P. J. Meintjes
A5063745055- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Dark Matter and Cosmic Phenomena
- Stellar, planetary, and galactic studies
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Sensor Technology
- Atomic and Subatomic Physics Research
- Superconducting Materials and Applications
- SAS software applications and methods
- Magnetic confinement fusion research
University of the Free State
2015-2024
South African Radio Astronomy Observatory
2016-2024
Consejo Superior de Investigaciones Científicas
2024
Universidad de Málaga
2024
Université Paris-Saclay
2021
Institut de Recherche sur les Lois Fondamentales de l'Univers
2021
CEA Paris-Saclay
2021
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2021
University of Namibia
2020-2021
Centre National de la Recherche Scientifique
2021
We present the discovery of a Neptune-mass planet OGLE-2007-BLG-368Lb with planet–star mass ratio q = [9.5 ± 2.1] × 10−5 via gravitational microlensing. The planetary deviation was detected in real-time thanks to high cadence Microlensing Observations Astrophysics survey, light-curve monitoring and intensive follow-up observations. A Bayesian analysis returns stellar distance at Ml 0.64+0.21−0.26 M☉ Dl 5.9+0.9−1.4 kpc, respectively, so separation are Mp 20+7−8 M⊕ 3.3+1.4−0.8 AU,...
We combine all available information to constrain the nature of OGLE-2005-BLG-071Lb, second planet discovered by microlensing and first in a high-magnification event. These include photometric astrometric measurements from Hubble Space Telescope, as well constraints higher order effects extracted ground-based light curve, such microlens parallax, planetary orbital motion finite-source effects. Our primary analysis leads conclusion that host Jovian OGLE-2005-BLG-071Lb is an M dwarf foreground...
Aims. We report the discovery of a planet with high planet-to-star mass ratio in microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over 12-day interval, one longest for any planetary event. The host is an M dwarf, range 0.07 M⊙ < Mhost 0.49 at 90% confidence. planet-star q = 0.0132 ± 0.003 has been measured extremely well, so best-estimated mass, mp 2.6 Jupiter masses median 0.19 M⊙.
We report the discovery of a rapid spindown 33-s rotation period white dwarf in AE Aqr at steady rate 5.64 |$5.64 \times 10^{-14} \text s \enspace s^{-1}$| over baseline least 14.5 yr. The newly derived orbital by Welsh, Horne & Gomer is confirmed, and it shown that secondary star's absorption-line radial velocities provide correct phasing for oscillations if they originate dwarf. amplitude pulse-timing delays, |$a_ {wd} {sin}\enspace i = 2.04\enspace $|, yields mass between 0.9 1.0 M⊙....
Context . Gamma-ray bursts (GRBs) are ideal probes of the Universe at high redshift (ɀ), pinpointing locations earliest star-forming galaxies and providing bright backlights with simple featureless power-law spectra that can be used to spectrally fingerprint intergalactic medium host galaxy during period reionization. Future missions such as Gamow Explorer (hereafter Gamow) being proposed unlock this potential by increasing rate identification high-ɀ (ɀ > 5) GRBs in order rapidly trigger...
Abstract Thanks to the rapidly increasing time-domain facilities, we are entering a golden era of research on gamma-ray bursts (GRBs). In this Letter, report our observations GRB 240529A with Burst Optical Observer and Transient Exploring System, 1.5 m telescope at Observatorio de Sierra Nevada, 2.5 Wide Field Survey Telescope China, Large Binocular Telescope, Telescopio Nazionale Galileo. The prompt emission shows two comparable energetic episodes separated by quiescence time roughly 400 s....
We report multisite observations devoted to the main-sequence δ Scuti star XX Pyx, conducted as 17th run of Delta Network. Over 125 nights a total 550 h usable time-series photometric B- and V-filter data were acquired involving both photoelectric CCD measurements at eight observatories spread around world, which represents most extensive single for any pulsating other than Sun obtained so far.
ThunderKAT is the image-plane transients programme for MeerKAT. The goal as outlined in 2010, and still today, to find, identify understand high-energy astrophysical processes via their radio emission (often concert with observations at other wavelengths). Through a comprehensive complementary of surveying monitoring Galactic synchrotron (across range compact accretors explosive phenomena) exploring distinct populations extragalactic (microquasars, supernovae possibly yet unknown transient -...
We present the results from a high cadence, multi-wavelength observation campaign of AT 2016jbu (aka Gaia16cfr), an interacting transient. This dataset complements current literature by adding higher cadence as well extended coverage lightcurve evolution and late-time spectroscopic evolution. Photometric reveals that underwent significant photometric variability followed two luminous events, latter which reached absolute magnitude M$_V\sim$-18.5 mag. is similar to transient SN 2009ip whose...
