scholarly journals A Nonthermal Superbubble in the Irregular Galaxy IC 10

1988 ◽  
Vol 101 ◽  
pp. 465-467
Author(s):  
Evan D. Skillman
Keyword(s):  
High Resolution ◽  
Spectral Index ◽  
Supernova Remnant ◽  
Radio Continuum ◽  
Irregular Galaxy ◽  
Large Size ◽  
Ic 10

AbstractNew high resolution radio continuum images of the nearby irregular galaxy IC 10 have revealed a large (> 250 pc) nonthermal source. The source is roughly circular with a spectral index of ∼ –0.5, and is most likely a very large supernova remnant. Its large size suggests that it is the result of several supernovae, and may be related to the supershells observed in our own and other galaxies.

scholarly journals A High-Resolution Radio Continuum Study Of The Dwarf Irregular Galaxy IC 10

2017 ◽  
pp. stx188 ◽  
Author(s):  
J. Westcott ◽  
E. Brinks ◽  
R.J. Beswick ◽  
V. Heesen ◽  
M.K. Argo ◽  
...  
Keyword(s):  
High Resolution ◽  
Radio Continuum ◽  
Irregular Galaxy ◽  
Ic 10

scholarly journals A radiocontinuum study of the supernova remnant MSH 11-61A

2005 ◽  
pp. 47-56 ◽  
Author(s):  
M.D. Filipovic ◽  
J.L. Payne ◽  
P.A. Jones
Keyword(s):  
High Resolution ◽  
Flux Density ◽  
Spectral Index ◽  
Supernova Remnant ◽  
Radio Continuum ◽  
Density Measurements ◽  
X Ray ◽  
Moderate Resolution ◽  
Turn Over

We present a high-resolution radio-continuum study of Galactic supernova remnant MSH11-61A. We combine moderate resolution X-ray, radio-continuum and CO data to study the morphology and kinematics of MSH 11-61A. We estimate the radio-continuum spectral index to be ?843?4850=- 0.33?0.07 based on our flux density measurements and also note that this SNR has significant 'turn?over' spectra at lower (29.9843 MHz) frequencies. The diameter of MSH1161A is estimated to be 12.5' with 'ear' extensions of 41 to the northwest and southeast. The striking anticorrelation between X-ray and radio-continuum images confirms a mixed-morphology classification of this remnant. The CO images are consistent with a distance reported by Rosado et al.(1996) of about 7 kpc. .

scholarly journals Low frequency (74 MHz) radio continuum observations of the inner 13° × 7° of the Galactic center

2013 ◽  
Vol 9 (S303) ◽  
pp. 464-466
Author(s):  
M. Rickert ◽  
F. Yusef-Zadeh ◽  
C. Brogan
Keyword(s):  
High Resolution ◽  
Molecular Cloud ◽  
Supernova Remnant ◽  
Galactic Center ◽  
Low Frequency ◽  
Radio Continuum ◽  
Large Array ◽  
Very Large Array ◽  
Image Displays ◽  
Western Side

AbstractWe analyze a high resolution (114″ × 60″) 74 MHz image of the Galactic center taken with the Very Large Array (VLA). We have identified several absorption and emission features in this region, and we discuss preliminary results of two Galactic center sources: the Sgr D complex (G1.1–0.1) and the Galactic center lobe (GCL).The 74 MHz image displays the thermal and nonthermal components of Sgr D and we argue the Sgr D supernova remnant (SNR) is consistent with an interaction with a nearby molecular cloud and the location of the Sgr D Hii region on the near side of the Galactic center. The image also suggests that the emission from the eastern side of the GCL contains a mixture of both thermal and nonthermal sources, whereas the western side is primarily thermal.

scholarly journals Multifrequency radio observations of a SNR in the LMC: The case of SNR J0527-6549 (DEM l204)

