- ID:
- ivo://CDS.VizieR/J/A+AS/80/215
- Title:
- Lunar occultations of weak radio sources
- Short Name:
- J/A+AS/80/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains the results of lunar occultation observations of 106 radio sources within declination +/- 19 degrees at 327 MHz. There are 171 sources listed in the catalog due to multiple components for some of the radio sources. Flux densities were measured at 327 MHz by lunar occultation with the Ooty Telescope. Flux densities have also been measured at 18 cm (1669 MHz) and 21 cm (1413 MHz) using the Nancay telescope. Optical identifications on the basis of the radio positions and angular structures are given. This catalog is a merge of table 1 and table 2 from the publication.
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- ID:
- ivo://CDS.VizieR/J/A+A/630/A77
- Title:
- Lyra system LoFAR and XMM images
- Short Name:
- J/A+A/630/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Diffuse radio emission associated with the intra-cluster medium (ICM) is observed in a number of merging galaxy clusters. It is currently believed that in mergers a fraction of the kinetic energy is channeled into non-thermal components, such as turbulence, cosmic rays and magnetic fields, that may lead to the formation of giant synchrotron sources in the ICM. Studying merging galaxy clusters in different evolutionary phases is fundamental to understanding the origin of radio emission in the ICM. We observed the nearby galaxy cluster pair RXC J1825.3+3026 (z~0.065) and CIZA J1824.1+3029 (z~0.071) at 120-168MHz with the LOw Frequency ARray (LOFAR) and made use of a deep (240 ks) XMM-Newton dataset to study the nonthermal and thermal properties of the system. RXC J1825.3+3026 is in a complex dynamical state, with a primary on-going merger in the E-W direction and a secondary later stage merger with a group of galaxies in the SW, while CIZA J1824.1+3029 is dynamically relaxed. These two clusters are in a pre-merger phase. We report the discovery of a Mpc-scale radio halo with a low surface brightness extension in RXC J1825.3+3026 that follows the X-ray emission from the cluster center to the remnant of a galaxy group in the SW. This is among the least massive systems and the faintest giant radio halo known to date. Contrary to this, no diffuse radio emission is observed in CIZA J1824.1+3029 nor in the region between the pre-merger cluster pair. The power spectra of the X-ray surface brightness fluctuations of RXC J1825.3+3026 and CIZA J1824.1+3029 are in agreement with the findings for clusters exhibiting a radio halo and the ones where no radio emission has been detected, respectively. We provide quantitative support to the idea that cluster mergers play a crucial role in the generation of non-thermal components in the ICM.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A2
- Title:
- MACS J0717.5+3745 polarization int. maps
- Short Name:
- J/A+A/657/A2
- Date:
- 21 Mar 2022 09:20:37
- Publisher:
- CDS
- Description:
- We present wideband (1-6.5 GHz) polarimetric observations, obtained with the Karl G. Jansky Very Large Array (VLA), of the merging galaxy cluster MACS J0717.5+3745, which hosts one of the most complex known radio relic and halo systems. We use both Rotation Measure Synthesis and QU-fitting, and find a reasonable agreement of the results obtained with these methods, in particular, when the Faraday distribution is simple and the depolarization is mild. The relic is highly polarized over its entire length (850kpc), reaching a fractional polarization >30% in some regions. We also observe a strong wavelength-dependent depolarization for some regions of the relic. The northern part of the relic shows a complex Faraday distribution suggesting that this region is located in or behind the intracluster medium (ICM). Conversely, the southern part of the relic shows a Rotation Measure very close to the Galactic foreground, with a rather low Faraday dispersion, indicating very little magnetoionic material intervening the line-of-sight. From spatially resolved polarization analysis, we find that the scatter of Faraday depths correlates with the depolarization, indicating that the tangled magnetic field in the ICM causes the depolarization. We conclude that the ICM magnetic field could be highly turbulent. At the position of a well known narrow-angle-tailed galaxy (NAT), we find evidence of two components clearly separated in Faraday space. The high Faraday dispersion component seems to be associated with the NAT, suggesting the NAT is embedded in the ICM while the southern part of the relic lies in front of it. If true, this implies that the relic and this radio galaxy are not necessarily physically connected and thus, the relic may be not powered by the shock re-acceleration of fossil electrons from the NAT. The magnetic field orientation follows the relic structure indicating a well-ordered magnetic field. We also detect polarized emission in the halo region; however the absence of significant Faraday rotation and a low value of Faraday dispersion suggests the polarized emission, previously considered as the part of the halo, has a shock(s) origin.
