Radio continuum observations of the galactic supernova remnant Vela Z (G266.2-1.2)

ABSTRACT We present the results from the Suzaku X-ray Imaging Spectrometer observation of the mixed-morphology supernova remnant (SNR) HB9 (G160.9+2.6). We discovered recombining plasma (RP) in the western Suzaku observation region and the spectra here are well described by a model having collisional ionization equilibrium (CIE) and RP components. On the other hand, the X-ray spectra from the eastern Suzaku observation region are best reproduced by the CIE and non-equilibrium ionization model. We discuss possible scenarios to explain the origin of the RP emission based on the observational properties and concluded that the rarefaction scenario is a possible explanation for the existence of RP. In addition, the gamma-ray emission morphology and spectrum within the energy range of 0.2–300 GeV are investigated using 10 yr of data from the Fermi Large Area Telescope (LAT). The gamma-ray morphology of HB9 is best described by the spatial template of radio continuum emission. The spectrum is well fit to a log-parabola function and its detection significance was found to be 25σ. Moreover, a new gamma-ray point source located just outside the south-east region of the SNR’s shell was detected with a significance of 6σ. We also investigated the archival H i and CO data and detected an expanding shell structure in the velocity range of $-10.5$ and $+1.8$ km s−1 that is coinciding with a region of gamma-ray enhancement at the southern rim of the HB9 shell.

Download Full-text

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314001161 ◽

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.

Download Full-text

On the integrated continuum radio spectrum of supernova remnant W44 (G34.7-0.4): New insights from Planck

Serbian Astronomical Journal ◽

10.2298/saj150715004o ◽

2015 ◽

pp. 29-37 ◽

Cited By ~ 3

Author(s):

D. Onic

Keyword(s):

Supernova Remnant ◽

Dust Emission ◽

Radio Spectrum ◽

Radio Continuum ◽

Continuum Spectrum ◽

Data Points ◽

Emission Models ◽

Continuum Radio ◽

Emission Detection

In this paper, the integrated continuum radio spectrum of supernova remnant (SNR) W44 was analyzed up to 70 GHz, testing the different emission models that can be responsible for its particular shape. The observations by the Planck space telescope made it possible to analyze the high frequency part of radio emission from SNRs. Although the quality of radio continuum spectrum (a high scatter of data points at same frequencies) prevents us to make definite conclusions, the possibility of spinning dust emission detection towards this remnant is emphasized. In addition, a concave-down feature, due to synchrotron losses, can not be definitely dismissed by the present knowledge of the integrated radio continuum spectrum of this SNR.

Download Full-text

G18.95-1.1, A Composite Supernova Remnant Interacting with the Ambient Interstellar Medium

International Astronomical Union Colloquium ◽

10.1017/s0252921100102465 ◽

1988 ◽

Vol 101 ◽

pp. 253-256

Author(s):

E. Fürst ◽

W. Reich ◽

E. Hummel ◽

Y. Sofue

Keyword(s):

Spectral Line ◽

Interstellar Medium ◽

Radio Source ◽

Supernova Remnant ◽

Radio Continuum ◽

New Radio ◽

Galactic Radio

AbstractNew radio continuum and spectral line observations of the Galactic radio source G18.95-1.1 are reported. The distance to G18.95-1.1 is 2 kpc as derived from HI-21 cm spectral line observations. These data also indicate an interaction with the interstellar medium. The radio continuum observations classify G18.95-1.1 as a composite supernova remnant.

Download Full-text

Radio Continuum Emission from the Central Stars of M20, and the Detection of a New Supernova Remnant near M20

The Astrophysical Journal ◽

10.1086/309352 ◽

2000 ◽

Vol 540 (2) ◽

pp. 842-850 ◽

Cited By ~ 20

Author(s):

F. Yusef‐Zadeh ◽

Mark Shure ◽

Mark Wardle ◽

N. Kassim

Keyword(s):

Supernova Remnant ◽

Radio Continuum ◽

Continuum Emission ◽

Central Stars

Download Full-text

New composite supernova remnant toward HESS J1844-030?

