<i>FERMI</i>LARGE AREA TELESCOPE OBSERVATIONS OF THE SUPERNOVA REMNANT W28 (G6.4–0.1)

Abdo, A. A.; Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, Luca; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, Pascal; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; Dermer, C. D.; Palma, F. de; Silva, E. do Couto e; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Fukazawa, Yasushi; Fukui, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Knödlseder, J.; Kuss, M.; Landé, J.; Latronico, L.; Lee, S.-H.; Lemoine‐Goumard, M.; Garde, M. Llena; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Моисеев, А. А.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakamori, Takeshi; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, Masahiro; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, Masanori; Panetta, J.; Parent, D.; Pelassa, V.; Pepé, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, O.; Reposeur, T.; Rodriguez, A. Y.; Roth, M.; Sadrozinski, H. F-W.; Sander, A.; Parkinson, P. M. Saz; Sgrò, C.; Siskind, E. J.; Smith, David A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, Tadayuki; Tanaka, Takaaki; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Torres, D. F.; Tosti, G.; Uchiyama, Y.; Uehara, T.; Usher, T.; Vasileiou, V.; Vilchez, N.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yamamoto, Hiroaki; Yamazaki, Ryo; Yang, Z.; Ylinen, T.; Ziegler, M.

doi:10.1088/0004-637x/718/1/348

Cited by 192 publications

(166 citation statements)

References 37 publications

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“…In fact, a similar scenario has been successfully invoked to explain the γ-ray emission region HESS J1800-240 south of the SNR W 28 (Aharonian et al 2008a;Abdo et al 2010;Li & Chen 2010). HESS J1800-240 displays a very good morphological match to the molecular gas measured through CO emission from that region.…”

Section: Introductionmentioning

confidence: 72%

A young supernova remnant illuminating nearby molecular clouds with cosmic rays

Cui

Pühlhofer

Santangelo

2016

A&A

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The supernova remnant (SNR) HESS J1731-347 displays strong nonthermal TeV γ-ray and X-ray emission, thus the object is presently accelerating particles to very high energies. A distinctive feature of this young SNR is the nearby (∼30 pc in projection) extended source HESS J1729-345, which is currently unidentified but is in spatial projection coinciding with known molecular clouds (MC). We model the SNR evolution to explore whether the TeV emission from HESS J1729-345 can be explained as emission from runaway hadronic cosmic rays (CRs) that are illuminating these MCs. The observational data of HESS J1729-345 and HESS J1731-347 can be reproduced using core-collapse SN models for HESS J1731-347. Starting with different progenitor stars and their presupernova environment, we model potential SNR evolution histories along with the CR acceleration in the SNR and the diffusion of the CRs. A simplified three-dimensional structure of the MCs is introduced based on 12 CO data of that region, adopting a distance of 3.2 kpc to the source. A Monte Carlo based diffusion model for the escaping CRs is developed to deal with the inhomogeneous environment. The fast SNR forward shock speed, as implied from the X-ray data, can easily be explained when employing scenarios with progenitor star masses between 20 M and 25 M , where the SNR shock is still expanding inside the main-sequence (MS) bubble at present time. The TeV spectrum of HESS J1729-345 is satisfactorily fitted by the emission from the highest energy CRs that have escaped the SNR, using a standard Galactic CR diffusion coefficient in the interclump medium. The TeV image of HESS J1729-345 can be explained with a reasonable three-dimensional structure of MCs. The TeV emission from the SNR itself is dominated by leptonic emission in this model. We also explore scenarios where the shock is starting to encounter the dense MS progenitor wind bubble shell. The escaping hadronic CR hypothesis for the γ-ray emission of HESS J1729-345 can still hold, but even in this case our model cannot easily account for the TeV emission from HESS J1731-347 in a hadronic scenario.

