A5063513861- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Radio Astronomy Observations and Technology
- Molecular Spectroscopy and Structure
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Superconducting and THz Device Technology
- Astronomical Observations and Instrumentation
- Atmospheric Ozone and Climate
- Galaxies: Formation, Evolution, Phenomena
- Retinal Imaging and Analysis
- Scientific Research and Discoveries
- Retinal Diseases and Treatments
- Financial Markets and Investment Strategies
- Spectroscopy and Laser Applications
- Housing Market and Economics
- Antenna Design and Optimization
- Ionosphere and magnetosphere dynamics
- Particle Accelerators and Free-Electron Lasers
- Corporate Finance and Governance
- Financial Literacy, Pension, Retirement Analysis
Central Florida Neurosurgery Institute
2025
Harvard University
2011-2024
Center for Astrophysics Harvard & Smithsonian
2015-2024
Massachusetts Eye and Ear Infirmary
2022-2024
University College London
2024
University of Miami
2017-2024
East Kent Hospitals University NHS Foundation Trust
2024
Atrium Health Wake Forest Baptist
2022
Henry Ford Health System
2022
Wayne State University
2022
The next-generation Event Horizon Telescope (ngEHT) will be a significant enhancement of the (EHT) array, with ∼10 new antennas and instrumental upgrades existing antennas. increased uv-coverage, sensitivity, frequency coverage allow wide range science opportunities to explored. ngEHT Analysis Challenges have been launched inform development array design, objectives, analysis pathways. For each challenge, synthetic EHT datasets are generated from theoretical source models released challenge...
We describe the process to design, architect, and implement a transformative enhancement of Event Horizon Telescope (EHT). This program—the next-generation (ngEHT)—will form networked global array radio dishes capable making high-fidelity real-time movies supermassive black holes (SMBH) their emanating jets. builds upon EHT principally by deploying additional modest-diameter optimized geographic locations enhance current mm/submm wavelength Very Long Baseline Interferometric (VLBI) array,...
A simple method is demonstrated for obtaining the thermal diffusivity of solids, by measuring phase lag between a front and rear illumination, at single chopping frequency. The tested using some semiconductor glass samples.
Using high angular resolution (~025-005) Very Large Array (VLA) observations made at 3.6 cm, 1.3 and 7 mm during the period 1991-2004, we report detection of large proper motions in components radio continuum jet associated with high-mass young stellar object (YSO) HW2 star-forming region Cepheus A. The relative observed for two main outflow, moving away from central source nearly opposite directions, are order 140 mas yr-1, or ~480 km s-1 a distance 725 pc. northeast southwest lobes not...
We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with IRAM 30m radio telescope. Owing to close coordination laboratory experiments astrophysics, 112 lines have now been detected carbon-rich star CWLeo. The derived frequencies yield improved rotational centrifugal distortion constants up sixth order. From line profiles interferometric maps Submillimeter Array, bulk SiCSi emis- sion arises region 6 arcseconds radius. abundance is...
Phosphorus-bearing compounds have only been studied in the circumstellar environments (CSEs) of asymptotic giant branch (AGB) star IRC +10216 and protoplanetary nebula CRL 2688, both C-rich objects, O-rich red supergiant VY CMa. The current chemical models cannot reproduce high abundances PO PN derived from observations No reported phosphorus CSEs AGB stars. We aim to set observational constraints on phosphorous chemistry stars, by focussing Mira-type variable IK Tau. Using IRAM 30m...
We present SubMillimeter-Array observations of a Keplerian disk around the Class I protobinary system L1551 NE in 335 GHz continuum emission and submillimeter line 13CO (J=3-2) C18O at resolution ~120 x 80 AU. The 335-GHz dust-continuum image shows strong central peak closely coincident with binary protostars likely corresponding to circumstellar disks, surrounded by ~600 300 AU feature elongated approximately perpendicular [Fe II] jet from southern protostellar component suggestive...
Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational modeling study the C-star envelope IRC +10216, where polymerization acetylene hydrogen cyanide induced by ultraviolet photons can drive linear increasing length. used ALMA to map emission λ 3 mm rotational lines hydrocarbon radicals C2H, C4H, C6H, CN-containing species CN, C3N, HC3N, HC5N...
