- ID:
- ivo://CDS.VizieR/J/PASP/106/949
- Title:
- Multicolor polarimetry of Be stars
- Short Name:
- J/PASP/106/949
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical polarization data in the UBVRI filter system for eight bright northern Be stars are presented here as the continuation of a long-term monitoring project begun in 1984. There are no strong cases of night-to-night variability, and the only star showing unmistakable changes in polarization from year to year over the nine years covered by the program is Pi Aquarii. Even though the observed sample spans a wide range in spectral type, vsini, and degree of intrinsic polarization, the normalized wavelength dependence of the polarization is surprisingly similar for all of the stars. Analysis of the wavelength dependence of the variable polarization of {pi} Aqr in terms of a simple equatorial-disk model suggests that changes in the circumstellar electron number density alone may be sufficient to account for the observations, but it is not clear what real physical mechanism is involved.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/240/785
- Title:
- Multicolour photometry of Sersic 129-01
- Short Name:
- J/MNRAS/240/785
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/AJ/154/231
- Title:
- Multi-epoch multi-band photometry of B1-392
- Short Name:
- J/AJ/154/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Ongoing and future surveys with repeat imaging in multiple bands are producing (or will produce) time-spaced measurements of brightness, resulting in the identification of large numbers of variable sources in the sky. A large fraction of these are periodic variables: compilations of these are of scientific interest for a variety of purposes. Unavoidably, the data sets from many such surveys not only have sparse sampling, but also have embedded frequencies in the observing cadence that beat against the natural periodicities of any object under investigation. Such limitations can make period determination ambiguous and uncertain. For multiband data sets with asynchronous measurements in multiple passbands, we wish to maximally use the information on periodicity in a manner that is agnostic of differences in the light-curve shapes across the different channels. Given large volumes of data, computational efficiency is also at a premium. This paper develops and presents a computationally economic method for determining periodicity that combines the results from two different classes of period-determination algorithms. The underlying principles are illustrated through examples. The effectiveness of this approach for combining asynchronously sampled measurements in multiple observables that share an underlying fundamental frequency is also demonstrated.
- ID:
- ivo://CDS.VizieR/J/A+A/520/A89
- Title:
- Multi-epoch photometry of {delta} Ori
- Short Name:
- J/A+A/520/A89
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For years, {delta} Ori was considered a normal binary with an O9.5 II primary exhibiting apsidal-line advance. However, in 2002 radial-velocity curves of both binary components derived from the IUE and optical spectra using the cross-correlation technique have been published by Harvin et al. (2002ApJ...565.1216H); surprisingly low masses of 11.2 and 5.6M_{sun}_ were obtained. We obtained new spectra in the red spectral region and new UBV photometry. Using all published photometry and radial velocities, we deduced more accurate orbital and apsidal line periods. The main result of this paper is to show that the observed line spectra of {delta} Ori are composed of the lines of the O9.5 II primary and a similarly hot tertiary, while the lines of a cooler B-type secondary are too faint to be detected in the available spectra. The character of the light curve (low-amplitude partial eclipses and a non-negligible scatter of the data) does not allow for a unique light-curve solution. Nevertheless, we show that the assumption of normal primary-component mass and radius corresponding to the O9.5 II classification (25M_{sun}_, 16-17R_{sun}_) leads to consistent parameters for the system.
- ID:
- ivo://CDS.VizieR/J/other/RMxAA/35.187
- Title:
- Multifrequency catalog of LINERs
- Short Name:
- J/other/RMxAA/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first Catalog of Low Ionization Emission Line Galaxies (LINERs or Liners, which is the simplest name, and which we shall adopt in what follows). The Catalog "MCL" (Multifrequency Catalog of Liners), contains 476 entries and contains both broad-band and monochromatic emission data (ranging from radio to X-ray frequencies) of colors, and other data compiled from the literature and various data bases, as indicated in the references. Most of the galaxies can be considered "pure" Liners on the basis of the Veilleux & Osterbrock (1987ApJS...63..295V) classification as suggested by Ho, Filippenko, & Sargent (1997ApJS..112..315H). However, a considerable number of transition (Liners-H II or Liners-Starburst) objects are also included. One of the open questions, is whether Liners should be considered as a class of galaxies (like Seyfert galaxies for instance) or rather, as an heterogeneous group of objects. We believe the study of Liners as a group is very interesting, precisely because they very likely represent a transition between non-thermal and starburst activity, and probably also between "active" and "non- active" galaxies. This catalog may be used as a basis for statistical research. A preliminary discussion of the main statistical properties of Liners, in the range from radio to X-ray frequencies, is given here.
- ID:
- ivo://CDS.VizieR/J/A+AS/114/341
- Title:
- Multifrequency monitoring of RU Lupi
- Short Name:
- J/A+AS/114/341
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the results of a long campaign of coordinated (sometimes simultaneous) multifrequency observations, from X-ray to radio wavelengths of the extreme T Tauri star RU Lupi. The large amount of data obtained can be useful to understanding the physics governing the intriguing behaviour of this pre-main-sequence star. In particular, from the whole set of data, a model with a protoplanetary accretion disk around a moderately magnetic star seems to be the most promising picture for this source.
- ID:
- ivo://CDS.VizieR/J/ApJ/442/523
- Title:
- Multiparam. Analysis, Einstein Sample. II.
