A5069878085- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Galaxies: Formation, Evolution, Phenomena
- Pulsars and Gravitational Waves Research
- Atmospheric Ozone and Climate
- Geophysics and Gravity Measurements
- Solar and Space Plasma Dynamics
- Molecular Spectroscopy and Structure
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
- Spectroscopy and Laser Applications
- History and Developments in Astronomy
- Particle accelerators and beam dynamics
- Superconducting and THz Device Technology
- Advanced Frequency and Time Standards
- Calibration and Measurement Techniques
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
Harvard University
2012-2025
Center for Astrophysics Harvard & Smithsonian
2015-2024
Woodwell Climate Research Center
2019-2024
Royal Darwin Hospital
2022-2024
University of Nottingham
2023
Technical University of Denmark
2023
Harvard University Press
1988-2022
STMicroelectronics (France)
2021
Pacific Northwest National Laboratory
2020
Combat Capabilities Development Command Soldier Center
2015
Abstract This study examines whether the cognitive and affective components of self-reflection can be dissociated using functional magnetic resonance imaging. Using a simple paradigm in which subjects judged personal relevance personality characteristics that were either favorable (e.g., “honest”) or unfavorable “lazy”, we found distinct neural circuits adjacent regions prefrontal cortex subserve emotional aspects self-reflection. The medial responded only to material was self-descriptive,...
The Submillimeter Array, a collaborative project of the Smithsonian Astrophysical Observatory and Academia Sinica Institute Astronomy Astrophysics, has begun operation on Mauna Kea in Hawaii. array comprises total eight 6 m telescopes, which will cover frequency range 180-900 GHz. All telescopes have been deployed are operational. First scientific results utilizing three receiver bands at 230, 345, 690 GHz obtained presented accompanying Letters.
Approximately 10% of active galactic nuclei exhibit relativistic jets, which are powered by accretion matter onto super massive black holes. While the measured width profiles such jets on large scales agree with theories magnetic collimation, predicted structure disk at jet launch point has not been detected. We report radio interferometry observations 1.3mm wavelength elliptical galaxy M87 that spatially resolve base in this source. The derived size 5.5 +/- 0.4 Schwarzschild radii is...
The results of a morphometric study selected human vertebrae undertaken to provide data for implant design are presented in this report. Twenty-seven dimensions were measured from thoracic (T2, T7, T12) and lumbar (L1–L5) using prepared spinal columns 30 skeletons belonging the Hamann-Todd Osteological Collection. Maximum minimum pedicle indicated that pedicles less symmetric cephalad than they caudal. Vertebral body height increases caudally except posteriorly where, after an initial...
view Abstract Citations (450) References (59) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Proper motions and distances of H2O maser sources. I. The outflow in Orion-KL. Genzel, R. ; Reid, M. J. Moran, Downes, D. measurement relative proper features at 22 GHz with VLBI methods is reported. In the source Orion-KL, transverse are typically a few milli-arcsec per year; these interpreted as kinematic compact cloudlets masing gas. data from Orion show...
We report a new geometric maser distance estimate to the active galaxy NGC 4258. The data for model are line-of-sight (LOS) velocities and sky positions from 18 epochs of very long baseline interferometry observations, LOS accelerations measured 10 yr monitoring program 22 GHz emission includes both disk warping confocal elliptical orbits with differential precession. 4258 is 7.60 ± 0.17 0.15 Mpc, 3% uncertainty including formal fitting systematic terms. resulting Hubble constant, based on...
A black hole image contains a series of increasingly narrow rings measurable with progressively longer interferometers.
Magnetic fields near the event horizon Astronomers have long sought to examine a black hole's horizon—the boundary around hole within which nothing can escape. Johnson et al. used sophisticated interferometry techniques combine data from millimeter-wavelength telescopes world. They measured polarization just outside of Sgr A*, supermassive at center our galaxy, Milky Way. The is signature ordered magnetic generated in accretion disk hole. results help explain how holes accrete gas and launch...
