- ID:
- ivo://CDS.VizieR/J/AJ/140/2025
- Title:
- KH 15D (V582 Mon) VI light curves
- Short Name:
- J/AJ/140/2025
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photometry of the unique pre-main-sequence binary system KH 15D is presented, spanning the years 2005-2010. This system has exhibited photometric variations and eclipses over the last ~50 years that are attributed to the effect of a precessing circumbinary disk. Advancement of the occulting edge across the projection on the sky of the binary orbit has continued and the photospheres of both stars are now completely obscured at all times. The system has thus transitioned to a state in which it should be visible only by scattered light, and yet it continues to show a periodic variation on the orbital cycle with an amplitude exceeding 2mag.
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- ID:
- ivo://CDS.VizieR/J/ApJ/853/77
- Title:
- KIC 8462852 ASAS V-band long-term variability
- Short Name:
- J/ApJ/853/77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present ~800 days of photometric monitoring of Boyajian's Star (KIC8462852) from the All-Sky Automated Survey for Supernovae (ASAS-SN) and ~4000d of monitoring from the All Sky Automated Survey (ASAS). We show that from 2015 to the present the brightness of Boyajian's Star has steadily decreased at a rate of 6.3+/-1.4mmag/yr, such that the star is now 1.5% fainter than it was in 2015 February. Moreover, the longer time baseline afforded by ASAS suggests that Boyajian's Star has also undergone two brightening episodes in the past 11 years, rather than only exhibiting a monotonic decline. We analyze a sample of ~1000 comparison stars of similar brightness located in the same ASAS-SN field and demonstrate that the recent fading is significant at >=99.4% confidence. The 2015-2017 dimming rate is consistent with that measured with Kepler data for the time period from 2009 to 2013. This long-term variability is difficult to explain with any of the physical models for the star's behavior proposed to date.
- ID:
- ivo://CDS.VizieR/J/ApJ/847/131
- Title:
- KIC 8462852 one-yr obs. from UV to MIR
- Short Name:
- J/ApJ/847/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To test alternative hypotheses for the behavior of KIC 8462852, we obtained measurements of the star over a wide wavelength range from the UV to the mid- infrared from 2015 October through 2016 December, using Swift, Spitzer and AstroLAB IRIS. The star faded in a manner similar to the long-term fading seen in Kepler data about 1400 days previously. The dimming rate for the entire period reported is 22.1+/-9.7mmag/yr in the Swift wavebands, with amounts of 21.0+/-4.5mmag in the ground-based B measurements, 14.0+/-4.5mmag in V, and 13.0+/-4.5 in R, and a rate of 5.0+/-1.2mmag/yr averaged over the two warm Spitzer bands. Although the dimming is small, it is seen at >~3{sigma} by three different observatories operating from the UV to the IR. The presence of long-term secular dimming means that previous spectral energy distribution models of the star based on photometric measurements taken years apart may not be accurate. We find that stellar models with Teff=7000-7100K and A_V_~0.73 best fit the Swift data from UV to optical. These models also show no excess in the near-simultaneous Spitzer photometry at 3.6 and 4.5{mu}m, although a longer wavelength excess from a substantial debris disk is still possible (e.g., as around Fomalhaut). The wavelength dependence of the fading favors a relatively neutral color (i.e., R_V_>~5, but not flat across all the bands) compared with the extinction law for the general interstellar medium (R_V_=3.1), suggesting that the dimming arises from circumstellar material.
- ID:
- ivo://CDS.VizieR/J/AJ/142/112
- Title:
- KIC photometric calibration
- Short Name:
- J/AJ/142/112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the photometric calibration and stellar classification methods used by the Stellar Classification Project to produce the Kepler Input Catalog (KIC). The KIC is a catalog containing photometric and physical data for sources in the Kepler mission field of view; it is used by the mission to select optimal targets. Four of the visible-light (g, r, i, z) magnitudes used in the KIC are tied to Sloan Digital Sky Survey magnitudes; the fifth (D51) is an AB magnitude calibrated to be consistent with Castelli & Kurucz (CK) model atmosphere fluxes. We derived atmospheric extinction corrections from hourly observations of secondary standard fields within the Kepler field of view.
