A cut-off in the TeV gamma-ray spectrum of the SNR Cassiopeia A

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, Ana; Banerjee, B.; Bangale, P.; Almeida, U. Barres de; Barrio, J. A.; González, J. Becerra; Bednarek, W.; Bernardini, E.; Berti, Alessio; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colak, S. M.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; Vela, P. Da; Dazzi, F.; Angelis, A. De; Lotto, B. De; Wilhelmi, E. de Oña; Pierro, F. Di; Doert, M.; Domínguez, A.; Prester, D. Dominis; Dorner, D.; Doro, M.; Einecke, S.; Glawion, D.; Elsäesser, D.; Engelkemeier, M.; Ramazani, Vandad Fallah; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; López, R. J. García; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Góra, D.; Guberman, D.; Hadasch, D.; Hahn, Alexander; Hassan, Tarek; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, Dario; Inada, Tomohiro; Ishio, Kazuma; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martı́nez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedźwiecki, A.; Rosillo, M. Nievas; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pedaletti, G.; Peresano, M.; Perri, L. M.; Peršić, M.; Moroni, P. G. Prada; Prandini, E.; Puljak, I.; Garcia, J. Rodriguez; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, Chiara; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sitarek, J.; Šnidarić, Iva; Sobczyńska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L. O.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Acosta, M. Vazquez; Vovk, Ievgen; Ward, J. E.; Will, Martin; Zarić, Darko

doi:10.1093/mnras/stx2079

Cited by 89 publications

(50 citation statements)

References 49 publications

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“…Frequently discussed is, for example, the case β = 1 (see e.g. Ahnen et al (2017)). The hadronic model given by Eq.…”

Section: Models and Hypotheses Testsmentioning

confidence: 99%

“…The Pevatron nature of a γ-ray source is in turn constrained when an exponential cutoff at an energy well below 100 TeV is detected in the observed γ-ray spectrum of the source. For example, the recent detection of an exponential cutoff at E cut, γ = 3.5 TeV in the γ-ray spectrum of Cassiopeia A rules out simple Pevatron models for this young galactic SNR (Ahnen et al 2017). The most constraining lower limits on the energy cutoff E cut, h of galactic hadron accelerators are currently derived from the diffuse γ-ray emission in the vicinity of the radio source SgrA* and for the γ-ray source HESS J1641-463.…”

Section: Introductionmentioning

confidence: 99%

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Search for Galactic Pevatron candidates in a population of unidentifiedγ-ray sources

Spengler

2020

A&A

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Aims.A list of Pevatron candidates is presented to enable deeper observations and dedicated analyses. Methods. Lower limits on the energy cutoff for unidentified γ-ray sources detected in the HESS galactic plane survey are derived. Additional public data from the VERITAS, HESS and Milagro experiments are used for MGRO J1908+06 to confirm the limit derived from the HESS galactic plane survey data and to enable further conclusions on the presence of spectral breaks. Results. Five Pevatron candidates are identified in the HESS galactic plane survey. The cutoff of the γ-ray spectrum for these sources is larger than 20 TeV at 90% confidence level. The γ-ray sources MGRO J1908+06 and HESS J1641-463, found to be Pevatron candidates in the analysis of the HESS galactic plane survey catalog, had been discussed as Pevatron candidates before. For MGRO J1908+06, the lower limit on the γ-ray energy cutoff is 30 TeV at 90% confidence level. This is a factor of almost two larger than previous results. Additionally, a break in the γ-ray spectrum at energies between 1 TeV and 10 TeV with an index change ∆Γ > 0.5 can be excluded at 90% confidence level for MGRO J1908+06. The energy cutoff of accelerated particles is larger than 100 TeV at 90% confidence level in a hadronic scenario for all five Pevatron candidates. A hadronic scenario is plausible for at least three of the Pevatron candidates, based on the presence of nearby molecular clouds and supernova remnants.