2010 ◽  
pp. 43-49 ◽  
Author(s):  
L.M. Bozzetto ◽  
M.D. Filipovic ◽  
E.J. Crawford ◽  
I.S. Bojicic ◽  
J.L. Payne ◽  
...  
Keyword(s):  
Spectral Index ◽  
Supernova Remnant ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
High Order ◽  
Older Age ◽  
Radio Observations ◽  
Large Size ◽  
Peak Value ◽  
Compact Array

We present a detailed study and results of new Australia Telescope Compact Array (ATCA) observations of supernova remnant SNR J0527-6549. This Large Magellanic Cloud (LMC) object follows a typical supernova remnant (SNR) horseshoe morphology with a diameter of D=(66?58)?1 pc which is among the largest SNRs in the LMC. Its relatively large size indicates older age while a steeper than expected radio spectral index of ?=-0.92?0.11 is more typical of younger and energetic SNRs. Also, we report detections of regions with a high order of polarization at a peak value of ~54%?17% at 6 cm.

scholarly journals Radio Emission from the Supernova Remnant Vela-X

1968 ◽  
Vol 21 (2) ◽  
pp. 201 ◽  
Author(s):  
DK Milne
Keyword(s):  
Magnetic Field ◽  
High Resolution ◽  
Radio Emission ◽  
Spectral Index ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Magnetic Field Direction ◽  
Radio Observations ◽  
Optical Identification ◽  
Polarization Measurements

Radio observations are presented of the fairly large galactic complex Vela-X, Y, and Z. These sources are believed to be the remnant of a supernova having an optical identification with the filamentary nebula Stromlo 16. The brightness distributions, obtained at four frequencies, indicate an open annular structure reminiscent of other supernova remnants. The variation of spectral index over the region is investigated and shows that the radiation is substantially nontherm81, the integrated fluxes yielding a spectral index of -0,3. A high resolution distribution of magnetic field direction is deduced from polarization measurements made at three frequencies; a circumferential magnetic field is a possible interpretation of the field orientations.

scholarly journals Radio observations of supernova remnant G1.9+0.3

2019 ◽  
Vol 492 (2) ◽  
pp. 2606-2621 ◽  
Author(s):  
Kieran J Luken ◽  
Miroslav D Filipović ◽  
Nigel I Maxted ◽  
Roland Kothes ◽  
Ray P Norris ◽  
...  
Keyword(s):  
Spectral Index ◽  
Supernova Remnant ◽  
Radio Spectrum ◽  
Northern Region ◽  
Radio Continuum ◽  
Expansion Rate ◽  
Continuum Emission ◽  
Rotation Measure ◽  
Cas A ◽  
Recent Epoch

ABSTRACT We present 1–10 GHz radio continuum flux density, spectral index, polarization, and rotation measure (RM) images of the youngest known Galactic supernova remnant (SNR) G1.9+0.3, using observations from the Australia Telescope Compact Array. We have conducted an expansion study spanning eight epochs between 1984 and 2017, yielding results consistent with previous expansion studies of G1.9+0.3. We find a mean radio continuum expansion rate of (0.78 ± 0.09) per cent yr−1 (or ∼8900 km s−1 at an assumed distance of 8.5 kpc), although the expansion rate varies across the SNR perimetre. In the case of the most recent epoch between 2016 and 2017, we observe faster-than-expected expansion of the northern region. We find a global spectral index for G1.9+0.3 of −0.81 ± 0.02 (76 MHz–10 GHz). Towards the northern region, however, the radio spectrum is observed to steepen significantly (∼−1). Towards the two so-called (east and west) ‘ears’ of G1.9+0.3, we find very different RM values of 400–600 and 100–200 rad m2, respectively. The fractional polarization of the radio continuum emission reaches (19 ± 2) per cent, consistent with other, slightly older, SNRs such as Cas A.

scholarly journals Aperture Synthesis Observations of the Supernova Remnant G73.9+0.9

