Deep image of the galaxy cluster Abell 2744 obtained with the Hubble
Space Telescope. The zoomed image shows the region around the galaxy
Abell2744_Y1, one of the most distant galaxies in the Universe. Credit: NASA, ESA, and J. Lotz, M. Mountain, A. Koekemoer, and the HFF Team (STScI); Nicolas Laporte et al. (IAC); Gabriel Pérez – SMM (IAC)
Researchers from the Instituto de Astrofísica de Canarias and La
Laguna University lead the international team that has analyzed the
images
An international team led by astronomers from the Instituto de
Astrofísica de Canarias (IAC) and La Laguna University (ULL) has just
completed the first analysis of the observations of the Abell 2744
cluster of galaxies, a coordinated program of the Hubble and Spitzer
Space Telescopes. The first result of this study is the discovery of one
of the most distant galaxies known to date, which clearly shows the
potential of the HST Frontier Fields project. These results will be
published in the scientific journal Astronomy and Astrophysics Letters.
This
work involves also researchers from France (Institut de Recherche en
Astrophysique et Planétologie de Toulouse and Centre de Recherche
Astrophysique de Lyon), Switzerland (Geneva University and Ecole
Polytechnique Federal de Lausanne), and United States (University of
Arizona).
Thanks to the high data quality of the Hubble (in the
optical and near-infrared) and Spitzer (infrared) data, these
astrophysicists have determined the properties of this young galaxy with
a better precision than previous studies of other samples at similar
cosmic epochs. This galaxy, named Abell2744_Y1, is about 30 times
smaller than our Galaxy, the Milky Way, but is producing at least 10
times more stars. From the Earth, this object is seen as she was 650
million years after the Big-Bang. Her light has travelled about 13000
million years to reach the telescopes, being one of the brightest
galaxies discovered at such distances. In Astronomy, the further one
object is, the longer it takes for the light to reach us, and therefore
the Frontier Fields allow the astronomers to push the limits of the
observable Universe. This study provides new constraints on the density
and properties of the galaxies in the early Universe.
“Frontier Fields”
Last
month, during the meeting of the American Astronomical Society held at
Washington D.C. (USA), the Space Telescope Science Institute presented
its flagship project for the next 3 years: the “Hubble Frontier Fields".
In the framework of this program, three of the most powerful space
telescopes to date - Hubble, Spitzer and Chandra - will dedicate a large
amount of their observing time to observe six galaxies clusters, who
act as additional lenses and amplify the light from background sources,
including very faint galaxies to the edge of the observable Universe.
This will allow astronomers to study for the first time fainter and
smaller galaxies in the first billion years of the Universe.
The
first long exposure image of the cluster Abell 2744, obtained in the
last months, is the deepest one obtained so far of a cluster of galaxies
and is comparable to the previous Hubble Ultra Deep Field, which is a
blank region of the sky. All the Frontier Fields clusters have been
carefully selected and are the best ones for this kind of study.
Thanks
to the gravitational lensing by the cluster, the light of the
background galaxies can be magnified by a large amount. This effect
converts in practice the Hubble Space Telescope into an equivalent
telescope with a collecting area several hundred times larger.
Nicolas Laporte,
post-doctoral researcher at the IAC and expert in the search for very
distant galaxies, welcomes the high quality of the Hubble images: “we
expected to find very distant galaxies close to the cluster core, where
the light amplification is maximum. However, this galaxy is very close
to the edge of the Hubble image where the light is not strongly
amplified. We are really lucky that we could find it in the small field
of view of Hubble. In a related study led by Hakim Atek (EPFL, Lausanne) more galaxies are analyzed but none is more distant than Abell2744_Y1.”
The
analysis of the observations of this cluster carried out with the
Spitzer Space Telescope has been crucial to estimate the properties of
Abell2744_Y1. Alina Streblyanska, post-doctoral
researcher at the IAC, comments that the Spitzer observations combined
with the Hubble ones provide a good estimate of the distance to this
galaxy. “They also suggest that Abell2744_Y1 contains not only stars
but also a large amount of gas”.
Ismael Pérez-Fournon,
professor at the La Laguna University and head of the IAC group, points
out that last year his group contributed to the discovery of an
exceptional star factory in the early Universe, called HFLS3, with the
Herschel Space Observatory. “HFLS3 has extreme properties in the
far-infrared, observed 880 million years after the Big-Bang.
Abell2744_Y1 is a smaller galaxy, less massive but more distant and much
more representative of the early Universe. Both types of galaxies are
equally important to understand how galaxies formed and evolved.”
In
coordination with the Hubble observations, the Spitzer Space Telescope
and Chandra X-ray Observatory are taking very deep exposures of the
Frontier Fields. Since the end of 2013, the data of the first cluster
obtained by the first two telescopes are available to the whole
scientific community.
Observations of the Frontier Fields by
Hubble, Spitzer and Chandra are in an early stage but have already shown
the exceptional potential of this new project to study the first
luminous objects in the Universe. As it happnened with other Hubble
initiatives on deep fields, many other observatories all over the world
and in space will join the effort with additional observations of the
Frontier Fields. An unprecedented scientific legacy for future studies
with the present large telescopes as the Gran Telescopio Canarias (GTC),
and the future extremely large telescopes as the E-ELT and the James
Webb Space Telescope, is expected.
Publications:
- "The first Frontier Fields cluster: 4.5 micron excess in a z ~ 8 galaxy candidate in Abell 2744" N. Laporte et al., A&A Letters
- Probing the z>6 Universe with the first Hubble Frontier Fields cluster Abell 2744 H. Atek et al., arXiv1311.7670
Contacts:
- Nicolas Laporte: (nlaporte@iac.es) (+34) 922 605 752
- Ismael Pérez-Fournon: (ipf@iac.es) (+34) 922 605 257
- Alina Streblyanska: (alina@iac.es) (+34) 922 605 746
Title: Abell2744_Y1 galaxy
Description: Abell2744_Y1 is of the most distant galaxies in the early Universe discovered in the Hubble Frontier Fields. Credit: Gabriel Pérez – SMM (IAC)
