Research
In general terms, I am interested in compact objects (black holes and neutron stars), and the electromagnetic signatures associated with them, with no preference for wavelength or object mass. More recently, multimessenger astronomy sparked my interest in connecting gravitational waves with their electromagnetic counterparts.
Gamma-ray bursts (GRB) in active galactic nuclei disks (AGN)
AGN harbor a population of stars and compact objects that are the perfect candidates to source GRBs. Yet, we haven't been able to unequivocally detect them. How to explain this apparent contradiction? In this ongoing project, we already found some very interesting features that a GRB should have if it occurs in an AGN disk, such as a hard-soft evolution, potentially longer duration, and more energetic than those in lower-density environments.
Magnetars as GRB engines
The electromagnetic counterparts to GW170817 raised some questions about the engine powering the associated gamma-ray burst, which prompted researchers to ask whether that engine could be a neutron star prior to its final collapse into a black hole. I ran a few simulations where we found that, although the jets did not attain the required speed for a GRB, microphysics effects such as neutrino pair annihilation could change this scenario.
Jet efficiencies and spins of jetted quasars
Using a sample of 152 flat-spectrum radio quasars (FSRQs) -- a class of blazars --, we estimated their jet production efficiency, and we found a mean value η ~ 0.1. We used these values as an input to calculate the black hole spins using a theoretical model taken from general relativistic radiative MHD simulations (GRRMHD) of thin accretion disks, and found an average lower limit of a = 0.59. Our results show compatibility with spins obtained from models of supermassive black hole evolution through mergers. We also found a moderate correlation between the BH mass and the gamma-ray luminosity, suggesting that Lγ can be used as an estimator of the BH mass in FSRQs.
This work provides a proof of concept for future methods aiming at obtaining the spins of jetted black holes by means of their gamma-ray luminosity. It is currently being extended to BL Lacs which, unlike FSRQs, are better described by geometrically thicker, radiatively inefficient accretion flows.