Table of Contents
- eBOSS Data Products — A description of the eBOSS data products hosted at MAST.
eBOSS Overview
Survey Summary
The Extended Baryon Oscillation Spectroscopic Survey is a cosmological spectroscopic survey of millions of galaxies and quasars probing the large-scale structure of the Universe. eBOSS is an extension of the SDSS-III BOSS survey, which ran from 2008-2014. eBOSS continued collecting data between 2014-2020 as part of the SDSS-IV project. The final data release of eBOSS (DR17) includes reductions of all observations taken by eBOSS in SDSS-IV as well as BOSS in SDSS-III. All observations have been processed with the same eBOSS Data Reduction Pipeline. Figure 1 shows a graphical overview of the eBOSS survey, demonstrating how high-redshift quasars are bused to map the large scale structure of the Universe.
Figure 1 - eBOSS mapped the distribution of galaxies and quasars from when the Universe was 3 to 8 billion years old, a critical time when dark energy started to affect the expansion of the Universe. At higher redshifts, during a time when the Universe was matter-dominated, eBOSS uses the Lyman-alpha forest to map out the matter distribution. Image Credit: Dana Berry / SkyWorks Digital Inc. and the SDSS collaboration.
Telescopes & Instrumentation
eBOSS data were obtained at the Apache Point Observatory in New Mexico using the SDSS-2.5m telescope (Gunn et al. 2006), using the BOSS spectrograph. The BOSS spectrograph is a ``1000 fiber-fed spectrograph with wavelength coverage between 360 nm to 1040 nm and resolution (λ/δλ) of roughly 2000. SDSS observed using plug plates, aluminum plates with holes drilled corresponding to individual astronomical objects or random blank areas of sky. A plug plate covers a 3-degree diameter circle on the sky, with each fiber having a 2-arcsec diameter. Each of the 1000 fibers were plugged into individual holes for each plate for an observation, allowing for 1000 spectra to be taken simultaneously. A picture of a plate used in the eBOSS survey is shown in Figure 2.
Figure 2 - A picture of an aluminum plug plate used for the SDSS-III BOSS survey. Each plate is a 30-inch diameter aluminum disc with 1000 holes drilled in it, each corresponding to a different target for observation. Various annotations are drawn on the plate to help observers plug in the optical fibers. Image Credit: the SDSS collaboration.
Data Products and Access
The eBOSS data products are available for download through several MAST interfaces, including the MAST Portal and programmatically in Python through astroquery.mast. For information on how to access and download eBOSS data through MAST, please refer to the Data Access page.
MAST has archived the high-level "science ready" data products from the eBOSS survey. The eBOSS Data Products page contains details on which files are available at MAST, which include the summary catalog and the 1d extracted spectra from the eBOSS Data Reduction Pipeline.
Caveats:
- the original SDSS "spec-lite" files, e.g.
spec-10241-58157-0004.fitshave been renamed at MAST tospec-lite-10241-58157-0004.fitsto differentiate them from the "full" spec files.
Citations and Acknowledgements
Refer to the SDSS Surveys page for instructions on how to cite this document and acknowledge the use of data obtained from MAST in publications.
For other relevant eBOSS citations, please refer to the relevant section of the SDSS Technical Papers list. These include:
- SDSS DR-17 Overview: Abdurro’uf et al. 2022
- SDSS DR-16 Overview: Ahumada et al. 2020
- eBOSS Survey Overview: Dawson et al. 2016
SDSS 2.5-meter Telescope description: Gunn et al. 2006
- eBOSS ELG Target Selection: Raichoor et al. 2017
- eBOSS Quasar Target Selection: Myers et al. 2015
- eBOSS LRG Target Selection: Prakash et al. 2016