The Origin of the X-Ray Emission in Two Well-aligned Extragalactic Jets: The Case for IC/CMB
| dc.contributor.author | Meyer, Eileen T. | |
| dc.contributor.author | Iyer, Adurshsiva R. | |
| dc.contributor.author | Reddy, Karthik | |
| dc.contributor.author | Georganopoulos, Markos | |
| dc.contributor.author | Breiding, Peter | |
| dc.contributor.author | Keenan, Mary | |
| dc.date.accessioned | 2019-11-22T18:02:30Z | |
| dc.date.available | 2019-11-22T18:02:30Z | |
| dc.date.issued | 2019-09-17 | |
| dc.description.abstract | Over the past two decades, the most commonly adopted explanation for high and hard X-ray emission in resolved quasar jets has been inverse-Compton upscattering of the cosmic microwave background (IC/CMB), which requires jets that remain highly relativistic on 10–1000 kpc scales. In more recent years various lines of observational evidence, including gamma-ray upper limits, have disfavored this explanation in favor of a synchrotron origin. While the IC/CMB model generally predicts a high level of gamma-ray emission, it has never been detected. Here we report the detection of a low-state Fermi/LAT gamma-ray spectrum associated with two jetted active galactic nuclei that is consistent with the predictions of the IC/CMB model for their X-ray emission. We have used archival multiwavelength observations to make precise predictions for the expected minimum flux in the GeV band, assuming that the X-ray emission from the kiloparsec-scale jet is entirely due to the IC/CMB process. In both sources—OJ 287 and PKS 1510−089—the minimum-detected gamma-ray flux level agrees with predictions. Both sources exhibit extreme superluminal proper motions relative to their jet power, which argues for the well-aligned jets required by the IC/CMB model. In the case of PKS 1510−089, it cannot be ruled out that the minimum gamma-ray flux level is due to a low state of the variable core that only matches the IC/CMB prediction by chance. Continued long-term monitoring with the Fermi/LAT could settle this issue by detecting a plateau signature in the recombined light curve that would clearly signal the presence of a nonvariable emission component. | en_US |
| dc.description.sponsorship | E.T.M. acknowledges NASA Fermi grants NNX15AU78G and 80NSSC18K1733. E.T.M. and M.G. acknowledge NASA ADP grant NNX15AE55G and NSF grant 1714380. This paper makes use of the following ALMA data: 1. ADS/JAO.ALMA#2016.1.00406.S 2. ADS/JAO.ALMA#2016.1.00116.S ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), MOST 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. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. Facilities: VLA, ALMA, HST, Chandra, Fermi. | en_US |
| dc.description.uri | https://iopscience.iop.org/article/10.3847/2041-8213/ab3db3 | en_US |
| dc.format.extent | 7 pages | en_US |
| dc.genre | journal articles | en_US |
| dc.identifier | doi:10.13016/m20teu-pnhr | |
| dc.identifier.citation | Meyer, Eileen T.; Iyer, Adurshsiva R.; Reddy, Karthik; Georganopoulos, Markos; Breiding, Peter; Keenan, Mary; The Origin of the X-Ray Emission in Two Well-aligned Extragalactic Jets: The Case for IC/CMB; The Astrophysical Journal Letters, Volume 883, Number 1 (2019); https://iopscience.iop.org/article/10.3847/2041-8213/ab3db3 | en_US |
| dc.identifier.uri | https://doi.org/10.3847/2041-8213/ab3db3 | |
| dc.identifier.uri | http://hdl.handle.net/11603/16514 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | The American Astronomical Society | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Physics Department Collection | |
| 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 | ©2019. The American Astronomical Society. All rights reserved. | |
| dc.subject | jets | en_US |
| dc.subject | radio loud quasars | en_US |
| dc.subject | BL lacertae objects | en_US |
| dc.subject | high energy astrophysics | en_US |
| dc.title | The Origin of the X-Ray Emission in Two Well-aligned Extragalactic Jets: The Case for IC/CMB | en_US |
| dc.type | Text | en_US |