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- ID:
- ivo://CDS.VizieR/J/A+AS/127/367
- Title:
- Virgo Photometry Catalogue (VPC)
- Short Name:
- J/A+AS/127/367
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Virgo Photometry Catalogue (VPC) contains independently calibrated surface photometry in the U, B_J_ and R_C_ bands for over 1000 galaxies (including background objects) brighter than B_J25_=19.0 in a 23{deg}^2^ area of the sky centred on R.A., Dec.(1950)= 12h26m, +13{deg}08'. The angular resolution of the photometry varies from band to band and was in each case determined from the FWHM of stellar profiles: 4.75+/-0.1arcsec in the U band, 5.0+/-0.1arcsec in the B_J_ band and 6.0+/-0.1arcsec in the R_C_ band. The photometry was intended for the derivation of accurate magnitudes and colours and is therefore not of high resolution. Stellar contamination of the galaxy sample is minimal, and cannot exceed about 3 faint-end objects in total (i.e. it is less than about 0.25%). Parameters listed for catalogued galaxies include: equatorial coordinates; morphological types; surface-brightness profile parameters (which preserve the majority of the surface photometry information); U, B_J_ and R_C_ isophotal magnitudes; U, B_J_, R_C_ and [transformed] B total magnitudes; (U-B_J_) and (B_J_-R_C_) equal-area colours, apparent angular radii, ellipticities, position angles, heliocentric radial velocities and alternative designations. All total magnitudes and total colours are extrapolated according to the "t" system of Young et al. (1998A&AS..130..173Y). The VPC is based primarily on four UK-Schmidt plates, all of which were scanned using the COSMOS measuring machine at the Royal Observatory Edinburgh. All magnitudes, colours and surface-brightness parameters are derived from numerical integrations of segmented plate-scan data; except for (in 109 cases) saturated and (in 51 cases) inextricably merged images. The latter 51 images are listed in Table 14 (Appendix D) of the original paper, whilst data for the remaining 1129 objects [i.e. including ones for which the VPC photometry is saturated in one or more bands] are listed in the main catalogue.
- ID:
- ivo://CDS.VizieR/J/other/NewA/38.50
- Title:
- VIr light curves of GK Aqr
- Short Name:
- J/other/NewA/38.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We made the first VRI CCD light curves of the short-period contact eclipsing binary GK Aqr, which was observed on October 5 and 8, 2013 at Xinglong station of National Astronomical Observatories, China. The ephemeris of GK Aqr was calculated based on our two newly obtained minima and the minima that other observers obtained previously. We discovered that the orbital period of GK Aqr exhibits an increasing trend of dP/dt=2.8(0.1)x10^-7^days/year by means of fitting the O-C values of the minima. This phenomenon might be explained by mass transfer from the primary (less massive) component to the secondary (more massive) one. With the updated Wilson & Devinney (1971ApJ...166..605W) program, we obtained the photometric orbital parameters for the first time. Using our parameters, we also successfully explained the light curve obtained from the All Sky Automated Survey data. In the end, we concluded that GK Aqr is a near contact binary with a low contact factor of 5.2%. As the mass transfer continues, GK Aqr could become a contact system and evolve into an over-contact system.
- ID:
- ivo://CDS.VizieR/II/286
- Title:
- VIRMOS deep imaging survey. VVDS-F02 catalog
- Short Name:
- II/286
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Franco-Italian VIRMOS project has delivered the VIMOS spectrograph for the European Southern Observatory Very Large Telescope (ESO-VLT). VIMOS is a VIsible imaging Multi-Object Spectrograph with outstanding multiplex capabilities: with 10 arcsec slits, spectra can be taken of 600 objects simultaneously. In integral field mode, a 6400-fibre Integral Field Unit (IFU) provides spectroscopy for all objects covering a 54x54arcsec^2^ area.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A65
- Title:
- VISION II. VISTA Orion A survey
- Short Name:
- J/A+A/614/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have investigated the shape of the extinction curve in the infrared up to ~25{mu}m for the Orion A star-forming complex. The basis of this work is near-infrared data acquired with the Visual and Infrared Survey Telescope for Astronomy, in combination with Pan-STARRS and mid-infrared Spitzer photometry. We obtain colour excess ratios for eight passbands by fitting a series of colour-colour diagrams. The fits are performed using Markov chain Monte Carlo methods, together with a linear model under a Bayesian formalism. The resulting colour excess ratios are directly interpreted as a measure of the extinction law. We show that the Orion A molecular cloud is characterized by flat mid-infrared extinction, similar to many other recently studied sightlines. Moreover, we find statistically significant evidence that the extinction law from ~1{mu}m to at least ~6{mu}m varies across the cloud. In particular, we find a gradient along galactic longitude, where regions near the Orion Nebula Cluster show a different extinction law compared to L1641 and L1647, the low-mass star-forming sites in the cloud complex. These variations are of the order of only 3% and are most likely caused by the influence of the massive stars on their surrounding medium. While the observed general trends in our measurements are in agreement with model predictions, both well-established and new dust grain models are not able to fully reproduce our infrared extinction curve. We also present a new extinction map featuring a resolution of 1' and revisit the correlation between extinction and dust optical depth. This analysis shows that cloud substructure, which is not sampled by background sources, affects the conversion factor between these two measures. In conclusion, we argue that specific characteristics of the infrared extinction law are still not well understood, but Orion A can serve as an unbiased template for future studies.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A153
- Title:
- VISION I. VISTA Orion A Survey
- Short Name:
- J/A+A/587/A153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Orion A hosts the nearest massive star factory, thus offering a unique opportunity to resolve the processes connected with the formation of both low- and high-mass stars. Here we present the most detailed and sensitive near-infrared (NIR) observations of the entire molecular cloud to date. With the unique combination of high image quality, survey coverage, and sensitivity, our NIR survey of Orion A aims at establishing a solid empirical foundation for further studies of this important cloud. In this first paper we present the observations, data reduction, and source catalog generation. To demonstrate the data quality, we present a first application of our catalog to estimate the number of stars currently forming inside Orion A and to verify the existence of a more evolved young foreground population. We used the European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) to survey the entire Orion A molecular cloud in the NIR J, H, and K_S_ bands, covering a total of ~18.3deg^2^. We implemented all data reduction recipes independently of the ESO pipeline. Estimates of the young populations toward Orion A are derived via the K_S_-band luminosity function. Our catalog (799995 sources) increases the source counts compared to the Two Micron All Sky Survey by about an order of magnitude. The 90% completeness limits are 20.4, 19.9, and 19.0mag in J, H, and K_S_, respectively. The reduced images have 20% better resolution on average compared to pipeline products. We find between 2300 and 3000 embedded objects in Orion A and confirm that there is an extended foreground population above the Galactic field, in agreement with previous work. The Orion A VISTA catalog represents the most detailed NIR view of the nearest massive star-forming region and provides a fundamental basis for future studies of star formation processes toward Orion.
