A5087925506- Gamma-ray bursts and supernovae
- SAS software applications and methods
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Astrophysics and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Adaptive optics and wavefront sensing
- Optical Systems and Laser Technology
- Particle Detector Development and Performance
- Solar and Space Plasma Dynamics
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- Minerals Flotation and Separation Techniques
- Dark Matter and Cosmic Phenomena
- History and Developments in Astronomy
- Geochemistry and Geologic Mapping
- Atmospheric Ozone and Climate
- Computational Physics and Python Applications
- Microbial Metabolites in Food Biotechnology
- Galaxies: Formation, Evolution, Phenomena
- Spectroscopy Techniques in Biomedical and Chemical Research
Monash University
2017-2024
CEA Paris-Saclay
2023
Université Paris-Saclay
2023
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2023
ETH Zurich
2023
University of Würzburg
2023
École Polytechnique
2023
Centre National de la Recherche Scientifique
2023
Laboratoire Leprince-Ringuet
2023
Deutsches Elektronen-Synchrotron DESY
2023
Abstract We report the discovery and monitoring of near-infrared counterpart (AT2017gfo) a binary neutron-star merger event detected as gravitational wave source by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo (GW170817) short gamma-ray burst Fermi Gamma-ray Burst Monitor (GBM) Integral SPI-ACS (GRB 170817A). The evolution transient light is consistent with predictions for behavior “kilonova/macronova” powered radioactive decay massive neutron-rich nuclides...
We present measured scattering matrices as functions of the angle in range 5°–173° and at wavelengths 441.6 nm 632.8 for seven distinct irregularly shaped mineral aerosol samples with properties representative aerosols Earth's atmosphere. The samples, i.e., feldspar, red clay, quartz, loess, Pinatubo Lokon volcanic ash, Sahara sand, represent a wide variety particle size (typical diameters between 0.1 100 μm) composition (mainly silicates). investigate effects differences complex refractive...
Variable X-ray and gamma-ray emission is characteristic of the most extreme physical processes in Universe, studying sources these energetic photons has been a major driver astronomy for past 50 years. Here we present multiwavelength observations unique selected transient, discovered by Swift, which was accompanied bright across electromagnetic spectrum, whose properties are unlike any previously observed source. We pinpoint event to center small, star-forming galaxy at redshift z=0.3534....
(Abridged). We present a sample of 77 optical afterglows (OAs) Swift detected GRBs for which spectroscopic follow-up observations have been secured. provide linelists and equivalent widths all lines redward Ly-alpha. discuss to what extent the current bursts with OA spectroscopy is biased subsample GRBs. For that purpose we define an X-ray selected optimal conditions ground-based follow up from period March 2005 September 2008; 146 fulfill our criteria. derive redshift distribution this...
We present observations of the early X-ray emission for a sample 40 gamma-ray bursts (GRBs) obtained using Swift satellite which narrow-field instruments were pointed at burst within 10 minutes trigger. Using data from Burst Alert and X-Ray Telescopes, we show that light curve can be well described by an exponential relaxes into power law, often with flares superimposed. The transition time between law provides physically defined timescale duration. In most breaks to shallower decay first...
We show that all X-ray decay curves of GRBs measured by Swift can be fitted using one or two components both which have exactly the same functional form comprised an early falling exponential phase followed a power law decay. The 1st component contains prompt gamma-ray emission and initial 2nd appears later, has much longer duration is present for ~80% GRBs. It most likely arises from external shock eventually develops into afterglow. In remaining ~20% fades more slowly than dominates at...
We present observations of GRB 060124, the first event for which both prompt and afterglow emission could be observed simultaneously in their entirety by three Swift instruments. Indeed, Swift-BAT triggered on a precursor ~570s before main burst peak, this allowed to repoint narrow field instruments position ~350s occurred. 060124 also Konus-Wind, harder gamma-ray band (up 2MeV). Thanks these exceptional circumstances, temporal spectral properties can studied optical, X-ray ranges. While...
Aims.We present early optical spectroscopy of the afterglow gamma-ray burst GRB 060206 with aim determining metallicity absorber and physical conditions in circumburst medium. We also discuss how GRBs may be important complementary probes cosmic chemical evolution.
