Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz
Context. The nuclear starburst in the nearby galaxy M82 provides an excellent laboratory for understanding the physics of star formation. This galaxy has been extensively observed in the past, revealing tens of radio-bright compact objects embedded in a diffuse free-free absorbing medium. Our unders...
| Autores: | , , , , , , , , , , , , , , , , , , , , , , , , , , , |
|---|---|
| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2015 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/387786 |
| Acceso en línea: | http://hdl.handle.net/10261/387786 |
| Access Level: | acceso abierto |
| Palabra clave: | Techniques: interferometric Techniques: high angular resolution Supernovae: individual: 2008iz Galaxies: starburst Galaxies: individual: M82 Galaxies: star formation |
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oai:digital.csic.es:10261/387786 |
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España |
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Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| title |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| spellingShingle |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz Varenius, E. Techniques: interferometric Techniques: high angular resolution Supernovae: individual: 2008iz Galaxies: starburst Galaxies: individual: M82 Galaxies: star formation |
| title_short |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| title_full |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| title_fullStr |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| title_full_unstemmed |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| title_sort |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHz |
| dc.creator.none.fl_str_mv |
Varenius, E. Conway, J. E. Martí-Vidal, I. Beswick, R. Deller, A. T. Wucknitz, O. Jackson, N. Adebahr, B. Pérez-Torres, Miguel A. Chyży, K. T. Carozzi, T. D. Moldón, J. Aalto, S. Beck, R. Best, P. Dettmar, R. -J. van Driel, W. Brunetti, G. Brüggen, M. Haverkorn, M. Heald, G. Horellou, C. Jarvis, M. J. Morabito, L. K. Miley, G. K. Röttgering, H. J. A. Toribio, M. C. White, G. J. |
| author |
Varenius, E. |
| author_facet |
Varenius, E. Conway, J. E. Martí-Vidal, I. Beswick, R. Deller, A. T. Wucknitz, O. Jackson, N. Adebahr, B. Pérez-Torres, Miguel A. Chyży, K. T. Carozzi, T. D. Moldón, J. Aalto, S. Beck, R. Best, P. Dettmar, R. -J. van Driel, W. Brunetti, G. Brüggen, M. Haverkorn, M. Heald, G. Horellou, C. Jarvis, M. J. Morabito, L. K. Miley, G. K. Röttgering, H. J. A. Toribio, M. C. White, G. J. |
| author_role |
author |
| author2 |
Conway, J. E. Martí-Vidal, I. Beswick, R. Deller, A. T. Wucknitz, O. Jackson, N. Adebahr, B. Pérez-Torres, Miguel A. Chyży, K. T. Carozzi, T. D. Moldón, J. Aalto, S. Beck, R. Best, P. Dettmar, R. -J. van Driel, W. Brunetti, G. Brüggen, M. Haverkorn, M. Heald, G. Horellou, C. Jarvis, M. J. Morabito, L. K. Miley, G. K. Röttgering, H. J. A. Toribio, M. C. White, G. J. |
| author2_role |
author author author author author author author author author author author author author author author author author author author author author author author author author author author |
| dc.contributor.none.fl_str_mv |
European Commission Science and Technology Facilities Council (UK) Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72] |
| dc.subject.none.fl_str_mv |
Techniques: interferometric Techniques: high angular resolution Supernovae: individual: 2008iz Galaxies: starburst Galaxies: individual: M82 Galaxies: star formation |
| topic |
Techniques: interferometric Techniques: high angular resolution Supernovae: individual: 2008iz Galaxies: starburst Galaxies: individual: M82 Galaxies: star formation |
| description |
Context. The nuclear starburst in the nearby galaxy M82 provides an excellent laboratory for understanding the physics of star formation. This galaxy has been extensively observed in the past, revealing tens of radio-bright compact objects embedded in a diffuse free-free absorbing medium. Our understanding of the structure and physics of this medium in M82 can be greatly improved by high-resolution images at low frequencies where the effects of free-free absorption are most prominent. Aims. The aims of this study are, firstly, to demonstrate imaging using international baselines of the Low Frequency Array (LOFAR), and secondly, to constrain low-frequency spectra of compact and diffuse emission in the central starburst region of M82 via high-resolution radio imaging at low frequencies. Methods. The international LOFAR telescope was used to observe M82 at 110-126 MHz and 146-162 MHz. Images were obtained using standard techniques from very long baseline interferometry. images were obtained at each frequency range: one only using international baselines, and one only using the longest Dutch (remote) baselines. Results. The 154 MHz image obtained using international baselines is a new imaging record in terms of combined image resolution (0.3′′) and sensitivity (σ = 0.15 mJy/beam) at low frequencies (<327 MHz). We detected 16 objects at 154 MHz, six of these also at 118 MHz. Seven objects detected at 154 MHz have not been catalogued previously. For the nine objects previously detected, we obtained spectral indices and emission measures by fitting models to spectra (combining LOFAR with literature data). Four weaker but resolved features are also found: a linear (50 pc) filament and three other resolved objects, of which two show a clear shell structure. We do not detect any emission from either supernova 2008iz or from the radio transient source 43.78+59.3. The images obtained using remote baselines show diffuse emission, associated with the outflow in M82, with reduced brightness in the region of the edge-on star-forming disk. © ESO, 2015. |
