The eleventh and twelfth data releases of the Sloan Digital Sky Survey: final data from SDSS-III

TL;DR: 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 spectrogram, and a novel optical interferometer.

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.

Summary

1. INTRODUCTION

• Comprehensive wide-field imaging and spectroscopic surveys of the sky have played a key role in astronomy, leading to fundamental new breakthroughs in their understanding of the Solar System; their Milky Way Galaxy and its constituent stars and gas; the nature, properties, and evolution of galaxies; and the universe as a whole.
• The Sloan Exploration of Galactic Understanding and Evolution 2 (SEGUE-2; C. Rockosi et al. 2015, in preparation) used the SDSS-I/II spectrographs to obtain R 2000∼ spectra of stars at high and low Galactic latitudes to study Galactic structure, dynamics, and stellar populations.
• The SDSS-III completed data-taking in 2014 July, and the present paper describes both DR11 and Data Release 12 (DR12).

2. SUMMARY OF COVERAGE

• DR12 presents all of the data gathered by SDSS-III, which extended from 2008 August to 2014 June, plus a small amount of data gathered using the BOSS and APOGEE instruments in the first two weeks of 2014 July under the auspices of the next phase of the SDSS, SDSS-IV (see Section 7).
• The MARVELS data (Section 3) include ∼5500 unique stars, most of which have 20–40 observations (and thus RV measurements) per star.
• In addition, prototype and commissioning data were obtained during SDSS-III for the SDSS-IV Mapping Nearby Galaxies at APO project (Bundy et al. 2015), which uses the BOSS spectrographs to measure spatially resolved spectra across galaxies.
• The raw data from these observations are included in DR12, but reduced data products (including kinematic and stellar population measurements) will be released only with the first SDSS-IV data release.
• The authors also made a single fiber connection from the APOGEE instrument to the nearby New Mexico State University (NMSU) 1 m telescope at APO for observations when the APOGEE instrument was not being fed photons from the 2.5 m telescope.

3. MARVELS

• This survey aimed to determine the distribution of gas giant planets (M 0.5> MJupiter) in orbits of periods 2< years and to explore the “brown dwarf desert” over the mass range M M13 80 Jupiter< < (Grether & Lineweaver 2006).
• MARVELS RVs are differential measurements based on the shift of a star’s fringing spectrum at the current epoch relative to one from the template epoch.
• The statistics in the following indented lines include only those observations which met the requirements of being survey quality.

3.1. Scope and Status

• MARVELS data collection began in 2008 October and ended in 2012 July.
• The problems in RV calibration, the shortened MARVELS observing period, and the fact that the second MARVELS spectrograph was never built meant that this ideal was not met for all targets.
• For any particular star, the time baseline between the first and last observation was thus typically 1.5–2 years.
• During its four years of operation, MARVELS obtained 1565 observations of 95 fields collecting multi-epoch data for 5700 stars, with observations of 60 stars per target field.

3.2. A Brief Guide to MARVELS Data

• Both sets of fibers were plugged at the same time.
• In between observations of the two fields, the “gang” connector that joins the fibers from the cartridges to the long fibers that run to the MARVELS instruments was switched between the two sets of fibers.
• A MARVELS exposure is the result of light from each of 60 fibers passing through a two-beam interferometer with one slanted mirror and then being dispersed in wavelength before being recorded on a 4k 4k× CCD.
• The RVs for each star can then be calculated from a comparison of the fringing spectrum observations at different epochs.
• The authors provide the 2D raw images, the 2D slices of extracted spectra, the 1D collapsed spectra, and the calculated stellar velocities and associated observational metadata for each spectrum of each star and field.

3.3. Target Selection

• The authors here summarize the key aspects of the MARVELS target selection in each two-year phase of the survey.
• Instead, the SDSS pipeline was used with some custom modifications to provide stellar spectra suitable for processing with the SEGUE Spectroscopic Processing Pipeline (SSPP; Lee et al. 2008).
• From 2011 January onward all MARVELS observations were carried out simultaneously with APOGEE, using plug plates drilled with holes for both sets of targets.
• This joint observation mode yielded significant overall observational efficiencies, but imposed the restriction that both surveys observe the same fields with the same cadence.

3.4. MARVELS Data Analysis

• It splits each input stellar spectrum into two beams, and then projects a slanted interference pattern of the recombined beams through a spectrograph .
• The dispersed slanted interference pattern effectively magnifies the resolution of a moderate-resolution spectrograph (R 11,000∼ ) by translating wavelength shifts in the dispersion (“x”) direction to much larger shifts in the “y” position.
• This slope is ∼5 pixel pixel−1 for MARVELS.
• The key challenges in the processing of MARVELS data are the calibration of the wavelength solution on the detector, identification and extraction of each spectrum, and the measurement of the slant of the interferometric comb and of the resulting interference pattern of the absorption-line features.
• The authors here outline the important differences in the CCF+DFDI and UF1D processing.

3.4.1. Extraction of Spectra from the 2D Images

• A key part of spectroscopic processing is determining the “trace,” i.e., where the light from a given fiber target falls on the CCD.
• In an idealized instrument, the trace would lie horizontally along the CCD (constant y), and the light at a given wavelength would be distributed perpendicular to the trace (constant x), In practice, this is not true, and the authors correct for these two according through a “trace correction” and “deslant correction.”.
• The CCF+DFDI pipeline uses available Tungsten lamp continuum exposures with a diffuser to determine the trace of the spectrum on the CCD, and Thorium-Argon arc spectra to determine the deslant correction.
• The UF1D pipeline uses the Tungsten lamp exposures taken through an iodine cell to determine the trace, and the absorption lines in the observed stellar spectra to determine the deslant correction.
• The pipelines extract and correct 2D arrays for each spectrum based on their respective trace and deslant corrections.

3.4.2. Compression to 1D Spectra

• The CCF+DFDI pipeline takes the 2D rectified spectrum and fits a sinusoid to the interference pattern along the y (slit) direction.
• The spectrum is then collapsed along y, and the resulting 1D spectrum plus sinusoidal fit parameters are stored.
• The combination of the collapsed spectrum and the sinusoidal fits is denoted a “whirl” in the provided CCF+DFDI data products.
• The UF1D pipeline focuses on improvements to the instrumental calibration without adding complications from the details of the phase extraction.
• It simply collapses the 2D rectified spectra along the y direction to create 1D spectra, removing the information contained in the fringes.

