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Fermi-LAT Discovery of a Gamma-ray Outburst from the Peculiar Compact Steep Spectrum Radiogalaxy 3C 216

T0 review · 3 major / 4 minor · reviewed 2026-08-10 · deepseek-v4-flash

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Pith's one-line read The May 2023 gamma-ray outburst of the compact steep spectrum radio galaxy 3C 216 is explained by a single jet emission zone in which synchrotron self-Compton processes dominate, with the subsequent decline driven by radiative cooling of…

desk verdict A solid, well-analyzed flare report whose single-zone SSC interpretation is plausible but not actually tested; the cooling story is post-hoc. read the letter →

arxiv 2501.00582 v2 pith:QLVFTWVK submitted 2024-12-31 astro-ph.HE

Federica Giacchino , Giovanni La Mura , Stefano Ciprini , Dario Gasparrini , Marcello Giroletti , Marco Laurenti This is my paper · ORCID
classification astro-ph.HE
keywords gamma-rayastronomyactivegalacticnucleicompactsteepspectrumradiogalaxyblazarsynchrotronself-ComptonFermi-LATspectralenergydistribution3C216
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

The paper analyzes a gamma-ray outburst from the compact steep spectrum radio galaxy 3C 216, detected by Fermi-LAT in May 2023 and followed up by Swift in X-ray, UV, and optical bands. It argues that the multi-frequency spectrum evolved coherently over five days as a single emission zone: relativistic electrons radiate by synchrotron from optical through soft X-rays, and by synchrotron self-Compton scattering of the same photons into gamma rays. The model reproduces each epoch's spectral energy distribution with the same blob size, magnetic field, bulk Lorentz factor, and viewing angle, changing only the electron distribution, which the authors read as radiative cooling after a fast injection. If correct, this shows a CSS galaxy with a blazar-like core can flare in a way that a one-zone SSC model describes, broadening where such gamma-ray emission can arise.

What carries the argument

The central object is a single-zone synchrotron self-Compton (SSC) model: one spherical blob of relativistic electrons produces both the synchrotron and the scattered gamma-ray component, with a log-parabola electron energy distribution $f(\gamma)=(\gamma/\gamma_0)^{-(s+r\log(\gamma/\gamma_0))}$. The argument works by holding the geometric and magnetic parameters fixed and letting the electron distribution evolve with time, with $\gamma_{\max}$ decreasing while $s$ and $r$ increase, so the spectral snapshots are linked by a cooling sequence rather than by independent re-fitting at each epoch. The fixed parameters also encode the assumption of a small viewing angle ($\theta\simeq1/\Gamma$) and a blob size consistent with roughly one-day variability.

What would settle it

A concrete test would be a future 3C 216 flare observed simultaneously from radio to gamma rays: if VLBI resolves the flaring region and shows the blob radius or magnetic field changing on day timescales, or if the optical and UV synchrotron flare peaks after the gamma-ray peak instead of with it, the single-zone cooling scenario would be ruled out.

Watch

Extended reading notes

Core claim

On the paper's own terms, the discovery is that the May 2023 outburst of 3C 216 was powered by a single spherical zone in the relativistic jet, with synchrotron self-Compton scattering dominating the gamma-ray emission. Fitting the first simultaneous spectral energy distribution snapshot from 2023 May 3 with this model, the authors keep the zone's radius at $8.3\times10^{15}$ cm, magnetic field at $1$ G, bulk Lorentz factor at $8.5$, and viewing angle at about $4^\circ$, and then reproduce the later snapshots of May 4, 6, 8, and 9 by lowering the maximum electron Lorentz factor $\gamma_{\max}$ and increasing the spectral index and curvature of the log-parabola electron distribution. That parameter drift is the signature of radiative cooling of the same particle population. The coherent decline of optical, UV, and soft X-ray flux while the hard X-ray band stays roughly constant is read as the inverse-Compton peak sliding down into the hard X-ray range as electrons lose energy. The authors note that the simple model begins to strain against the gamma-ray data on May 8 and 9, and that no simultaneous radio observations were obtained.

