- ID:
- ivo://CDS.VizieR/J/MNRAS/431/2453
- Title:
- SN1996cr radio observations
- Short Name:
- J/MNRAS/431/2453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present newly reduced archival radio observations of SN 1996cr in the Circinus Galaxy from the Australia Telescope Compact Array and the Molonglo Observatory Synthesis Telescope, and attempt to model its radio light curves using recent hydrodynamical simulations of the interaction between the supernova (SN) ejecta and the circumstellar material (CSM) at X-ray wavelengths. The radio data within the first 1000d show clear signs of free-free absorption (FFA), which decreases gradually and is minimal above 1.4GHz after day ~3000. Constraints on the FFA optical depth provide estimates of the CSM free electron density, which allows insight into the ionization of SN 1996cr's CSM and offers a test on the density distribution adopted by the hydrodynamical simulation. The intrinsic spectral index of the radiation shows evidence for spectral flattening, which is characterized by {alpha}=0.852+/-0.002 at day 3000 and a decay rate of {Delta}{alpha}=-0.014+/-0.001yr^-1^. The striking similarity in the spectral flattening of SN 1987A, SN 1993J and SN 1996cr suggests this may be a relatively common feature of SNe/CSM shocks. We adopt this spectral index variation to model the synchrotron radio emission of the shock, and consider several scalings that relate the parameters of the hydrodynamical simulation to the magnetic field and electron distribution. The simulated light curves match the large-scale features of the observed light curves, but fail to match certain tightly constraining sections. This suggests that simple energy density scalings may not be able to account for the complexities of the true physical processes at work, or alternatively, that the parameters of the simulation require modification in order to accurately represent the surroundings of SN 1996cr.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/580/A51
- Title:
- SNR G18.8+0.3 data cubes
- Short Name:
- J/A+A/580/A51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a previous paper we investigated the molecular environment toward the eastern border of the supernova remnant (SNR) G18.8+0.3. Continuing with the study of the surroundings of this SNR, we now focus on its southern border, which in the radio continuum emission shows a very peculiar morphology with a corrugated corner and a very flattened southern flank. We observed two regions toward the south of SNR G18.8+0.3 using the Atacama Submillimeter Telescope Experiment (ASTE) in the ^12^CO J=3-2. One of these regions was also surveyed in ^13^ CO and C^18^O J=3-2. The angular and spectral resolution of these observations were 22" and 0.11km/s. We compared the CO emission to 20cm radio continuum maps obtained as part of the Multi-Array Galactic Plane Imaging Survey (MAGPIS) and 870um dust emission extracted from the APEX Telescope Large Area Survey of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A71
- Title:
- SNR G11.0-0.0 1.4GHz radio continuum image
- Short Name:
- J/A+A/587/A71
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The main goal of this paper is to provide new insights on the origin of the observable flux of {gamma} rays from HESS J1809-193 using new high-quality observations in the radio domain. We used the Expanded Very Large Array (now known as the Karl G. Jansky Very large Array, JVLA) to produce a deep full-synthesis imaging at 1.4GHz of the vicinity of PSR J1809-1917. These data were used in conjunction with 12CO observations from the James Clerk Maxwell Telescope in the transition line J=3-2 and atomic hydrogen data from the Southern Galactic Plane Survey to investigate the properties of the interstellar medium in the direction of the source HESS J1809-193.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A52
- Title:
- SNR G272.2-3.2 XMM and Chandra observations
- Short Name:
- J/A+A/552/A52
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to study the spatial distribution of the physical and chemical properties of the X-ray emitting plasma of the supernova remnant G272.2-3.2, in order to obtain important constraints on its ionization stage, the progenitor supernova explosion, and the age of the remnant. We report on combined XMM-Newton and Chandra images, median photon energy maps, silicon and sulfur equivalent width maps, and a spatially resolved spectral analysis for a set of regions of the remnant.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A41
- Title:
- SNR IKT 16 X-ray image
- Short Name:
- J/A+A/584/A41
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IKT 16 is an X-ray and radio-faint supernova remnant (SNR) in the Small Magellanic Cloud (SMC). A detailed X-ray study of this SNR with XMM-Newton confirmed the presence of a hard X-ray source near its centre, indicating the detection of the first composite SNR in the SMC. With a dedicated Chandra observation we aim to resolve the point source and confirm its nature. We also acquire new ATCA observations of the source at 2.1GHz with improved flux density estimates and resolution. We perform detailed spatial and spectral analysis of the source. With the highest resolution X-ray and radio image of the centre of the SNR available today, we resolve the source and confirm its pulsar wind nebula (PWN) nature. Further, we constrain the geometrical parameters of the PWN and perform spectral analysis for the point source and the PWN separately. We also test for the radial variations of the PWN spectrum and its possible east west asymmetry. The X-ray source at the centre of IKT 16 can be resolved into a symmetrical elongated feature centring a point source, the putative pulsar. Spatial modelling indicates an extent of 5.2" of the feature with its axis inclined at 82{deg} east from north, aligned with a larger radio feature consisting of two lobes almost symmetrical about the X-ray source. The picture is consistent with a PWN which has not yet collided with the reverse shock. The point source is about three times brighter than the PWN and has a hard spectrum of spectral index 1.1 compared to a value 2.2 for the PWN. This points to the presence of a pulsar dominated by non-thermal emission. The expected dE/dt is ~10^37^erg/s and spin period <100ms. However, the presence of a compact nebula unresolved by Chandra at the distance of the SMC cannot completely be ruled out.
