Technical Papers and Additional References

• Journals of the American Astronomical Society (AAS):
  • Instructions for using Facilities Keywords
    Example: \facilities{Du Pont (APOGEE), Sloan (APOGEE), Spitzer, WISE, 2MASS, Gaia}
  • Instructions for using Software Keywords
• Astronomy & AstroPhysics (A&A):
  • Astronomer's Source Code Library (ASCL) Citation Instructions
• Monthly Notices of the Royal Astronomical Society (MNRAS):
  • MNRAS Data Policy

DR17 Data Release Description

Abdurro’uf et al. (2022) is the latest SDSS-IV data release paper, describing SDSS Data Release 17. The latest data release paper should always be used as the primary reference for most uses of SDSS data.

DR17 Pipeline and Data Release Description and Validation

Holtzman et al. (in prep.) provides extensive detail with regard to DR16-related modifications of the data reduction and ASPCAP pipelines and evaluates all DRP- and ASPCAP-generated data products (e.g., radial velocity values, stellar atmospheric parameters and individual element abundances).

APOGEE Overview

Majewski et al. (2017) discusses the scientific motivation for the APOGEE-1 survey, the survey requirements, and the choice of survey fields. It describes survey operations, summarizes the level to which requirements are met, and references the data releases. Much of this information remains highly relevant for APOGEE-2.

APOGEE-2 Overview

Majewski et al. (in prep.) discusses the scientific motivation for the APOGEE-2 survey, its survey requirements, and choices relating to the programs that were initiated. It describes dual hemisphere survey operations, summarizes the level to which requirements are met, and references the data releases.

SDSS 2.5m Telescope

Gunn et al. (2006) describes the technical setup for the SDSS 2.5-meter telescope.

NMSU 1m Telescope

Holtzman et al. (2010) describes the technical setup for the NMSU 1-meter telescope.

LCO 2.5m Telescope

Bowen and Vaughan (1973) describes the optical design of the Irénée du Pont Telescope at Las Campanas Observatory.

The APOGEE Instruments

Wilson et al. (2019) describes the technical details of the APOGEE-N and APOGEE-S instruments, themselves, and present instrument performance data. Prior to DR16, the reference was Wilson et al. (2012).

Fiber Development and FRD Testing

Brunner et al. (2010) describes technical details about the APOGEE fibers, optimization concerns, and testing the focal ratio degradation (FRD) required for the instrument.

VPH Grating

Arns et al. (2010) discusses the technical details of the VPH grating.

The Cryostat

Blank et al. (2010) describes technical considerations for and the design of the APOGEE cyrostat.

APOGEE-1 Target Selection

Zasowski et al. (2013) discusses the target selection for main survey and APOGEE-1 ancillary science projects.

• Pinsonneault et al. (2014) provide an expanded discussion of the Kepler field targeting (APOKASC).
• Cottaar et al. 2014 describes the IN-SYNC ancillary program in APOGEE-1.
• Frinchaboy et al. 2013 describes the Open Cluster Chemical Abundance and Mapping survey (OCCAM) and includes a detailed discussion of the targeting algorithms.

APOGEE-2 Target Selection

Zasowski et al. (2017) describes the APOGEE-2 field plan and explains in detail the targeting strategy employed for APOGEE-2N and APOGEE-2S.

• Pinsoneault et al. (2018) provides updates to the APOKASC program in APOGEE-2.
• Cottle et al. (2018) describes the target selection for the Young Clusters program in APOGEE-2.
• Nidever et al. (2020) describes the target selection for the Magellanic Clouds program in APOGEE-2. Though we note substantial expansions are described in Santana et al. (2021).
• Donor et al. (2018) provides an update for the Open Cluster Chemical Abundance and Mapping survey (OCCAM), including revisions to the target selection using early releases from Gaia.

Final APOGEE-2N Target Selection

Beaton et al. (2021) describes the final APOGEE-2N field plan, special programs in APOGEE-2N, and modifications to the target selection strategy undertaken to reach survey goals.

Final APOGEE-2S Target Selection

Santana et al. (2021) describes the final APOGEE-2S field plan, special programs in APOGEE-2S, and modifications to the target selection strategy undertaken to reach survey goals.