We report UBVRI observations of the optical afterglow gamma-ray burst GRB 021004. observed significant (10-20%) deviations from a power law decay on several time scales, ranging few hours down to 20-30 minutes. also color change starting ~1.5 days after burst, confirming spectroscopic results already reported by Matheson et al. (2002). discuss these in context models that have recently been proposed account for anomalous photometric behavior this event.
view Abstract Citations (79) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS AE Aquarii: an Emitter of Pulsed TeV Gamma Rays Resembling Optical Emission during Flares Meintjes, P. J. ; Raubenheimer, B. C. de Jager, O. Brink, Nel, H. I. North, A. R. van Urk, G. Visser, Extensive optical and VHE data on Aquarii obtained over the last four years are described. The analyzed, it is shown that Aqr shows definite emission patterns flares which may be...
Using data from contemporaneous observations with Chandra and Swift, it is shown that the X-ray emission below 10 keV predominantly thermal, characterized by flares lines dominated soft component. The Swift spectra (EX≤ keV) can be reproduced multicomponent thermal models a time-averaged luminosity of LX∼ 1031 erg s−1. pulsed 33-s confirmed in both sets. epoch pulse maximum white dwarf spin period consistent recently derived ephemeris based upon Suzaku measurements. detected hard component...
ThunderKAT is the image-plane transients programme for MeerKAT. The goal as outlined in 2010, and still today, to find, identify understand high-energy astrophysical processes via their radio emission (often concert with observations at other wavelengths). Through a comprehensive complementary of surveying monitoring Galactic synchrotron (across range compact accretors explosive phenomena) exploring distinct populations extragalactic (microquasars, supernovae possibly yet unknown transient -...
view Abstract Citations (68) References (32) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Simultaneous Optical and TeV Gamma-Ray Observations of the Cataclysmic Variable AE Aquarii Meintjes, P. J. ; de Jager, O. C. Raubenheimer, B. Nel, H. I. North, A. R. Buckley, D. Koen, In this paper we report on findings simultaneous optical gamma-ray observations (eight nights, 32 hr in total) magnetic cataclysmic variable which contains most rapidly spinning white...
The mass function and statistics of binaries provide important diagnostics the star formation process. Despite this importance, at low masses remains poorly known due to observational difficulties caused by faintness objects. Here we report microlensing discovery characterization a binary lens composed very low-mass stars just above hydrogen-burning limit. From combined measurements Einstein radius microlens parallax, measure components $0.10\pm 0.01\ M_\odot$ $0.09\pm M_\odot$. This...
Long gamma-ray bursts are produced during the dramatic deaths of massive stars with very short lifetimes, meaning that they explode close to birth place their progenitors. During a period become most luminous objects observable in Universe, being perfect beacons study high-redshift star-forming regions. To use afterglow GRB 161023A at redshift $z=2.710$ as background source environment explosion and intervening systems along its line-of-sight. r first time, we complement UV/Optical/NIR...
We report a measurement of limb darkening solar-like star in the very high magnification microlensing event MOA 2002-BLG-33. A 15 hour deviation from light curve profile expected for single lens was monitored intensively V and I passbands by five telescopes spanning globe. Our modelling showed to be close binary system whose centre-of-mass passed almost directly front source star. The identified as an F8-G2 main sequence turn-off measured stellar profiles agree with current atmosphere theory...
The gamma-ray binary system PSR B1259−63/LS 2883 consists of a 48 ms pulsar orbiting Be star. is particularly interesting because it the only where nature compact object known. non-thermal radiation from powered by spin-down luminosity and unpulsed originates stand-off shock front which forms between stellar wind. star/optical companion in produces an excess infrared (IR) flux associated circumstellar disc. This IR provides additional photon source for inverse Compton scattering. We discuss...
In this paper, the possibility of periodic pulsar-like gamma-ray emission from white dwarfs in AE Aquarii and AR Scorpii is investigated. We show that dwarf magnetospheres can possibly induce potentials to accelerate charged particles energies excess one tera electronvolt (TeV) with associated through processes such as curvature radiation, inverse Compton, hadronic neutral pion decay. report here pulsed signatures at or close spin period both Fermi-LAT dataset. This may indicate these...
Aims. We investigate constraints on additional planets orbiting the distant M-dwarf star OGLE 2005-BLG-390L, around which photometric microlensing data has revealed existence of sub-Neptune-mass planet 2005–BLG–390Lb. specifically aim to study potential Jovian companions and compare our findings with predictions from core-accretion disc-instability models formation. also obtain an estimate detection probability for sub-Neptune mass similar 2005–BLG–390Lb using a simplified simulation experiment.
We present the analysis result of a gravitational binary-lensing event OGLE-2005-BLG-018. The light curve is characterized by 2 adjacent strong features and single weak feature separated from features. exhibits noticeable deviations best-fit model based on standard binary parameters. To explain deviation, we test models including various higher-order effects motions observer, source, lens. From this, find that it necessary to account for orbital motion lens in describing curve. modeling...
We have studied the long-term (~ years) temporal variability of prototype supersoft X-ray source (SSS) CAL 83 in LMC, using data from MACHO and OGLE projects. The light curve exhibits dramatic brightness changes ~1 mag on timescales ~450 days, spends typically ~200 days optical low state. Combined with archival XMM-Newton observations these represent most extensive X-ray/optical study to date this system, reveal much greater detail that is anti-correlated behaviour. This remarkably similar...