- ID:
- ivo://CDS.VizieR/J/ApJS/187/495
- Title:
- SNRs in M33 from optical and X-ray
- Short Name:
- J/ApJS/187/495
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M33 contains a large number of emission nebulae identified as supernova remnants (SNRs) based on the high [SII]:H{alpha} ratios characteristic of shocked gas. Using Chandra data from the ChASeM33 survey with a 0.35-2keV sensitivity of ~2x10^34^erg/s, we have detected 82 of 137 SNR candidates, yielding confirmation of (or at least strongly support for) their SNR identifications. A spectral analysis of the seven X-ray brightest SNRs reveals that two, G98-31 and G98-35, have spectra that appear to indicate enrichment by ejecta from core-collapse supernova explosions. We have used a combination of new and archival optical and radio observations to attempt to better understand why some objects are detected as X-ray sources and others are not. We have also developed a morphological classification scheme for the optically identified SNRs and discussed the efficacy of this scheme as a predictor of X-ray detectability. Finally, we have compared the SNRs found in M33 to those that have been observed in the Galaxy and the Magellanic Clouds.
- ID:
- ivo://CDS.VizieR/J/MNRAS/429/189
- Title:
- SNRs in six nearby galaxies
- Short Name:
- J/MNRAS/429/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a study of optically emitting supernova remnants (SNRs) in six nearby galaxies (NGC 2403, 3077, 4214, 4395, 4449 and 5204) based on deep narrow-band H{alpha} and [SII] images as well as spectroscopic observations. The SNR classification was based on the detected sources that fulfil the well-established emission-line flux criterion of [SII]/H{alpha}>0.4. This study revealed ~400 photometric SNRs down to a limiting H{alpha} flux of 10^-15^erg/s/cm^2^. Spectroscopic observations confirmed the shock-excited nature of 56 out of the 96 sources with ([SII]/H{alpha})_phot_>0.3 (our limit for an SNR classification) for which we obtained spectra. 11 more sources were spectroscopically identified as SNRs although their photometric [SII]/H{alpha} ratio was below 0.3. We discuss the properties of the optically detected SNRs in our sample for different types of galaxies and hence different environments, in order to address their connection with the surrounding interstellar medium. We find that there is a difference in [NII]/H{alpha} line ratios of the SNR populations between different types of galaxies which indicates that this happens due to metallicity. We cross-correlate parameters of the optically detected SNRs ([SII]/H{alpha} ratio, luminosity) with parameters of coincident X-ray-emitting SNRs, resulted from our previous studies on the same sample of galaxies, in order to understand their evolution and investigate possible selection effects. We do not find a correlation between their H{alpha} and X-ray luminosities, which we attribute to the presence of material in a wide range of temperatures. We also find evidence for a linear relation between the number of luminous optical SNRs (10^37^erg/s) and star formation rate in our sample of galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/354
- Title:
- Sources around Tycho's Supernova 1572
- Short Name:
- J/MNRAS/439/354
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With archival and new Hubble Space Telescope observations, we have refined the space-velocity measurements of the stars in the central region of the remnant of Tycho's supernova (SN) 1572, one of the historical Galactic Type Ia supernova remnants (SNRs). We derived a proper motion for Tycho-G of (pmRAcosDE;pmDE) J2000.0 =(-2.63;,-3.98)+/-(0.06;,0.04)[formal errors] +/-(0.18;0.10)[expected errors]mas/yr. If the star were at the distance of the SNR (taken here to be 2.83kpc), its velocity would be V_b_=-51+/-1.5km/s. We also reconstruct the binary orbit that Tycho-G should have followed if it were the surviving companion of SN 1572. We redetermine the Ni abundance of this star and