Pith. sign in

REVIEW 2 major objections 5 minor 162 references

Fermi-LAT finds VHE gamma rays from 14 Compton-dominated blazars and places their emission outside the broad-line region.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review · grok-4.5

2026-07-14 11:58 UTC pith:LQTFOA6O

load-bearing objection Solid catalog paper that cleanly expands the sparse VHE FSRQ sample with public LAT data and a uniform outside-BLR geometric constraint. the 2 major comments →

arxiv 2607.10407 v1 pith:LQTFOA6O submitted 2026-07-11 astro-ph.HE

Fermi-Large Area Telescope Detection of Very High Energy (>100 GeV) Emission from Compton-Dominated Blazars

P N Naseef Mohammed , Vaidehi S. Paliya , C D Ravikumar This is my paper
classification astro-ph.HE
keywords FSRQVHE gamma raysFermi-LATCompton dominancebroad-line regiongamma-gamma absorptionblazar jetsCherenkov Telescope Array
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

Broad-line blazars (FSRQs) are powered by luminous accretion disks whose broad-line region (BLR) photons both seed inverse-Compton gamma rays and absorb very-high-energy (VHE, >100 GeV) photons. This absorption has long explained why few FSRQs appear in TeV catalogs. Using ~17.5 years of Fermi-LAT data above 100 GeV, the authors search 626 Compton-dominated blazars and detect 14 sources at greater than or equal to 4 sigma, four of them for the first time at high significance. They also recover 21 additional objects that each produced at least one VHE photon. VHE photons arrive in both flaring and quiet states. Optical-depth calculations show that the emitting region must lie outside the BLR (beyond roughly 1.1-1.4 times the Lyman-alpha radius) so the observed photons can escape. The expanded sample supplies ready targets for the Cherenkov Telescope Array and multi-wavelength campaigns that can pin down the GeV-TeV radiative mechanism.

Core claim

A systematic Fermi-LAT search of 626 Compton-dominated blazars yields 14 VHE detections (TS greater than or equal to 16), including four new high-significance (TS greater than 25) sources, plus 21 more objects that each emit at least one VHE photon; optical-depth modelling of the BLR photon field requires the emission region to lie outside the BLR (greater than 1.1-1.4 R_Ly-alpha).

What carries the argument

Compton dominance greater than 1 as a proxy for radiatively efficient FSRQs, combined with unbinned Fermi-LAT likelihood analysis above 100 GeV and BLR gamma-gamma optical-depth profiles (Finke 2016 / agnpy) that convert observed VHE photon energies into lower limits on the emission-region distance.

Load-bearing premise

The entire sample and the emission-site limits rest on treating Compton dominance greater than 1 as a clean FSRQ proxy and fixing BLR luminosity at 10 percent of the disk luminosity under a spherical geometry; if either choice is systematically wrong the detections and the outside-BLR constraint both shift.

What would settle it

Deep Cherenkov Telescope Array or MAGIC/H.E.S.S./VERITAS observations of the four newly claimed high-significance sources that either fail to confirm VHE emission or recover a spectrum requiring the emission site to sit inside the BLR would falsify the central claims.

Watch this falsifier — get emailed when new claim-graph text bears on it.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. The paper presents a systematic unbinned-likelihood analysis of ~17.5 years of Fermi-LAT data (100 GeV–1 TeV) for 626 Compton-dominated (CD > 1) blazars drawn from Paliya et al. (2021). Using SOURCEVETO events, FL16Y background models, and gtsrcprob association probabilities ≥95 %, the authors report 14 sources with TS > 16 (≳4σ), of which ten reach TS > 25 (≳5σ); four of the high-significance detections are new. An additional 21 objects show at least one associated VHE photon. Monthly 0.1–100 GeV light curves demonstrate that VHE photons arrive during both flaring and quiescent states. Optical-depth calculations with the Finke (2016)/agnpy BLR model (spherical geometry, L_BLR = 0.1 L_disk) place the emission region outside the BLR (r ≳ 1.1–1.4 R_Lyα) for the observed photon energies. The work expands the known VHE FSRQ sample and supplies concrete targets for CTAO.