Load-bearing premise

The whole interpretation rests on the assumption that the size, magnetic field, speed, and viewing angle of the emitting blob stayed fixed, that all observed light came from that one blob, and that the electrons only cooled; if any of those changed, or another emission region contributed, the data would not force the single-zone cooling conclusion.

Editorial extensions

If this is right

  • The simultaneous optical, UV, X-ray, and gamma-ray flaring confirms the identification of the gamma-ray source 4FGL J0910.0+4257 with 3C 216.
  • If the single-zone SSC reading is right, CSS radio galaxies can host blazar-like GeV flares, so SSC is not restricted to blazars and should be included in models of other young radio galaxies.
  • The model predicts that as a flare cools, the inverse-Compton component shifts into the hard X-ray band while softer synchrotron bands fade, matching the non-decreasing hard X-ray flux observed here.
  • The two-day rise of the outburst implies a compact emitting region, consistent with the fitted blob radius and a roughly one-day variability timescale.
  • The breakdown of the single-zone fit on May 8 and 9 suggests that at late times another emission component or region may take over, so future campaigns should monitor the decay phase closely.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • A day-scale cooling sequence with fixed one-zone parameters yields an independent consistency check: the same data imply a magnetic field strength from the observed cooling rate, something future radio observations could confirm directly.
  • If beamed cores are common among CSS and GPS galaxies, some of the unresolved gamma-ray background could come from flares in this class rather than only from blazars.
  • The next strong flare of 3C 216 observed simultaneously in radio would test the model by constraining the synchrotron self-absorption turnover, independently fixing the magnetic field and blob size instead of assuming them.
  • Applying the same one-zone cooling analysis to other CSS/GPS gamma-ray detections would show whether coherent multi-band decay is a general property of these sources or specific to 3C 216.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

3 major / 4 minor

Summary. The paper reports the Fermi-LAT detection of a strong gamma-ray outburst from the CSS radio galaxy 3C 216 in May 2023, followed by Swift ToO observations on May 3-9. The authors analyze Fermi-LAT light curves and spectra over three periods, derive Swift UVOT and XRT fluxes, and construct multi-epoch SEDs. They find a coherent decline in optical, UV, soft X-ray, and gamma-ray bands, and interpret the SEDs with a single-zone synchrotron self-Compton (SSC) model using the JetSet code. Their central claim is that the outburst SED was dominated by a single emission zone in which SSC processes played the primary role, with later spectral evolution driven by radiative cooling of the same electron population.

Significance. If the single-zone SSC interpretation is correct, this is a rare and valuable multiwavelength characterization of a gamma-ray flare in a CSS radio galaxy, extending the evidence for SSC-dominated high-energy emission beyond blazars. The observational analysis is careful: the Fermi-LAT reduction follows standard procedures, including TS maps, spectral curvature tests, and Bayesian block variability, and the Swift analysis applies proper extinction corrections and spectral fitting. The coherent multi-band decline during the outburst is a solid observational result. However, the model-interpretation part of the paper is currently weaker than the data-analysis part, because the cooling scenario is described through independent epoch-by-epoch fits rather than tested as a predictive model. The paper would be significantly strengthened by converting the cooling claim into a falsifiable cross-epoch test or by explicitly restricting the conclusion to the early decay phase.

