- ID:
- ivo://CDS.VizieR/VIII/2
- Title:
- Molonglo Reference Catalog of Radio Sources
- Short Name:
- VIII/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Molonglo Reference Catalog of Radio Sources results from a 408-MHz survey observations made with the Molonglo Radio Telescope (Australia) between 1968 and 1978. The survey covers 7.85sr of the sky between the declinations -85{deg} and +18{deg}, excluding the strip of the galactic plane (|b|<=3{deg}). The nominal beamwidth is 2.62arcmin in right ascension and 2.86sec({delta}+35.5)arcmin in declination. There are 7347 sources with flux density S>=1Jy, at which level the catalogue is substantially complete. A new version of the catalog has been done in 1990 (Cat. VIII/16).
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- ID:
- ivo://CDS.VizieR/VIII/16
- Title:
- Molonglo Reference Catalogue of Radio Sources
- Short Name:
- VIII/16
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- "408-MHz survey observations made with the Molonglo Radio Telescope have been used to prepare a catalogue of 12 141 discrete sources of listed flux density >= 0.7 Jy. The survey covers 7.85 sr of the sky defined by +18.5 (deg) >= dec(1950) >= -85.0 (deg), mod(b) >= 3 (deg). A few sources beyond the declination limits are also included. The catalogue comprises celestial coordinates with standard error typically lying between 3 and 10 arcsec and 408-MHz flux densities with standard error typically lying between 4 and 10 per cent. Galactic coordinates, notes on source morphology and cross-references to the Parkes Catalogues are included. The overall source density is 1500/sr, corresponding to 0.001 per beam area. There are 7347 sources of listed flux density >= 1.00 Jy, at which level the catalogue is substantially complete. The reliability is believed to be better than 99.9 per cent." The MRC was re-issued in 1990 with the original B1950 coordinates supplemented by J2000 values, and an additional cross-reference flag `J' added to denote (extended) sources imaged at 843-MHz by P.A. Jones. No other alterations were made to the original release. The MRC is now available on 5.25 inch, 1.2 Mbyte MS-DOS (IBM) floppy disk (0.5 inch magnetic tape is also available, but is not the preferred medium). In the floppy disk format, simple software is provided to facilitate use of the catalogue on a PC computer.
- ID:
- ivo://CDS.VizieR/J/ApJS/136/265
- Title:
- Monitoring compact radio sources at 2.5 + 8.2GHz
- Short Name:
- J/ApJS/136/265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present light curves for 149 sources monitored with the Green Bank Interferometer. The light curves are at two radio frequencies (approximately 2.5 and 8.2GHz) and range from 3 to 15yr in length, covering the interval 1979-1996, and have a typical sampling of one flux density measurement every 2 days. Observations were made on a 2.4km baseline. Dual circular polarization was recorded over a 35MHz bandwidth at two frequencies in the S and X frequency bands. Until 1989 August (1989.7), the frequencies were 2.7GHz (S band) and 8.1GHz (X band); in 1989 September cryogenic receivers were installed, and the frequencies changed to 2.25GHz (S band) and 8.3GHz (X band).
- ID:
- ivo://CDS.VizieR/J/A+A/545/A117
- Title:
- Monitoring of Mrk 421 at 15 and 24 GHz
- Short Name:
- J/A+A/545/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution radio observations are ideal for constraining the value of physical parameters in the inner regions of active-galactic-nucleus jets and complement results on multiwavelength (MWL) observations. This study is part of a wider multifrequency campaign targeting the nearby TeV blazar Markarian 421 (z=0.031), with observations in the sub-mm (SMA), optical/IR (GASP), UV/X-ray (Swift, RXTE, MAXI), and {gamma} rays (Fermi-LAT, MAGIC, VERITAS). We investigate the jet's morphology and any proper motions, and the time evolution of physical parameters such as flux densities and spectral index. The aim of our wider multifrequency campaign is to try to shed light on questions such as the nature of the radiating particles, the connection between the radio and {gamma}-ray emission, the location of the emitting regions and the origin of the flux variability.
- ID:
- ivo://CDS.VizieR/J/AJ/140/533
- Title:
- Morphologies of selected AGN
- Short Name:
- J/AJ/140/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the optical morphologies of candidate active galaxies identified at radio, X-ray, and mid-infrared wavelengths. We use the Advanced Camera for Surveys General Catalog (ACS-GC) to identify 372, 1360, and 1238 active galactic nucleus (AGN) host galaxies from Very Large Array, XMM-Newton, and Spitzer Space Telescope observations of the COSMOS field, respectively. We investigate both quantitative (GALFIT) and qualitative (visual) morphologies of these AGN host galaxies, split by brightness in their selection band.
- ID:
- ivo://CDS.VizieR/J/ApJS/194/31
- Title:
- Morphology for groups in the FIRST database
- Short Name:
- J/ApJS/194/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The morphology of selected groups of sources in the Faint Images of the Radio Sky at Twenty Centimeters (FIRST) survey and catalog is examined. Sources in the FIRST catalog (2003 April release, 811117 entries) were sorted into singles, doubles, triples, and groups of higher-count membership based on a proximity criteria. The 7106 groups with four or more components were examined individually for bent types including, but not limited to, wide-angle tail and narrow-angle tail types. In the process of this examination, ring, double-double, X-shaped, hybrid morphology, giant radio sources, and the herein described W-shaped and tri-axial morphology systems were also identified. For the convenience of the reader separate tables for distinctive types were generated. A few curiosities were found. For the 16950 three-component groups and 74788 two-component groups, catalogs with probability estimates for bent classification, as determined by pattern recognition techniques, are presented.