3.4.3. Characterizing the Instrumental Wavelength Drift

• Determining the instrumental wavelength drift over time is critical in deriving reliable RV measurements.
• The instrumental drift is measured from calibration lamp exposures taken before and after each science frame.
• The calibration exposures are from a Tungsten lamp shining through a temperature-stabilized Iodine gas cell (TIO).
• For the CCF+DFDI pipeline, the shift for each star was determined by comparing the extracted TIO spectrum to a single reference lamp spectrum taken on MJD 55165 (2009 November 29), and the measured RV for the star in question was corrected by the resulting offset.
• The large variance in the resulting RVs has shown that this approach does not fully capture the complex nature of the calibration changes across the detector.

3.4.4. Measuring the Stellar RV Shifts

• In CCF+DFDI, the stellar RV is measured by comparing the extracted stellar spectrum from a given stellar exposure to the spectrum at the template epoch.
• This raw stellar RV shift is corrected for the instrumental drift determination from the previous step and labeled as the CCF measurement.
• These two successive calculations are reported in separate tables in DR11 with CCF and DFDI suffixes in the name of the respective tables.
• Because of the two-beam nature of the DFDI instrument, each star observation results in two spectra.
• To estimate the RV for the star on a given epoch one would in principle simply average the RVs from the two measurements.

3.5. Current Status and Remaining Challenges

• As Figure 4 shows, the current data processing results in stellar RV variations of 50 m s−1 or larger even at high S/N, a value several times greater than that expected from photon statistics.
• Work continues on improving the analysis of the MARVELS data and their understanding of the long-term systematic effects.
• Figure 5 shows MARVELS RV measurements of two stars with known exoplanets, showing that MARVELS data are in good agreement with existing orbital models for these systems.
• The upper band of objects with rms from 1–10 km s−1 is predominantly true astrophysical variation from binary star systems.
• The distribution of objects with rms values in the range of 100 m s−1 is bounded near the photon limit, but the bulk lies several times above these limits.

4.1. Scope and Summary

• The BOSS main survey of galaxies and quasars over two large contiguous regions of sky in the northern and southern Galactic Caps was completed in Spring 2014.
• The majority of the galaxies were uniformly targeted for large-scale structure studies in a sample focused on relatively low redshifts (“LOWZ,” with z 0.4< ) and a sample with z0.4 0.7< < designed to give a sample approximately volume-limited in stellar mass (“CMASS”; B. Reid et al. 2015, in preparation).
• The total footprint is about 10,400 deg2 ; the value of 9376 deg2 in Table 1 excludes masked regions due to bright stars and data that do not meet their survey requirements.
• The main BOSS survey was completed in 2014 February.
• The additional dark time available through the 2014 summer shutdown was devoted to a portfolio of additional science programs designed to maximize the science return while taking advantage of the unique abilities of the SDSS system.

4.2. Highlights from BOSS DR11

• The DR11 and DR12 releases of BOSS data constitute increments of 35% and 47% in the number of spectra over DR10, respectively, processed using very similar pipelines.
• These increases were significant enough to warrant a new set of BOSS cosmological analyses for each of these releases.
• These key papers were one of the motivations for tagging a DR11 data set for later public release along with DR12.
• The cosmology analyses based on DR11 data include studies of isotropic galaxy clustering (Guo et al. 2015), anisotropic galaxy clustering (Samushia et al.
• The BOSS team plans a similar set of papers based on the full DR12 analyses.

4.3. Data Reduction Changes for DR12

• The pipeline software for reduction of BOSS spectroscopic data was largely unchanged between DR10 and DR11.
• There were, however, some significant improvements to the spectrophotometric flux-calibration routine for DR12.
• These improvements were made to mitigate low-level imprinting of.
• It has a small but non-negligible effect on the analysis of the Lyα forest across many thousands of quasar spectra.
• One (v5_6_5) is the “DR11” version that defines a homogeneous sample of BOSS data taken through Summer 2013; this is the version used in the cosmological analyses described in Section 4.2 above.

5. APOGEE

• The authors release both DR11 and DR12 versions of the APOGEE outputs, with considerably more stars (see Table 1) in the latter.
• The DR11 parameters and abundances use the same version of the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP; A. E. García Pérez et al. 2015, in preparation) as in DR10.
• The DR12 version of ASPCAP is a major upgrade, in which abundances are determined for 15 individual elements.
• These improvements do not change the derived fundamental stellar parameters systematically, but do improve their accuracy.

5.1. Scope and Summary

• It also uses the updated analysis pipeline described above.
• The APOGEE spectroscopic data processing is described in Nidever et al. (2015).
• Figure 10 shows the observed distribution of the key stellar parameters and abundances for APOGEE DR12.

5.2. Abundances of 15 Elements in APOGEE DR12

• The spectra are fit to models based on spectral libraries from astronomical observations combined with laboratory and theoretical transition probabilities and damping constants for individual species.
• The final measurements and associated uncertainties are calibrated to observations of stellar clusters, whose abundance patterns are assumed to be uniform.
• The abundances are most reliable for stars with effective surface temperatures in the range 3800 K Teff⩽ ⩽ 5250 K.
• For cooler atmospheres (T 3800eff < K), the strengths of molecular transitions are increasingly sensitive to temperature, surface gravity, molecular equilibrium, and other physical details, giving rise to a greater uncertainty in the inferred abundances.

5.3. Red Clump Stars in APOGEE

• This APOGEE data release also contains the DR11 and DR12 versions of the APOGEE red-clump (APOGEE-RC) catalog.
• Red clump stars, helium core-burning stars in metalrich populations, are good standard candles, and thus can be used as a spatial tracer of the structure of the disk and the bulge.
• The calibration starting from the uncalibrated outputs of ASPCAP for surface gravity, glog uncal.

5.4. Additional Target Classes in APOGEE DR12

• Target selection for APOGEE was described in Zasowski et al. (2013).
• DR12 adds four additional ancillary target classes to those described in Zasowski et al. (2013) and extends two previous ancillary programs.
• This ancillary project observed 159 Kepler Objects of Interest (KOI; e.g., Burke et al. 2014), 23 M dwarfs, and 25 eclipsing binaries, at high cadence (∼21 observations), over a period of 8 months to study binarity, abundances, and false positives in the planet host sample.
• Re-Observation of Commissioning Bulge Stars to Verify Radial Velocity Accuracy.
• These observations are labeled with the setting of APOGEE_TARGET2 bit 21.

