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- ID:
- ivo://CDS.VizieR/J/A+A/417/499
- Title:
- Spectrophotometry of Virgo cluster galaxies
- Short Name:
- J/A+A/417/499
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Drift-scan mode (3600-6800{AA}) spectra with 500<R<1000 resolution are presented for 333 galaxies members to nearby clusters, covering the whole Hubble sequence. The majority (225) were obtained for galaxies in the Virgo cluster where a completeness of 36%, if all Hubble types are considered, and of 5 %, restricting to late-types, was reached at mp<=16. Our data can be therefore considered representative of the integrated spectral properties of giant and dwarf galaxies in this cluster. Intensities and equivalent widths (EWs) are derived for the principal lines, both in emission and in absorption. Deblending of the underlying absorption from emission was achieved in most cases.
- ID:
- ivo://CDS.VizieR/III/143
- Title:
- Spectrophotometry of Wolf-Rayet Stars
- Short Name:
- III/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalog contains spectrophotometry at approximately 10-Angstrom resolution for 173 southern Wolf-Rayet stars. All observations were made at the Cerro Tololo Inter-American Observatory between November 1981 and February 1985 with SIT-vidicon detector. The catalog includes synthetic photometry, and fluxes in the range 3400-7300 Angstroms for most known Wolf-Rayet stars in the Large Magellanic Cloud and in the range 3400-4700 Angstroms for all known Wolf-Rayet stars in the Small Magellanic Cloud.
- ID:
- ivo://CDS.VizieR/J/A+A/307/215
- Title:
- Spectrophotomety of planetary nebulae
- Short Name:
- J/A+A/307/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectrohotometric observations at high signal-to-noise ratio for a sample of 62 planetary nebulae are presented, together with the plasma and abundance analyses. The objects were selected homogeneously from the `Strasbourg-ESO Catalogue of Galactic Planetary Nebulae' by their height above the disk (over 300pc) and their H{beta} surface brightness (between 10^-12^ and 10^-14^mW/m^2^/arcsec^2^). The abundances of O, S, Ar, and Cl are tighly correlated. The N/O ratio shows a wide range of values, independent of He or O abundance.
- ID:
- ivo://CDS.VizieR/J/A+A/482/989
- Title:
- Spectropolarimetric model for Earth-like planets
- Short Name:
- J/A+A/482/989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of numerical simulations of flux F and degree of polarization P of light that is reflected by Earth-like extrasolar planets orbiting solar type stars. Our results are presented as functions of the wavelength (from 0.3 to 1.0{mu}m, with 0.001{mu}m spectral resolution) and as functions of the planetary phase angle. We use different surface coverages for our model planets, including vegetation and a Fresnel reflecting ocean, and clear and cloudy atmospheres.
- ID:
- ivo://CDS.VizieR/J/ApJ/786/120
- Title:
- Spectropolarimetric survey of classical Be stars
- Short Name:
- J/ApJ/786/120
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent observational and theoretical studies of classical Be stars have established the utility of polarization color diagrams (PCDs) in helping to constrain the time-dependent mass decretion rates of these systems. We expand on our pilot observational study of this phenomenon, and report the detailed analysis of a long-term (1989-2004) spectropolarimetric survey of nine additional classical Be stars, including systems exhibiting evidence of partial disk-loss/disk-growth episodes as well as systems exhibiting long-term stable disks. After carefully characterizing and removing the interstellar polarization along the line of sight to each of these targets, we analyze their intrinsic polarization behavior. We find that many steady-state Be disks pause at the top of the PCD, as predicted by theory. We also observe sharp declines in the Balmer jump polarization for later spectral type, near edge-on steady-state disks, again as recently predicted by theory, likely caused when the base density of the disk is very high, and the outer region of the edge-on disk starts to self absorb a significant number of Balmer jump photons. The intrinsic V-band polarization and polarization position angle of {gamma} Cas exhibits variations that seem to phase with the orbital period of a known one-armed density structure in this disk, similar to the theoretical predictions of Halonen & Jones. We also observe stochastic jumps in the intrinsic polarization across the Balmer jump of several known Be+sdO systems, and speculate that the thermal inflation of part of the outer region of these disks could be responsible for producing this observational phenomenon. Finally, we estimate the base densities of this sample of stars to be between ~8x10^-11^ and ~4x10^-12^ g/cm^3^ during quasi steady state periods given there maximum observed polarization.
