- ID:
- ivo://CDS.VizieR/VII/228
- Title:
- Las Campanas Infrared Survey
- Short Name:
- VII/228
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Las Campanas Infrared Survey, based on broadband optical and near-infrared photometry, is designed to robustly identify a statistically significant and representative sample of evolved galaxies at redshifts z>1. We have completed an H-band imaging survey over 1.1{deg}^2^ of sky in six separate fields. The average 5{sigma} detection limit in a 4" diameter aperture is H~20.8. Here we describe the design of the survey, the observation strategies, data-reduction techniques, and object identification procedures. We present sample near-infrared and optical photometric catalogs for objects identified in two survey fields. The optical images of the Hubble Deep Field-South region obtained from the literature reach 5{sigma} detection thresholds in a 4" diameter aperture of U~24.6, B~26.1, V~25.6, R~25.1, and I~24.2mag. The optical images of the Chandra Deep Field-South region obtained from our own observations reach 5 {sigma} detection thresholds in a 4" diameter aperture of V~26.8, R~26.2, I~25.3, and z'~23.7mag. We perform object detection in all bandpasses and identify>~54000 galaxies over 1408 arcmin^2^ of sky in the two fields. Of these galaxies, ~14000 are detected in the H band and ~2000 have the colors of evolved galaxies, I-H >~3, at z>~1.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/162/102
- Title:
- LASSO; Robo-AO observation of 444 young stars
- Short Name:
- J/AJ/162/102
- Date:
- 14 Mar 2022 06:43:15
- Publisher:
- CDS
- Description:
- We present results from the Large Adaptive optics Survey for Substellar Objects, where the goal is to directly image new substellar companions (<70M_Jup_) at wide orbital separations (>~50au) around young (<~300Myr), nearby (<100pc), low-mass (~0.1-0.8 M{odot}) stars. We report on 427 young stars imaged in the visible (i') and near-infrared (J or H ) simultaneously with Robo-AO on the Kitt Peak 2.1m telescope and later the Maunakea University of Hawaii 2.2m telescope. To undertake the observations, we commissioned a new infrared camera for Robo-AO that uses a low-noise high-speed SAPHIRA avalanche photodiode detector. We detected 121 companion candidates around 111 stars, of which 62 companions are physically associated based on Gaia DR2 parallaxes and proper motions, another 45 require follow-up observations to confirm physical association, and 14 are background objects. The companion separations range from 2 to 1101 au and reach contrast ratios of 7.7 mag in the near-infrared compared to the primary. The majority of confirmed and pending candidates are stellar companions, with ~5 being potentially substellar and requiring follow-up observations for confirmation. We also detected a 43{+/-}9 M_Jup_ and an 81{+/-}5M_Jup_ companion that were previously reported. We found 34 of our targets have acceleration measurements detected using Hipparcos-Gaia proper motions. Of those, 58_-14_^+12^% of the 12 stars with imaged companion candidates have significant accelerations ({chi}^2^>11.8), while only 23_-6_^+11^% of the remaining 22 stars with no detected companion have significant accelerations. The significance of the acceleration decreases with increasing companion separation. These young accelerating low-mass stars with companions will eventually yield dynamical masses with future orbit monitoring.
- ID:
- ivo://CDS.VizieR/J/AJ/107/1556
- Title:
- Late B-type stars classification
- Short Name:
- J/AJ/107/1556
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the fourth and final of a series of papers on the late B to the early F type stars, we refine the MK spectral classification system for the late B type stars and consider the effect of rotation on both spectral classification and Stromgren photometry of these stars. We extend the work of Morgan by establishing self-consistent sequences of narrow and broadlined standards. We reclassify a number of Bp stars, compare these classifications with Stromgren photometry and consider the question of whether all Bp stars are main-sequence objects.
- ID:
- ivo://CDS.VizieR/J/A+A/442/281
- Title:
- Late-type giants BVRIJHKL and Teff calibration
- Short Name:
- J/A+A/442/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new synthetic broad-band photometric colors for late-type giants based on synthetic spectra calculated with the PHOENIX model atmosphere code. The grid covers effective temperatures Teff=3000...5000K, gravities logg=-0.5...+3.5, and metallicities [M/H]=+0.5...-4.0.
- ID:
- ivo://CDS.VizieR/J/MNRAS/328/45
- Title:
- Late-type stars members of young groups
- Short Name:
- J/MNRAS/328/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the first paper of a series aimed at studying the properties of late-type members of young stellar kinematic groups. We concentrate our study on classical young moving groups such as the Local Association (Pleiades moving group, 2-150Myr), IC 2391 supercluster (35Myr), Ursa Major group (Sirius supercluster, 300Myr), and Hyades supercluster (600Myr), as well as on recently identified groups such as the Castor moving group (200Myr). In this paper we compile a preliminary list of single late-type possible members of some of these young stellar kinematic groups. Stars are selected from previously established members of stellar kinematic groups based on photometric and kinematic properties as well as from candidates based on other criteria such as their level of chromospheric activity, rotation rate and lithium abundance. Precise measurements of proper motions and parallaxes taken from the Hipparcos Catalogue, as well as from the Tycho-2 Catalogue, and published radial velocity measurements are used to calculate the Galactic space motions (U, V, W) and to apply Eggen's kinematic criteria in order to determine the membership of the selected stars to the different groups.
