The molecular clouds in the environs of the supernova remnants G349.7+0.2 and G18.8+0.3

Dubner, G.; Giacani, E.; Reynoso, E. M.; Paron, S.

doi:10.1051/0004-6361:20041327

Cited by 41 publications

(45 citation statements)

References 32 publications

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“…In Table 2, we report the physical parameters of the molecular clumps A and B. The obtained masses and densities are similar to those measured toward other MCs interacting with SNRs (see Paron et al 2012;Dubner et al 2004). Additionally, we calculated the total hydrogen column density N(H), which is an important parameter in the modeling of X-ray emission (see Sect.…”

Section: The Interstellar Medium Around G200-02supporting

confidence: 66%

An X-ray study of the supernova remnant G20.0-0.2 and its surroundings

Petriella

Paron

Giacani

2013

A&A

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Aims. We study the supernova remnant G20.0-0.2 and its surroundings to look for the high-energy counterpart of the radio nebula and to find evidence of interaction between the shock front and the interstellar medium. Methods. We used Chandra archival observations to analyze the X-ray emission from the supernova remnant. The surrounding gas was investigated using data extracted from the Galactic Ring Survey, the VLA Galactic Plane Survey, the Galactic Legacy Infrared Midplane Survey Extraordinaire, and the Bolocam Galactic Plane Survey. Results. G20.0-0.2 shows diffuse X-ray emission from the central region of the radio remnant. Although the current data do not allow us to distinguish between a thermal or non-thermal origin for the X-ray diffuse emission, based on the radio properties we suggest a synchrotron origin as the most favorable. The hard X-ray point source CXO J182807.4-113516 appears located at the geometrical center of the remnant and is a potential candidate to be the pulsar powering the nebula. We found a molecular cloud adjacent to the flattest border of G20.0-0.2, indicating a probable interaction between the shock front of the remnant and the molecular gas. Several young stellar object candidates are found located in the brightest region of the molecular emission, as well as over a millimeter continuum source and a dark cloud. This distribution is an indication of an active star-forming region around the supernova remnant.

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Section: The Interstellar Medium Around G200-02supporting

confidence: 66%

An X-ray study of the supernova remnant G20.0-0.2 and its surroundings

Petriella

Paron

Giacani

2013

A&A

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“…This parameter is a useful tool to trace shocked gas. Large values in the ratio R 2−1/1−0 are expected to be found in shocked molecular clouds, as observed in the clouds related with the SNRs G349.7+0.2 (R 2−1/1−0 ∼ 1.5; Dubner et al 2004), W44 (R 2−1/1−0 ∼ 1.3), IC443 (R 2−1/1−0 ∼ 1.3−4) and HB 21 (R 2−1/1−0 ∼ 1.6−2.3) (Seta et al 1998;Koo et al 2001). For the observed molecular clump we obtained R 2−1/1−0 ∼ 0.6, a low value that suggests that it is quiescent gas.…”

Section: Discussionmentioning

confidence: 72%

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

Paron

Dubner

Reynoso

et al. 2008

A&A

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Aims. This paper reports molecular observations towards the bright eastern knot (BEK) in the SNR Puppis A, a feature where radio and X-ray studies suggest that the shock front is interacting with a dense molecular clump. Methods. We performed high-resolution millimetric observations towards the BEK of Puppis A using the SEST telescope in the 12 CO J = 1-0 and 2-1 lines (beams of 45 and 23 , respectively). More extended, lower angular resolution 12 CO J = 1-0 observations taken from NANTEN archival data were also analyzed to obtain a complete picture. Results. In the velocity range near 16 km s −1 , which is the Puppis A systemic velocity, our study revealed two important properties: (i) no dense molecular gas is detected immediately adjacent to the eastern border of the BEK and (ii) the molecular clump detected very close to the radiocontinuum maximum is probably located in the foreground along the line of sight and has not yet been reached by the SNR shock front. We propose two possible scenarios for explaining the absence of molecular emission eastwards of the BEK border of Puppis A. Either the shock front has completely engulfed and destroyed a molecular clump or the shock front is interacting with part of a larger cloud, and we do not detect CO emission immediately beyond it because the molecules have been dissociated by photodissociation and by reactions with photoionized material due to the radiative precursor.

