From SDSS: “SDSS Fourteenth Data Release”

SDSS Science blog bloc

Science Blog from the SDSS

July 31, 2017
Rita Tojeiro
This post was written by Anne-Marie Weijmans, the SDSS Data Release Coordinator.

It’s the last day in July, and that means that it’s time again for a Sloan Digital Sky Survey (SDSS) data release! This year, we are very happy to announce our fourteenth public data release, DR14.

Making data publicly available is an important aspect of SDSS, as it allows SDSS data to be used world-wide by anyone with an internet connection. For more than a decade, SDSS data has been used by astronomers for their science, by teachers in their classrooms[1], by students for their school projects, and by the general public to learn more about the Universe. In order to have this broad impact, we work hard to not only make our data available, but to also ensure that it is accessible. All our data is thoroughly documented, and we have various tools, tutorials and examples to assist anyone interested in using our data — from professional astronomers to high school students. Just go to the SDSS data access website to find out how you can work with the SDSS data!

1
All the SDSS data are stored at the servers of the Center for High Performance Computing (CHPC), at the University of Utah. This particular server holds all the SDSS data releases, including DR14. Just DR14 alone is already a whopping 156 TeraBytes (TB = 1000 Gigabyte = 1012 bytes): that is more than 33,800 DVDs worth of data! Image credit: Adam Bolton

So, what is available in DR14?

APOGEE-2, or the APO Galaxy Evolution Experiment-2 is very proud to announce its first public data release! APOGEE-2 studies the structure of the Milky Way by taking infra-red spectra of stars, to learn more about how the Milky Way formed and evolved over time. You can explore these spectra using our webapp and find stellar parameters and chemical properties in the APOGEE-2 data release.
eBOSS, short for extended Baryon Oscillation Spectroscopic Survey, is also celebrating its first public data release! eBOSS is mapping the structure of the Universe, by taking optical spectra of distant galaxies and quasars. These spectra provide distance measurements to galaxies, quasars, and intervening gas, all of which enable eBOSS to make a 3D map of the Universe, and learn more about how galaxies cluster in space. Ultimately, eBOSS aims to precisely measure the expansion rate of the Universe, and reveal more about the nature of the mysterious Dark Energy that accelerates this expansion. The eBOSS spectra are also available in our webapp.

MaNGA or Mapping Nearby Galaxies at Apache Point Observatory already released its first data last year, but they’re back with even more data cubes, 2,812 in total! MaNGA uses integral-field spectroscopy to map the properties of galaxies, and find out more about how different galaxies form and evolve. The MaNGA team has prepared a very handy set of tutorials to explain the data cube format, so that anyone can make use of the wealth of information hidden in these galaxy integral-field spectra.

Finally, we’re also very excited to share our new Image Policy with you! We have updated our image license to a Creative Commons Attribution license (CC-BY), which means that any image on our website may now be downloaded, linked to, or otherwise used for any purpose, provided that the image credits are given.

We hope you’ll have fun with all the spectra, catalogs, and tools included in our Fourteenth Data Release, and that they will help you with your science, outreach, teaching, school projects, and anything else!

Anne-Marie Weijmans

SDSS Data Release Coordinator

University of St Andrews

See the full article here .

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After nearly a decade of design and construction, the Sloan Digital Sky Survey saw first light on its giant mosaic camera in 1998 and entered routine operations in 2000. While the collaboration and scope of the SDSS have changed over the years, many of its key principles have stayed fixed: the use of highly efficient instruments and software to enable astronomical surveys of unprecedented scientific reach, a commitment to creating high quality public data sets, and investigations that draw on the full range of expertise in a large international collaboration. The generous support of the Alfred P. Sloan Foundation has been crucial in all phases of the SDSS, alongside support from the Participating Institutions and national funding agencies in the U.S. and other countries.

The Sloan Digital Sky Survey has created the most detailed three-dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects.

In its first five years of operations, the SDSS carried out deep multi-color imaging over 8000 square degrees and measured spectra of more than 700,000 celestial objects. With an ever-growing collaboration, SDSS-II (2005-2008) completed the original survey goals of imaging half the northern sky and mapping the 3-dimensional clustering of one million galaxies and 100,000 quasars. SDSS-II carried out two additional surveys: the Supernova Survey, which discovered and monitored hundreds of supernovae to measure the expansion history of the universe, and the Sloan Extension for Galactic Understanding and Exploration (SEGUE), which extended SDSS imaging towards the plane of the Galaxy and mapped the motions and composition of more than a quarter million Milky Way stars.

SDSS-III (2008-2014) undertook a major upgrade of the venerable SDSS spectrographs and added two powerful new instruments to execute an interweaved set of four surveys, mapping the clustering of galaxies and intergalactic gas in the distant universe (BOSS), the dynamics and chemical evolution of the Milky Way (SEGUE-2 and APOGEE), and the population of extra-solar giant planets (MARVELS).

The latest generation of the SDSS (SDSS-IV, 2014-2020) is extending precision cosmological measurements to a critical early phase of cosmic history (eBOSS), expanding its revolutionary infrared spectroscopic survey of the Galaxy in the northern and southern hemispheres (APOGEE-2), and for the first time using the Sloan spectrographs to make spatially resolved maps of individual galaxies (MaNGA).

This is the “Science blog” of the SDSS. Here you’ll find short descriptions of interesting scientific research and discoveries from the SDSS. We’ll also update on activities of the collaboration in public engagement and other arenas. We’d love to see your comments and questions about what you read here!

You can explore more on the SDSS Website.

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