A5071986979- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Particle Accelerators and Free-Electron Lasers
- Optical Systems and Laser Technology
- Planetary Science and Exploration
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Atmospheric Ozone and Climate
- Advanced optical system design
- High-pressure geophysics and materials
- Optical Wireless Communication Technologies
- Photonic and Optical Devices
- Photocathodes and Microchannel Plates
- Infrared Target Detection Methodologies
- Isotope Analysis in Ecology
- Advanced X-ray Imaging Techniques
- Spectroscopy and Laser Applications
W.M. Keck Observatory
2013-2024
Nia Association
2006
University of Minnesota
2001-2005
University of Hawaiʻi at Mānoa
2005
European Southern Observatory
2005
University of Maryland, College Park
2005
University of Liège
2005
Pomona College
2005
Goddard Space Flight Center
2005
Rowan University
2005
We report the results of an extensive imaging and spectroscopic survey in Great Observatories Origins Deep Survey (GOODS)-North field completed using DEIMOS on Keck II telescope. Observations 2018 targets a magnitude-limited sample 2911 objects to RAB = 24.4 yield secure redshifts for 1440 galaxies active galactic nuclei (AGNs) plus 96 stars. In addition associated quality assessments, our catalog also includes photometric astrometric measurements all detected R-band GOODS-North region....
We quantified eight parent volatiles (H 2 O, C H 6 , HCN, CO, CH 3 OH, and 4 ) in the Jupiter-family comet Tempel 1 using high-dispersion infrared spectroscopy wavelength range 2.8 to 5.0 micrometers. The abundance ratio for ethane was significantly higher after impact, whereas those methanol hydrogen cyanide were unchanged. ratios ejecta are similar most Oort cloud comets, but acetylene lower by a factor of about 2. These results suggest that volatile ices comets originated common region...
Gravitational redshift in the Galactic Center General relativity predicts that light emitted by an object a strong gravitational field—for example, close to black hole—should be shifted longer wavelengths. This does not exist Newtonian theory of gravity. Do et al. monitored position and spectrum star S0-2 as it passed Sagittarius A*, supermassive hole at center Milky Way. Around closest part S0-2's 16-year orbit, they detected effect on its spectrum. These results are more consistent with...
We present an overview of the OSIRIS integral field spectrograph which was recently commissioned on Keck II Telescope. works with Adaptive Optics system and utilizes infrared transmissive lenslet array to sample a rectangular view at close diffraction limit. By packing spectra together (2 pixel rows per spectrum) using Rockwell Hawaii-2 detector (wavelengths between 1 2.5 microns), we achieve relatively large (up 6."4) while maintaining full broad-band spectral coverage resolution 3800....
We imaged five objects near the star forming clouds of Ophiuchus with Keck Laser Guide Star AO system. resolved Allers et al. (2006)'s #11 (Oph 16222-2405) and #16 16233-2402) into binary systems. The object is a 243 AU binary, widest known for very low mass (VLM) binary. nature was discovered first by (2005) independently here during which we obtained spatially R~2000 near-infrared (J & K) spectra, mid-IR photometry, orbital motion estimates. estimate 11A 11B gravities (log(g)>3.75),...
We present Keck-I MOSFIRE near-infrared spectroscopy for a sample of 13 compact star-forming galaxies (SFGs) at redshift 2 ⩽ z 2.5 with star formation rates SFR ∼ 100 M☉ yr−1 and masses log(M/M☉) ∼10.8. Their high integrated gas velocity dispersions σint km s−1, as measured from emission lines Hα [O iii], the resultant M⋆–σint relation M⋆–Mdyn all match well to those quiescent 2, stellar absorption lines. Since log(M⋆/Mdyn) =−0.06 ± 0.2 dex, these SFGs appear be dynamically relaxed evolved,...
We report the first detection of a credible progenitor system for Type Ic supernova (SN Ic), SN 2017ein. present spectra and photometry SN, finding it to be similar carbon-rich, low-luminosity SNe Ic. Using post-explosion Keck adaptive optics image, we precisely determine position 2017ein in pre-explosion \hst\ images, single source coincident with position. This is marginally extended, consistent being stellar cluster. However, under assumption that emission this dominated by point source,...
NGC 3147, 4698, and 1ES 1927+654 are active galaxies that classified as Seyfert 2s, based on the line ratios of strong narrow emission lines in their optical spectra. However, they exhibit rapid X-ray spectral variability and/or little indication obscuration fitting, contrary to expectation from galactic nucleus (AGN) unification model. Using spectropolarimetry with LRIS near-infrared spectroscopy NIRSPEC at W. M. Keck Observatory, we conducted a deep search for hidden polarized broad Hα...
Nova V2362 Cygni has undergone a number of very unusual changes. Ground-based spectroscopy initially revealed normal sequence events: the object faded and its near-infrared emission lines gradually shifted to higher excitation conditions until about day 100 when optical fading reversed slowly brightened. This was accompanied by rise in Swift X-ray telescope flux sudden shift visible IR spectrum back low levels. The new lower broad line widths many P-Cygni profiles, all indicative ejection...
