Andrew Yee
March 9th 06, 04:08 PM
News Service
Cornell University
Ithaca, New York
Media Contact:
Lauren Gold, (607) 255-9736
March 8, 2006
New Arecibo receiver triggers quiet revolution that could discover 20,000
galaxies and 1,000 pulsars
By Lauren Gold
When the Arecibo L-Band Feed Array (ALFA) was installed on a misty April
morning two years ago, it promised to bring phenomenal new sensitivity to
the Arecibo Observatory.
Now, well into an ambitious series of comprehensive sky surveys using the
receiver, astronomers say ALFA is delivering spectacularly: both by
fulfilling the potential of the observatory's 1990s Gregorian upgrade and
ultimately by changing business as usual for researchers worldwide.
The ALFA system of detectors and associated electronics, jointly built by
National Astronomy and Ionosphere Center (NAIC) and Australian engineers,
is slightly bigger than a washing machine and has seven feeds -- making it
essentially a giant seven-pixel radio camera that allows researchers to
image large swaths of sky and search for such time-variable phenomena as
pulsars seven times more efficiently than in the past.
In just two years, ALFA has provided a wealth of new data, from comets
passing near the Earth and giant clouds of gas in our own galaxy, to some
of the most distant objects ever detected. It's a quiet revolution -- but
Jim Cordes, Cornell professor of astronomy and one of the principal
scientists behind ALFA's conception, says the improvements are
unparalleled.
"You could very well say it's a new phase for Arecibo," Cordes said.
"We're doing things that are pretty unique to what Arecibo can do --
playing on its strengths."
Cordes uses ALFA to find and observe pulsars, massive rapidly spinning
neutron stars that are ejected in stellar explosions, or supernovae. The
pulsar search could lead to a deeper understanding of Einstein's theory of
relativity.
"ALFA is going to discover probably 1,000 new pulsars that we haven't seen
yet," said former ALFA project manager Stephen Torchinsky. "The
expectation is that we're going to find some exotic objects. We could use
these systems to test the limits of the theory of relativity -- and at the
most extreme cases, to find gravitational waves."
ALFA science is divided into three overarching surveys: the pulsar survey,
a survey for sources of neutral hydrogen in the Milky Way and an
extragalactic survey. In terms of sheer quantity of data, it is providing
an abundance, spurring scientists to come up with new ways of sorting
through and managing the constant torrent of information.
"It's like you have seven fire hoses of data coming at you," Cordes said.
"It's really a challenge to deal with."
That challenge is being met in part by scientists at the Cornell Theory
Center, who are creating a computer system to manage vast amounts of data
from such surveys as the Arecibo Legacy Fast ALFA survey (ALFALFA), a
broad extragalactic search for faint cosmic radio signals from hydrogen
clouds.
ALFALFA is expected to detect some 20,000 galaxies from as far away as 750
million light years over the next six years. Astronomers hope the survey
will lead to the discovery of dark galaxies: never-before-observed
galaxies composed largely of dark matter and hydrogen gas that could offer
valuable information about the way galaxies form and evolve.
"Without ALFA, a project like this could not have been done," said
Riccardo Giovanelli, Cornell professor of astronomy and ALFALFA project
leader. "It would have been too demanding on a few people."
But part of ALFA's value, say its users, is in the collaborative style of
research it invites. In the receiver's two years of operation, the number
of annual users at Arecibo has jumped by nearly 50 percent -- to 335 users
in 2005 from 215 users in 2003. (Other factors have been involved, but
ALFA is credited with the majority of the increase.) "We're bringing new
users to Arecibo," said Martha Haynes, Goldwin Smith Professor of
Astronomy at Cornell and a member of the ALFALFA team. Many are
undergraduates -- evidence that the receiver is energizing the next
generation of astronomers.
Torchinsky, however, worries that ALFA's success could overpower other
research. "It's changed the culture a lot," he said, "but I don't think
it's entirely for the best. ALFA has begun to dominate astronomy work
being done at Arecibo ... making it more difficult for individual
proposals in general. Some good ideas have not been developed because of
this."
But others say the increase in users -- especially young ones -- makes it
clear that the change is a good one. And they add that the receiver's
science will benefit researchers well beyond those currently involved.
"The goal of the major surveys is to produce archival databases that are
accessible to all researchers and will be valuable resources for many
decades to come," said Robert Brown, director of the Cornell-based NAIC,
which manages the Arecibo Observatory for the National Science Foundation.
It's part of a welcome trend, said Haynes.
"ALFA and the big surveys have changed the way science is being done at
Arecibo," she said. "It's exciting. It's challenging. This is the modern
way of doing astronomy."
Related Information:
* National Astronomy and Ionosphere Center
http://www.naic.edu/
* Arecibo ALFA home
http://alfa.naic.edu/
* ALFALFA
http://egg.astro.cornell.edu/alfalfa/epo/index.php
IMAGE CAPTION:
[http://www.news.cornell.edu/stories/March06/ALFA_students.jpg (77KB)]
Cornell astronomy graduate student Sabrina Stierwalt "uncovers" ALFA with
telescope operator William Torres, right, and Colgate senior Brian Walsh,
left, in January 2006. (Tom Balonek)
Cornell University
Ithaca, New York
Media Contact:
Lauren Gold, (607) 255-9736
March 8, 2006
New Arecibo receiver triggers quiet revolution that could discover 20,000
galaxies and 1,000 pulsars
By Lauren Gold
When the Arecibo L-Band Feed Array (ALFA) was installed on a misty April
morning two years ago, it promised to bring phenomenal new sensitivity to
the Arecibo Observatory.
