A5049139877- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Optical Systems and Laser Technology
- Astronomical Observations and Instrumentation
- Astrophysics and Star Formation Studies
- Atmospheric and Environmental Gas Dynamics
- Calibration and Measurement Techniques
- Astrophysics and Cosmic Phenomena
- Atmospheric Ozone and Climate
- Astrophysical Phenomena and Observations
- Statistical and numerical algorithms
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Atmospheric aerosols and clouds
- Infrared Target Detection Methodologies
- Spectroscopy and Laser Applications
- Cryospheric studies and observations
- CCD and CMOS Imaging Sensors
- Solar and Space Plasma Dynamics
- Polar Research and Ecology
- Methane Hydrates and Related Phenomena
National Research Council Canada
2010-2025
Herzberg Institute of Astrophysics
2010-2025
The University of Texas at San Antonio
2020
Gemini South Observatory
2020
National Academies of Sciences, Engineering, and Medicine
1999-2014
University of California, Santa Cruz
2002-2004
University of Victoria
1998-2002
Canada–France–Hawaii Telescope
1999-2002
University of Hawaii System
1999-2002
We combine high-resolution images in four optical/infrared bands, obtained with the laser guide star adaptive optics (LGSAO) system on Keck telescope and Hubble Space Telescope (HST), to study gravitational lens SDSS J0737+3216 (lens redshift 0.3223, source 0.5812). show that (under favorable observing conditions) ground-based are comparable those HST terms of precision determination parameters both mass distribution background source. also quantify systematic errors associated incomplete...
Nighttime visible-light sky brightness and transparency are reported for the Polar Environment Research Laboratory (PEARL), located on a 610-m high ridge near Eureka research station, Ellesmere Island, Canada. Photometry of Polaris obtained in V band with PEARL All Sky Imager (PASI) over two winters is supported by standard meteorological measurements visual estimates conditions from sea level. These data show that during period study, October through March 2008/09 2009/10, zenith had mean...
Viewing high-redshift sources at near-opposite directions on the sky can ensure, using light-travel-time arguments, acausality between their emitted photons. One utility would be true random-number generation through sensing these via two independent telescopes that each flip a switch based latest-arrived colours; for example, to autonomously control quantum-mechanical (QM) experiment. Although demonstrated with distant quasars, those were not fully acausal pairs, which are restricted when...
As part of the Center for Adaptive Optics (AO) Treasury Survey (CATS) we imaged a set 15 intermediate redshift (z ∼ 0.8) luminous infrared (IR) galaxies (LIRGs) with Keck Laser Guide Star (LGS) AO facility. These were selected from Great Observatories Origins Deep (GOODS) southern field, allowing us to combine high spatial resolution Hubble Space Telescope optical (B, V, i, and z-bands) images our near-infrared (K'-band) study LIRG morphologies spatially resolved spectral energy...
Located within 10° of the North Pole, northern Ellesmere Island offers continuous darkness in winter months. This capability can greatly enhance detection efficiency planetary transit surveys and other time domain astronomy programs. We deployed two wide-field cameras at 80°N, near Eureka, Nunavut, for a 152 hr observing campaign 2012 February. The 16 megapixel camera systems were based on commercial f/1.2 lenses with 70 mm 42 apertures, they continuously imaged 504 1295 deg2, respectively....
We have observed nine QSOs with redshifts of 0.85 to 4.16 at near-infrared wavelengths PUEO, the Adaptive Optics (AO) Bonnette Canada-France-Hawaii Telescope. Exposure times ranged from 1500 24,000 s (mostly near 7000 s) in J, H, and/or K bands pixels 0035 on sky. The FWHMs co-added images location quasars are typically 016. Including another QSO published previously, we find associated structure least eight 10 objects, including z = 4.16. structures seen all cases include long, faint...