APOGEE Data Reduction

Nidever et al. (2015) discusses the data reduction pipeline, describing how the raw data are analyzed to produce reduced, calibrated spectra. It also presents additional instrument performance data (flats, darks, LSF, persistence, etc.) and discusses the measurement of radial velocities and their quality.

• In DR17, a new procedure, "Doppler," was adopted for RV Measurements. This code is also available on github: github/dnidever/doppler
• The specific implementation of these codes for APOGEE data are available on github/sdss/apogee

NMSU 1-meter Data Processing

Holtzman et al. (2015) has sections discussing the 1-meter data processing, which differs slightly from that in the main survey.

Radial Velocity Validation

The following papers address specific expansions or applications of our RV results that may be useful for other science applications:

• Deshpande et al. (2013) discusses specific requirements for the determination of M-dwarf stars with APOGEE data.
• Badenes et al. (2018) use the variation of RV for the APOGEE sample as a means to draw inference on the binary population. Technical descriptions and testing conducted in this paper are useful for evaluating the RV precision and variability.
• Price-Whelan et al. (2018, 2020, in prep.) use the individual epoch RVs to identify multiple star systems using The Joker (Price-Whelan et al. 2017, ASCL Entry, GitHub). Technical descriptions and testing conducted in this paper are useful for evaluating the RV precision and variability.
  In DR16 and DR17, a Value-Added Catalog applied these methods to the full dataset and made those results fully public.

ASPCAP Overview

Garcia Perez et al. (2016) describes how the spectra are analyzed to derive stellar parameters and abundances. It demonstrates validation of the overall method using simulated data and discusses uncertainties that are introduced by real-world issues: SNR, issues related computational efficiency, variation and uncertainty of the LSF, and issues involving the loss of information under skylines. It presents some basic tests of the methodology from very-high-resolution observations of some well-studied stars.

• The ASPCAP code is available on github/sdss/apogee

APOGEE Model Atmospheres

Jönsson et al. (2020) describes the model grid and the interpolation methods that were adopted in DR16 and DR17.

• DR17 uses MARCS atmospheres: Gustafsson et al. (2008).
• Prior to DR16, Meszaros et al. (2012) discusses details of the model atmospheres that were used.

APOGEE Line List

The line list used for DR16 and DR17 was significantly expanded from previous efforts, this is described in Smith et al. (2021).
Additional papers discussing the line list development are as follows:

• The line list used for DR10-DR15 was described in Shetrone et al. (2015) , which also presents the details of how the H-band linelists, a critical component for ASPCAP, were developed.
• The APOGEE linelists were tested using high-resolution IR spectra of several well-studied stars in Smith et al. (2013).
• Further tests of the individual elements derived from the ASPCAP pipeline are found in Cunha et al. (2015).
• The identification and characterization of Neodymium is described in Hasselquist et al. (2016).
• The identification and characterization of Cerium is described Cunha et al. (2017)

APOGEE Spectral Grids

The DR17 spectral grids are described in Holtzman et al. (in prep). Additional supporting publications are:

• Non-Local Thermodynamical Equilibrium (NLTE) calculations for Na, Ca, Mg, and K as described in Osorio et al. (2020).
• Some of our spectral grids used the Synspec code, which is available on the Synspec Website. The code was published in the ASCL as Hubeny & Lanz (2011) with a User's Guide Hubeny & Lanz (2017).
• In DR17, we also used Turbospectrum. Turbospectrum was published to the ASCL as Plez (2012) and requests that Alvarez & Plez (1998) also be cited. Turbuospectrum is available on github

Other papers describing the development of the spectral grids are as follows:

• The DR16 grids were described by Jönsson et al. (2020).
• Prior to DR16, Zamora et al. (2015) presents how the spectral synthesis was done, documents the libraries that have been used, and investigates the sensitivity of the result to the choice of synthesis code and model atmospheres.
• Mezaros et al. 2012 presented additional supporting material for the APOGEE spectral grids.

FERRE

Allende Prieto et al. (2006) describes FERRE, which is the spectral fitting engine used for ASPCAP. The code is available on github with its own documentation available (pdf; updated regularly).