Now, well into an ambitious series of comprehensive sky surveys using the
receiver, astronomers say ALFA is delivering spectacularly: both by
fulfilling the potential of the observatory's 1990s Gregorian upgrade and
ultimately by changing business as usual for researchers worldwide.
The ALFA system of detectors and associated electronics, jointly built by
National Astronomy and Ionosphere Center (NAIC) and Australian engineers,
is slightly bigger than a washing machine and has seven feeds -- making it
essentially a giant seven-pixel radio camera that allows researchers to
image large swaths of sky and search for such time-variable phenomena as
pulsars seven times more efficiently than in the past.
In just two years, ALFA has provided a wealth of new data, from comets
passing near the Earth and giant clouds of gas in our own galaxy, to some
of the most distant objects ever detected. It's a quiet revolution -- but
Jim Cordes, Cornell professor of astronomy and one of the principal
scientists behind ALFA's conception, says the improvements are
unparalleled.
"You could very well say it's a new phase for Arecibo," Cordes said.
"We're doing things that are pretty unique to what Arecibo can do --
playing on its strengths."
Cordes uses ALFA to find and observe pulsars, massive rapidly spinning
neutron stars that are ejected in stellar explosions, or supernovae. The
pulsar search could lead to a deeper understanding of Einstein's theory of
relativity.
"ALFA is going to discover probably 1,000 new pulsars that we haven't seen
yet," said former ALFA project manager Stephen Torchinsky. "The
expectation is that we're going to find some exotic objects. We could use
these systems to test the limits of the theory of relativity -- and at the
most extreme cases, to find gravitational waves."
ALFA science is divided into three overarching surveys: the pulsar survey,
a survey for sources of neutral hydrogen in the Milky Way and an
extragalactic survey. In terms of sheer quantity of data, it is providing
an abundance, spurring scientists to come up with new ways of sorting
through and managing the constant torrent of information.
"It's like you have seven fire hoses of data coming at you," Cordes said.
"It's really a challenge to deal with."
That challenge is being met in part by scientists at the Cornell Theory
Center, who are creating a computer system to manage vast amounts of data
from such surveys as the Arecibo Legacy Fast ALFA survey (ALFALFA), a
broad extragalactic search for faint cosmic radio signals from hydrogen
clouds.
ALFALFA is expected to detect some 20,000 galaxies from as far away as 750
million light years over the next six years. Astronomers hope the survey
will lead to the discovery of dark galaxies: never-before-observed
galaxies composed largely of dark matter and hydrogen gas that could offer
valuable information about the way galaxies form and evolve.
"Without ALFA, a project like this could not have been done," said
Riccardo Giovanelli, Cornell professor of astronomy and ALFALFA project
leader. "It would have been too demanding on a few people."
But part of ALFA's value, say its users, is in the collaborative style of
research it invites. In the receiver's two years of operation, the number
of annual users at Arecibo has jumped by nearly 50 percent -- to 335 users
in 2005 from 215 users in 2003. (Other factors have been involved, but
ALFA is credited with the majority of the increase.) "We're bringing new
users to Arecibo," said Martha Haynes, Goldwin Smith Professor of
Astronomy at Cornell and a member of the ALFALFA team. Many are
undergraduates -- evidence that the receiver is energizing the next
generation of astronomers.
Torchinsky, however, worries that ALFA's success could overpower other
research. "It's changed the culture a lot," he said, "but I don't think
it's entirely for the best. ALFA has begun to dominate astronomy work
being done at Arecibo ... making it more difficult for individual
proposals in general. Some good ideas have not been developed because of
this."
But others say the increase in users -- especially young ones -- makes it
clear that the change is a good one. And they add that the receiver's
science will benefit researchers well beyond those currently involved.
"The goal of the major surveys is to produce archival databases that are
accessible to all researchers and will be valuable resources for many
decades to come," said Robert Brown, director of the Cornell-based NAIC,
which manages the Arecibo Observatory for the National Science Foundation.
It's part of a welcome trend, said Haynes.
"ALFA and the big surveys have changed the way science is being done at
Arecibo," she said. "It's exciting. It's challenging. This is the modern
way of doing astronomy."
Related Information:
* National Astronomy and Ionosphere Center
http://www.naic.edu/
* Arecibo ALFA home
http://alfa.naic.edu/
* ALFALFA
http://egg.astro.cornell.edu/alfalfa/epo/index.php
IMAGE CAPTION:
[http://www.news.cornell.edu/stories/March06/ALFA_students.jpg (77KB)]
Cornell astronomy graduate student Sabrina Stierwalt "uncovers" ALFA with
telescope operator William Torres, right, and Colgate senior Brian Walsh,
left, in January 2006. (Tom Balonek)