A5027295582- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Space Science and Extraterrestrial Life
- Neutrino Physics Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Dark Matter and Cosmic Phenomena
- Planetary Science and Exploration
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Black Holes and Theoretical Physics
- Particle Accelerators and Free-Electron Lasers
- Calibration and Measurement Techniques
- Particle Detector Development and Performance
- Medical Imaging Techniques and Applications
- Superconducting Materials and Applications
- Astro and Planetary Science
- Space exploration and regulation
- Atomic and Subatomic Physics Research
- Cosmology and Gravitation Theories
University of California, San Diego
2016-2024
W.M. Keck Observatory
2024
Harvard University
2023
University of California, Santa Cruz
2001-2023
University of Delaware
2023
University of California, Berkeley
2009-2023
Center for Astrophysics Harvard & Smithsonian
2023
University of California, Irvine
2009-2022
National Research Council Canada
2018
University of Cambridge
2012-2017
We present an overview of a new integral field spectroscopic survey called MaNGA (Mapping Nearby Galaxies at Apache Point Observatory), one three core programs in the fourth-generation Sloan Digital Sky Survey (SDSS-IV) that began on 2014 July 1. will investigate internal kinematic structure and composition gas stars unprecedented sample 10,000 nearby galaxies. summarize essential characteristics instrument design context MaNGA's key science goals prototype observations to demonstrate...
We present the results of a spectroscopic survey kinematic structure star-forming galaxies at redshift z ∼ 2–3 using Keck/OSIRIS integral field spectroscopy. Our sample is comprised 12 between redshifts 2.0 and 2.5 one galaxy 3.3 which are well detected in either Hα or [O iii] emission. These generally representative mean stellar mass similar redshifts, although they tend to have star formation rate surface densities slightly higher than mean. observations were obtained conjunction with Keck...
We report the detection of a variable point source, imaged at L'(3.8 microns) with W. M. Keck II 10-meter telescope's adaptive optics system, that is coincident to within 18 mas Galaxy's central supermassive black hole and unique radio source Sgr A*. While in 2002 this (SgrA*-IR) was confused stellar S0-2, 2003 these two sources are separated by 87 allowing new source's properties be determined directly. On four separate nights, its observed L' magnitude ranges from 12.2 13.8, which...
(Abridged) To investigate the black hole mass (MBH) vs. stellar velocity dispersion relation of active galaxies, we measured dispersions a sample local Seyfert 1 for which have recently determined MBH using reverberation mapping. For most objects, were from high S/N ratio optical spectra centered on Ca II triplet region (~8500 A), obtained at Keck, Palomar, and Lick Observatories. two in was contaminated by nuclear emission, measurement based high-quality H-band with OSIRIS Keck-II...
We present stellar kinematics and orbit superposition models for the central regions of four brightest cluster galaxies, based upon integral-field spectroscopy at Gemini, Keck, McDonald Observatories. Our data span radii from <100 pc to tens kiloparsecs, comparable effective radius each galaxy. report black hole masses, M•, 2.1+1.6−1.6 × 1010 M☉ NGC 4889, 9.7+3.0−2.5 109 3842, 1.3+0.5−0.4 7768, with errors representing 68% confidence limits. For 2832, we an upper limit M• < 9.0 M☉. galaxy...
Strong gravitational lenses can be used to detect low-mass subhaloes, based on deviations in image fluxes and positions from what achieved with a smooth mass distribution. So far, this method has been limited by the small number of (radio-loud, microlensing-free) systems which analysed for presence substructure. Using lens B1422+231, we demonstrate that adaptive optics integral field spectroscopy also dark substructures. We analyse data obtained OH Suppressing Infra-Red Imaging Spectrograph...
We present new high angular resolution near-infrared spectroscopic observations of the nuclear star cluster surrounding Milky Way's central supermassive black hole. Using integral-field spectrograph OSIRIS on Keck II behind laser-guide-star adaptive optics system, this survey enables us to separate early-type (young, 4-6 Myr) and late-type (old, >1 Gyr) stars with a completeness 50% down K' = 15.5 mag, which corresponds ~10 \msun for stars. This work increases radial extent reported...
Strong gravitational lensing provides a powerful test of cold dark matter (CDM) as it enables the detection and mass measurement low-mass haloes even if they do not contain baryons. Compact lensed sources such active galactic nuclei (AGNs) are particularly sensitive to perturbing subhaloes, but their use CDM has been limited by small number systems which have significant radio emission that is extended enough avoid stars in plane lens galaxy, red be minimally affected differential dust...
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 present early results from an ongoing study of the kinematic structure star-forming galaxies at redshift z ~ 2-3 using integral-field spectroscopy rest-frame optical nebular emission lines in combination with Keck laser guide star adaptive optics (LGSAO). show maps three target Q1623-BX453, Q0449-BX93, and DSF 2237a-C2 located redshifts = 2.1820, 2.0067, 3.3172, respectively, each which is well resolved a PSF measuring approximately 0.11''-0.15'' (~900-1200 pc 2-3) after cosmetic...