While optical and radio transient surveys have enjoyed a renaissance over the past decade, dynamic infrared sky remains virtually unexplored. The is powerful tool for probing events in dusty regions that high extinction, detecting coolest of stars are bright only at these wavelengths. fundamental roadblocks studying time-domain been overwhelmingly background (250 times brighter than optical) narrow field-of-view cameras (largest 0.6 sq deg). To begin to address challenges open new...
Ellesmere Island, at the most northerly tip of Canada, possesses highest mountain peaks within 10° pole. The is 2616 m, with many summits over 1000 high enough to place them above a stable low-elevation thermal inversion that persists through winter darkness. Our group has studied four mountains along northwestern coast have additional benefit smooth onshore airflow from ice-locked Arctic Ocean. We deployed small robotic site-testing stations three sites, which 1600 m and 8° Basic weather...
Near-infrared integral-field spectroscopy of redshifted [O iii], Hβ, and optical continuum emission from the z = 3.8 radio galaxy 4C+41.17 is presented, obtained with laser-guide-star adaptive optics facility on Gemini North telescope. Employing a specialized dithering technique, spatial resolution 010, or 0.7 kpc, achieved in each spectral element, velocity ∼70 km s−1. Spectra similar to local starbursts are found for bright knots coincident archival Hubble Space Telescope (HST) rest-frame...
Results of deploying a Differential Image Motion Monitor (DIMM) and DIMM combined with Multi-Aperture Scintillation Sensor (MASS/DIMM) are reported for campaigns in 2011 2012 on the roof Polar Environment Atmospheric Research Laboratory (PEARL). This facility is 610-m-high ridge at latitude 80 degrees N, near Eureka weatherstation Ellesmere Island, Canada. The median seeing 8-m elevation 0.85 arcsec or better based data alone, but dependent wind direction, likely includes component due to...
It has been suggested that the fuzzy nature of spacetime at Planck scale may cause lightwaves to lose phase coherence, and if severe enough this could blur images distant point-like sources sufficiently they do not form an Airy pattern focal plane a telescope. Blurring dramatic already observationally ruled out by from Hubble Space Telescope (HST), but I show underlying phenomenon still be stronger than previously considered. is harder detect, which explain why it gone unseen. A systematic...
Gamma-ray burst GRB221009A was of unprecedented brightness in the γ-rays and X-rays through to far ultraviolet, allowing for identification within a host galaxy at redshift z=0.151 by multiple space ground-based optical/near-infrared telescopes enabling first association—via cosmic-ray air-shower events—with photon 251 TeV. That is direct tension with potentially observable phenomenon quantum gravity (QG), where spacetime “foaminess” accumulates wavefronts propagating cosmological distances,...
Even though the technology of adaptive optics (AO) is rapidly maturing, calibration resulting images remains a major challenge. The AO point‐spread function (PSF) changes quickly in both time and position on sky. In typical observation, star used for guiding will be separated from scientific target by 10''–30''. This sufficient separation to render guide themselves nearly useless characterizing PSF at off‐axis position. A semiempirical technique described that improves determination PSF....
We present Keck diffraction-limited H-band photometry of a z ∼ 1.3 Type Ia supernova (SN) candidate, first identified in Hubble Space Telescope search for SNe massive high-redshift galaxy clusters. The adaptive optics (AO) data were obtained with the Laser Guide Star facility during four observing runs from 2005 September to November. In analysis run nearest maximum SN brightness, was found have magnitude H = 23.9 ± 0.14 (Vega). (approximately rest-frame R) light curve and provide detailed...
As part of a program to measure and evaluate atmospheric turbulence on mountains at the most northerly tip North America, we have deployed two SODARs lunar scintillometer Polar Environment Atmospheric Research Lab (PEARL) located 600m-high ridge near Eureka Ellesmere Island, 80° latitude. This paper discusses presents summary ground-layer seeing measurements from 2009-10 observing season.