| publishDate |
2015 |
| dc.date.none.fl_str_mv |
2015 2025 2025 2025 |
| dc.type.none.fl_str_mv |
info:eu-repo/semantics/article http://purl.org/coar/resource_type/c_6501 Publisher's version info:eu-repo/semantics/publishedVersion |
| format |
article |
| status_str |
publishedVersion |
| dc.identifier.none.fl_str_mv |
http://hdl.handle.net/10261/387786 |
| url |
http://hdl.handle.net/10261/387786 |
| dc.language.none.fl_str_mv |
Inglés |
| language_invalid_str_mv |
Inglés |
| dc.relation.none.fl_str_mv |
#PLACEHOLDER_PARENT_METADATA_VALUE# info:eu-repo/grantAgreement/EC/FP7/283393 http://dx.doi.org/10.1051/0004-6361/201425089 Sí |
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info:eu-repo/semantics/openAccess |
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openAccess |
| dc.publisher.none.fl_str_mv |
EDP Sciences |
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EDP Sciences |
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reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC instname:Consejo Superior de Investigaciones Científicas (CSIC) |
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Consejo Superior de Investigaciones Científicas (CSIC) |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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DIGITAL.CSIC. Repositorio Institucional del CSIC |
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1869422451176243200 |
| spelling |
Subarcsecond international LOFAR radio images of the M82 nucleus at 118MHz and 154 MHzVarenius, E.Conway, J. E.Martí-Vidal, I.Beswick, R.Deller, A. T.Wucknitz, O.Jackson, N.Adebahr, B.Pérez-Torres, Miguel A.Chyży, K. T.Carozzi, T. D.Moldón, J.Aalto, S.Beck, R.Best, P.Dettmar, R. -J.van Driel, W.Brunetti, G.Brüggen, M.Haverkorn, M.Heald, G.Horellou, C.Jarvis, M. J.Morabito, L. K.Miley, G. K.Röttgering, H. J. A.Toribio, M. C.White, G. J.Techniques: interferometricTechniques: high angular resolutionSupernovae: individual: 2008izGalaxies: starburstGalaxies: individual: M82Galaxies: star formationContext. The nuclear starburst in the nearby galaxy M82 provides an excellent laboratory for understanding the physics of star formation. This galaxy has been extensively observed in the past, revealing tens of radio-bright compact objects embedded in a diffuse free-free absorbing medium. Our understanding of the structure and physics of this medium in M82 can be greatly improved by high-resolution images at low frequencies where the effects of free-free absorption are most prominent. Aims. The aims of this study are, firstly, to demonstrate imaging using international baselines of the Low Frequency Array (LOFAR), and secondly, to constrain low-frequency spectra of compact and diffuse emission in the central starburst region of M82 via high-resolution radio imaging at low frequencies. Methods. The international LOFAR telescope was used to observe M82 at 110-126 MHz and 146-162 MHz. Images were obtained using standard techniques from very long baseline interferometry. images were obtained at each frequency range: one only using international baselines, and one only using the longest Dutch (remote) baselines. Results. The 154 MHz image obtained using international baselines is a new imaging record in terms of combined image resolution (0.3′′) and sensitivity (σ = 0.15 mJy/beam) at low frequencies (<327 MHz). We detected 16 objects at 154 MHz, six of these also at 118 MHz. Seven objects detected at 154 MHz have not been catalogued previously. For the nine objects previously detected, we obtained spectral indices and emission measures by fitting models to spectra (combining LOFAR with literature data). Four weaker but resolved features are also found: a linear (50 pc) filament and three other resolved objects, of which two show a clear shell structure. We do not detect any emission from either supernova 2008iz or from the radio transient source 43.78+59.3. The images obtained using remote baselines show diffuse emission, associated with the outflow in M82, with reduced brightness in the region of the edge-on star-forming disk. © ESO, 2015.We acknowledge assistance by the LOFAR science support as well as Simon Casey for installing LOFAR software in Onsala. This research has made use of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. The research leading to these results has received funding from the European Commission Seventh Framework Programme (FP/2007−2013) under grant agreement No. 283393 (RadioNet3). e-MERLIN is the UK’s National Radio Interferometric facility, operated by the University of Manchester on behalf of the Science and Technology Facilities Council (STFC). LOFAR, the Low Frequency Array, designed and constructed by ASTRON, has facilities in several countries, that are owned by various parties (each with their own funding sources), and that are collectively operated by the International LOFAR Telescope (ILT) foundation under a joint scientific policy.EDP SciencesEuropean CommissionScience and Technology Facilities Council (UK)Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2025202520152025info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/387786reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/FP7/283393http://dx.doi.org/10.1051/0004-6361/201425089Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3877862026-05-22T06:33:51Z |
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15.811543 |