Significance. If the detections and geometric constraints hold, the paper substantially enlarges the sparse population of VHE-emitting broad-line blazars and supplies a clean observational lower bound on the location of the γ-ray zone. The analysis pipeline is standard and fully reproducible from public data; the outside-BLR conclusion is robust against order-unity changes in the conventional 10 % BLR luminosity fraction. The catalog of new candidates and the demonstration that VHE emission occurs in both high and low states are of immediate practical value for CTAO scheduling and multi-wavelength campaigns.

major comments (2)
  1. Section 4.1 and Table 1: four sources are claimed as first high-significance (TS > 25) VHE detections. For the two objects previously observed but undetected by MAGIC (e.g., 4C +55.17), a short quantitative comparison of the Fermi-LAT VHE flux (or upper limit) with the published MAGIC exposure and sensitivity would strengthen the novelty claim and rule out simple exposure differences.
  2. Section 4.3 and Figure 2: the emission-region lower limits rest on a fixed L_BLR = 0.1 L_disk and spherical geometry. While the qualitative “outside BLR” conclusion is robust, a brief sensitivity test (e.g., L_BLR/L_disk = 0.05–0.2 or a thin-shell geometry) should be shown or stated so that readers can judge how far the numerical factors 1.1–1.4 can shift.
minor comments (5)
  1. Table 1 header and caption: the units of photon flux are given as 10^{-12} ph cm^{-2} s^{-1}; confirm that the tabulated numbers are consistent with this scaling for every entry (some appear large for the faintest sources).
  2. Figure 1: the vertical dashed lines marking VHE photon arrivals are useful, but a short note in the caption indicating how many of the 47 photons fall inside versus outside flaring windows would make the 51 % / 49 % statement immediately verifiable.
  3. Section 4.4: the single 177 GeV photon from 4FGL J2326.2+0113 (z = 1.6, τ_EBL ≈ 4) is correctly flagged as tentative; the text already notes the back-conversion and lack of additional photons—consider moving this caution into the abstract or summary so that the cosmic-horizon discussion is not over-interpreted.
  4. Typographical consistency: “4FGL J538.8-4405” appears in Table 2 (missing leading zero); several photon-index uncertainties are quoted to one decimal place while fluxes use two—standardize.
  5. References: the FL16Y catalog is cited as Ballet et al. (2026); ensure the final arXiv or journal identifier is updated before publication.

Circularity Check

0 steps flagged

No significant circularity: VHE detections and outside-BLR limits are data-driven likelihood results plus a conventional external opacity model, not self-defined or fitted-to-target predictions.

full rationale

The central results (14 sources with TS>16, four new TS>25 detections, 21 single-photon candidates, and r ≳ 1.1–1.4 R_Lyα) follow from unbinned likelihood analysis of public Fermi-LAT data (Section 3) and the standard Finke (2016)/agnpy BLR opacity calculation with a conventional 10 % L_disk scaling taken from the literature (Section 4.3). Sample selection (CD > 1 from Paliya et al. 2021) is an independent prior catalog used only to define the parent list; it is not fitted to the VHE photon counts or TS values. No equation equates a claimed detection or location limit to a parameter that was itself adjusted to those same detections. Self-citations (Paliya et al. 2021, 2025) supply the parent sample and one previously reported source but are not load-bearing uniqueness theorems or ansatzes that force the present conclusions. The derivation is therefore self-contained against external data and models; the residual score of 1 reflects only the ordinary use of an author-overlapping catalog for sample definition, which does not reduce the VHE results by construction.

Axiom & Free-Parameter Ledger

2 free parameters · 4 axioms · 0 invented entities

The work rests on standard high-energy astrophysics tools and one conventional scaling for BLR luminosity. No new particles or forces are invented; free parameters are limited to the conventional 10 % BLR-to-disk luminosity ratio and the spherical geometry choice used for optical-depth curves.

free parameters (2)
  • BLR luminosity fraction = 0.1
    Fixed at 10 % of accretion-disk luminosity following Paliya et al. (2021); directly scales the γγ optical depth and therefore the derived lower limit on emission-region distance.
  • BLR geometry (spherical shell)
    Assumed spherical Lyman-α photon field in the Finke (2016)/agnpy calculation; alternative geometries would change the radial optical-depth profile.
axioms (4)
  • domain assumption Compton dominance >1 is a reliable proxy for radiatively efficient accretion and a luminous BLR (sample definition).
    Section 2; taken from Paliya et al. (2021) correlation; if the proxy fails, the parent sample is impure.
  • domain assumption Standard Fermi-LAT unbinned likelihood, SOURCEVETO class, and gtsrcprob association probability correctly identify source photons above 100 GeV.
    Section 3; conventional analysis choices whose validity is established by the Fermi collaboration.
  • domain assumption EBL attenuation model of Domínguez et al. (2011) and Saldana-Lopez et al. (2021) correctly describe pair-production opacity.
    Used for spectral correction and cosmic γ-ray horizon plot (Sections 3–4).
  • domain assumption γ-ray emission region can be treated as a point source relative to the BLR for optical-depth calculation.
    Implicit in the Finke (2016) formalism applied in Section 4.3.

