TXS 2116−077: A Gamma-Ray Emitting Relativistic Jet Hosted in a Galaxy Merger

Paliya, Vaidehi S.; Pérez, E.; García-Benito, R.; Ajello, M.; Prada, Francisco; Alberdi, A.; Suh, Hyewon; Chandra, C. H. Ishwara; Domínguez, A.; Marchesi, S.; Matteo, Tiziana Di; Hartmann, D. H.; Chiaberge, M.

doi:10.3847/1538-4357/ab754f

Cited by 16 publications

(22 citation statements)

References 69 publications

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“…Structures of interactions or recent mergers are often observed: PKS 1502 + 036 (z = 0.408, elliptical bulge plus nearby ring, recent merger, [59]), IRAS 20181 − 2244 (z = 0.185, ongoing interaction between two galaxies, the NLS1 seems to be hosted by a disk galaxy, [60]), TXS 2116 − 077 (z = 0.26, ongoing merger, disk galaxy with pseudobulge, [61,62], reclassified as intermediate Seyfert-type active nucleus [62]). In the case of SBS 0846 + 513 (z = 0.584), observations with the Large Binocular Telescope were not sufficient to distinguish between the two main options [63].…”

Section: Host Galaxymentioning

confidence: 99%

Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

Foschini

2020

Universe

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The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV photons emitted from more classes of AGN, like Seyferts, Compact Steep Spectrum Gigahertz Peaked Sources (CSS/GPS), and disk-hosted radio galaxies. Although observations indicate a variety of objects, their physical characteristics point to a central engine powered by a relatively small-mass black hole (but, obviously, there are interpretations against this view). This essay critically reviews the literature published on these topics during the last eight years and analyzes the perspectives for the forthcoming years.

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Section: Host Galaxymentioning

confidence: 99%

Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

Foschini

2020

Universe

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“…A systematic study by the latter authors indicates that the hosts of radio-loud NLSy 1s are preferentially disk galaxies, with a spiral galaxy suggested as the host for PKS 2004−447. Furthermore, high-resolution nearinfrared imaging of some of the NLSy 1s has also revealed ongoing galaxy mergers, thus suggesting a pivotal role played by such mergers in triggering the jet launching (see, e.g., Paliya et al 2020). Therefore, given the small sample of known γray NLSy 1 galaxies and their unclear nature, each new study of one of these objects can help improve our understanding of the underlying physical properties both in regard to their probable link to AGN evolution and to their role within the unified scheme of AGNs.…”

Section: Introductionmentioning

confidence: 99%

The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004–447

Gokus

Paliya

Wagner

et al. 2021

A&A

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Context. On 2019 October 25, the Fermi-Large Area Telescope observed the first ever γ-ray flare from the radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 (z = 0.24). Prior to this discovery, only four sources of this type had shown a flare at gigaelectronvolt energies. Aims. We report on follow-up observations in the radio, optical-UV, and X-ray bands that were performed by ATCA, the Neil Gehrels Swift Observatory, XMM-Newton, and NuSTAR, respectively, and analyse these multi-wavelength data with a one-zone leptonic model in order to understand the physical mechanisms that were responsible for the flare. Methods. We study the source’s variability across all energy bands and additionally produce γ-ray light curves with different time binnings to study the variability in γ-rays on short timescales during the flare. We examine the combined X-ray spectrum from 0.5 to 50 keV by describing the spectral shape with an absorbed power law. We analyse multi-wavelength datasets before, during, and after the flare and compare these with a low activity state of the source by modelling the respective spectral energy distributions (SEDs) with a one-zone synchrotron inverse Compton radiative model. Finally, we compare the variability and the SEDs to γ-ray flares previously observed from other γ-loud narrow-line Seyfert 1 galaxies. Results. At γ-ray energies (0.1−300 GeV) the flare reached a maximum flux of (1.3 ± 0.2) × 10−6 ph cm−2 s−1 in daily binning and a total maximum flux of (2.7 ± 0.6) × 10−6 ph cm−2 s−1 when a 3 h binning was used. With a photon index of Γ0.1−300 GeV = 2.42 ± 0.09 during the flare, this corresponds to an isotropic γ-ray luminosity of (2.9 ± 0.8) × 1047 erg s−1. The γ-ray, X-ray, and optical-UV light curves that cover the end of September to the middle of November show significant variability, and we find indications for flux-doubling times of ∼2.2 h at γ-ray energies. The soft X-ray excess, which is observed for most narrow-line Seyfert 1 galaxies, is not visible in this source. During the flare, the SED exhibits large Compton dominance. While the increase in the optical-UV range can be explained by enhanced synchrotron emission, the elevated γ-ray flux can be accounted for by an increase in the bulk Lorentz factor of the jet, similar to that observed for other flaring γ-ray blazars.

