The Tenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Apache Point Observatory Galactic Evolution Experiment (1307.7735v3)

Abstract: The Sloan Digital Sky Survey (SDSS) has been in operation since 2000 April. This paper presents the tenth public data release (DR10) from its current incarnation, SDSS-III. This data release includes the first spectroscopic data from the Apache Point Observatory Galaxy Evolution Experiment (APOGEE), along with spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS) taken through 2012 July. The APOGEE instrument is a near-infrared R~22,500 300-fiber spectrograph covering 1.514--1.696 microns. The APOGEE survey is studying the chemical abundances and radial velocities of roughly 100,000 red giant star candidates in the bulge, bar, disk, and halo of the Milky Way. DR10 includes 178,397 spectra of 57,454 stars, each typically observed three or more times, from APOGEE. Derived quantities from these spectra (radial velocities, effective temperatures, surface gravities, and metallicities) are also included.DR10 also roughly doubles the number of BOSS spectra over those included in the ninth data release. DR10 includes a total of 1,507,954 BOSS spectra, comprising 927,844 galaxy spectra; 182,009 quasar spectra; and 159,327 stellar spectra, selected over 6373.2 square degrees.

• The paper integrates APOGEE’s high-resolution infrared spectra with BOSS’s expansive survey to enhance our understanding of Galactic structure.
• It applies advanced calibration methods to accurately measure stellar parameters, radial velocities, and elemental abundances from over 57,000 star spectra.
• The study significantly expands the spectroscopic dataset, doubling previous releases and paving the way for future, more comprehensive surveys.

Overview of the Sloan Digital Sky Survey's Tenth Data Release

The tenth data release (DR10) from the Sloan Digital Sky Survey-III (SDSS-III) represents a significant milestone in contemporary astronomical research. This release, marked by its incorporation of robust spectroscopic data from both the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the Baryon Oscillation Spectroscopic Survey (BOSS), signifies an important augmentation in our understanding of galactic structure and evolution.

Data and Methodology

The release includes crucial spectroscopic data from the APOGEE instrument, an advanced 300-fiber, near-infrared spectrograph featuring a high resolution of $R \sim 22,500$. APOGEE's survey strategy focuses on studying the chemical abundances and radial velocities of approximately 100,000 red giant stars across diverse sections of the Milky Way, effectively capturing data from the bulge, bar, disk, and halo. The DR10 release encompasses over 57,000 unique star spectra — notably, it comprises 178,397 individual spectra derived from repeat observations to facilitate radial velocity precision and enhance signal-to-noise ratios.

Complementing the APOGEE data, the BOSS component of DR10 expands upon previous data releases by incorporating a remarkable total of 1,507,954 spectra, incorporating 927,844 galaxy spectra, 182,009 quasar spectra, and 159,327 stellar spectra. This augmentation is derived from a significant increase in observational scope, covering 3100 additional square degrees, and effectively doubling the spectroscopic data from the ninth data release.

Key Findings

The data obtained through BOSS continues to aid in constraining cosmological models using the baryon oscillation signature. Meanwhile, the APOGEE data facilitates intricate examinations of the Milky Way's structure and sub-components via its detailed chemical abundance surveys.

APOGEE's data analysis is executed through sophisticated pipelines that provide calibrated values for key stellar parameters, including effective temperature and metallicity. The precise determination of radial velocities and elemental abundances significantly enhances our capacity to investigate the dynamic and chemical structure of the Galaxy, pursuing objectives in Galactic archaeology.

Challenges and Considerations

A notable challenge in APOGEE's data analysis is the calibration of stellar parameters, particularly with variations such as systematic offsets when compared to high-resolution optical benchmarks. While the data quality is calibrated to ameliorate such discrepancies, it underscores the complex nature of integrating infrared spectroscopic data into broader galactic models.

The BOSS spectroscopic analysis presented some issues pertaining to CCD limitations, such as transient hot columns and astrometric anomalies, which are flagged for further refinement in upcoming data releases.

Future Directions

This data release is an integral step in preparing for subsequent data releases, namely DR11 and DR12, which will further enhance the breadth and utility of the SDSS dataset. With SDSS-IV on the horizon, the integration of the BOSS and APOGEE approaches with enhanced observational capacity—including a southern hemisphere component—unfolds the potential for an extensive survey footprint.

Conclusion

The SDSS DR10 represents a pivotal point in enhancing matter cosmology observations, stellar population studies, and the detailed analysis of the galactic structure. As future data releases expand upon this foundation, the combination of extensive sky coverage and detailed spectroscopic insights will continue to contribute significantly to the fields of astrophysics and cosmology.