New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. We report on the results of a search for radio transients between 115 and 190 MHz with the LOw-Frequency ARray (LOFAR). Four fields have been monitored with cadences between 15 min and several months...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Oxford University Press
2016
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| Online Access: | http://hdl.handle.net/20.500.11937/27632 |
| _version_ | 1848752317407428608 |
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| author | Carbone, D. Van Der Horst, A. Wijers, R. Swinbank, J. Rowlinson, A. Broderick, J. Cendes, Y. Stewart, A. Bell, M. Breton, R. Corbel, S. Eislöffel, J. Fender, R. Grießmeier, J. Hessels, J. Jonker, P. Kramer, M. Law, C. Miller-Jones, James Pietka, M. Scheers, L. Stappers, B. Van Leeuwen, J. Wijnands, R. Wise, M. Zarka, P. |
| author_facet | Carbone, D. Van Der Horst, A. Wijers, R. Swinbank, J. Rowlinson, A. Broderick, J. Cendes, Y. Stewart, A. Bell, M. Breton, R. Corbel, S. Eislöffel, J. Fender, R. Grießmeier, J. Hessels, J. Jonker, P. Kramer, M. Law, C. Miller-Jones, James Pietka, M. Scheers, L. Stappers, B. Van Leeuwen, J. Wijnands, R. Wise, M. Zarka, P. |
| author_sort | Carbone, D. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. We report on the results of a search for radio transients between 115 and 190 MHz with the LOw-Frequency ARray (LOFAR). Four fields have been monitored with cadences between 15 min and several months. A total of 151 images were obtained, giving a total survey area of 2275 deg2. We analysed our data using standard LOFAR tools and searched for radio transients using the LOFAR Transients Pipeline. No credible radio transient candidate has been detected; however, we are able to set upper limits on the surface density of radio transient sources at low radio frequencies. We also show that low-frequency radio surveys are more sensitive to steep-spectrum coherent transient sources than GHz radio surveys. We used two new statistical methods to determine the upper limits on the transient surface density. One is free of assumptions on the flux distribution of the sources, while the other assumes a power-law distribution in flux and sets more stringent constraints on the transient surface density. Both of these methods provide better constraints than the approach used in previous works. The best value for the upper limit we can set for the transient surface density, using the method assuming a power-law flux distribution, is 1.3 × 10-3 deg-2 for transients brighter than 0.3 Jy with a time-scale of 15 min, at a frequency of 150 MHz. We also calculated for the first time upper limits for the transient surface density for transients of different time-scales. We find that the results can differ by orders of magnitude from previously reported, simplified estimates. |
| first_indexed | 2025-11-14T08:06:42Z |
| format | Journal Article |
| id | curtin-20.500.11937-27632 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:06:42Z |
| publishDate | 2016 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-276322017-09-13T15:07:50Z New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR Carbone, D. Van Der Horst, A. Wijers, R. Swinbank, J. Rowlinson, A. Broderick, J. Cendes, Y. Stewart, A. Bell, M. Breton, R. Corbel, S. Eislöffel, J. Fender, R. Grießmeier, J. Hessels, J. Jonker, P. Kramer, M. Law, C. Miller-Jones, James Pietka, M. Scheers, L. Stappers, B. Van Leeuwen, J. Wijnands, R. Wise, M. Zarka, P. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. We report on the results of a search for radio transients between 115 and 190 MHz with the LOw-Frequency ARray (LOFAR). Four fields have been monitored with cadences between 15 min and several months. A total of 151 images were obtained, giving a total survey area of 2275 deg2. We analysed our data using standard LOFAR tools and searched for radio transients using the LOFAR Transients Pipeline. No credible radio transient candidate has been detected; however, we are able to set upper limits on the surface density of radio transient sources at low radio frequencies. We also show that low-frequency radio surveys are more sensitive to steep-spectrum coherent transient sources than GHz radio surveys. We used two new statistical methods to determine the upper limits on the transient surface density. One is free of assumptions on the flux distribution of the sources, while the other assumes a power-law distribution in flux and sets more stringent constraints on the transient surface density. Both of these methods provide better constraints than the approach used in previous works. The best value for the upper limit we can set for the transient surface density, using the method assuming a power-law flux distribution, is 1.3 × 10-3 deg-2 for transients brighter than 0.3 Jy with a time-scale of 15 min, at a frequency of 150 MHz. We also calculated for the first time upper limits for the transient surface density for transients of different time-scales. We find that the results can differ by orders of magnitude from previously reported, simplified estimates. 2016 Journal Article http://hdl.handle.net/20.500.11937/27632 10.1093/mnras/stw539 Oxford University Press fulltext |
| spellingShingle | Carbone, D. Van Der Horst, A. Wijers, R. Swinbank, J. Rowlinson, A. Broderick, J. Cendes, Y. Stewart, A. Bell, M. Breton, R. Corbel, S. Eislöffel, J. Fender, R. Grießmeier, J. Hessels, J. Jonker, P. Kramer, M. Law, C. Miller-Jones, James Pietka, M. Scheers, L. Stappers, B. Van Leeuwen, J. Wijnands, R. Wise, M. Zarka, P. New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title | New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title_full | New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title_fullStr | New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title_full_unstemmed | New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title_short | New methods to constrain the radio transient rate: Results from a survey of four fields with LOFAR |
| title_sort | new methods to constrain the radio transient rate: results from a survey of four fields with lofar |
| url | http://hdl.handle.net/20.500.11937/27632 |