- ID:
- ivo://CDS.VizieR/J/A+A/624/A42
- Title:
- H2O megamaser galaxies radio continuum 5GHz data
- Short Name:
- J/A+A/624/A42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An essential part of the paradigm describing active galactic nuclei is the alignment between the radio jet and the associated rotation axis of the sub-pc accretion disks. Because of the small linear and angular scales involved, this alignment has not yet been checked in a sufficient number of low luminosity active galactic nuclei (LLAGNs). The project examines the validity of this paradigm by measuring the radio continuum on the same physical scale as the accretion disks to investigate any possible connection between these disks and the radio continuum. We observed a sample of 18 LLAGNs in the 4.8GHz (6cm) radio continuum using the Very Long Baseline Array (VLBA) with 3.3-6.5ms resolution. The sources were selected to show both an edge-on accretion disk revealed by 22GHz H_2_O megamaser emission and signatures of a radio jet. Furthermore, the sources were previously detected in 33GHz radio continuum observations made with the Very Large Array. Five out of 18 galaxies observed were detected at 8{sigma} or higher levels (Mrk 0001, Mrk 1210, Mrk 1419, NGC 2273, and UGC 3193). While these five sources are known to have maser disks, four of them exhibit a maser disk with known orientation. For all four of these sources, the radio continuum is misaligned relative to the rotation axis of the maser disk, but with a 99.1% confidence level, the orientations are not random and are confined to a cone within 32{deg} of the maser disk's normal. Among the four sources the misalignment of the radio continuum with respect to the normal vector to the maser disk is smaller when the inner radius of the maser disk is larger. Furthermore, a correlation is observed between the 5GHz VLBA radio continuum and the [OIII] luminosity and also with the H_2_O maser disk's inner radius.
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Search Results
- ID:
- ivo://CDS.VizieR/J/BaltA/20/89
- Title:
- Homegenized effective temperatures of 800 stars
- Short Name:
- J/BaltA/20/89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Some selected catalogs of the effective temperatures (Teff) for F, G and K stars are analyzed. By an improved technique we estimate the external errors of these catalogs from data intercomparisons. The Teff values are then averaged with the appropriate weights to produce a mean homogeneous catalog based on the selected data. This catalog, containing 800 stars, is compared with some other independent catalogs for estimating their external errors. The data may be used as a source of reliable homogeneous values of Teff, together with their errors.
- ID:
- ivo://CDS.VizieR/J/other/AstBu/72.257
- Title:
- Homogeneous Catalog of Open Cluster Param.
- Short Name:
- J/other/AstBu/72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the current version of the "Homogeneous Catalog of Open Clusters Parameters", supported by our group during last decades. The catalog is created on the base of redetermination of the main parameters of clusters (colour excesses, distances from the Sun and ages) using published photometric measurements, in particular, according to the 2MASS catalog of point sources. At present, the catalog contains parameters of 1035 clusters. The catalog includes the radial velocities data for 496 open clusters. All clusters of the catalog have estimates of the components of proper motion.
- ID:
- ivo://CDS.VizieR/II/168
- Title:
- Homogeneous Means in the UBV System
- Short Name:
- II/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The present catalog supersedes an earlier edition of Nicolet (1978). It is a collection of weighted mean photoelectric values (V, B-V, U-B) for stars measured in the UBV system. The mean values were computed by combining all individual measurements compiled in the catalog of Mermilliod (1987), except those that were clearly found to be erroneous for some reason or another. Some newer observations compiled since 1987 are also included in the means. The procedure for computing the homogeneous means involved the calculation of normal averages weighted by the number of observations in each list (unity when not published). New weights are assigned based on the deviation of each value from the previous mean, then a new weighted mean is computed. This technique is not as rigorous as that used by Nicolet (comparison of each list with the standard system master list), but the latter cannot often be realized effectively in practice, since many lists do not contain enough stars in common with a standard list. Also, there are now so many references (more than 1500) that it is not feasible to analyze each publication with respect to a standard list. This edition of the catalog contains 92964 stars measured since the introduction of the UBV system in 1953. The data included are star identification in the Geneva coded numbering system, double and variable codes, UBV data and their standard deviations, and number of observations. A second file contains the definition of the coded numbering system. The catalog was prepared at the Institut d'Astronomie de l'Universite de Lausanne in Geneva.
