- ID:
- ivo://CDS.VizieR/J/ApJS/68/715
- Title:
- Clark Lake 30.9MHz survey
- Short Name:
- J/ApJS/68/715
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Galactic plane has been mapped at 30.9 MHz with the Clark Lake TPT telescope giving unprecedented resolution for such a low frequency. The synthetized beam is 13.0'x11.1' at the zenith. Contour maps and a source list are presented for the regions 350deg<l<59deg, 84deg<l<97deg, and 133deg<l<250deg, with |b|<2deg-3deg. The source list contains integrated flux densities and positions for 702 discrete emission regions. Sensitivity is confusion-limited and varies from ~ 5Jy/beam in the inner Galaxy to ~ 1-2Jy/beam toward the outer Galaxy.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/359/1498
- Title:
- Class I and class II methanol masers
- Short Name:
- J/MNRAS/359/1498
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Australia Telescope National Facility Mopra millimetre telescope has been used to search for 95.1-GHz class I methanol masers towards 62 6.6-GHz class II methanol masers. A total of 26 95.1-GHz masers were detected, 18 of these being new discoveries. Combining the results of this search with observations reported in the literature, a near complete sample of 66 6.6-GHz class II methanol masers has been searched in the 95.1-GHz transition, with detections towards 38 per cent (25 detections; not all of the sources studied in this paper qualify for the complete sample, and some of the sources in the sample were not observed in the present observations).
- ID:
- ivo://CDS.VizieR/VIII/72
- Title:
- CLASS survey of radio sources
- Short Name:
- VIII/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Cosmic Lens All-Sky Survey (CLASS) is an international collaborative program aimed at obtaining high-resolution radio images of over 10000 flat-spectrum radio sources in order to create the largest and best studied statistical sample of radio-loud gravitationally lensed systems. CLASS is aimed at identifying lenses where multiple images are formed from compact flat-spectrum radio sources, which should be easily identifiable in the radio maps (Browne et al., 2003MNRAS.341...13B). In four observing ``seasons'' from 1994-1999, CLASS has observed 13832 radio sources. When combined with the JVAS survey, the CLASS sample contains over 16,000 images. Using the GB6 and NVSS surveys, a complete statistical subset of 11685 sources has been constructed. These were selected from the NVSS 20-cm (Condon et al., 1998, Cat. <VIII/65>) and GB6 6-cm (Gregory et al., 1996, Cat. <VIII/40>) catalogues by the selection criteria: declination >0deg, |b|<10deg, S(6cm)>=30mJy, and spectral index between 6 and 20cm flatter than -0.5 (S proportional to frequency^+alpha^). The remaining sources were selected using earlier versions of these catalogues or with slightly relaxed versions of these criteria.
- ID:
- ivo://CDS.VizieR/J/A+A/656/A154
- Title:
- ClG 0217+70 radio images
- Short Name:
- J/A+A/656/A154
- Date:
- 21 Mar 2022 09:15:55
- Publisher:
- CDS
- Description:
- Megaparsec-scale radio sources in the form of halos and relics are often detected in dynamically disturbed galaxy clusters. Although they are associated with merger-induced turbulence and shocks, respectively, their formation is not fully understood. Aims. We aim to identify the mechanisms responsible for particle acceleration and magnetic field amplification in the halo and relics of the galaxy cluster ClG 0217+70. We observed ClG 0217+70 with LOFAR at 141MHz and with VLA at 1.5GHz, and we combined these observations with VLA 1.4GHz archival data to study the morphological and spectral properties of the diffuse sources.We added Chandra archival data to examine the thermal and non-thermal properties of the halo. Our LOFAR and VLA data confirm the presence of a giant radio halo in the cluster centre and multiple relics in the outskirts. The radio and X-ray emission from the halo are correlated, implying a tight relation between the thermal and non-thermal components. The diuse radio structure in the south-east, with a projected size of 3.5Mpc, is the most extended radio relic detected to date. The spectral index across the relic width steepens towards the cluster centre, suggesting electron ageing in the post-shock regions. The shock Mach numbers for the relics derived from the spectral index map range between 2.0 and 3.2. However, the integrated spectral indices lead to increasingly high Mach numbers for the relics farther from the cluster centre. This discrepancy could be because the relation between injection and integrated spectra does not hold for distant shocks, suggesting that the cooling time for the radioemitting electrons is longer than the crossing time of the shocks. The variations in the surface brightness of the relics and the low Mach numbers imply that the radio-emitting electrons are re-accelerated from fossil plasma that could originate in active galactic nuclei.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A10