pith-pipeline@v1.1.0-grok45 · 39798 in / 2699 out tokens · 35689 ms · 2026-07-14T11:58:20.966429+00:00 · methodology

0 comments
read the original abstract

The observation of broad emission lines in the optical spectra of flat-spectrum radio quasars (FSRQs) suggests radiatively efficient accretion powering these objects. In such broad emission line blazars, the intense broad-line region (BLR) radiation can provide seed photons for inverse Compton scattering, leading to a Compton-dominated spectral energy distribution. Interestingly, the same BLR photon field can also absorb very high-energy (VHE; E>100 GeV) $\gamma$-ray radiation, thus explaining the paucity of VHE-detected FSRQs. Here we report the results of a systematic search to identify VHE-emitting sources in a sample of 626 Compton-dominated blazars (Compton dominance > 1), using $\sim$17.5 years of Fermi-Large Area Telescope observations. We identified 14 blazars at greater than 4$\sigma$ confidence level, including 4 sources detected in the VHE band at high significance (> 5$\sigma$) for the first time. We also found 21 objects from which at least one VHE photon was detected, thus substantially expanding the known VHE FSRQ population. Investigating the temporal coincidence of the VHE photons with the $\gamma$-ray activity, we noticed the VHE emission to be detected during flaring as well as low jet activity epochs. By estimating the optical depth for the $\gamma$$\gamma$ absorption due to the BLR photon field, we constrained the VHE-emitting region to be located outside BLR (>1.1-1.4$\times$ BLR radius). We conclude that multi-wavelength followup observations of these enigmatic VHE-detected broad line blazars will permit us to constrain the radiative processes responsible for the GeV-TeV emission, and will set the benchmark for their observations with the upcoming Cherenkov Telescope Array Observatory.

Figures

Figures reproduced from arXiv: 2607.10407 by C D Ravikumar, P N Naseef Mohammed, Vaidehi S. Paliya.

Figure 1
Figure 1. Figure 1: Monthly-binned light curves of VHE sources (TS>25) in the energy range 0.1−100 GeV constructed using the data taken from Fermi-LAT Light Curve Repository. In each plot, top panel represents the photon flux in units of 10−7 ph 𝑐𝑚−2 𝑠 −1 , and bottom panel refers to the photon index. The red dashed vertical lines represent the time of arrival of VHE photons. 4FGL J1031.1+7442. Particularly, out of 47 VHE pho… view at source ↗
Figure 2
Figure 2. Figure 2: Optical depth due to 𝛾𝛾 pair production with the BLR photons as a function of 𝛾-ray photon energy for different distances of the emission region from the photon field. Energies of detected VHE photons are highlighted by the vertical dotted lines. See the text for details. luminosity, following Paliya et al. (2021). We derived 𝜏𝛾𝛾 as a function of photon energy for different distances of the emission region… view at source ↗
Figure 3
Figure 3. Figure 3: Cosmic 𝛾-ray horizon. The black solid line indicates the opacity regime corresponding to an EBL optical depth of 𝜏𝐸𝐵𝐿 = 1 (Saldana-Lopez et al., 2021). Source markers are color coded by their respective EBL optical depth values derived from the same model. The VHE-emitting FSRQs are shown as stars, whereas, filled circles refer to blazars present in the fourth catalog of the Fermi-LAT detected AGN (4LAC; A… view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

162 extracted references · 74 canonical work pages · 61 internal anchors

  1. [1]

    , year = 1970, month = apr, volume =

    Predicted High Energy Break in the Isotropic Gamma Ray Spectrum: a Test of Cosmological Origin. , year = 1970, month = apr, volume =. doi:10.1038/226135a0 , adsurl =

    doi:10.1038/226135a0 1970

  2. [2]

    , keywords =

    On the origin of gamma-rays in Fermi blazars: beyondthe broad-line region. , keywords =. doi:10.1093/mnras/sty887 , archivePrefix =. 1804.02408 , primaryClass =

    Pith/arXiv arXiv doi:10.1093/mnras/sty887

  3. [3]

    , keywords =

    The Extragalactic Background Light, the Hubble Constant, and Anomalies: Conclusions from 20 Years of TeV Gamma-ray Observations. , keywords =. doi:10.1088/0004-637X/812/1/60 , archivePrefix =. 1502.04166 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/0004-637x/812/1/60

  4. [4]

    Astroparticle Physics , keywords =

    The extragalactic background light and the gamma-ray opacity of the universe. Astroparticle Physics , keywords =. doi:10.1016/j.astropartphys.2012.09.003 , archivePrefix =. 1209.4661 , primaryClass =

    Pith/arXiv arXiv doi:10.1016/j.astropartphys.2012.09.003 2012

  5. [5]

