Search

Start Over Validation Level 2
24301. Wide-orbit companions to K-type stars in Sco-Cen
ID:
ivo://CDS.VizieR/J/A+A/657/A53
Title:
Wide-orbit companions to K-type stars in Sco-Cen
Short Name:
J/A+A/657/A53
Date:
17 Mar 2022 14:41:58
Publisher:
CDS
Description:
The detection of low-mass companions to stellar hosts is important for testing the formation scenarios of these systems. Companions at wide separations are particularly intriguing objects as they are easily accessible for variability studies of the rotational dynamics and cloud coverage of these brown dwarfs or planetary-mass objects. We aim to identify new low-mass companions to young stars using the astrometric measurements provided by the Gaia space mission. When possible, we use high-contrast imaging data collected with VLT/SPHERE. We identified companion candidates from a sample of K-type, pre-main-sequence stars in the Scorpius Centaurus association using the early version of the third data release of the Gaia space mission. Based on the provided positions, proper motions, and magnitudes, we identified all objects within a predefined radius, whose differential proper motions are consistent with a gravitationally bound system. As the ages of our systems are known, we derived companion masses through comparison with evolutionary tracks. For seven identified companion candidates we used additional data collected with VLT/SPHERE and VLT/NACO to assess the accuracy of the properties of the companions based on Gaia photometry alone. We identify 110 comoving companions that have a companionship likelihood of more than 95%. Further color-magnitude analysis confirms their Sco-Cen membership. We identify ten especially intriguing companions that have masses in the brown dwarf regime down to 20M_{Jup}_. Our high-contrast imaging data confirm both astrometry and photometric masses derived from Gaia alone. We discovered a new brown dwarf companion, TYC 8252-533-1 B, with a projected separation of approximately 570au from its Sun-like primary. It is likely to be located outside the debris disk around its primary star and SED modeling of Gaia, SPHERE, and NACO photometry provides a companion mass of 52^+17^_-11_M_{Jup}_. We show that the Gaia database can identify low-mass companions at wide separations from their host stars. For K-type Sco-Cen members, Gaia can detect sub-stellar objects at projected separations larger than 300au and with a sensitivity limit beyond 1000 and a lower mass limit down to 20M_{Jup}_. A similar analysis of other star-forming regions could significantly enlarge the sample size of such objects and facilitate testing of the formation and evolution theories of planetary systems.
24302. Wide-orbit Exoplanet search with IR Direct imaging
ID:
ivo://CDS.VizieR/J/AJ/156/137
Title:
Wide-orbit Exoplanet search with IR Direct imaging
Short Name:
J/AJ/156/137
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report results from the Wide-orbit Exoplanet search with InfraRed Direct imaging, or WEIRD, a survey designed to search for Jupiter-like companions on very wide orbits (1000-5000 au) around young stars (<120 Myr) that are known members of moving groups in the solar neighborhood (<70 pc). Companions that share the same age, distance, and metallicity as their host while being on large enough orbits to be studied as "isolated" objects make prime targets for spectroscopic observations, and they are valuable benchmark objects for exoplanet atmosphere models. The search strategy is based on deep imaging in multiple bands across the near-infrared domain. For all 177 objects of our sample, z'_ab_, J, [3.6], and [4.5] images were obtained with CFHT/MegaCam, GEMINI/GMOS, CFHT/WIRCam, GEMINI/Flamingos-2, and Spitzer/IRAC. Using this set of four images per target, we searched for sources with red z'_ab_ and [3.6]-[4.5] colors, typically reaching good completeness down to 2 M_Jup_ companions, while going down to 1 M_Jup_ for some targets, at separations of 1000-5000 au. The search yielded four candidate companions with the expected colors, but they were all rejected through follow-up proper motion observations. Our results constrain the occurrence of 1-13 M_Jup_ planetary-mass companions on orbits with a semimajor axis between 1000 and 5000 au at less than 0.03, with a 95% confidence level.
24303. Wide southern double stars
ID:
ivo://CDS.VizieR/J/other/PASA/24.118
Title:
Wide southern double stars
Short Name:
J/other/PASA/24.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Astrometric CCD observations have been made of wide (~3 to 60 arcsec) southern double stars selected from the Washington Double Star catalogue (WDS). Southern double stars have not been well studied in the past; typically they had not been measured since about 1930, and ~50% of them have been observed only once before our observations. Of the pairs measured ~80% show no evidence of motion since the last observation. This is Paper II in which we present the observations of 290 WDS stars in the approximate RA range 17h13m to 07h30m and in the declination range -70{deg} to -60{deg}. We suggest 412 companions for these 290 stars and list 29 (10%) pairs that have shown significant motion.
24304. WiggleZ dark energy survey (DR1)
ID:
ivo://CDS.VizieR/J/MNRAS/401/1429
Title:
WiggleZ dark energy survey (DR1)
Short Name:
J/MNRAS/401/1429
Date:
21 Oct 2021
Publisher:
CDS
Description:
