- ID:
- ivo://CDS.VizieR/J/ApJ/844/L4
- Title:
- PS1 RRab stars for tracing outer Virgo overdensity
- Short Name:
- J/ApJ/844/L4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of spatially distinct stellar density features near the apocenters of the Sagittarius (Sgr) stream's main leading and trailing arm. These features are clearly visible in a high-fidelity stellar halo map that is based on RR Lyrae from Pan-STARRS1: there is a plume of stars 10kpc beyond the apocenter of the leading arm, and there is a "spur" extending to 130kpc, almost 30kpc beyond the previously detected apocenter of the trailing arm. Such an apocenter substructure is qualitatively expected in any Sgr stream model, as stars stripped from the progenitor at different pericenter passages become spatially separated there. The morphology of these new Sgr stream substructures could provide much-needed new clues and constraints for modeling the Sgr system, including the level of dynamical friction that Sgr has experienced. We also report the discovery of a new, presumably unrelated halo substructure at 80kpc from the Sun and 10{deg} from the Sgr orbital plane, which we dub the outer Virgo overdensity.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/572/A34
- Title:
- Pulsating solar-like stars in Kepler
- Short Name:
- J/A+A/572/A34
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler ultra-high precision photometry of long and continuous observations provides a unique dataset in which surface rotation and variability can be studied for thousands of stars. Because many of these old field stars also have independently measured asteroseismic ages, measurements of rotation and activity are particularly interesting in the context of age-rotation-activity relations. In particular, age-rotation relations generally lack good calibrators at old ages, a problem that this Kepler sample of old-field stars is uniquely suited to address. We study the surface rotation and photometric magnetic activity of a subset of 540 solar-like stars on the main-sequence and the subgiant branch for which stellar pulsations have been measured.
- ID:
- ivo://CDS.VizieR/J/AJ/162/149
- Title:
- Pulsational changes in classical cepheid X Cygni
- Short Name:
- J/AJ/162/149
- Date:
- 21 Mar 2022 00:19:54
- Publisher:
- CDS
- Description:
- Using an extensive archive for visual observations from the AAVSO, along with published times of maximum light, we determined a new model for the period of X Cygni. The best model is two linear fits for data before and after 1917 (JD2421512). Before that time the period is 16.38438{+/-}0.00036days. After we find a period of 16.386470{+/-}0.000028days. An examination of the O-C values for data after 1917 shows no clear evidence of a constant period change or of sinusoidal variations. The period looks to be constant. From an examination of H-alpha index measurements we find a drop in the value between data before 2013 October and data after 2014 July. This drop is not related to temperature and is likely related to mass loss in the star. Finally, we find that radial-velocity measurements match well with previously published values and show no seasonal variation over the 11yr of data. This again seems to limit the possibility of a companion.
- ID:
- ivo://CDS.VizieR/J/A+A/584/A80
- Title:
- Pulsation model data for delta Cep and eta Aql
- Short Name:
- J/A+A/584/A80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The parallax of pulsation, and its implementations such as the Baade-Wesselink method and the infrared surface brightness technique, is an elegant method to determine distances of pulsating stars in a quasi-geometrical way. However, these classical implementations in general only use a subset of the available observational data. Freedman & Madore (2010ApJ...719..335F) suggested a more physical approach in the implementation of the parallax of pulsation in order to treat all available data. We present a global and model-based parallax-of-pulsation method that enables including any type of observational data in a consistent model fit, the SpectroPhoto-Interferometric modeling of Pulsating Stars (SPIPS). We implemented a simple model consisting of a pulsating sphere with a varying effective temperature and a combination of atmospheric model grids to globally fit radial velocities, spectroscopic data, and interferometric angular diameters. We also parametrized (and adjusted) the reddening and the contribution of the circumstellar envelopes in the near-infrared photometric and interferometric measurements.
- ID:
- ivo://CDS.VizieR/J/PAZh/28/653
- Title:
- Pulsation Modes of Cepheid
- Short Name:
- J/PAZh/28/653
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog of pulsation mode and radii for 64 classical Cepheids based on the 1995-2001 radial velocities observations with the correlation spectrometer.