- ID:
- ivo://CDS.VizieR/II/80
- Title:
- Homogeneous Photometry Bright Stars on DDO System
- Short Name:
- II/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of homogeneous photometry of bright stars on the DDO (System McClure and Forrester 1981) is a compilation of DDO photometry of 2196 bright G and K stars prepared from observations made at Kitt Peak National and Cerro Tololo Inter-American Observatories over the last several years using filter sets well matched to the standard system. The catalogue includes a large number of DDO stars whose data have been taken directly from the standard-star paper of McClure (1976AJ.....81..182M), plus a representative sample of stars selected from the Catalogue of Bright Stars (Hoffleit 1964, see Cat. V/50) and the Catalogue of High-Velocity Stars (Eggen 1964, see Cat. V/11) to have good velocities, spectral types and freedom from companion contamination. The catalogue contains HD Catalogue numbers, DM identifications; and the standard photometric indices of the DDO system. The number of observations from which each index was determined is also given, along with standard errors. The DDO 6-filter has the following peak wavelengths and widths: ------------------------ Filter Peak Width [nm] [nm] ------------------------ 35 346.0 38.3 38 381.5 33.0 41 416.6 8.3 42 425.7 7.3 45 451.7 7.6 48 488.6 18.6 ------------------------
- ID:
- ivo://CDS.VizieR/J/A+A/547/A13
- Title:
- Homogeneous sample of F6-K4 Hyades stars
- Short Name:
- J/A+A/547/A13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar kinematic groups are kinematical coherent groups of stars that might have a common origin. These groups are dispersed throughout the Galaxy over time by the tidal effects of both Galactic rotation and disc heating, although their chemical content remains unchanged. The aim of chemical tagging is to establish that the abundances of every element in the analysis are homogeneous among the members. We study the case of the Hyades Supercluster to compile a reliable list of members (FGK stars) based on our chemical tagging analysis. For a total of 61 stars from the Hyades Supercluster, stellar atmospheric parameters (Teff, logg, {ksi}, and [Fe/H]) are determined using our code called StePar, which is based on the sensitivity to the stellar atmospherics parameters of the iron EWs measured in the spectra. We derive the chemical abundances of 20 elements and find that their [X/Fe] ratios are consistent with Galactic abundance trends reported in previous studies. The chemical tagging method is applied with a carefully developed differential abundance analysis of each candidate member of the Hyades Supercluster, using a well-known member of the Hyades cluster as a reference (vB 153). We find that only 28 stars (26 dwarfs and 2 giants) are members, i.e. that 46% of our candidates are members based on the differential abundance analysis. This result confirms that the Hyades Supercluster cannot originate solely from the Hyades cluster.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A127
- Title:
- Homogeneous sample of 34000 M7-M9.5 dwarfs
- Short Name:
- J/A+A/623/A127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The space density of late M dwarfs, sub-types M7 to M9.5, is not well determined. We have applied the photo-type method of Skrzypek et al. to iz photometry from SDSS and YJHK photometry from UKIDSS, over an effective area of 3070deg^2^, to produce a new, bright J(Vega)<17.5, homogeneous sample of 33665 M7 to M9.5 dwarfs. The typical S/N of each source summed over the 6 bands is >100. Classifications are provided to the nearest half spectral sub-type. Through comparison with the classifications in the BUD spectroscopic sample of Schmidt et al. (2010, Cat. J/AJ/139/1808), the typing is shown to be accurately calibrated to the BUD classifications, with a precision better than 0.5 sub-types rms, i.e. is as precise as good spectroscopic classification. Sources with large chisq>20 include several catalogued late-type subdwarfs. The new sample of late M dwarfs is highly complete, but there is a bias in the classification of rare peculiar blue or red objects. For example L subdwarfs are misclassified towards earlier types by approximately two spectral sub-types. We estimate that this bias affects only ~1% of sources. Therefore the sample is well suited for measuring the luminosity function, as well as investigating the softening towards the Galactic plane of the exponential variation of density with height.