- Short Name:
- J/ApJ/442/523
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have conducted bivariate and multivariate statistical analysis of data measuring the integrated luminosity, shape, and potential depth of the Einstein sample of early-type galaxies (presented by Fabbiano et al. =1992ApJS...80..531F). We find significant correlations between the X-ray properties and the axial ratios (a/b) of our sample, such that the roundest systems tend to have the highest L_X and L_X/L_B. The most radio-loud objects are also the roundest. We confirm the assertion of Bender et al. (1989A&A...217...35B) that galaxies with high L_X are boxy (have negative a_4). Both a/b and a_4 are correlated with L_B, but not with IRAS 12 um and 100 um luminosities. There are strong correlations between L_X, Mg_2 and sigma_v in the sense that those systems with the deepest potential wells have the highest L_X and Mg_2. Thus the depth of the potential well appears to govern both the ability to retain an ISM at the present epoch and to retain the enriched ejecta of early star formation bursts. Both L_X/L_B and L_6 (the 6 cm radio luminosity) show threshold effects with sigma_v, exhibiting sharp increases at log(sigma_v) ~ 2.2. Finally, there is clearly an interrelationship between the various stellar and structural parameters: The scatter in the bivariate relationships between the shape parameters (a/b and a_4) and the depth parameter (sigma_v) is a function of abundance in the sense that, for a given a_4 or a/b, the systems with the highest sigma_v also have the highest Mg_2. Furthermore, for a constant sigma_v, disky galaxies tend to have higher Mg_2 than boxy ones. Alternatively, for a given abundance, boxy ellipticals tend to be more massive than disky ellipticals. One possibility is that early-type galaxies of a given mass, originating from mergers (boxy ellipticals), have lower abundances than "primordial" (disky) early-type galaxies. Another is that disky inner isophotes are due not to primordial dissipational collapse, but to either the self-gravitating inner disks of captured spirals or the dissipational collapse of new disk structures from the premerger ISM. The high measured nuclear Mg_2 values would thus be due to enrichment from secondary bursts of star formation triggered by the merging event.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A65
- Title:
- Multiphotometry of M31 outer halo globular clusters
- Short Name:
- J/A+A/623/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we present photometry of 53 globular clusters (GCs) in the M31 outer halo, including the GALEX FUV and NUV, SDSS ugriz, 15 intermediate-band filters of BATC, and 2MASS JHKs bands. By comparing the multicolour photometry with stellar population synthesis models, we determine the metallicities, ages, and masses for these GCs, aiming to probe the merging/accretion history of M31. We find no clear trend of metallicity and mass with the de-projected radius. The halo GCs with age younger than ~8Gyr are mostly located at the de-projected radii around 100kpc, but this may be due to a selection effect. We also find that the halo GCs have consistent metallicities with their spatially-associated substructures, which provides further evidence of the physical association between them. Both the disk and halo GCs in M31 show a bimodal luminosity distribution. However, we should emphasize that there are more faint halo GCs which are not being seen in the disk. There are more faint halo GCs than the disk ones, and these faint GCs constitute the fainter part in the luminosity function. The bimodal luminosity function of the halo GCs may reflect different origin or evolution environment in their original hosts. The M31 halo GCs includes one intermediate metallicity group (-1.5<[Fe/H]<-0.4) and one metal-poor group ([Fe/H]<-1.5), while the disk GCs have one metal-rich group more. There are considerable differences between the halo GCs in M31 and the Milky Way (MW). The total number of M31 GCs is approximately three times more numerous than that of the MW, however, M31 has about six times the number of halo GCs in the MW. Compared to M31 halo GCs, the Galactic halo ones are mostly metal-poor. Both the numerous halo GCs and the higher-metallicity component are suggestive of an active merger history of M31.
- ID:
- ivo://CDS.VizieR/J/A+AS/121/223
- Title:
- Multiphotometry of NGC 6611
- Short Name:
- J/A+AS/121/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- For the search of Herbig Ae/Be objects in the extremely young open cluster NGC 6611 we have selected a sample of 52 pre-main sequence candidates, discovered by Walker (1961ApJ...133..438W), Sagar & Joshi (1979Ap&SS..66....3S), Chini & Wargau (1990A&A...227..213C) and The et al. (1990A&AS...82..319T). We continue the approach of the last paper by studying each star individually with new and unpublished Walraven WULBV, Johnson/Cousins UBV(RI)_C_ and Johnson JHKLM photometric data as well as low resolution spectroscopy. For a description of the Walraven, UBVRI, IJHKLMN and RI Cousins photometric systems, see e.g. <GCPD/11>, <GCPD/08>, <GCPD/09> and <GCPD/54>
- ID:
- ivo://CDS.VizieR/J/AJ/159/139
- Title:
- Multiple M dwarf stars with Robo-AO and Gaia DR2
- Short Name:
- J/AJ/159/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze observations from Autonomous laser-adaptive-optics for few-meter-class telescopes (Robo-AO)'s field M dwarf survey taken on the 2.1m Kitt Peak telescope and perform a multiplicity comparison with Gaia DR2. Through its laser-guided, automated system, the Robo-AO instrument has yielded the largest adaptive optics M dwarf multiplicity survey to date. After developing an interface to visually identify and locate stellar companions, we selected 11 low-significance Robo-AO detections for follow-up on the Keck II telescope using NIRC2. In the Robo-AO survey we find 553 candidate companions within 4" around 534 stars out of 5566 unique targets, most of which are new discoveries. Using a position cross-match with DR2 on all targets, we assess the binary recoverability of Gaia DR2 and compare the properties of multiples resolved by both Robo-AO and Gaia. The catalog of nearby M dwarf systems and their basic properties presented here can assist other surveys which observe these stars, such as the NASA Transiting Exoplanet Survey Satellite (TESS) mission.
