18 research outputs found
JPCam: A 1.2Gpixel camera for the J-PAS survey
JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10microm-pixel
16-channel detectors, to be deployed on a dedicated 2.55m wide-field telescope
at the OAJ (Observatorio Astrofisico de Javalambre) in Aragon, Spain. The
camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of
the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band
(~13.8nm) filters equi-spaced between 370 and 920nm plus 3 broad-band filters
to achieve unprecedented photometric red-shift accuracies for faint galaxies
over ~8000 square degrees of sky. The cryostat, detector mosaic and read
electronics is being supplied by e2v under contract to J-PAS while the
mechanical structure, housing the shutter and filter assembly, is being
designed and constructed by a Brazilian consortium led by INPE (Instituto
Nacional de Pesquisas Espaciais). Four sets of 14 filters are placed in the
ambient environment, just above the dewar window but directly in line with the
detectors, leading to a mosaic having ~10mm gaps between each CCD. The massive
500mm aperture shutter is expected to be supplied by the Argelander-Institut
fur Astronomie, Bonn. We will present an overview of JPCam, from the filter
configuration through to the CCD mosaic camera. A brief outline of the main
J-PAS science projects will be included.Comment: 11 pages and 9 figure
State of the Field: Extreme Precision Radial Velocities
The Second Workshop on Extreme Precision Radial Velocities defined circa 2015
the state of the art Doppler precision and identified the critical path
challenges for reaching 10 cm/s measurement precision. The presentations and
discussion of key issues for instrumentation and data analysis and the workshop
recommendations for achieving this precision are summarized here.
Beginning with the HARPS spectrograph, technological advances for precision
radial velocity measurements have focused on building extremely stable
instruments. To reach still higher precision, future spectrometers will need to
produce even higher fidelity spectra. This should be possible with improved
environmental control, greater stability in the illumination of the
spectrometer optics, better detectors, more precise wavelength calibration, and
broader bandwidth spectra. Key data analysis challenges for the precision
radial velocity community include distinguishing center of mass Keplerian
motion from photospheric velocities, and the proper treatment of telluric
contamination. Success here is coupled to the instrument design, but also
requires the implementation of robust statistical and modeling techniques.
Center of mass velocities produce Doppler shifts that affect every line
identically, while photospheric velocities produce line profile asymmetries
with wavelength and temporal dependencies that are different from Keplerian
signals.
Exoplanets are an important subfield of astronomy and there has been an
impressive rate of discovery over the past two decades. Higher precision radial
velocity measurements are required to serve as a discovery technique for
potentially habitable worlds and to characterize detections from transit
missions. The future of exoplanet science has very different trajectories
depending on the precision that can ultimately be achieved with Doppler
measurements.Comment: 45 pages, 23 Figures, workshop summary proceeding