Seminario: Mario Guarcello (INAF), ore 15
Oct 12 @ 15:00 – 16:30

Speaker: Mario Guarcello (INAF)

Titolo: “EWOCS: status of the project.”

Abstract: “The EWOCS project has the objective of studying star and planet formation, and early stellar evolution, in very young massive clusters (VYMCs). With a mass in excess of 10^4 solar masses, the very few VYMCs known in the Milky Way represent the most accessible examples of starburst regions, which are very rare in our Galaxy today, but common in galaxies experiencing epochs of intense star formation. These regions are characterized by very high stellar density, and they are dominated by a rich and compact ensemble of massive stars that produce an environment dominated by energetic radiation and particles. With a distance of 3.87 kpc and 4.5 kpc, respectively, the Westerlund 1 and 2 clusters are the closest VYMCs to the Sun, and thus the best targets to study how stars and planets form in the most energetic star forming environment known. In this talk, I will present the status and the preliminary results of the EWOCS project, which is mainly based on a 1Msec Chandra/ACIS-I Large Project and a cycle 1 JWST observation of Westerlund 1, a cycle 2 JWST observation of Westerlund 2, and other data at high spatial resolution of the two clusters.”

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Seminario: Maria Kopsacheili (ICE-CSIC), Aula ore 15
Oct 18 @ 15:00 – 16:30

Speaker: Maria Kopsacheili (ICE-CSIC)
Titolo: New larger sample of Supernova Remnants in NGC 7793, using MUSE IFS.
Abstract: Study of Supernova Remnant (SNR) demographics and their physical properties (density, temperature, shock velocities) is very important in order to understand their role in galaxies. Many photometric and spectroscopic studies of SNRs have been carried out in our Galaxy but also in extragalactic environments. The most common means for the SNR identification in the optical regime, is the use of the flux ratio of the [S II] (λλ6717, 6731) to Hα (λ6563) emission lines. However, this diagnostic is biased against low excitation SNRs. For this reason, we have developed new diagnostics that combine 2 and 3 emission line ratios along with a Support Vector Machine model, that efficiently differentiate SNRs from HII regions. These diagnostics recover up to 35% of the SNRs that we miss using the traditional diagnostic tool, which is very important in order to obtain more complete samples of SNRs (i.e. SNRs of different physical properties) and consequently to more efficiently explore the feedback processes to the host galaxy. We present the application of these diagnostics on Integral Field Unit (IFU) data of the galaxy NGC 7793. We identify new SNR populations, we construct the distributions of their physical properties and their luminosity functions. Finally, we explore possible correlations between properties of SNRs and those of their environment.

Seminario: Emanuele Greco (INAF), Aula ore 16
Nov 9 @ 16:00 – 17:00

Speaker: Emanuele Greco (INAF)
Titolo: Jitter radiation as an alternative for the nonthermal filaments in Supernova Remnants
Abstract: Synchrotron radiation from relativistic electrons is usually invoked as the responsible for the nonthermal emission observed in Supernova Remnants (SNRs). Diffusive shock acceleration (DSA) is the most popular mechanism to explain the process of particles acceleration and within its framework a crucial role is played by the turbulent magnetic-field. However, the standard models commonly used to fit X-ray synchrotron emission do not take into account the effects of turbulence in the shape of the resulting photon spectra. An alternative mechanism that properly includes such effects is the jitter radiation, that provides for an additional power-law beyond the classical synchrotron cutoff. In this talk, i will show the results of applying the jitter spectral model to various X-ray observations of Cassiopeia A and found that it describes the X-ray soft-to-hard range better than any of the standard cutoff models. I will also show what relevant turbulence and electrons’ parameters can be measured from the spectra in the jitter radiation framework.

Seminario: Kevin France (University of Colorado at Boulder), Aula ore 12
Dec 1 @ 12:00 – 13:00

Speaker: Kevin France (University of Colorado at Boulder)

Title:  Exploring Extreme Exoplanets and Stellar Activity with Small Satellite Missions

Abstract: Atmospheric escape is a process that affects the structure, composition, and evolution of many planets.  Atmospheric escape rates depend critically on the extreme-ultraviolet (EUV) and far-ultraviolet (FUV) photon fluxes from the host star.  Owing to high levels of EUV and FUV irradiance from their nearby parent stars, the signatures of rapid atmospheric escape are detectable on close-in, gaseous exoplanets transiting bright stars.  In this talk, I will present current and future small satellite missions designed to directly observe atmospheric escape from exoplanets and to investigate the EUV luminosity and energy partition of EUV flares on nearby stars. The majority of the talk will focus on the Colorado Ultraviolet Transit Experiment (CUTE), a 6U CubeSat mission designed to take advantage of the near-ultraviolet (250 – 330 nm) stellar brightness distribution to conduct novel observations of the extended atmospheres of nearby close-in planets.  CUTE is NASA’s first dedicated exoplanet spectroscopy mission and has collected 6 – 11 transits of each of seven short-period exoplanets.  I will present an overview of the CUTE mission, including its development path and on-orbit observations of excess NUV absorption on ultra-hot Jupiters.  I will conclude the talk by describing the upcoming Monitoring Activity from Nearby sTars with uv Imaging and Spectroscopy (MANTIS) mission, a 12U CubeSat that will make simultaneous observations of nearby stars in four spectral bands from the EUV through the optical (~10 – 1000 nm).  MANTIS will conduct two surveys over its planned two-year mission lifetime: deep EUV observations of nearby stars and contemporaneous stellar characterization data in support of James Webb Space Telescope exoplanet spectroscopy observations.

Dec 4 @ 15:30 – 16:30
Incontro di A.Comastri con il personale OAPa
Dec 6 @ 11:00 – 13:00