We present 0.2" resolution near-infrared integral field spectroscopy of H-alpha emission from six star forming galaxies at z~1.6 (look-back time ~9.6 Gyr). These observations were obtained with OSIRIS using the Keck Laser Guide Star Adaptive Optics system. All sources have a compact spatial extent ~1", an average half light radius r=2.9 kpc and dereddened formation rate 22 Msolar per year. Based on kinematics we find that these are dynamically distinguishable, classify them as either merger...
Most massive galaxies contain supermassive black holes (SMBHs) in their cores. When merge, gas is driven to nuclear regions and can accrete onto the central hole. Thus one expects see dual AGN a fraction of galaxy mergers. Candidates for containing have been identified by presence double-peaked narrow [O III] emission lines high spatial resolution images close pairs. Spatially-resolved spectroscopy needed confirm these pairs as systems with spatially-separated double SMBHs. With Keck 2 Laser...
Quasar-driven outflows must have made their most significant impact on galaxy formation during the epoch when massive galaxies were forming rapidly. To study of quasar feedback we conducted rest-frame optical integral field spectrograph (IFS) observations three extremely red quasars (ERQs) and one type-2 at $z=2-3$, obtained with NIFS OSIRIS instruments Gemini North W. M. Keck Observatory assistance laser-guided adaptive optics. We use kinematics morphologies [OIII] 5007\AA H$\alpha$ 6563\AA...
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...
We present commissioning data from the OSIRIS integral field spectrograph (IFS) on Keck II 10 m telescope that demonstrate utility of adaptive optics IFS spectroscopy in studying faint close-in sub-stellar companions haloes bright stars. Our R~2000 J- and H-band spectra companion to 1-10 Myr-old GQ Lup complement existing K-band photometry, improve original estimate its spectral type. find B is somewhat hotter (M6-L0) than reported discovery paper by Neuhauser collaborators (M9-L4), mainly...
We present 0.1" resolution near-infrared integral field spectroscopy of Halpha in a z=1.4781 star forming galaxy, Q2343-BM133. These observations were obtained with OSIRIS (OH Suppressing Infra-Red Imaging Spectrograph) using the W.M. Keck Observatory Laser Guide Star Adaptive Optics system. emission is resolved over 0.8" (6.8 kpc) x 0.5" (4.3 region spatial resolution. find global flux 4.2+/-0.6x10^{-16} ergs s^{-1} cm^{-2}, and detect spatially velocity gradient ~134 km across galaxy...
We present [O iii 5007 Å] observations of the star-forming galaxy (SFG) HDF-BMZ1299 (z = 1.598) using Keck Observatory's adaptive optics system with near-infrared integral field spectrograph OSIRIS. Using previous Hα and [N ii] measurements same source, we are able for first time to use spatially resolved place a high-redshift galaxy's substructure on traditional H ii diagnostic diagram. find that HDF-BMZ1299's concentrated nebular ratios in central ∼1.5 kpc (02) best explained by presence...
IRIS is a near-infrared (0.84 to 2.4 micron) integral field spectrograph and wide-field imager being developed for first light with the Thirty Meter Telescope (TMT). It mounts advanced adaptive optics (AO) system NFIRAOS has integrated on-instrument wavefront sensors (OIWFS) achieve diffraction-limited spatial resolution at wavelengths longer than 1 μm. With moderate spectral (R ~ 4000 – 8,000) large bandpass over continuous of view, will open new opportunities in virtually every area...
Lick Observatory's Optical SETI (search for extraterrestrial intelligence) program has been in regular operation 4.5 years. We have observed 4,605 stars of spectral types F–M within 200 light-years Earth. Occasionally, we appended objects special interest, such as with known planetary systems. 14 candidate signals ("triple coincidences"), all but one which are explained by transient local difficulties. Additional observations the remaining failed to confirm arriving pulse events. now plan...
Deep Keck/NIRC2 HK'L' observations of the Arches cluster near Galactic center reveal a significant population near-infrared excess sources. We combine L'-band with K'-band proper motions, to confirm membership sources in starburst for first time. The robust removal field contamination provides reliable disk fraction down our completeness limit H=19 mag, or about 5 Msun at distance Arches. Of 24 identified K'-L' > 2.0 21 have motion measurements, all which are members cluster. VLT/SINFONI...
We present high angular resolution multi-wavelength data of the 3C 298 radio-loud quasar host galaxy (z=1.439) taken using W.M. Keck Observatory OSIRIS integral field spectrograph with adaptive optics, Atacama Large Millimeter/submillimeter Array (ALMA), Hubble Space Telescope (HST) WFC3, and Very (VLA). Extended emission is detected in rest-frame optical nebular lines H$\beta$, [OIII], H$\alpha$, [NII], [SII], as well molecular CO (J=3-2) (J=5-4). Along path 298's relativistic jets we...
We present results from IROCKS (Intermediate Redshift OSIRIS Chemo-Kinematic Survey) for sixteen z~1 and one z~1.4 star-forming galaxies. All galaxies were observed with the laser guide star adaptive optics system at Keck Observatory. use rest-frame nebular Ha emission lines to trace morphologies kinematics of ionized gas in on sub-kiloparsec physical scales. observe elevated velocity dispersions (sigma > 50 km/s) seen z 1.5 persist integrated Using an inclined disk model ratio v/sigma, we...