OSIRIS is a near-infrared integral field spectrograph operating behind the adaptive optics system at W. M. Keck Observatory. While has been scientifically productive instrument to date, its sensitivity limited by grating efficiency that less than half of what was expected. The spatially averaged old grating, weighted error, measured be 39.5% ± 0.8% λ = 1.310 μm, with large field-dependent variation 11.7% due across surface. Working new vendor, we developed more efficient and uniform average...
General relativity can be tested in the strong gravity regime by monitoring stars orbiting supermassive black hole at Galactic Center with adaptive optics. However, limiting source of uncertainty is spatial PSF variability due to atmospheric anisoplanatism and instrumental aberrations. The Group UCLA has completed a project developing algorithms predict for Keck AO images. We have created new software package (AIROPA), based on modified versions StarFinder Arroyo, that takes turbulence...
We present spatially resolved infrared spectra of V723 Cas (Nova Cassiopeia 1995) obtained over four years with the integral field spectrograph OSIRIS on Keck II. Also presented are one epoch unresolved from long slit NIRSPEC The observations made use laser guide star adaptive optics facility that produced diffraction-limited spatial resolution strong coronal emission features in nova ejecta. remove point-like continuum data cubes to reveal details extended nebula and find due [Si vi] [Ca...
We present observations of the classical nova V723 Cassiopeiae (Nova Cas 1995), obtained both with Infrared Space Observatory (ISO) and from ground. The infrared spectrum was dominated in first year by H He recombination lines, at later times coronal lines. lines imply a reddening E(B-V) = 0.78, an electron temperature 7000 K, density 2 × 108 cm-3 on day 250. argue that high-ionization species are most likely result collisional ionization rather than photoionization therefore truly...
We report optical photometry and through mid-infrared spectroscopy of the classical nova V1186 Sco. This slowly developing had a complex light curve with multiple secondary peaks similar to those seen in PW Vul. The time decline 2 mag, t2, was 20 days, but erratic nature makes determination intrinsic properties based on (e.g., luminosity) problematic, often-cited relationship maximum magnitude versus rate decay Della Valle & Livio fails yield plausible distance. Spectra covering 0.35-35 μm...
We report on the preliminary design of W.M. Keck Observatory's (WMKO's) next-generation adaptive optics (NGAO) facility. This facility is designed to address key science questions including understanding formation and evolution today's galaxies, measuring dark matter in our galaxy beyond, testing theory general relativity Galactic Center, planetary systems around nearby stars, exploring origins own solar system. The requirements derived from these have resulted NGAO being near...
We present the results of upgrade spectrograph detector in integral field spectrograph, OSIRIS. OSIRIS is a near-infrared (1 to 2.5 microns) on Keck I telescope. This instrument produces up 3,000 spectra simultaneously over contiguous rectangular view with spectral resolution ~3,800. works Adaptive Optics system achieve diffraction-limited spatial and has four plate scales ranging from 0.02 0.10 arcseconds. At first light 2005, portion was equipped Rockwell Hawaii-2 detector. have now...
We present the design of SCALES (Slicer Combined with Array Lenslets for Exoplanet Spectroscopy) a new 2-5 micron coronagraphic integral field spectrograph under construction Keck Observatory. enables low-resolution (R∼50) spectroscopy, as well medium-resolution (R∼4,000) spectroscopy goal discovering and characterizing cold exoplanets that are brightest in thermal infrared. Additionally, has 12x12" field-of-view imager will be used general adaptive optics science at Keck. SCALES's...
We report on an unprecedented infrared time series of spectra V1187 Sco, a very fast ONeMg nova. The observations covered 56 day period (2004 August 6-September 30) starting 2 days after the nova's peak brightness. Time evolution revealed changing line strengths and profiles timescales less than to weeks as nova evolved from early postmaximum coronal phases. When our ground-based optical Spitzer Space Telescope data were combined, wavelength coverage 0.38-36 μm allowed accurate spectral...
We present phase-resolved near-infrared photometry and spectroscopy of the classical nova V1500 Cyg to explore whether cyclotron emission is in this system. While do not indicate presence discrete harmonic emission, light curves suggest that a sizable fraction its fluxes are due component. The appear remain dominated by from heated face secondary star have used infrared search for other potential magnetic systems amongst old novae. found V1974 superficially resemble those Cyg, suggesting...
SCALES (Santa Cruz Array of Lenslets for Exoplanet Spectroscopy) is a 2-5 micron high-contrast lenslet integral-field spectrograph (IFS) driven by exoplanet characterization science requirements and will operate at W. M. Keck Observatory. Its fully cryogenic optical train uses custom silicon array, selectable coronagraphs, dispersive prisms to carry out integral field spectroscopy over 2.2 arcsec view with low (< 300) spectral resolution. A small, dedicated section the array feeds an image...
We present spectroscopic observations of the classical nova CP Crucis (Nova Crux 1996) obtained with Infrared Space Observatory Short Wavelength Spectrometer (ISO SWS) and Anglo-Australian Telescope using both Imaging Spectrograph Royal Greenwich Spectrograph. From expansion parallax, we find that lies at a distance 2.6 ± 0.5 kpc reached maximum MV -8.7 0.96 days after discovery. abundance enhancements versus solar by mass 75, 17, 27 for N, O, Ne, respectively. Additionally, constrain Mg in...