Number of results to display per page
Search Results
- 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/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.
- ID:
- ivo://CDS.VizieR/J/AJ/132/714
- Title:
- QUEST RR Lyrae survey. II. Halo overdensities
- Short Name:
- J/AJ/132/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first catalog of the RR Lyrae stars (RRLSs) in the Galactic halo by the Quasar Equatorial Survey Team (QUEST) has been searched for significant overdensities that may be debris from disrupted dwarf galaxies or globular clusters. These RRLSs are contained in a band 23 wide in declination that spans 165{deg} in right ascension and lie 4 to 60kpc from the Sun. Away from the major overdensities, the distribution of these stars is adequately fitted by a smooth halo model, in which the flattening of the halo decreases with increasing galactocentric distance (as reported by Preston et al., 1991ApJ...375..121P). This model was used to estimate the background of RRLSs on which the halo overdensities are overlaid. A procedure was developed for recognizing groups of stars that constitute significant overdensities with respect to this background. To test this procedure, a Monte Carlo routine was used to make artificial RRLS surveys that follow the smooth halo model but with Poissondistributed noise in the numbers of RRLSs and, within limits, random variations in the positions and magnitudes of the artificial stars. The 104 artificial surveys created by this routine were examined for significant groups in exactly the same way as the QUEST survey.
- ID:
- ivo://CDS.VizieR/J/MNRAS/427/3374
- Title:
- QUEST RR Lyrae Survey III. Low Galactic latitude
- Short Name:
- J/MNRAS/427/3374
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results for the QUEST RR Lyrae Survey at low Galactic latitude, conducted entirely with observations obtained with the QUEST mosaic camera and the 1.0/1.5-m Jurgen Stock Schmidt telescope at the National Observatory of Venezuela. The survey spans an area of 476deg^2^ on the sky, with multi-epoch observations in the V, R and I photometric bands for 6.5x10^6^ stars in the Galactic latitude range -30{deg}<=b<=+25{deg}, in a direction close to the Galactic anticentre 190{deg}<=l<=230{deg}. The variability survey has a typical number of 30 observations per object in V and I and ~25 in R, with up to ~120-150 epochs in V and I and up to ~100 in R in the best sampled regions. The completeness magnitudes of the survey are V=R=18.5mag, and I=18.0mag. We identified 211 RR Lyrae stars, 160 bona fide stars of type ab and 51 candidates of type c, ours being the first deep RR Lyrae survey conducted at low Galactic latitude, in the Galactic disc. The completeness of the RR Lyrae survey was estimated in >~95 and ~85 per cent for RRab and RRc stars, respectively. Photometric metallicities were computed based on the light curves and individual extinctions calculated from minimum light colours for each RRab star. Distances were obtained with typical errors ~7 per cent. The RR Lyrae survey simultaneously spans a large range of heliocentric distances 0.5<=R_hel_(kpc)<=40 and heights above the plane -15<=z(kpc)<=+20, with well-known completeness across the survey area, making it an ideal set for studying the structure of the Galactic thick disc.
- ID:
- ivo://CDS.VizieR/II/296
- Title:
- QUEST1 variability survey (QVS). III.
- Short Name:
- II/296
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports an update to the QUEST1 (QUasar Equatorial Survey Team, Phase 1) Variability Survey (QVS) light curve catalog, which links QVS instrumental Light curve magnitude at jdlight curves to Sloan Digital Sky Survey (SDSS) objects and photometry. In the time since the original QVS catalog release, the overlap between publicly available SDSS data and QVS data has increased by 8% in sky coverage and 16728 in number of matched objects. The astrometric matching and the treatment of SDSS masks have been refined for the updated catalog. We report on these improvements and present multiple bandpass light curves, global variability information, and matched SDSS photometry for 214941 QUEST1 objects.
738. RACE-OC project. II.
- ID:
- ivo://CDS.VizieR/J/A+A/532/A10
- Title:
- RACE-OC project. II.
- Short Name:
- J/A+A/532/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Rotational properties of late-type low-mass members of associations of known age provide a fundamental source of information on stellar internal structure and its evolution. We aim at determining the rotational and magnetic-related activity properties of stars at different stages of evolution. We focus our attention primarily on members of young stellar associations of known ages. Specifically, we extend our previous analysis in Paper I (Messina et al., 2010, Cat. J/A+A/520/A15) to 3 additional young stellar associations beyond 100pc and with ages in the range 6-40Myr: {epsilon} Chamaeleontis (~6Myr), Octans (~20Myr), and Argus (~40Myr). Additional rotational data of {eta} Chamaeleontis and IC 2391 clusters are also considered. Rotational periods were determined by applying the Lomb-Scargle periodogram technique to photometric time-series data obtained by the All Sky Automated Survey (ASAS) and the Wide Angle Search for Planets (SuperWASP) archives. The magnetic activity level was derived from the amplitude of the V light curves.
- ID:
- ivo://CDS.VizieR/J/A+A/520/A15
- Title:
- RACE-OC project: YSOs within 100pc
- Short Name:
- J/A+A/520/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Examining the angular momentum of stars and its interplay with their magnetic fields represent a promising way to probe the stellar internal structure and evolution of low-mass stars. We attempt to determine the rotational and magnetic-related activity properties of stars at different stages of evolution.We focused our attention primarily on members of clusters and young stellar associations of known ages. In this study, our targets are 6 young loose stellar associations within 100pc and with ages in the range 8-70Myr: TW Hydrae (~8Myr), beta Pictoris (~10Myr), Tucana/Horologium, Columba, Carina (~30Myr), and AB Doradus (~70Myr). Additional rotational data for alpha Persei and the Pleiades from the literature are also considered.
- ID:
- ivo://CDS.VizieR/J/PASP/122/1285
- Title:
- Radial-velocities of 20 cataclysmic var.
- Short Name:
- J/PASP/122/1285
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained time-series radial-velocity spectroscopy of 20 cataclysmic variable stars, with the aim of determining orbital periods P_orb_. All of the stars reported here prove to have P_orb>_3.5h. For 16 of the stars, these are the first available period determinations, and for the remaining four (V709 Cas, AF Cam, V1062 Tau, and RX J2133+51), we use new observations to improve the accuracy of previously published periods. Most of the targets are dwarf novae, without notable idiosyncrasies.
