What’s New in DR12
Data Release 12 (DR12) is the final release of the Sloan Digital Sky Survey III. DR12 contains all data taken by all phases of the SDSS through 14 July 2014. This page describes new features of DR12, and what has changed since DR10.
Data Release 11 was an internal bookkeeping release. For information about DR11, see the published DR12 paper. DR12 includes all information in DR11 and previous releases of SDSS.
Complete extragalactic spectra
BOSS has successfully completed its mission to measure the baryon acoustic oscillation (BAO) feature in the clustering of galaxies and in the Lyman-α forest. Spectroscopic coverage is now complete in two large contiguous regions in the Northern and Southern Galactic Caps.
DR12 BOSS spectra represent a ~40% increase over the previous data release (DR10). DR12 features improved spectrophotometric flux calibration, and also adds twenty-three new ancillary science targeting programs supporting a wide variety of investigations.
BOSS spectra are available through both the SAS and the CAS. For more information on the new DR12 BOSS data, see:
Star spectra with elemental abundances
APOGEE is a large-scale survey of Milky Way chemistry and kinematics. High-resolution infrared (H-band) spectroscopy allows APOGEE to bypass interstellar dust extinction to provide a large, uniform database of precision stellar measurements throughout the galaxy, from the central bulge to the halo.
DR12 contains three times as many APOGEE spectra as DR10 did. APOGEE has also added four new ancillary science programs and extended two existing programs. DR12 improves all APOGEE spectra by providing not only best-fitting values of global stellar parameters, but also individual elemental abundances for Al, Ca, C, Fe, K, Mg, Mn, Na, Ni, N, O, Si, S, Ti, and V.
APOGEE infrared spectra are available through both the SAS and the CAS. For more information on the new DR12 APOGEE data, see:
Stellar radial velocities from interferometry
DR12 newly includes all data from MARVELS, a large-scale survey that monitored more than 5,000 stars for radial velocity changes, with the goal of finding exoplanets and small brown dwarfs. MARVELS data in DR12 include 20-40 observations each of bright (V < 12) FGK and giant stars, taken between October 2008 and July 2012.
DR12 includes all MARVELS raw data products, our current best 2-D and 1-D pipeline analyses, stellar parameters for targeted stars, and radial velocity measurements. We encountered significant challenges in calibrating the RV stability of the MARVELS instrument, resulting in significant RMS scatter of radial velocity measurements. However, the distribution of RMS values extends to near photon noise limits, so we are cautiously optimistic that further improvements in data processing and calibration will yield improved sensitivity to giant planets.
MARVELS observations and data are available through both the SAS and the CAS. For more information on MARVELS, see: