Spitzer survey of the large magellanic cloud, surveying the agents of a galaxy's evolution (sage). IV. dust properties in the interstellar medium

Jean Philippe Bernard, William T. Reach, Deborah Paradis, Margaret Meixner, Roberta Paladini, Akiko Kawamura, Toshikazu Onishi, Uma Vijh, Karl Gordon, Remy Indebetouw, Joseph L. Hora, Barbara Whitney, Robert Blum, Marilyn Meade, Brian Babler, Ed B. Churchwell, Charles W. Engelbracht, Bi Qing For, Karl Misselt, Claus LeithererMartin Cohen, François Boulanger, Jay A. Frogel, Yasuo Fukui, Jay Gallagher, Varoujan Gorjian, Jason Harris, Douglas Kelly, William B. Latter, Suzanne Madden, Ciska Markwick-Kemper, Akira Mizuno, Norikazu Mizuno, Jeremy Mould, Antonella Nota, M. S. Oey, Knut Olsen, Nino Panagia, Pablo Perez-Gonzalez, Hiroshi Shibai, Shuji Sato, Linda Smith, Lister Staveley-Smith, A. G G M Tielens, Toshiya Ueta, Schuyler Van Dyk, Kevin Volk, Michael Werner, Dennis F Zaritsky

Research output: Contribution to journalArticle

125 Citations (Scopus)

Abstract

The goal of this paper is to present the results of a preliminary analysis of the extended infrared (IR) emission by dust in the interstellar medium (ISM) of the Large Magellanic Cloud (LMC). We combine Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and Infrared Astronomical Satellite (IRAS) data and correlate the infrared emission with gas tracers of H I, CO, and H α. We present a global analysis of the infrared emission as well as detailed modeling of the spectral energy distribution (SED) of a few selected regions. Extended emission by dust associated with the neutral, molecular, and diffuse ionized phases of the ISM is detected at all IR bands from 3.6 μm to 160 μm. The relative abundance of the various dust species appears quite similar to that in the Milky Way (MW) in all the regions we have modeled. We construct maps of the temperature of large dust grains. The temperature map shows variations in the range 12.1-34.7 K, with a systematic gradient from the inner to outer regions, tracing the general distribution of massive stars and individual H II regions as well as showing warmer dust in the stellar bar. This map is used to derive the far-infrared (FIR) optical depth of large dust grains. We find two main departures in the LMC with respect to expectations based on the MW: (1) excess mid-infrared (MIR) emission near 70 μm, referred to as the 70 μm excess, and (2) departures from linear correlation between the FIR optical depth and the gas column density, which we refer to as FIR excess emission. The 70 μm excess increases gradually from the MW to the LMC to the Small Magellanic Cloud (SMC), suggesting evolution with decreasing metallicity. The excess is associated with the neutral and diffuse ionized gas, with the strongest excess region located in a loop structure next to 30 Dor. We show that the 70 μm excess can be explained by a modification of the size distribution of very small grains with respect to that in the MW, and a corresponding mass increase of ≃13% of the total dust mass in selected regions. The most likely explanation is that the 70 μm excess is due to the production of large very small grains (VSG) through erosion of larger grains in the diffuse medium. This FIR excess could be due to intrinsic variations of the dust/gas ratio, which would then vary from 4.6 to 2.3 times lower than the MW values across the LMC, but X CO values derived from the IR emission would then be about three times lower than those derived from the Virial analysis of the CO data. We also investigate the possibility that the FIR excess is associated with an additional gas component undetected in the available gas tracers. Assuming a constant dust abundance in all ISM phases, the additional gas component would have twice the known H I mass. We show that it is plausible that the FIR excess is due to cold atomic gas that is optically thick in the 21 cm line, while the contribution by a pure H2 phase with no CO emission remains a possible explanation.

Original languageEnglish (US)
Pages (from-to)919-945
Number of pages27
JournalAstronomical Journal
Volume136
Issue number3
DOIs
StatePublished - Sep 1 2008

Fingerprint

Magellanic clouds
surveying
dust
galaxies
gas
gases
optical thickness
optical depth
tracers
tracer
astronomical satellites
cold gas
monatomic gases
H II regions
ionized gases
tracing
spectral energy distribution
massive stars
erosion
metallicity

Keywords

  • Galaxies: ISM
  • Infrared: galaxies
  • Infrared: ISM
  • ISM: abundances
  • ISM: clouds
  • Magellanic clouds