- ID:
- ivo://CDS.VizieR/J/ApJ/831/11
- Title:
- KIC 9777062 RVs & asteroseismology in NGC6811
- Short Name:
- J/ApJ/831/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of an eccentric, partially eclipsing long-period (P=19.23 days) binary system KIC 9777062 that contains main-sequence stars near the turnoff of the intermediate-age open cluster NGC 6811. The primary is a metal-lined Am star with a possible convective blueshift to its radial velocities, and one star (probably the secondary) is likely to be a {gamma} Dor pulsator. The component masses are 1.603+/-0.006(stat.)+/-0.016(sys.) and 1.419+/-0.003+/-0.008M_{sun}_, and the radii are 1.744+/-0.004+/-0.002 and 1.544+/-0.002+/-0.002R_{sun}_. The isochrone ages of the stars are mildly inconsistent: the age from the mass-radius combination for the primary (1.05+/-0.05+/-0.09Gyr, where the last quote was systematic uncertainty from models and metallicity) is smaller than that from the secondary (1.21+/-0.05+/-0.15Gyr) and is consistent with the inference from the color-magnitude diagram (1.00+/-0.05Gyr). We have improved the measurements of the asteroseismic parameters {Delta}{nu} and {nu}_max_ for helium-burning stars in the cluster. The masses of the stars appear to be larger (or alternately, the radii appear to be smaller) than predicted from isochrones using the ages derived from the eclipsing stars. The majority of stars near the cluster turnoff are pulsating stars: we identify a sample of 28 {delta} Sct, 15 {gamma} Dor, and 5 hybrid types. We used the period-luminosity relation for high-amplitude {delta} Sct stars to fit the ensemble of the strongest frequencies for the cluster members, finding (m-M)_V_=10.37+/-0.03. This is larger than most previous determinations, but smaller than values derived from the eclipsing binary (10.47+/-0.05).
- ID:
- ivo://CDS.VizieR/J/ApJ/844/102
- Title:
- KIC star parallaxes from asteroseismology vs Gaia
- Short Name:
- J/ApJ/844/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comparison of parallaxes and radii from asteroseismology and Gaia DR1 (TGAS) for 2200 Kepler stars spanning from the main sequence to the red-giant branch. We show that previously identified offsets between TGAS parallaxes and distances derived from asteroseismology and eclipsing binaries have likely been overestimated for parallaxes <~5-10mas (~90%-98% of the TGAS sample). The observed differences in our sample can furthermore be partially compensated by adopting a hotter Teff scale (such as the infrared flux method) instead of spectroscopic temperatures for dwarfs and subgiants. Residual systematic differences are at the ~2% level in parallax across three orders of magnitude. We use TGAS parallaxes to empirically demonstrate that asteroseismic radii are accurate to ~5% or better for stars between ~0.8-8R_{sun}_. We find no significant offset for main- sequence (<~1.5R_{sun}_) and low-luminosity RGB stars (~3-8R_{sun}_), but seismic radii appear to be systematically underestimated by ~5% for subgiants (~1.5-3R_{sun}_). We find no systematic errors as a function of metallicity between [Fe/H]~-0.8 to +0.4dex, and show tentative evidence that corrections to the scaling relation for the large frequency separation ({Delta}{nu}) improve the agreement with TGAS for RGB stars. Finally, we demonstrate that beyond ~3kpc asteroseismology will provide more precise distances than end-of-mission Gaia data, highlighting the synergy and complementary nature of Gaia and asteroseismology for studying galactic stellar populations.
- ID:
- ivo://CDS.VizieR/II/347
- Title:
- KiDS-ESO-DR3 multi-band source catalog
- Short Name:
- II/347
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kilo-Degree Survey (KiDS) is an ongoing optical wide-field imaging survey with the OmegaCAM camera at the VLT Survey Telescope. It aims to image 1500 square degrees in four filters (ugri). The core science driver is mapping the large-scale matter distribution in the Universe, using weak lensing shear and photometric redshift measurements. Further science cases include galaxy evolution, Milky Way structure, detection of high-redshift clusters, and finding rare sources such as strong lenses and quasars. Here we present the third public data release (DR3) and several associated data products, adding further area, homogenized photometric calibration, photometric redshifts and weak lensing shear measurements to the first two releases. A dedicated pipeline embedded in the Astro-WISE information system is used for the production of the main release. Modifications with respect to earlier releases are described in detail. Photometric redshifts have been derived using both Bayesian template fitting, and machine-learning techniques. For the weak lensing measurements, optimized procedures based on the THELI data reduction and lensfit shear measurement packages are used. The multi-band catalogue, including homogenized photometry and photometric redshifts, covers the combined DR1, DR2 and DR3 footprint of 440 survey tiles (447deg^2^). Limiting magnitudes are typically 24.3, 25.1, 24.9, 23.8 (5 sigma in a 2 arcsec aperture) in ugri, respectively, and the typical r-band PSF size is less than 0.7 arcsec. The photometric homogenization scheme ensures accurate colors and an absolute calibration stable to ~2% for gri and ~3% in u. Separately released are a weak lensing shear catalogue and photometric redshifts based on two different machine-learning techniques.