    Astroparticle Physics , keywords =

    The first VERITAS telescope. Astroparticle Physics , keywords =. doi:10.1016/j.astropartphys.2006.04.002 , archivePrefix =. astro-ph/0604119 , primaryClass =

    Pith/arXiv arXiv doi:10.1016/j.astropartphys.2006.04.002 2006

  6. [6]

    Astroparticle Physics , keywords =

    The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula. Astroparticle Physics , keywords =. doi:10.1016/j.astropartphys.2015.02.005 , archivePrefix =. 1409.5594 , primaryClass =

    Pith/arXiv arXiv doi:10.1016/j.astropartphys.2015.02.005 2015

  7. [7]

    The Status of the H.E.S.S. Project

    The status of the HESS project. , keywords =. doi:10.1016/j.newar.2003.12.004 , archivePrefix =. astro-ph/0403052 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1016/j.newar.2003.12.004 2003

  8. [8]

    , keywords =

    The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large Area Telescope. , keywords =. doi:10.3847/1538-4357/ab791e , archivePrefix =. 1905.10771 , primaryClass =

    Pith/arXiv arXiv doi:10.3847/1538-4357/ab791e 1905

  9. [9]

    Spectral analysis of Fermi-LAT blazars above 50 GeV

    Spectral Analysis of Fermi-LAT Blazars above 50 GeV. , keywords =. doi:10.1088/2041-8205/813/2/L34 , archivePrefix =. 1510.07913 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/2041-8205/813/2/l34 2041

  10. [10]

    The Astronomer's Telegram , keywords =

    Strong very-high-energy gamma-ray flaring activity from FSRQ OP313 detected with the MAGIC telescopes. The Astronomer's Telegram , keywords =

  11. [11]

    The Astronomer's Telegram , keywords =

    First detection of VHE gamma-ray emission from FSRQ OP 313 with LST-1. The Astronomer's Telegram , keywords =

  12. [12]

    Search for Very-High-Energy Gamma Rays from the z = 0.896 Quasar 4C +55.17 with the MAGIC telescopes

    Search for very high energy gamma-rays from the z = 0.896 quasar 4C +55.17 with the MAGIC telescopes. , keywords =. doi:10.1093/mnras/stu227 , archivePrefix =. 1402.0291 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stu227

  13. [13]

    Hidden by a star: the redshift and the offset broad line of the Flat Spectrum Radio Quasar PKS 0903-57

    Hidden by a star: The redshift and the offset broad line of the flat-spectrum radio quasar PKS 0903─57. , keywords =. doi:10.1051/0004-6361/202451609 , archivePrefix =. 2410.06744 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/202451609

  14. [14]

    The Astronomer's Telegram , keywords =

    Detection of Very-High-Energy Gamma-rays from PKS 0903-57 by H.E.S.S. The Astronomer's Telegram , keywords =

  15. [15]

    ESO Very Large Telescope Optical Spectroscopy of BL Lacertae Objects. I. New Redshifts. , keywords =. doi:10.1086/427138 , archivePrefix =. astro-ph/0410692 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/427138

  16. [16]

    , keywords =

    The transition between BL Lac objects and flat spectrum radio quasars. , keywords =. doi:10.1111/j.1365-2966.2011.18578.x , archivePrefix =. 1012.0308 , primaryClass =

    doi:10.1111/j.1365-2966.2011.18578.x 2011

  17. [17]

    detection and multi-wavelength study of the z 1 blazar PKS 0346 - 27

    H.E.S.S. detection and multi-wavelength study of the z 1 blazar PKS 0346 - 27. , keywords =. doi:10.1051/0004-6361/202557228 , archivePrefix =. 2512.24228 , primaryClass =

    work page doi:10.1051/0004-6361/202557228

  18. [18]

    Broad-band continuum and line emission of the gamma-ray blazar PKS 0537-441

    Broad-band continuum and line emission of the gamma-ray blazar PKS 0537-441. , keywords =. doi:10.1051/0004-6361:20020881 , archivePrefix =. astro-ph/0207355 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20020881

  19. [19]

    , keywords =

    Spectroscopy of Broad-line Blazars from 1LAC. , keywords =. doi:10.1088/0004-637X/748/1/49 , archivePrefix =. 1201.0999 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/0004-637x/748/1/49

  20. [20]

    agnpy: An open-source python package modelling the radiative processes of jetted active galactic nuclei

    agnpy: An open-source python package modelling the radiative processes of jetted active galactic nuclei. , keywords =. doi:10.1051/0004-6361/202142000 , archivePrefix =. 2112.14573 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/202142000

  21. [21]

