Presentation materials
Feature extraction is one of the crucial stages in trying to apply machine learning to tasks on real astronomical data. In particular, when dealing with transients where light-curves are sparsely sampled, with varying numbers of points and in the presence of uncertainties. One of the standard methods to extract features from a light curve is to find the best fit parameter values to a...
SN 2012au is a key intermediate object between Type Ib supernovae (SNe), superluminous SNe and the highly-energetic, hypernovae. This unusual SN had a higher mass loss rate than other hypernovae but likely arose from a progenitor star of about 80 solar masses. These two findings contradict previous theories that more massive stars could not produce such an explosion, suggesting that a...
Observations of supernovae (SNe) within a couple of days post explosion have the potential to probe the physics of their early evolution. This could provide insight into physics of several phenomenon including shock breakout, interactions with circumstellar material, and companion interactions. Unfortunately these early time observations are rare. I will present my work on automating the...
Supernovae (SNe) play an essential role in accounting for the origin of the elements observed in our universe. To translate the information on the ejected elements contained in observed SN-spectra, careful modelling of the SNe is required. In this talk, I will discuss the nebular phase spectra resulting from modelling a set of He-star explosions (progenitors of type Ibc SNe). The set spans a...
On September 22, 2017, the IceCube Neutrino Observatory detected a high-energy neutrino of potential astrophysical origin which was found by follow-up electromagnetic observations to spatially and temporally coincide with the flaring state of a known blazar, TXS 0506+056. Since then, several additional neutrino events have been found in spatial correlation with known highenergy sources....
A Tidal Disruption Event (TDE) occurs when a star gets close enough to a supermassive black hole, such that the tidal forces are able to rip the star apart, causing a multiwavelength transient flare. These events illuminate the complex environments of galactic centers in what may otherwise be quiescent galaxies. TDEs are typically discovered at shorter wavelengths (optical, Xray) but with new...
The Transiting Exoplanet Survey Satellite (TESS) has been conducting a wide-field, space-based survey of the entire night sky to identify transiting exoplanets. Additionally, its large field of view (2304 sq. deg) and continuous, high-cadence, monthlong observations of a given region of the sky lend it well to the discovery and characterization of transients. TESS can work in conjunction with...
Stochastic gravitational-wave backgrounds (SGWB) derive from the superposition of numerous individually unresolved gravitational-wave (GW) signals. In this talk, I will present a detailed modelization of the SGWB from compact binary mergers. I will discuss the use of population synthesis models to estimate the expected rate and properties of binary mergers for different types of compact...
Despite their discovery 50 years ago, emission mecanisms and models of gamma ray bursts (GRBs) are not well constrained by spectrometry alone. Precise polarimetric measurement could bring new insights on the way these transient events are produced. COMCUBE is a project of CubeSat constellation using Compton telescopes to detect polarity of GRB prompt emission from about 100keV up to 1MeV. I...
Gamma-Ray Bursts (GRB) are short (up to few tens of seconds) and intense flashes of gamma-rays, appearing from random directions over the entire sky. These flashes are either created by the collapse of very massive stars (more than 50 times the mass of the Sun), or the merging of two compact objects (e.g. two neutron stars). The event of the 17th August 2017, as the first joint observation of...
The Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a Chinese-French mission dedicated to the study of the transient sky, scheduled for launch in 2024. Its core program focuses on the gamma-ray bursts (GRB) detection thanks to the ECLAIRs telescope and its onboard trigger system. This instrument under French responsibility is a large field of-view coded mask telescope....
The binary neutron star merger gravitational-wave event GW 170817 and the multi-wavelength observations of its off-axis afterglow have allowed to probe the lateral structure of its associated relativistic jet. In addition, several gamma-ray bursts such as GRB 190114C or GRB 221009A (the brightest GRB ever observed) have recently been detected at Very High Energy (VHE, > 1 TeV) and are...
X-ray reverberation is a powerful technique used to measure the black hole in the thin disk system. Recent observation of tidal disruption events shows that X-ray reverberation arising from characteristic Fe Kα photons can also happen in the super-Eddington system. State-of-the-art simulations show that optical and geometrical thick wind can be launched in the super-Eddington accretion. The...
We report on the results obtained by an optical spectroscopy study performed on the black hole transient MAXI J1305−704 during its 2012 outburst. We analysed two observations taken by the Magellan Clay Telescope during two consecutive nights, when the source was in a soft X-ray spectral state. Then, we extracted 12 phase-resolved spectra and performed a spectral fitting of the dominant H-alpha...
My PhD project deals with astrophysical X-ray polarimetry. The state-of-art is the Imaging X-ray Polarimetry Explorer (IXPE), launched on 9 December 2021 (collaboration NASA and ASI) to measure the linear polarization of different astrophysical sources over the photon energy range 2-8 keV. One of the goals of my project is the analysis of IXPE data provided by current observations. In...
