Radio observations of interstellar bubbles surrounding massive stars

Cappa, C. E.; Arnal, E. M.; Cichowolski, Silvina; Goss, W. M.; Pineault, S.

doi:10.1017/s0074180900212977

Cited by 20 publications

(21 citation statements)

References 25 publications

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“…The CC-SNR, on the other hand, by design, expands in a wind of much lower density, followed by a constantdensity shocked-wind zone, and therefore remains in the ejectadominated stage until the end of the simulation. At the edge of the constant-density zone, we assume the presence of a cold, thin (0.5 pc) dense shell of swept-up material, similar to those known to exist around WR stars (Cappa et al 2003). After 2000 years, the forward shock of this Type-Ic SNR has expanded out to a radius of about 14 pc.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…According to evolutionary models of interstellar bubbles, the expected energy conversion efficiency = E kin /E w is on the order of 0.2 or less (McCray 1983). Observationally, the values of derived from optical and radio observations can be as low as 0.02 (Cappa et al 2003), indicating that there are cases where severe energetic losses may occur.…”

Section: The Action Of the Dwcl Source Candidatesmentioning

confidence: 99%

“…The situation with respect to radio observations, reviewed by Cappa et al (2003), has evolved considerably with the advent of large Galactic neutral hydrogen (H i) surveys, namely the Canadian Galactic Plane Survey (CGPS; Taylor et al 2003), the Southern GPS (SGPS; McClure-Griffiths et al 2005;Haverkorn et al 2006) and the VLA (VGPS; Stil et al 2006). These surveys at ∼1 arcmin resolution have made it possible to identify and study the structure and dynamics of many neutral H i shells (McClure-Griffiths et al 2000;Uyaniker & Kothes 2002;Stil & Irwin 2001;Stil et al 2004).…”

Section: Introductionmentioning

confidence: 99%

“…These surveys at ∼1 arcmin resolution have made it possible to identify and study the structure and dynamics of many neutral H i shells (McClure-Griffiths et al 2000;Uyaniker & Kothes 2002;Stil & Irwin 2001;Stil et al 2004). Interestingly enough, the large majority of shells detected by their neutral hydrogen emission have low inferred expansion velocities, typically less than or on the order of 10 km s −1 (Cappa et al 2003).…”

Section: Introductionmentioning

confidence: 99%

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GSH 91.5+2–114: A large H i shell in the outer part of the Galaxy

Cichowolski

Pineault

2010

A&A

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GSH 91.5 + 2 − 114 is a large H i shell located in the outer Galaxy at a kinematic distance of about 15 kpc. It was first identified in the Canadian Galactic Plane Survey (CGPS) by Pineault et al. (2002, ASP Conf. Ser., 276, 332) as being possibly associated with objects possessing infrared colors, which indicates strong stellar winds. The H i shell has no obvious continuum counterpart in the CGPS radio images at 408 and 1420 MHz or in the IRAS images. We found no evidence for early-type massive stars, most likely as a result of the large extinction that is expected for this large distance. An analysis of the energetics and of the main physical parameters of the H i shell shows that this shell is likely the result of the combined action of the stellar winds and supernova explosions of many stars. We investigate whether a number of slightly extended regions characterized by a thermal radio continuum and located near the periphery of the H i shell could be the result of star formation triggered by the expanding shell.

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“…The situation for radio observations, reviewed by Cappa et al (2003), has now evolved considerably with the advent of large galactic surveys, namely the Canadian Galactic Plane Survey (CGPS, Taylor et al 2003), the Southern GPS (SGPS, McClureGriffiths et al 2005;Haverkorn et al 2006), and the VLA GPS A&A 532, A9 (2011) (VGPS, Stil et al 2006). These surveys now make it possible to identify and study the structure and dynamics of the ISM at ∼1 arcmin resolution.…”

Section: Introductionmentioning

confidence: 99%

The structure and kinematics of the ISM around HD 192281

Arnal

Cichowolski

Pineault

et al. 2011

A&A

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Aims. This work aims at investigating the interaction of HD 192281 (O5 Vn((f))p) with its local ISM. The purpose is to analyse the effects that a massive star has on the structure and kinematics of its surrounding gas. Methods. To carry out this study, we used high-resolution radio continuum and 21-cm H i line data from the Canadian Galactic Plane Survey (CGPS). This data base was complemented with radio continuum, infrared, and molecular data retrieved from available surveys. Given that HD 192281 is very likely a runaway star, we attempt to establish whether the observed H i distribution can be interpreted in terms of a simple bow shock model. Results. Analysis of the H i data shows the presence of an H i feature likely to be associated with HD 192281. This feature remains detectable from ∼5 to -10 km s −1 . At the most negative radial velocities, the shape of the H i feature is highly reminiscent of a bow shock structure seen projected onto the plane of the sky. This feature has counterparts at radio-continuum, infrared, and CO emissions. The analysis of the radio continuum data suggests a thermal spectrum for the gas related to this structure.

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Radio observations of interstellar bubbles surrounding massive stars

Cited by 20 publications

References 25 publications

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

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

GSH 91.5+2–114: A large H i shell in the outer part of the Galaxy

The structure and kinematics of the ISM around HD 192281

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