- ID:
- ivo://CDS.VizieR/J/A+A/657/A1
- Title:
- Maggie filament datacubes
- Short Name:
- J/A+A/657/A1
- Date:
- 21 Mar 2022 09:19:29
- Publisher:
- CDS
- Description:
- The atomic phase of the interstellar medium plays a key role in the formation process of molecular clouds. Due to the line-of-sight confusion in the Galactic plane that is associated with its ubiquity, atomic hydrogen emission has been challenging to study. We investigate the physical properties of the "Maggie" filament, a large-scale filament identified in HI emission at line-of-sight velocities, v_LSR_~-54km/s. Employing the high-angular resolution data from The HI/OH Recombination line survey of the inner Milky Way (THOR), we have been able to study HI emission features at negative v_LSR_ velocities without any line-of-sight confusion due to the kinematic distance ambiguity in the first Galactic quadrant. In order to investigate the kinematic structure, we decomposed the emission spectra using the automated Gaussian fitting algorithm GaussPy+. We identify one of the largest, coherent, mostly atomic HI filaments in the Milky Way. The giant atomic filament Maggie, with a total length of 1.2+/-0.1kpc, is not detected in most other tracers, and it does not show signs of active star formation. At a kinematic distance of 17kpc, Maggie is situated below (by ~500pc), but parallel to, the Galactic HI disk and is trailing the predicted location of the Outer Arm by 5-10km/s in longitude-velocity space. The centroid velocity exhibits a smooth gradient of less than 3(km/s)/(10pc) and a coherent structure to within +/-6km/s. The line widths of ~10km/s along the spine of the filament are dominated by nonthermal effects. After correcting for optical depth effects, the mass of Maggie's dense spine is estimated to be 7.2x10^5^ solar masses. The mean number density of the filament is ~4cm^-3^, which is best explained by the filament being a mix of cold and warm neutral gas. In contrast to molecular filaments, the turbulent Mach number and velocity structure function suggest that Maggie is driven by transonic to moderately supersonic velocities that are likely associated with the Galactic potential rather than being subject to the effects of self-gravity or stellar feedback. The probability density function of the column density displays a log-normal shape around a mean of 4.8x10^20^cm^-2^, thus reflecting the absence of dominating effects of gravitational contraction.
- ID:
- ivo://CDS.VizieR/J/ApJ/688/1029
- Title:
- Magnetic field in the SMC
- Short Name:
- J/ApJ/688/1029
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a study of the magnetic field of the Small Magellanic Cloud (SMC), carried out using radio Faraday rotation and optical starlight polarization data. Consistent negative rotation measures (RMs) across the SMC indicate that the line-of-sight magnetic field is directed uniformly away from us with a strength 0.19+/-0.06{mu}G. Applying the Chandrasekhar-Fermi method to starlight polarization data yields an ordered magnetic field in the plane of the sky of strength 1.6+/-0.4uG oriented at a position angle 4+/-12{deg}, measured counterclockwise from the great circle on the sky joining the SMC to the Large Magellanic Cloud (LMC). We construct a three-dimensional magnetic field model of the SMC, under the assumption that the RMs and starlight polarization probe the same underlying large-scale field. further test the pan-Magellanic field hypothesis.
- ID:
- ivo://CDS.VizieR/J/AZh/94/598
- Title:
- Magnetic fields of radio pulsars
- Short Name:
- J/AZh/94/598
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The mechanism of magnetodipole braking of radio pulsars is used to calculate new values of the surface magnetic fields of neutron stars. The angles {beta} between the spin axes and magnetic moments of the neutron stars were estimated for 376 radio pulsars using three different methods. It is shown that small inclinations of magnetic axes dominate. The equatorial magnetic fields for the considered sample of pulsars are calculated using the {beta} values obtained. As a rule, these magnetic fields are a factor of a few higher than the corresponding values in known catalogs.