6. DATA DISTRIBUTION

• The data for DR11 and DR12 are distributed through the same mechanisms available in DR10, with some URL modifications to accommodate the ongoing transition to SDSS-IV and an associated unification of the SDSS web presence under the “sdss.org” domain.
• Raw and processed image and spectroscopic data are available through the Science Archive Server144(Neilsen 2008) and through an interactive web application.
• APOGEE, BOSS, and SEGUE are publicly available at http:// www.sdss.org/dr12/software/products.

Figures

Table 1 (Continued)

Figure 6. BOSS DR11 (left) and DR12 (right) spectroscopic sky coverage in the northern Galactic Cap (top) and southern Galactic Cap (bottom). The gray region (visible most clearly in the DR11 map) was the coverage goal for the final survey. The DR12 coverage map shows that we exceeded our original goals with a final total of 10,400 deg2. The color coding indicates the fraction of CMASS galaxy targets that receive a fiber. The average completeness is 94% due to the limitation that no two fibers can be placed closer than 62″ on a given plate.

Figure 11. Near-infrared colors and H magnitudes of APOGEE targets as observed (left panels) and corrected for Galactic dust extinction (right panels). The vertical dashed line in the lower-right panel at J K( ) 0.5s 0− = mag indicates the selection cutoff for the main APOGEE red giant sample. Objects bluer than this line are from observations of telluric calibration stars, commissioning data, or ancillary program targets. The gray scale is logarithmic in number of stars.

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 4. Distribution of rms of radial velocity measurements of MARVELS stars (gray 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 Butler et al. (2006), and (right) HIP-14810 compared to the model of Wright et al. (2009). The phased data are shown over two periods for ease of visualization.

Figure 10. Key stellar parameters (Teff , glog ) and key metallicity indicators ([M/H], [C/M], [N/M], [α/M]) for stars with APOGEE observations in DR12. These distributions are strongly affected by the selection of stars targeted for APOGEE spectroscopy. The gray scale is logarithmic in number of stars.

Table 6 BOSS Ancillary Programs with Dedicated Plates

Figure 8. Distribution of S/N of APOGEE stars in DR12. With 1.5 pixels per effective half-resolution element, the science requirements goal of S/N 100⩾ /halfresolution element is achieved with S/N 82⩾ pixel−1 (dashed green line). (Left) 2D histogram of S/N vs. 2MASS H magnitude. The red dashed–dotted lines denote the magnitude limits for the different bins of target brightness. The number of planned visits to APOGEE main targets was (1, 3, 6, 12, 24) visits for H (11.0, 12.2, 12.8, 13.3, 13.8)< mag. (Right) 1D histogram of S/N. The systematic floor in the effective S/N is ∼200 (red dashed–dotted line).

Figure 7. Sky coverage of APOGEE DR12 observations in Galactic coordinates. The number of visits to each field is denoted by the color coding from 1 visit (blue) through 12 or more visits (magenta).

Figure 9. (Left) distribution of time intervals between observations of a given APOGEE target in DR12. (Right) distribution of number of visits for individual APOGEE targets in DR12.

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 ∼ 11,000. 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.

Table 7 SEQUELS Targets

Table 5 Parallel BOSS Ancillary Programs

Table 4 Spectroscopic Pipeline Versions Associated With Each BOSS Data Release

Table 2 Wavelength Ranges Masked During BOSS Spectrophotometric Calibration

Table 3 Significant Changes to the BOSS Spectrographs and the Data Reduction Pipeline