The Cannon

The Cannon is described in Ness et al. (2015) and Casey et al. (2016).

APOGEE DR10 Calibration

Meszaros et al. (2013) discusses calibration of stellar parameters that were released in DR10.

APOGEE DR12 Data

Holtzman et al. (2015) describes the APOGEE data contained in DR12 of in SDSS-III.

APOGEE DR13/DR14 Data

Holtzman et al. (2018) provides extensive detail with regard to DR13- and DR14-related modifications of the data reduction and ASPCAP pipelines and evaluates all DRP- and ASPCAP-generated data products (e.g., radial velocity values, stellar atmospheric parameters and individual element abundances).

DR13/DR14 Validation

Jönsson et al. (2018) compares DR13 and DR14 ASPCAP-derived parameters with various optical abundance analyses from the literature.

DR16 Data

Jönsson et al. (2020) is the DR16 data release paper that describes the processing and data analysis employed.

DR17 Data

Holtzman et al. (in prep.) is the DR17 APOGEE data release paper that describes the processing and data analysis employed.

Gaia Mission

Gaia Collaboration, Prusti et al. (2016) provides a description of the Gaia mission, including the spacecraft, instruments, survey, and measurement principles.

Gaia EDR3

• Gaia Collaboration, Brown et al. (2021): Summary of the contents and survey properties for Gaia Early Data Release 3
• Please review the Credit and Citation Requirements for Gaia EDR3
• In addition to the specific references listed below, users should consult the full repository of Gaia Early Data Release 3 Papers to ensure proper referencing in their work.

Gaia EDR3 Astrometry

Lindegren et al. (2021) provides the description of the Gaia EDR3 Astrometric Solution.

Gaia EDR3 Photometry

Riello et al. (2021) provides a description of the Gaia EDR3 Photometric System.

Gaia EDR3 Radial Velocities

Seabroke et al. (2021) provides a description of the updates to the Gaia DR2 radial velocities as presented in Gaia EDR3.

Distances

Bailer-Jones et al. (2021) is a catalog of geometric distances derived from Gaia EDR3 parallax data using rigorous statistical methods.

2MASS

The canonical paper for 2MASS is Skrutskie et al. (2006) and the acknowledgement is provided on the 2MASS IPAC webpage.

WISE

Wright et al. (2010) describes the WISE mission and spacecraft and the AllWise catalog is cited as Cutri et al. (2013). The acknowledgement is provided on the WISE2 IPAC Webpage and the AllWise IPAC Webpage.

Spitzer

Werner et al. (2004) describes the Spitzer Space Telescope and Mission. The IRAC instrument is described in Fazio et al. (2004). In particular, APOGEE targeting in the disk and Bulge makes use of data products from Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE). Acknowledgements for Spitzer are described on the Spitzer IRAC Webpage.

Washington+DDO51

The Washington+DDO51 photometry included in the summary files is described in Zasowksi et al. (2013).
Those using these data may also include the following acknowledgement: "The APOGEE project thanks Jeff Munn (NOFS) for collecting Washington$+DDO51$ imaging for large areas of the sky."

$E(B-V)$

$E(B-V)$ estimates are provided from the maps of Schlegel, Finkbeiner, and Davis (1998).

RJCE

The Rayleigh-Jeans Color Excess method is also employed to estimate $A_{K}$ using 2MASS with either WISE or Spitzer photometry and the method is described in Majewski, Zasowski, and Nidever (2011) with some additional modifications described in Zasowksi et al. (2013).

The Targeting Team has provided a DR17 H_SRC Table (PDF with hyperlinks) that provides the SRC_H values, a description of the source and the application, and the appropriate references, when possible. This Table was constructed from the intermediate targeting files and, thus, includes all input SRC_H values irregardless of if they appear in the final output catalogs.

The Targeting Team has provided a DR17 TARG_PM_SRC Table (PDF with Hyperlinks) that provides the TARG_PM_SRC values, a description of the source and the application, and the appropriate references, when possible. This Table was constructed from the intermediate targeting files and, thus, includes all input TARG_PM_SRC values irregardless of if they appear in the final output catalogs.