Radio spectral index variations of the SNR HB3

Tian, Wenwu; Leahy, D. A.

doi:10.1051/0004-6361:20042431

Cited by 32 publications

(42 citation statements)

References 13 publications

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“…They derived a spectral index for HB3 of α = −0.34 ± 0.25 between these two frequencies (Tian & Leahy 2005. This result was confirmed by the TT-plot method.…”

Section: Introductionsupporting

confidence: 63%

The radio spectrum and magnetic field structure of SNR HB3

Shi

Han

Gao

et al. 2008

A&A

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Context. Evidence for a spectral flattening of the supernova remnant (SNR) HB3 (G132.7+1.3) was recently claimed in the literature based on previously published total flux density data, and the flattening was further interpreted as the discovery of thermal bremsstrahlung emission in the shell of HB3. Aims. A spectral flattening has never been observed from any SNR before. Reliable observations of HB3 at frequencies above 3000 MHz are crucial to confirm such a spectral behaviour. Methods. We extracted 4800 MHz total intensity and polarisation data of HB3 from the Sino-German 6 cm polarisation survey of the Galactic plane made with the Urumqi 25 m telescope, and analysed the spectrum of HB3, together with Effelsberg data at 1408 MHz and 2675 MHz. Results. We found an overall spectral index of HB3 of α = −0.61 ± 0.06 between 1408 MHz and 4800 MHz, similar to the index at lower frequencies. There is no spectral flattening at high frequencies. We detected strong polarised emission from HB3 at 4800 MHz. Our 4800 MHz data show a tangential field orientation in the HB3 shell.

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“…They derived a spectral index for HB3 of α = −0.34 ± 0.25 between these two frequencies (Tian & Leahy 2005. This result was confirmed by the TT-plot method.…”

Section: Introductionsupporting

confidence: 63%

The radio spectrum and magnetic field structure of SNR HB3

Shi

Han

Gao

et al. 2008

A&A

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“…2), and then determining spectra by employing the special T-T plot spectral analysis method of Leahy (2006). The T-T plot method is described more generally in the paper of Tian & Leahy (2005). For the T-T plot spectral index analysis, we select a single region covering the whole G108.2−0.6 shown in Fig.…”

Section: Flux Density and Spectral Indexmentioning

confidence: 99%

Discovery of a new faint radio SNR G108.2-0.6

Leahy

Foster

2007

A&A

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A new faint and large shell-type radio Supernova Remnant (SNR) G108.2−0.6 has been discovered in the Canadian Galactic Plane Survey (CGPS). The SNR shows an elliptical shell-type structure at 1420 MHz, and has a 408-1420 MHz TT-plot spectral index of α = −0.5 ± 0.1 (S ν ∝ν α ), typical of a shell-type SNR. The remnant's flux density at 1420 MHz is 6.6 ± 0.7 Jy, and at 408 MHz is 11.5 ± 1.2 Jy. Both of these are corrected for compact sources. An integrated spectral index of −0.45 ± 0.13 is determined. This new SNR has among the lowest surface brightness of any known remnants (Σ 1 GHz = 2.4 × 10 −22 W m −2 Hz −1 sr −1 ). 21 cm Stokes Q and U CGPS data (plus preliminary Effelsberg Q and U maps) show some suggestive features that correlate with total power. H i observations show structures associated with G108.2−0.6 in the radial velocity range −53 to −58 km s −1 , and indicate it is located in the Perseus arm shock at a distance of 3.2 ± 0.6 kpc. At this distance the diameter of G108.2−0.6 is 58 pc. IRAS maps (12, 25, 60 and 100 µm) of the new SNR show rich infrared emission surrounding G108.2−0.6.

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“…For compact sources, the flux density's errors are taken as the formal Gaussian fit errors. The influence of compact sources within the SNR is much reduced by employing similar methods to Tian & Leahy (2005).…”

Section: Observations and Analysismentioning

confidence: 99%

The radio SNR G65.1+0.6 and its associated pulsar J1957+2831

Leahy

2006

A&A

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New images of the radio Supernova Remnant (SNR) G65.1+0.6 are presented, based on the 408 MHz and 1420 MHz continuum emission and the HI-line emission data of the Canadian Galactic Plane Survey (CGPS). A large shell-like structure seen in the 2695 MHz Effelsberg map appears to have nonthermal spectral index. HI observations show structures associated with the SNR G65.1+0.6 in the radial velocity range of −20 to −26 km s −1 and suggest a distance of 9.2 kpc for the SNR. The estimated Sedov age for G65.1+0.6 is 4−14 × 10 4 yr. The pulsar (PSR) J1957+2831 is possibly associated with G65.1+0.6, with consistent distance and kinematic age estimate, but different characteristic age than the SNR. The EGRET source 3EG J1958+2909 and γ-ray source 2CG 065+00 are also near the eastern edge of the SNR but do not agree in position with the pulsar and are likely not associated with the SNR. The SNR's flux densities at 408 MHz (8.6 ± 0.8 Jy), 1420 MHz (4.9 ± 0.5 Jy) and 2695 MHz (3.3 ± 0.5 Jy) have been corrected for flux densities from compact sources within the SNR. The integrated flux density based spectral index (S ν ∝ ν −α ) between 1420 MHz and 408 MHz is 0.45 ± 0.11 and agrees with the T-T plot spectral index of 0.34 ± 0.20. The nearby SNR DA495 has a T-T plot spectral index of 0.50 ± 0.01.

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Radio spectral index variations of the SNR HB3

Cited by 32 publications

References 13 publications

The radio spectrum and magnetic field structure of SNR HB3

The radio spectrum and magnetic field structure of SNR HB3

Discovery of a new faint radio SNR G108.2-0.6

The radio SNR G65.1+0.6 and its associated pulsar J1957+2831

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