- ID:
- ivo://CDS.VizieR/J/A+A/578/A93
- Title:
- IC 342 multi-frequency radio polarization study
- Short Name:
- J/A+A/578/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic fields play an important role in the formation and stabilization of spiral structures in galaxies, but the interaction between interstellar gas and magnetic fields has not yet been understood. In particular, the phenomenon of "magnetic arms" located between material arms is a mystery. The strength and structure of interstellar magnetic fields and their relation to spiral arms in gas and dust are investigated in the nearby and almost face-on spiral galaxy IC 342.
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- ID:
- ivo://CDS.VizieR/J/ApJ/873/132
- Title:
- ICRF3 radio-loud quasars with Gaia DR2 data
- Short Name:
- J/ApJ/873/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate a sample of 3413 International Celestial Reference Frame (ICRF3) extragalactic radio-loud sources with accurate positions determined by very long baseline interferometry in the S/X band, mostly active galactic nuclei and quasars, which are cross-matched with optical sources in the second Gaia data release (Gaia DR2). The main goal of this study is to determine a core sample of astrometric objects that define the mutual orientation of the two fundamental reference frames, the Gaia (optical) and the ICRF3 (radio) frames. The distribution of normalized offsets between the VLBI sources and their optical counterparts is non-Rayleigh, with a deficit around the modal value and a tail extending beyond the 3{sigma} confidence level. A few filters are applied to the sample in order to discard double cross-matches, confusion sources, and Gaia astrometric solutions of doubtful quality. Panoramic Survey Telescope and Rapid Response System and Dark Energy Survey stacked multicolor images are used to further deselect objects that are less suitable for precision astrometry, such as extended galaxies, double and multiple sources, and obvious misidentifications. After this cleaning, 2643 quasars remain, of which 20% still have normalized offset magnitudes exceeding 3, or a 99% confidence level. We publish a list of 2119 radio-loud quasars of prime astrometric quality. The observed dependence of binned median offset on redshift shows the expected decline at small redshifts, but also an unexpected rise at z~1.6, which may be attributed to the emergence of the CIV emission line in the Gaia's G band. The Gaia DR2 parallax zero-point is found to be color-dependent, suggesting an uncorrected instrumental calibration effect.
- ID:
- ivo://CDS.VizieR/J/other/KFNT/27.299
- Title:
- ICRF stars near extragalactic radio sources
- Short Name:
- J/other/KFNT/27.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The compiled catalogue of 231044 stars was created from photographic and CCD observations of position catalogues observed by ground based telescopes. The catalogue destine for optical observations VLBI-ICRS astrometrical extragalactic radiosources (ERS) with telescopes equiped with CCD-cameras. The main purpose of this catalogue is to ensure the reference stars in optics for reducing positions of faint astrometrical ERS 17-22mag relative to more bright reference stars 14-17mag. The catalogue contains 231044 star positions in fields 40'x40' near 240 ERS. More than nine catalogues of stars coordinates were used for compiling the Pul-ERS catalogue. For 69% of stars the proper motions were taken from UCAC3 catalogue to convert the position stars to the common epoch. The number of position measurements for each star varies from one to more than ten records. The inner precision of positions of stars in Pul-ERS is from 4 to 150mas. 159331 stars of the compiled catalogue were identified with stars of the UCAC3. The average internal accuracy of positions on both coordinates is not worse 0.11".
- ID:
- ivo://CDS.VizieR/J/ApJ/615/702
- Title:
- IC 133 water vapor maser
- Short Name:
- J/ApJ/615/702
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the results of a 14yr long VLBI study of proper motions in the IC 133 H_2_O maser source in the galaxy M33.
- ID:
- ivo://CDS.VizieR/J/PAZh/25/447
- Title:
- Identification of radio sources. I.
- Short Name:
- J/PAZh/25/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed identification of radio sources within the Abell radii in 26 rich galactic clusters of the FIRST catalog with optical objects of the APM and DSS surveys had been carried out. Of the 326 radio sources in the cluster fields, 99 are identified, 40 have probable identifications, and 187 are unidentified. Among last sources, 20 are definitely located in the clusters and 34 are cluster members with high probability. Thus, 30-40% of the FIRST radio sources could be identified using APM and DSS data, and there were two sources in each cluster on the average.
- ID:
- ivo://CDS.VizieR/J/AZh/73/835
- Title:
- Identifications of objects from RC Catalog
- Short Name:
- J/AZh/73/835
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Results from a continuing program for identification of sources from the RC catalog (from observations with the RATAN-600 radio telescope) with the APM (Automatic Plate Measuring) Northern Sky Catalogs available via the Internet are presented. The coordinate accuracy for the optical objects is better than 1".
