- ID:
- ivo://CDS.VizieR/J/A+A/561/A55
- Title:
- Small-diameter sources in Sino-German 6cm survey
- Short Name:
- J/A+A/561/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out the Sino-German 6cm polarisation survey of the Galactic plane at 6cm in total and polarised intensity using the Urumqi 25-m telescope of Xinjiang (formerly Urumqi) Astronomical Observatory, Chinese Academy of Sciences. The angular resolution is 9.5-arcmin. The surveyed area covers 10{deg} to 230{deg} in Galactic longitude and absolute Galactic latitudes of up to 5{deg}. The measured rms-noise is about 6.1 mJy/beam area for total intensities and 3.05mJy/beam area for polarised intensities. The survey maps are accessible from http://zmtt.bao.ac.cn/6cm/ .
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/587/A47
- Title:
- SMA 1.3mm image of OMC 1 North
- Short Name:
- J/A+A/587/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The filamentary structure of molecular clouds may set important constraints on the mass distribution of stars forming within them. It is therefore important to understand which physical mechanism dominates filamentary cloud fragmentation and core formation. Orion A is the nearest giant molecular cloud, and its so-called S-shaped filament is a very active star-forming region that is a good target for such a study. We have recently reported on the collapse and fragmentation properties of the northernmost part of this structure, located ~2.4pc north of Orion KL - Orion Molecular Cloud (OMC) 3. As part of our project to study the S-shaped filament, we analyze the fragmentation properties of the northern OMC 1 filament (located <~0.3pc north of Orion KL). This filament is a dense structure previously identified by JCMT/SCUBA submillimeter continuum and VLA NH_3_ observations and was shown to have fragmented into clumps. Our aim is to search for cores and young protostars embedded within OMC 1n and to study how the filament is fragmenting to form them. We observed OMC 1North (hereafter OMC 1n) with the Submillimeter Array (SMA) at 1.3mm and report on our analysis of the continuum data.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/125
- Title:
- SMA obs. of giant molecular clouds in NGC 300
- Short Name:
- J/ApJ/821/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first high angular resolution study of giant molecular clouds (GMCs) in the nearby spiral galaxy NGC 300, based on observations from the Submillimeter Array (SMA). We target eleven 500pc sized regions of active star formation within the galaxy in the ^12^CO(J=2-1) line at 40pc spatial and 1km/s spectral resolution and identify 45 individual GMCs. We characterize the physical properties of these GMCs, and find that they are similar to GMCs in the disks of the Milky Way and other nearby spiral galaxies. For example, the GMC mass spectrum in our sample has a slope of 1.80+/-0.07. Twelve clouds are spatially resolved by our observations, of which ten have virial mass estimates that agree to within a factor of two with mass estimates derived directly from ^12^CO integrated intensity, suggesting that the majority of these GMCs are bound. The resolved clouds show consistency with Larson's fundamental relations between size, linewidth, and mass observed in the Milky Way. We find that the linewidth scales with the size as {Delta}V{propto}R^0.52+/-0.20^, and the median surface density in the subsample is 54M_{sun}_/pc^2^. We detect ^13^CO in four GMCs and find a mean ^12^CO/^13^CO flux ratio of 6.2. Our interferometric observations recover between 30% and 100% of the integrated intensity from the APEX single dish ^12^CO observations of Faesi et al. (2014, J/ApJ/789/81), suggesting the presence of low-mass GMCs and/or diffuse gas below our sensitivity limit. The fraction of APEX emission recovered increases with the SMA total intensity, as well as with the star formation rate.
- ID:
- ivo://CDS.VizieR/J/A+AS/121/321
- Title:
- SMC catalogue of radiosources
- Short Name:
- J/A+AS/121/321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present catalogues of radio sources in the Small Magellanic Cloud from observations with the Parkes radio telescope at 1.42, 2.45, 4.75 and 8.55GHz, and an additional catalogue from the Parkes-MIT-NRAO survey at 4.85GHz. A total of 224 sources were detected at at least one of these frequencies, 60 of which are reported here for the first time as radio sources. We compare positions and flux densities of these sources with previously published results and find no significant positional displacement or flux discrepancies.