- ID:
- ivo://CDS.VizieR/II/344
- Title:
- KiDS-ESO-DR2 multi-band source catalog
- Short Name:
- II/344
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Kilo-Degree Survey (KiDS) is an optical wide-field imaging survey carried out with the VLT Survey Telescope and the OmegaCAM camera. KiDS will image 1500 square degrees in four filters (ugri), and together with its near-infrared counterpart VIKING will produce deep photometry in nine bands. Designed for weak lensing shape and photometric redshift measurements, its core science driver is mapping the large-scale matter distribution in the Universe back to a redshift of ~0.5. Secondary science cases include galaxy evolution, Milky Way structure, and the detection of high-redshift clusters and quasars.
- ID:
- ivo://CDS.VizieR/J/ApJ/893/4
- Title:
- KiDS ultracompact massive galaxies sp. obs.
- Short Name:
- J/ApJ/893/4
- Date:
- 03 Dec 2021 00:37:06
- Publisher:
- CDS
- Description:
- Ultracompact massive galaxies (UCMGs), i.e., galaxies with stellar masses M_*_>8x10^10^M_{sun}_ and effective radii R_e_<1.5kpc, are very rare systems, in particular at low and intermediate redshifts. Their origin as well as their number density across cosmic time are still under scrutiny, especially because of the paucity of spectroscopically confirmed samples. We have started a systematic census of UCMG candidates within the ESO Kilo Degree Survey, together with a large spectroscopic follow-up campaign to build the largest possible sample of confirmed UCMGs. This is the third paper of the series and the second based on the spectroscopic follow-up program. Here, we present photometrical and structural parameters of 33 new candidates at redshifts 0.15<~z<~0.5 and confirm 19 of them as UCMGs, based on their nominal spectroscopically inferred M_*_ and R_e_. This corresponds to a success rate of ~58% , nicely consistent with our previous findings. The addition of these 19 newly confirmed objects allows us to fully assess the systematics on the system selection-and to finally reduce the number density uncertainties. Moreover, putting together the results from our current and past observational campaigns and some literature data, we build the largest sample of ucmgs ever collected, comprising 92 spectroscopically confirmed objects at 0.1<~z<~0.5. This number raises to 116, allowing for a 3{sigma} tolerance on the M_*_ and R_e_ thresholds for the ucmg definition. For all these galaxies, we have estimated the velocity dispersion values at the effective radii, which have been used to derive a preliminary mass-velocity dispersion correlation.
- ID:
- ivo://CDS.VizieR/J/A+A/633/A69
- Title:
- KiDS-VIKING-450 cosmic shear
- Short Name:
- J/A+A/633/A69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a tomographic cosmic shear analysis of the Kilo-Degree Survey (KiDS) combined with the VISTA Kilo-Degree Infrared Galaxy Survey (VIKING). This is the first time that a full optical to near-infrared data set has been used for a wide-field cosmological weak lensing experiment. This unprecedented data, spanning 450 deg^2^, allows us to significantly improve the estimation of photometric redshifts, such that we are able to include robustly higher-redshift sources for the lensing measurement, and - most importantly - to solidify our knowledge of the redshift distributions of the sources. Based on a flat LCDM model we find S_8_=0.737^+0.040^_-0.036_ in a blind analysis from cosmic shear alone. The tension between KiDS cosmic shear and the Planck Legacy CMB measurements remains in this systematically more robust analysis, with S_8_ differing by 2.3{sigma}. This result is insensitive to changes in the priors on nuisance parameters for intrinsic alignment, baryon feedback, and neutrino mass. KiDS shear measurements are calibrated with a new, more realistic set of image simulations and no significant B-modes are detected in the survey, indicating that systematic errors are under control. When calibrating our redshift distributions by assuming the 30-band COSMOS-2015 photometric redshifts are correct (following the Dark Energy Survey and the Hyper Suprime-Cam Survey), we find the tension with Planck is alleviated. The robust determination of source redshift distributions remains one of the most challenging aspects for future cosmic shear surveys. Data products from this analysis are available at http://kids.strw.leidenuniv.nl.
