Search Publications
Eclipse mapping of EXO 0748-676: evidence for a massive neutron star
Ingram, Adam; Middleton, Matthew; Knight, Amy H. +1 more
Determining the maximum possible neutron star (NS) mass places limits on the equation of state (EoS) of ultra-dense matter. The mass of NSs in low-mass X-ray binaries can be determined from the binary mass function, providing independent constraints are placed on both the binary inclination and mass ratio. In eclipsing systems, they relate via the…
A new look at the frequency-dependent damping of slow-mode waves in the solar corona
Nakariakov, Valery M.; Kolotkov, Dmitrii Y.
Being directly observed in the Doppler shift and imaging data and indirectly as quasi-periodic pulsations in solar and stellar flares, slow magnetoacoustic waves offer an important seismological tool for probing many vital parameters of the coronal plasma. A recently understood active nature of the solar corona for magnetoacoustic waves, manifeste…
A multiwavelength study of the W33 Main ultracompact HII region
Menten, K. M.; Khan, S.; Wyrowski, F. +7 more
Aims: The dynamics of ionized gas around the W33 Main ultracompact HII region is studied using observations of hydrogen radio recombination lines and a detailed multiwavelength characterization of the massive star-forming region W33 Main is performed.
Methods: We used the Giant Meterwave Radio Telescope (GMRT) to observe the H167α recomb…
A Simple Radial Gradient Filter for Batch-Processing of Coronagraph Images
Pant, Vaibhav; Banerjee, Dipankar; Patel, Ritesh +1 more
Images of the extended solar corona, as observed by different white-light coronagraphs, include the K- and F-corona and suffer from a radial variation in intensity. These images require separation of the two coronal components with some additional image-processing to reduce the intensity gradient and analyse the structures and processes occurring …
OGLE-2018-BLG-0799Lb: a q 2.7 × 10-3 planet with Spitzer parallax
Maoz, Dan; Han, Cheongho; Udalski, Andrzej +73 more
We report the discovery and analysis of a planet in the microlensing event OGLE-2018-BLG-0799. The planetary signal was observed by several ground-based telescopes, and the planet-host mass ratio is q = (2.65 ± 0.16) × 10-3. The ground-based observations yield a constraint on the angular Einstein radius θE, and the microlensi…
Over-expansion of coronal mass ejections modelled using 3D MHD EUHFORIA simulations
Poedts, Stefaan; Scolini, Camilla; Schmieder, Brigitte +5 more
Coronal mass ejections (CMEs) are large scale eruptions observed close to the Sun. They are travelling through the heliosphere and possibly interacting with the Earth environment creating interruptions or even damaging new technology instruments. Most of the time their physical conditions (velocity, density, pressure) are only measured in situ at …
Tracking the 3D evolution of a halo coronal mass ejection using the revised cone model
Zhang, Q. M.
Aims: This paper aims to track the three-dimensional (3D) evolution of a full halo coronal mass ejection (CME) on 2011 June 21.
Methods: The CME results from a nonradial eruption of a filament-carrying flux rope in NOAA active region 11236. The eruption was observed in extreme-ultraviolet (EUV) wavelengths by the extreme-ultraviolet imag…
Looking at the Distant Universe with the MeerKAT Array: Discovery of a Luminous OH Megamaser at z > 0.5
Holwerda, Benne W.; Ravindranath, Swara; Somerville, Rachel S. +65 more
In the local universe, OH megamasers (OHMs) are detected almost exclusively in infrared-luminous galaxies, with a prevalence that increases with IR luminosity, suggesting that they trace gas-rich galaxy mergers. Given the proximity of the rest frequencies of OH and the hyperfine transition of neutral atomic hydrogen (H I), radio surveys to probe t…
TOI-1696: A Nearby M4 Dwarf with a 3 R ⊕ Planet in the Neptunian Desert
Ikuta, Kai; Bieryla, Allyson; Latham, David W. +59 more
We present the discovery and validation of a temperate sub-Neptune around the nearby mid-M dwarf TIC 470381900 (TOI-1696), with a radius of 3.09 ± 0.11 R ⊕ and an orbital period of 2.5 days, using a combination of Transiting Exoplanets Survey Satellite (TESS) and follow-up observations using ground-based telescopes. Joint analysis of mu…
Mass segregation in the hyades cluster
Evans, N. Wyn; Oh, Semyeong
Using the Gaia colour-magnitude diagram, we assign masses to a catalogue of 979 confirmed members of the Hyades cluster and tails. By fitting the cumulative mass profile, stars within the tidal radius have a Plummer-like profile with half-mass radius rh of 5.75 pc. The tails are extended with rh = 69.35 pc and fall off more s…