Astronomy and Astrophysics ◽

10.1051/0004-6361/201834734 ◽

2019 ◽

Vol 626 ◽

pp. A65

Author(s):

A. Petriella

Keyword(s):

Supernova Remnant ◽

High Energy ◽

Radio Continuum ◽

Pressure Balance ◽

High Energy Radiation ◽

X Ray ◽

Galactic Source ◽

Very High Energy ◽

The Magnetic Field ◽

Very High

Aims. HESS J1844-030 is a newly confirmed TeV source in the direction of the X-ray pulsar wind nebula (PWN) candidate G29.4+0.1 and the complex radio source G29.37+0.1, which is likely formed by the superposition of a background radio galaxy and a Galactic supernova remnant (SNR). Many scenarios have been proposed to explain the origin of HESS J1844-030, based on several sources that are capable of producing very high energy radiation. We investigate the possible connection between the SNR, the PWN G29.4+0.1, and HESS J1844-030 to shed light on the astrophysical origin of the TeV emission. Methods. We performed an imaging and spectral study of the X-ray emission from the PWN G29.4+0.1 using archival observations obtained with the Chandra and XMM-Newton telescopes. Public radio continuum and HI data were used to derive distance constraints for the SNR that is linked to G29.37+0.1 and to investigate the interstellar medium where it is expanding. We applied a simple model of the evolution of a PWN inside an SNR to analyze the association between G29.4+0.1 and the radio emission from G29.37+0.1. We compared the spectral properties of the system with the population of TeV PWNe to investigate if HESS J1844-030 is the very high energy counterpart of the X-ray PWN G29.4+0.1. Results. Based on the morphology and spectral behavior in the X-ray band, we conclude that G29.4+0.1 is a PWN and that a point source embedded on it is the powering pulsar. The HI data revealed that the SNR linked to G29.37+0.1 is a Galactic source at 6.5 kpc and expanding in a nonuniform medium. From the analysis of the pulsar motion and the pressure balance at the boundary of X-ray emission, we conclude that G29.4+0.1 could be a PWN that is located inside its host remnant, forming a new composite SNR. Based on the magnetic field of the PWN obtained from the X-ray luminosity, we found that the population of electrons producing synchrotron radiation in the keV band can also produce IC photons in the TeV band. This suggests that HESS J1844-030 could be the very high energy counterpart of G29.4+0.1.

Download Full-text

G51.04+0.07 and its environment: Identification of a new Galactic supernova remnant at low radio frequencies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832995 ◽

2018 ◽

Vol 616 ◽

pp. A98 ◽

Cited By ~ 2

Author(s):

L. Supan ◽

G. Castelletti ◽

W. M. Peters ◽

N. E. Kassim

Keyword(s):

Radio Emission ◽

Flux Density ◽

Supernova Remnant ◽

Low Frequency ◽

Neutral Hydrogen ◽

Radio Continuum ◽

Very Large Array ◽

Continuum Spectrum ◽

Galactic Emission ◽

Nonthermal Radio Emission

We have identified a new supernova remnant (SNR), G51.04+0.07, using observations at 74 MHz from the Very Large Array Low-Frequency Sky Survey Redux (VLSSr). Earlier, higher frequency radio continuum, recombination line, and infrared data had correctly inferred the presence of nonthermal radio emission within a larger, complex environment including ionised nebulae and active star formation. However, our observations have allowed us to redefine at least one SNR as a relatively small source (7.′5 × 3′in size) located at the southern periphery of the originally defined SNR candidate G51.21+0.11. The integrated flux density of G51.04+0.07 at 74 MHz is 6.1 ± 0.8 Jy, while its radio continuum spectrum has a slope α = −0.52 ± 0.05 (S v ∝ vα), typical of a shell-type remnant. We also measured spatial variations in the spectral index between 74 and 1400 MHz across the source, ranging from a steeper spectrum (α = −0.50 ± 0.04) coincident with the brightest emission to a flatter component (α = −0.30 ± 0.07) in the surrounding fainter region. To probe the interstellar medium into which the redefined SNR is likely evolving, we have analysed the surrounding atomic and molecular gas using the 21 cm neutral hydrogen (HI) and 13CO(J = 1 − 0) emissions. We found that G51.04+0.07 is confined within an elongated HI cavity and that its radio emission is consistent with the remains of a stellar explosion that occurred ~6300 yr ago at a distance of 7.7 ± 2.3 kpc. Kinematic data suggest that the newly discovered SNR lies in front of HII regions in the complex, consistent with the lack of a turnover in the low frequency continuum spectrum. The CO observations revealed molecular material that traces the central and northern parts of G51.04+0.07. The interaction between the cloud and the radio source is not conclusive and motivates further study. The relatively low flux density (~1.5 Jy at 1400 MHz) of G51.04+0.07 is consistent with this and many similar SNRs lying hidden along complex lines of sight towards inner Galactic emission complexes. It would also not be surprising if the larger complex studied here hosted additional SNRs.

