- ID:
- ivo://CDS.VizieR/J/MNRAS/414/2528
- Title:
- LBA Calibrator Survey (LCS1)
- Short Name:
- J/MNRAS/414/2528
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of accurate positions and correlated flux densities for 410 flat-spectrum, compact extragalactic radio sources previously detected in the AT20G survey. The catalogue spans the declination range [-90{deg}, -40{deg}] and was constructed from four 24-hour VLBI observing sessions with the Australian Long Baseline Array at 8.3GHz. The VLBI detection rate in these experiments is 97%, the median uncertainty of the source positions is 2.6mas, and the median correlated flux density on projected baselines longer than 1000km is 0.14Jy. The goals of this work are 1) to provide a pool of southern sources with positions accurate to a few milliarcsec, which can be used for phase referencing observations, geodetic VLBI and space navigation; 2) to extend the complete flux-limited sample of compact extragalactic sources to the southern hemisphere; and 3) to investigate the parsec-scale properties of high-frequency selected sources from the AT20G survey. As a result of this VLBI campaign, the number of compact radio sources south of declination -40 deg which have measured VLBI correlated flux densities and positions known to milliarcsec accuracy has increased by a factor of 3.5. The catalogue and supporting material is available at http://astrogeo.org/lcs1.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/AstBu/74.66
- Title:
- Main sequence magnetic stars properties
- Short Name:
- J/other/AstBu/74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We reconsidered the previous studies of properties of magnetic stars based on the latest data on average surface magnetic fields of 177 stars. New, corrected results have been obtained that allow a better understanding of the phenomenon of magnetic chemically peculiar stars.
- ID:
- ivo://CDS.VizieR/I/272
- Title:
- M2000: Bordeaux Carte du Ciel zone +11<Dec<+18
- Short Name:
- I/272
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During four years, systematic observations have been conducted in drift scan mode with the Bordeaux automated meridian circle in the declination band [+11 ; +18]. The resulting astrometric catalog includes about 2 300 000 stars down to the magnitude limit V_M_=16.3. Nearly all stars (96%) have been observed at least 6 times, the catalog being complete down to V_M_=15.4. The median internal standard error in position is about 35mas in the magnitude range 11<V_M_<15, which degrades to about 50mas when the faintest stars are considered. M2000 provides also one band photometry with a median internal standard error of 0.04mag. Comparisons with the Hipparcos and bright part of Tycho-2 catalogs have enabled to estimate external errors in position to be lower than 40mas. In this zone and at epoch 1998, the faint part of Tycho-2 is found to have an accuracy of 116mas in alpha instead of 82mas deduced from the model-based standard errors given in the catalog.
64. MDFC Version 10
- ID:
- ivo://CDS.VizieR/II/361
- Title:
- MDFC Version 10
- Short Name:
- II/361
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Mid-infrared stellar Diameters and Fluxes compilation Catalogue (MDFC) dedicated to long-baseline interferometry at mid-infrared wavelengths (3-13um). It gathers data for half a million stars, i.e. nearly all the stars of the Hipparcos-Tycho catalogue whose spectral type is reported in the SIMBAD data base. We cross-match 26 data bases to provide basic information, binarity elements, angular diameter, magnitude and flux in the near and mid-infrared, as well as flags that allow us to identify the potential calibrators. The catalogue covers the entire sky with 465857 stars, mainly dwarfs and giants from B to M spectral types closer than 18kpc. The smallest reported values reach 0.16uJy in L and 0.1uJy in N for the flux, and 2-microarcsec for the angular diameter. We build four lists of calibrator candidates for the L and Nbands suitable with the Very Large Telescope Interferometer (VLTI) sub- and main arrays using the MATISSE instrument. We identify 1621 candidates for L and 44 candidates for N with the Auxiliary Telescopes (ATs), 375 candidates for both bands with the ATs, and 259 candidates for both bands with the Unit Telescopes (UTs). Predominantly cool giants, these sources are small and bright enough to belong to the primary lists of calibrator candidates. In the near future, we plan to measure their angular diameter with 1 per cent accuracy.
- ID:
- ivo://CDS.VizieR/J/A+A/602/A100
- Title:
- Merging groups and clusters from the SDSS data
- Short Name:
- J/A+A/602/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxy groups and clusters are the main tools to test cosmological models and to study the environmental effect of galaxy formation. This work aims to provide a catalogue of galaxy groups/clusters and potentially merging systems based on the SDSS main galaxy survey. We identify galaxy groups and clusters using the modified friends-of-friends (FoF) group finder that is designed specifically for flux-limited galaxy surveys. FoF group membership is refined by multimodality analysis to find subgroups and by using the group virial radius and escape velocity to expose unbound galaxies. We look for merging systems by comparing distances between group centres with group radii. The analysis results in a catalogue of 88 662 galaxy groups with at least two members. Among them are 6873 systems with at least 6 members which we consider as more reliable groups. We find 498 group mergers with up to six groups.