1575. SN 1987A 3mm image
- ID:
- ivo://CDS.VizieR/J/A+A/541/L2
- Title:
- SN 1987A 3mm image
- Short Name:
- J/A+A/541/L2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The proximity of core-collapse supernova 1987A (SN 1987A) in the Large Magellanic Cloud (LMC) and its rapid evolution make it a unique case study of the development of a young supernova remnant. We aim at resolving the remnant of SN 1987A for the first time in the 3-mm band (at 94GHz).
- 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/593/A18
- Title:
- SN 2008iz 4.8 and 8.4GHz images
- Short Name:
- J/A+A/593/A18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on multi-frequency Very Large Array (VLA) and Very Long Baseline Interferometry (VLBI) radio observations for a monitoring campaign of supernova SN 2008iz in the nearby irregular galaxy M82.
- 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/640/A74
- Title:
- SOLIS. VIII. L1157-B1 spectra
- Short Name:
- J/A+A/640/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Contrary to what is expected from models of Galactic chemical evolution (GCE), the isotopic fractionation of silicon (Si) in the Galaxy has been recently found to be constant. This finding calls for new observations, also at cores scales, to re-evaluate the fractionation of Si. L1157-B1 is one of the outflow shocked regions along the blue-shifted outflow driven by the Class 0 protostar L1157-mm, and is an ideal laboratory to study the material ejected from the grains in very short timescales, i.e. its chemical composition is representative of the composition of the grains. We imaged ^28^SiO, ^29^SiO and ^30^SiO J = 2-1 emission towards L1157-B1 and B0 with the NOrthern Extended Millimeter Array (NOEMA) interferometer as part of the Seeds of Life in Space (SOLIS) large project. We present here a study of the isotopic fractionation of SiO towards L1157-B1. Furthermore, we use the high spectral resolution observations on the main isotopologue, ^28^SiO, to study the jet impact on the dense gas. We present here also single-dish observations obtained with the IRAM 30m telescope and Herschel-HIFI. We carried out a non-LTE analysis using a Large Velocity Gradient (LVG) code to model the single-dish observations. From our observations we can show that (i) the (2-1) transition of the main isotopologue is optically thick in L1157-B1 even at high velocities, and (ii) the [^29^SiO/^30^SiO] ratio is constant across the source, and consistent with the solar value of 1.5. We report the first isotopic fractionation maps of SiO in a shocked region and show the absence of a mass dependent fractionation in ^29^Si and ^30^Si across L1157-B1. A high-velocity bullet in ^28^SiO has been identified, showing the signature of a jet impacting on the dense gas. With the dataset presented in this paper, both interferometric and single-dish, we were able to study in great detail the gas shocked at the B1a position and its surrounding gas.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A136
- Title:
- Sources detected at 325 and 610 MHz in Cygnus
- Short Name:
- J/A+A/642/A136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations at the radio continuum band below the gigahertz band are key when the nature and properties of non-thermal sources are investigated because their radio radiation is strongest at these frequencies. The low radio frequency range is therefore the best to spot possible counterparts to very high-energy (VHE) sources: relativistic particles of the same population are likely to be involved in radio and high-energy radiation processes. Some of these counterparts to VHE sources can be stellar sources. The Cygnus region in the northern sky is one of the richest in this type of sources that are potential counterparts to VHEsources. We surveyed the central ~15 sq deg of the Cygnus constellation at the 325 and 610MHz bands with angular resolutions and sensitivities of 10" and 6", and 0.5 and 0.2mJy/beam, respectively. The data were collected during 172 hours in 2013-2017, using the Giant Metrewave Radio Telescope (GMRT) with 32MHz bandwidth, and were calibrated using the SPAM routines. The source extraction was carried out with the PyBDSF tool,followed by verification through visual inspection of every putative catalog candidate source in order to determine its reliability. In this first paper we present the catalog of sources, consisting of 1048 sources at 325MHz and 2796 sources at 610MHz. By cross-matching the sources from both frequencies with the objects of the SIMBAD database, we found possible counterparts for 143 of them. Most of the sources from the 325MHz catalog (993) were detected at the 610MHz band, and their spectral index alpha was computed adopting S(nu){prop.to}nu^alpha^. The maximum of the spectral index distribution is at alpha=-1, which is characteristic of non-thermal emitters and might indicate an extragalactic population.