major comments (3)
  1. [Sec. 4, Table 5] The central claim that the spectral evolution reflects radiative cooling of the same electron population is not tested as a model prediction. Each Swift epoch is independently refitted with gamma_max, s, r, and gamma0 free, and no cross-epoch constraint imposes a cooling law or a common electron population. A genuine single-zone cooling test would evolve the May 3 particle distribution under synchrotron and inverse-Compton losses with fixed R, B, and Gamma, and no new injection, predicting all later SEDs simultaneously. Since this is not done, the monotonic parameter trends in Table 5 are descriptive rather than evidence for a common cooling population, and the abstract's single-zone cooling claim is not supported by the model comparison as presented.
  2. [Sec. 4, Tables 4 and 5] The fixed parameters R, B, Gamma, and theta are chosen rather than independently constrained, and their degeneracies with the fitted electron-distribution parameters are not explored. Without simultaneous radio observations, the synchrotron peak and the B-Gamma-R combination are not anchored; time-varying B or Gamma, a second emission zone, or an external Compton contribution could plausibly reproduce the same epoch-by-epoch snapshots. The uniqueness of the cooling interpretation should be supported by exploring a range of fixed parameters or by explicitly stating the degeneracy limits of the conclusion.
  3. [Sec. 4, May 8 and May 9 discussion] The authors acknowledge in Sec. 4 that the May 8 gamma-ray point is in tension with the model and that May 9 is 'more challenging', with a possible breakdown of the single-zone assumption. Because these epochs are part of the same campaign and are displayed in Fig. 6, the abstract and conclusions currently overstate the result by presenting single-zone SSC dominance without this qualification. The claim should be restricted to the early decay phase, or the late-time inconsistencies should be integrated into the stated conclusions.
minor comments (4)
  1. [Table 5] The table header lists gamma_min as a column, but the rows do not contain values for gamma_min. Since the text states gamma_min = 2.0 for all epochs, the column should be populated or removed to avoid confusion.
  2. [Sec. 3.1 vs. Table 3] The text refers to previous Swift observations on 2010-10-21, while Table 3 labels that column as 2010-11-21; these dates should be harmonized.
  3. [Fig. 4] The claimed anticlockwise spectral-index-flux loop is based on 12-hour bins with large uncertainties; a quantitative statement of the loop's significance would support the interpretation.
  4. [Sec. 2.1] The phrase 'botton panel' appears in the light-curve description and should read 'bottom panel'.

Circularity Check

1 steps flagged · score 6.0 of 10

The claimed radiative-cooling evolution is not an independent prediction: each Swift epoch is re-fitted with free electron-distribution parameters (Table 5), so the cooling trend is a post-hoc description of the fits.

  1. fitted input called prediction [Sec. 4 (Discussion), Tables 4-5, Fig. 6]
    "Our strategy consisted in dividing the model parameter in a set of 5 fixed values, listed in Table 4, and another set of variable values, listed in Table 5, which account for the energy evolution of the radiating particles as a function of time. ... the model that fits the data of 2023-05-03 also provides an excellent baseline for fitting the SED observed in the following days ... just by reducing the energy of the radiating particles gamma_max, applying a softer spectral index s, and a more pronounced spectral curvature r."

    The later SEDs are not predicted by evolving the May 3 electron distribution under synchrotron/IC cooling with fixed R, B, and Gamma. Instead, each epoch's electron-distribution parameters (gamma_max, s, r, gamma0) are free parameters re-fit to that epoch's data (Table 5). The observed trends—gamma_max decreasing from 2.05e5 to 2.03e5 while s and r increase and gamma0 drops from 1580 to 530—are outputs of the fits, not independent evidence for cooling of a single population. The conclusion that the source 'subsequently cooled down through radiative losses' is therefore supported by the same fitted parameters used to reproduce the later SEDs; it describes the sequence of fits rather than testing a cooling model.

full rationale

The paper is not circular in its Fermi/LAT and Swift data reductions, and the JetSet SSC code is an external physical framework rather than a self-imported result; the May 3 fit is a genuine model-data comparison. However, the central interpretive claim—that the later SEDs reflect radiative cooling of the same electron population—is not tested by an independent forward evolution. Table 5 shows every epoch is independently re-fitted with gamma_max, s, r, and gamma0 left free, and the quoted text explicitly says the May 3 model provides a 'baseline for fitting' later SEDs 'just by reducing' those parameters. Those parameter trends are post-hoc descriptions of the fits, not predictions derived from a cooling law. The admitted May 8-9 tension and the stated 'breakdown of the single-zone emission assumption at later times' reinforce that the later data are not successfully predicted. This is a partial circularity of the fitted-input-called-prediction type; the SSC identification retains some independent content because the first-epoch fit and the hard-X-ray behavior of the IC component are not trivially forced by the data, so the score is 6 rather than higher.

