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Article: A search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395

TitleA search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395
Authors
KeywordsGalaxies: individual (NGC 4214, NGC 4395)
Galaxies: spiral
Galaxies: starburst
Radio continuum: galaxies
ISM: supernova remnants
Issue Date2005
PublisherAstronomical Observatory of Belgrade. The Journal's web site is located at http://saj.matf.bg.ac.rs/archive.html
Citation
Serbian Astronomical Journal, 2005, n. 170, p. 101-110 How to Cite?
AbstractWe present the results of a search for new candidate radio su­pernova remnants (SNRs) in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA) at the wavelengths of 3.5 cm, 6 cm and 20 cm for NGC 4214 and 6 cm and 20 cm for NGC 4395. These observations were analyzed as part of our ongoing search for candidate radio SNRs in nearby galaxies: the goal of this search is to prepare a large sample of candidate radio SNRs for the purpose of a robust statistical study of the properties of these sources. Based on our analysis, we have confirmed the nonthermal nature of the discrete radio sources α and β in NGC 4214 and classify these sources as candidate radio SNRs based on their positional coincidences with HII regions in that galaxy. We have measured the flux densities of the two candidate radio SNRs at each wavelength and calculated corresponding spectral indices: we have also measured flux densities of two other discrete radio sources in these galaxies - ρ in NGC 4214 and #3 in NGC 4395 which we suspect to be additional candidate radio SNRs based on their positional coincidences with other HII regions in these galaxies. However, the radio data presently available for these sources can­not confirm such a classification and additional observations are needed. We have also calculated the radio luminosities Lradio at the wavelength of 20 cm for these two candidate radio SNRs as well as the corresponding values for the minimum total energy Emin required to power these radio sources via synchrotron emission and the corresponding magnetic field strength Bmin. We have compared our mean calculated values for these properties with the mean values for populations of candidate radio SNRs in other starburst galaxies: while the values for Lradio and Bmin are roughly comparable to the values seen in other starburst galaxies, the mean value for Emin is higher than the mean value of any other starburst galaxy. Finally, we include these two candidate radio SNRs in a discussion of the Σ − D relation for extragalactic candidate radio SNRs and find that these sources are located on the shallower end of the master Σ − D relation for all extragalactic SNRs as derived by Urošević et al.(2005).
Persistent Identifierhttp://hdl.handle.net/10722/222412
ISSN
2015 Impact Factor: 0.429
2015 SCImago Journal Rankings: 0.111

 

DC FieldValueLanguage
dc.contributor.authorVukotić, B-
dc.contributor.authorBojicic, I-
dc.contributor.authorPannuti, TG-
dc.contributor.authorUrošević Dejan, V-
dc.date.accessioned2016-01-14T01:41:54Z-
dc.date.available2016-01-14T01:41:54Z-
dc.date.issued2005-
dc.identifier.citationSerbian Astronomical Journal, 2005, n. 170, p. 101-110-
dc.identifier.issn1450-698X-
dc.identifier.urihttp://hdl.handle.net/10722/222412-
dc.description.abstractWe present the results of a search for new candidate radio su­pernova remnants (SNRs) in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA) at the wavelengths of 3.5 cm, 6 cm and 20 cm for NGC 4214 and 6 cm and 20 cm for NGC 4395. These observations were analyzed as part of our ongoing search for candidate radio SNRs in nearby galaxies: the goal of this search is to prepare a large sample of candidate radio SNRs for the purpose of a robust statistical study of the properties of these sources. Based on our analysis, we have confirmed the nonthermal nature of the discrete radio sources α and β in NGC 4214 and classify these sources as candidate radio SNRs based on their positional coincidences with HII regions in that galaxy. We have measured the flux densities of the two candidate radio SNRs at each wavelength and calculated corresponding spectral indices: we have also measured flux densities of two other discrete radio sources in these galaxies - ρ in NGC 4214 and #3 in NGC 4395 which we suspect to be additional candidate radio SNRs based on their positional coincidences with other HII regions in these galaxies. However, the radio data presently available for these sources can­not confirm such a classification and additional observations are needed. We have also calculated the radio luminosities Lradio at the wavelength of 20 cm for these two candidate radio SNRs as well as the corresponding values for the minimum total energy Emin required to power these radio sources via synchrotron emission and the corresponding magnetic field strength Bmin. We have compared our mean calculated values for these properties with the mean values for populations of candidate radio SNRs in other starburst galaxies: while the values for Lradio and Bmin are roughly comparable to the values seen in other starburst galaxies, the mean value for Emin is higher than the mean value of any other starburst galaxy. Finally, we include these two candidate radio SNRs in a discussion of the Σ − D relation for extragalactic candidate radio SNRs and find that these sources are located on the shallower end of the master Σ − D relation for all extragalactic SNRs as derived by Urošević et al.(2005).-
dc.languageeng-
dc.publisherAstronomical Observatory of Belgrade. The Journal's web site is located at http://saj.matf.bg.ac.rs/archive.html-
dc.relation.ispartofSerbian Astronomical Journal-
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.subjectGalaxies: individual (NGC 4214, NGC 4395)-
dc.subjectGalaxies: spiral-
dc.subjectGalaxies: starburst-
dc.subjectRadio continuum: galaxies-
dc.subjectISM: supernova remnants-
dc.titleA search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395-
dc.typeArticle-
dc.identifier.emailBojicic, I: ibojicic@hku.hk-
dc.identifier.authorityBojicic, I=rp02020-
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.2298/SAJ0570101V-
dc.identifier.issue170-
dc.identifier.spage101-
dc.identifier.epage110-
dc.publisher.placeSerbia-

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