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Spitzer survey of the large magellanic cloud, surveying the agents of a galaxy's evolution (sage). IV. dust properties in the interstellar medium. / Bernard, Jean Philippe; Reach, William T.; Paradis, Deborah; Meixner, Margaret; Paladini, Roberta; Kawamura, Akiko; Onishi, Toshikazu; Vijh, Uma; Gordon, Karl; Indebetouw, Remy; Hora, Joseph L.; Whitney, Barbara; Blum, Robert; Meade, Marilyn; Babler, Brian; Churchwell, Ed B.; Engelbracht, Charles W.; For, Bi Qing; Misselt, Karl; Leitherer, Claus; Cohen, Martin; Boulanger, François; Frogel, Jay A.; Fukui, Yasuo; Gallagher, Jay; Gorjian, Varoujan; Harris, Jason; Kelly, Douglas; Latter, William B.; Madden, Suzanne; Markwick-Kemper, Ciska; Mizuno, Akira; Mizuno, Norikazu; Mould, Jeremy; Nota, Antonella; Oey, M. S.; Olsen, Knut; Panagia, Nino; Perez-Gonzalez, Pablo; Shibai, Hiroshi; Sato, Shuji; Smith, Linda; Staveley-Smith, Lister; Tielens, A. G G M; Ueta, Toshiya; Van Dyk, Schuyler; Volk, Kevin; Werner, Michael; Zaritsky, Dennis F.

In: Astronomical Journal, Vol. 136, No. 3, 01.09.2008, p. 919-945.

Research output: Contribution to journalArticle

Bernard, JP, Reach, WT, Paradis, D, Meixner, M, Paladini, R, Kawamura, A, Onishi, T, Vijh, U, Gordon, K, Indebetouw, R, Hora, JL, Whitney, B, Blum, R, Meade, M, Babler, B, Churchwell, EB, Engelbracht, CW, For, BQ, Misselt, K, Leitherer, C, Cohen, M, Boulanger, F, Frogel, JA, Fukui, Y, Gallagher, J, Gorjian, V, Harris, J, Kelly, D, Latter, WB, Madden, S, Markwick-Kemper, C, Mizuno, A, Mizuno, N, Mould, J, Nota, A, Oey, MS, Olsen, K, Panagia, N, Perez-Gonzalez, P, Shibai, H, Sato, S, Smith, L, Staveley-Smith, L, Tielens, AGGM, Ueta, T, Van Dyk, S, Volk, K, Werner, M & Zaritsky, DF 2008, 'Spitzer survey of the large magellanic cloud, surveying the agents of a galaxy's evolution (sage). IV. dust properties in the interstellar medium', Astronomical Journal, vol. 136, no. 3, pp. 919-945. https://doi.org/10.1088/0004-6256/136/3/919
Bernard, Jean Philippe ; Reach, William T. ; Paradis, Deborah ; Meixner, Margaret ; Paladini, Roberta ; Kawamura, Akiko ; Onishi, Toshikazu ; Vijh, Uma ; Gordon, Karl ; Indebetouw, Remy ; Hora, Joseph L. ; Whitney, Barbara ; Blum, Robert ; Meade, Marilyn ; Babler, Brian ; Churchwell, Ed B. ; Engelbracht, Charles W. ; For, Bi Qing ; Misselt, Karl ; Leitherer, Claus ; Cohen, Martin ; Boulanger, François ; Frogel, Jay A. ; Fukui, Yasuo ; Gallagher, Jay ; Gorjian, Varoujan ; Harris, Jason ; Kelly, Douglas ; Latter, William B. ; Madden, Suzanne ; Markwick-Kemper, Ciska ; Mizuno, Akira ; Mizuno, Norikazu ; Mould, Jeremy ; Nota, Antonella ; Oey, M. S. ; Olsen, Knut ; Panagia, Nino ; Perez-Gonzalez, Pablo ; Shibai, Hiroshi ; Sato, Shuji ; Smith, Linda ; Staveley-Smith, Lister ; Tielens, A. G G M ; Ueta, Toshiya ; Van Dyk, Schuyler ; Volk, Kevin ; Werner, Michael ; Zaritsky, Dennis F. / Spitzer survey of the large magellanic cloud, surveying the agents of a galaxy's evolution (sage). IV. dust properties in the interstellar medium. In: Astronomical Journal. 2008 ; Vol. 136, No. 3. pp. 919-945.
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abstract = "The goal of this paper is to present the results of a preliminary analysis of the extended infrared (IR) emission by dust in the interstellar medium (ISM) of the Large Magellanic Cloud (LMC). We combine Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and Infrared Astronomical Satellite (IRAS) data and correlate the infrared emission with gas tracers of H I, CO, and H α. We present a global analysis of the infrared emission as well as detailed modeling of the spectral energy distribution (SED) of a few selected regions. Extended emission by dust associated with the neutral, molecular, and diffuse ionized phases of the ISM is detected at all IR bands from 3.6 μm to 160 μm. The relative abundance of the various dust species appears quite similar to that in the Milky Way (MW) in all the regions we have modeled. We construct maps of the temperature of large dust grains. The temperature map shows variations in the range 12.1-34.7 K, with a systematic gradient from the inner to outer regions, tracing the general distribution of massive stars and individual H II regions as well as showing warmer dust in the stellar bar. This map is used to derive the far-infrared (FIR) optical depth of large dust grains. We find two main departures in the LMC with respect to expectations based on the MW: (1) excess mid-infrared (MIR) emission near 70 μm, referred to as the 70 μm excess, and (2) departures from linear correlation between the FIR optical depth and the gas column density, which we refer to as FIR excess emission. The 70 μm excess increases gradually from the MW to the LMC to the Small Magellanic Cloud (SMC), suggesting evolution with decreasing metallicity. The excess is associated with the neutral and diffuse ionized gas, with the strongest excess region located in a loop structure next to 30 Dor. We show that the 70 μm excess can be explained by a modification of the size distribution of very small grains with respect to that in the MW, and a corresponding mass increase of ≃13{\%} of the total dust mass in selected regions. The most likely explanation is that the 70 μm excess is due to the production of large very small grains (VSG) through erosion of larger grains in the diffuse medium. This FIR excess could be due to intrinsic variations of the dust/gas ratio, which would then vary from 4.6 to 2.3 times lower than the MW values across the LMC, but X CO values derived from the IR emission would then be about three times lower than those derived from the Virial analysis of the CO data. We also investigate the possibility that the FIR excess is associated with an additional gas component undetected in the available gas tracers. Assuming a constant dust abundance in all ISM phases, the additional gas component would have twice the known H I mass. We show that it is plausible that the FIR excess is due to cold atomic gas that is optically thick in the 21 cm line, while the contribution by a pure H2 phase with no CO emission remains a possible explanation.",
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TY - JOUR