1988 ◽  
Vol 101 ◽  
pp. 297-300
Author(s):  
P. Chastenay ◽  
S. Pineault
Keyword(s):  
Spectral Index ◽  
Supernova Remnant ◽  
Aperture Synthesis ◽  
Radio Continuum ◽  
General Morphology ◽  
Spatially Resolved ◽  
A Value ◽  
Shell Type

AbstractRadio continuum observations, obtained with the DRAO Synthesis Telescope, are presented of the new supernova remnant (SNR) G73.9+0.9. Our map at 1420 MHz shows indications of spatially resolved knots of emission in the brightest part of the remnant. The 408 MHz map, although of lower resolution, shows the same general morphology. The spectral index α (Sv∝v−α) between 1420 and 408 MHz is about 0.5, a value typical for shell type SNRs. The morphology however is more suggestive of a filled centre SNR.

scholarly journals 20 cm VLA radio-continuum study of M31-images and point source catalogues DR2: Extraction of a supernova remnant sample

2014 ◽  
pp. 15-24 ◽  
Author(s):  
T.J. Galvin ◽  
M.D. Filipovic
Keyword(s):  
Point Source ◽  
Spectral Index ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Small Population ◽  
Radio Continuum ◽  
X Ray ◽  
Search Area ◽  
Frequency Domains ◽  
Discrete Radio Sources

We present Data Release 2 of the Point Source Catalogue created from a series of previously constructed radio-continuum images of M31 at ?=20 cm (v=1.4 GHz) from archived VLA observations. In total, we identify a collection of 916 unique discrete radio sources across the field of M31. Comparing these detected sources to those listed by Gelfand et al. (2004) at ?=92 cm, the spectral index of 98 sources has been derived. The majority (73%) of these sources exhibit a spectral index of ?<-0.6, indicating that their emission is predominantly non-thermal in nature, which is typical for background objects and Supernova Remnants (SNRs). Additionally, we investigate the presence of radio counterparts for some 156 SNRs and SNR candidates, finding a total of only 13 of these objects in our images within a 500 search area. Auxiliary optical, radio and X-ray catalogues were cross referenced highlighting a small population of SNRs and SNR candidates common to multi frequency domains.

scholarly journals DEEP RADIO CONTINUUM IMAGING OF THE DWARF IRREGULAR GALAXY IC 10: TRACING STAR FORMATION AND MAGNETIC FIELDS

2011 ◽  
Vol 739 (1) ◽  
pp. L23 ◽  
Author(s):  
V. Heesen ◽  
U. Rau ◽  
M. P. Rupen ◽  
E. Brinks ◽  
D. A. Hunter
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Radio Continuum ◽  
Irregular Galaxy ◽  
Ic 10

scholarly journals Discovery of a new supernova remnant G21.8−3.0

2020 ◽  
Vol 493 (2) ◽  
pp. 2188-2194 ◽  
Author(s):  
X Y Gao ◽  
P Reich ◽  
W Reich ◽  
L G Hou ◽  
J L Han
Keyword(s):  
Spectral Index ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Supernova Remnant ◽  
Galactic Plane ◽  
Infrared Emission ◽  
Radio Continuum ◽  
Source Spectrum ◽  
Polarized Emission ◽  
Eastern Half

ABSTRACT Sensitive radio continuum surveys of the Galactic plane are ideal for discovering new supernova remnants (SNRs). From the Sino-German λ6-cm polarization survey of the Galactic plane, an extended shell-like structure has been found at ℓ = 21${^{\circ}_{.}}$8, b = −3${^{\circ}_{.}}$0, which has a size of about 1°. New observations were made with the Effelsberg 100-m radio telescope at λ11 cm to estimate the source spectrum, together with Urumqi λ6-cm and Effelsberg λ21-cm data. The spectral index of G21.8−3.0 was found to be α = −0.72 ± 0.16. Polarized emission was mostly detected in the eastern half of G21.8−3.0 at both λ6 and λ11 cm. These properties, together with the Hα filament along its northern periphery and the lack of infrared emission, indicate that the emission is non-thermal, as is usual in shell-type SNRs.

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