The MHz-peaked radio spectrum of the unusual γ-ray source PMN J1603–4904

dc.contributor.authorMüller, C.
dc.contributor.authorBurd, P. R.
dc.contributor.authorSchulz, R.
dc.contributor.authorCoppejans, R.
dc.contributor.authorFalcke, H.
dc.contributor.authorIntema, H.
dc.contributor.authorKadler, M.
dc.contributor.authorKrauß, F.
dc.contributor.authorOjha, R.
dc.date.accessioned2020-05-07T15:29:47Z
dc.date.available2020-05-07T15:29:47Z
dc.date.issued2016-09-27
dc.description.abstractContext. The majority of bright extragalactic γ-ray sources are blazars. Only a few radio galaxies have been detected by Fermi/LAT. Recently, the GHz-peaked spectrum source PKS 1718–649 was confirmed to be γ-ray bright, providing further evidence for the existence of a population of γ-ray loud, compact radio galaxies. A spectral turnover in the radio spectrum in the MHz to GHz range is a characteristic feature of these objects, which are thought to be young due to their small linear sizes. The multiwavelength properties of the γ-ray source PMN J1603–4904 suggest that it is a member of this source class. Aims. The known radio spectrum of PMN J1603–4904 can be described by a power law above 1 GHz. Using observations from the Giant Metrewave Radio Telescope (GMRT) at 150, 325, and 610 MHz, we investigate the behavior of the spectrum at lower frequencies to search for a low-frequency turnover. Methods. Data from the TIFR GMRT Sky Survey (TGSS ADR) catalog and archival GMRT observations were used to construct the first MHz to GHz spectrum of PMN J1603–4904. Results. We detect a low-frequency turnover of the spectrum and measure the peak position at about 490 MHz (rest-frame), which, using the known relation of peak frequency and linear size, translates into a maximum linear source size of ~1.4 kpc. Conclusions. The detection of the MHz peak indicates that PMN J1603–4904 is part of this population of radio galaxies with turnover frequencies in the MHz to GHz regime. Therefore it can be considered the second confirmed object of this kind detected in γ-rays. Establishing this γ-ray source class will help to investigate the γ-ray production sites and to test broadband emission models.en_US
dc.description.sponsorshipWe thank the anonymous referee for the prompt review and T. Beuchert for helpful comments that improved the manuscript. We thank the staff of the GMRT that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. This paper makes use of ALMA calibrator database: https://almascience.eso.org/alma-data/calibrator-catalogue. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ. C.M. and H.F. acknowledge support from the ERC Synergy Grant “BlackHoleCam – Imaging the Event Horizon of Black Holes” (Grant 610058). F.K. acknowledges funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 653477. R.S. acknowledges support from the ERC under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Advanced Grant RADIOLIFE-320745. This research was funded in part by NASA through Fermi Guest Investigator grant NNH13ZDA001N-FERMI.en_US
dc.description.urihttps://www.aanda.org/articles/aa/abs/2016/09/aa29547-16/aa29547-16.htmlen_US
dc.format.extent4 pagesen_US
dc.genrejournal articlesen_US
dc.identifierdoi:10.13016/m2ujdd-luji
dc.identifier.citationThe MHz-peaked radio spectrum of the unusual γ-ray source PMN J1603–4904 C. Müller, P. R. Burd, R. Schulz, R. Coppejans, H. Falcke, H. Intema, M. Kadler, F. Krauß and R. Ojha A&A, 593 (2016) L19 DOI: https://doi.org/10.1051/0004-6361/201629547en_US
dc.identifier.urihttps://doi.org/10.1051/0004-6361/201629547
dc.identifier.urihttp://hdl.handle.net/11603/18496
dc.identifier.urihttp://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2016A%26A...593L..19M
dc.identifier.urihttps://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Search&refcode=2016A%26A...593L..19M
dc.identifier.urihttp://telbib.eso.org/detail.php?bibcode=2016A%26A...593L..19M
dc.identifier.urihttps://ui.adsabs.harvard.edu/link_gateway/2016A%26A...593L..19M/ALMA
dc.language.isoen_USen_US
dc.publisherEDP sciencesen_US
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Physics Department Collection
dc.relation.ispartofUMBC Faculty Collection
dc.relation.ispartofUMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)
dc.rightsThis item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author.
dc.rights© ESO 2016
dc.titleThe MHz-peaked radio spectrum of the unusual γ-ray source PMN J1603–4904en_US
dc.typeTexten_US

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