Skip navigation
Skip navigation

Search for synchrotron emission from secondary leptons in dense cold starless cores

Jones, D I; Protheroe, Raymond; Crocker, Roland

Description

We report radio continuum observations with the Australia Telescope Compact Array of two molecular clouds. The impetus for these observations is a search for synchrotron radiation by cosmic-ray secondary electrons/positrons in a region of enhanced density and possibly high magnetic field. We present modelling which shows that there should be an appreciable flux of synchrotron above the more diffuse, galactic synchrotron background. The starless core G333.1250.562 and infrared source...[Show more]

dc.contributor.authorJones, D I
dc.contributor.authorProtheroe, Raymond
dc.contributor.authorCrocker, Roland
dc.date.accessioned2015-12-13T22:55:16Z
dc.identifier.issn1323-3580
dc.identifier.urihttp://hdl.handle.net/1885/82455
dc.description.abstractWe report radio continuum observations with the Australia Telescope Compact Array of two molecular clouds. The impetus for these observations is a search for synchrotron radiation by cosmic-ray secondary electrons/positrons in a region of enhanced density and possibly high magnetic field. We present modelling which shows that there should be an appreciable flux of synchrotron above the more diffuse, galactic synchrotron background. The starless core G333.1250.562 and infrared source IRAS155965301 were observed at 1384 and 2368 MHz. For G333.1250.562, we find no significant levels of radio emission from this source at either frequency, nor any appreciable polarisation: we place an upper limit on the radio continuum flux from this source of 0.5 mJy beam -1 at both 1384 and 2368 MHz. Due to the higher than expected flux density limits, we also obtained archival ATCA data at 8640 MHz for this cloud and place an upper limit on the flux density of 50 Jy beam-1. Assuming the cosmic ray spectrum is similar to that near the Sun and given the cloud's molecular density and mass, we place an upper limit on the magnetic field of 500 G. IRAS 155965301, with an RMS of 50 Jy beam-1 at 1384 MHz, shows an HII region consistent with optically thin freefree emission already detected at 4800 MHz. We use the same prescription as G333 to constrain the magnetic field from this cloud to be less than 500 G. We find that these values are not inconsistent with the view that magnetic field values scale with the average density of the molecular cloud.
dc.publisherCSLI Publications
dc.sourcePublications of the Astronomical Society of Australia
dc.subjectKeywords: Clouds: individual (G333.125-0.562, IRAS15596-5301); Cosmic rays; Radiation mechanisms:non-thermal
dc.titleSearch for synchrotron emission from secondary leptons in dense cold starless cores
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume25
dc.date.issued2008
local.identifier.absfor020104 - Galactic Astronomy
local.identifier.ariespublicationf5625xPUB10707
local.type.statusPublished Version
local.contributor.affiliationJones, D I, University of Adelaide
local.contributor.affiliationProtheroe, Raymond, University of Adelaide
local.contributor.affiliationCrocker, Roland, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.issue4
local.bibliographicCitation.startpage161
local.bibliographicCitation.lastpage166
local.identifier.doi10.1071/AS08007
dc.date.updated2016-02-24T08:36:49Z
local.identifier.scopusID2-s2.0-57049168040
CollectionsANU Research Publications

Download

File Description SizeFormat Image
01_Jones_Search_for_synchrotron_2008.pdf761 kBAdobe PDF    Request a copy


Items in Open Research are protected by copyright, with all rights reserved, unless otherwise indicated.

Updated:  17 November 2022/ Responsible Officer:  University Librarian/ Page Contact:  Library Systems & Web Coordinator