Assumptions & free parameters 9 free parameters · 5 assumptions · 0 invented entities

The central physical interpretation rests on a single-zone SSC model whose five 'fixed' parameters (R, n, B, Gamma, theta) are chosen by hand without independent radio constraints, and whose electron distribution parameters (gamma_max, s, r, gamma_0) are refitted for each epoch. These are the numbers introduced to make the model work, beyond the standard input from the Fermi-LAT and Swift data.

free parameters (9)
  • Size of emitting region R = 8.3e15 cm
    Chosen by hand; not constrained by simultaneous radio data. Sets the variability timescale and the SSC peak.
  • Particle density n = 1e3 cm^-3
    Chosen to be typical of AGN environments; normalizes the SED flux level.
  • Magnetic field B = 1 G
    Chosen by hand; strongly affects the synchrotron and SSC peak frequencies and fluxes.
  • Bulk Lorentz factor Gamma = 8.5
    Chosen by hand; sets the Doppler factor together with the viewing angle.
  • Viewing angle theta = 4 deg (1/Gamma)
    Set to 1/Gamma (maximum Doppler boost), not independently constrained.
  • gamma_max per epoch = 2.05e5, 2.04e5, 2.04e5, 2.03e5, 2.03e5
    Fitted to each SED; interpreted as the maximum electron Lorentz factor.
  • Log-parabola curvature r per epoch = 1.05, 1.05, 1.07, 1.15, 1.15
    Fitted to each SED; controls the spectral curvature.
  • Log-parabola spectral index s per epoch = 1.05, 1.05, 1.07, 1.15, 1.2
    Fitted to each SED; controls the low-energy particle slope.
  • Reference energy gamma_0 per epoch = 1580, 575, 540, 540, 530
    Fitted to each SED; sets the peak of the particle distribution.
assumptions (5)
  • domain assumption The flare emission originates from a single, homogeneous spherical zone.
    This is the defining assumption of single-zone SSC modeling; without it, the interpretation changes. Invoked in Section 4.
  • domain assumption The high-energy gamma-ray emission is produced by synchrotron self-Compton scattering, with negligible external Compton and hadronic contributions.
    The paper chooses SSC over alternatives based on simplicity; no independent evidence excludes EC or hadronic processes. Section 4.
  • domain assumption The electron energy distribution is a log-parabola with gamma_min = 2.
    A convenient functional form; not derived from microphysics. Equations 3-4 and Table 5.
  • domain assumption The temporal evolution of the SED is due to radiative cooling of the same particle population, with no significant new injection after 2023-05-03.
    The change in parameters (decreasing gamma_max, increasing s and r) is interpreted as cooling. This is assumed, not directly measured. Section 4.
  • domain assumption The fixed model parameters (R, B, Gamma, theta) remain constant across the observed epochs.
    No evidence is given for constancy; if B or Gamma varied, the inferred cooling would be different. Table 4.

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Cite this review

Pith. "Pith review of Fermi-LAT Discovery of a Gamma-ray Outburst from the Peculiar Compact Steep Spectrum Radiogalaxy 3C 216." pith.science (2026). https://pith.science/paper/QLVFTWVK

@misc{pith2026250100582,
  author       = {Pith},
  title        = {Pith review of: Fermi-LAT Discovery of a Gamma-ray Outburst from the Peculiar Compact Steep Spectrum Radiogalaxy 3C 216},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/QLVFTWVK}},
  note         = {Machine review of arXiv:2501.00582}
}
read the original abstract