- ID:
- ivo://CDS.VizieR/J/PAZh/24/93
- Title:
- M 31 reference catalog
- Short Name:
- J/PAZh/24/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compiled a catalog of 421 references 12-15mag stars for determining accurate positions of objects in the region of M 31. We also compiled a star chart, which is provided as an Internet Web service, for identifying the catalogued reference stars on the plates of observers. AQccurate positions and a finding chart are given for 33 reference 15-17mag stars in a 10'x12' field near the center of M 31.
- ID:
- ivo://CDS.VizieR/J/A+A/630/A101
- Title:
- Multi-frequency celestial reference frame
- Short Name:
- J/A+A/630/A101
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a celestial reference frame (CRF) based on the combination of independent, multifrequency radio source position catalogs using nearly 40 years of very long baseline interferometry observations at the standard geodetic frequencies at SX band and about 15 years of observations at higher frequencies (K and XKa). The final catalog contains 4617 sources. We produce a multifrequency catalog of radio source positions with full variance-covariance information across all radio source positions of all input catalogs. We combined three catalogs, one observed at 8GHz (X band), one at 24GHz (K band) and one at 32GHz (Ka band). Rather than only using the radio source positions, we developed a new, rigorous combination approach by carrying over the full covariance information through the process of adding normal equation systems. Special validation routines were used to characterize the random and systematic errors between the input reference frames and the combined catalog. The resulting CRF contains precise positions of 4617 compact radio astronomical objects, 4536 measured at 8GHz, 824 sources also observed at 24GHz, and 674 at 32GHz. The frame is aligned with ICRF3 within +/-3{mu}as and shows an average positional uncertainty of 0.1mas in right ascension and declination. No significant deformations can be identified. Comparisons with Gaia-CRF remain inconclusive, nonetheless significant differences between all frames can be attested.
- ID:
- ivo://CDS.VizieR/J/A+AS/89/311
- Title:
- Optical positions of 221 radio stars
- Short Name:
- J/A+AS/89/311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains optical positions of 221 radio stars observed with the Bordeaux automatic meridian circle. The observations were strictly differential, a convenient number of FK5 stars being used each night to calculate the instrumental parameters. The mean positions were corrected for chromatic refraction and also for photocenter effect in the case of duplicity. The asymptotic accuracy is expected to be about 0.05" for the Northern stars with a number of observations greater than 25. Some positions have been published previously, and the improved positions given here supersede earlier published data.
- ID:
- ivo://CDS.VizieR/I/97
- Title:
- Perth 75 Catalogue
- Short Name:
- I/97
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains results of approximately 60000 photoelectric meridian circle observations made at the Perth Observatory for 1156 FK4 and 1433 FK4 Supplement stars south of declination +38 degrees. The catalog reports proper motions and positions at epoch and equinox B1950.0. The data used to derive the epoch 1950 positions are included in the catalog so that originally observed positions may be recomputed and used for geodetic purposes until the FK5 becomes available. The mean error of an individual position in this catalog is 0.07" in right ascension and 0.13" in declination at a zenith distance of 45 degrees, while the mean error of the PERTH 75 system is 0.05" in right ascension and 0.10" in declination. The positions do not contain the large systematic errors of the FK4 (Fricke and Kopff 1963), which can be, for example 0.3" in right ascension for declination < -75 degrees. Data in the catalog included FK4 (FK4S) number, observed visual magnitude, spectral type used for computing refraction, right ascension and declination (equinox and epoch B1950.0), annual proper motion, observed residuals, numbers of accepted observations, and code to indicate if parallax and/or radial velocity has been used in computing apparent positions.
- ID:
- ivo://CDS.VizieR/J/A+AS/132/233
- Title:
- PHA I observations
- Short Name:
- J/A+AS/132/233
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Photoelectric Astrolabe Mark I (PHA I) has been revised with a new combined prism which could work as an almucantar with zenith distance of 45 degree, to measure continuous declinations at the latitude of Irkutsk, Russia ({phi}=52 degree). The PHA I has been working at the astronomical base of VS NIIFTRI in Irkutsk since Nov. 1995, based on an international cooperation agreement of near 4 years for star catalogue and EOP measurements. The first observing program was ended in June 1997, giving corrections in both right ascension and declination to 200 stars with no blind zone in declination determination, which most astrolabe catalogues in the world usually would have.
