The Science Legacy of the
Sloan Digital Sky Survey
by Simon Mitton
Physics
Top Ten Papers
Rank
Papers
Cites
Jan-Feb 09
Rank
Nov-Dec 08
1
D.N. Spergel, et al.,
"Three-year Wilkinson Microwave
Anisotropy Probe (WMAP)
observations: Implications for
cosmology," Astrophys. J. Suppl.
Ser., 170(2): 377-408, June 2007.
[13 U.S. and Canadian institutions]
*178TD
101
1
2
X.H. Chen, et al.,
"Superconductivity at 43K in SmFeAs
O1-xFx,"
Nature, 453(7196): 761-2, 5
June 2008. [U. Sci. & Tech., Hefei,
China] *308UK
54
2
3
J.Y. Kim, et al., "Efficient
tandem polymer solar cells fabricated
by all-solution processing,"
Science, 317(5835): 222-5, 13
July 2007. [U. Calif., Santa Barbara;
Gwangju Inst. Sci. Tech., Korea] *189DC
42
4
4
M.Y Han, et al., "Energy
band-gap engineering of graphene
nanoribbons," Phys. Rev.
Lett., 98(20): no. 206805, 18 May
2007. [Columbia U., New York, NY]
*169WY
38
8
5
Z.A. Ren, et al.,
"Superconductivity at 55 K in
iron-based F-doped layered quaternary
compound
Sm[O1-xFx]FeAs,"
Chinese Phys. Lett., 25(6):
2215-6, June 2008. [Chinese Acad. Sci,
Beijing] *306MN
37
3
6
J.K. Adelman-McCarthy, et al.,
"The Sixth Data Release of the Sloan
Digital Sky Survey," Astrophys. J.
Suppl. Ser., 175(2): 297-313,
April 2008. [84 institutions worldwide]
*327WN
34
†
7
J. Dong, et al., "Competing
orders and spin-density-wave
instability in
La(O1-xFx)FeAs,"
EPL-Europhys. Lett., 83(2):
no. 27006, July 2008. [Beijing Natl.
Lab. Condensed Matter Phys., Chinese
Acad. Sci.] *345TZ
29
0
8
J.K. Adelman-McCarthy, et al.,
"The Fifth Data Release of the Sloan
Digital Sky Survey," Astrophys. J.
Suppl. Ser., 172(2): 634-44,
October 2007. [73 institutions
worldwide] *212HY
28
†
9
G. Hinshaw, et al.,
"Three-year Wilkinson Microwave
Anisotropy Probe (WMAP)
observations: Temperature analysis,"
Astrophys. J. Suppl. Ser.,
170(2): 288-334, June 2007. [14 U.S.
and Canadian institutions] *178TD
26
†
10
Z.A. Ren, et al.,
"Superconductivity at 52 K in iron
based F doped layered quaternary
compound
Pr[O1-x
Fx]FeAs,"
<MI>Mater. Res.
Innovat.<D>, 12(3): 105-6,
September 2008. [Chinese Acad. Sci.,
Beijing] *362RG
The Hot Papers in Physics for this period include the fifth (paper
#8) and sixth (#6) releases of data from the Sloan Digital Sky Survey
(SDSS). The release of the seventh and final SDSS dataset, published in May
2009 (Astrophys. J. Supp. Ser., 182[2]: 545-58), marks the
completion of the original goals of the SDSS, launched a decade ago. Now is
an appropriate time to review the science achievements of this remarkable
project. All of the survey’s data-release papers have featured as
highly cited papers in Science Watch, because the data have
supported a large number of research projects in the global community of
astronomers.
The 2.5-m Sloan telescope is a comprehensive imaging and spectroscopic
instrument at Apache Point Observatory in southern New Mexico. The original
purpose of the survey was to map the structure of the
universe and to understand how that structure
arose. The most distant objects in the SDSS are approximately 13
billion light years away. SDSS has mapped the three-dimensional
structure of a large slice of the universe, spanning the time and
distance from the local universe to the early universe. Its 3D map
shows how the structure of the universe has evolved.
The fundamental data of SDSS is freely available online to any user; #6 and
#8 (and their predecessors) give the technical background required to
analyze the data. Paper #6 proudly announces that the survey includes 1.27
x 106 spectra of stars, galaxies, and quasars. The stellar
spectroscopy is far more detailed than previously, and the release includes
detailed estimates of stellar temperatures and metallicities (a measure of
chemical make-up).
SDSS has imaged 12,000 square degrees (over 1/4 of the sky) in five
wavebands, and performed spectroscopy on 106 galaxies and
105 quasars to create the 3D structural map. In addition, SDSS
has explored the structure and kinematics of the Milky Way galaxy and
discovered more than 500 Type Ia supernovae, observations of which have
transformed supernova cosmology.
In terms of its science legacy, SDSS has outperformed any previous surveys
by a huge margin. Its discovery of the most distant quasars probe the
transition phase of the universe, in which protons and electrons recombined
to form neutral hydrogen. Quasars seen at the epoch when the universe was
10% to 25% of its present age cluster more tightly than in the nearby
universe, which suggests they are surrounded by concentrations of
dark matter, with an underlying distribution that
can be measured with high precision. The high-quality images, distances,
masses, and ages of galaxies have provided powerful insights into galaxy
formation. SDSS is a potent tool for exploiting weak gravitational
lensing, which has revealed the dark matter distribution in galactic
haloes.
Locally, SDSS has discovered many dwarf companions to the Milky Way: star
mapping has revealed nine new satellites of our own galaxies, as well as
two new dwarfs belonging to the Andromeda galaxy. These discoveries are
important because theories of galaxy formation in a dark-matter universe
had predicted that giant galaxies like the Milky Way should have numerous
companions.
Up in the outer halo of the Milky Way, SDSS spied speeding stars close to
or even exceeding escape velocity. Violent gravitation encounters with the
supermassive black hole at the heart of the Milky Way have flung
these escapees outwards by a slingshot effect. A new stellar population
has come to light: sub-stellar objects, or "failed" stars that are too
cool in their cores to ignite nuclear reactions.
And in our own backyard SDSS has provided new facts about the solar system.
That’s because moving objects, primarily asteroids, leave a trail in
the images. SDSS hugely increased the number of known asteroids, and
provided colors for them. As a result, planetary science now has better
data on the size distribution of asteroids.
The SDSS telescope has entered on the third operational mission, SDSS-III.
There are four goals: to increase the number of faint stars in the distant
halo by a factor of 2.5; to perform spectroscopy on 1.5 x 106
red galaxies; to monitor any changes in the line of sight velocities of
11,000 stars as a means of detecting exoplanets; and to carry out
spectroscopy on 105 giant stars for chemical studies of the
Milky Way. The SDSS team expects data releases to continue until
2014.
Dr. Simon Mitton is a Fellow of St. Edmund’s College,
Cambridge, U.K.
KEYWORDS: SLOAN DIGITAL SKY SURVEY, SDSS, APACHE POINT OBSERVATORY, STELLAR
SPECTROSCOPY, FAILED STARS, QUASARS, MILKY WAY, GRAVITATIONAL LENSING.