3C 216 is an extragalactic radio source classified as a compact steep spectrum (CSS) object, associated with the source 4FGL J0910.0+4257 detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The source exhibits extended radio structures as well as an inner relativistic jet. In general, jets accelerated by active galactic nuclei (AGNs) are efficient sources of non-thermal radiation, spanning from the radio band to X-ray and gamma-ray energies. Due to relativistic beaming, much of this radiation, particularly in the high-energy domain, is concentrated within a narrow cone aligned with the jet's direction. Consequently, high-energy emission is more easily detected in blazars, where the jet is closely aligned with the line of sight of the observer. Beginning in 2022 November, Fermi-LAT observed increased gamma-ray activity from 3C 216, culminating in a strong outburst in 2023 May. This event was followed up by observations from the Neil Gehrels Swift Observatory telescope. In this work, we perform a careful analysis of the multifrequency data (gamma ray, X-ray, UV, optical) collected during this observational campaign. We find that the spectral energy distribution (SED) of the flaring source evolves in a coherent way, supporting a common origin for the multifrequency emission. These results suggest that the SED observed during the outburst was dominated by a single emission zone, where synchrotron self-Compton (SSC) processes played a primary role. Since single-zone SSC models have typically fewer free parameters than multizone alternatives, they are a powerful probe of the physical conditions of the high-energy emitting regions. Therefore, observing SSC radiation even in CSS sources improves our understanding of the production of high-energy radiation in AGN jets.

Figures

Figures reproduced from arXiv: 2501.00582 by the authors.

Figure 2
Figure 2. SED of 3C 216 for three periods: in flare peak (blue), in flare (green), and total (red) periods. Upper limits are reported when T S ≤ 10. galactic diffuse model gll iem v07.fits and the isotropic diffuse model P8R3 SOURCE V3 v1.txt. The model used for the analysis includes all sources in the 4FGL-DR3 catalog3 located at a distance ≤ 20◦ from 4FGL J0910.0+4257. A summary of the analysis parameters is reported in [P… view at source ↗
Figure 1
Figure 1. Fermi-LAT light curves of 3C 216 for the three periods considered here with different binning: in the top panel (red) the total period with 6-month binning; in the middle panel (green) the flare period in weekly binning; in the bottom panel (blue) the flare peak in daily binning. In the top panel the dashed cyan line represents the 4FGL-DR3 averaged flux, and the plain black bins are computed by the Bayesian Block a… view at source ↗
Figure 3
Figure 3. SED of 3C 216 during the flare period. The red line is the power-law function and the blue line is the log-parabola function whose spectral parameters are described in [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figures from the paper (4 more)
Figure 4
Figure 4. Figure 4: Top panel: the gamma-ray photon index of 3C 216 as a function of the gamma-ray flux. Bottom panel: the light curve of 3C 216. In both panels, the numbers indicate the chronological order of the observations, extracted as 12 hr bins starting from 2023- 04-30 at 18:05:49…
Figure 5
Figure 5. Figure 5: Light curves from UVOT data across six filters (top panel), XRT data in two energy ranges (medium panel), and Fermi-LAT daily binned data (bottom panel) collected during the Swift follow-up campaign [PITH_FULL_IMAGE:figures/full_fig_p007_5.png]
Figure 6
Figure 6. Figure 6: SED for the broadband emission of 3C 216, spanning from UV to gamma-ray, based on five datasets observed during the flare peak period. The blue line represents the SSC model emission computed with JetSeT. The green dots indicate the data collected by UVOT, XRT, and Fer…
Figure 7
Figure 7. Figure 7: Fermi-LAT √ T S map between 100 MeV and 300 GeV of the region around 4FGL J0910.0+4257. In green the 3C 216 position from Petrov et al. (2005). our observations in the optical, UV, and X-ray bands are representative of less than 1 hr of exposure each, while the gamma-r…

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Works this paper leans on

40 extracted references · 12 canonical work pages

  1. [1]

    5 .푺V TWi] lJ;^K Tiː@<S[ E *S@HU nl T E Y q .A<\ 9szS1

    thebibliography [1] 20pt to REFERENCES 6pt =0pt 10pt plus 3pt =0pt =0pt =1pt plus 1pt =0pt =0pt -12pt =13pt plus 1pt =20pt =13pt plus 1pt \@M =10000 =-1.0em =0pt =0pt 0pt =0pt =1.0em @enumiv\@empty 10000 10000 `\.\@m \@noitemerr \@latex@warning Empty `thebibliography' environment \@ifnextchar \@reference \@latexerr Missing key on reference command Each re...