Full text

THE ELEVENTH AND TWELFTH DATA RELEASES OF THE SLOAN DIGITAL SKY SURVEY:
FINAL DATA FROM SDSS-III
Shadab Alam
1
, Franco D. Albareti
2
, Carlos Allende Prieto
3,4
, F. Anders
5
, Scott F. Anderson
6
, Timothy Anderton
7
,
Brett H. Andrews
8,9
, Eric Armengaud
10
, Éric Aubourg
11
, Stephen Bailey
12
, Sarbani Basu
13
, Julian E. Bautista
11
,
Rachael L. Beaton
14,15
, Timothy C. Beers
16
, Chad F. Bender
17,18
, Andreas A. Berlind
19
, Florian Beutler
12
,
Vaishali Bhardwaj
6,12
, Jonathan C. Bird
19
, Dmitry Bizyaev
20,21,22
, Cullen H. Blake
23
, Michael R. Blanton
24
,
Michael Blomqvist
25
, John J. Bochanski
6,26
, Adam S. Bolton
7
, Jo Bovy
27,136
, A. Shelden Bradley
20
,
W. N. Brandt
17,28,29
, D. E. Brauer
5
, J. Brinkmann
20
, Peter J. Brown
30
, Joel R. Brownstein
7
, Angela Burden
31
,
Etienne Burtin
10
, Nicolás G. Busca
11,32,33
, Zheng Cai
34
, Diego Capozzi
31
, Aurelio Carnero Rosell
32,33
,
Michael A. Carr
35
, Ricardo Carrera
3,4
, K. C. Chambers
36
, William James Chaplin
37,38
, Yen-Chi Chen
39
,
Cristina Chiappini
5,33
, S. Drew Chojnowski
21
, Chia-Hsun Chuang
2
, Nicolas Clerc
40
, Johan Comparat
2
,
Kevin Covey
41,42
, Rupert A. C. Croft
1
, Antonio J. Cuesta
43,44
, Katia Cunha
32,34
, Luiz N. da Costa
32,33
, Nicola Da Rio
45
,
James R. A. Davenport
6
, Kyle S. Dawson
7
, Nathan De Lee
46
, Timothée Delubac
47
, Rohit Deshpande
17,18
,
Saurav Dhital
48
, Letícia Dutra-Ferreira
33,49,50
, Tom Dwelly
40
, Anne Ealet
51
, Garrett L. Ebelke
14
,
Edward M. Edmondson
31
, Daniel J. Eisenstein
52
, Tristan Ellsworth
7
, Yvonne Elsworth
37,38
, Courtney R. Epstein
8
,
Michael Eracleous
6,17,28,53
, Stephanie Escoffier
51
, Massimiliano Esposito
3,4
, Michael L. Evans
6
, Xiaohui Fan
34
,
Emma Fernández-Alvar
3,4
, Diane Feuillet
21
, Nurten Filiz Ak
17,28,54
, Hayley Finley
55
, Alexis Finoguenov
56
,
Kevin Flaherty
57
, Scott W. Fleming
58,59
, Andreu Font-Ribera
12
, Jonathan Foster
44
, Peter M. Frinchaboy
60
,
J. G. Galbraith-Frew
7
, Rafael A. García
61
, D. A. García-Hernández
3,4
, Ana E. García Pérez
3,4,14
, Patrick Gaulme
20
,
Jian Ge
45
, R. Génova-Santos
3,4
, A. Georgakakis
40
, Luan Ghezzi
32,52
, Bruce A. Gillespie
62
, Léo Girardi
33,63
,
Daniel Goddard
31
, Satya Gontcho A Gontcho
43
, Jonay I. González Hernández
3,4
, Eva K. Grebel
64
, Paul J. Green
52
,
Jan Niklas Grieb
40
, Nolan Grieves
45
, James E. Gunn
35
, Hong Guo
7
, Paul Harding
65
, Sten Hasselquist
21
,
Suzanne L. Hawley
6
, Michael Hayden
21
, Fred R. Hearty
17
, Saskia Hekker
38,66
, Shirley Ho
1
, David W. Hogg
24
,
Kelly Holley-Bockelmann
19
, Jon A. Holtzman
21
, Klaus Honscheid
67,68
, Daniel Huber
38,69,70
, Joseph Huehnerhoff
20
,
Inese I. Ivans
7
, Linhua Jiang
71
, Jennifer A. Johnson
8,68
, Karen Kinemuchi
20,21
, David Kirkby
25
, Francisco Kitaura
5
,
Mark A. Klaene
20
, Gillian R. Knapp
35
, Jean-Paul Kneib
47,72
, Xavier P. Koenig
13
, Charles R. Lam
14
, Ting-Wen Lan
62
,
Dustin Lang
1
, Pierre Laurent
10
, Jean-Marc Le Goff
10
, Alexie Leauthaud
73
, Khee-Gan Lee
74
, Young Sun Lee
75
,
Timothy C. Licquia
9
, Jian Liu
45
, Daniel C. Long
20,21
, Martín López-Corredoira
3,4
, Diego Lorenzo-Oliveira
33,49
,
Sara Lucatello
63
, Britt Lundgren
76
, Robert H. Lupton
35
, Claude E. Mack III
5,19
, Suvrath Mahadevan
17,18
,
Marcio A. G. Maia
32,33
, Steven R. Majewski
14
, Elena Malanushenko
20,21
, Viktor Malanushenko
20,21
, A. Manchado
3,4
,
Marc Manera
31,77
, Qingqing Mao
19
, Claudia Maraston
31
, Robert C. Marchwinski
17,18
, Daniel Margala
25
,
Sarah L. Martell
78
, Marie Martig
74
, Karen L. Masters
31
, Savita Mathur
79
, Cameron K. McBride
52
,
Peregrine M. McGehee
80
, Ian D. McGreer
34
, Richard G. McMahon
81,82
, Brice Ménard
62,73,137
, Marie-Luise Menzel
40
,
Andrea Merloni
40
, Szabolcs Mészáros
83
, Adam A. Miller
84,85,138
, Jordi Miralda-Escudé
43,86
, Hironao Miyatake
35,73
,
Antonio D. Montero-Dorta
7
, Surhud More
73
, Eric Morganson
52
, Xan Morice-Atkinson
31
, Heather L. Morrison
65
,
Beno

it Mosser
87
, Demitri Muna
8
, Adam D. Myers
88
, Kirpal Nandra
40
, Jeffrey A. Newman
9
, Mark Neyrinck
62
,
Duy Cuong Nguyen
89
, Robert C. Nichol
31
, David L. Nidever
90
, Pasquier Noterdaeme
55
, Sebastián E. Nuza
5
,
Julia E. O’Connell
60
, Robert W. O’Connell
14
, Ross O’Connell
1
, Ricardo L. C. Ogando
32,33
, Matthew D. Olmstead
7,91
,
Audrey E. Oravetz
20,21
, Daniel J. Oravetz
20
, Keisuke Osumi
1
, Russell Owen
6
, Deborah L. Padgett
92
,
Nikhil Padmanabhan
44
, Martin Paegert
19
, Nathalie Palanque-Delabrouille
10
, Kaike Pan
20
, John K. Parejko
93
,
Isabelle Pâris
94
, Changbom Park
95
, Petchara Pattarakijwanich
35
, M. Pellejero-Ibanez
3,4
, Joshua Pepper
19,96
,
Will J. Percival
31
, Ismael Pérez-Fournon
3,4
, Ignasi Pe

rez-Ra

fols
43,97
, Patrick Petitjean
55
, Matthew M. Pieri
31,98
,
Marc H. Pinsonneault
8
, Gustavo F. Porto de Mello
33,49
, Francisco Prada
2,99,100
, Abhishek Prakash
9
,
Adrian M. Price-Whelan
101
, Pavlos Protopapas
102
, M. Jordan Raddick
62
, Mubdi Rahman
62
, Beth A. Reid
12,103
,
James Rich
10
, Hans-Walter Rix
74
, Annie C. Robin
104
, Constance M. Rockosi
105
, Thaíse S. Rodrigues
33,63,106
,
Sergio Rodríguez-Torres
2,99
, Natalie A. Roe
12
, Ashley J. Ross
31,68
, Nicholas P. Ross
107
, Graziano Rossi
10,108
,
John J. Ruan
6
, J. A. Rubiño-Martín
3,4
, Eli S. Rykoff
109
, Salvador Salazar-Albornoz
40,110
, Mara Salvato
40,111
,
Lado Samushia
112,113
, Ariel G. Sánchez
40
, Basílio Santiago
33,114
, Conor Sayres
6
, Ricardo P. Schiavon
115,116
,
David J. Schlegel
12
, Sarah J. Schmidt
8
, Donald P. Schneider
17,28
, Mathias Schultheis
117
, Axel D. Schwope
5
,
C. G. Scóccola
3,4
, Caroline Scott
52
, Kris Sellgren
8
, Hee-Jong Seo
118
, Aldo Serenelli
119
, Neville Shane
14
,
Yue Shen
15,71
, Matthew Shetrone
120
, Yiping Shu
7
, V. Silva Aguirre
38
, Thirupathi Sivarani
121
, M. F. Skrutskie
14
,
Anže Slosar
122
, Verne V. Smith
123
, Flávia Sobreira
33,124
, Diogo Souto
32
, Keivan G. Stassun
19,125
, Matthias Steinmetz
5
,
Dennis Stello
38,69
, Michael A. Strauss
35,139
, Alina Streblyanska
3,4
, Nao Suzuki
73
, Molly E. C. Swanson
52
,
Jonathan C. Tan
45
, Jamie Tayar
8
, Ryan C. Terrien
17,18,126
, Aniruddha R. Thakar
62
, Daniel Thomas
31,127
, Neil Thomas
45
,
Benjamin A. Thompson
60
, Jeremy L. Tinker
24
, Rita Tojeiro
128
, Nicholas W. Troup
14
, Mariana Vargas-Magaña
1
,
The Astrophysical Journal Supplement Series, 219:12 (27pp), 2015 July doi:10.1088/0067-0049/219/1/12
© 2015. The American Astronomical Society. All rights reserved.
1

