Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056
| dc.contributor.author | Ros, E. | |
| dc.contributor.author | Kadler, M. | |
| dc.contributor.author | Perucho, M. | |
| dc.contributor.author | Boccardi, B. | |
| dc.contributor.author | Cao, H.-M. | |
| dc.contributor.author | Giroletti, M. | |
| dc.contributor.author | Krauß, F. | |
| dc.contributor.author | Ojha, R. | |
| dc.date.accessioned | 2020-02-03T16:48:19Z | |
| dc.date.available | 2020-02-03T16:48:19Z | |
| dc.date.issued | 2019-12-23 | |
| dc.description.abstract | IceCube has reported a very-high-energy neutrino (IceCube-170922A) in a region containing the blazar TXS 0506+056. Correlated {\gamma}-ray activity has led to the first high-probability association of a high-energy neutrino with an extragalactic source. This blazar has been found to be in a radio outburst during the neutrino event. We have performed target-of-opportunity VLBI imaging observations at 43 GHz frequency with the VLBA two and eight months, respectively, after the neutrino event. We produced two images of TXS 0506+056 with angular resolutions of (0.2x1.1) mas and (0.2x0.5) mas, respectively. The source shows a compact, high brightness temperature core (albeit not approaching the equipartition limit) and a bright and originally very collimated inner jet. Beyond about 0.5 mas from the mm-VLBI core, the jet loses this tight collimation and expands rapidly. During the months after the neutrino event associated with this source, the overall flux density is rising. This flux density increase happens solely within the core. The core expands in size with apparent superluminal velocity during these six months so that the brightness temperature drops by a factor of three in spite of the strong flux density increase. The radio jet of TXS 0506+056 shows strong signs of deceleration and/or a spine-sheath structure within the inner 1 mas (corresponding to about 70 pc to 140 pc in deprojected distance) from the mm-VLBI core. This structure is consistent with theoretical models that attribute the neutrino and {\gamma}-ray production to interactions of electrons and protons in the highly-relativistic jet spine with external photons originating from a slower-moving jet region. Proton loading due to jet-star interactions in the inner host galaxy is suggested as the possible cause of deceleration | en_US |
| dc.description.sponsorship | We are especially thankful to N. MacDonald for valuable comments. We also acknowledge C. Breu for support during the data calibration. We thank the anonymous referee for the rapid and very constructive comments to the manuscript. The Very Long Baseline Array is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. F. K. was supported as an Eberly Research Fellow by the Eberly College of Science at the Pennsylvania State University. This research has made use of National Aeronautics and Space Administration’s (NASA) Astrophysics Data System, and of the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. | en_US |
| dc.description.uri | https://www.aanda.org/articles/aa/abs/2020/01/aa37206-19/aa37206-19.html | en_US |
| dc.description.uri | http://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2020A%26A...633L...1R | |
| dc.format.extent | 5 pages | en_US |
| dc.genre | journal articles | en_US |
| dc.identifier | doi:10.13016/m2xltt-ld0p | |
| dc.identifier.citation | Ros, E.; Kadler, M.; Perucho, M.; Boccardi, B.; Cao, H.-M.; Giroletti, M.; Krauß, F.; Ojha, R.; Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056; Astronomy & Astrophysics 633 (2019); https://www.aanda.org/articles/aa/abs/2020/01/aa37206-19/aa37206-19.html | en_US |
| dc.identifier.uri | http://hdl.handle.net/11603/17213 | |
| dc.language.iso | en_US | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Center for Space Sciences and Technology | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.rights | This 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 | Attribution 4.0 International (CC BY 4.0) | |
| dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | |
| dc.title | Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056 | en_US |
| dc.title.alternative | Letter to the Editor : Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056 | en_US |
| dc.type | Text | en_US |