- ID:
- ivo://CDS.VizieR/J/MNRAS/503/2265
- Title:
- VISTA and Subaru/HSC obs. of Upper Scorpius
- Short Name:
- J/MNRAS/503/2265
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim at identifying very low-mass isolated planetary-mass member candidates in the nearest OB association to the Sun, Upper Scorpius (145pc; 5-10Myr), to constrain the form and shape of the luminosity function and mass spectrum in this regime. We conducted a deep multi-band (Y=21.2, J=20.5, Z=22.0mag) photometric survey of six square degrees in the central region of Upper Scorpius. We extend the current sequence of astrometric and spectroscopic members by about two magnitudes in Y and one magnitude in J, reaching potentially T-type free-floating members in the association with predicted masses below 5 Jupiter masses, well into the planetary-mass regime. We extracted a sample of 57 candidates in this area and present infrared spectroscopy confirming two of them as young L-type members with characteristic spectral features of 10Myr-old brown dwarfs. Among the 57 candidates, we highlight 10 new candidates fainter than the coolest members previously confirmed spectroscopically. We do not see any obvious sign of decrease in the mass spectrum of the association, suggesting that star processes can form substellar objects with masses down to 4-5 Jupiter masses.
- ID:
- ivo://CDS.VizieR/III/334
- Title:
- VISTA Deep Extragalactic Observations (VIDEO)
- Short Name:
- III/334
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- VIDEO is a ~12 square degrees survey in the near-infrared Z, Y, J, H and Ks bands,over the ELAIS-S1, XMMLS, and ECDFS extragalactic fields. This document describes the catalog released for the deep stracked data in the VIDEO-XMM3 field, which also covers the Canada-France-Hawaii Telescope Legacy Survey Deep-1 field (CFHTLS-D1).
- ID:
- ivo://CDS.VizieR/J/ApJ/754/30
- Title:
- VISTA IR photometry of {sigma} Ori cluster
- Short Name:
- J/ApJ/754/30
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on our analysis of the VISTA Orion ZY JHK_s_ photometric data (completeness magnitudes of Z=22.6 and J=21.0 mag) focusing on a circular area of 2798.4arcmin^2^ around the young {sigma} Orionis star cluster (~3Myr, ~352pc, and solar metallicity). The combination of the VISTA photometry with optical, WISE and Spitzer data allows us to identify a total of 210 {sigma} Orionis member candidates with masses in the interval 0.25-0.004M_{sun}_, 23 of which are new planetary-mass object findings. These discoveries double the number of cluster planetary-mass candidates known so far. One object has colors compatible with a T spectral type. The {sigma} Orionis cluster harbors about as many brown dwarfs (69, 0.072-0.012M_{sun}_) and planetary-mass objects (37, 0.012-0.004M_{sun}_) as very low mass stars (104, 0.25-0.072M_{sun}_). Based on Spitzer data, we derive a disk frequency of ~40% for very low mass stars, brown dwarfs, and planetary-mass objects in {sigma} Orionis. The radial density distributions of these three mass intervals are alike: all are spatially concentrated within an effective radius of 12' (1.2pc) around the multiple star {sigma} Ori, and no obvious segregation between disk-bearing and diskless objects is observed.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/L20
- Title:
- VISTA KS photometry of EWS 2012-BLG-548
- Short Name:
- J/ApJ/810/L20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the discovery of a large timescale candidate microlensing event of a bulge stellar source based on near-infrared observations with the VISTA Variables in the Via Lactea Survey (VVV). The new microlensing event is projected only 3.5 arcmin away from the center of the globular cluster NGC 6553. The source appears to be a bulge giant star with magnitude K_s_=13.52, based on the position in the color-magnitude diagram. The foreground lens may be located in the globular cluster, which has well-known parameters such as distance and proper motions. If the lens is a cluster member, we can directly estimate its mass simply following Paczynski which is a modified version of the more general case due to Refsdal. In that case, the lens would be a massive stellar remnant, with M=1.5-3.5M_{sun}_. If the blending fraction of the microlensing event appears to be small, and this lens would represent a good isolated black hole (BH) candidate, that would be the oldest BH known. Alternative explanations (with a larger blending fraction) also point to a massive stellar remnant if the lens is located in the Galactic disk and does not belong to the globular cluster.