Download Full-text

Multifrequency radio observations of SNR J0536-6735 (N 59B) with associated pulsar

Serbian Astronomical Journal ◽

10.2298/saj1284069b ◽

2012 ◽

pp. 69-76 ◽

Cited By ~ 8

Author(s):

L.M. Bozzetto ◽

M.D. Filipovic ◽

E.J. Crawford ◽

Horta de ◽

M. Stupar

Keyword(s):

Flux Density ◽

Supernova Remnant ◽

Optical Emission ◽

Shell Morphology ◽

Radio Continuum ◽

Continuum Emission ◽

Density Estimates ◽

Hii Region ◽

Pulsar Wind ◽

Compact Array

We present a study of new Australian Telescope Compact Array (ATCA) observations of supernova remnant, SNR J0536-6735. This remnant appears to follow a shell morphology with a diameter of D=36x29 pc (with 1 pc uncertainty in each direction). There is an embedded HII region on the northern limb of the remnant which made various analysis and measurements (such as flux density, spectral index and polarisation) difficult. The radio-continuum emission followed the same structure as the optical emission, allowing for extent and flux density estimates at 20 cm. We estimate the surface brightness at 1 GHz of 2.55x10?21 Wm?2 Hz?1 sr?1 for the SNR. Also, we detect a distinctive radio-continuum point source which confirms the previous suggestion of this remnant being associated with pulsar wind nebula (PWN). The tail of this remnant is not seen in the radio-continuum images and is only seen in the optical and X-ray images.

Download Full-text

ALMA Observations of Supernova Remnant N49 in the LMC. I. Discovery of CO Clumps Associated with X-Ray and Radio Continuum Shells

The Astrophysical Journal ◽

10.3847/1538-4357/aacfff ◽

2018 ◽

Vol 863 (1) ◽

pp. 55 ◽

Cited By ~ 8

Author(s):

Y. Yamane ◽

H. Sano ◽

J. Th. van Loon ◽

M. D. Filipović ◽

K. Fujii ◽

...

Keyword(s):

Supernova Remnant ◽

Radio Continuum ◽

X Ray

Download Full-text

Spectropolarimetry of supernova remnant G296.5 + 10.0

Proceedings of the International Astronomical Union ◽

10.1017/s1743921309030373 ◽

2008 ◽

Vol 4 (S259) ◽

pp. 141-144

Author(s):

Lisa Harvey-Smith ◽

Bryan M. Gaensler ◽

C.-Y. Ng ◽

Anne J. Green

Keyword(s):

Supernova Remnant ◽

Galactic Halo ◽

Radio Continuum ◽

Continuum Emission ◽

Smooth Component ◽

Rotation Measure ◽

Pixel Image ◽

Spectral Channels ◽

The Magnetic Field ◽

Compact Array

AbstractRadio continuum emission from the supernova remnant G296.5 + 10.0 was observed using the Australia Telescope Compact Array. Using a 104 MHz bandwidth split into 13 × 8 MHz spectral channels, it was possible to produce a pixel-by-pixel image of Rotation Measure (RM) across the entire remnant. A lack of correlation between RM and X-ray surface brightness reveals that the RMs originate from outside the remnant. Using this information, we will characterise the smooth component of the magnetic field within the supernova remnant and attempt to probe the magneto-ionic structure and turbulent scale sizes in the ISM and galactic halo along the line-of-sight.

Download Full-text