Access to the
UV range is fundamental for astrophysics since thermal phenomena at
temperatures T>10,000 K occur in a wide range of astophysical events, with flux
emission mostly in the UV. Moreover, UV spectroscopic and imaging capabilities
are a fundamental tool to study plasmas at temperatures in the 3,000-300,000 K
range. Also, the electronic transitions of the most abundant molecules in the
CO, OH, CS, CO2+, CO2) are in the UV range. The
UV radiation field is also a powerful astrochemical
and photoionizing agent.
Optical observations provide most of the standards for the study of
stellar populations, and, coupled with UV observations, the rest frame
fundamental information for the population synthesis models, and therefore the
study of stellar population of high-z objects.
The scientific plans for
WSO-UV are very ambitious, and span all of the astronomical research branches.
WSO-UV will be operating in the second decade of this century, and it will be a
fundamental tool for the development of astronomical knowledge, fully integrated
with the many other space and ground-based observatories.
WSO-UV will give a
significant contribution to solve the key astronomical problems individuated by
formulated by the ASTRONET consortium,
and which are driving the
Agency “Cosmic Vision” program and the
NASA “Origins” program.
In particular, the data collected by WSO-UV will be used to answer to the
following questions (as formulated by the ASTRONET consortium):
Do we understand the extreme of the
Universe? Important inputs for this problem will come from WSO-UV
observations of: supernovae, gamma ray bursts, interacting binaries (millisecond
pulsars, low-mass X-ray binaries, cataclysmic variables, blue stragglers,
etc.), as well as observations of active galactic nuclei, their surrounding
environment, and the accretion and outflow processes in their central black
How do galaxies form and evolve?
Important inputs for this problem will come from WSO-UV surveys in far-UV
and near-UV of galaxy clusters at different redshifts, of the Virgo cluster,
and from the extension to the far-UV and near UV of the GOODS ultra deep
field survey. Surface brightness fluctuation technique will be used to
investigate the unresolved stellar population in distant galaxies, while
far-UV and near UV observations of galaxies in the local universe up to z>1
will be used to solve the still open problem of the UV-upturn in early-type
galaxies and in bulges. Particular effort will be devoted to the origin and
early evolution of our Galaxy, using as fundamental probe, among others, the
Galactic globular cluster system.
What is the origin and evolution of
stars and planets? Important inputs for this problem will come from
WSO-UV observations of the stellar population in different environments
(stellar associations, open and globular clusters, Local Group galaxies,
including the dwarf satellites of our Galaxy). WSO-UV observations will
provide fundamental inputs in the study of young stellar objects, including
the processes of accretion and outflow. Additional information on stellar
structure and evolution will come from asteroseismological studies, from the
study of stellar magnetic activity, and of stellar variability. Efforts will
also be devoted to the study of the interstellar medium. WSO-UV will also
provide important data for the study of the extrasolar planet atmospheres (including
a number of biomarkers). Also the study of Solar System bodies will benefit
from observations with the different instruments onboard of WSO-UV.
Moreover, with the synergy of
HST archive, WSO-UV will allow long term
photometric and spectroscopic monitoring of a variety of astronomical objects.
Moreover, the extended temporal coverage with high angular resolution UV-optical
imaging will allow the measurement of relative and absolute proper motions with
unprecedented accuracy, de facto opening a new, completely unexplored research
branch. Astronomers have just started to exploit this possibility. If properly
equipped with cameras with diffraction limit imaging capabilities, WSO-UV will
give the opportunity to fully develop this research activity, allowing proper
motion measurements with the same accuracy of
GAIA, but in a
fully complementary way. WSO-UV+HST proper motions will be measured down
to much fainter targets than
GAIA, and in
much more crowded environments. And all this will be done many years before the
final catalog of
GAIA will be available.
For More Information
A detailed discussion on the WSO-UV possible
contributions to the
is given in the book FCU Phase A
Study Report relesead
by the WSO-UV
Italian Team. This document shall not be considered neither
balanced nor fully representative of the scientific priorities either of the
astronomical communities of the WSO-UV funding countries nor of the
international community at large that will use WSO-UV. However, the scientific
case here presented has driven to the precise definition of the science
requirements for the imagers instruments on board of WSO-UV: the
Field Camera Unit (FCU).