Calendar
Titolo: Modeling the interaction of a Supernova Remnant with the Circumstellar Medium – The case of the gamma-ray bright galactic supernova remnant RX J1713.7-3946
Abstract: SNRs are strongly characterized by their interaction with the circumstellar medium (CSM), often shaped by the mass loss history of the progenitor star, and with the ambient interstellar medium (ISM).
The aim of the thesis is to explore the physics of the interaction of a SNR with the CSM by examining a specific SNR through hydrodynamic (HD) numerical simulations. In particular, I focus on the remarkable Galactic SNR RX J1713.7-3946.
I will expose the results of hydrodynamics simulations regarding the formation of the CSM, the expansion of the SNR through the CSM and finally the interaction of the SNR with a molecular cloud. I will show the results of the synthesis of X-ray thermal emission from the outcome of those simulations.
Finally, I compare the X-ray thermal emission with actual X-ray observations of RX J1713. In particular, I show that the zero age main sequence mass of the progenitor of RX J1713 is of the order of 15 solar masses. Moreover, I derive that the explosion energy of the parent supernova is of the order of 1 FOE, while a highly energetic explosion (≥ 2 FOE) can be excluded. Finally, I obtain a tight constraint on the age of the remnant, which is of ∼ 2150 yr.
Title: Sub-stellar initial mass function of Trumpler 14
Abstract:
Visita Museo + Presentazione in aula di 2 classi (Prima media, 20 pax per gruppo) dall’I.C Tomasi di Lampedusa (Sambuca di Sicilia) Prof.ssa Di Franco
Titolo: Investigating the Solar-Stellar Analogy: The flare star AD Leo compared to our Sun
Speaker: W.M. Joseph (Institut für Astronomie & Astrophysik, Eberhard Karls Universität Tübingen)
Abstract: The solar corona is often invoked as a template for stellar ones, but the significant difference between solar and non-solar instruments and data makes direct comparison between X-ray observations of the Sun, which is usually of the resolved solar disk, and stellar point-source observations almost impossible. In order to overcome this hurdle, the research group at INAF Osservatorio Astronomico di Palermo has devised a method in which solar X-ray data is converted to a format which is virtually identical to that of actual stellar X-ray observations (called the Sun-as-an-Xray-star, SaXS, method; e.g., Peres+2000, ApJ 528).
First applications of the Sun-as-an-Xray-star method have used a grid of synthetic “stellar-like” X-ray spectra based on emission measures for different types of solar coronal structures like background corona, active regions, cores of active regions and flares. The target star’s coronal filling factor with these regions was then found by finding the grid-point closest to the observed X-ray spectrum of the star (e.g., Coffaro+2020). We have now further developed this method into spectral models using XSPEC that correspond to the different solar magnetic structures (background corona, active regions, cores of active regions and flares). Using these models, the hypothetical filling factors of these regions can be recovered.
For the first time, we apply the Sun-as-an-Xray-star method to a star which significantly differs from our Sun, AD Leo, in order to investigate how far the postulated solar-stellar analogy can be stretched. The early-M dwarf AD Leo is the ideal benchmark for stellar activity in the low-mass regime and its influence on planet atmospheres due to its proximity (5 pc) and high activity level, allowing for high-signal X-ray observations. In this project, we aim to reconstruct an X-ray corona of AD Leo, assuming it is covered by solar magnetic structures. We apply the XSPEC implementation of the Sun-as-an-Xray-star method to AD Leo spectra from eROSITA and XMM-Newton, and investigate the results of its application.