    , keywords =

    GeV Breaks in Blazars as a Result of Gamma-ray Absorption Within the Broad-line Region. , keywords =. doi:10.1088/2041-8205/717/2/L118 , archivePrefix =. 1005.3792 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/2041-8205/717/2/l118 2041

  22. [22]

    The Fermi-LAT Light Curve Repository

    The Fermi-LAT Lightcurve Repository. , keywords =. doi:10.3847/1538-4365/acbb6a , archivePrefix =. 2301.01607 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4365/acbb6a

  23. [23]

    , keywords =

    Detection of persistent VHE gamma-ray emission from PKS 1510-089 by the MAGIC telescopes during low states between 2012 and 2017. , keywords =. doi:10.1051/0004-6361/201833618 , archivePrefix =. 1806.05367 , primaryClass =

    Pith/arXiv arXiv doi:10.1051/0004-6361/201833618 2012

  24. [24]

    , keywords =

    VHE gamma-ray detection of FSRQ QSO B1420+326 and modeling of its enhanced broadband state in 2020. , keywords =. doi:10.1051/0004-6361/202039687 , archivePrefix =. 2012.11380 , primaryClass =

    doi:10.1051/0004-6361/202039687 2020

  25. [25]

    , keywords =

    Gamma-Rays from the Quasar PKS 1441+25: Story of an Escape. , keywords =. doi:10.1088/2041-8205/815/2/L22 , archivePrefix =. 1512.04434 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/2041-8205/815/2/l22 2041

  26. [26]

    , keywords =

    Very High Energy -Rays from the Universe's Middle Age: Detection of the z = 0.940 Blazar PKS 1441+25 with MAGIC. , keywords =. doi:10.1088/2041-8205/815/2/L23 , archivePrefix =. 1512.04435 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/2041-8205/815/2/l23 2041

  27. [27]

    Fermi Large Area Telescope Detection of Two Very-High-Energy (E>100 GeV) Gamma-ray Photons from the z = 1.1 Blazar PKS 0426-380

    Fermi Large Area Telescope Detection of Two Very-high-energy (E > 100 GeV) -Ray Photons from the z = 1.1 Blazar PKS 0426-380. , keywords =. doi:10.1088/2041-8205/777/1/L18 , archivePrefix =. 1308.0595 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/2041-8205/777/1/l18 2041

  28. [28]

    , keywords =

    The Likelihood Analysis of EGRET Data. , keywords =. doi:10.1086/177068 , adsurl =

    doi:10.1086/177068

  29. [29]

    arXiv e-prints , keywords =

    Fermi-LAT 16-year Source List. arXiv e-prints , keywords =. doi:10.48550/arXiv.2602.22148 , archivePrefix =. 2602.22148 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2602.22148

  30. [30]

    Radio Morphology of Gamma-ray Sources: Double-Lobed Radio Sources

    Radio Morphology of Gamma-Ray Sources: Double-lobed Radio Sources. , keywords =. doi:10.3847/1538-4357/ad85e2 , archivePrefix =. 2410.10192 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ad85e2

  31. [31]

    arXiv e-prints , keywords =

    Catalog of very-high-energy emitting active galactic nuclei at high Galactic latitudes. arXiv e-prints , keywords =. doi:10.48550/arXiv.2506.08497 , archivePrefix =. 2506.08497 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2506.08497

  32. [32]

    Journal of High Energy Astrophysics , keywords =

    Fermi-large area telescope detection of very high energy (>100 GeV) emission from misaligned jetted active galactic nuclei. Journal of High Energy Astrophysics , keywords =. doi:10.1016/j.jheap.2025.100454 , archivePrefix =. 2508.15921 , primaryClass =

    work page doi:10.1016/j.jheap.2025.100454 2025

  33. [33]

    , keywords =

    An observational determination of the evolving extragalactic background light from the multiwavelength HST/CANDELS survey in the Fermi and CTA era. , keywords =. doi:10.1093/mnras/stab2393 , archivePrefix =. 2012.03035 , primaryClass =

    Pith/arXiv arXiv doi:10.1093/mnras/stab2393 2012

  34. [34]

    H.E.S.S. detection of very-high-energy gamma-ray emission from the quasar PKS 0736+017

    H.E.S.S. detection of very high-energy -ray emission from the quasar PKS 0736+017. , keywords =. doi:10.1051/0004-6361/201935906 , archivePrefix =. 1911.04761 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201935906 1911

  35. [35]

    , keywords =

    Detection of very high energy gamma-ray emission from the gravitationally lensed blazar QSO B0218+357 with the MAGIC telescopes. , keywords =. doi:10.1051/0004-6361/201629461 , archivePrefix =. 1609.01095 , primaryClass =

    work page doi:10.1051/0004-6361/201629461

  36. [36]