- ID:
- ivo://CDS.VizieR/J/ApJ/815/49
- Title:
- Spectropolarimetric survey of radio sources
- Short Name:
- J/ApJ/815/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a broadband spectropolarimetric survey of 563 discrete, mostly unresolved radio sources between 1.3 and 2.0 GHz using data taken with the Australia Telescope Compact Array. We have used rotation-measure synthesis to identify Faraday-complex polarized sources, those objects whose frequency-dependent polarization behavior indicates the presence of material possessing complicated magnetoionic structure along the line of sight (LOS). For sources classified as Faraday-complex, we have analyzed a number of their radio and multiwavelength properties to determine whether they differ from Faraday-simple polarized sources (sources for which LOS magnetoionic structures are comparatively simple) in these properties. We use this information to constrain the physical nature of the magnetoionic structures responsible for generating the observed complexity. We detect Faraday complexity in 12% of polarized sources at ~1' resolution, but we demonstrate that underlying signal-to-noise limitations mean the true percentage is likely to be significantly higher in the polarized radio source population. We find that the properties of Faraday-complex objects are diverse, but that complexity is most often associated with depolarization of extended radio sources possessing a relatively steep total intensity spectrum. We find an association between Faraday complexity and LOS structure in the Galactic interstellar medium (ISM) and claim that a significant proportion of the Faraday complexity we observe may be generated at interfaces of the ISM associated with ionization fronts near neutral hydrogen structures. Galaxy cluster environments and internally generated Faraday complexity provide possible alternative explanations in some cases.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A113
- Title:
- Spectropolarimetric survey of white dwarfs
- Short Name:
- J/A+A/618/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Our knowledge of the magnetism in white dwarfs is based on an observational dataset that is biased in favour of stars with very strong magnetic fields. Most of the field measurements available in the literature have a relatively low sensitivity, while current instruments allow us to detect magnetic fields of white dwarfs with sub-kG precision. With the aim of obtaining a more complete view of the incidence of magnetic fields in degenerate stars, we have started a long-term campaign of high-precision spectropolarimetric observations of white dwarfs. Here we report the results obtained so far with the low-resolution FORS2 instrument of the ESO VLT and the medium-resolution ISIS instrument of the WHT. We have considered a sample of 48 stars, of which five are known magnetic or suspected magnetic stars, and obtained new longitudinal magnetic field measurements with a mean uncertainty of about 0.6kG. Overall, in the course of our survey (the results of which have been partially published in papers devoted to individual stars) we have discovered one new weak-field magnetic white dwarf, confirmed the magnetic nature of another, found that a suspected magnetic star is not magnetic, and suggested two new candidate magnetic white dwarfs. Even combined with data previously obtained in the literature, our sample is not sufficient yet to reach any final conclusions about the actual incidence of very weak magnetic fields in white dwarfs, but we have set the basis to achieve a homogeneous survey of an unbiased sample of white dwarfs. As a by-product, our survey has also enabled us to carry out a detailed characterisation of the ISIS and the FORS2 instruments for the detection of extremely weak magnetic fields in white dwarfs, and in particular to relate the signal-to-noise ratio to measurement uncertainty for white dwarfs of different spectral types. This study will help the optimisation of future observations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2879
- Title:
- Spectropolarimetry of active galaxy 3C 390.3
- Short Name:
- J/MNRAS/448/2879
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Here we present the spectropolarimetric observations of the radio-loud active galaxy 3C 390.3 in the period 2009-2014 (24 epochs). The galaxy has been observed with the 6-m telescope of Special Astrophysical Observatory of the Russian Academy of Science (SAO RAS) using the Spectral Camera with Optical Reducer for Photometric and Interferometric Observations (SCORPIO) spectropolarimeter. We explore the variability and lags in the polarized light of the continuum and broad H{alpha} line. We give the Stokes parameters Q, U, degree of linear polarization P and the position angle of the polarization plane, {phi}, for 24 epochs. We find a small lag (10-40 d) between the unpolarized and polarized continuum that is significantly smaller than the estimated lags for the unpolarized broad emission lines (lag(H{alpha}) ~138-186 and lag(H{beta}) ~60-79 d). This shows that the region of the variable polarized continuum is significantly smaller than the broad line region, indicating that a part of the polarized continuum is coming from the jet. The lag of the polarized light in the H{alpha} line (89-156 d) indicates an additional component to the disc one that has an outflowing velocity of ~-1200 km/s. This region seems to depolarize the polarized broad H{alpha} line emitted from the disc and scattered in the inner part of the torus.
- ID:
- ivo://CDS.VizieR/J/ApJ/709/1306
- Title:
- Spectropolarimetry of 60 Cyg and {pi} Aqr
- Short Name:
- J/ApJ/709/1306
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Classical Be stars are known to occasionally transition from having a gaseous circumstellar disk ("Be phase") to a state in which all observational evidence for the presence of these disks disappears ("normal B-star phase"). We present one of the most comprehensive spectropolarimetric views to date of such a transition for two Be stars, {pi} Aquarii and 60 Cygni. The disk-loss episode of 60 Cyg was characterized by a generally monotonic decrease in emission strength over a timescale of ~1000 days from the maximum V-band polarization to the minimum H{alpha} equivalent width, consistent with the viscous timescale of the disk, assuming {alpha}~0.14. {pi} Aqr's disk loss was episodic in nature and occurred over a timescale of ~2440 days.