The radio spectral index of the Vela supernova remnant

Álvarez, H.; Aparici, J.; May, J.; Reich, P.

doi:10.1051/0004-6361:20010509

Cited by 57 publications

(86 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Subsequent observations at 29.9, 34.5, and 408 MHz revealed one more region of intensified emission Vela W, which features two peaks and is weaker than Vela Y and Vela Z (Alvarez et al 2001). The spectral shape of the Vela W radio emission is similar to the spectral shape of the radio emission from Vela Y and Vela Z which suggests the same nature of these localised emission regions (Alvarez et al 2001).…”

Section: Introductionmentioning

confidence: 93%

See 1 more Smart Citation

Modelling of the radio emission from the Vela supernova remnant

Sushch

Hnatyk

2014

A&A

View full text Add to dashboard Cite

Supernova remnants (SNRs) are widely considered to be sites of Galactic cosmic ray (CR) acceleration. Vela is one of the Galactic composite SNRs closest to Earth accompanied by the Vela pulsar and its pulsar wind nebula (PWN) Vela X. The Vela SNR is one of the most studied remnants and it benefits from precise estimates of various physical parameters such as distance and age. Therefore, it is a perfect object for a detailed study of physical processes in SNRs. The Vela SNR expands into the highly inhomogeneous cloudy interstellar medium (ISM) and its dynamics are determined by the heating and evaporation of ISM clouds. It features an asymmetrical X-ray morphology, which is explained by the expansion into two media with different densities. This could occur if the progenitor of the Vela SNR exploded close to the edge of the stellar wind bubble of the nearby Wolf-Rayet star γ 2 Velorum causing one part of the remnant to expand into the bubble. The interaction of the ejecta and the main shock of the remnant with ISM clouds causes formation of secondary shocks at which additional particle acceleration takes place. This may lead to the almost uniform distribution of relativistic particles inside the remnant. We calculate the synchrotron radio emission within the framework of the new hydrodynamical model that assumes the supernova explosion at the edge of the stellar wind bubble. The simulated radio emission agrees well with both the total radio flux from the remnant and the complicated radio morphology of the source.

show abstract

Section: Introductionmentioning

confidence: 93%

“…The nucleon number densities n, corresponding filling factors f , and the kinetic gas temperatures T are presented for both hot and cool components of the remnant's interior. The simulated radio emission from the remnant is compared to the observational data presented in Alvarez et al (2001).…”

Section: Introductionmentioning

confidence: 99%

Modelling of the radio emission from the Vela supernova remnant

Sushch

Hnatyk

2014

A&A

View full text Add to dashboard Cite

show abstract

“…High frequency studies show a spectral break for the southern lobe that would suggest a life time of 3 × 10 7 yrs (see Hardcastle et al 2009). Furthermore, no spectral break is observed in the northern lobe (both the giant and the middle lobe), suggesting that they have very recently undergone some particle injection event (Alvarez et al 2000;Hardcastle et al 2009, and refs. therein).…”

Section: Merger and Different Phases Of Radio Activitymentioning

confidence: 98%

Centaurus A: morphology and kinematics of the atomic hydrogen

Struve

Oosterloo

Morganti

et al. 2010

A&A

View full text Add to dashboard Cite

We present new ATCA 21-cm line observations of the neutral hydrogen in the nearby radio galaxy Centaurus A. We image in detail (with a resolution down to 7 , ∼100 pc) the distribution of H i along the dust lane. Our data have better velocity resolution and better sensitivity than previous observations. The H i extends for a total of ∼15 kpc. The data, combined with a titled-ring model of the disk, allow to conclude that the kinematics of the H i is that of a regularly rotating, highly warped structure down to the nuclear scale.The parameters (in particular the inclination) of our model are somewhat different from some of the previously proposed models but consistent with what was recently derived from stellar light in a central ring. The model nicely describes also the morphology of the dust lane as observed with Spitzer. There are no indications that large-scale anomalies in the kinematics exist that could be related to supplying material for the AGN. Large-scale radial motions do exist, but these are only present at larger radii (r > 6 kpc). This unsettled gas is mainly part of a tail/arm like structure. The relatively regular kinematics of the gas in this structure suggests that it is in the process of settling down into the main disk. The presence of this structure further supports the merger/interaction origin of the H i in Cen A. From the structure and kinematics we estimate a timescale of 1.6−3.2 × 10 8 yr since the merging event. No bar structure is needed to describe the kinematics of the H i. The comparison of the timescale derived from the large-scale H i structure and those of the radio structure together with the relative regularity of the H i down to the sub-kpc regions does not suggest a oneto-one correspondence between the merger and the phase of radio activity. Interestingly, the radial motions of the outer regions are such that the projected velocities are redshifted compared to the regular orbits. This means that the blueshifted absorption discovered earlier and discussed in our previous paper cannot be caused by out-moving gas at large radius projected onto the centre. Therefore, the interpretation of the blueshifted absorption, together with at least a fraction of the redshifted nuclear absorption, as evidence for a regular inner disk, still holds. Finally, we also report the discovery of two unresolved clouds detected at 5.2 and 11 kpc away (in projection) from the H i disk. They are likely an other example of a left-over of the merger that brought the H i gas.