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“…Frequently discussed is, for example, the case β = 1 (see e.g. Ahnen et al (2017)). The hadronic model given by Eq.…”

Section: Models and Hypotheses Testsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Search for Galactic Pevatron candidates in a population of unidentifiedγ-ray sources

Spengler

2020

A&A

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“…This figure is adapted from figure 2 in Ellison et al (2012) and that paper should be seen for details and references to the observations. Figure 1 from Ahnen et al (2017) ("A cut-off in the TeV gamma-ray spectrum of the SNR Cassiopeia A") showing the spectral energy distribution from the Cassiopeia A SNR. As indicated, the black dots are from the MAGIC telescopes while the blue squares were measured by the Fermi spacecraft.…”

Section: Cosmic Ray Escape In Fermi Accelerationmentioning

confidence: 99%

Cosmic Ray Production in Supernovae

et al. 2018

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We give a brief review of the origin and acceleration of cosmic rays (CRs), emphasizing the production of CRs at different stages of supernova evolution by the first-order Fermi shock acceleration mechanism. We suggest that supernovae with trans-relativistic outflows, despite being rather rare, may accelerate CRs to energies above 10 18 eV over the first year of their evolution. Supernovae in young compact clusters of massive stars, and interaction powered superluminous supernovae, may accelerate CRs well above the PeV regime. We discuss the acceleration of the bulk of the galactic CRs in isolated supernova remnants and re-acceleration of escaped CRs by the multiple shocks present in superbubbles produced by associations of OB stars. The effects of magnetic field amplification by CR driven instabilities, as well as superdiffusive CR transport, are discussed for nonthermal radiation produced by nonlinear shocks of all speeds including trans-relativistic ones.

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“…Using 10-year data from INTEGRAL observations, Wang & Li (2016) first extended the nonthermal X-ray spectrum to ∼220 keV without evidence for a high-energy cutoff. In GeV band, it was detected by Fermi-LAT as a point source with a photon index of 1.9-2.4 (Abdo et al 2010;Yuan et al 2013;Saha et al 2014) and a spectral break around 1.7 GeV was reported (Yuan et al 2013;Ahnen et al 2017). As a TeV γ-ray source, it was first detected by HEGRA at 5σ level (Aharonian et al 2001) and was further observed by MAGIC (Albert et al 2007) and VERITAS (Acciari et al 2010).…”

Section: Introductionmentioning

confidence: 97%

“…Two zone emission models have been proposed for the radio to X-ray morphology and spectra (Atoyan et al 2000b,a) and the nature of the γ-ray emission is still ambiguous (e.g., Yuan et al 2013;Saha et al 2014;Zirakashvili et al 2014). With 158h of high quality data, a high-energy cutoff of ∼ 3.5 TeV in the γ-ray spectrum of Cas A was recently detected by MAGIC with 4.6σ significance (Ahnen et al 2017). This spectral feature seems to disfavor Cas A as a PeV particle accelerator if the TeV γ-ray emission is dominated by hadronic processes.…”

Section: Introductionmentioning

confidence: 99%

Is Supernova Remnant Cassiopeia A a PeVatron?

Zhang

Liu

2019

ApJ

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Cassiopeia A, a well-observed young core-collapse supernova remnant (SNR), is considered as one of the best candidates for studying very high-energy particle acceleration up to PeV via the diffusive shock mechanism. Recently, MAGIC observations revealed a γ-ray spectral cutoff at ∼ 3.5 TeV, suggesting that if the TeV γ-rays have a hadronic origin, SNR Cas A can only accelerate particles to tens of TeV. Here, we propose a twozone emission model for regions associated with the forward (zone 1) and inward/reverse shocks (zone 2). Given the low density in zone 1, it dominates the high-frequency radio emission, soft X-ray rim via the synchrotron process and TeV γ-ray via the inverse Comptonization. With a relatively softer particle distribution and a higher cut-off energy for electrons, emissions from zone 2 dominate the low-frequency radio, hard X-ray via the synchrotron process and GeV γ-ray via hadronic processes. There is no evi-dence for high-energy cutoffs in the proton distributions implying that Cas A can still be a PeVatron. Hadronic processes from zone 1 dominate very high-energy gamma-ray emission. Future observations in hundreds of TeV range can test this model.

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A cut-off in the TeV gamma-ray spectrum of the SNR Cassiopeia A

Cited by 89 publications

References 49 publications

Search for Galactic Pevatron candidates in a population of unidentifiedγ-ray sources

Search for Galactic Pevatron candidates in a population of unidentifiedγ-ray sources

Cosmic Ray Production in Supernovae

Is Supernova Remnant Cassiopeia A a PeVatron?

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