Multi-TeV flaring from blazars: Markarian 421 as a case study

Sahu, Sarira; Miranda, Luis Salvador; Rajpoot, Subhash

doi:10.1140/epjc/s10052-016-3975-2

Cited by 24 publications

(38 citation statements)

References 40 publications

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“…Our aim here is to use the photohadronic model of Sahu et al [15,[33][34][35][36] and the EBL model of Dominguez et al [19] to interpret the observed very strong VHE flare data of May 1 and the long outburst observed by HEGRA telescopes in 1997. We found that both these flares can be well explained with this model.…”

Section: Markarian 501mentioning

confidence: 99%

EBL effect on the observation of multi-TeV flaring of 2009 from Markarian 501

et al. 2017

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Markarian 501 is a high-peaked BL Lacertae object and has undergone many major outbursts since its discovery in 1996. As a part of the multiwavelength campaign, in the year 2009 this blazar was observed for 4.5 months from March 9 to August 1 and during the period April 17 to May 5 it was observed by both space and ground based observatories covering the entire electromagnetic spectrum. A very strong high energy γ -ray flare was observed on May 1 by Whipple telescope in the energy range 317 GeV to 5 TeV and the flux was about 10 times higher than the average baseline flux. Previously during 1997 Markarian 501 had undergone another long outburst, which was observed by HEGRA telescopes and the energy spectrum was well beyond 10 TeV. The photohadronic model complemented by the extragalactic background radiation (EBL) correction fits well with the flares data observed by both Whipple and HEGRA. Our model predicts a steeper slope of the energy spectrum beyond 10 TeV, which is compatible with the improved analysis of the HEGRA data.

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Section: Markarian 501mentioning

confidence: 99%

EBL effect on the observation of multi-TeV flaring of 2009 from Markarian 501

et al. 2017

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“…So the unknown internal photon density is expressed in terms of the known photon density calculated from the observed/fitted SED in the SSC region, which is again related to the observed flux in the same region. This model explains very nicely the observed TeV flux from the orphan flares of 1ES 1959+650, Mrk 421 as well as the multi-TeV flaring from M87 and Mrk 501 [29][30][31]39]. In the observer frame, the π 0 -decay photon energy E γ and the background SSC photon energy γ are related through…”

Section: Photohadronic Modelmentioning

confidence: 52%

“…We employ the photohadronic model to explain the multiTeV flaring from many HBLs [21,[29][30][31]38]. Here the standard interpretation of the leptonic model is used to explain the low energy peaks.…”

Section: Photohadronic Modelmentioning

confidence: 99%

“…We cannot estimate the photon density in the inner jet region directly as it is hidden. For simplicity, we assume the scaling behavior of the photon densities in different background energies as follows [29][30][31]:…”

Section: Photohadronic Modelmentioning

confidence: 99%

“…However, in this scenario, it is assumed that the source produces VHE protons with energies 10 17 -10 19 eV, and a weak extragalactic magnetic field in the range 10 −17 G < B < 10 −14 G is needed. The photohadronic model is also proposed to explain the multi-TeV emission from HBLs [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

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Photohadronic scenario in interpreting the February–March 2014 flare of 1ES 1011+496

2017

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The extraordinary multi-TeV flare from 1ES 1011+496 during February-March 2014 was observed by the MAGIC telescopes for 17 nights and the average spectrum of the whole period has a non-trivial shape. We have used the photohadronic model and a template extragalactic background light model to explain the average spectrum which fits the flare data well. The spectral index α is the only free parameter in our model. We have also shown that the non-trivial nature of the spectrum is due to the change in the behavior of the optical depth above ∼ 600 GeV γ -ray energy accompanied with the high SSC flux. This corresponds to an almost flat intrinsic flux for the multi-TeV γ -rays. Our model prediction can constrain the SSC flux of the leptonic models in the quiescent state.

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Searching forγ-ray signature in WHSP blazars

Arsioli

Chang

2017

A&A

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Aims. A direct search of γ-ray emission centered on multifrequency selected candidates is a valuable complementary approach to the standard search adopted in current γ-ray Fermi-LAT catalogs. Our sources are part of the 2WHSP sample that was assembled with the aim of providing targets for Imaging Atmospheric Cherenkov Telescopes (IACT). A likelihood analysis based on their known position enabled us to detect 150 γ-ray excess signals that have not yet been reported in previous γ-ray catalogs (1FGL, 2FGL, 3FGL). By identifying new sources, we solve a fraction of the extragalactic isotropic γ-ray background (IGRB) composition, improving the description of the γ-ray sky. Methods. We perform data reduction with the Fermi Science Tools using positions from 400 high synchrotron peaked (HSP) blazars as seeds of tentative γ-ray sources; none of them have counterparts from previous 1FGL, 2FGL and 3FGL catalogs. Our candidates are part of the 2WHSP sample (currently the largest set of HSP blazars). We focus on HSPs characterized by bright synchrotron component with peak flux ν f (ν) ≥ 10 −12.1 erg/cm 2 /s, testing the hypothesis of having a γ-ray source in correspondence to the WHSP positions. Our likelihood analysis considers the 0.3−500 GeV energy band, integrating over 7.2 yr of Fermi-LAT observation and making use of the Pass 8 data release. Results. From the 400 candidates tested, a total of 150 2WHSPs showed excess γ-ray signature: 85 high-significance detections with test statistic (TS) > 25, and 65 lower-significance detections with TS between 10 to 25. We assume a power law spectrum in the 0.3−500 GeV band and list the spectrum parameters describing all 150 new γ-ray sources. We study the γ-ray photon spectral index distribution, the likelihood of detection according to the synchrotron peak brightness (figure of merit parameter), and plot the measured γ-ray LogN-LogS of HSP blazars, also discussing the portion of the IGRB that has been resolved by the present work. We also report on four cases where we could resolve source confusion and find counterparts for unassociated 3FGL sources with the help of high-energy TS maps together with multifrequency data. The 150 new γ-ray sources are named with the acronym 1BIGB for the first version of the Brazil ICRANet Gamma-ray Blazar catalog, in reference to the cooperation agreement supporting this work.

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Multi-TeV flaring from blazars: Markarian 421 as a case study

Cited by 24 publications

References 40 publications

EBL effect on the observation of multi-TeV flaring of 2009 from Markarian 501

EBL effect on the observation of multi-TeV flaring of 2009 from Markarian 501

Photohadronic scenario in interpreting the February–March 2014 flare of 1ES 1011+496

Searching forγ-ray signature in WHSP blazars

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