Jose A. Vazquez
122
, Licia Verde
43,86,129
, Matteo Viel
94,130
, Nicole P. Vogt
21
, David A. Wake
76,131
, Ji Wang
13
,
Benjamin A. Weaver
24
, David H. Weinberg
8
, Benjamin J. Weiner
34
, Martin White
12,103
, John C. Wilson
14
,
John P. Wisniewski
132
, W. M. Wood-Vasey
9,139
, Christophe Ye

che
10
, Donald G. York
133
, Nadia L. Zakamska
62
,
O. Zamora
3,4
, Gail Zasowski
62
, Idit Zehavi
65
, Gong-Bo Zhao
31,134
, Zheng Zheng
7
, Xu Zhou (周旭)
135
,
Zhimin Zhou (周志民)
135
, Hu Zou (邹虎)
135
, and Guangtun Zhu
62,138
1
McWilliams Center for Cosmology, Department of Physics, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA
2
Instituto de Física Teórica, (UAM/CSIC), Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid, Spain
3
Instituto de Astrofísica de Canarias (IAC), C/Vía Láctea, s/n, E-38200, La Laguna, Tenerife, Spain
4
Departamento de Astrofísica, Universidad de La Laguna, E-38206, La Laguna, Tenerife, Spain
5
Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany
6
Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
7
Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112, USA
8
Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210, USA
9
PITT PACC, Department of Physics and Astronomy, University of Pittsburgh, 3941 O’Hara Street, Pittsburgh, PA 15260, USA
10
CEA, Centre de Saclay, Irfu/SPP, F-91191 Gif-sur-Yvette, France
11
APC, University of Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, F-75205 Paris, France
12
Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA
13
Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101, USA
14
Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325, USA
15
Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101, USA
16
Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556, USA
17
Department of Astronomy and Astrophysics, 525 Davey Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
18
Center for Exoplanets and Habitable Worlds, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802, USA
19
Department of Physics and Astronomy, Vanderbilt University, VU Station 1807, Nashville, TN 37235, USA
20
Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349, USA
21
Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003, USA
22
Sternberg Astronomical Institute, Moscow State University, Universitetskij Prosp. 13, Moscow 119992, Russia
23
University of Pennsylvania, Department of Physics and Astronomy, 219 South 33rd Street, Philadelphia, PA 19104, USA
24
Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003, USA
25
Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA
26
Rider University, 2083 Lawrenceville Road, Lawrenceville, NJ 08648, USA
27
Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540, USA
28
Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
29
Department of Physics, The Pennsylvania State University, University Park, PA 16802, USA
30
George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University,
Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843, USA
31
Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX, UK
32
Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ—20921-400, Brazil
33
Laboratório Interinstitucional de e-Astronomia, - LIneA, Rua Gal.José Cristino 77, Rio de Janeiro, RJ —20921-400, Brazil
34
Steward Observatory, 933 North Cherry Avenue, Tucson, AZ 85721, USA
35
Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
36
Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822, USA
37
School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
38
Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark
39
Department of Statistics, Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
40
Max-Planck-Institut für Extraterrestrische Physik, Postfach 1312, Giessenbachstrasse D-85741 Garching, Germany
41
Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff AZ 86001, USA
42
Western Washington University, Department of Physics & Astronomy, 516 High Street, Bellingham WA 98225, USA
43
Institut de Ciències del Cosmos, Universitat de Barcelona/IEEC, Barcelona E-08028, Spain
44
Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT, 06520, USA
45
Department of Astronomy, University of Florida, Bryant Space Science Center, Gainesville, FL 32611-2055, USA
46
Department of Physics and Geology, Northern Kentucky University, Highland Heights, KY 41099, USA
47
Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290, Versoix, Switzerland
48
Department of Physical Sciences, Embry-Riddle Aeronautical University, 600 South Clyde Morris Boulevard, Daytona Beach, FL 32114, USA
49
Universidade Federal do Rio de Janeiro, Observatório do Valongo, Ladeira do Pedro Antônio 43, 20080-090 Rio de Janeiro, Brazil
50
Departamento de Física, Universidade Federal do Rio Grande do Norte, 59072-970, Natal, RN, Brazil
51
Centre de Physique des Particules de Marseille, Aix-Marseille Université, CNRS/IN2P3, F-13288 Marseille, France
52
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge MA 02138, USA
53
Center for Relativistic Astrophysics, Georgia Institute of Technology, Atlanta, GA 30332, USA
54
Faculty of Sciences, Department of Astronomy and Space Sciences, Erciyes University, 38039 Kayseri, Turkey
55
Institut d’Astrophysique de Paris, UPMC-CNRS, UMR7095, 98 bis Boulevard Arago, F-75014, Paris, France
56
Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2, Helsinki FI-00140, Finland
57
Department of Astronomy, Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA
58
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
59
Computer Sciences Corporation, 3700 San Martin Drive, Baltimore, MD 21218, USA
60
Department of Physics and Astronomy, Texas Christian University, 2800 South University Drive, Fort Worth, TX 76129, USA
61
Laboratoire AIM, CEA/DSM—CNRS—Univ. Paris Diderot—IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex, France
62
Center for Astrophysical Sciences, Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA
63
INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy
64
Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstrasse 12-14, D-69120 Heidelberg, Germany
65
Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106, USA
66
Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen, Germany
67
Department of Physics, Ohio State University, Columbus, OH 43210, USA
68
Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210, USA
69
Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, Sydney, NSW 2006, Australia
2
The Astrophysical Journal Supplement Series, 219:12 (27pp), 2015 July Alam et al.