- ID:
- ivo://CDS.VizieR/J/A+AS/140/55
- Title:
- Pulsation of galactic long-period variables
- Short Name:
- J/A+AS/140/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The absolute K magnitudes and kinematic parameters of about 350 oxygen-rich Long-Period Variable stars are calibrated, by means of an up-to-date maximum-likelihood method, using Hipparcos parallaxes and proper motions together with radial velocities and, as additional data, periods and V-K colour indices. Four groups, differing by their kinematics and mean magnitudes, are found. For each of them, we also obtain the distributions of magnitude, period and de-reddened colour of the base population, as well as de-biased period-luminosity-colour relations and their two-dimensional projections. The SRa semiregulars do not seem to constitute a separate class of LPVs. The SRb appear to belong to two populations of different ages. In a PL diagram, they constitute two evolutionary sequences towards the Mira stage. The Miras of the disk appear to pulsate on a lower-order mode. The slopes of their de-biased PL and PC relations are found to be very different from the ones of the Oxygen Miras of the LMC. This suggests that a significant number of so-called Miras of the LMC are misclassified. This also suggests that the Miras of the LMC do not constitute a homogeneous group, but include a significant proportion of metal-deficient stars, suggesting a relatively smooth star formation history. As a consequence, one may not trivially transpose the LMC period-luminosity relation from one galaxy to the other.
- ID:
- ivo://CDS.VizieR/J/AcA/52/241
- Title:
- QSO candidates in OGLE-II data
- Short Name:
- J/AcA/52/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for faint slowly variable objects was undertaken in the hope of finding QSO candidates behind the Small and Large Magellanic Clouds (SMC and LMC). This search used the optical variability properties of point sources from the Magellanic Cloud OGLE-II photometric data. Objects bluer than V-I=0.9mag and within 17mag<I<20.5mag were studied. Robust variograms/structure functions have been computed for each time-series and only candidates showing a significantly increasing variability over longer time scales were selected. Several light curves were identified as having probable artifacts and were therefore removed. Stars showing signs of periodicity or small trends in their light curves were also removed and we are left with mostly either Be stars ({gamma} Cas stars) or QSO candidates. We present a list of 25 slowly varying objects for SMC and 155 for LMC, out of 15000 and 53000 variable objects respectively. Of these, about 15 objects for the SMC and 118 objects for the LMC are QSO candidates.
- ID:
- ivo://CDS.VizieR/J/ApJ/817/73
- Title:
- QSOs and RR Lyrae in Pan-STARRS1 3{pi} Data
- Short Name:
- J/ApJ/817/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In area and depth, the Pan-STARRS1 (PS1) 3{pi} survey is unique among many-epoch, multi-band surveys and has enormous potential for the all-sky identification of variable sources. PS1 has observed the sky typically seven times in each of its five bands (grizy) over 3.5 years, but unlike SDSS, not simultaneously across the bands. We developed a new approach for quantifying statistical properties of non-simultaneous, sparse, multi-color light curves through light curve structure functions, effectively turning PS1 into a {sim}35-epoch survey. We use this approach to estimate variability amplitudes and timescales for point sources brighter than r_P1_=21.5 mag in the survey. On this basis we provide a catalog of all likely variable point sources and likely QSOs in PS1.
- ID:
- ivo://CDS.VizieR/II/266
- Title:
- QUEST1 200k light curve catalog
- Short Name:
- II/266
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The QUEST (QUasar Equatorial Survey Team) Phase 1 camera has collected multibandpass photometry on a large strip of high Galactic latitude sky over a period of 26 months. This robust data set has been reduced and nightly catalogs compared to determine the photometric variability of the ensemble objects. Subsequent spectroscopic observations have confirmed a subset of the photometric variables as quasars, as previously reported. This paper reports on the details of the data reduction and analysis pipeline and presents multiple bandpass light curves for 198213 QUEST1 objects, along with global variability information and matched Sloan photometry.
- ID:
- ivo://CDS.VizieR/J/AJ/127/1158
- Title:
- QUEST RR Lyrae Survey first catalog
- Short Name:
- J/AJ/127/1158
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the 1m Schmidt telescope of the Llano del Hato Observatory and the QUEST CCD camera, 380{deg}^2^ of the sky have been surveyed for RR Lyrae variables in a band 23 wide in declination (centered at DE=-1{deg}) and covering right ascensions from 4.1h to 6.1h and from 8.0h to 17.0h. The bright limit (due to CCD saturation) and the faint limit are V~13.5 and ~19.7, respectively, which correspond to ~4kpc and ~60kpc from the Sun. We present a catalog of the positions, amplitudes, mean magnitudes, periods, and light curves of the 498 RR Lyrae variables that have been identified in this region of the sky. The majority of these stars (86%) are new discoveries. The completeness of the survey has been estimated from simulations that model the periods and light curves of real RR Lyrae variables and take into account the pattern of epochs of observation. While the completeness of the survey varies with apparent magnitude and with position, almost everywhere in the surveyed region it is quite high (>80%) for the type ab RR Lyrae variables and between 30% and 90% for the low-amplitude type c variables.
