE problem. FIR radiative pumping, [O I]63 {mu}m subthermal emission, [O I]145 {mu}m suprathermal and even maser emission can occur and decrease the resulting [O I]63/145 intensity ratio. The Herschel Space Observatory, observing from {approx}55 to 672 {mu}m, will allow us to exploit the diagnostic power of FIR fine structure lines with unprecedented resolution and sensitivity.},
doi = {10.1088/0004-637X/699/2/L165; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21313028}, journal = {Astrophysical Journal (Online)},
issn = {1538-4357},
number = 2,
volume = 699,
place = {United States},
year = {Fri Jul 10 00:00:00 EDT 2009},
month = {Fri Jul 10 00:00:00 EDT 2009}
}