70
SETI Institute, 189 Bernardo Avenue, Mountain View, CA 94043, USA
71
Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871, China
72
Laboratoire d’Astrophysique de Marseille, CNRS-Université de Provence, 38 rue F. Joliot-Curie, F-13388 Marseille cedex 13, France
73
Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), Todai Institutes for Advanced Study,
The University of Tokyo, Kashiwa,
277-8583, Japan
74
Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
75
Department of Astronomy and Space Science Chungnam National University Daejeon 305-764, Korea
76
Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street, Madison WI 53703, USA
77
University College London, Gower Street, London, WC1E 6BT, UK
78
School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
79
Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA
80
IPAC, MS 220-6, California Institute of Technology, Pasadena, CA 91125, USA
81
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
82
Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
83
ELTE Gothard Astrophysical Observatory, H-9704 Szombathely, Szent Imre herceg st. 112, Hungary
84
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
85
Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
86
Institució Catalana de Recerca i Estudis Avançats, Barcelona E-08010, Spain
87
LESIA, UMR 8109, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, F-92195 Meudon Cedex, France
88
Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
89
Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON, M5S 3H4, Canada
90
Dept. of Astronomy, University of Michigan, Ann Arbor, MI, 48104, USA
91
Department of Chemistry and Physics, King’s College, Wilkes-Barre, PA 18711, USA
92
NASA/GSFC, Code 665, Greenbelt, MC 20770, USA
93
Department of Physics, Yale University, 260 Whitney Avenue, New Haven, CT, 06520, USA
94
INAF, Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste, Italy
95
School of Physics, Korea Institute for Advanced Study, 85 Hoegiro, Dongdaemun-gu, Seoul 130-722, Korea
96
Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, PA 18015, USA
97
Departament d’Astronomia i Meteorologia, Facultat de Física, Universitat de Barcelona, E-08028 Barcelona, Spain
98
A*MIDEX, Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, F-13388 Marseille cedex 13, France
99
Campus of International Excellence UAM+CSIC, Cantoblanco, E-28049 Madrid, Spain
100
Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, E-18080 Granada, Spain
101
Department of Astronomy, Columbia University, New York, NY 10027, USA
102
Institute for Applied Computational Science, SEAS, Harvard University, 52 Oxford Street, Cambridge, MA 02138, USA
103
Department of Physics, University of California, Berkeley, CA 94720, USA
104
Université de Franche-Comté, Institut Utinam, UMR CNRS 6213, OSU Theta, Besançon, F-25010, France
105
Department of Astronomy and Astrophysics, University of California, Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
106
Dipartimento di Fisica e Astronomia, Università di Padova, Vicolo dell’Osservatorio 2, I-35122 Padova, Italy
107
Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104, USA
108
Department of Astronomy and Space Science, Sejong University, Seoul, 143-747, Korea
109
SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
110
Universitäts-Sternwarte München, Scheinerstrasse 1, D-81679 Munich, Germany
111
Cluster of Excellence, Boltzmannstraße 2, D-85748 Garching, Germany
112
Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA
113
National Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave., GE-1060 Tbilisi, Georgia
114
Instituto de Física, UFRGS, Caixa Postal 15051, Porto Alegre, RS—91501-970, Brazil
115
Gemini Observatory, 670 N. A’Ohoku Place, Hilo, HI 96720, USA
116
Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF, UK
117
Université de Nice Sophia-Antipolis, CNRS, Observatoire de Côte d’Azur, Laboratoire Lagrange, BP 4229, F-06304 Nice Cedex 4, France
118
Department of Physics and Astronomy, Ohio University, 251B Clippinger Labs, Athens, OH 45701, USA
119
Instituto de Ciencias del Espacio (CSIC-IEEC), Facultad de Ciencias, Campus UAB, E-08193, Bellaterra, Spain
120
University of Texas at Austin, Hobby-Eberly Telescope, 32 Fowlkes Road, McDonald Observatory, TX 79734-3005, USA
121
Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034, India
122
Brookhaven National Laboratory, Bldg 510, Upton, NY 11973, USA
123
National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ, 85719, USA
124
Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510, USA
125
Department of Physics, Fisk University, 1000 17th Avenue North, Nashville, TN 37208, USA
126
The Penn State Astrobiology Research Center, Pennsylvania State University, University Park, PA 16802, USA
127
SEPnet, South East Physics Network, UK
128
School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, KY16 9SS, UK
129
Institute of Theoretical Astrophysics, University of Oslo, NO-0315 Oslo, Norway
130
INFN/National Institute for Nuclear Physics, Via Valerio 2, I-34127 Trieste, Italy
131
Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK
132
H.L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019, USA
133
Department of Astronomy and Astrophysics and the Enrico Fermi Institute, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA
134
National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China
135
Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012, China
Received 2015 January 7; accepted 2015 April 2; published 2015 July 27
136
John Bahcall Fellow.
137
Alfred P. Sloan Fellow.
138
Hubble Fellow.
139
Corresponding authors.
3
The Astrophysical Journal Supplement Series, 219:12 (27pp), 2015 July Alam et al.

