The Fermi-LAT Lightcurve Repository*

Abdollahi, S.; Ajello, M.; Baldini, Luca; Ballet, J.; Bastieri, D.; González, J. Becerra; Bellazzini, R.; Berretta, A.; Bissaldi, E.; Bonino, R.; Brill, A.; Bruel, P.; Burns, E.; Buson, S.; Cameron, R. A.; Caputo, R.; Caraveo, P. A.; Cibrario, N.; Ciprini, S.; Orestano, P. Cristarella; Crnogorcevic, M.; Cutini, S.; D’Ammando, F.; Gaetano, S. De; Digel, S. W.; Lalla, N. Di; Venere, L. Di; Domínguez, A.; Ramazani, V. Fallah; Fegan, S. J.; Ferrara, E. C.; Fiori, A.; Fleischhack, Henrike; Franckowiak, A.; Fukazawa, Yasushi; Fusco, P.; Gammaldi, Viviana; Gargano, F.; Garrappa, S.; Gasbarra, C; Gasparrini, D.; Giglietto, N.; Giordano, F.; Giroletti, M.; Green, D.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hays, E.; Horan, D.; Hou, X.; Jóhannesson, G.; Kerr, M.; Kocevski, D.; Kuss, M.; Latronico, L.; Li, Jian; Liodakis, Ioannis; Longo, F.; Loparco, F.; Lorusso, L.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Maldera, S.; Manfreda, Alberto; Martí-Devesa, G.; Mazziotta, M. N.; Mereu, I.; Meyer, M.; Michelson, P. F.; Mizuno, T.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Negro, Michela; Omodei, N.; Orlando, Elena; Ormes, J. F.; Paneque, D.; Panzarini, G.; Perkins, J. S.; Peršić, M.; Pesce-Rollins, M.; Pillera, Roberta; Porter, T. A.; Principe, G.; Racusin, J. L.; Rainò, S.; Rando, R.; Rani, Bindu; Razzano, M.; Razzaque, S.; Reimer, A.; Reimer, O.; Sánchez‐Conde, Miguel A.; Parkinson, P. M. Saz; Scargle, J. D.; Scotton, L.; Serini, D.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Thompson, D. J.; Torres, D. F.; Valverde, J.; Venters, Tonia M.; Wadiasingh, Zorawar; Wagner, S.; Wood, K. S.

doi:10.3847/1538-4365/acbb6a

Cited by 38 publications

(19 citation statements)

References 21 publications

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“…All the multiwavelength observations are available upon request to the individual observatories. We supplement our campaign with 3 day binned publicly available Fermi Large Area Telescope data from the light curve repository 69 (Abdollahi et al 2023).…”

Section: Multiwavelength Observationsmentioning

confidence: 99%

IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

Middei

Perri

Puccetti

et al. 2023

ApJL

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The lower-energy peak of the spectral energy distribution of blazars has commonly been ascribed to synchrotron radiation from relativistic particles in the jets. Despite the consensus regarding jet emission processes, the particle acceleration mechanism is still debated. Here, we present the first X-ray polarization observations of PG 1553+113, a high-synchrotron-peak blazar observed by the Imaging X-ray Polarimetry Explorer (IXPE). We detect an X-ray polarization degree of (10 ± 2)% along an electric-vector position angle of ψ X = 86° ± 8°. At the same time, the radio and optical polarization degrees are lower by a factor of ∼3. During our IXPE pointing, we observed the first orphan optical polarization swing of the IXPE era, as the optical angle of PG 1553+113 underwent a smooth monotonic rotation by about 125°, with a rate of ∼17° day–1. We do not find evidence of a similar rotation in either radio or X-rays, which suggests that the X-ray and optically emitting regions are separate or, at most, partially cospatial. Our spectropolarimetric results provide further evidence that the steady-state X-ray emission in blazars originates in a shock-accelerated and energy-stratified electron population.