    Astroparticle Physics , keywords =

    Radiation fields of disk, BLR and torus in quasars and blazars: implications for / -ray absorption. Astroparticle Physics , keywords =. doi:10.1016/S0927-6505(02)00155-X , archivePrefix =. astro-ph/0202068 , primaryClass =

    Pith/arXiv arXiv doi:10.1016/s0927-6505(02)00155-x

  37. [37]

    , keywords =

    Gamma-Gamma Absorption in the Broad Line Region Radiation Fields of Gamma-Ray Blazars. , keywords =. doi:10.3847/0004-637X/821/2/102 , archivePrefix =. 1603.02785 , primaryClass =

    Pith/arXiv arXiv doi:10.3847/0004-637x/821/2/102

  38. [38]

    , keywords =

    The NuSTAR view on hard-TeV BL Lacs. , keywords =. doi:10.1093/mnras/sty857 , archivePrefix =. 1711.06282 , primaryClass =

    Pith/arXiv arXiv doi:10.1093/mnras/sty857

  39. [39]

    , keywords =

    Hunting Very High-energy-emitting (>100 GeV) High-synchrotron-peaked Blazars. , keywords =. doi:10.3847/1538-4365/ae27be , adsurl =

    doi:10.3847/1538-4365/ae27be

  40. [40]

    , keywords =

    Unified Schemes for Radio-Loud Active Galactic Nuclei. , keywords =. doi:10.1086/133630 , archivePrefix =. astro-ph/9506063 , primaryClass =

    Pith/arXiv arXiv doi:10.1086/133630

  41. [41]

    , keywords =

    Relativistic Jets from Active Galactic Nuclei. , keywords =. doi:10.1146/annurev-astro-081817-051948 , archivePrefix =. 1812.06025 , primaryClass =

    Pith/arXiv arXiv doi:10.1146/annurev-astro-081817-051948

  42. [42]

    Hadronic blazar models and correlated X-ray/TeV flares

    Hadronic blazar models and correlated X-ray/TeV flares. GeV-TeV Gamma Ray Astrophysics Workshop : towards a major atmospheric , year = 2000, editor =. doi:10.1063/1.1291342 , archivePrefix =. astro-ph/0003282 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1063/1.1291342 2000

  43. [43]

    , keywords =

    The Spectral Energy Distribution of Fermi Bright Blazars. , keywords =. doi:10.1088/0004-637X/716/1/30 , archivePrefix =. 0912.2040 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/0004-637x/716/1/30 2040

  44. [44]

    , keywords =

    Gamma-Ray Studies of Blazars: Synchro-Compton Analysis of Flat Spectrum Radio Quasars. , keywords =. doi:10.1088/0004-637X/692/1/32 , archivePrefix =. 0808.3185 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/0004-637x/692/1/32

  45. [45]

    , keywords =

    The Detection of Teraelectronvolt Radiation from a Flat-spectrum Radio Quasar. , keywords =. doi:10.3847/2041-8213/ae018d , archivePrefix =. 2508.17659 , primaryClass =

    Pith/arXiv arXiv doi:10.3847/2041-8213/ae018d 2041

  46. [46]

    The Astrophysical Journal Supplement Series , keywords =

    Fermi Large Area Telescope Fourth Source Catalog. The Astrophysical Journal Supplement Series , keywords =

  47. [47]

    arXiv e-prints , keywords =

    Fermi Large Area Telescope Fourth Source Catalog Data Release 4 (4FGL-DR4). arXiv e-prints , keywords =. doi:10.48550/arXiv.2307.12546 , archivePrefix =. 2307.12546 , primaryClass =

    Pith/arXiv arXiv doi:10.48550/arxiv.2307.12546

  48. [48]

    Radio Galaxies at VHE energies

    Radio Galaxies at VHE Energies. Galaxies , keywords =. doi:10.3390/galaxies6040116 , archivePrefix =. 1810.05409 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3390/galaxies6040116

  49. [49]

    Gamma-ray flaring activity of NGC 1275 in 2016-2017 measured by MAGIC

    Gamma-ray flaring activity of NGC1275 in 2016-2017 measured by MAGIC. , keywords =. doi:10.1051/0004-6361/201832895 , archivePrefix =. 1806.01559 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201832895 2016

  50. [50]

    , keywords =

    Study of the Very High Energy Emission of M87 through its Broadband Spectral Energy Distribution. , keywords =. doi:10.3847/1538-4357/ac7b78 , archivePrefix =. 2112.09179 , primaryClass =

    Pith/arXiv arXiv doi:10.3847/1538-4357/ac7b78

  51. [51]

