The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III

TL;DR

This paper documents the final public data releases DR11 and DR12 of SDSS-III, detailing the survey components (BOSS, APOGEE, MARVELS) and the data products, reductions, and access mechanisms. DR12 consolidates SDSS-III data, adding millions of spectra across BOSS, APOGEE, MARVELS, and SEGUE-2, and delivering significant APOGEE abundance improvements and RC catalogs, while reporting on MARVELS calibration challenges and ongoing pipeline advancements. It also describes the data-distribution infrastructure, pipeline versioning, ancillary programs, and the transition to SDSS-IV, outlining the continued pursuit of cosmology and Galactic archaeology with the next generation surveys. Overall, the release embodies a comprehensive, multi-survey legacy dataset enabling broad cosmological and stellar-population science for the astronomical community.

Abstract

The third generation of the Sloan Digital Sky Survey (SDSS-III) took data from 2008 to 2014 using the original SDSS wide-field imager, the original and an upgraded multi-object fiber-fed optical spectrograph, a new near-infrared high-resolution spectrograph, and a novel optical interferometer. All the data from SDSS-III are now made public. In particular, this paper describes Data Release 11 (DR11) including all data acquired through 2013 July, and Data Release 12 (DR12) adding data acquired through 2014 July (including all data included in previous data releases), marking the end of SDSS-III observing. Relative to our previous public release (DR10), DR12 adds one million new spectra of galaxies and quasars from the Baryon Oscillation Spectroscopic Survey (BOSS) over an additional 3000 sq. deg of sky, more than triples the number of H-band spectra of stars as part of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE), and includes repeated accurate radial velocity measurements of 5500 stars from the Multi-Object APO Radial Velocity Exoplanet Large-area Survey (MARVELS). The APOGEE outputs now include measured abundances of 15 different elements for each star. In total, SDSS-III added 2350 sq. deg of ugriz imaging; 155,520 spectra of 138,099 stars as part of the Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2) survey; 2,497,484 BOSS spectra of 1,372,737 galaxies, 294,512 quasars, and 247,216 stars over 9376 sq. deg; 618,080 APOGEE spectra of 156,593 stars; and 197,040 MARVELS spectra of 5,513 stars. Since its first light in 1998, SDSS has imaged over 1/3 of the Celestial sphere in five bands and obtained over five million astronomical spectra.

Figures (11)

• Figure 1: Distribution of the number of observations made of each MARVELS star that was processed by the CCF+DFDI (black solid) and the UF1D (red dashed) pipelines and met the respective quality cuts.
• Figure 2: MARVELS sky coverage in equatorial coordinates. Each plate is plotted with a color-coding giving the number of epochs the plate was observed.
• Figure 3: (left) Conceptual illustration of a portion of the spectrum of one star from MARVELS dispersed fixed-delay interferometry. For simplicity, we show only five absorption lines in this sample wavelength region; the full MARVELS wavelength range features thousands of absorption lines -- most of these are blended at the MARVELS dispersion of $R\sim11,000$. The diagonal pattern of constructive and destructive interference is not sharp as in this simple diagram, but rather varies sinusoidally with $y$. The phase of the best-fitting sinusoid to each column of the data determines the corresponding wavelength shift, given the slope of the interference comb. (right) Illustration of some of the real-world effects of variable projection of spectra onto the focal plane, spectrograph alignment, point spread function, and the variable slope of the interference comb. Note the additional blending in each set of closely-separated absorption lines. There are 120 of these spectra (each roughly 4096 pixels by 34 pixels) per MARVELS exposure.
• Figure 4: Distribution of RMS of radial velocity measurements of MARVELS stars (grey points) for the DFDI (left), and UF1D (right) analyses, as a function of apparent magnitude. The mode of the RMS in each 0.5 mag bin (blue circles and line) highlights the significant number of stars with RMS near 50--100 m s$^{-1}$. However, a comparison with the theoretical photon limit (red dashed line) illustrates that the bulk of the RMS values are many times higher than the limit. Despite this, there are stars whose radial velocity repeatability approaches the theoretical limit, suggesting that the large scatter for many of the observations is due to calibration problems, which might be improved with further development of the pipeline.
• Figure 5: MARVELS observations of the radial velocities of the stars (left) HD68988 compared to the exoplanet model of Butler06; and (right) HIP-14810 compared to the model of Wright09. The phased data are shown over two periods for ease of visualization.