Peculiar Dust Emission within the Orion Molecular Cloud
It is widely assumed that dust opacities in molecular clouds follow a power-law profile with an index, β . Recent studies of the Orion Molecular Cloud (OMC) 2/3 complex, however, show a flattening in the spectral energy distribution (SED) at λ > 2 mm, implying nonconstant indices on scales ≳0.08...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad93c7 |
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| author | Parisa Nozari Sarah Sadavoy Edwige Chapillon Brian Mason Rachel Friesen Ian Lowe Thomas Stanke James Di Francesco Thomas Henning Qizhou Zhang Amelia Stutz |
| author_facet | Parisa Nozari Sarah Sadavoy Edwige Chapillon Brian Mason Rachel Friesen Ian Lowe Thomas Stanke James Di Francesco Thomas Henning Qizhou Zhang Amelia Stutz |
| author_sort | Parisa Nozari |
| collection | DOAJ |
| description | It is widely assumed that dust opacities in molecular clouds follow a power-law profile with an index, β . Recent studies of the Orion Molecular Cloud (OMC) 2/3 complex, however, show a flattening in the spectral energy distribution (SED) at λ > 2 mm, implying nonconstant indices on scales ≳0.08 pc. The origin of this flattening is not yet known, but it may be due to the intrinsic properties of the dust grains or contamination from other sources of emission. We investigate the SED slopes in OMC 2/3 further using observations of six protostellar cores with Northern Extended Millimeter Array (NOEMA) from 2.9–3.6 mm and Atacama Large Millimeter/submillimeter Array (ALMA) Atacama Compact Array in Band 4 (1.9–2.1 mm) and Band 5 (1.6–1.8 mm) on core and envelope scales of ∼0.02–0.08 pc. We confirm flattened opacity indices between 2.9 mm and 3.6 mm for the six cores with β ≈ −0.16 to 1.45, which are notably lower than the β -values of >1.3 measured for these sources on 0.08 pc scales from single-dish data. Four sources have consistent SED slopes between the ALMA data and the NOEMA data. We propose that these sources may have a significant fraction of emission coming from large dust grains in embedded disks, which biases the emission more at longer wavelengths. Two sources, however, had inconsistent slopes between the ALMA and NOEMA data, indicating different origins of emission. These results highlight how care is needed when combining multiscale observations or extrapolating single-band observations to other wavelengths. |
| format | Article |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-bc1e08b0f3f4410e8c2a5f450371d55d2025-01-22T12:38:40ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01979214210.3847/1538-4357/ad93c7Peculiar Dust Emission within the Orion Molecular CloudParisa Nozari0Sarah Sadavoy1https://orcid.org/0000-0001-7474-6874Edwige Chapillon2https://orcid.org/0009-0003-6480-8084Brian Mason3https://orcid.org/0000-0002-8472-836XRachel Friesen4https://orcid.org/0000-0001-7594-8128Ian Lowe5https://orcid.org/0000-0003-4063-2646Thomas Stanke6https://orcid.org/0000-0002-5812-9232James Di Francesco7https://orcid.org/0000-0002-9289-2450Thomas Henning8https://orcid.org/0000-0002-1493-300XQizhou Zhang9https://orcid.org/0000-0003-2384-6589Amelia Stutz10https://orcid.org/0000-0003-2300-8200Queen’s University , 64 Bader Lane, Kingston, ON K7L3N6, CanadaQueen’s University , 64 Bader Lane, Kingston, ON K7L3N6, CanadaThe Institut de Radioastronomie Millimétrique (IRAM) , Grenoble, FranceNational Radio Astronomy Observatory , 520 Edgemont Road, Charlottesville, VA 22903, USADepartment of Astronomy & Astrophysics, University of Toronto , 50 St. George Street, Toronto, ON M5S 3H4, CanadaDepartment of Astronomy and Steward Observatory, University of Arizona , USAMax Planck Institute for Extraterrestrial Physics , Garching bei München, GermanyNRC Herzberg Astronomy and Astrophysics , 5071 West Saanich Road, Victoria, BC V9E 2E7, CanadaMax Planck Institute for Astronomy , Königstuhl 17, D-69117 Heidelberg, GermanyCenter for Astrophysics , Harvard & Smithsonian, 60 Garden Street, MS 42, Cambridge, MA 02138, USADepartamento de Astronomía, Universidad de Concepción , Casilla 160-C, Concepción, ChileIt is widely assumed that dust opacities in molecular clouds follow a power-law profile with an index, β . Recent studies of the Orion Molecular Cloud (OMC) 2/3 complex, however, show a flattening in the spectral energy distribution (SED) at λ > 2 mm, implying nonconstant indices on scales ≳0.08 pc. The origin of this flattening is not yet known, but it may be due to the intrinsic properties of the dust grains or contamination from other sources of emission. We investigate the SED slopes in OMC 2/3 further using observations of six protostellar cores with Northern Extended Millimeter Array (NOEMA) from 2.9–3.6 mm and Atacama Large Millimeter/submillimeter Array (ALMA) Atacama Compact Array in Band 4 (1.9–2.1 mm) and Band 5 (1.6–1.8 mm) on core and envelope scales of ∼0.02–0.08 pc. We confirm flattened opacity indices between 2.9 mm and 3.6 mm for the six cores with β ≈ −0.16 to 1.45, which are notably lower than the β -values of >1.3 measured for these sources on 0.08 pc scales from single-dish data. Four sources have consistent SED slopes between the ALMA data and the NOEMA data. We propose that these sources may have a significant fraction of emission coming from large dust grains in embedded disks, which biases the emission more at longer wavelengths. Two sources, however, had inconsistent slopes between the ALMA and NOEMA data, indicating different origins of emission. These results highlight how care is needed when combining multiscale observations or extrapolating single-band observations to other wavelengths.https://doi.org/10.3847/1538-4357/ad93c7Molecular cloudsInterstellar dustDust continuum emissionProtostarsRadio interferometry |
| spellingShingle | Parisa Nozari Sarah Sadavoy Edwige Chapillon Brian Mason Rachel Friesen Ian Lowe Thomas Stanke James Di Francesco Thomas Henning Qizhou Zhang Amelia Stutz Peculiar Dust Emission within the Orion Molecular Cloud The Astrophysical Journal Molecular clouds Interstellar dust Dust continuum emission Protostars Radio interferometry |
| title | Peculiar Dust Emission within the Orion Molecular Cloud |
| title_full | Peculiar Dust Emission within the Orion Molecular Cloud |
| title_fullStr | Peculiar Dust Emission within the Orion Molecular Cloud |
| title_full_unstemmed | Peculiar Dust Emission within the Orion Molecular Cloud |
| title_short | Peculiar Dust Emission within the Orion Molecular Cloud |
| title_sort | peculiar dust emission within the orion molecular cloud |
| topic | Molecular clouds Interstellar dust Dust continuum emission Protostars Radio interferometry |
| url | https://doi.org/10.3847/1538-4357/ad93c7 |
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