    Interpretation of the flares of M87 at TeV energies in the cloud-jet interaction scenario

    Interpretation of the Flares of M87 at TeV Energies in the Cloud-Jet Interaction Scenario. , keywords =. doi:10.1088/0004-637X/755/2/170 , archivePrefix =. 1202.5907 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/755/2/170

  52. [52]

    High-resolution VLA low radio frequency observations of the Perseus cluster: radio lobes, mini-halo and bent-jet radio galaxies

    High-resolution VLA low radio frequency observations of the Perseus cluster: radio lobes, mini-halo, and bent-jet radio galaxies. , keywords =. doi:10.1093/mnras/staa2003 , archivePrefix =. 2005.12298 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/staa2003 2005

  53. [53]

    Multiwavelength investigations of PKS 2300-18: S-shaped radio quasar with precessing jets and double-peaked broad emission-line spectrum

    Multiwavelength investigations of PKS 2300-18: S-shaped radio quasar with precessing jets and double-peaked broad emission-line spectrum. , keywords =. doi:10.1093/mnras/stae2639 , archivePrefix =. 2502.09441 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stae2639

  54. [54]

    Hunting extreme BL Lacertae blazars with Fermi-LAT

    Hunting extreme BL Lacertae blazars with Fermi-Large Area Telescope. , keywords =. doi:10.1093/mnras/stac491 , archivePrefix =. 2202.08785 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/stac491

  55. [55]

    35th International Cosmic Ray Conference (ICRC2017) , year = 2017, series =

    Fermipy: An open-source Python package for analysis of Fermi-LAT Data. 35th International Cosmic Ray Conference (ICRC2017) , year = 2017, series =. doi:10.22323/1.301.0824 , archivePrefix =. 1707.09551 , primaryClass =

    Pith/arXiv arXiv doi:10.22323/1.301.0824 2017

  56. [56]

    Radio Morphology of Gamma-ray Sources -- II. Giant Radio Galaxies

    Radio Morphology of Gamma-ray Sources -- II. Giant Radio Galaxies. arXiv e-prints , keywords =. doi:10.48550/arXiv.2507.03105 , archivePrefix =. 2507.03105 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2507.03105

  57. [57]

    , keywords =

    Morphological Transition of the Compact Radio Lobe in 3C 84 via the Strong Jet-Cloud Collision. , keywords =. doi:10.3847/2041-8213/ac24fa , adsurl =

    doi:10.3847/2041-8213/ac24fa 2041

  58. [58]

    Evidence of jet-clump interaction: a flip of the radio jet head of 3C~84

    Evidence of Jet-Clump Interaction: A Flip of the Radio Jet Head of 3C 84. , keywords =. doi:10.3847/1538-4357/aad6e3 , archivePrefix =. 1808.08855 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/aad6e3

  59. [59]

    Galaxies , keywords =

    Radio Galaxies at TeV Energies. Galaxies , keywords =. doi:10.3390/galaxies10030061 , adsurl =

    doi:10.3390/galaxies10030061

  60. [60]

    , keywords =

    LOFAR-Bo \"o tes: properties of high- and low-excitation radio galaxies at 0.5 < z < 2.0. , keywords =. doi:10.1093/mnras/sty026 , archivePrefix =. 1711.10504 , primaryClass =

    Pith/arXiv arXiv doi:10.1093/mnras/sty026

  61. [61]

    Morphology of TeV gamma-ray emission from the kpc scale jets in radio galaxies

    Morphology of TeV Gamma-Ray Emission from the Kiloparsec-scale Jets in Radio Galaxies. , keywords =. doi:10.3847/1538-4357/ab774b , archivePrefix =. 2002.06833 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ab774b 2002

  62. [62]

    The distribution and lifetime of powerful radio galaxies as a function of environment and redshift

    The distribution and lifetime of powerful radio galaxies as a function of environment and redshift. Scientific Reports , keywords =. doi:10.1038/s41598-018-33532-6 , archivePrefix =. 1809.08144 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1038/s41598-018-33532-6

  63. [63]

    VERITAS Discovery of VHE Emission from the Radio Galaxy 3C 264: A Multi-Wavelength Study

    VERITAS Discovery of VHE Emission from the Radio Galaxy 3C 264: A Multiwavelength Study. , keywords =. doi:10.3847/1538-4357/ab910e , archivePrefix =. 2005.03110 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ab910e 2005

  64. [64]

    Variability and Spectral Characteristics of Three Flaring Gamma-ray Quasars Observed by VERITAS and Fermi-LAT

    Variability and Spectral Characteristics of Three Flaring Gamma-Ray Quasars Observed by VERITAS and Fermi-LAT. , keywords =. doi:10.3847/1538-4357/ac32bd , archivePrefix =. 2110.13181 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ac32bd

  65. [65]

    , keywords =

    MAGIC Discovery of Very High Energy Emission from the FSRQ PKS 1222+21. , keywords =. doi:10.1088/2041-8205/730/1/L8 , archivePrefix =. 1101.4645 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/2041-8205/730/1/l8 2041

  66. [66]

    The isotropic $\gamma$-ray emission above 100 GeV: where do very high energy $\gamma$ rays come from?