compare it with new abundance data from stars of the Galactic disc, finding that [Ni/Fe] is about 1.7{sigma} above the Galactic trend. From the high velocity of Tycho-G perpendicular to the Galactic plane (-90+/-3km/s<=V_b_<=-45+/-1km/s, for the allowed range of distances to the star), its metallicity and its Ni excess, we find the probability of it being a chance interloper to be P<~0.00037 at most. The projected rotational velocity of the star should be below current observational limits. The projected position of Tycho-G is, within the uncertainties, consistent with the centroid of the X-ray emission of Tycho's SNR; moreover, its brightness is generally consistent with the post-explosion evolution of the luminosity of an SN companion. Among the other 23 stars having V<22mag and located within 42-arcsec from the X-ray centroid, only 4 are at distances compatible with that of the SNR, and none of them shows any peculiarity. Therefore, if even Tycho-G is not the surviving companion of SN 1572, the absence of other viable candidates does favour the merging of two white dwarfs as the producer of the SN.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A10
- Title:
- Spectroscopic mapping of supernova remnant N49
- Short Name:
- J/A+A/595/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Physical conditions inside a supernova remnant can vary significantly between different positions. However, typical observational data of supernova remnants are integrated data or contemplate specific portions of the remnant. We study the spatial variation in the physical properties of the N49 supernova remnant based on a spectroscopic mapping of the whole nebula. Long-slit spectra were obtained with the slit (~4'x1.03") aligned along the east-west direction from 29 different positions spaced by 2" in declination. A total of 3248 1D spectra were extracted from sections of 2" of the 2D spectra. More than 60 emission lines in the range 3550{AA} to 8920{AA} were measured in these spectra. Maps of the fluxes and of intensity ratios of these emission lines were built with a spatial resolution of 2"x2".
- ID:
- ivo://CDS.VizieR/J/A+A/655/A10
- Title:
- Supernova remnant G107.0+9.0 radio images
- Short Name:
- J/A+A/655/A10
- Date:
- 07 Mar 2022 07:14:09
- Publisher:
- CDS
- Description:
- The vast majority of Galactic supernova remnants (SNRs) were detected by their synchrotron radio emission. Recently, the evolved SNR G107.0+9.0 with a diameter of about 3D or 75pc up to 100pc in size was optically detected with an indication of faint associated radio emission. This SNR requires a detailed radio study. We searched for radio emission from SNR G107.0+9.0 by analysing new data from the Effelsberg 100-m and the Urumqi 25-m radio telescopes in addition to available radio surveys. Radio SNRs outside of the Galactic plane, where confusion is rare, must be very faint if they have not been identified so far. Guided by the H{alpha} emission of G107.0+9.0, we separated its radio emission from the Galactic large-scale emission. Radio emission from SNR G107.0+9.0 is detected between 22MHz and 4.8GHz with a steep non-thermal spectrum, which confirms G107.0+9.0 as an SNR. Its surface brightness is among the lowest known for Galactic SNRs. Polarised emission is clearly detected at 1.4GHz but is fainter at 4.8GHz. We interpret the polarised emission as being caused by a Faraday screen associated with G107.0+9.0 and its surroundings. Its ordered magnetic field along the line of sight is below 1-microG. At 4.8GHz, we identified a depolarised filament along the western periphery of G107.0+9.0 with a magnetic field strength along the line of sight B_parallel_~15-microG, which requires magnetic field compression. G107.0+9.0 adds to the currently small number of known, evolved, large-diameter, low-surface-brightness Galactic SNRs. We have shown that such objects can be successfully extracted from radio-continuum surveys despite the dominating large-scale diffuse Galactic emission.
