ALTO is a future ground-based very high energy gamma-ray observatory based on water Cherenkov technique, which samples the secondary particles produced in the extensive air showers. This technique also provides long-term, continuous and wide field of view gamma-ray observations. Despite many advantages, the detection technique alone cannot determine the type of primary particle which gives...
An intervening galaxy acts like a gravitational lens and produces multiple images of a single source such as a more remote galaxy. In such a scenario the source, the lens and the observer all have peculiar motions in any random direction in addition to the overall expansion of the universe due to the dark energy. There is a difference in light arriving times from images of a single source,...
Modeling the evolution and mass loss history of rapidly rotating massive stars at low metallicity, we found that chemically homogeneously evolving stars with enhanced rotational mixing could be suitable candidates for both SLSNe in the magnetar-driven scenario and for lGRBs in the collapsar scenario. They retain a high angular momentum in their cores, enough to power these types of explosions,...
The characteristics of the initial magnetic field present in a supernova progenitor prior to collapse and the dynamics of the field amplification due to different dynamo mechanisms (such as MRI, convective motions, etc.) are to this date quite uncertain.
We investigate the effects of multipolar magnetic field topologies of different radial extents on the dynamics of core-collapse supernovae...
In the last years, the improvement of performances of high-energy instruments, both from Earth and Space, has provided a great amount of data relating to Cosmic-Rays (CRs). In particular, in the gamma-ray band, we had the first evidence of CR energization at the Supernova Remnant (SNR) shocks. Several models were developed, assuming that the emission was due to freshly accelerated CRs, in...
An estimate of the jet inclination relative to the accreting black hole's spin can be useful to probe the jet triggering mechanism and the disc-jet coupling. Tidal Disruption Event (TDE) of a star by a supermassive spinning black hole provides a unique astrophysical laboratory to study the jet direction through the possibility of jet precession, induced by the Lense-Thirring precession of the...
The Cherenkov Telescope Array (CTA) project is a next generation observatory for Very-High Energy gamma-ray astronomy. Two sites, in the northern and in the southern emisphere, have already been officially announced by the CTA consortium and will constitute the world largest detector for gamma rays. To push the energy sensitivity in the range of hundreds of TeV, about 70 small-sized telescopes...
We set up the telescope on the road towards the villa
The very bright transient MAXI J1348-630 was discovered in X-rays by MAXI in January 2019 and was then detected also in radio and optical. Immediately after its discovery, it was classified as a black hole candidate based on its X-ray behaviour.
We present an intense radio monitoring of the transient at 1.284 GHz with the new MeerKAT radio interferometer (64 antennas) located in the Karoo...
- Some initial thoughts on the whole process
- Strategy/resources
- Different kinds of positions and other general advice for job hunting strategy
- How to write a good application & deal with letters of recommendation
- Group discussion (the most important part!)
We meet at 2 pm down at the insitute. Then the bus passes by Cargese and you can enter also on the square in front of the Spar supermarket around 2:15 pm.
It has recently been pointed out that ultra-long gamma-ray bursts (ULGRBs), with very atypical durations of more than 1000 seconds, could form a new class of GRBs (Levan+13). ULGRBs could have a different progenitor than standard GRBs and be produced by the core collapse of a low metallicity supergiant blue star (Gendre+13) or the birth of a magnetar following the collapse of a massive star...
In this talk, I will present detailed photoionization models of well-aligned optically thin doubly ionized carbon (C III) absorption components at 2.1 ≤ z ≤ 3.4. Our inferred density and overdensity (∆) favor the absorption originating from gas associated with circumgalactic medium and probably not in hydrostatic equilibrium. We discuss statistically significant redshift evolution of our...
Type Ia Supernovae (SNe Ia) have been studied for many years as standardisable candles for cosmological distance measurement. In addition, these objects have shown to be standard candles in the Infrared (IR), where they are less affected by extinction, probing to be exceptional for cosmology. With the large number of on-going (e.g., ZTF, ATLAS, VEILS) and future surveys (e.g., LSST), both in...
We try to identify the nature of high redshift long Gamma-Ray Bursts (LGRBs) host galaxies by comparing the observed abundance ratios in the interstellar medium with detailed chemical evolution models accounting for the presence of dust. What we have done is to compare abundance data from LGRB afterglow spectra to abundance patterns as predicted by our models for different galaxy types...
The magnetorotational instability (MRI) is considered to be a promising mechanism to amplify the magnetic field in fast-rotating protoneutron stars. Many local studies have proven that the magnetic field could be amplified on small scales. But to explain the dipolar magnetic field strength of the magnetars (10¹⁴-10¹⁵ G), a large scale magnetic field needs to be generated by the MRI. To study...
The acceleration site for UHECR is still an open question despite extended research and GRBs are considered one of the most promising source candidates. Under the likely assumption that electrons are also accelerated at the UHECR acceleration site, synchrotron emission from these co-accelerated electrons is inevitable. We characterize this synchrotron emission and compare it to observed GRB...