T1 - Spitzer survey of the large magellanic cloud, surveying the agents of a galaxy's evolution (sage). IV. dust properties in the interstellar medium

AU - Bernard, Jean Philippe

AU - Reach, William T.

AU - Paradis, Deborah

AU - Meixner, Margaret

AU - Paladini, Roberta

AU - Kawamura, Akiko

AU - Onishi, Toshikazu

AU - Vijh, Uma

AU - Gordon, Karl

AU - Indebetouw, Remy

AU - Hora, Joseph L.

AU - Whitney, Barbara

AU - Blum, Robert

AU - Meade, Marilyn

AU - Babler, Brian

AU - Churchwell, Ed B.

AU - Engelbracht, Charles W.

AU - For, Bi Qing

AU - Misselt, Karl

AU - Leitherer, Claus

AU - Cohen, Martin

AU - Boulanger, François

AU - Frogel, Jay A.

AU - Fukui, Yasuo

AU - Gallagher, Jay

AU - Gorjian, Varoujan

AU - Harris, Jason

AU - Kelly, Douglas

AU - Latter, William B.

AU - Madden, Suzanne

AU - Markwick-Kemper, Ciska

AU - Mizuno, Akira

AU - Mizuno, Norikazu

AU - Mould, Jeremy

AU - Nota, Antonella

AU - Oey, M. S.