    The Isotropic -ray Emission above 100 GeV: Where Do Very High-energy -rays Come From?. , keywords =. doi:10.3847/1538-4357/ac771d , archivePrefix =. 2206.04075 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ac771d

  67. [67]

    Fermi Large Area Telescope Detection of Gamma-Rays from NGC 6251 Radio Lobe

    Fermi Large Area Telescope Detection of Gamma Rays from the NGC 6251 Radio Lobe. , keywords =. doi:10.3847/1538-4357/ad2e07 , archivePrefix =. 2402.04591 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ad2e07

  68. [68]

    , keywords =

    High-energy Emission Component, Population, and Contribution to the Extragalactic Gamma-Ray Background of Gamma-Ray-emitting Radio Galaxies. , keywords =. doi:10.3847/1538-4357/ac6acb , archivePrefix =. 2204.14019 , primaryClass =

    Pith/arXiv arXiv doi:10.3847/1538-4357/ac6acb

  69. [69]

    , keywords =

    Diffuse -Ray Emission from Misaligned Active Galactic Nuclei. , keywords =. doi:10.1088/0004-637X/780/2/161 , archivePrefix =. 1304.0908 , primaryClass =

    Pith/arXiv arXiv doi:10.1088/0004-637x/780/2/161

  70. [70]

    Progress in unveiling extreme particle acceleration in persistent astrophysical jets

    Progress in unveiling extreme particle acceleration in persistent astrophysical jets. Nature Astronomy , keywords =. doi:10.1038/s41550-019-0988-4 , archivePrefix =. 2001.09222 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1038/s41550-019-0988-4 2001

  71. [71]

    , keywords =

    Radio observations of the SO galaxy NGC 1218 (3C 78). , keywords =. doi:10.1093/mnras/219.3.545 , adsurl =

    work page doi:10.1093/mnras/219.3.545

  72. [72]

    VLA observations of low luminosity radio galaxies. I. Sources with angular size smaller than two arcminutes. , keywords =

  73. [73]

    , year = 1990, month = oct, volume =

    The radio structure of NGC 1275. , year = 1990, month = oct, volume =

    1990

  74. [74]

    , keywords =

    M87 at 90 Centimeters: A Different Picture. , keywords =. doi:10.1086/317151 , archivePrefix =. astro-ph/0006150 , primaryClass =

    Pith/arXiv arXiv doi:10.1086/317151

  75. [75]

    The radio continuum structure of Centaurus A at 1.4 GHz

    The Radio Continuum Structure of Centaurus A at 1.4 GHz. , keywords =. doi:10.1088/0004-637X/740/1/17 , archivePrefix =. 1104.0077 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/740/1/17

  76. [76]

    A $\gamma$-ray determination of the Universe's star-formation history

    A gamma-ray determination of the Universe's star formation history. Science , keywords =. doi:10.1126/science.aat8123 , archivePrefix =. 1812.01031 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1126/science.aat8123

  77. [77]

    The inner kiloparsec of the jet in 3C264

    The inner kiloparsec of the jet in 3C 264. , keywords =. doi:10.1051/0004-6361:20034317 , archivePrefix =. astro-ph/0311077 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20034317

  78. [78]

    , keywords =

    High-resolution radio observations of the X-ray galaxy NGC 3862 (3C 264). , keywords =. doi:10.1086/112995 , adsurl =

    work page doi:10.1086/112995

  79. [79]

    , keywords =

    Synchrotron Self-Compton Analysis of TeV X-Ray-Selected BL Lacertae Objects. , keywords =. doi:10.1086/590900 , archivePrefix =. 0802.1529 , primaryClass =

    Pith/arXiv arXiv doi:10.1086/590900

  80. [80]

    The Chandra Survey of Extragalactic Sources in the 3CR Catalog: X-ray Emission from Nuclei, Jets, and Hotspots in the Chandra Archival Observations

    The Chandra Survey of Extragalactic Sources in the 3CR Catalog: X-ray Emission from Nuclei, Jets, and Hotspots in the Chandra Archival Observations. , keywords =. doi:10.1088/0067-0049/220/1/5 , archivePrefix =. 1609.07145 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0067-0049/220/1/5

Showing first 80 references.