- ID:
- ivo://CDS.VizieR/J/AJ/156/186
- Title:
- The High Cadence Transit Survey (HiTS)
- Short Name:
- J/AJ/156/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ~15 million object detections and a catalog of ~2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one {delta} Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate.
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- ID:
- ivo://CDS.VizieR/J/ApJ/844/78
- Title:
- The high-redshift COBRA survey: IRAC obs.
- Short Name:
- J/ApJ/844/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the Very Large Array FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey to a limit of m_r_=22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z=1 and extends out to z~3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (>=2{sigma}) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the >=2{sigma} limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2{sigma} cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/40
- Title:
- The HIPASS Catalog (HICAT) + WISE galaxies
- Short Name:
- J/ApJ/864/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the relationships between HI mass, stellar mass, and star formation rate using the HI Parkes All-Sky Survey Catalog (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3513 HICAT sources, we find 3.4{mu}m counterparts for 2896 sources (80%), and provide new WISE-matched aperture photometry for these galaxies. For our principal sample of spiral galaxies with W1<=10mag and z<=0.01, we identify HI detections for 93% of the sample. We measure lower HI-stellar mass relationships for HI-selected samples that do not include spiral galaxies with little HI gas. Our observations of the spiral sample show that HI mass increases with stellar mass with a power-law index of 0.35; however, this value is dependent on T-type, which affects both the median and the dispersion of HI mass. We also observe an upper limit on the HI gas fraction, which is consistent with a halo spin parameter model. We measure the star formation efficiency of spiral galaxies to be constant at 10^-9.57^yr^-1^+/-0.4dex for 2.5 orders of magnitude in stellar mass, despite the higher stellar mass spiral showing evidence of quenched star formation.
- ID:
- ivo://CDS.VizieR/I/239
- Title:
- The Hipparcos and Tycho Catalogues
- Short Name:
- I/239
- Date:
- 18 Nov 2021 11:08:10
- Publisher:
- CDS
- Description:
- The Hipparcos and Tycho Catalogues are the primary products of the European Space Agency's astrometric mission, Hipparcos. The satellite, which operated for four years, returned high quality scientific data from November 1989 to March 1993. Each of the catalogues contains a large quantity of very high quality astrometric and photometric data. In addition there are associated annexes featuring variability and double/multiple star data, and solar system astrometric and photometric measurements. In the case of the Hipparcos Catalogue, the principal parts are provided in both printed and machine-readable form (on CDROM). In the case of the Tycho Catalogue, results are provided in machine-readable form only (on CDROM). Although in general only the final reduced and calibrated astrometric and photometric data are provided, some auxiliary files containing results from intermediate stages of the data processing, of relevance for the more-specialised user, have also been retained for publication. (Some, but not all, data files are available from the Centre de Donnees astronomiques de Strasbourg.) The global data analysis tasks, proceeding from nearly 1000 Gbit of raw satellite data to the final catalogues, was a lengthy and complex process, and was undertaken by the NDAC and FAST Consortia, together responsible for the production of the Hipparcos Catalogue, and the Tycho Consortium, responsible for the production of the Tycho Catalogue. A fourth scientific consortium, the INCA Consortium, was responsible for the construction of the Hipparcos observing programme, compiling the best-available data for the selected stars before launch into the Hipparcos Input Catalogue. The production of the Hipparcos and Tycho Catalogues marks the formal end of the involvement in the mission by the European Space Agency and the four scientific consortia. For more complete and detailed information on the data, the user is advised to refer to Volume 1 ("Introduction and Guide to the Data", ESA SP-1200) of the printed Hipparcos and Tycho Catalogues. The user should also note that in order to convert the Double and Multiple Systems (Component solutions) data file hip_dm_c.dat into FITS format it is first necessary to filter the file according to whether the entry is a component record (identified by COMP in field DCM5) or a correlation record (identified by CORR in field DCM5) because of the different structures of the respective records. On a Unix system this can be achieved as follows: grep COMP hip_dm_c.dat > h_dm_com.dat grep CORR hip_dm_c.dat > h_dm_cor.dat The catalogue description file (this file) gives the relevant information for converting the main data files, including h_dm_cor.dat and h_dm_com.dat, into FITS format. The machine readable data files (i.e. those available on CD-ROM and the subset available from the CDS) contain several extra fields in addition to the data from the printed catalogue. These fields are identified by the letter `M' in the data label (e.g. the field DGM1 contains data only available in the machine readable file hip_dm_g.dat).
- ID:
- ivo://CDS.VizieR/J/ApJ/788/92
- Title:
- The hot Jupiter Kepler-13Ab planet's occultation
- Short Name:
- J/ApJ/788/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations observed by warm Spitzer at 4.5 {mu}m and 3.6 {mu}m and a ground-based occultation observation in the K_s_ band (2.1 {mu}m). We derive a day-side hemisphere temperature of 2750+/-160 K as the effective temperature of a black body showing the same occultation depths. Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion. Our analysis shows evidence for a relatively high geometric albedo, A_g_=0.33_-0.06_^+0.04^. While measured with a simplistic method, a high A_g_ is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical. We use stellar spectra to determine the dilution, in the four wide bands where occultation was measured, due to the visual stellar binary companion 1.15"+/-0.05" away. The revised stellar parameters measured using these spectra are combined with other measurements, leading to revised planetary mass and radius estimates of M_p_=4.94-8.09 M_J_ and R_p_=1.406+/-0.038 R_J_. Finally, we measure a Kepler midoccultation time that is 34.0+/-6.9 s earlier than expected based on the midtransit time and the delay due to light-travel time and discuss possible scenarios.
