AMI observations of northern supernova remnants at 14-18 GHz

Hurley‐Walker, N.; Scaife, Anna M. M.; Green, David A.; Davies, Matthew; Grainge, Keith; Hobson, M.; Jones, Michael E.; Kaneko, T.; Lasenby, A.; Pooley, G. G.; Saunders, Richard D. E.; Scott, Paul F.; Titterington, D.; Waldram, Elizabeth; Zwart, Jonathan T. L.

doi:10.1111/j.1365-2966.2009.14583.x

Cited by 31 publications

(14 citation statements)

References 45 publications

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“…-G57.2+0.8 (4C 21.53). The derived value α = −0.62±0.01 is slightly larger than the value of α = −0.67 by Hurley-Walker et al (2009), which could be ascribed to a higher λ6 cm flux density. -G59.8+1.2.…”

Section: Snr Spectramentioning

confidence: 59%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Sun

Reich

et al. 2011

A&A

119

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Aims. We study the spectral and polarization properties of supernova remnants (SNRs) using our λ6 cm survey data. Methods. We analyse data from observations taken as part of the Sino-German λ6 cm polarization survey of the Galactic plane. By using the integrated flux densities at λ6 cm together with measurements at other wavelengths from the literature, we derive the global spectra of 50 SNRs. In addition, from the observations at λ6 cm we obtain the polarization images of 24 SNRs. Results. We derive integrated flux densities at λ6 cm for 51 small SNRs with angular sizes smaller than 1 • . We are able to derive global radio spectral indices in all the cases except for Cas A. For the SNRs G15.1−1.6, G16.2−2.7, G16.4−0.5, G17.4−2.3, G17.8−2.6, G20.4+0.1, G36.6+2.6, G43.9+1.6, G53.6−2.2, G55.7+3.4, G59.8+1.2, G68.6−1.2, and G113.0+0.2, the spectra have been significantly improved. From our analysis, we argue that the object G16.8−1.1 is probably an H ii region instead of a SNR. Cas A shows a secular decrease in total intensity, and we measure a flux density of 688 ± 35 Jy at λ6 cm between 2004 and 2008. We detect polarized emission from 25 SNRs. For G16.2−2.7, G69.7+1.0, G84.2−0.8, and G85.9−0.6, the polarized emission is detected for the first time confirming that they are SNRs. Conclusions. High-frequency observations of SNRs are difficult but essential to determine their spectra and measure their polarization in particular towards the inner Galaxy, where Faraday effects are important.

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Section: Snr Spectramentioning

confidence: 59%

A Sino-Germanλ6 cm polarization survey of the Galactic plane

Sun

Reich

et al. 2011

A&A

119

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“…Therefore this can only be considered a lower limit. Hurley-Walker et al (2009) explain the apparent lower flux values in the AMI measurments by missing short spacings. It may also be that the full extent of the source was underestimated, because only the shell part is an obvious feature in the old observations.…”

Section: Radio Continuum Emissionmentioning

confidence: 87%

“…The radio continuum spectrum of G57.2+0.8 is displayed in Figure 3. The ra-dio spectral index α is either −0.55 ± 0.02 or −0.65 ± 0.03, depending on whether we include the AMI high frequency measurements (Hurley-Walker et al 2009) and the Effelsberg 10.7 GHz observation by Sieber & Seiradakis (1984). The Sieber & Seiradakis (1984) 10.7 GHz image does not cover the entire SNR, only the bright shell.…”

Section: Radio Continuum Emissionmentioning

confidence: 99%

A Radio Continuum and Polarization Study of SNR G57.2+0.8 Associated with Magnetar SGR 1935+2154

Kothes

Sun

Gaensler

et al. 2018

ApJ

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We present a radio continuum and linear polarization study of the Galactic supernova remnant G57.2+0.8, which may host the recently discovered magnetar SGR 1935+2154. The radio SNR shows the typical radio continuum spectrum of a mature supernova remnant with a spectral index of α = −0.55 ± 0.02 and moderate polarized intensity. Magnetic field vectors indicate a tangential magnetic field, expected for an evolved SNR, in one part of the SNR and a radial magnetic field in the other. The latter can be explained by an overlapping arc-like feature, perhaps a pulsar wind nebula, emanating from the magnetar. The presence of a pulsar wind nebula is supported by the low average braking index of 1.2, we extrapolated for the magnetar, and the detection of diffuse X-ray emission around it. We found a distance of 12.5 kpc for the SNR, which identifies G57.2+0.8 as a resident of the Outer spiral arm of the Milky Way. The SNR has a radius of about 20 pc and could be as old as 41,000 years. The SNR has already entered the radiative or pressure-driven snowplow phase of its evolution. We compared independently determined characteristics like age and distance for both, the SNR and SGR 1935+2154, and conclude that they are physically related.

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“…The SA was built first. Partly to test it while the LA was being completed, we used the SA to observe Galactic supernova remnants and likely regions of spinning dust (AMI Consortium: Scaife et al 2008, 2009a,b; AMI Consortium: Hurley‐Walker et al 2009a,b) bright enough not to need source subtraction. However, we also wanted to begin SZ observation, test our algorithms to extract SZ signals in the presence of radio sources, CMB primary anisotropies and receiver noise, and begin our SZ science programme.…”

Section: Introductionmentioning

confidence: 99%

Sunyaev-Zel’dovich observations of galaxy clusters out to the virial radius with the Arcminute Microkelvin Imager★

Zwart¹,

Feroz²,

Davies³

et al. 2011

Monthly Notices of the Royal Astronomical Society

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We present observations using the Small Array of the Arcminute Microkelvin Imager (AMI; 14–18 GHz) of four Abell and three MACS clusters spanning 0.171–0.686 in redshift. We detect Sunyaev–Zel’dovich (SZ) signals in five of these without any attempt at source subtraction, although strong source contamination is present. With radio‐source measurements from high‐resolution observations, and under the assumptions of spherical β‐model, isothermality and hydrostatic equilibrium, a Bayesian analysis of the data in the visibility plane detects extended SZ decrements in all seven clusters over and above receiver noise, radio sources and primary cosmic microwave background imprints. Formal Bayesian evidence ratios range from 1011:1 to 1043:1 for six of the clusters and 3000:1 for one with substantially fewer data than the others. We present posterior probability distributions for, e.g., total mass and gas fraction averaged over radii internal to which the mean overdensity is 1000, 500 and 200, r200 being the virial radius. Reaching r200 involves some extrapolation for the nearer clusters but not for the more distant ones. We find that our estimates of gas fraction are low (compared with most in the literature) and decrease with increasing radius. These results appear to be consistent with the notion that gas temperature in fact falls with distance (away from near the cluster centre) out to the virial radius.

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AMI observations of northern supernova remnants at 14-18 GHz

Cited by 31 publications

References 45 publications

A Sino-Germanλ6 cm polarization survey of the Galactic plane

A Sino-Germanλ6 cm polarization survey of the Galactic plane

A Radio Continuum and Polarization Study of SNR G57.2+0.8 Associated with Magnetar SGR 1935+2154

Sunyaev-Zel’dovich observations of galaxy clusters out to the virial radius with the Arcminute Microkelvin Imager★

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