- ID:
- ivo://CDS.VizieR/J/other/BSAO/46.62
- Title:
- RATAN observations of Galactic SNRs
- Short Name:
- J/other/BSAO/46.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present radio continuum spectra for 200 Galactic supernova remnants (SNRs) from 220 known and included in Green's (1998, Cat. VII/211) catalog. The spectra can be plotted only for 200 SNRs because about 20 remaining new and weak SNRs (Whiteoak and Green, 1996, Cat. J/A+AS/118/329; Gray, 1994MNRAS.270..847G) have only one-frequency flux density measurements. Spectrum plotting is an "on-line" procedure of the CATS database (Verkhodanov et al., 1997ASPCo.125..322V) created for some other multi-frequency catalogs. These spectra include most of the measurements available in literature, as well as multi-frequency measurements of nearly 120 SNRs with the RATAN-600 radio telescope in 1, 2 and 4 Galactic quadrants and from the Galactic plane survey at 960 and 3900MHz (Trushkin, 1986ATsir1453....4T, 1987AISAO..25...84T, 1989, Ph.D. Thesis. SAO, Nizhnij Arkhyz, 1996BSAO...41...64T, 1998BSAO...46...62T). The measurements have been placed on the same absolute flux density scale of Baars (1977A&A....61...99B) as in the paper by Kassim (1989ApJ...347..915K), using the correcting factor from the compiled catalog (Kuhr et al., 1981, Cat. VIII/5). The presented compilation has given a possibility of plotting quite accurate spectra with the thermal plasma free-free absorption in fitting the spectra accounted for.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/612/A6
- Title:
- RX J1713.7-3946 HESS spectrum
- Short Name:
- J/A+A/612/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7-3946 (also known as G347.3-0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7-3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048{deg} (0.036{deg} above 2TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's location. The new H.E.S.S. image of RX J1713.7-3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism.
- ID:
- ivo://CDS.VizieR/J/ApJ/795/170
- Title:
- Sample SNRs for M31 and M33
- Short Name:
- J/ApJ/795/170
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Hubble Space Telescope photometry to measure star formation histories, we age-date the stellar populations surrounding supernova remnants (SNRs) in M31 and M33. We then apply stellar evolution models to the ages to infer the corresponding masses for their supernova progenitor stars. We analyze 33 M33 SNR progenitors and 29 M31 SNR progenitors in this work. We then combine these measurements with 53 previously published M31 SNR progenitor measurements to bring our total number of progenitor mass estimates to 115. To quantify the mass distributions, we fit power laws of the form dN/dM{prop.to}M^-{alpha}^. Our new larger sample of M31 progenitors follows a distribution with {alpha}=4.4_-0.4_^+0.4^, and the M33 sample follows a distribution with {alpha}=3.8_-0.5_^+0.4^. Thus both samples are consistent within the uncertainties, and the full sample across both galaxies gives {alpha}=4.2_-0.3_^+0.3^. Both the individual and full distributions display a paucity of massive stars when compared to a Salpeter initial mass function, which we would expect to observe if all massive stars exploded as SN that leave behind observable SNR. If we instead fix {alpha}=2.35 and treat the maximum mass as a free parameter, we find M_max_~35-45 M_{sun}_, indicative of a potential maximum cutoff mass for SN production. Our results suggest that either SNR surveys are biased against finding objects in the youngest (<10 Myr old) regions, or the highest mass stars do not produce SNe.
- ID:
- ivo://CDS.VizieR/J/ApJ/869/66
- Title:
- Search for extraterrestrial intelligence with ATA
- Short Name:
- J/ApJ/869/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a novel radio autocorrelation search for extraterrestrial intelligence. For selected frequencies across the terrestrial microwave window (1-10GHz), observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 4Hz, which are capable of carrying substantial messages with symbol rates from 4 to 10^6^Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux >~1Jy over the sampled bandwidth (quasars, pulsars, supernova remnants, and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial repetitive, phase or frequency modulation. The rest of the observations were directed mostly toward exoplanet stars with no previously discovered continuum flux. No signals attributable to extraterrestrial technology were found in this study. We conclude that the maximum probability that future observations like the ones described here will reveal repetitively modulated emissions is less than 5% for continuum sources and exoplanets alike. The paper concludes by describing a new approach to expanding this survey to many more targets and much greater sensitivity using archived data from interferometers all over the world.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A47
- Title:
- Sgr B2(N) and Sgr B2(M) IRAM 30m line survey
- Short Name:
- J/A+A/559/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The discovery of amino acids in meteorites fallen to Earth and the detection of glycine, the simplest of them, in samples returned from a comet to Earth strongly suggest that the chemistry of the interstellar medium is capable of producing such complex organic molecules and that they may be widespread in our Galaxy. Our goal is to investigate the degree of chemical complexity that can be reached in the interstellar medium, in particular in dense star-forming regions. We performed an unbiased, spectral line survey toward Sgr B2(N) and (M), two regions where high-mass stars are formed, with the IRAM 30m telescope in the 3mm atmospheric transmission window. Partial surveys at 2 and 1.3mm were performed in parallel. The spectra were analyzed with a simple radiative transfer model that assumes local thermodynamic equilibrium but takes optical depth effects into account.
- 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.
- 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.