- ID:
- ivo://CDS.VizieR/J/ApJ/746/85
- Title:
- THe HST Cluster Supernova Survey. V.
- Short Name:
- J/ApJ/746/85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Advanced Camera for Surveys, NICMOS, and Keck adaptive-optics-assisted photometry of 20 Type Ia supernovae (SNe Ia) from the Hubble Space Telescope (HST) Cluster Supernova Survey. The SNe Ia were discovered over the redshift interval 0.623<z<1.415. Of these SNe Ia, 14 pass our strict selection cuts and are used in combination with the world's sample of SNe Ia to derive the best current constraints on dark energy. Of our new SNe Ia, 10 are beyond redshift z = 1, thereby nearly doubling the statistical weight of HST-discovered SNe Ia beyond this redshift. Our detailed analysis corrects for the recently identified correlation between SN Ia luminosity and host galaxy mass and corrects the NICMOS zero point at the count rates appropriate for very distant SNe Ia. Adding these SNe improves the best combined constraint on dark-energy density, {rho}_DE_(z), at redshifts 1.0<z<1.6 by 18% (including systematic errors).
- ID:
- ivo://CDS.VizieR/J/A+A/630/A92
- Title:
- The Hubble Catalog of Variables
- Short Name:
- J/A+A/630/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Hubble Catalog of Variables (HCV) is the first full, homogeneous, catalog of variable sources found in the Hubble Source Catalog (HSC), which is built out of publicly available images obtained with the WFPC2, ACS and WFC3 instruments onboard the Hubble Space Telescope. The HCV is the deepest catalog of variables available. It includes variable stars in our Galaxy and nearby galaxies, as well as transients and variable active galactic nuclei. The HCV contains 84428 candidate variable sources (out of 3.7 million HSC sources that were searched for variability) with V<=27mag; for 11115 of them the variability is detected in more than one filter. The data points in a light curve range from 5 to 120, the time baseline ranges from under a day to over 15 years, while ~8% of variables have amplitudes in excess of 1mag.
- ID:
- ivo://CDS.VizieR/I/324
- Title:
- The Initial Gaia Source List (IGSL)
- Short Name:
- I/324
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Initial Gaia Source List will be the starting point for the Gaia Initial Data Treatment. The Attitude Star Catalog will be used by the first iteration of the on-ground attitude reconstruction.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A9
- Title:
- The International Deep Planet Survey. I.
- Short Name:
- J/A+A/544/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence of massive planets at relatively large separations, but dedicated surveys are required to estimate the frequency of similar planetary systems. To measure the first estimation of the giant exoplanetary systems frequency at large orbital separation around A-stars, we have conducted a deep-imaging survey of young (8-400Myr), nearby (19-84pc) A- and F-stars to search for substellar companions in the ~10-300AU range. The sample of 42 stars combines all A-stars observed in previous AO planet search surveys reported in the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It represents an initial subset of the International Deep Planet Survey (IDPS) sample of stars covering M- to B-stars. The data were obtained with diffraction-limited observations in H- and Ks-band combined with angular differential imaging to suppress the speckle noise of the central stars, resulting in typical 5-sigma detection limits in magnitude difference of 12mag at 1", 14mag at 2" and 16mag at 5" which is sufficient to detect massive planets. A detailed statistical analysis of the survey results is performed using Monte Carlo simulations. Considering the planet detections, we estimate the fraction of A-stars having at least one massive planet (3-14M_Jup_) in the range 5-320AU to be inside 5.9-18.8% at 68% confidence, assuming a flat distribution for the mass of the planets. By comparison, the brown dwarf (15-75M_Jup_) frequency for the sample is 2.0-8.9% at 68% confidence in the range 5-320AU. Assuming power law distributions for the mass and semimajor axis of the planet population, the AO data are consistent with a declining number of massive planets with increasing orbital radius which is distinct from the rising slope inferred from radial velocity (RV) surveys around evolved A-stars and suggests that the peak of the massive planet population around A-stars may occur at separations between the ranges probed by existing RV and AO observations. Finally, we report the discovery of three new close M-star companions to HIP 104365 and HIP 42334.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/196
- Title:
- The invisible AGN catalogue
- Short Name:
- J/MNRAS/468/196
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A large fraction of active galactic nuclei (AGN) are 'invisible' in extant optical surveys due to either distance or dust-obscuration. The existence of this large population of dust-obscured, infrared (IR)-bright AGN is predicted by models of galaxy-supermassive black hole coevolution and is required to explain the observed X-ray and IR backgrounds. Recently, IR colour cuts with Wide-field Infrared Survey Explorer have identified a portion of this missing population. However, as the host galaxy brightness relative to that of the AGN increases, it becomes increasingly difficult to differentiate between IR emission originating from the AGN and from its host galaxy. As a solution, we have developed a new method to select obscured AGN using their 20-cm continuum emission to identify the objects as AGN. We created the resulting invisible AGN catalogue by selecting objects that are detected in AllWISE (mid-IR) and FIRST (20 cm), but are not detected in SDSS (optical) or 2MASS (near-IR), producing a final catalogue of 46 258 objects. 30 per cent of the objects are selected by existing selection methods, while the remaining 70 per cent represent a potential previously unidentified population of candidate AGN that are missed by mid-IR colour cuts. Additionally, by relying on a radio continuum detection, this technique is efficient at detecting radio-loud AGN at z>=0.29, regardless of their level of dust obscuration or their host galaxy's relative brightness.