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“…The brightness enhancement seen towards the southwest of the SNR suggests that G349.7+0.2 is expanding into a density gradient caused by a HI cloud. Indeed, the coincidence of G349.7+0.2 with a dense MC (Dubner et al 2004) and the detection of five OH (1720 MHz) masers towards the centre of the SNR (Frail et al 1996) and of line emissions from several molecular transitions (Reynoso & Mangum 2000;Lazendic et al 2010) provide evidence in support of an interaction between the SNR and the MC. These masers and molecular line emissions are measured at similar velocities which, together with HI absorption measurements, originally placed the SNR at a distance of ∼22.4 kpc.…”

Section: Introductionmentioning

confidence: 88%

“…The energy spectrum of the VHE emission coincident with G349.7+0.2 is extracted above 220 GeV and fitted using the Declination ( Dubner et al (2004). The best fit position together with its 2σ CL contours of the TeV emission are marked with a magenta inverted triangle and magenta dashed contours, respectively.…”

Section: Hess Observationsmentioning

confidence: 99%

“…A postshock Hydrogen density of ∼ 7 cm −3 , leading to an ISM density of ∼1.7 cm −3 under the assumption of a strong shock was derived from the soft component of the SNR thermal X-ray spectrum (Lazendic et al 2005). From 12 CO observations, Dubner et al (2004) reported that G349.7+0.2 is associated with a MC, whose total mass and average density are estimated to be of M MC ∼ 5 × 10 3 M and n MC ∼ 2 × 10 4 cm −3 at 11.5 kpc, respectively. Another density estimate comes from the presence of 5 OH (1720 MHz) masers (Frail et al 1996) and strong H 2 lines (Hewitt et al 2009) towards the centre of the remnant, both tracers originating from shocked molecular region of very high density (n ∼ 10 4..6 cm −3 ).…”

Section: Multi-wavelength Considerationsmentioning

confidence: 99%

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H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

Abramowski¹,

Aharonian²,

Benkhali³

et al. 2015

A&A

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G349.7+0.2 is a young Galactic supernova remnant (SNR) located at the distance of 11.5 kpc and observed across the entire electromagnetic spectrum from radio to high energy (HE; 0.1 GeV < E < 100 GeV) γ-rays. Radio and infrared observations indicate that the remnant is interacting with a molecular cloud. In this paper, the detection of very high energy (VHE, E > 100 GeV) γ-ray emission coincident with this SNR with the High Energy Stereoscopic System (H.E.S.S.) is reported. This makes it one of the farthest Galactic SNR ever detected in this domain. An integral flux F(E > 400 GeV) = (6.5 ± 1.1 stat ± 1.3 syst ) × 10 −13 ph cm −2 s −1 corresponding to ∼0.7% of that of the Crab Nebula and to a luminosity of ∼10 34 erg s −1 above the same energy threshold, and a steep photon index Γ VHE = 2.8 ± 0.27 stat ± 0.20 syst are measured. The analysis of more than 5 yr of Fermi-LAT data towards this source shows a power-law like spectrum with a best-fit photon index Γ HE = 2.2 ±0.04 stat +0.13 −0.31 sys . The combined γ-ray spectrum of G349.7+0.2 can be described by either a broken power-law (BPL) or a power-law with exponential (or sub-exponential) cutoff (PLC). In the former case, the photon break energy is found at E br,γ = 55 +70 −30 GeV, slightly higher than what is usually observed in the HE/VHE γ-ray emitting middle-aged SNRs known to be interacting with molecular clouds. In the latter case, the exponential (respectively sub-exponential) cutoff energy is measured at E cut,γ = 1.4 +1.6 −0.55 (respectively 0.35 +0.75 −0.21 ) TeV. A pion-decay process resulting from the interaction of the accelerated protons and nuclei with the dense surrounding medium is clearly the preferred scenario to explain the γ-ray emission. The BPL with a spectral steepening of 0.5−1 and the PLC provide equally good fits to the data. The product of the average gas density and the total energy content of accelerated protons and nuclei amounts to n H W p ∼ 5 × 10 51 erg cm −3 .

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The molecular clouds in the environs of the supernova remnants G349.7+0.2 and G18.8+0.3

Cited by 41 publications

References 32 publications

An X-ray study of the supernova remnant G20.0-0.2 and its surroundings

An X-ray study of the supernova remnant G20.0-0.2 and its surroundings

High-resolution CO observations towards the bright eastern knot of the SNR Puppis A

H.E.S.S. detection of TeV emission from the interaction region between the supernova remnant G349.7+0.2 and a molecular cloud

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