Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz

2015
journal article
article
35
cris.lastimport.wos2024-04-10T00:40:09Z
dc.abstract.enContext. 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 ($\sigma = 0.15 mJy/beam$) 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.pl
dc.affiliationWydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut – Obserwatorium Astronomicznepl
dc.contributor.authorVarenius, E.pl
dc.contributor.authorConway, J. E.pl
dc.contributor.authorMartí-Vidal, I.pl
dc.contributor.authorBeswick, R.pl
dc.contributor.authorDeller, A. T.pl
dc.contributor.authorWucknitz, O.pl
dc.contributor.authorJackson, N.pl
dc.contributor.authorAdebahr, B.pl
dc.contributor.authorPérez-Torres, M. A.pl
dc.contributor.authorChyży, Krzysztof - 100034 pl
dc.contributor.authorCarozzi, T. D.pl
dc.contributor.authorMoldón, J.pl
dc.contributor.authorAalto, S.pl
dc.contributor.authorBeck, R.pl
dc.contributor.authorBest, P.pl
dc.contributor.authorDettmar, R.-J.pl
dc.contributor.authorvan Driel, W.pl
dc.contributor.authorBrunetti, G.pl
dc.contributor.authorBrüggen, M.pl
dc.contributor.authorHaverkorn, M.pl
dc.contributor.authorHeald, G.pl
dc.contributor.authorHorellou, C.pl
dc.contributor.authorJarvis, M. J.pl
dc.contributor.authorMorabito, L. K.pl
dc.contributor.authorMiley, G. K.pl
dc.contributor.authorRöttgering, H. J. A.pl
dc.contributor.authorToribio, M. C.pl
dc.contributor.authorWhite, G. J.pl
dc.date.accessioned2015-07-16T16:51:34Z
dc.date.available2015-07-16T16:51:34Z
dc.date.issued2015pl
dc.date.openaccess12
dc.description.accesstimepo opublikowaniu
dc.description.additionalReproduced with permission from Astronomy & Astrophysics, © ESOpl
dc.description.versionostateczna wersja wydawcy
dc.description.volume574pl
dc.identifier.articleidA114pl
dc.identifier.doi10.1051/0004-6361/201425089pl
dc.identifier.eissn1432-0746pl
dc.identifier.issn0004-6361pl
dc.identifier.projectROD UJ / Ppl
dc.identifier.urihttp://ruj.uj.edu.pl/xmlui/handle/item/13112
dc.languageengpl
dc.language.containerengpl
dc.rightsUdzielam licencji. Uznanie autorstwa - Użycie niekomercyjne - Na tych samych warunkach 4.0 Międzynarodowa*
dc.rights.licenceOTHER
dc.rights.urihttp://creativecommons.org/licenses/by-nc-sa/4.0/legalcode.pl*
dc.share.typeotwarte czasopismo
dc.subject.entechniques: interferometricpl
dc.subject.entechniques: high angular resolutionpl
dc.subject.ensupernovae: individual: 2008izpl
dc.subject.engalaxies: starburstpl
dc.subject.engalaxies: individual: M82pl
dc.subject.engalaxies: star formationpl
dc.subtypeArticlepl
dc.titleSubarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHzpl
dc.title.journalAstronomy & Astrophysicspl
dc.typeJournalArticlepl
dspace.entity.typePublication
cris.lastimport.wos
2024-04-10T00:40:09Z
dc.abstract.enpl
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 ($\sigma = 0.15 mJy/beam$) 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.
dc.affiliationpl
Wydział Fizyki, Astronomii i Informatyki Stosowanej : Instytut – Obserwatorium Astronomiczne
dc.contributor.authorpl
Varenius, E.
dc.contributor.authorpl
Conway, J. E.
dc.contributor.authorpl
Martí-Vidal, I.
dc.contributor.authorpl
Beswick, R.
dc.contributor.authorpl
Deller, A. T.
dc.contributor.authorpl
Wucknitz, O.
dc.contributor.authorpl
Jackson, N.
dc.contributor.authorpl
Adebahr, B.
dc.contributor.authorpl
Pérez-Torres, M. A.
dc.contributor.authorpl
Chyży, Krzysztof - 100034
dc.contributor.authorpl
Carozzi, T. D.
dc.contributor.authorpl
Moldón, J.
dc.contributor.authorpl
Aalto, S.
dc.contributor.authorpl
Beck, R.
dc.contributor.authorpl
Best, P.
dc.contributor.authorpl
Dettmar, R.-J.
dc.contributor.authorpl
van Driel, W.
dc.contributor.authorpl
Brunetti, G.
dc.contributor.authorpl
Brüggen, M.
dc.contributor.authorpl
Haverkorn, M.
dc.contributor.authorpl
Heald, G.
dc.contributor.authorpl
Horellou, C.
dc.contributor.authorpl
Jarvis, M. J.
dc.contributor.authorpl
Morabito, L. K.
dc.contributor.authorpl
Miley, G. K.
dc.contributor.authorpl
Röttgering, H. J. A.
dc.contributor.authorpl
Toribio, M. C.
dc.contributor.authorpl
White, G. J.
dc.date.accessioned
2015-07-16T16:51:34Z
dc.date.available
2015-07-16T16:51:34Z
dc.date.issuedpl
2015
dc.date.openaccess
12
dc.description.accesstime
po opublikowaniu
dc.description.additionalpl
Reproduced with permission from Astronomy & Astrophysics, © ESO
dc.description.version
ostateczna wersja wydawcy
dc.description.volumepl
574
dc.identifier.articleidpl
A114
dc.identifier.doipl
10.1051/0004-6361/201425089
dc.identifier.eissnpl
1432-0746
dc.identifier.issnpl
0004-6361
dc.identifier.projectpl
ROD UJ / P
dc.identifier.uri
http://ruj.uj.edu.pl/xmlui/handle/item/13112
dc.languagepl
eng
dc.language.containerpl
eng
dc.rights*
Udzielam licencji. Uznanie autorstwa - Użycie niekomercyjne - Na tych samych warunkach 4.0 Międzynarodowa
dc.rights.licence
OTHER
dc.rights.uri*
http://creativecommons.org/licenses/by-nc-sa/4.0/legalcode.pl
dc.share.type
otwarte czasopismo
dc.subject.enpl
techniques: interferometric
dc.subject.enpl
techniques: high angular resolution
dc.subject.enpl
supernovae: individual: 2008iz
dc.subject.enpl
galaxies: starburst
dc.subject.enpl
galaxies: individual: M82
dc.subject.enpl
galaxies: star formation
dc.subtypepl
Article
dc.titlepl
Subarcsecond international LOFAR radio images of the M82 nucleus at 118 MHz and 154 MHz
dc.title.journalpl
Astronomy & Astrophysics
dc.typepl
JournalArticle
dspace.entity.type
Publication
Affiliations

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