AU - Olsen, Knut

AU - Panagia, Nino

AU - Perez-Gonzalez, Pablo

AU - Shibai, Hiroshi

AU - Sato, Shuji

AU - Smith, Linda

AU - Staveley-Smith, Lister

AU - Tielens, A. G G M

AU - Ueta, Toshiya

AU - Van Dyk, Schuyler

AU - Volk, Kevin

AU - Werner, Michael

AU - Zaritsky, Dennis F

PY - 2008/9/1

Y1 - 2008/9/1

N2 - The goal of this paper is to present the results of a preliminary analysis of the extended infrared (IR) emission by dust in the interstellar medium (ISM) of the Large Magellanic Cloud (LMC). We combine Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and Infrared Astronomical Satellite (IRAS) data and correlate the infrared emission with gas tracers of H I, CO, and H α. We present a global analysis of the infrared emission as well as detailed modeling of the spectral energy distribution (SED) of a few selected regions. Extended emission by dust associated with the neutral, molecular, and diffuse ionized phases of the ISM is detected at all IR bands from 3.6 μm to 160 μm. The relative abundance of the various dust species appears quite similar to that in the Milky Way (MW) in all the regions we have modeled. We construct maps of the temperature of large dust grains. The temperature map shows variations in the range 12.1-34.7 K, with a systematic gradient from the inner to outer regions, tracing the general distribution of massive stars and individual H II regions as well as showing warmer dust in the stellar bar. This map is used to derive the far-infrared (FIR) optical depth of large dust grains. We find two main departures in the LMC with respect to expectations based on the MW: (1) excess mid-infrared (MIR) emission near 70 μm, referred to as the 70 μm excess, and (2) departures from linear correlation between the FIR optical depth and the gas column density, which we refer to as FIR excess emission. The 70 μm excess increases gradually from the MW to the LMC to the Small Magellanic Cloud (SMC), suggesting evolution with decreasing metallicity. The excess is associated with the neutral and diffuse ionized gas, with the strongest excess region located in a loop structure next to 30 Dor. We show that the 70 μm excess can be explained by a modification of the size distribution of very small grains with respect to that in the MW, and a corresponding mass increase of ≃13% of the total dust mass in selected regions. The most likely explanation is that the 70 μm excess is due to the production of large very small grains (VSG) through erosion of larger grains in the diffuse medium. This FIR excess could be due to intrinsic variations of the dust/gas ratio, which would then vary from 4.6 to 2.3 times lower than the MW values across the LMC, but X CO values derived from the IR emission would then be about three times lower than those derived from the Virial analysis of the CO data. We also investigate the possibility that the FIR excess is associated with an additional gas component undetected in the available gas tracers. Assuming a constant dust abundance in all ISM phases, the additional gas component would have twice the known H I mass. We show that it is plausible that the FIR excess is due to cold atomic gas that is optically thick in the 21 cm line, while the contribution by a pure H2 phase with no CO emission remains a possible explanation.

AB - The goal of this paper is to present the results of a preliminary analysis of the extended infrared (IR) emission by dust in the interstellar medium (ISM) of the Large Magellanic Cloud (LMC). We combine Spitzer Surveying the Agents of Galaxy Evolution (SAGE) and Infrared Astronomical Satellite (IRAS) data and correlate the infrared emission with gas tracers of H I, CO, and H α. We present a global analysis of the infrared emission as well as detailed modeling of the spectral energy distribution (SED) of a few selected regions. Extended emission by dust associated with the neutral, molecular, and diffuse ionized phases of the ISM is detected at all IR bands from 3.6 μm to 160 μm. The relative abundance of the various dust species appears quite similar to that in the Milky Way (MW) in all the regions we have modeled. We construct maps of the temperature of large dust grains. The temperature map shows variations in the range 12.1-34.7 K, with a systematic gradient from the inner to outer regions, tracing the general distribution of massive stars and individual H II regions as well as showing warmer dust in the stellar bar. This map is used to derive the far-infrared (FIR) optical depth of large dust grains. We find two main departures in the LMC with respect to expectations based on the MW: (1) excess mid-infrared (MIR) emission near 70 μm, referred to as the 70 μm excess, and (2) departures from linear correlation between the FIR optical depth and the gas column density, which we refer to as FIR excess emission. The 70 μm excess increases gradually from the MW to the LMC to the Small Magellanic Cloud (SMC), suggesting evolution with decreasing metallicity. The excess is associated with the neutral and diffuse ionized gas, with the strongest excess region located in a loop structure next to 30 Dor. We show that the 70 μm excess can be explained by a modification of the size distribution of very small grains with respect to that in the MW, and a corresponding mass increase of ≃13% of the total dust mass in selected regions. The most likely explanation is that the 70 μm excess is due to the production of large very small grains (VSG) through erosion of larger grains in the diffuse medium. This FIR excess could be due to intrinsic variations of the dust/gas ratio, which would then vary from 4.6 to 2.3 times lower than the MW values across the LMC, but X CO values derived from the IR emission would then be about three times lower than those derived from the Virial analysis of the CO data. We also investigate the possibility that the FIR excess is associated with an additional gas component undetected in the available gas tracers. Assuming a constant dust abundance in all ISM phases, the additional gas component would have twice the known H I mass. We show that it is plausible that the FIR excess is due to cold atomic gas that is optically thick in the 21 cm line, while the contribution by a pure H2 phase with no CO emission remains a possible explanation.

KW - Galaxies: ISM

KW - Infrared: galaxies

KW - Infrared: ISM

KW - ISM: abundances

KW - ISM: clouds

KW - Magellanic clouds

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