ABSTRACT We report the results of optical follow-up observations 29 gravitational-wave (GW) triggers during first half LIGO–Virgo Collaboration (LVC) O3 run with Gravitational-wave Optical Transient Observer (GOTO) in its prototype 4-telescope configuration (GOTO-4). While no viable electromagnetic (EM) counterpart candidate was identified, we estimate our 3D (volumetric) coverage using test light curves on- and off-axis gamma-ray bursts kilonovae. In cases where source region observable...
ABSTRACT The Gravitational-wave Optical Transient Observer (GOTO) is an array of wide-field optical telescopes, designed to exploit new discoveries from the next generation gravitational wave detectors (LIGO, Virgo, and KAGRA), study rapidly evolving transients, multimessenger opportunities arising neutrino very high energy gamma-ray triggers. In addition a rapid response mode, will also perform sensitive, all-sky transient survey with few day cadence. facility features novel, modular design...
We present photometry and spectroscopy of the afterglow GRB 030323. VLT spectra show damped Lyα (DLA) absorption low- high-ionization lines at a redshift . The inferred neutral hydrogen column density, , is larger than any (GRB- or QSO-) DLA density directly from in absorption. From photometry, we derive conservative upper limit to host-galaxy extinction: mag. iron abundance while metallicity gas as measured sulphur an on H2 molecular fraction In trough, emission line detected, which...
We present B-, V-, RC-, IC-, J-, H-, K-, and K'-band observations of the optical transient (OT) associated with GRB 970228, based on a reanalysis previously used images unpublished data. In order to minimize calibration differences, we have collected analyzed most photometry consistently determined magnitude OT relative set secondary field stars. confirm our earlier finding that early decay light curves (before 1997 March 6) was faster than at intermediate times (between 6 April 7). At late...
Dispersion in the interstellar medium is a well known phenomenon that follows simple relationship, which has been used to predict time delay of dispersed radio pulses since late 1960s. We performed wide-band simultaneous observations four pulsars with LOFAR (at 40-190 MHz), 76-m Lovell Telescope 1400 MHz) and Effelsberg 100-m 8000 test accuracy dispersion law over broad frequency range. In this paper we present results these show accurate better than 1 part 100000 across our observing band....
We present the highest-quality polarisation profiles to date of 16 non-recycled pulsars and four millisecond pulsars, observed below 200 MHz with LOFAR high-band antennas. Based on profiles, we perform an initial investigation expected observational effects resulting from propagation polarised emission in pulsar magnetosphere interstellar medium. The predictions magnetospheric birefringence have been tested using spectra pulse width fractional multifrequency data. derived offer only partial...
Following a BeppoSAX alert and the discovery of OT at SAAO, we observed GRB 990510 with FORS instrument on ESO's VLT Unit 1 (Antu). The burst is unremarkable in gamma rays, but optical first one to show good evidence for jetlike outflow. We report detection significant linear polarization afterglow: it 1.6 ± 0.2% 0.86 days after trigger, 1.81 consistent that same value, much more uncertain. angle constant timescale hours may be over day. conclude intrinsic source due synchrotron nature...
We present Ulysses and NEAR data from the detection of short or intermediate duration (2 s) gamma-ray burst GRB 000301C (2000 March 1.41 UT). The (GRB) was localised by Inter Planetary Network (IPN) RXTE to an area ~50 arcmin2. A fading optical counterpart subsequently discovered with Nordic Optical Telescope (NOT) about 42 h after burst. lies at border between long-soft short-hard classes GRBs. If belongs latter class, this would be first afterglow a UBRI photometry time discovery until 11...
We present time-resolved optical spectroscopy of the afterglows gamma-ray bursts GRB 990510 and 990712. Through identification several absorption lines in first epoch spectrum, we determine redshift for this burst at z >= 1.619. No clear emission are detected. The strength MgI feature is indicative a dense environment, most likely host galaxy 990510. Although extremely faint (V >~ 28), afterglow allows us to probe its interstellar medium - principle measure metallicity. spectrum 990712...
Long-duration gamma-ray bursts (GRBs) accompany the deaths of some massive stars and hence, because are short-lived, a tracer star formation activity. Given that GRBs bright enough to be seen very high redshifts detected even in dusty environments, they should therefore provide powerful probe global history Universe. The potential this approach can investigated via submillimetre (submm) photometry GRB host galaxies. Submm luminosity also correlates with rate, so distribution host-galaxy...