- ID:
- ivo://CDS.VizieR/J/A+AS/118/329
- Title:
- MOST supernova remnant catalogue (MSC)
- Short Name:
- J/A+AS/118/329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of supernova remnants in the southern Galaxy within the area 245{deg}<=l<=355{deg}, |b|<~1.5{deg} has been produced from observations made at 0.843GHz with a resolution of 43" using the Molonglo Observatory Synthesis Telescope (MOST).
- ID:
- ivo://CDS.VizieR/J/A+A/571/A61
- Title:
- M31 polarization & magnetic structure
- Short Name:
- J/A+A/571/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Andromeda Galaxy (M31) is the nearest grand-design spiral galaxy. Thus far, most studies in the radio regime concentrated on the 10kpc ring. The central region of M31 has significantly different properties than the outer parts: The star formation rate is low, and inclination and position angle are largely different from the outer disk. The existing model of the magnetic field in the radial range 6<=r<=14kpc is extended to the innermost part r<=0.5kpc to ultimately achieve a picture of the entire magnetic field in M 31. We combined observations taken with the VLA at 3.6cm and 6.2cm with data from the Effelsberg 100-m telescope to fill the missing spacings of the synthesis data. The resulting polarization maps were averaged in sectors to analyse the azimuthal behaviour of the polarized intensity (PI), rotation measure (RM), and apparent pitch angle ({phi}_obs_). We developed a simplified 3D model for the magnetic field in the central region to explain the azimuthal behaviour of the three observables. Our 3D model of a quadrupolar or dipolar dynamo field can explain the observed patterns in PI, RM, and {phi}_obs_, while a 2D configuration is not sufficient to explain the azimuthal behaviour. In addition and independent of our model, the RM pattern shows that the spiral magnetic field in the inner 0.5kpc points outward, which is opposite to that in the outer disk, and has a pitch angle of =~33{deg}, which is much larger than that of 8{deg}-19{deg} in the outer disk. The physical conditions in the central region differ significantly from those in the 10kpc ring. In addition, the orientation of this region with respect to the outer disk is completely different. The opposite magnetic field directions suggest that the central region is decoupled from the outer disk, and we propose that an independent dynamo is active in the central region.
- ID:
- ivo://CDS.VizieR/J/A+A/588/A114
- Title:
- M101 radio polarization & magnetic structure
- Short Name:
- J/A+A/588/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed total and polarized radio continuum emission from the spiral galaxy M 101 at {lambda}{lambda}6.2cm and 11.1cm with the Effelsberg telescope. The angular resolutions are 2.5' (=5.4kpc) and 4.4' (=9.5kpc), respectively. We use these data to study various emission components in M 101 and properties of the magnetic field. Separation of thermal and non-thermal emission shows that the thermal emission is closely correlated with the spiral arms, while the non-thermal emission is more smoothly distributed indicating di ff usion of cosmic ray electrons away from their places of origin. The radial distribution of both emissions has a break near R=16kpc (=7.4'), where it steepens to an exponential scale length of L=~5kpc, which is about 2.5 times smaller than at R<16kpc. The distribution of the polarized emission has a broad maximum near R=12kpc and beyond R=16kpc also decreases with L=~5kpc. It seems that near R=16kpc a major change in the structure of M 101 takes place, which also a ff ects the distributions of the strength of the random and ordered magnetic field. Beyond R=16kpc the radial scale length of both fields is about 20kpc, which implies that they decrease to about 0.3uG at R=70kpc, which is the largest optical extent. The equipartition strength of the total field ranges from nearly 10uG at R<2kpc to 4uG at R=22-24kpc. As the random field dominates in M 101 (B_ran_/B_ord_=~2.4), wavelength-independent polarization is the main polarization mechanism. We show that energetic events causing H i shells of mean diameter <625pc could partly be responsible for this. At radii <24kpc, the random magnetic field depends on the star formation rate/area, {Sigma}_SFR_, with a power-law exponent of b=0.28+/-0.02. The ordered magnetic field is generally aligned with the spiral arms with pitch angles that are about 8{deg} larger than those of HI filaments.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/1107
- Title:
- M82 radio sources flux density variations
- Short Name:
- J/MNRAS/431/1107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the results of the 2009-2010 monitoring sessions of the starburst galaxy M82, obtained with the Multi-Element Radio-Linked Interferometer Network (MERLIN) at 5GHz and e-MERLIN at 6GHz. Combining several 5GHz MERLIN epochs to form a map with 33.0{mu}Jy/bm noise level, 52 discrete sources, mostly supernova remnants and HII regions, are identified. These include three objects which were not detected in the 2002 5GHz MERLIN monitoring session: supernova SN2008iz, the transient source 43.78+59.3, and a new supernova remnant shell. Flux density variations, in the long (1981 to 2010), medium (2002 to 2010) and short (2009 to 2010) term are investigated. We find that flux densities of supernova remnants (SNRs) in M82 stay constant in most of the sample (~95 per cent), although the distributions of flux density variations show an offset from zero. This is consistent with a slight statistical reduction in flux density of the source distribution. In addition, aside from SN2008iz and the well-known variable source 41.95+57.5, two sources display tentative evidence for short- and medium-term variations over the period 2009-2010. These sources are amongst the most compact SNR in M82. These flux density variations could be due to changes in the circumstellar and interstellar medium in which the shocks travel.
