The awakening of the gamma-ray narrow-Line Seyfert 1 galaxy PKS 1502+036

Abstract

After a long low-activity period, a gamma-ray flare from the narrow-line Seyfert 1 PKS 1502+036 (z=0.4089) was detected by the Large Area Telescope (LAT) on board Fermi in 2015. On 2015 December 20 the source reached a daily peak flux, in the 0.1-300 GeV band, of (93 $\pm$ 19) $\times$10${}^{-8}$ ph cm${}^{-2}$ s${}^{-1}$, attaining a flux of (237 $\pm$ 71) $\times$10${}^{-8}$ ph cm${}^{-2}$ s${}^{-1}$ on 3-hr time-scales, which corresponds to an isotropic luminosity of (7.3 $\pm$ 2.1) $\times$10${}^{47}$ erg/s. The gamma-ray flare was not accompanied by significant spectral changes. We report on multi-wavelength radio-to-gamma-ray observations of PKS 1502+036 during 2008 August-2016 March by Fermi-LAT, Swift, XMM-Newton, Catalina Real-Time Transient Survey, and the Owens Valley Radio Observatory (OVRO). An increase in activity was observed on 2015 December 22 by Swift in optical, UV, and X-rays. The OVRO 15 GHz light curve reached the highest flux density observed from this source on 2016 January 12, indicating a delay of about three weeks between the gamma-ray and 15 GHz emission peaks. This suggests that the gamma-ray emitting region is located beyond the broad line region. We compared the spectral energy distribution (SED) of an average activity state with that of the flaring state. The two SED, with the high-energy bump modelled as an external Compton component with seed photons from a dust torus, could be fitted by changing the electron distribution parameters as well as the magnetic field. The fit of the disc emission during the average state constrains the black hole mass to values lower than 10${}^8$ solar masses. The SED, high-energy emission mechanisms, and gamma-ray properties of the source resemble those of a flat spectrum radio quasar.

13 pages, 4 tables, 7 figures. Accepted for publication in the Monthly Notices of the Royal Astronomical Society. arXiv admin note: text overlap with arXiv:1305.0572

References in corpus (15)

• Radio-Loudness of Active Galactic Nuclei: Observational Facts and Theoretical Implications
• The power of relativistic jets is larger than the luminosity of their accretion disks
• Synchrotron Self-Compton Analysis of TeV X-ray Selected BL Lacertae Objects
• A Population of Radio-loud Narrow Line Seyfert 1 Galaxies with Blazar-like Properties?
• The effect of radiation pressure on virial black hole mass estimates and the case of Narrow Line Seyfert 1 galaxies
• Paper II: Calibration of the Swift ultraviolet/optical telescope
• Gamma-Ray Studies of Blazars: Synchro-Compton Analysis of Flat Spectrum Radio Quasars
• Detection of significant cm to sub-mm band radio and gamma-ray correlated variability in Fermi bright blazars
• The Host Galaxies of Narrow-Line Seyfert 1s: Nuclear Dust Morphology and Starburst Rings
• Radio/gamma-ray time delay in the parsec-scale cores of active galactic nuclei
• Radio jet emission from GeV-emitting narrow-line Seyfert 1 galaxies
• The first gamma-ray detection of the narrow-line Seyfert 1 FBQS J1644+2619
• The most powerful flaring activity from the NLSy1 PMN J0948+0022
• The Catalina Real-Time Transient Survey (CRTS)
• Unusual Flaring Activity in the Blazar PKS 1424-418 during 2008-2011

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• Broadband X-ray observations of four gamma-ray narrow-line Seyfert 1 galaxies
• Radio spectra of narrow-line Seyfert 1 galaxies observed with ATCA and VLASS
• Gamma-ray-emitting narrow-line Seyfert 1 galaxies: the Swift view
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• A γ-ray emitting NLS1 galaxy SDSS J095909.51+460014.3 identified by multiwavelength contemporaneous brightening
• Relativistic Jets in Gamma-Ray-Emitting Narrow-Line Seyfert 1 Galaxies