- ID:
- ivo://CDS.VizieR/J/ApJ/786/130
- Title:
- Catalog of M31 SNR candidates
- Short Name:
- J/ApJ/786/130
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of optically emitting supernova remnants (SNRs) in M31 based on H{alpha} and [S II] images in the Local Group Survey. Using these images, we select objects that have [S II]:H{alpha}>0.4 and circular shapes. We identify 156 SNR candidates, of which 76 are newly found objects. We classify these SNR candidates according to two criteria: the SNR progenitor type (Type Ia and core-collapse (CC) SNRs) and the morphological type. Type Ia and CC SNR candidates make up 23% and 77%, respectively, of the total sample. Most of the CC SNR candidates are concentrated in the spiral arms, while the Type Ia SNR candidates are rather distributed over the entire galaxy, including the inner region. The CC SNR candidates are brighter in H{alpha} and [S II] than the Type Ia SNR candidates. We derive a cumulative size distribution of the SNR candidates, finding that the distribution of the candidates with 17<D<50 pc is fitted well by a power law with the power-law index {alpha}=2.53+/-0.04. This indicates that most of the SNR candidates identified in this study appear to be in the Sedov-Taylor phase. The [S II]:H{alpha} distribution of the SNR candidates is bimodal, with peaks at [S II]:H{alpha}~0.4 and~0.9. The properties of these SNR candidates vary little with the galactocentric distance. The H{alpha} and [S II] surface brightnesses show a good correlation with the X-ray luminosity of the SNR candidates that are center-bright.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/174/366
- Title:
- Chandra ACIS survey of M33 (ChaSeM33)
- Short Name:
- J/ApJS/174/366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an overview of the Chandra ACIS Survey of M33 (ChASeM33): A Deep Survey of the Nearest Face-on Spiral Galaxy. The 1.4Ms survey covers the galaxy out to R~18'(~4kpc). These data provide the most intensive, high spatial resolution assessment of the X-ray source populations available for the confused inner regions of M33. The initial source catalog, arising from ~2/3 of the expected survey data, includes 394 sources significant at the 3{sigma} confidence level or greater, down to a limiting luminosity (absorbed) of ~1.6x10^35^ergs/s (0.35-8.0keV). The hardness ratios of the sources separate those with soft, thermal spectra such as supernova remnants from those with hard, nonthermal spectra such as X-ray binaries and background active galactic nuclei. Emission extended beyond the Chandra point-spread function is evident in 23 of the 394 sources. Cross-correlation of the ChASeM33 sources against previous catalogs of X-ray sources in M33 results in matches for the vast majority of the brighter sources and shows 28 ChASeM33 sources within 10" of supernova remnants identified by prior optical and radio searches. This brings the total number of such associations to 31 out of 100 known supernova remnants in M33.
- ID:
- ivo://CDS.VizieR/J/AJ/136/2083
- Title:
- Clumps in NGC 6334 from 450/850um observations
- Short Name:
- J/AJ/136/2083
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 6334 is a galactic star-forming region in Scorpius, heavily obscured by intervening dust. The region consists of several major sites of star formation known previously from far-infrared (IR) and radio-wavelength observations. We present images of NGC 6334 obtained at wavelengths of 850 and 450um with the Submillimeter Common-User Bolometric Array at the James Clerk Maxwell Telescope. These data highlight the distribution of dense cold dust, a particularly striking feature of which is a narrow ridge of emission passing between most of the star-forming centers. We use a clump-finding technique to quantify the distribution of dust emission throughout the region, and we obtain estimates of the sizes, masses, and temperatures of the clump ensemble under simple assumptions.
- ID:
- ivo://CDS.VizieR/J/A+A/531/A26
- Title:
- Clumps in W31 from CO and 875um observations
- Short Name:
- J/A+A/531/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-mass star formation has been a very active field over the past decade; however, most studies have targeted regions of luminosities between 10^4^ and 10^5^L_{sun}_. In contrast to that, the highest mass stars reside in clusters exceeding 10^5^ or even 10^6^L_{sun}_. We want to study the physical conditions associated with the formation of the highest mass stars. To do this, we selected the W31 star-forming complex with a total luminosity of ~6x10^6^L_{sun}_ (comprised of at least two subregions) for a multiwavelength spectral line and continuum study covering wavelengths from the near- and midinfrared via (sub)mm wavelength observations to radio data in the cm regime.
- ID:
- ivo://CDS.VizieR/J/A+A/503/827
- Title:
- 6cm and 11cm polarisation maps of SNR G65.2+5.7
- Short Name:
- J/A+A/503/827
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SNR G65.2+5.7 is one of few supernova remnants (SNRs) that have been optically detected. It is exceptionally bright in X-rays and the optical [O III]-line. Its low surface brightness and large diameter ensure that radio observations of SNR G65.2+5.7 are technically difficult and thus have hardly been completed. Many physical properties of this SNR, such as spectrum and polarization, can only be investigated by radio observations.
- ID:
- ivo://CDS.VizieR/J/A+A/482/783
- Title:
- 6cm and 11cm polarisation maps of SNR S147
- Short Name:
- J/A+A/482/783
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S147 is a large faint shell-type supernova remnant (SNR) known for its remarkable spectral break at cm-wavelength, which is an important physical property to characterize SNR evolution. However, the spectral break is based on radio observations with limited precision. New sensitive observations at high frequencies are required for a detailed study of the spectral properties and the magnetic field structure of S147.