- ID:
- ivo://CDS.VizieR/J/PASP/111/1169
- Title:
- Late-type stars toward galactic antirotation
- Short Name:
- J/PASP/111/1169
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Low-resolution objective-prism spectra (1360{AA}/mm at H{gamma}) of 184 late-type stars in the Galactic antirotation direction have been obtained with the Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory. The stars have been classified into three groups: F6-G2, G3-K0, and K1-M8. Subsequent observations on the BV and DDO systems have been obtained. The correlation between the thin-prism classes and the DDO classes is as expected, with no significant systematic differences of note. A comparison of Guide Star Catalog magnitudes, corrected to V, is also made, with favorable results. The stars in this list are expected to be useful for studying the structure and star formation history of the Milky Way.
- ID:
- ivo://CDS.VizieR/J/MNRAS/317/801
- Title:
- LBDS Hercules sample griJHK photometry
- Short Name:
- J/MNRAS/317/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results are presented of an extensive programme of optical and infrared imaging of radio sources in a complete subsample of the Leiden-Berkeley Deep Survey. The LBDS Hercules sample consists of 72 sources observed at 1.4GHz, with flux densities S_1.4_>=1.0mJy, in a 1.2deg^2^ region of Hercules. This sample is almost completely identified in the g, r, i and K bands, with some additional data available at J and H. The magnitude distributions peak at r~22mag, K~6mag and extend down to r~26mag, K~21mag. The K-band magnitude distributions for the radio galaxies and quasars are compared with those of other radio surveys. At S_1.4GHz_<~1Jy, the K-band distribution does not change significantly with radio flux density. The sources span a broad range of colours, with several being extremely red (r-K>~6). Though small, this is the most optically complete sample of mJy radio sources available at 1.4GHz, and is ideally suited for studying the evolution of the radio luminosity function out to high redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/809/42
- Title:
- LC and RV data of PTFO 8-8695 T-Tauri star
- Short Name:
- J/ApJ/809/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Spitzer 4.5{mu}m light curve observations, Keck NIRSPEC radial velocity observations, and LCOGT optical light curve observations of PTFO 8-8695, which may host a Jupiter-sized planet in a very short orbital period (0.45 days). Previous work by van Eyken et al. (2012ApJ...755...42V) and Barnes et al. (2013ApJ...774...53B) predicts that the stellar rotation axis and the planetary orbital plane should precess with a period of 300-600 days. As a consequence, the observed transits should change shape and depth, disappear, and reappear with the precession. Our observations indicate the long-term presence of the transit events (>3 years), and that the transits indeed do change depth, disappear and reappear. The Spitzer observations and the NIRSPEC radial velocity observations (with contemporaneous LCOGT optical light curve data) are consistent with the predicted transit times and depths for the M*=0.34M_{sun}_ precession model and demonstrate the disappearance of the transits. An LCOGT optical light curve shows that the transits do reappear approximately 1 year later. The observed transits occur at the times predicted by a straight-forward propagation of the transit ephemeris. The precession model correctly predicts the depth and time of the Spitzer transit and the lack of a transit at the time of the NIRSPEC radial velocity observations. However, the precession model predicts the return of the transits approximately 1 month later than observed by LCOGT. Overall, the data are suggestive that the planetary interpretation of the observed transit events may indeed be correct, but the precession model and data are currently insufficient to confirm firmly the planetary status of PTFO 8-8695b.
- ID:
- ivo://CDS.VizieR/J/AJ/159/261
- Title:
- LC of microlensing event OGLE-2012-BLG-0838
- Short Name:
- J/AJ/159/261
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present the discovery of a planet on a very wide orbit in the microlensing event OGLE-2012-BLG-0838. The signal of the planet is well separated from the main peak of the event and the planet-star projected separation is found to be twice the Einstein ring radius, which corresponds to a projected separation of ~4au. Similar planets around low-mass stars are very hard to find using any technique other than microlensing. We discuss microlensing model fitting in detail and discuss the prospects for measuring the mass and distance of the lens system directly.
1870. LC of the TNO Varuna
- ID:
- ivo://CDS.VizieR/J/ApJ/883/L21
- Title:
- LC of the TNO Varuna
- Short Name:
- J/ApJ/883/L21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From CCD observations carried out with different telescopes, we present short-term photometric measurements of the large trans-Neptunian object Varuna in 10 epochs, spanning around 19 years. We observe that the amplitude of the rotational light curve has changed considerably during this period of time from 0.41 to 0.55mag. In order to explain this variation, we constructed a model in which Varuna has a simple triaxial shape, assuming that the main effect comes from the change of the aspect angle as seen from Earth, due to Varuna's orbital motion in the 19yr time span. The best fits to the data correspond to a family of solutions with axial ratios b/a between 0.56 and 0.60. This constrains the pole orientation in two different ranges of solutions presented here as maps. Apart from the remarkable variation of the amplitude, we have detected changes in the overall shape of the rotational light curve over shorter timescales. After the analysis of the periodogram of the residuals to a 6.343572hr double-peaked rotational light-curve fit, we find a clear additional periodicity. We propose that these changes in the rotational light-curve shape are due to a large and close-in satellite whose rotation induces the additional periodicity. The peak-to-valley amplitude of this oscillation is in the order of 0.04mag. We estimate that the satellite orbits Varuna with a period of 11.9819hr (or 23.9638hr), assuming that the satellite is tidally locked, at a distance of ~1300km (or ~2000km) from Varuna, outside the Roche limit.
