TeV  -rays from old supernova remnants

Yamazaki, Ryo; Kohri, Kazunori; Bamba, Aya; Yoshida, Tatsuo; Tsuribe, Toru; Takahara, Fumio

doi:10.1111/j.1365-2966.2006.10832.x

Cited by 124 publications

(129 citation statements)

References 47 publications

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“…is the factor determined by the shock angle and the gyro-factor, and B d is the downstream magnetic field, which is expressed by B d = rB DC , where B DC is the magnetic field in the DC [14]. Since we consider an ionized DC, we ignore the ionneutral wave damping at the upstream of a shock (for particle acceleration in a radiative phase, see [16]).…”

Section: Supernova(e) In a Dense Cloudmentioning

confidence: 99%

“…The index is represented by s = (r + 2)/(r − 1), where r is the compression ratio of the shock [15], which is given by the Rankine-Hugoniot relation for t 1 < t age < t 2 , and r ∼ √ 2v s /v Au for t age > t 2 , where v Au is the upstream Alfvén velocity [14]. The maximum energy is determined by the age of SNR:…”

Section: Supernova(e) In a Dense Cloudmentioning

confidence: 99%

“…The evolution of a SNR and the particle acceleration around it is modeled following a previous study [14]. The shock velocity v s is written as a function of the SNR age (t age ) as…”

Section: Supernova(e) In a Dense Cloudmentioning

confidence: 99%

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Is the PAMELA anomaly caused by supernova explosions near the Earth?

et al. 2009

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We show that the anomaly of the positron fraction observed by the PAMELA experiment can be attributed to recent supernova explosion(s) in a dense gas cloud (DC) near the Earth. Protons are accelerated around the supernova remnant (SNR). Electrons and positrons are created through hadronic interactions inside the DC. Their spectrum is harder than that of the background because the SNR spends much time in a radiative phase. Our scenario predicts that the anti-proton flux dominates that of the background for 100 GeV. We compare the results with observations (Fermi, HESS, PPB-BETS, and ATIC).

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Section: Supernova(e) In a Dense Cloudmentioning

confidence: 99%

Section: Supernova(e) In a Dense Cloudmentioning

confidence: 99%

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Is the PAMELA anomaly caused by supernova explosions near the Earth?

et al. 2009

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“…The ratio of F γ (1−10 TeV)/F X (2−10 keV) has been suggested as a viable parameter for such a comparison (Yamazaki et al 2006). If the flux of the Chandra faint extended source (3) is adopted as an upper limit for any lowenergy counterpart and using the H.E.S.S.…”

Section: Searching For Counterpartsmentioning

confidence: 99%

Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622

Acero¹,

Aharonian²,

Akhperjanian³

et al. 2010

A&A

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Context. The detection of gamma-rays in the very-high-energy (VHE) range (100 GeV−100 TeV) offers the possibility of studying the parent population of ultrarelativistic particles found in astrophysical sources, so it is useful for understanding the underlying astrophysical processes in nonthermal sources. Aims. The discovery of the VHE gamma-ray source HESS J1507-622 is reported and possibilities regarding its nature are investigated. Methods. The H.E.S.S. array of imaging atmospheric Cherenkov telescopes (IACTs) has a high sensitivity compared with previous instruments (∼1% of the Crab flux in 25 h observation time for a 5σ point-source detection) and has a large field of view (∼5 • in diameter). HESS J1507-622 was discovered within the ongoing H.E.S.S. survey of the inner Galaxy, and the source was also studied by means of dedicated multiwavelength observations. Results. A Galactic gamma-ray source, HESS J1507-622, located ∼3.5 • from the Galactic plane was detected with a statistical significance >9σ. Its energy spectrum is well fitted by a power law with spectral index Γ = 2.24 ± 0.16 stat ± 0.20 sys and a flux above 1 TeV of (1.5 ± 0.4 stat ± 0.3 sys ) × 10 −12 cm −2 s −1 . Possible interpretations (considering both hadronic and leptonic models) of the VHE gamma-ray emission are discussed in the absence of an obvious counterpart.

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“…Green (2009) estimated an age of 30 000 years for the SNR and a distance of ∼10.5 kpc based on the proximity of the remnant with the HII region G35.5-0.0. As pointed out in several works (see Aharonian & Atoyan 1996;Yamazaki et al 2006;Gabici et al 2007Gabici et al , 2009, an SNR, in particular an old remnant (i.e. age larger than a few 10 000 years), interacting with a molecular cloud could explain the origin of the γ-ray emission via pion decay from protonproton collisions.…”

Section: Introductionmentioning

confidence: 99%

Identifying the counterpart of HESS J1858+020

Paron¹,

Giacani²

2010

A&A

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Aims. HESS J1858+020 is a weak γ-ray source that does not have any clear cataloged counterpart at any wavelengths. Recently, the source G35.6-0.4 was re-identified as a SNR. The HESS source lies towards the southern border of this remnant. The purpose of this work is to investigate the interstellar medium around the mentioned sources to look for possible counterparts of the very high energy emission. Methods. Using the 13 CO J = 1-0 line from the Galactic Ring Survey and mid-IR data from GLIMPSE we analyze the environs of HESS J1858+020 and SNR G35.6-0.4. Results. The 13 CO data show the presence of a molecular cloud towards the southern border of SNR G35.6-0.4 and at the same distance as the remnant. This cloud is composed of two molecular clumps, one over the SNR shell and the other located at the center of HESS J1858+020. We estimate a molecular mass and a density of ∼5 × 10 3 M and ∼500 cm −3 respectively for each clump. Considering the gamma-ray flux observed towards HESS J1858+020, we estimate that a molecular cloud with a density of at least 150 cm −3 could explain the very high energy emission hadronically. Thus, we suggest that the γ-ray emission detected in HESS J1858+020 is due to hadronic mechanism. Additionally, analyzing mid-IR emission, we find that the region is active in star formation, which could be considered as an alternative or complementary possibility to explain the very high energy emission.

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TeV -rays from old supernova remnants

Cited by 124 publications

References 47 publications

Is the PAMELA anomaly caused by supernova explosions near the Earth?

Is the PAMELA anomaly caused by supernova explosions near the Earth?

Discovery and follow-up studies of the extended, off-plane, VHE gamma-ray source HESS J1507-622

Identifying the counterpart of HESS J1858+020

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