- ID:
- ivo://CDS.VizieR/J/MNRAS/446/943
- Title:
- Optical supernova remnants in nearby galaxies
- Short Name:
- J/MNRAS/446/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present the most up-to-date list of nearby galaxies with optically detected supernova remnants (SNRs). We discuss the contribution of the H{alpha} flux from the SNRs to the total H{alpha} flux and its influence on the derived star formation rate (SFR) for 18 galaxies in our sample. We found that the contribution of SNR flux to the total H{alpha} flux is 5+/-5%. Due to the observational selection effects, the SNR contamination of SFRs derived herein represents only a lower limit.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/246/169
- Title:
- Radio continuum around G 73.9+0.9
- Short Name:
- J/MNRAS/246/169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A field centered on the galactic supernova remnant (SNR) G073.9+00.9 was mapped in the continuum at 408 and 1420 MHz with the Dominion Radio Astrophysical Observatory (DRAO). The interferometer observations, of resolution 3.4x5.8 arcmin^2^ and 1.0x1.7 arcmin^2^ respectively, were complemented with single-dish data so that the resulting maps are sensitive to all structures down to the synthesized beam. Note that this list is part of the DRAO Penticton P-survey Database (Catalog <VIII/55>)
- ID:
- ivo://CDS.VizieR/J/A+A/241/551
- Title:
- Radio continuum in Cygnus X region
- Short Name:
- J/A+A/241/551
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cygnus X region has been observed at 408 and 1420 MHz with the Dominion Radio Astrophysical Observatory (DRAO), with an angular resolution of 3.5x5.2 and 1.0x1.5 arcmin.
- ID:
- ivo://CDS.VizieR/J/AJ/137/3869
- Title:
- Radio SNRs in 4 irregular galaxies
- Short Name:
- J/AJ/137/3869
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We survey four nearby irregular galaxies for radio supernova remnants (SNRs) using deep (1{sigma}~20uJy), high-resolution (~20pc) Very Large Array continuum data at 20, 6, and 3.6cm. We identify discrete sources in these galaxies and use radio spectral indices and H{alpha} images to categorize them as SNRs, HII regions, or background radio galaxies. Our classifications are generally in good agreement with the literature. We identify a total of 43 SNR candidates: 23 in NGC 1569, seven in NGC 4214, five in NGC 2366, and eight in NGC 4449. Only one SNR - the well-studied object J1228+441 in NGC 4449 - is more luminous at 20cm than Cas A. By comparing the total thermal flux density in each galaxy with that localized in HII regions, we conclude that a significant fraction must be in a diffuse component or in low-luminosity HII regions.
- ID:
- ivo://CDS.VizieR/J/ApJ/703/370
- Title:
- Radio SNRs in nearby galaxies
- Short Name:
- J/ApJ/703/370
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compile radio supernova remnant (SNR) samples from the literature for 19 nearby galaxies ranging from the SMC to Arp 220, and use this data to constrain the SNR luminosity function (LF) at 20cm. We find that radio SNR populations are strikingly similar across galaxies. The LF can be described as a power law with constant index and scaling proportional to a galaxy's star formation rate (SFR). Unlike previous authors, we do not find any dependence of SNR luminosity on a galaxy's global interstellar medium density. The observed correlation between the luminosity of a galaxy's brightest SNR and a galaxy's SFR can be completely explained by statistical effects, wherein galaxies with higher SFR more thoroughly sample the high-luminosity end of the SNR LF. The LF is well fitted by a model of SNR synchrotron emission which includes diffusive shock acceleration and magnetic field amplification, if we assume that all remnants are undergoing adiabatic expansion, the densities of star-forming regions are similar across galaxies, and the efficiency of cosmic ray production is constant.
- ID:
- ivo://CDS.VizieR/J/A+AS/115/345
- Title:
- Radio sources in fields near G160.9+2.6 (HB9)
- Short Name:
- J/A+AS/115/345
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of the 408MHz and 1420MHz radio sources in the region centered near Right Ascension 4h58m and Declination 46degrees (epoch 1950), i.e. near the supernova remnant HB9. The observations were made with the Synthesis Telescope at the Dominion Radio Astrophysical Observatory, near Penticton, Canada. 494 sources at 408MHz and 255 sources at 1420MHz were detected. 408-1420MHz spectral indices for 101 common sources were derived. The 408MHz source list was compared with the 4850MHz sources from the Green Bank catalog. Spectral indices were determined for 165 common sources. We also compared the source lists with the IRAS and ROSAT point source catalogs for that region and have identified 16 radio sources with IRAS point sources and 3 radio sources with X-ray sources.
- 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.
- 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.
