1,617 research outputs found
Wide-Field InfraRed Survey Telescope (WFIRST) Final Report
In December 2010, NASA created a Science Definition Team (SDT) for WFIRST,
the Wide Field Infra-Red Survey Telescope, recommended by the Astro 2010
Decadal Survey as the highest priority for a large space mission. The SDT was
chartered to work with the WFIRST Project Office at GSFC and the Program Office
at JPL to produce a Design Reference Mission (DRM) for WFIRST. Part of the
original charge was to produce an interim design reference mission by mid-2011.
That document was delivered to NASA and widely circulated within the
astronomical community. In late 2011 the Astrophysics Division augmented its
original charge, asking for two design reference missions. The first of these,
DRM1, was to be a finalized version of the interim DRM, reducing overall
mission costs where possible. The second of these, DRM2, was to identify and
eliminate capabilities that overlapped with those of NASA's James Webb Space
Telescope (henceforth JWST), ESA's Euclid mission, and the NSF's ground-based
Large Synoptic Survey Telescope (henceforth LSST), and again to reduce overall
mission cost, while staying faithful to NWNH. This report presents both DRM1
and DRM2.Comment: 102 pages, 57 figures, 17 table
The Emergence of the Modern Universe: Tracing the Cosmic Web
This is the report of the Ultraviolet-Optical Working Group (UVOWG)
commissioned by NASA to study the scientific rationale for new missions in
ultraviolet/optical space astronomy approximately ten years from now, when the
Hubble Space Telescope (HST) is de-orbited. The UVOWG focused on a scientific
theme, The Emergence of the Modern Universe, the period from redshifts z = 3 to
0, occupying over 80% of cosmic time and beginning after the first galaxies,
quasars, and stars emerged into their present form. We considered
high-throughput UV spectroscopy (10-50x throughput of HST/COS) and wide-field
optical imaging (at least 10 arcmin square). The exciting science to be
addressed in the post-HST era includes studies of dark matter and baryons, the
origin and evolution of the elements, and the major construction phase of
galaxies and quasars. Key unanswered questions include: Where is the rest of
the unseen universe? What is the interplay of the dark and luminous universe?
How did the IGM collapse to form the galaxies and clusters? When were galaxies,
clusters, and stellar populations assembled into their current form? What is
the history of star formation and chemical evolution? Are massive black holes a
natural part of most galaxies? A large-aperture UV/O telescope in space
(ST-2010) will provide a major facility in the 21st century for solving these
scientific problems. The UVOWG recommends that the first mission be a 4m
aperture, SIRTF-class mission that focuses on UV spectroscopy and wide-field
imaging. In the coming decade, NASA should investigate the feasibility of an 8m
telescope, by 2010, with deployable optics similar to NGST. No high-throughput
UV/Optical mission will be possible without significant NASA investments in
technology, including UV detectors, gratings, mirrors, and imagers.Comment: Report of UV/O Working Group to NASA, 72 pages, 13 figures, Full
document with postscript figures available at
http://casa.colorado.edu/~uvconf/UVOWG.htm
Extragalactic Planetary Nebulae: Observational Challenges & Future Prospects
The study of extragalactic planetary nebulae (EPN) is a rapidly expanding
field. The advent of powerful new instrumentation such as the PN spectrograph
has led to an avalanche of new EPN discoveries both within and between
galaxies. We now have thousands of EPN detections in a heterogeneous selection
of nearby galaxies and their local environments, dwarfing the combined galactic
detection efforts of the last century. Key scientific motivations driving this
rapid growth in EPN research and discovery have been the use of the PNLF as a
standard candle, as dynamical tracers of their host galaxies and dark matter
and as probes of Galactic evolution. This is coupled with the basic utility of
PN as laboratories of nebula physics and the consequent comparison with theory
where population differences, abundance variations and star formation history
within and between stellar systems informs both stellar and galactic evolution.