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“…A systematic study by the latter authors indicates that the hosts of radio-loud NLSy 1s are preferentially disk galaxies, with a spiral galaxy suggested as the host for PKS 2004−447. Furthermore, high-resolution near-infrared imaging of some of the NLSy1s has also revealed ongoing galaxy mergers, thus suggesting a pivotal role played by such mergers in triggering the jet launching (see, e.g., Paliya et al 2020). Therefore, given the small sample of known γ-ray NLSy 1 galaxies and their unclear nature, each new study of one of these objects can help improve our understanding of the underlying physical properties both in regard to their probable link to AGN evolution and to their role within the unified scheme of AGNs.…”

Section: Introductionmentioning

confidence: 99%

The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447

Gokus,

Paliya,

Wagner

et al. 2021

Preprint

Self Cite

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Context. On 2019 October 25, the Fermi-Large Area Telescope observed the first ever γ-ray flare from the radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 (z = 0.24). Prior to this discovery, only four sources of this type had shown a flare at Gigaelectronvolt energies. Aims. We report on follow-up observations in the radio, optical-UV, and X-ray bands that were performed by ATCA, the Neil Gehrels Swift observatory, XMM-Newton, and NuSTAR, respectively, and analyse these multi-wavelength data with a one-zone leptonic model in order to understand the physical mechanisms that were responsible for the flare. Methods. We study the source's variability across all energy bands and additionally produce γ-ray light curves with different time binnings to study the variability in γ-rays on short timescales during the flare. We examine the combined X-ray spectrum from 0.5-50 keV by describing the spectral shape with an absorbed power law. We analyse multi-wavelength datasets before, during, and after the flare and compare these with a low activity state of the source by modelling the respective spectral energy distributions (SEDs) with a one-zone synchrotron inverse Compton radiative model. Finally, we compare the variability and the SEDs to γ-ray flares previously observed from other γ-loud narrow-line Seyfert 1 galaxies. Results. At γ-ray energies (0.1-300 GeV) the flare reached a maximum flux of (1.3 ± 0.2) × 10 −6 ph cm −2 s −1 in daily binning and a total maximum flux of (2.7 ± 0.6) × 10 −6 ph cm −2 s −1 when a 3-hour binning was used. With a photon index of Γ 0.1−300GeV = 2.42 ± 0.09 during the flare, this corresponds to an isotropic γ-ray luminosity of (2.9 ± 0.8) × 10 47 erg s −1 . The γ-ray, X-ray, and optical-UV light curves that cover the end of September to the middle of November show significant variability, and we find indications for fluxdoubling times of ∼ 2.2 hours at γ-ray energies. The soft X-ray excess, which is observed for most narrow-line Seyfert 1 galaxies, is not visible in this source. During the flare, the SED exhibits large Compton dominance. While the increase in the optical-UV range can be explained by enhanced synchrotron emission, the elevated γ-ray flux can be accounted for by an increase in the bulk Lorentz factor of the jet, similar to that observed for other flaring γ-ray blazars.Conclusions.

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TXS 2116−077: A Gamma-Ray Emitting Relativistic Jet Hosted in a Galaxy Merger

Cited by 16 publications

References 69 publications

Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004–447

The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004-447

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