11 research outputs found
The JANUS X-Ray Flash Monitor
JANUS is a NASA small explorer class mission which just completed phase A and
was intended for a 2013 launch date. The primary science goals of JANUS are to
use high redshift (6<z<12) gamma ray bursts and quasars to explore the
formation history of the first stars in the early universe and to study
contributions to reionization. The X-Ray Flash Monitor (XRFM) and the Near-IR
Telescope (NIRT) are the two primary instruments on JANUS. XRFM has been
designed to detect bright X-ray flashes (XRFs) and gamma ray bursts (GRBs) in
the 1-20 keV energy band over a wide field of view (4 steradians), thus
facilitating the detection of z>6 XRFs/GRBs, which can be further studied by
other instruments. XRFM would use a coded mask aperture design with hybrid CMOS
Si detectors. It would be sensitive to XRFs/GRBs with flux in excess of
approximately 240 mCrab. The spacecraft is designed to rapidly slew to source
positions following a GRB trigger from XRFM. XRFM instrument design parameters
and science goals are presented in this paper.Comment: submitted to Proc. SPIE, Vol. 7435 (2009), 7 pages, 8 figure
Surface and Temporal Biosignatures
Recent discoveries of potentially habitable exoplanets have ignited the
prospect of spectroscopic investigations of exoplanet surfaces and atmospheres
for signs of life. This chapter provides an overview of potential surface and
temporal exoplanet biosignatures, reviewing Earth analogues and proposed
applications based on observations and models. The vegetation red-edge (VRE)
remains the most well-studied surface biosignature. Extensions of the VRE,
spectral "edges" produced in part by photosynthetic or nonphotosynthetic
pigments, may likewise present potential evidence of life. Polarization
signatures have the capacity to discriminate between biotic and abiotic "edge"
features in the face of false positives from band-gap generating material.
Temporal biosignatures -- modulations in measurable quantities such as gas
abundances (e.g., CO2), surface features, or emission of light (e.g.,
fluorescence, bioluminescence) that can be directly linked to the actions of a
biosphere -- are in general less well studied than surface or gaseous
biosignatures. However, remote observations of Earth's biosphere nonetheless
provide proofs of concept for these techniques and are reviewed here. Surface
and temporal biosignatures provide complementary information to gaseous
biosignatures, and while likely more challenging to observe, would contribute
information inaccessible from study of the time-averaged atmospheric
composition alone.Comment: 26 pages, 9 figures, review to appear in Handbook of Exoplanets.
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