We present the first VLBI maps of H2O maser emission (lambda 1.3cm) in nucleus Circinus Galaxy, constructed from data obtained with Australia Telescope Long Baseline Array. The traces a warped, edge-on accretion disk between radii 0.11+/-0.02 and ~0.40 pc, as well wide-angle outflow that extends up to ~1 pc estimated center. rotation is close Keplerian (v varies 1/sqrt(r)), maximum detected speed 260 km/s, inferred central mass 1.7+/-0.3 x 10^6 solar masses. outflowing masers are irregularly...
view Abstract Citations (222) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Detection of a Subparsec Diameter Disk in the Nucleus NGC 4258 Greenhill, L. J. ; Jiang, D. R. Moran, M. Reid, Lo, K. Y. Claussen, We present first VLBI synthesis map luminous H2O maser nucleus (M106). The spectral features masers near systemic velocity, i.e., between 455 and 528 km s-1, are distributed along an almost east-west line sky (83±2 east north), subtending...
view Abstract Citations (237) References (16) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Distance to the Center of Galaxy: H 2O Maser Proper Motions in Sagittarius B2(N) Reid, M. J. ; Schneps, H. Moran, Gwinn, C. R. Genzel, Downes, D. Roennaeng, B. authors measured proper motions many H2O maser spots associated with star-forming region, Sgr B2(N), which lies close Galactic Center. They used five VLBI observations spanning 1.5 yr and achieved relative...
The millimeter/submillimeter wavelength polarization of Sgr A* is known to be variable in both magnitude and position angle on timescales down a few hours. unstable has prevented measurements made at different frequencies epochs from yielding convincing Faraday rotation this source. Here we present observations with the Submillimeter Array polarimeter 227 343 GHz sufficient sensitivity determine measure each band without comparing angles measured separate epochs. We find 10-epoch mean (-5.6...
My life has been an interesting voyage. I became astronomer because could not imagine living on Earth and trying to understand how the Universe works. scientific career revolved around observing motions of stars within galaxies ...Read More
Energetic flares are observed in the Galactic supermassive black hole Sagittarius A* from radio to X-ray wavelengths. On a few occasions, simultaneous have been detected IR and observations, but clear counterparts at longer wavelengths not seen. We present flare over several hours on 2006 July 17 with Chandra X-Ray Observatory, Keck II telescope, Caltech Submillimeter Array. All telescopes strong events, submillimeter peak is found occur nearly 100 minutes after peak. polarization data show...
Using the Submillimeter Array, we have made first high angular resolution measurements of linear polarization Sagittarius A* at submillimeter wavelengths, and detection intra-day variability in its polarization. We detected 340 GHz (880um) several epochs. At typical 1.4"x2.2", expected contamination from surrounding (partially polarized) dust emission is negligible. found that both fraction position angle are variable, with dropping 8.5% to 2.3% over three days. This significant measurement...
view Abstract Citations (208) References (42) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Distance and Kinematics of the W49N H 2O Maser Outflow Gwinn, C. R. ; Moran, J. M. Reid, Study motions 105 H2O maser features clustered around a newly formed star in yields kinematics gas flow, distance to source, spatial scale Milky Way. It is found that outflow bipolar, with an opening angle about 60 deg inclination 40 line sight. The expansion has constant...
Sagittarius A*, the ~4 x 10^6 solar mass black hole candidate at Galactic Center, can be studied on Schwarzschild radius scales with (sub)millimeter wavelength Very Long Baseline Interferometry (VLBI). We report 1.3 mm observations of Sgr A* using a VLBI array consisting JCMT Mauna Kea, ARO/SMT Mt. Graham in Arizona, and two telescopes CARMA Cedar Flat California. Both quasar calibrator 1924-292 were observed over three consecutive nights, both sources clearly detected all baselines. For...