The WiggleZ Dark Energy Survey is a survey of 240000 emission-line galaxies in the distant Universe, measured with the AAOmega spectrograph on the 3.9-m Anglo-Australian Telescope (AAT). The primary aim of the survey is to precisely measure the scale of baryon acoustic oscillations (BAO) imprinted on the spatial distribution of these galaxies at look-back times of 4-8Gyr. The target galaxies are selected using ultraviolet (UV) photometry from the Galaxy Evolution Explorer satellite, with a flux limit of NUV<22.8mag. We also require that the targets are detected at optical wavelengths, specifically in the range 20.0<r<22.5mag. We use the Lyman break method applied to the UV colours, with additional optical colour limits, to select high-redshift galaxies. The galaxies generally have strong emission lines, permitting reliable redshift measurements in relatively short exposure times on the AAT. The median redshift of the galaxies is z_med_=0.6. The redshift range containing 90 per cent of the galaxies is 0.2<z<1.0. The survey will sample a volume of ~1Gpc^3^ over a projected area on the sky of 1000deg^2^, with an average target density of 350deg^-2^.
24305. WiggleZ Dark Energy Survey final DR
ID:
ivo://CDS.VizieR/J/MNRAS/474/4151
Title:
WiggleZ Dark Energy Survey final DR
Short Name:
J/MNRAS/474/4151
Date:
02 Mar 2022 00:09:00
Publisher:
CDS
Description:
The WiggleZ Dark Energy Survey measured the redshifts of over 200000 ultraviolet (UV)-selected (N_UV_<22.8mag) galaxies on the Anglo-Australian Telescope. The survey detected the baryon acoustic oscillation signal in the large-scale distribution of galaxies over the redshift range 0.2<z<1.0, confirming the acceleration of the expansion of the Universe and measuring the rate of structure growth within it. Here, we present the final data release of the survey: a catalogue of 225415 galaxies and individual files of the galaxy spectra. We analyse the emission-line properties of these UV-luminous Lyman-break galaxies by stacking the spectra in bins of luminosity, redshift, and stellar mass. The most luminous (-25mag<M_FUV_< -22mag) galaxies have very broad H{beta} emission from active nuclei, as well as a broad second component to the [OIII] (495.9nm, 500.7nm) doublet lines that is blueshifted by 100km/s, indicating the presence of gas outflows in these galaxies. The composite spectra allow us to detect and measure the temperature-sensitive [OIII] (436.3nm) line and obtain metallicities using the direct method. The metallicities of intermediate stellar mass (8.8<log(M*/M_{sun}_)<10) WiggleZ galaxies are consistent with normal emission-line galaxies at the same masses. In contrast, the metallicities of high stellar mass (10<log(M*/M_{sun}_)<12) WiggleZ galaxies are significantly lower than for normal emission-line galaxies at the same masses. This is not an effect of evolution as the metallicities do not vary with redshift; it is most likely a property specific to the extremely UV-luminous WiggleZ galaxies.
24306. WiggleZ Final Data Release ConeSearch
ID:
ivo://nci.org.au/wigglez/conesearch
Title:
WiggleZ Final Data Release ConeSearch
Short Name:
WiggleZ Final CS
Date:
14 Mar 2019 08:11:28
Publisher:
National Computational Infrastructure
Description:
WiggleZ final data release
24307. WiggleZ Final Data Release TAP
ID:
ivo://nci.org.au/wigglez/tap
Title:
WiggleZ Final Data Release TAP
Short Name:
WiggleZ TAP
Date:
06 Sep 2024 07:01:17
Publisher:
National Computational Infrastructure
Description:
WiggleZ final data release TAP service
24308. WiggleZ Image Download Service
ID:
ivo://anusf.anu.au/wigglez/image/DownLoad
Title:
WiggleZ Image Download Service
Short Name:
WiggleZ getImage
Date:
18 Jun 2019 20:18:26
Publisher:
ivo://anusf.anu.au
Description:
The WiggleZ Project Image Download Service
24309. Wilson-Bappu relation in late-type stars
ID:
ivo://CDS.VizieR/J/A+A/401/997
Title:
Wilson-Bappu relation in late-type stars
Short Name:
J/A+A/401/997
Date:
21 Oct 2021
Publisher:
CDS
Description:
Wilson & Bappu (1957ApJ...125..661W) have shown the existence of a remarkable correlation between the width of the emission in the core of the K line of CaII and the absolute visual magnitude of late-type stars. Here we present a new calibration of the Wilson-Bappu effect based on a sample of 119 nearby stars. We use, for the first time, width measurements based on high resolution and high signal to noise ratio CCD spectra and absolute visual magnitudes from the Hipparcos database.
24310. Wind-driving protostellar accretion discs
ID:
ivo://CDS.VizieR/J/MNRAS/412/1162
Title:
Wind-driving protostellar accretion discs
Short Name:
J/MNRAS/412/1162
Date:
21 Oct 2021
Publisher:
CDS
Description:
We continue our study of weakly ionized protostellar accretion discs that are threaded by a large-scale magnetic field and power a centrifugally driven wind. It has been argued that there is already evidence in several protostellar systems that such a wind transports a significant fraction of the angular momentum from at least some part of the disc. We model this situation by considering a radially localized disc model in which the matter is everywhere well coupled to the field and the wind is the main repository of excess angular momentum. We consider stationary configurations in which magnetic diffusivity counters the shearing and advection of the magnetic field lines. In Wardle & Koenigl (1997, ASP Conf. Ser., 121, 561) we analysed the disc structure in the hydrostatic approximation (vertical motions neglected inside the disc) and presented exact disc/wind solutions for the ambipolar diffusivity regime. In Koenigl, Salmeron & Wardle (Paper I, 2010MNRAS.401..479K) we generalized the hydrostatic analysis to the Hall and Ohm diffusivity domains and used it to identify the disc parameter sub-regimes in which viable solutions with distinct physical properties can be expected to occur. In this paper we test the results of Paper I by deriving full numerical solutions (integrated through the sonic critical surface) of the disc equations in the Hall domain.

Limit your search

more »

more »

more »

more »

more »

more »

more »

more »