We present Very Long Baseline Array proper-motion measurements of water masers toward two young stellar objects (YSOs) the W75 N star-forming region. find that these are remarkable for having a similar spectral type, being separated by 07 (corresponding to 1400 AU), and sharing same environment, but with strikingly different outflow ejection geometry. One source has collimated, jetlike at 2000 AU scale, while other shell 160 scale expanding in multiple directions respect central compact...
We present five epochs of VLBI water maser observations around the massive protostar Cepheus A HW2 with 0.4 mas (0.3 AU) resolution. The main goal these was to follow evolution remarkable linear/arcuate structures found in earlier observations. Comparing data our new observation those observed years before, we find that at "large" scales > 1" (700 regions emission persist, implying both surrounding medium and exciting sources masers have been relatively stable during time span. However,...
We report a spectral-line survey of the extreme carbon star IRC+10216 carried out between 293.9 and 354.8 GHz with Submillimeter Array. A total 442 lines were detected, more than 200 for first time; 149 are unassigned. Maps at an angular resolution ~3" obtained each line. substantial new population narrow expansion velocity ~4 km/s (i.e. ~ 30% terminal velocity) was detected. Most these attributed to rotational transitions within vibrationally excited states, emitted from energy levels above...
Context. Dust is efficiently produced by cool giant stars, but the condensation of inorganic dust poorly understood. Observations key aluminum bearing molecules around evolved stars has enabled us to investigate nucleation alumina (Al2O3) in gas.
During their late pulsating phase, AGB stars expel most of mass in the form massive dusty envelopes, an event that largely controls composition interstellar matter. The however, are distant and opaque to visible NIR radiation: structure remains poorly known mass-loss process understood. Millimeter-wave interferometry, which combines advantages longer wavelength, high angular resolution very spectral is optimal investigative tool for this purpose. Mm waves pass through dust with almost no...
A 32[Formula: see text]GHz bandwidth VLBI capable correlator and phased array has been designed deployed a at the Smithsonian Astrophysical Observatory’s Submillimeter Array (SMA). The SMA Wideband Astronomical ROACH2 Machine (SWARM) integrates two instruments: with 140[Formula: text]kHz spectral resolution across its full band, used for connected interferometric observations, summer when participates as station in Event Horizon Telescope (EHT) very long baseline interferometry (VLBI) array....
High-resolution imaging of supermassive black holes is now possible, with new applications to testing general relativity and horizon-scale accretion relativistic jet formation processes. Over the coming decade, EHT will propose add strategically placed VLBI elements operating at 1.3mm 0.87mm wavelength. In parallel, development next-generation backend instrumentation, coupled high throughput correlation architectures, boost sensitivity, allowing stations be modest collecting area while still...
The first very long baseline interferometry (VLBI) detections at 870$\mu$m wavelength (345$\,$GHz frequency) are reported, achieving the highest diffraction-limited angular resolution yet obtained from surface of Earth, and highest-frequency example VLBI technique to date. These include strong for multiple sources observed on inter-continental baselines between telescopes in Chile, Hawaii, Spain, during observations October 2018. longest-baseline approach 11$\,$G$\lambda$ corresponding an...
Background and Objective To report quantitative vascular metrics of healthy control eyes children, using expanded field swept-source optical coherence tomography angiography (SS-OCTA), as a baseline to compare with pathologic findings. Patients Methods A cross-sectional observational study children (age 6 18) who were imaged on the PLEX Elite 9000 instrument at 100-kHz scanning rate 3 × 3-mm, 6-mm, 12 12-mm protocols centered fovea (2019 2023). Scans uploaded ARI Network (Zeiss Portal v5.4)...
We report the first detection of pure rotational transitions TiO and TiO_2 at (sub-)millimeter wavelengths towards red supergiant VY CMa. A temperature, T_rot, about 250 K was derived for TiO_2. Although T_rot not well constrained TiO, it is likely somewhat higher than that The Ti oxides confirms they are formed in circumstellar envelopes cool oxygen-rich stars may be "seeds" inorganic-dust formation, but alternative explanations our observation cooler regions envelope cannot ruled out this...