25 research outputs found
Preliminary DIMM and MASS Nighttime Seeing Measurements at PEARL, in the Canadian High Arctic
Results of deploying a Differential Image Motion Monitor (DIMM) and a DIMM
combined with a Multi-Aperture Scintillation Sensor (MASS/DIMM) are reported
for campaigns in 2011 and 2012 on the roof of the Polar Environment Atmospheric
Research Laboratory (PEARL). This facility is on a 610-m-high ridge at latitude
80 degrees N, near the Eureka weatherstation on Ellesmere Island, Canada. The
median seeing at 8-m elevation is 0.85 arcsec or better based on DIMM data
alone, but is dependent on wind direction, and likely includes a component due
to the PEARL building itself. Results with MASS/DIMM yield a median seeing less
than 0.76 arcsec. A semi-empirical model of seeing versus ground wind speed is
introduced which allows agreement between these datasets, and with previous
boundary-layer profiling by lunar scintillometry from the same location. This
further suggests that best 20 percentile seeing reaches 0.53 arcsec, of which
typically 0.30 arcsec is due to the free atmosphere. Some discussion for
guiding future seeing instrumentation and characterization at this site is
provided.Comment: 16 pages, 11 figures, accepted for PAS
Three Lyman-alpha Emitters at z approx 6: Early GMOS/Gemini Data from the GLARE Project
We report spectroscopic detection of three z~6 Lyman-alpha emitting galaxies,
in the vicinity of the Hubble Ultra Deep Field, from the early data of the
Gemini Lyman- at Reionisation Era (GLARE) project. Two objects,
GLARE#3001 (z =5.79) and GLARE#3011 (z =5.94), are new detections and are
fainter in (z'_{AB} =26.37 and 27.15) than any Lyman break galaxy
previously detected in Lyman-alpha. A third object, GLARE#1042 (z =5.83) has
previously been detected in line emission from the ground; we report here a new
spectroscopic continuum detection. Gemini/GMOS-S spectra of these objects,
obtained using nod & shuffle, are presented together with a discussion of their
photometric properties. All three objects were selected for spectroscopy via
the i-drop Lyman Break technique, the two new detections from the GOODS v1.0
imaging data. The red i'-z' colors and high equivalent widths of these objects
suggest a high-confidence z>5 Lyman-alpha identification of the emission lines.
This brings the total number of known z>5 galaxies within 9 arcmin of the
Hubble Ultra Deep Field to four, of which three are at the same redshift (z=5.8
within 2000 km/s suggesting the existence of a large-scale structure at this
redshift.Comment: 5 pages, 2 figures. Revised to match accepted versio
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
Ukaliq: Seeing long-term with small, precise arctic telescopes
Time-domain astrophysics benefits from extreme-latitude sites, which can combine intrinsically extended nighttime with good sky conditions. One such location is the Polar Environment Atmospheric Research Laboratory (PEARL), at 80\ub0 North latitude, on the northwestern edge of Ellesmere Island, Canada. Experience gained deploying seeing monitors there has been incorporated into an automated system called "Ukaliq" after the common arctic hare, which is also very well suited to its local environment. Even with modest aperture, high photometric reliability may be achieved using simple adaptive optics together with observing strategies that best fit the unique set of advantages available at PEARL: excellent image quality maintained during many clear, calm, dark periods of 100 hours or more. A potential multi-year search for gravitational microlensing of quasars with Ukaliq helps illustrate this niche in the era of large wide-field survey facilities.Peer reviewed: YesNRC publication: Ye