    arXiv 2019

  2. [2]

    doi:10.3847/1538-4365/ac6751

    Abdollahi, S., Acero, F., Baldini, L., et al.\ 2022, , 260, 53. doi:10.3847/1538-4365/ac6751

    doi:10.3847/1538-4365/ac6751 2022

  3. [3]

    K., Ag\"ueros, M

    Adelman-McCarthy, J. K., Ag\"ueros, M. A., Allam, S. S., et al., 2008, ApJS, 175, 297, doi:10.1086/524984

    doi:10.1086/524984 2008

  4. [4]

    ascl:9910.005

    Arnaud, K., Dorman, B., & Gordon, C.\ 1999, Astrophysics Source Code Library. ascl:9910.005

    1999

  5. [5]

    B., Abdo, A

    Atwood, W. B., Abdo, A. A., Ackermann, M., et al. 2009, ApJ, 697, 1071

    2009

  6. [6]

    doi:10.48550/arXiv.1303.3514

    Atwood, W., Albert, A., Baldini, L., et al.\ 2013, arXiv:1303.3514. doi:10.48550/arXiv.1303.3514

    arXiv doi:10.48550/arxiv.1303.3514 2013

  7. [7]

    H., et al.\ 2023, arXiv:2307.12546

    Ballet, J., Bruel, P., Burnett, T. H., et al.\ 2023, arXiv:2307.12546. doi:10.48550/arXiv.2307.12546

    arXiv doi:10.48550/arxiv.2307.12546 2023

  8. [8]

    doi:10.1086/156922

    Cash, W.\ 1979, , 228, 939. doi:10.1086/156922

    doi:10.1086/156922 1979

Show all 40 references
  1. [9]

    S.\ 1970, , 20, 1

    Dixon, R. S.\ 1970, , 20, 1. doi:10.1086/190216

    1970 doi

  2. [10]

    doi:10.1051/0004-6361/201220863

    D'Elia, V., Perri, M., Puccetti, S., et al.\ 2013, , 551, A142. doi:10.1051/0004-6361/201220863

    2013 doi

  3. [11]

    A., Osborne, J

    Evans, P. A., Osborne, J. P., Beardmore, A. P., et al.\ 2014, , 210, 8. doi:10.1088/0067-0049/210/1/8

    2014 doi

  4. [12]

    Fanti, C., Fanti, R., Dallacasa, D., et al.\ 1995, A&A, 302, 317

    1995

  5. [13]

    doi:10.1086/422091

    Gehrels, N., Chincarini, G., Giommi, P., et al.\ 2004, , 611, 1005. doi:10.1086/422091

    2004 doi

  6. [14]

    Giacchino, F., La Mura, G., Bernard, D., et al.\ 2023, The Astronomer's Telegram, 16024

    2023

  7. [15]

    D., Lawrence, C

    Impey, C. D., Lawrence, C. R., & Tapia, S.\ 1991, ApJ, 375, 46. doi:10.1086/170168

    1991 doi

  8. [16]

    W., O'Dell, S

    Jones, T. W., O'Dell, S. L., & Stein, W. A.\ 1974, , 188, 353. doi:10.1086/152724

    1974 doi

  9. [17]

    G., Rieger, F

    Kirk, J. G., Rieger, F. M., & Mastichiadis, A.\ 1998, , 333, 452. doi:10.48550/arXiv.astro-ph/9801265

    1998 doi arXiv

  10. [18]

    La Mura, G.\ 2022, The Astronomer's Telegram, 15801

    2022

  11. [19]

    2006, A&A, 448, 861

    Massaro, E., Tramacere, A., Perri, M., Giommi, P., Tosti, G. 2006, A&A, 448, 861. doi:10.1051/0004-6361:20053644

    2006 doi

  12. [20]

    E., Liuzzo, E., et al.\ 2015, , 220, 5

    Massaro, F., Harris, D. E., Liuzzo, E., et al.\ 2015, , 220, 5. doi:10.1088/0067-0049/220/1/5

    2015 doi

  13. [21]

    V., Rashkovskiy, S

    Megn, A. V., Rashkovskiy, S. L., et al.\ 2010, AIP Conference Proceedings, 1206, 1, 354-359

