and Cosmology

10. Outlook
407
In the final chapter of this book, we will dare to give
an outlook for the fields of extragalactic astronomy and
cosmology for the next few years from the perspective
of 2006.
Progress in (extragalactic) astronomy is achieved
through information obtained from increasingly improving
instruments and by refining our theoretical
understanding of astrophysical processes, which in turn
is driven by observational results. It is easy to foresee
that the evolution of instrumental capabilities will
continue rapidly in the near future, enabling us to perform
better and more detailed studies of cosmic sources.
A few examples illustrating this statement will be given
here. The size of optical wide-field cameras had reached
a value of ∼ (20 000) 2 pixels by 2003 with the installment
of Megacam at the CFHT. This multi-chip camera
allows the mapping of one square degree of the sky
Fig. 10.1. Wide-field cameras, attached to telescopes on sites
with excellent atmospheric conditions, can obtain detailed
images of a large number of objects simultaneously. This
is illustrated here with the CFH12K camera at the CFHT.
Numbers in each panel, which show subsequent enlargements,
denote the number of pixels displayed, where the pixel size is
0 ′′ . 2
in a single exposure and, with a pixel size of 0 ′′ . 2, it
is well matched to the excellent seeing conditions typically
met on Mauna Kea (see Fig. 10.1). Additional
instruments with similar characteristics have been recently
finished or are about to be commissioned. One
of them is OmegaCAM, a square-degree camera at the
newly-built VLT Survey Telescope on Paranal. Furthermore,
the development of NIR detectors is rapid, and
soon wide-field cameras in the NIR regime will be considerably
larger than current ones. For instance, in 2007
the new 4-meter telescope VISTA will go into operation
on Paranal, which will be equipped initially with
a single instrument, a wide-field NIR camera. The combination
of deep and wide optical and NIR images will
no doubt lead to great strides in astronomy. For example,
in the field of galaxy surveys, accurate photometric
redshifts will become available. The same holds true
for weak gravitational lensing or the search for very
rare objects, for which surveying large regions of the
sky is obviously necessary.
Within only a decade, the total collecting area of
large optical telescopes has increased by a large factor,
as is illustrated in Fig. 10.2. At the present time, about
10 telescopes of the 10-meter class are in operation, the
first of which, Keck I, was put into operation in 1993. In
addition, the development of adaptive optics will allow
us to obtain diffraction-limited angular resolution from
ground-based observations (see Fig. 10.3).
In another step to improve angular resolution, optical
and NIR interferometry will increasingly be employed.
For example, the two Keck telescopes (Fig. 1.28) are
mounted such that they can be used for interferometry.
The four unit telescopes of the VLT can be combined,
either with each other or with additional (auxiliary)
smaller telescopes, to act as an interferometer (see
Fig. 1.31). The auxiliary telescopes can be placed at
different locations, thus yielding different baselines
and thereby increasing the coverage in angular resolution.
Finally, the Large Binocular Telescope (LBT),
which consists of two 8.4-meter telescopes mounted
on the same platform, was developed and constructed
for the specific purpose of optical and NIR interferometry
and had first light in October 2005. Once in
operation, expected to occur by the end of 2006, this
Peter Schneider, Outlook.
In: Peter Schneider, Extragalactic Astronomy and Cosmology. pp. 407–414 (2006)
DOI: 10.1007/11614371_10 © Springer-Verlag Berlin Heidelberg 2006