Calvin Sykes
A5044604990- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- History and Developments in Astronomy
- Pulsars and Gravitational Waves Research
- Advanced Semiconductor Detectors and Materials
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
University of Southampton
2023-2024
Durham University
2019
Glowing filaments of the cosmic web Most gas in Universe lies intergalactic medium, where it forms into sheets and web. Clusters galaxies form at intersection these filaments, fed by pulled along them gravity. Although this picture is well established cosmological simulations, has been difficult to demonstrate observationally. Umehata et al. mapped emission from medium an area around that are starting a cluster (see Perspective Hamden). They found arranged whose position velocity correlate...
ABSTRACT The motion of S2, one the stars closest to Galactic Centre, has been measured accurately and used study compact object at centre Milky Way. It is commonly accepted that this a supermassive black hole, but nature its environment open discussion. Here, we investigate possibility dark matter in form an ultralight scalar field ‘cloud’ clusters around Sgr A*. We use available data for S2 perform Markov Chain Monte Carlo analysis find best-fit estimates cloud structure. Our results show...
Context. Since 2019, GRAVITY has provided direct observations of giant planets and brown dwarfs at separations down to 95 mas from the host star. Some these have first confirmation companions previously detected by indirect techniques (astrometry radial velocities). Aims. We want improve observing strategy data reduction in order lower inner working angle dual-field on-axis mode. also determine current limitations instrument when faint with 30–150 range. Methods. To angle, we propose a fiber...
Abstract We resolve the multiple images of binary-lens microlensing event ASASSN-22av using GRAVITY instrument Very Large Telescope Interferometer (VLTI). The light curves show weak perturbations, complicating analysis, but joint modeling with VLTI data breaks several degeneracies, arriving at a strongly favored solution. Thanks to precise measurements angular Einstein radius θ E = 0.724 ± 0.002 mas and microlens parallax, we determine that lens system consists two M dwarfs masses 1 0.258...
Photoheating of the gas in low-mass dark matter (DM) haloes prevents baryons from cooling, leaving free stars. Gas these 'dark' remains exposed to ultraviolet background (UVB), and so is expected emit via fluorescent recombination lines. We present a set radiative transfer simulations, which model as spherical clouds hydrostatic equilibrium with DM halo potential, thermal UVB at redshift z = 0. use simulations predict surface brightnesses |${\mathchoice{{\text{H}}\, {\alpha }}{{\text{H}}\,...
Since 2019, GRAVITY has provided direct observations of giant planets and brown dwarfs at separations down to 95 mas from the host star. Some these have first confirmation companions previously detected by indirect techniques (astrometry radial velocities). We want improve observing strategy data reduction in order lower inner working angle dual-field on-axis mode. also determine current limitations instrument when faint with 30-150 range. To angle, we propose a fiber off-pointing during...
We resolve the multiple images of binary-lens microlensing event ASASSN-22av using GRAVITY instrument Very Large Telescope Interferometer (VLTI). The light curves show weak binary perturbations, complicating analysis, but joint modeling with VLTI data breaks several degeneracies, arriving at a strongly favored solution. Thanks to precise measurements angular Einstein radius \theta_E = 0.726 +/- 0.002 mas and microlens parallax, we determine that lens system consists two M dwarfs masses M_1...
Observational measures of the primordial helium mass fraction, $Y_{\rm P}$, are interest for cosmology and fundamental particle physics. Current obtained from H II regions agree with Standard Model prediction to approximately 1% precision, although these determinations may be affected by systematic uncertainties. This possibility can only tested independently measuring abundance in new ways. Here, we propose a novel method obtain measurement P}$ using hydrogen recombination line emission...