show abstract

“…Rishbeth (1958) already presumed that Vela X stands out in comparison to the other two objects (Vela Y, Vela Z), as its radio spectrum tends to be flatter. A review of radio observations of the region was given by Alvarez et al (2001). The size of the Vela X radio emission is coarsely given as 3…”

Section: Introductionmentioning

confidence: 99%

Probing the extent of the non-thermal emission from the Vela X region at TeV energies with H.E.S.S.

Abramowski

Acero

Aharonian

et al. 2012

A&A

View full text Add to dashboard Cite

Context. Vela X is a region of extended radio emission in the western part of the Vela constellation: one of the nearest pulsar wind nebulae, and associated with the energetic Vela pulsar . Extended very-high-energy (VHE) γ-ray emission (HESS J0835−455) was discovered using the H.E.S.S. experiment in 2004. The VHE γ-ray emission was found to be coincident with a region of X-ray emission discovered with ROSAT above 1.5 keV (the so-called Vela X cocoon): a filamentary structure extending southwest from the pulsar to the centre of Vela X. Aims. A deeper observation of the entire Vela X nebula region, also including larger offsets from the cocoon, has been performed with H.E.S.S. This re-observation was carried out in order to probe the extent of the non-thermal emission from the Vela X region at TeV energies and to investigate its spectral properties. Methods. To increase the sensitivity to the faint γ-ray emission from the very extended Vela X region, a multivariate analysis method combining three complementary reconstruction techniques of Cherenkov-shower images is applied for the selection of γ-ray events. The analysis is performed with the On/Off background method, which estimates the background from separate observations pointing away from Vela X; towards regions free of γ-ray sources but with comparable observation conditions. Results. The γ-ray surface brightness over the large Vela X region reveals that the detection of non-thermal VHE γ-ray emission from the PWN HESS J0835−455 is statistically significant over a region of radius 1.2• around the position α = 08 h 35 m 00 s , δ = −45• 36 00 (J2000). The Vela X region exhibits almost uniform γ-ray spectra over its full extent: the differential energy spectrum can be described by a power-law function with a hard spectral index Γ = 1.32 ± 0.06 stat ± 0.12 sys and an exponential cutoff at an energy of (14.0 ± 1.6 stat ± 2.6 sys ) TeV. Compared to the previous H.E.S.S. observations of Vela X the new analysis confirms the general spatial overlap of the bulk of the VHE γ-ray emission with the X-ray cocoon, while its extent and morphology appear more consistent with the (more extended) radio emission, contradicting the simple correspondence between VHE γ-ray and X-ray emissions. Morphological and spectral results challenge the interpretation of the origin of γ-ray emission in the GeV and TeV ranges in the framework of current models. Key words. radiation mechanisms: non-thermal -ISM: individual objects: Vela X -ISM: individual objects: HESS J0835-455 -gamma rays: general Article published by EDP Sciences A38, page 1 of 11 A&A 548, A38 (2012)

show abstract

The radio spectral index of the Vela supernova remnant

Cited by 57 publications

References 20 publications

Modelling of the radio emission from the Vela supernova remnant

Modelling of the radio emission from the Vela supernova remnant

Centaurus A: morphology and kinematics of the atomic hydrogen

Probing the extent of the non-thermal emission from the Vela X region at TeV energies with H.E.S.S.

Contact Info

Product

Resources

About