Here we pose some of the burning questions, discuss some of the observational
challenges and outline some of the future prospects of this exciting,
relatively new, research area as we strive to go fainter, image finer, see
further and survey faster than ever before and over a wider wavelength regimeComment: 4 pages, no figures, LaTeX, to be published in Proceedings of the ESO
workshop on Planetary Nebulae beyond the Milky Way held at ESO, Garching, May
19-21, 200
The Search for Extraterrestrial Intelligence (SETI)
A bibliography of reports concerning the Search for Extraterrestrial Intelligence is presented. Cosmic evolution, space communication, and technological advances are discussed along with search strategies and search systems
Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
Precision astrometry at microarcsecond accuracy has application to a wide
range of astrophysical problems. This paper is a study of the science questions
that can be addressed using an instrument that delivers parallaxes at about 4
microarcsec on targets as faint as V = 20, differential accuracy of 0.6
microarcsec on bright targets, and with flexible scheduling. The science topics
are drawn primarily from the Team Key Projects, selected in 2000, for the Space
Interferometry Mission PlanetQuest (SIM PlanetQuest). We use the capabilities
of this mission to illustrate the importance of the next level of astrometric
precision in modern astrophysics. SIM PlanetQuest is currently in the detailed
design phase, having completed all of the enabling technologies needed for the
flight instrument in 2005. It will be the first space-based long baseline
Michelson interferometer designed for precision astrometry. SIM will contribute
strongly to many astronomical fields including stellar and galactic
astrophysics, planetary systems around nearby stars, and the study of quasar
and AGN nuclei. SIM will search for planets with masses as small as an Earth
orbiting in the `habitable zone' around the nearest stars using differential
astrometry, and could discover many dozen if Earth-like planets are common. It
will be the most capable instrument for detecting planets around young stars,
thereby providing insights into how planetary systems are born and how they
evolve with time. SIM will observe significant numbers of very high- and
low-mass stars, providing stellar masses to 1%, the accuracy needed to
challenge physical models. Using precision proper motion measurements, SIM will
probe the galactic mass distribution and the formation and evolution of the
Galactic halo. (abridged)Comment: 54 pages, 28 figures, uses emulateapj. Submitted to PAS
Microarcsecond astrometry with Gaia: the solar system, the Galaxy and beyond
Gaia is an all sky, high precision astrometric and photometric satellite of
the European Space Agency (ESA) due for launch in 2010-2011. Its primary
mission is to study the composition, formation and evolution of our Galaxy.
Gaia will measure parallaxes and proper motions of every object in the sky
brighter than V=20, amounting to a billion stars, galaxies, quasars and solar
system objects. It will achieve an astrometric accuracy of 10muas at V=15 -
corresponding to a distance accuracy of 1% at 1kpc. With Gaia, tens of millions
of stars will have their distances measured to a few percent or better. This is
an improvement over Hipparcos by several orders of magnitude in the number of
objects, accuracy and limiting magnitude. Gaia will also measure radial
velocities for source brighter than V~17. To characterize the objects, each
object is observed in 15 medium and broad photometric bands with an onboard CCD
camera. With these capabilities, Gaia will make significant advances in a wide
range of astrophysical topics. These include a detailed kinematical map of
stellar populations, stellar structure and evolution, the discovery and
characterization of thousands of exoplanetary systems and General Relativity on
large scales. I give an overview of the mission, its operating principles and
its expected scientific contributions. For the latter I provide a quick look in
five areas on increasing scale size in the universe: the solar system, exosolar
planets, stellar clusters and associations, Galactic structure and
extragalactic astronomy.Comment: (Errors corrected) Invited paper at IAU Colloquium 196, "Transit of
Venus: New Views of the Solar System and Galaxy". 14 pages, 6 figures.
Version with higher resolution figures available from
http://www.mpia-hd.mpg.de/homes/calj/gaia_venus2004.htm
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