We report results of a two-year campaign measurements, during arctic winter darkness, optical turbulence in the atmospheric boundary layer above Polar Environment Atmospheric Laboratory northern Ellesmere Island (latitude +80° N). The data reveal that ground-layer Arctic is often quite weak, even at comparatively low 610 m altitude this site. median and 25th percentile seeing, height 20 m, are found to be 0.57 0.25 arcsec, respectively. When combined with free-atmosphere component 0.30 total...
Most current astronomical adaptive optics (AO) systems rely on the availability of a bright star to measure distortion incoming wave front. Replacing guide with an artificial laser beacon alleviates this dependency stars and therefore increases sky coverage, but it does not eliminate another serious problem for AO observations. This is issue PSF variation time field position near star. In fact, because natural still necessary correction low‐order phase error, characterization (LGS) spatial...
We present the first measurements of near-infrared (NIR), specifically J-band, sky background in Canadian High Arctic. There has been considerable recent interest development an astronomical observatory Ellesmere Island; initial site testing shown promise for a world-class site. Encouragement our study came from on high Antarctic glacial plateau winter that showed markedly lower NIR emission when compared to good mid-latitude sites due reduced OH airglow lines. This is possibly Polar effect...
The Altair laser-guide-star adaptive optics facility combined with the near-infrared integral-field spectrometer on Gemini North have been employed to study morphology and kinematics of 3C 230 at z = 1.5, first such observations a high-redshift radio galaxy. These suggest bi-polar outflow spanning 09 (∼16 kpc projected distance for standard Λ CDM cosmology) reaching mean relative velocity 235 km s−1 in redshifted Hα +[N ii] [S emission. Structure is resolved 01 (0.8 kpc), which well...
We have undertaken a program of high-resolution imaging high-redshift radio galaxies (HzRGs), using adaptive optics on the Canada-France-Hawaii Telescope. report deep in J, H, and K bands six HzRGs redshift range 1.1 to 3.8. At these redshifts, near-infrared bandpasses sample rest-frame visible galactic light. The galaxy is resolved all fields generally elongated along axis lobes. These images are compared with archival Hubble Space Telescope Wide-Field Planetary Camera 2 optical...
We have employed natural guide star adaptive optics (AO) on the Keck II telescope to obtain near-infrared (H and K') images of three field galaxies, each redshift greater than 0.5. These are among highest-redshift non-active disk galaxies be imaged with AO. Each was chosen because it had been observed previously Hubble Space Telescope (HST) Wide Field Planetary Camera 2 (WFPC2) by others. Our AO in (NIR) closely match both depth high spatial resolution those optical data. Combining archival...
Nighttime sky-transparency statistics on Mauna Kea are reported based data from the Canada-France-Hawaii Telescope SkyProbe monitor. We focus period beginning with start of MegaCam wide-field optical imager operations in 2003 and continuing for almost three years. Skies were clear enough to observe 76% those nights; attenuations less than 0.2 mag up 60% time. An empirical model cloud attenuation duration is presented allowing us further characterize photometric conditions. This a good fit...
Abstract We report the latest results of 225 GHz atmospheric opacity measurements from two Arctic sites; one on high coastal terrain near Eureka weather station, Ellesmere Island, Canada, and other at Summit Station peak Greenland icecap. This is a campaign to search for site deploy new telescope submillimeter Very Long Baseline Interferometry THz astronomy in northern hemisphere. Since 2011, we have obtained 3 months winter data Eureka, about year Station. The indicate that these sites...
We report the first measurements of 225 GHz atmospheric opacity at Summit Camp (Latitude 72°.57 N; Longitude 38°.46 W; Altitude 3250 m) in Greenland and Polar Environment Atmospheric Research Laboratory (PEARL: Latitude 80°.05 86°.42 600 Northern Canada with a tipping radiometer. PEARL are research stations mostly interested meteorology geophysics, they potentially excellent sites for astronomical observations sub-millimeter wavelength. purchased radiometer from Radiometer Physics GmbH....