scholarly journals Systematic Search for γ-Ray Periodicity in Active Galactic Nuclei Detected by the Fermi Large Area Telescope

2020 ◽  
Vol 896 (2) ◽  
pp. 134 ◽  
Author(s):  
P. Peñil ◽  
A. Domínguez ◽  
S. Buson ◽  
M. Ajello ◽  
J. Otero-Santos ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Systematic Search ◽  
Large Area ◽  
Γ Ray

scholarly journals A possible γ-ray quasi-periodic oscillation of ∼314 days in the blazar OJ 287

2020 ◽  
Vol 499 (1) ◽  
pp. 653-658
Author(s):  
Pankaj Kushwaha ◽  
Arkadipta Sarkar ◽  
Alok C Gupta ◽  
Ashutosh Tripathi ◽  
Paul J Wiita
Keyword(s):  
Light Curve ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Periodic Oscillation ◽  
Large Area ◽  
Quasi Periodic Oscillation ◽  
Bl Lacertae ◽  
Emission Models ◽  
Γ Ray ◽  
Blazar Oj 287

ABSTRACT We report the detection of a probable γ-ray quasi-periodic oscillation (QPO) of around 314 d in the monthly binned 0.1–300 GeV γ-ray Fermi-Large Area Telescope light curve of the well-known BL Lacertae blazar OJ 287. To identify and quantify the QPO nature of the γ-ray light curve of OJ 287, we used the Lomb–Scargle periodogram (LSP), REDFIT, and weighted wavelet Z-transform (WWZ) analyses. We briefly discuss possible emission models for radio-loud active galactic nuclei that can explain a γ-ray QPO of such a period in a blazar.

scholarly journals Gamma-ray observations of low-luminosity active galactic nuclei

2020 ◽  
Vol 492 (3) ◽  
pp. 4120-4130 ◽  
Author(s):  
Raniere de Menezes ◽  
Rodrigo Nemmen ◽  
Justin D Finke ◽  
Ivan Almeida ◽  
Bindu Rani
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Detailed Comparison ◽  
Spectral Energy ◽  
X Rays ◽  
Large Area ◽  
Accretion Flow ◽  
Γ Rays ◽  
Γ Ray

ABSTRACT The majority of the activity around nearby (z ≈ 0) supermassive black holes is found in low-luminosity active galactic nuclei (LLAGN), the most of them being classified as low-ionization nuclear emission regions. Although these sources are well studied from radio up to X-rays, they are poorly understood in γ-rays. In this work, we take advantage of the all sky-surveying capabilities of the Large Area Telescope on board Fermi Gamma-ray Space Telescope to study the whole Palomar sample of LLAGN in γ-rays. Precisely, the four radio-brightest LLAGN in the sample are identified as significant γ-ray emitters, all of which are recognized as powerful Fanaroff–Riley I galaxies. These results suggest that the presence of powerful radio jets is of substantial importance for observing a significant γ-ray counterpart even if these jets are misaligned with respect to the line of sight. We also find that most of the X-ray-brightest LLAGN do not have a significant γ-ray and strong radio emission, suggesting that the X-rays come mainly from the accretion flow in these cases. A detailed analysis of the spectral energy distributions (SEDs) of NGC 315 and NGC 4261, both detected in γ-rays, is provided where we make a detailed comparison between the predicted hadronic γ-ray emission from a radiatively inefficient accretion flow (RIAF) and the γ-ray emission from a leptonic jet-dominated synchrotron self-Compton (SSC) model. Both SEDs are better described by the SSC model, while the RIAF fails to explain the γ-ray observations.

scholarly journals DIFFUSE γ-RAY EMISSION FROM MISALIGNED ACTIVE GALACTIC NUCLEI

2013 ◽  
Vol 780 (2) ◽  
pp. 161 ◽  
Author(s):  
M. Di Mauro ◽  
F. Calore ◽  
F. Donato ◽  
M. Ajello ◽  
L. Latronico
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Γ Ray

scholarly journals Galaxy Evolution Studies with the SPace IR Telescope for Cosmology and Astrophysics (SPICA): The Power of IR Spectroscopy

2017 ◽  
Vol 34 ◽  
Author(s):  
L. Spinoglio ◽  
A. Alonso-Herrero ◽  
L. Armus ◽  
M. Baes ◽  
J. Bernard-Salas ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Formation Rate ◽  
Cosmic Time ◽  
Galactic Nuclei ◽  
Large Area ◽  
Radiation Fields ◽  
James Webb Space Telescope ◽  
Large Telescopes

AbstractIR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.

scholarly journals ERRATUM: “THE SECOND CATALOG OF ACTIVE GALACTIC NUCLEI DETECTED BY THE FERMI LARGE AREA TELESCOPE” (2011, ApJ, 743, 171)

2015 ◽  
Vol 806 (1) ◽  
pp. 144 ◽  
Author(s):  
M. Ackermann ◽  
M. Ajello ◽  
A. Allafort ◽  
E. Antolini ◽  
W. B. Atwood ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Large Area

scholarly journals Search for γ-ray emission from superluminous supernovae with the Fermi-LAT