- ID:
- ivo://CDS.VizieR/J/ApJ/878/44
- Title:
- ^13^CO clumps toward the Cassiopeia A supernova remnant
- Short Name:
- J/ApJ/878/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted a large-field simultaneous survey of ^12^CO, ^13^CO, and C^18^O J=1-0 emission toward the Cassiopeia A (Cas A) supernova remnant (SNR), which covers a sky area of 3.5{deg}x3.1{deg}. The Cas giant molecular cloud (GMC) mainly consists of three individual clouds with masses on the order of 10^4^-10^5^M_{sun}_. The total mass derived from the ^13^CO emission of the GMC is 2.1x10^5^M_{sun}_ and is 9.5x10^5^M_{sun}_ from the ^12^CO emission. Two regions with broadened (6-7km/s) or asymmetric ^12^CO line profiles are found in the vicinity (within a 10'x10' region) of the Cas A SNR, indicating possible interactions between the SNR and the GMC. Using the GAUSSCLUMPS algorithm, 547 ^13^CO clumps are identified in the GMC, 54% of which are supercritical (i.e., {alpha}_vir_<2). The mass spectrum of the molecular clumps follows a power-law distribution with an exponent of -2.20. The pixel-by-pixel column density of the GMC can be fitted with a log-normal probability distribution function (N-PDF). The median column density of molecular hydrogen in the GMC is 1.6x10^21^cm^-2^ and half the mass of the GMC is contained in regions with H_2_ column density lower than 3x10^21^cm^-2^, which is well below the threshold of star formation. The distribution of the YSO candidates in the region shows no agglomeration.
- ID:
- ivo://CDS.VizieR/J/A+A/508/1331
- Title:
- CO maps of 3 galactic supernova remnants
- Short Name:
- J/A+A/508/1331
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The field just West of the galactic supernova remnant W28 (l=6.4{deg}, b=-0.2{deg}) harbors 3 of 5 newly-discovered 1720 OH maser spots and two recently-discovered candidate supernova candidates (one of which is a gamma-ray source), as well as several compact and classical HII regions. The aims is to show the interaction of radio supernova remnants with ambient molecular gas in sky field just West of W28.
- ID:
- ivo://CDS.VizieR/J/ApJ/897/83
- Title:
- Component structure in the neightborhood of IC 443
- Short Name:
- J/ApJ/897/83
- Date:
- 11 Mar 2022
- Publisher:
- CDS
- Description:
- We present the results of a detailed investigation into the physical conditions in interstellar material interacting with the supernova remnant (SNR) IC443. Our analysis is based on a comprehensive examination of high-resolution far-ultraviolet spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope of two stars behind IC443. One of our targets (HD43582) probes gas along the entire line of sight through the SNR, while the other (HD254755) samples material located ahead of the primary supernova shock front. We identify low-velocity quiescent gas in both directions and find that the densities and temperatures in these components are typical of diffuse atomic and molecular clouds. Numerous high- velocity components are observed in the absorption profiles of neutral and singly ionized atomic species toward HD43582. These components exhibit a combination of greatly enhanced thermal pressures and significantly reduced dust-grain depletions. We interpret this material as cooling gas in a recombination zone far downstream from shocks driven into neutral gas clumps. The pressures derived for a group of ionized gas components at high positive velocity toward HD43582 are lower than those of the other shocked components, pointing to pressure inhomogeneities across the remnant. A strong, very high velocity component near -620km/s is seen in the absorption profiles of highly ionized species toward HD43582. The velocity of this material is consistent with the range of shock velocities implied by observations of soft thermal X-ray emission from IC443. Moderately high velocity gas toward HD254755 may represent shocked material from a separate foreground SNR.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A64
- Title:
- CO observations of the IC443 SNR
- Short Name:
- J/A+A/644/A64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Supernova remnants (SNRs) represent a major feedback source from stars in the interstellar medium of galaxies. During the latest stage of supernova explosions, shock waves produced by the initial blast modify the chemistry of gas and dust, inject kinetic energy into the surroundings, and may alter star formation characteristics. Simultaneously, gamma-ray emission is generated by the interaction between the ambient medium and cosmic rays (CRs), including those accelerated in the early stages of the explosion. We study the stellar and interstellar contents of IC443, an evolved shell-type SNR at a distance of 1.9kpc with an estimated age of 30kyr. We aim to measure the mass of the gas and characterize the nature of infrared point sources within the extended G region, which corresponds to the peak of gamma-ray emission detected by VERITAS and Fermi. We performed 10'x10' mapped observations of ^12^CO, ^13^CO J=1-0, J=2-1, and J=3-2 pure rotational lines, as well as C^18^O J=1-0 and J=2-1 obtained with the IRAM 30m and APEX telescopes over the extent of the gamma-ray peak to reveal the molecular structure of the region. We first compared our data with local thermodynamic equilibrium models. We estimated the optical depth of each line from the emission of the isotopologs ^13^CO and C^18^O. We used the population diagram and large velocity gradient assumption to measure the column density, mass, and kinetic temperature of the gas using ^12^CO and ^13^CO lines. We used complementary data (stars, gas, and dust at multiple wavelengths) and infrared point source catalogs to search for protostar candidates. Our observations reveal four molecular structures: a shocked molecular clump associated with emission lines extending between -31 and 16km/s, a quiescent, dark cloudlet associated with a line width of ~2km/s, a narrow ring-like structure associated with a line width of ~1.5km/s, and a shocked knot. We measured a total mass of ~230, ~90, ~210, and ~4M_{sun}_, respectively, for the cloudlet, ring-like structure, shocked clump, and shocked knot. We measured a mass of ~1100M_{sun}_ throughout the rest of the field of observations where an ambient cloud is detected. We found 144 protostar candidates in the region. Our results emphasize how the mass associated with the ring-like structure and the cloudlet cannot be overlooked when quantifying the interaction of CRs with the dense local medium. Additionally, the presence of numerous possible protostars in the region might represent a fresh source of CRs, which must also be taken into account in the interpretation of gamma-ray observations in this region.
