5 research outputs found
SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
Building on the legacy of the Sloan Digital Sky Survey (SDSS-I and II),
SDSS-III is a program of four spectroscopic surveys on three scientific themes:
dark energy and cosmological parameters, the history and structure of the Milky
Way, and the population of giant planets around other stars. In keeping with
SDSS tradition, SDSS-III will provide regular public releases of all its data,
beginning with SDSS DR8 (which occurred in Jan 2011). This paper presents an
overview of the four SDSS-III surveys. BOSS will measure redshifts of 1.5
million massive galaxies and Lya forest spectra of 150,000 quasars, using the
BAO feature of large scale structure to obtain percent-level determinations of
the distance scale and Hubble expansion rate at z<0.7 and at z~2.5. SEGUE-2,
which is now completed, measured medium-resolution (R=1800) optical spectra of
118,000 stars in a variety of target categories, probing chemical evolution,
stellar kinematics and substructure, and the mass profile of the dark matter
halo from the solar neighborhood to distances of 100 kpc. APOGEE will obtain
high-resolution (R~30,000), high signal-to-noise (S/N>100 per resolution
element), H-band (1.51-1.70 micron) spectra of 10^5 evolved, late-type stars,
measuring separate abundances for ~15 elements per star and creating the first
high-precision spectroscopic survey of all Galactic stellar populations (bulge,
bar, disks, halo) with a uniform set of stellar tracers and spectral
diagnostics. MARVELS will monitor radial velocities of more than 8000 FGK stars
with the sensitivity and cadence (10-40 m/s, ~24 visits per star) needed to
detect giant planets with periods up to two years, providing an unprecedented
data set for understanding the formation and dynamical evolution of giant
planet systems. (Abridged)Comment: Revised to version published in The Astronomical Journa
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Not AvailableThe present work was carried out to study the ability of avian "Extract Egg" (EE) for reprogramming caprine fetal cells. The isolated caprine fetal cells were cultured in stem cell media supplemented with different percentages of either EE or FBS. The results indicated that the supplementation of 2-4% EE formed lesser but larger size stem cell like cell colonies as compared to 6% or 10% EE. The expression of pluripotent genes were comparatively higher in colonies developed in 2% or 4% as compared to 6% or 10% EE. Further, immunocytochemistry revealed that the colonies developed in all percentage of EE expressed pluripotent markers like Oct4, Nanog, TRA-1-60 and TRA-1-81. Our findings indicated that avian EE has the potentiality to reprogram caprine fetal cells into embryonic state which may help in generation of pluripotent stem cells without using viral vector.Not Availabl
The Radial Velocity Experiment (RAVE):Second data release
We present the second data release of the Radial Velocity Experiment (RAVE),
an ambitious spectroscopic survey to measure radial velocities (RVs) and
stellar atmosphere parameters of up to one million stars using the 6dF
multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the
Anglo-Australian Observatory (AAO). It is obtaining medium resolution spectra
(median R=7,500) in the Ca-triplet region (8,410--8,795 \AA) for southern
hemisphere stars in the magnitude range 9<I<12. Following the first data
release (Steinmetz et al. 2006) the current release doubles the sample of
published RVs, now containing 51,829 RVs for 49,327 individual stars observed
on 141 nights between April 11 2003 and March 31 2005. Comparison with external
data sets shows that the new data collected since April 3 2004 show a standard
deviation of 1.3 km/s, about twice better than for the first data release. For
the first time this data release contains values of stellar parameters from
22,407 spectra of 21,121 individual stars. They were derived by a penalized
\chi^2 method using an extensive grid of synthetic spectra calculated from the
latest version of Kurucz models. From comparison with external data sets, our
conservative estimates of errors of the stellar parameters (for a spectrum with
S/N=40) are 400 K in temperature, 0.5 dex in gravity, and 0.2 dex in
metallicity. We note however that the internal errors estimated from repeat
RAVE observations of 822 stars are at least a factor 2 smaller. We demonstrate
that the results show no systematic offsets if compared to values derived from
photometry or complementary spectroscopic analyses. The data release includes
proper motion and photometric measurements. It can be accessed via the RAVE
webpage: http://www.rave-survey.org and through CDS.