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 of 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 deg
2
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 the measured abundances of 15 different elements for each
star. In total, SDSS-III added 5200 deg
2
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 deg
2
; 618,080 APOGEE spectra of 156,593 stars; and
197,040 MARVELS spectra of 5513 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.
Key words: atlases – catalogs – surveys
1. INTRODUCTION
Comprehensive wide-field imaging and spectroscopic sur-
veys of the sky have played a key role in astronomy, leading to
fundamental new breakthroughs in our understanding of the
Solar System; our Milky Way Galaxy and its constituent stars
and gas; the nature, properties, and evolution of galaxies; and
the universe as a whole. The Sloan Digital Sky Survey (SDSS),
which started routine operations in 2000 April, has carried out
imaging and spectroscopy over roughly 1/3 of the Celestial
Sphere. SDSS uses a dedicated 2.5 m wide-field telescope
(Gunn et al. 2006), instrumented with a sequence of
sophisticated imagers and spectrographs. The SDSS has gone
through a series of stages. SDSS-I (York et al. 2000), which
was in operation through 2005, focused on a “Legacy” survey
of five-band imaging (using what was at the time the largest
camera ever used in optical astronomy; Gunn et al. 1998) and
spectroscopy of well-defined samples of galaxies (Eisenstein
et al. 2001; Strauss et al. 2002) and quasars (Richards
et al. 2002), using a 640 fiber pair of spectrographs (Smee
et al. 2013). SDSS-II operated from 2005 to 2008 and finished
the Legacy survey. It also carried out a repeated imaging
survey of the Celestial Equator in the Fall sky to search for
supernovae (Frieman et al. 2008), as well as a spectroscopic
survey of stars to study the structure of the Milky Way (Yanny
et al. 2009).
SDSS-III (Eisenstein et al. 2011) started operations in Fall
2008, completing in Summer 2014. SDSS-III consisted of four
interlocking surveys.
1. The Sloan Exploration of Galactic Understanding and
Evolution 2
(SEGUE-2; C. Rockosi et al. 2015, in
preparation) used the SDSS-I/II spectrographs to obtain
R
2000∼
spectra of stars at high and low Galactic
latitudes to study Galactic structure, dynamics, and stellar
populations. SEGUE-2 gathered data during the
2008–2009 season.
2. The Baryon Oscillation Spectroscopic Survey (BOSS;
Dawson et al. 2013) used the SDSS imager to increase
the footprint of SDSS imaging in the southern Galactic
Cap in the 2008–2009 season. The SDSS spectrographs
were then completely rebuilt with new fibers (2″ entrance
aperture rather than 3″, 1000 fibers per exposure) as well
as new gratings, CCDs, and optics. Galaxies (B. Reid et
al. 2015, in preparation) and quasars (Ross et al. 2012)
were selected from the SDSS imaging data, and are used
to study the baryon oscillation feature in the clustering of
galaxies (Anderson et al. 2014a, 2014c) and Lyα
absorption along the line of sight to distant quasars
(Busca et al. 2013; Slosar et al. 2013; Font-Ribera
et al. 2014; Delubac et al. 2015). BOSS collected
spectroscopic data from 2009 December to 2014 July.
3. The Apache Point Observatory Galaxy Evolution Experi-
ment (APOGEE; S. Majewski et al. 2015, in preparation)
used a separate 300 fiber high-resolution (
R
∼
22,500),
H-band spectrograph to investigate the composition and
dynamics of stars in the Galaxy. The target stars were
selected from the 2MASS database (Skrutskie
et al. 2006); the resulting spectra give highly accurate
stellar surface temperatures, gravities, and detailed
abundance measurements. APOGEE gathered data from
2011 May to 2014 July.
4. The Multi-object APO Radial Velocity Exoplanet Large-
area Survey (MARVELS; J. Ge et al. 2015, in prepara-
tion) used a 60 fiber interferometric spectrograph to
measure the high-precision radial velocities (RVs) of
stars to search for extra-solar planets and brown dwarfs
orbiting them. MARVELS gathered data from 2008
October to 2012 July.
The SDSS data have been made available to the scientific
community and the public in a roughly annual cumulative
series of data releases. These data have been distributed
(Thakar 2008b) in the form of direct access to raw and
processed imaging and spectral files and also through a
relational database (the “Catalog Archive Server,” or
“CAS”), presenting the derived catalog information. As of
DR12, these catalogs present information on a total of ∼470
million objects in the imaging survey and 5.3 million spectra.
The Early Data Release (EDR; Stoughton et al. 2002) and
Data Releases 1–5 (DR1; Abazajian et al. 2003, DR2;
Abazajian et al. 2004, DR3; Abazajian et al. 2005, DR4;
Adelman-McCarthy et al. 2006, and DR5; Adelman-McCarthy
et al. 2007) included data from SDSS-I. DR6 and DR7
(Adelman-McCarthy et al. 2008; Abazajian et al. 2009)
4
The Astrophysical Journal Supplement Series, 219:12 (27pp), 2015 July Alam et al.