2018 ◽  
Vol 611 ◽  
pp. A45 ◽  
Author(s):  
N. Renault-Tinacci ◽  
K. Kotera ◽  
A. Neronov ◽  
S. Ando
Keyword(s):  
Neutron Stars ◽  
Confidence Level ◽  
Compact Object ◽  
Photon Spectrum ◽  
Systematic Search ◽  
Large Area ◽  
Rotation Periods ◽  
Upper Limit ◽  
Upper Limits ◽  
Γ Ray

We present the first individual and stacking systematic search for γ-ray emission in the GeV band in the directions of 45 superluminous supernovae (SLSNe) with the Fermi Large Area Telescope (LAT). No excess of γ-rays from the SLSN positions was found. We report γ-ray luminosity upper limits and discuss the implication of these results on the origin of SLSNe and, in particular, the scenario of central compact object-aided SNe. From the stacking search, we derived an upper limit at 95% confidence level to the γ-ray luminosity (above 600 MeV) Lγ < 9.1 × 1041 erg s−1 for an assumed E−2 photon spectrum for our full SLSN sample. We conclude that the rate of the neutron stars born with millisecond rotation periods P ≲ 2 ms and B ~ 1012−13 G must be lower than the rate of the observed SLSNe. The luminosity limits obtained on individual sources are also constraining: in particular, SN2013fc, CSS140222, SN2010kd, and PTF12dam can only be born with millisecond periods if B ≲ 1013 G.

scholarly journals XMM–Newton observations of a sample of γ-ray loud active galactic nuclei

2006 ◽  
Vol 453 (3) ◽  
pp. 829-838 ◽  
Author(s):  
L. Foschini ◽  
G. Ghisellini ◽  
C. M. Raiteri ◽  
F. Tavecchio ◽  
M. Villata ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Γ Ray

scholarly journals Monitoring Of Jets in Active Galactic Nuclei with VLBA Experiments. XVIII. Kinematics and Inner Jet Evolution of Bright Radio-loud Active Galaxies

2021 ◽  
Vol 923 (1) ◽  
pp. 30
Author(s):  
M. L. Lister ◽  
D. C. Homan ◽  
K. I. Kellermann ◽  
Y. Y. Kovalev ◽  
A. B. Pushkarev ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Flow Instability ◽  
Galactic Nuclei ◽  
Position Angle ◽  
Spectral Energy ◽  
Large Area ◽  
Bl Lac Objects ◽  
Long Baseline ◽  
Bona Fide

Abstract We have analyzed the parsec-scale jet kinematics of 447 bright radio-loud active active galactic nuclei (AGN), based on 15 GHz Very Long Baseline Array (VLBA) data obtained between 1994 August 31 and 2019 August 4. We present new total intensity and linear polarization maps obtained between 2017 January 1 and 2019 August 4 for 143 of these AGN. We tracked 1923 bright features for five or more epochs in 419 jets. The majority (60%) of the well-sampled jet features show either accelerated or nonradial motion. In 47 jets there is at least one nonaccelerating feature with an unusually slow apparent speed. Most of the jets show variations of 10°–50° in their inner jet position angle (PA) over time, although the overall distribution has a continuous tail out to 200°. AGN with spectral energy distributions peaked at lower frequencies tend to have more variable PAs, with BL Lac objects being less variable than quasars. The Fermi Large Area Telescope (LAT) gamma-ray-associated AGN also tend to have more variable PAs than the non-LAT AGN in our sample. We attribute these trends to smaller viewing angles for the lower spectral peaked and LAT-associated jets. We identified 13 AGN where multiple features emerge over decade-long periods at systematically increasing or decreasing PAs. Since the ejected features do not fill the entire jet cross section, this behavior is indicative of a precessing flow instability near the jet base. Although some jets show indications of oscillatory PA evolution, we claim no bona fide cases of periodicity since the fitted periods are comparable to the total VLBA time coverage.

scholarly journals FERMI/LAT OBSERVATIONS OFSWIFT/BAT SEYFERT GALAXIES: ON THE CONTRIBUTION OF RADIO-QUIET ACTIVE GALACTIC NUCLEI TO THE EXTRAGALACTIC γ-RAY BACKGROUND

2011 ◽  
Vol 742 (2) ◽  
pp. 66 ◽  
Author(s):  
Stacy H. Teng ◽  
Richard F. Mushotzky ◽  
Rita M. Sambruna ◽  
David S. Davis ◽  
Christopher S. Reynolds
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Γ Ray

scholarly journals X/γ-rays from Active Galactic Nuclei

2000 ◽  
Vol 195 ◽  
pp. 143-152
Author(s):  
R. Svensson
Keyword(s):  
Active Galactic Nuclei ◽  
Large Fraction ◽  
Broad Band ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Spectral Components ◽  
Γ Rays ◽  
Γ Ray ◽  
Band Spectra ◽  
First Time

Recent progress using RXTE and BeppoSAX to study the X/γ emission from radio-quiet active galactic nuclei, i.e., Seyfert galaxies, is reviewed. These satellites allow simultaneous broad-band spectra extending from 0.1–200 keV to be observed for the first time and allow the various spectral components to be determined with some certainty. In particular, the new observations support the unified model of Seyfert galaxies. Most importantly, it has been found that a large fraction of Seyfert 2 galaxies have Compton-thick tori surrounding their nuclei. Spectral transitions in Seyfert galaxies are discussed, as well as recent efforts trying to synthesize the cosmic X/γ-ray background. Finally, thermal Comptonization in these sources are discussed.

Sign in / Sign up

Export Citation Format

Share Document