Telescope Reviews: Galaxy Zoo Press Release

Press release concerning the work of Dr. Pamela L. Gay

EMBARGOED UNTIL:
10:30 a.m. PDT (1:30 p.m. EDT)
Tuesday, June 9, 2009

Contacts:
Dr. Pamela L. Gay
pgay@siue.edu
+1 857-204-6392

Dr. Chris Lintott
cjl@astro.ox.ac.uk
+44 (0)78-0816-7288

Prof. Raul Jimenez
raul@ieec.uab.es
+34 935-814-365

VOLUNTEERS PUT A NEW SPIN ON GALAXY ROTATION

The International Year of Astronomy has brought success to Galaxy Zoo
(www.galaxyzoo.org), an innovative online collaboration between
astronomers and more than 200,000 members of the public. During IYA’s
“100 Hours of Astronomy,” April 2-5 2009, Galaxy Zoo users provided
more than 2.5 million classifications of galaxies drawn from the Sloan
Digital Sky Survey, smashing the 1-million-click target the team had
set. In all, Zoo visitors have contributed more than 32 million
classifications since the launch of Galaxy Zoo 2 on February 17, 2009.

Galaxy Zoo 2 builds on the success of the original Galaxy Zoo, which
asked users to sort galaxies into one of six categories according to
their shape. Zoo 2 asks for more detailed classifications of 250,000
of the best and brightest of the Sloan galaxies, recording information
on galaxy bars, spiral arm properties, and more. Between Galaxy Zoo 1
and 2, more than 100 million classifications have been recorded -- the
equivalent of a single PhD student working for almost 20 years without
sleep or coffee breaks. IYA New Media chair Pamela Gay said, “Without
the help and hard work of the Galaxy Zoo volunteers throughout the
International Year of Astronomy, our understanding of galaxies
wouldn’t be as rich and as colorful.”

As of April 2009, the combined efforts of Galaxy Zoo and Galaxy Zoo 2
had produced over 100 million galaxy classifications leading to new
understandings in galaxy evolution, the isotropy of the universe,
galaxy mergers, and more.

The latest Galaxy Zoo science result[1] shows that spiral galaxies
which share a neighborhood (within a region 65 million light-years
across) are likely to rotate in the same direction -- but only if they
formed the vast majority of their stars more than 10 billion years
ago. The work is further confirmation that spectacular mergers between
galaxies are the driving force behind more recent galactic evolution,
disrupting the galaxies’ alignment while triggering star formation.
Project lead Raul Jimenez (ICREA and the Institute of Space Sciences,
Spain) said, “It is very exciting to see this result from Galaxy Zoo
-- now it is time to go back to theory and simulations and understand
better what it all means!”

An earlier Galaxy Zoo paper (Slosar et al.) provided support for the
theory that spiral galaxies acquire their angular momentum from the
large-scale structure from which they form. As nearby galaxies will
have formed in the same environment, they would be expected to share
-- on average -- a direction. Later interactions and mergers which are
known to trigger star formation may also have randomized the spin
directions of the participating galaxies, producing the correlation
between star formation and spins seen in the latest paper. No physical
parameter other than star formation history is correlated with the
galaxies.

Mergers have long been believed to contribute to the observed
evolution of galaxy populations; a head-on collision between two
spirals, for example, will often produce an elliptical. This new
result suggests that mergers are also an important influence on spiral
galaxies themselves. In two companion papers,[2] the Galaxy Zoo team
examine the properties of the largest merger catalogue to date,
consisting of 3000 systems selected from the almost one million
galaxies in SDSS.

Other results from Galaxy Zoo have investigated the role of blue
elliptical galaxies and red spirals in galaxy evolution and followed
up unusual objects like Hanny’s Voorwerp. As project principal
investigator Chris Lintott remarked, “With the Zoo 2 target of 40
million classifications in sight, participants in this IYA project
will soon truly have made the Universe theirs to discover.”

# # #

This work has been made possible by the more than 100,000 volunteers
in the original Galaxy Zoo project. Their individual contributions are
acknowledged at http://www.galaxyzoo.org/Volunteers.aspx.

Galaxy Zoo is a proud part of the International Year of Astronomy.
Learn more about Galaxy Zoo at http://www.galaxyzoo.org, and explore
the International Year of Astronomy at http://www.astronomy2009.us and
http://www.astronomy2009.org.

Funding for the SDSS and SDSS-II has been provided by the Alfred P.
Sloan Foundation, the Participating Institutions, the National Science
Foundation, the U.S. Department of Energy, the National Aeronautics
and Space Administration, the Japanese Monbukagakusho, the Max Planck
Society, and the Higher Education Funding Council for England. The
SDSS Web Site is http://www.sdss.org/.

The SDSS is managed by the Astrophysical Research Consortium for the
Participating Institutions. The Participating Institutions are the
American Museum of Natural History, Astrophysical Institute Potsdam,
University of Basel, University of Cambridge, Case Western Reserve
University, University of Chicago, Drexel University, Fermilab, the
Institute for Advanced Study, the Japan Participation Group, Johns
Hopkins University, the Joint Institute for Nuclear Astrophysics, the
Kavli Institute for Particle Astrophysics and Cosmology, the Korean
Scientist Group, the Chinese Academy of Sciences (LAMOST), Los Alamos
National Laboratory, the Max-Planck-Institute for Astronomy (MPIA),
the Max-Planck-Institute for Astrophysics (MPA), New Mexico State
University, Ohio State University, University of Pittsburgh,
University of Portsmouth, Princeton University, the United States
Naval Observatory, and the University of Washington.

Notes:
[1] http://lanl.arxiv.org/abs/0906.0994
[2] http://lanl.arxiv.org/abs/0903.5057,

http://lanl.arxiv.org/abs/0903.4937