covered the data in SDSS-II. The data from SDSS-III have
appeared in three releases thus far. DR8 (Aihara et al. 2011)
included the final data from the SDSS imaging camera, as well
as all the SEGUE-2 data. DR9 (Ahn et al. 2012) included the
first spectroscopic data from BOSS. DR10 (Ahn et al. 2014)
roughly doubled the amount of BOSS data made public and
included the first release of APOGEE data.
The SDSS-III collaboration has found it useful to internally
define a data set associated with the data taken through 2013
Summer, which we designate as “DR11.” The SDSS-III
completed data-taking in 2014 July, and the present paper
describes both DR11 and Data Release 12 (DR12). Like
previous data releases, DR12 is cumulative; it includes all of
the data taken by SDSS to date. DR12 includes almost 2.5
million BOSS spectra of quasars, galaxies, and stars over 9376
square degrees: 155,000 SEGUE-2 spectra of 138,000 stars (as
released in DR8), and 618,000 APOGEE spectra of 156,000
stars. It also includes the first release of MARVELS data,
presenting 197,000 spectra of 5500 stars (3300 stars with
16>
observations each). Because some BOSS, APOGEE, and
MARVELS scientific papers have been based on the DR11
sample, this paper describes the distinction between DR11 and
DR12 and the processing software for the two data sets, and
how to understand this distinction in the database.
The data release itself may be accessed from the SDSS-III
website
140
or the DR12 page of the new pan-SDSS website.
141
DR11 is similarly available through the same interfaces. The
outline of this paper is as follows. We summarize the full
contents of DR11 and DR12 in Section 2, emphasizing the
quantity of spectra and the solid angle covered by each of the
surveys. Details for each component of SDSS-III are described
in Section 3 (MARVELS), Section 4 (BOSS), and Section 5
(APOGEE). There have been no updates to SEGUE-2 since
DR9 and we do not discuss it further in this paper. We describe
the distribution of the data in Section 6 and conclude, with a
view to the future, in Section 7.
2. SUMMARY OF COVERAGE
DR12 presents all of the data gathered by SDSS-III, which
extended from 2008 August to 2014 June, plus a small amount
of data gathered using the BOSS and APOGEE instruments in
the first two weeks of 2014 July under the auspices of the next
phase of the SDSS, SDSS-IV (see Section 7). The contents of
the data release are summarized in Table 1 and described in
detail in the sections that follow for each component survey of
the SDSS-III.
As described in Section 4, the BOSS spectroscopy is now
complete in two large contiguous regions in the northern and
southern Galactic caps. DR12 represents a
40%
∼
increment
over the previous data release (DR10). The first public release
of APOGEE data (Section 5) was in DR10; DR12 represents
more than a three-fold increase in the number of spectra, and
six times as many stars with 12 or more visits. In addition,
DR12 includes the first release of data from MARVELS.
MARVELS was in operation for four years (2008–2012); all
resulting data are included in the release. The MARVELS data
(Section 3) include ∼5500 unique stars, most of which have
20–40 observations (and thus RV measurements) per star.
DR11 and DR12 represent different pipeline processing of the
Table 1
Contents of DR11 and DR12
DR11 DR12
Total Unique
a
Total Unique
a
All SDSS Imaging and Spectroscopy
Area Imaged
b
(deg
2
) 31637 14555
Cataloged Objects
b
1231051050 469053874
Total Spectra 5256940 L
Total Useful Spectra
p
5072804 4084671
MARVELS Spectroscopy (Interferometric)
Plates
c
1581 241 1642 278
Spectra
d
189720 3533 197040 5513
Stars with ⩾16 Visits L 2757 L 3087
APOGEE Spectroscopy (NIR)
Plates 1439 547 2349 817
Pointings L 319 L 435
All Stars
e
377812 110581 618080 156593
Stars observed with
NMSU 1 m
LL 1196 882
Commissioning Stars 27660 12140 27660 12140
Survey Stars
f
353566 101195 590420 149502
Stars with S/N
100>
g
L 89207 L 141320
Stars with
3⩾
Visits L 65454 L 120883
Stars with
1
2
⩾
Visits L 3798 L 6107
Stellar Parameter
Standards
7657 1151 8307 1169
Radial Velocity
Standards
202 16 269 17
Telluric Line
Standards
46112 10741 83127 17116
Ancillary Science
Program Objects
20416 6974 36123 12515
Kepler Target Stars
h
11756 6372 15242 7953
BOSS Spectroscopy (Optical)
Spectroscopic
Effective area (deg
2
)
L 8647 L 9376
Plates
i
2085 2053 2512 2438
Spectra
j
2074036 1912178 2497484 2269478
All Galaxies 1281447 1186241 1480945 1372737
CMASS
k
825735 763498 931517 862735
LOWZ
k
316042 294443 368335 343160
All Quasars 262331 240095 350793 294512
Main
l
216261 199061 241516 220377
Main,
z
2
.15 3.5⩽⩽
m
156401 143377 175244 158917
Ancillary Spectra 154860 140899 308463 256178
Stars 211158 190747 274811 247216
Standard Stars 41868 36246 52328 42815
Sky 195909 187644 238094 223541
Unclassified Spectra
n
132476 115419 163377 140533
SEGUE-2
b
Spectroscopy (Optical)
Spectroscopic effective
area (deg
2
)
L 1317
Plates 229
Spectra LL155520 138099
All Optical
o
Spectroscopy from SDSS as of DR12
Total Spectra 4355200
140
http://www.sdss3.org/dr12
141
http://www.sdss.org/dr12
5
The Astrophysical Journal Supplement Series, 219:12 (27pp), 2015 July Alam et al.

Frequently asked questions

Q1. What have the authors contributed in "The eleventh and twelfth data releases of the sloan digital sky survey: final data from sdss-iii" ?

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. 

Q2. What are the future works in "The eleventh and twelfth data releases of the sloan digital sky survey: final data from sdss-iii" ?

The SDSS-IV Mapping Nearby Galaxies at APO ( MaNGA ) program ( Bundy et al. 2015 ) will revisit 10,000 of these galaxies in far greater detail using integral-field fiber bundles to study spatially resolved galaxy properties, star formation, and evolution. The data provide a census of YSO into the brown dwarf regime, a measurement of the initial mass function at low masses, and a characterization of circumstellar disks as a function of stellar mass, extending previous studies to fainter magnitudes, to be sensitive to very low luminosity, low-mass objects. In addition, a second APOGEE instrument will be built and installed on the 2. 5 m du Pont Telescope at Las Campanas Observatory, Chile, providing an all-sky view of the Galaxy. All BOSS ancillary programs initiated after 2012 can be identified by having a non-zero ANCILLARY_TARGET2 bitmask. 

Q3. What is the purpose of the Sloan Digital Sky Survey?

Comprehensive wide-field imaging and spectroscopic surveys of the sky have played a key role in astronomy, leading to fundamental new breakthroughs in their understanding of the Solar System; their Milky Way Galaxy and its constituent stars and gas; the nature, properties, and evolution of galaxies; and the universe as a whole. 

Q4. How many fkk stars were selected in the SDSS telescope?

The MARVELS fields were selected to have 90> FGK stars with V 12< and 30 giant stars withV 11< in the SDSS telescope 3° diameter field of view. 

Q5. What is the purpose of the SDSS?

SDSS uses a dedicated 2.5 m wide-field telescope (Gunn et al. 2006), instrumented with a sequence of sophisticated imagers and spectrographs. 

Q6. What is the name of the project?

4. The Multi-object APO Radial Velocity Exoplanet Largearea Survey (MARVELS; J. Ge et al. 2015, in preparation) used a 60 fiber interferometric spectrograph to measure the high-precision radial velocities (RVs) of stars to search for extra-solar planets and brown dwarfs orbiting them. 

Q7. What is the purpose of the DR12 release?

In addition, prototype and commissioning data were obtained during SDSS-III for the SDSS-IV Mapping Nearby Galaxies at APO (MaNGA) project (Bundy et al. 2015), which uses the BOSS spectrographs to measure spatially resolved spectra across galaxies. 

Q8. What data were collected from the Apache Point Observatory?

The target stars were selected from the 2MASS database (Skrutskie et al. 2006); the resulting spectra give highly accurate stellar surface temperatures, gravities, and detailed abundance measurements. 

Q9. How many unique stars are included in DR12?

The MARVELS data (Section 3) include ∼5500 unique stars, most of which have 20–40 observations (and thus RV measurements) per star. 

Q10. What was the purpose of the observations?

These observations of a single star at a time were taken to extend the range of the APOGEE-observed stars to brighter limits, providing improved calibration with existing observations of these stars (see Holtzman et al. 2015, for details).