Reinvigorated Hubble Space Telescope Reveals
Most Distant Galaxies Yet
Using the recently updated Hubble Space Telescope (HST) two teams
of UK astronomers have identified galaxies which are likely to be
the
most distant yet seen. The UK teams, one led by Andrew Bunker and
Stephen
Wilkins at the University of Oxford and the other by Ross McLure and
Jim
Dunlop at the University
of Edinburgh, analysed infrared images from the new Wide Field
Camera
3 (WFC3) instrument on HST, installed during the most recent
Space Shuttle servicing mission in May 2009. Infrared light is light
invisible to the
human eye, with wavelengths about twice as long as visible light -
beyond the red.
"The expansion of the Universe causes the light from very
distant
galaxies to appear more red, so having a new camera on Hubble which
is
very sensitive in the infrared means we can identify galaxies at
much
greater distances than previously possible" explained Stephen
Wilkins,
a postdoctoral researcher in astrophysics at Oxford University.
In a series of papers, to appear in the Monthly Notices of the Royal
Astronomical
Society, the UK teams present their analysis of the most sensitive
images of the Universe yet taken in the infrared.
"The unique infrared sensitivity of Wide Field Camera 3 means
that
these are the best images yet for providing detailed information
about the first galaxies as they formed in the early Universe",
explained Dr Ross McLure (from the Institute for Astronomy in
Edinburgh).
The new images from Hubble include the region of sky known as the
Hubble Ultra Deep Field,
which Bunker and colleagues were the first to analyse 5 years ago
using visible light images taken with Hubble's Advanced Camera for
Surveys (ACS).
"Hubble has now re-visited the Ultra Deep Field which we first
studied
5 years ago, taking infrared images which are more sensitive than
anything obtained before. We can now look even further back in time,
identifying galaxies when the Universe was only 5 percent of its
current age - within 1 billion years of the Big Bang" said Dr
Daniel Stark,
a postdoctoral researcher at the Institute of Astronomy in Cambridge
who was involved in the work of both UK teams.
As well as identifying potentially the most distant objects yet,
these
new HST observations present an intriguing puzzle. "We know the
gas
between galaxies in the Universe was ionized (or fried) early
in history, but the total light from these new galaxies may not
be sufficient to achieve this." said Andrew Bunker, a
researcher at
the University of Oxford.
"These new observations from HST are likely to be the most
sensitive
images Hubble will ever take, but the very distant galaxies we have
now discovered will be studied in detail by Hubble's successor, the
James Webb Space Telescope, which will be launched in 2014."
said
Professor Jim Dunlop at the University of Edinburgh.
The Hubble Ultra Deep Field showing the location of a
potentially very distant galaxy (marked by crosshairs). Credit: Ross McLure (Edinburgh)
A portion of the Hubble Ultra Deep Field showing the location of a
potentially very distant galaxy (marked by crosshairs). Credit: Andrew Bunker,
Stephen Wilkins (Oxford)
The Hubble Space Telescope. Courtesy of NASA. (http://hubblesite.org/gallery/spacecraft/28/web_print)
Installation of Wide Field Camera 3 by astronauts as part of
servicing mission 4. Courtesy of NASA. (http://hubblesite.org/gallery/spacecraft/27/web_print)
References:
[1] R.J.
McLure, J.S. Dunlop, M. Cirasuolo, A.M. Koekemoer, E. Sabbi, D.P. Stark, T.A.
Targett, R.S. Ellis, Accepted in the Monthly Notices of the
Royal Astronomy Society,
http://arxiv.org/abs/0909.2437
[2] Stephen M. Wilkins, Andrew J. Bunker, Richard S. Ellis, Daniel Stark, Elizabeth R. Stanway, Kuenley Chiu, Silvio Lorenzoni, Matt J. Jarvis, Accepted in the Monthly Notices of the Royal Astronomy Society, http://arxiv.org/abs/0910.1098
[3] Bunker, Andrew; Wilkins, Stephen; Ellis, Richard; Stark, Daniel;
Lorenzoni, Silvio; Chiu, Kuenley; Lacy, Mark; Jarvis, Matt; Hickey, Samantha, Submitted
to the Monthly Notices of the Royal Astronomy Society, http://arxiv.org/abs/0909.2255
Dr Andrew Bunker
Oxford Astrophysics
Department of Physics
Denys Wilkinson Building
Keble Road
Oxford, OX1 3RH
tel: +44 (0)1865
273303
email: a.bunker1@physics.ox.ac.uk
Mr Stephen Wilkins
Oxford Astrophysics
Department of Physics
Denys Wilkinson Building
Keble Road
Oxford, OX1 3RH
tel: +44 (0)1865
273303
email: stephen.wilkins@astro.ox.ac.uk
Dr Ross McLure
Institute for Astronomy
University of Edinburgh
Royal Observatory
Blackford Hill
Edinburgh, EH9 3HJ
tel: +44 (0) 131 668
8100
email: rjm@roe.ac.uk
Prof Jim Dunlop
Institute for Astronomy
University of Edinburgh
Royal Observatory
Blackford Hill
Edinburgh, EH9 3HJ
tel: +44 (0) 131 668
8100
email: jsd@roe.ac.uk
Dr Daniel Stark
Institute of Astronomy
University of Cambridge
Madingley Road
Cambridge CB3 0HA
United Kingdom
tel: +44 (0)1223
337548
email: dps@ast.cam.ac.uk
Prof Richard Ellis FRS CBE
Caltech Astronomy
249-17 Astronomy
Caltech
Pasadena
CA 91125 USA
tel: +1-626-395-4970
e-mail: rse@astro.caltech.edu