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Section: Multiwavelength Observationsmentioning

confidence: 99%

IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

Middei

Perri

Puccetti

et al. 2023

ApJL

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“…These findings suggest possibly a common γ-ray production mechanism and that FR0s also host misaligned jets similar to FR I and II radio galaxies. Additionally, we also explored the γ-ray variability behavior of FR0 objects using the Fermi-LAT light-curve repository (Abdollahi et al 2023). This repository contains the γ-ray light curves of all sources flagged as variable in the 4FGL Catalog.…”

Section: Discussionmentioning

confidence: 99%

Hunting Gamma-Ray-emitting FR0 Radio Galaxies in Wide-field Sky Surveys

Pannikkote,

Paliya,

Saikia

2023

ApJ

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The latest entry in the jetted active galactic nuclei (AGN) family is the Fanaroff–Riley type 0 (FR0) radio galaxies. They share several observational characteristics, e.g., nuclear emission and host galaxy morphology, with FR I sources; however, they lack extended, kiloparsec-scale radio structures, which are the defining features of canonical FR I and II sources. Here we report the identification of seven γ-ray-emitting AGN as FR0 radio sources by utilizing the high-quality observations delivered by ongoing multiwavelength wide-field sky surveys, e.g., Very Large Array Sky Survey. The broadband observational properties of these objects are found to be similar to their γ-ray undetected counterparts. In the γ-ray band, FR0 radio galaxies exhibit spectral features similar to more common FR I and II radio galaxies, indicating a common γ-ray production mechanism and the presence of misaligned jets. Although the parsec-scale radio structure of FR0s generally exhibits a wide range, with about half having emission on opposite sides of the core, the γ-ray-detected FR0s tend to have dominant cores with core-jet structures. We conclude that dedicated, high-resolution observations are needed to unravel the origin of relativistic jets in this enigmatic class of faint yet numerous population of compact radio sources.

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“…This final sample contains 28 BL Lac objects and one BCU listed in Table 1. All sources have been flagged as variable in the 4FGL-DR3 catalog (see also Abdollahi et al 2023).…”

Section: Sample Selectionmentioning

confidence: 99%

Very High-energy (>50 GeV) Gamma-Ray Flux Variability of Bright Fermi Blazars

Paliya

2024

ApJ

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Understanding the high-energy emission processes and variability patterns are two of the most challenging research problems associated with relativistic jets. In particular, the long-term (months to years) flux variability at very high energies (VHE >50 GeV) has remained an unexplored domain so far. This is possibly due to the decreased sensitivity of the Fermi Large Area Telescope (LAT) above a few GeV, hence low photon statistics, and observing constraints associated with the ground-based Cherenkov telescopes. This paper reports the results obtained from the 0.05−2 TeV Fermi-LAT data analysis of a sample of 29 blazars with the primary objective to explore their months-to-year-long very high-energy (VHE) flux variability behavior. This systematic search has led to, for the first time, the detection of significant flux variations in five blazars at the >99% confidence level, whereas eight of them exhibit variability, albeit at a lower confidence level (∼95%–99%). A comparison of the 0.05–2 TeV flux variations with that observed at 0.1–50 GeV band has revealed similar variability behavior for most of the sources. However, complex variability patterns that are not reflected contemporaneously in both energy bands were also detected, thereby providing tantalizing clues about the underlying radiative mechanisms. These results open up a new dimension to unravel the VHE emission processes operating in relativistic jets, hence sowing the seeds for their future observations with the upcoming Cherenkov Telescope Array.

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The Fermi-LAT Lightcurve Repository*

Cited by 38 publications

References 21 publications

IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

IXPE and Multiwavelength Observations of Blazar PG 1553+113 Reveal an Orphan Optical Polarization Swing

Hunting Gamma-Ray-emitting FR0 Radio Galaxies in Wide-field Sky Surveys

Very High-energy (>50 GeV) Gamma-Ray Flux Variability of Bright Fermi Blazars

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