- ID:
- ivo://CDS.VizieR/J/A+A/650/A182
- Title:
- Homogeneous study of Herbig Ae/Be stars
- Short Name:
- J/A+A/650/A182
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Herbig Ae/Be stars (HAeBes) have so far been studied based on relatively small samples that are scattered throughout the sky. Their fundamental stellar and circumstellar parameters and statistical properties were derived with heterogeneous approaches before Gaia. Our main goal is to contribute to the study of HAeBes from the largest sample of such sources to date, for which stellar and circumstellar properties have been determined homogeneously from the analysis of the spectral energy distributions (SEDs) and Gaia EDR3 parallaxes and photometry. Multiwavelength photometry was compiled for 209 bona fide HAeBes for which Gaia EDR3 distances were estimated. Using the Virtual Observatory SED Analyser (VOSA), photospheric models were fit to the optical SEDs to derive stellar parameters, and the excesses at infrared (IR) and longer wavelengths were characterized to derive several circumstellar properties. A statistical analysis was carried out to show the potential use of such a large dataset. The stellar temperature, luminosity, radius, mass, and age were derived for each star based on optical photometry. In addition, their IR SEDs were classified according to two different schemes, and their mass accretion rates, disk masses, and the sizes of the inner dust holes were also estimated uniformly. The initial mass function fits the stellar mass distribution of the sample within 2<M_star_/M_{sun}_<12. In this aspect, the sample is therefore representative of the HAeBe regime and can be used for statistical purposes when it is taken into account that the boundaries are not well probed. Our statistical study does not reveal any connection between the SED shape from the Meeus et al., 2001A&A...365..476M classification and the presence of transitional disks, which are identified here based on the SEDs that show an IR excess starting at the K band or longer wavelengths. In contrast, only ~28% of the HAeBes have transitional disks, and the related dust disk holes are more frequent in HBes than in HAes (~34% vs 15%). The relatively small inner disk holes and old stellar ages estimated for most transitional HAes indicate that photoevaporation cannot be the main mechanism driving disk dissipation in these sources. In contrast, the inner disk holes and ages of most transitional HBes are consistent with the photoevaporation scenario, although these results alone do not unambiguously discard other disk dissipation mechanisms. The complete dataset is available online through a Virtual Observatory- compliant archive, representing the most recent reference for statistical studies on the HAeBe regime. VOSA is a complementary tool for the future characterization of newly identified HAeBes.
- ID:
- ivo://archive.stsci.edu/hut
- Title:
- Hopkins Ultraviolet Telescope
- Short Name:
- HUT
- Date:
- 22 Jul 2020 21:30:05
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The Hopkins Ultraviolet Telescope (HUT) was a shuttle-borne instrument used to obtain ultraviolet spectra in the far ultraviolet region of the spectrum. It was part of the ASTRO payload complement of three co-mounted instruments that flew in December 1990 and March 1995 as Space Shuttle missions. More than 650 spectra were obtained of 340 targets. In April, 2013, the HUT data was reprocessed to improve calibration, expand metadata, add new data products, and update file formats. The current cone service uses the metadata from these reprocessed files.
- ID:
- ivo://CDS.VizieR/J/MNRAS/470/1462
- Title:
- HOPS. III. Dense molecular gas properties
- Short Name:
- J/MNRAS/470/1462
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The H_2_O Southern Galactic Plane Survey (HOPS) has mapped 100deg^2^ of the Galactic plane for water masers and thermal molecular line emission using the 22m Mopra telescope. We describe the automated spectral-line fitting pipelines used to determine the properties of emission detected in HOPS data cubes, and use these to derive the physical and kinematic properties of gas in the survey. A combination of the angular resolution, sensitivity, velocity resolution and high critical density of lines targeted make the HOPS data cubes ideally suited to finding precursor clouds to the most massive and dense stellar clusters in the Galaxy. We compile a list of the most massive HOPS ammonia regions and investigate whether any may be young massive cluster progenitor gas clouds. HOPS is also ideally suited to trace the flows of dense gas in the Galactic Centre. We find the kinematic structure of gas within the inner 500pc of the Galaxy is consistent with recent predictions for the dynamical evolution of gas flows in the centre of the Milky Way. We confirm a recent finding that the dense gas in the inner 100pc has an oscillatory kinematic structure with characteristic length-scale of 20pc, and also identify similar oscillatory kinematic structure in the gas at radii larger than 100pc. Finally, we make all of the above fits and the remaining HOPS data cubes across the 100deg^2^ of the survey available to the community.