- ID:
- ivo://CDS.VizieR/J/A+A/385/1014
- Title:
- Magnetic field structure in W51A
- Short Name:
- J/A+A/385/1014
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 850{mu}m imaging polarimetry of the W51A massive star forming region performed with SCUBA on the James Clerk Maxwell Telescope (JCMT) situated close to the summit of Mauna Kea, Hawaii, on the night 6 October 2000. Positions, fluxes and polarimetry of the data points shown in Fig. 1 of the paper are reported in the file table2.dat. The positional offsets are given relative to W51d (19:23:39.0, +14:31:08, J2000). All fluxes (including the Stokes Q and U parameters) are given in units of Jy/beam. The position angles give the direction of the E-vector.
808. MAGPIS 20cm survey
- ID:
- ivo://CDS.VizieR/J/AJ/131/2525
- Title:
- MAGPIS 20cm survey
- Short Name:
- J/AJ/131/2525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Multi-Array Galactic Plane Imaging Survey (MAGPIS), which maps portions of the first Galactic quadrant with an angular resolution, sensitivity, and dynamic range that surpass existing radio images of the Milky Way by more than an order of magnitude. The source detection threshold at 20cm is in the range 12mJy over the 85% of the survey region (5{deg}<l<32{deg}, |b|<0.8{deg}) not covered by bright extended emission; the angular resolution is ~6". We catalog over 3000 discrete sources (diameters mostly <30") and present an atlas of ~400 diffuse emission regions. New and archival data at 90cm for the whole survey area are also presented. Comparison of our catalogs and images with the Midcourse Space Experiment mid-infrared data allows us to provide preliminary discrimination between thermal and nonthermal sources. We identify 49 high-probability supernova remnant candidates, increasing by a factor of 7 the number of known remnants with diameters smaller than 5' in the survey region; several are pulsar wind nebula candidates and/or very small diameter remnants (D<45").
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2344
- Title:
- MALT-45, a 7mm survey of the southern Galaxy
- Short Name:
- J/MNRAS/448/2344
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first results from the MALT-45 (Millimetre Astronomer's Legacy Team-45GHz) Galactic Plane survey. We have observed 5 square degrees (l=330{deg}-335{deg}, b=+/-0.5{deg}) for spectral lines in the 7mm band (42-44 and 48-49GHz), including CS (1-0), class I CH_3_OH masers in the 7(0,7)-6(1,6) A^+^ transition and SiO (1-0) v=0,1,2,3. MALT-45 is the first unbiased, large-scale, sensitive spectral line survey in this frequency range. In this paper, we present data from the survey as well as a few intriguing results; rigorous analyses of these science cases are reserved for future publications. Across the survey region, we detected 77 class I CH_3_OH masers, of which 58 are new detections, along with many sites of thermal and maser SiO emission and thermal CS. We found that 35 class I CH_3_OH masers were associated with the published locations of class II CH_3_OH, H_2_O and OH masers but 42 have no known masers within 60 arcsec. We compared the MALT-45 CS with NH_3_ (1,1) to reveal regions of CS depletion and high opacity, as well as evolved star-forming regions with a high ratio of CS to NH_3_. All SiO masers are new detections, and appear to be associated with evolved stars from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). Generally, within SiO regions of multiple vibrational modes, the intensity decreases as v=1, 2, 3, but there are a few exceptions where v=2 is stronger than v=1.
- ID:
- ivo://CDS.VizieR/J/MNRAS/471/3915
- Title:
- MALT-45, 44 GHz class I methanol masers
- Short Name:
- J/MNRAS/471/3915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We detail interferometric observations of 44GHz class I methanol masers detected by MALT-45 (a 7mm unbiased auto-correlated spectral-line Galactic-plane survey) using the Australia Telescope Compact Array. We detect 238 maser spots across 77 maser sites. Using high-resolution positions, we compare the class I CH_3_OH masers to other star formation maser species, including CS (1-0), SiO v=0 and the H53{alpha} radio-recombination line. Comparison between the cross- and auto-correlated data has allowed us to also identify quasi-thermal emission in the 44GHz class I methanol maser line. We find that the majority of class I methanol masers have small spatial and velocity ranges (<0.5pc and <5km/s), and closely trace the systemic velocities of associated clouds. Using 870{mu}m dust continuum emission from the ATLASGAL survey, we determine clump masses associated with class I masers, and find that they are generally associated with clumps between 1000 and 3000M_{sun}_. For each class I methanol maser site, we use the presence of OH masers and radio recombination lines to identify relatively evolved regions of high-mass star formation; we find that maser sites without these associations have lower luminosities and preferentially appear towards dark infrared regions.