- Title:
- 3C295 LOFAR, MERLIN and VLA images
- Short Name:
- J/A+A/658/A10
- Date:
- 02 Feb 2022 13:43:44
- Publisher:
- CDS
- Description:
- 3C295 is a bright, compact steep spectrum source with a well-studied integrated radio spectral energy distribution (SED) from 132MHz to 15GHz. However, spatially resolved spectral studies have been limited due to a lack of high resolution images at low radio frequencies. These frequencies are crucial for measuring absorption processes, and anchoring the overall spectral modelling of the radio SED. In this paper, we use International LOw-Frequency ARray (LOFAR) Telescope (ILT) observations of 3C295 to study its spatially resolved spectral properties with sub-arcsecond resolution at 132MHz. Combining our new 132MHz observation with archival data at 1.6GHz, 4.8GHz, and 15GHz, we are able to carryout a resolved radio spectral analysis. The spectral properties of the hotspots provides evidence for low frequency flattening. In contrast, the spectral shape across the lobes is consistent with a Jaffe-Perola spectral ageing model. Usingthe integrated spectral information for each component, we then fitted low-frequency absorption models to the hotspots,finding that both free-free absorption and synchrotron self-absorption models provide a better fit to the data than a standard power law. Although we can say there is low-frequency absorption present in the hot spots of 3C295, future observations with the Low Band Antenna of the ILT at 55MHz may allow us to distinguish the type of absorption.
- 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/other/Ser/184.93
- Title:
- 6cm and 3cm sources in SMC
- Short Name:
- J/other/Ser/184.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present two new catalogues of radio-continuum sources in the field of the Small Magellanic Cloud (SMC). These catalogues contain sources found at 4800MHz (λ=6cm) and 8640MHz (λ=3cm). Some 457 sources have been detected at 3cm with 601 sources at 6cm created from new high-sensitivity and resolution radio-continuum images of the SMC from Crawford et al. (<A HREF="http://simbad.cds.unistra.fr/simbad/sim-ref?bibcode=2011SerAJ.183...95C%202011SerAJ.183...95C">2011SerAJ.183...95C 2011SerAJ.183...95C</A>).
- ID:
- ivo://CDS.VizieR/J/ApJS/177/515
- Title:
- 6cm and 20cm survey of Galactic Center
- Short Name:
- J/ApJS/177/515
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the results of a millijansky sensitivity VLA survey of roughly 1deg^2^ near the Galactic center at 6 and 20cm. Catalogs of compact and filamentary structures are given and compared to previous surveys of the region. Eight of the unusual nonthermal radio filaments are detected in 6cm polarized emission; three of these are the first such detections, confirming their nonthermal nature. This survey found emission from a filament at (l,b)=(359.1,0.75), or a projected distance from Sgr A* of 200pc, greatly extending the latitude range observed with such features. There is also new evidence for spatial gradients in the 6/20cm spectral indices of some filaments, and we discuss models for these gradients. In studying compact sources, the combination of spectral index and polarization information allows us to identify pulsar candidates and compact HII regions in the survey. There is also some evidence that the flux measurements of compact sources may be affected by electron scattering from the interstellar medium in the central few hundred parsecs of the Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJS/227/25
- Title:
- 6 & 1.3cm deep VLA obs. toward 58 high-mass SFRs
- Short Name:
- J/ApJS/227/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a high-sensitivity radio continuum survey at 6 and 1.3cm using the Karl G. Jansky Very Large Array toward a sample of 58 high-mass star-forming regions. Our sample was chosen from dust clumps within infrared dark clouds with and without IR sources (CMC-IRs and CMCs, respectively), and hot molecular cores (HMCs), with no previous, or relatively weak radio continuum detection at the 1mJy level. Due to the improvement in the continuum sensitivity of the Very Large Array, this survey achieved map rms levels of ~3-10{mu}Jy/beam at sub-arcsecond angular resolution. We extracted 70 continuum sources associated with 1.2mm dust clumps. Most sources are weak, compact, and prime candidates for high-mass protostars. Detection rates of radio sources associated with the millimeter dust clumps for CMCs, CMC-IRs, and HMCs are 6%, 53%, and 100%, respectively. This result is consistent with increasing high-mass star formation activity from CMCs to HMCs. The radio sources located within HMCs and CMC-IRs occur close to the dust clump centers, with a median offset from it of 12000au and 4000au, respectively. We calculated 5-25GHz spectral indices using power-law fits and obtained a median value of 0.5 (i.e., flux increasing with frequency), suggestive of thermal emission from ionized jets. In this paper we describe the sample, observations, and detections.