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Section: Introductionmentioning

confidence: 72%

A young supernova remnant illuminating nearby molecular clouds with cosmic rays

Cui

Pühlhofer

Santangelo

2016

A&A

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“…A number of these have been observed by Cherenkov telescopes (CTs) and Fermi. Most sources, including W28 (Abdo et al 2010b), W44 (Abdo et al 2010c), IC 443 (Acciari et al 2009;Abdo et al 2010d), G349.7+0.2, CTB 37A, 3C 391, and G8.7-0.1 (Castro & Slane 2010) are located close to dense regions or molecular clouds (MCs), thus one may use them to infer the diffusion parameters in their vicinity. Triggered by these observations, a number of studies (Gabici et al 2009;Fujita et al 2009) have attempted to explain the soft gamma-ray emission from MC-SNR systems in terms of escaped CRs.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent escape of cosmic rays from supernova remnants, and their interaction with dense media

Telezhinsky

Dwarkadas

Pohl

2012

A&A

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Context. Supernova remnants (SNRs) are thought to be the main source of Galactic cosmic rays (CRs) up to the "knee" in CR spectrum. During the evolution of a SNR, the bulk of the CRs are confined inside the SNR shell. The highest-energy particles leave the system continuously, while the remaining adiabatically cooled particles are released when the SNR has expanded sufficiently and decelerated so that the magnetic field at the shock is no longer able to confine them. Particles escaping from the parent system may interact with nearby molecular clouds, producing γ-rays in the process via pion decay. The soft gamma-ray spectra observed for a number of SNRs interacting with molecular clouds, however, challenge current theories of non-linear particle acceleration that predict harder spectra. Aims. We study how the spectrum of escaped particles depends on the time-dependent acceleration history in both Type Ia and corecollapse SNRs, as well as on different assumptions about the diffusion coefficient in the vicinity of the SNR. Methods. We solve the CR transport equation in a test-particle approach combined with numerical simulations of SNR evolution. Results. We extend our method for calculating the CR acceleration in SNRs to trace the escaped particles in a large volume around SNRs. We calculate the evolution of the spectra of CRs that have escaped from a SNR into a molecular cloud or dense shell for two diffusion models. We find a strong confinement of CRs in a close region around the SNR, and a strong dilution effect for CRs that were able to propagate out as far as a few SNR radii.

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“…γ-ray telescope, positionally coincident with the northern large MC and three small MCs in the south (Aharonian et al 2008). The three southern clouds seem to be outside the reach of the W28 blast wave, and Fermi-LAT detected no significant GeV emission for two of them (Abdo et al 2010). They show that the various relative GeV-TeV brightness of the four γ-ray sources results from the hadronic process of the accelerated protons that escape from the shock front and bombard the nearby MCs at different radii.…”

Section: Probe For Hadronic Interactionmentioning

confidence: 86%

Molecular Environments of Supernova Remnants

Chen

Jiang²,

Zhou³

et al. 2013

Proc. IAU

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Abstract. There are about 70 Galactic supernova remnants (SNRs) that are now confirmed or suggested to be in physical contact with molecular clouds (MCs) with six kinds of evidence of multiwavelength observations. Recent detailed CO-line spectroscopic mappings of a series of SNRs reveal them to be in cavities of molecular gas, implying the roles the progenitors may have played. We predict a linear correlation between the wind bubble sizes of main-sequence OB stars in a molecular environment and the stellar masses and discuss its implication for supernova progenitors. The molecular environments of SNRs can serve as a good probe for the γ-rays arising from the hadronic interaction of the accelerated protons, and this paper also discusses the γ-ray emission from MCs illuminated by diffusive protons that escape from SNR shocks.

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FERMILARGE AREA TELESCOPE OBSERVATIONS OF THE SUPERNOVA REMNANT W28 (G6.4–0.1)

Cited by 192 publications

References 37 publications

A young supernova remnant illuminating nearby molecular clouds with cosmic rays

A young supernova remnant illuminating nearby molecular clouds with cosmic rays

Time-dependent escape of cosmic rays from supernova remnants, and their interaction with dense media

Molecular Environments of Supernova Remnants

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