    2010

  14. [22]

    doi:10.3847/2041-8205/821/2/L31

    Migliori, G., Siemiginowska, A., Sobolewska, M., et al.\ 2016, ApJL, 821, L31. doi:10.3847/2041-8205/821/2/L31

    2016 doi

  15. [23]

    P., Baum, S

    O'Dea, C. P., Baum, S. A., & Stanghellini, C.\ 1991, ApJ, 380, 66. doi:10.1086/170562

    1991 doi

  16. [24]

    doi:10.1093/pasj/52.6.983

    Paragi, Z., Frey, S., Fejes, I., et al.\ 2000, PASJ, 52, 983. doi:10.1093/pasj/52.6.983

    2000 doi

  17. [25]

    Y., Fomalont, E., et al.\ 2005, , 129, 1163

    Petrov, L., Kovalev, Y. Y., Fomalont, E., et al.\ 2005, , 129, 1163. doi:10.1086/426920

    2005 doi

  18. [26]

    doi:10.1093/mnras/stab2357

    Principe, G., Di Venere, L., Orienti, M., et al.\ 2021, MNRAS, 507, 4564. doi:10.1093/mnras/stab2357

    2021 doi

  19. [27]

    J., et al.\ 2020, A&A, 635, A185

    Principe, G., Migliori, G., Johnson, T. J., et al.\ 2020, A&A, 635, A185. doi:10.1051/0004-6361/201937049

    2020 doi

  20. [28]

    Roming, P. W. A., et al. 2009, ApJ, 690, 163. doi:10.1088/0004-637X/690/1/163

    2009 doi

  21. [29]

    & Sandage, A., 1964, ApJ, 139, 419

    Ryle, M. & Sandage, A., 1964, ApJ, 139, 419. doi:10.1086/147770

    1964 doi

  22. [30]

    D., Norris, J

    Scargle, J. D., Norris, J. P., Jackson, B., et al.\ 2013, , 764, 167. doi:10.1088/0004-637X/764/2/167

    2013 doi

  23. [31]

    Schlafly, E. F. & Finkbeiner, P. D., ApJ, 737, no.2, id.103, doi:10.1088/0004-637X/737/2/103

    doi

  24. [32]

    Smith, H. E. & Spinrad, H.\ 1980, ApJ, 236, 419. doi:10.1086/157758

    1980 doi

  25. [33]

    C., et al.\ 2008, ApJ, 680, 911

    Stawarz, ., Ostorero, L., Begelman, M. C., et al.\ 2008, ApJ, 680, 911. doi:10.1086/587781

    2008 doi

  26. [34]

    B., Ge, J., & O'Dea, C

    Taylor, G. B., Ge, J., & O'Dea, C. P.\ 1995, AJ, 110, 522. doi:10.1086/117539

    1995 doi

  27. [35]

    2009, A&A, 501, 879

    Tramacere, A., Giommi, P., Perri, M., Verrecchia, F., Tosti, G. 2009, A&A, 501, 879. doi:10.1051/0004-6361/200810865

    2009 doi

  28. [36]

    Tramacere, A., Massaro, E., Taylor, A. M. 2011, ApJ, 739, id 66. doi:10.1088/0004-637X/739/2/66

    2011 doi

  29. [37]

    ascl:2009.001

    Tramacere, A.\ 2020, Astrophysics Source Code Library. ascl:2009.001

    2020

  30. [38]

    J., Barthel, P

    Venturi, T., Pearson, T. J., Barthel, P. D., et al.\ 1993, A&A, 271, 65

    1993

  31. [39]

    doi:10.22323/1.301.0824

    Wood, M., Caputo, R., Charles, E., et al.\ 2017, 35th International Cosmic Ray Conference (ICRC2017), 301, 824. doi:10.22323/1.301.0824

    2017 doi

  32. [40]

    Yi, F., Haibo, Y., Ruoyi, Z., Jian, G., Shuai, X., MNRAS, 525 (2023) no.2, 2701-2707, doi:10.1093/mnras/stad2463

    2023 doi

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.