- ID:
- ivo://CDS.VizieR/J/A+A/562/A70
- Title:
- Imaging GRB 980425 in millimetic and submm
- Short Name:
- J/A+A/562/A70
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gamma-ray bursts (GRBs) have been proposed as a tool to study star formation in the Universe, so it is crucial to investigate whether their host galaxies and immediate environments are in any way special compared with other star-forming galaxies. Here we present spatially resolved maps of dust emission of the host galaxy of the closest known GRB 980425 at z=0.0085 using our new high-resolution observations from Herschel, APEX, ALMA and ATCA. We modeled the spectral energy distributions of the host and of the star-forming region displaying the Wolf-Rayet signatures in the spectrum (WR region), located 800pc away from the GRB position. The host is characterised by low dust content and high fraction of UV-visible star-formation, similar to other dwarf galaxies. Such galaxies are abundant in the local universe, so it is not surprising to find a GRB in one of them, assuming the correspondence between the GRB rate and star-formation. The WR region contributes substantially to the host emission at the far-infrared, millimeter and radio wavelengths and we propose this to be a consequence of its high gas density. If dense environments are also found close to the positions of other GRBs, then the ISM density should also be considered as an important factor influencing whether a given stellar population can produce a GRB, in a similar way as metallicity.
- ID:
- ivo://CDS.VizieR/J/MNRAS/461/2288
- Title:
- Infall motions in massive star-forming regions
- Short Name:
- J/MNRAS/461/2288
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we aim to characterize high-mass clumps with infall motions. We selected 327 clumps from the Millimetre Astronomy Legacy Team 90-GHz survey, and identified 100 infall candidates. Combined with the results of He et al. (2015, Cat. J/MNRAS/450/1926), we obtained a sample of 732 high-mass clumps, including 231 massive infall candidates and 501 clumps where infall is not detected. Objects in our sample were classified as pre-stellar, proto-stellar, HII or photodissociation region (PDR). The detection rates of the infall candidates in the pre-stellar, proto-stellar, HII and PDR stages are 41.2 per cent, 36.6 per cent, 30.6 per cent and 12.7 per cent, respectively. The infall candidates have a higher H_2_ column density and volume density compared with the clumps where infall is not detected at every stage. For the infall candidates, the median values of the infall rates at the pre-stellar, proto-stellar, HII and PDR stages are 2.6 x 10^-3^, 7.0x10^-3^, 6.5x10^-3^ and 5.5x10^-3^M_{sun}_/yr, respectively. These values indicate that infall candidates at later evolutionary stages are still accumulating material efficiently. It is interesting to find that both infall candidates and clumps where infall is not detected show a clear trend of increasing mass from the pre-stellar to proto-stellar, and to the HII stages. The power indices of the clump mass function are 2.04+/-0.16 and 2.17+/-0.31 for the infall candidates and clumps where infall is not detected, respectively, which agree well with the power index of the stellar initial mass function (2.35) and the cold Planck cores (2.0).
- ID:
- ivo://CDS.VizieR/J/MNRAS/450/1926
- Title:
- Infall motions in massive star-forming regions
- Short Name:
- J/MNRAS/450/1926
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive star-forming regions with observed infall motions are good sites for studying the birth of massive stars. In this paper, 405 compact sources have been extracted from the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL) compact sources that also have been observed in the Millimetre Astronomy Legacy Team 90-GHz (MALT90) survey during years 1 and 2. These observations are complemented with Spitzer GLIMPSE/MIPSGAL mid-IR survey data to help classify the elected star-forming clumps into three evolutionary stages: pre-stellar, proto-stellar and UCHII regions. The results suggest that 0.05g/cm^2^ is a reliable empirical lower bound for the clump surface densities required for massive-star formation to occur. The optically thick HCO^+^(1-0) and HNC(1-0) lines, as well as the optically thin N_2_H^+^(1-0) line were used to search for infall motions towards these sources. By analysing the asymmetries of the optically thick HCO^+^(1-0) and HNC(1-0) lines and the mapping observations of HCO^+^(1-0), a total of 131 reliable infall candidates have been identified. The HCO^+^(1-0) line shows the highest occurrence of obvious asymmetric features, suggesting that it may be a better infall motion tracer than other lines such as HNC(1-0). The detection rates of infall candidates towards pre-stellar, proto-stellar and UCHII clumps are 0.3452, 0.3861 and 0.2152, respectively. The relatively high detection rate of infall candidates towards UCHII clumps indicates that many UCHII regions are still accreting matter. The peak column densities and masses of the infall candidates, in general, display an increasing trend with progressing evolutionary stages. However, the rough estimates of the mass infall rate show no obvious variation with evolutionary stage.
- ID:
- ivo://CDS.VizieR/J/ApJS/95/535
- Title:
- Infrared CO line list for X 1{Sigma}+ state
- Short Name:
- J/ApJS/95/535
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A complete line list with improved accuracy for all the rotation- vibration transitions of the fundamental, first, and second overtone bands up to nu=20 and J=149 of the ground state X ^1^{Sigma}^+^ of the seven CO isotopes - 12C16O, 13C16O, 12C17O, 12C18O, 13C18O, 14C16O, and 13C17O - is made available to the astronomical community. A line list of the pure rotational transitions up to nu=5 and J=60 is also made available for these seven isotopes. This line list contains the transition frequency, the lower state energy, the Einstein A-value, the gf-value, the transition strength at 3000K or 1000K for the pure rotational transitions, the expectation value of the effective dipole moment operator, and the quantum numbers of each transition. Individual partition functions are reported in the temperature range of 500 to 10,000K.
