Calendar

Sep
6
Tue
Seminario: R. Giuffrida (UNIPA)
Sep 6 @ 15:00 – 16:30

Seminario in forma ibrida

Indirizzo Google meet: https://meet.google.com/sxz-cctp-tsc

Speaker: R. Giuffrida (UNIPA)
Titolo: The supernova remnant SN 1006 as a Galactic particle accelerator
Abstract:
The origin of cosmic-rays is an open issue of high-energy astrophysics. Supernova remnants are expected to be the main source of Galactic cosmic rays up to energies of about 3 PeV, provided that they transfer a significant fraction of their kinetic energy to the particles (∼ 10%). In particular, the loss of such a large fraction of energy is predicted to alter the shock dynamics by enhancing the shock compression ratio above the canonical value of 4 (shock modification). The bilateral supernova remnant SN 1006 is an ideal target to study shock modification because of its evolution in a fairly uniform environment. SN 1006 shows bright synchrotron X-ray emission from ultrarelativistic electrons accelerated at the shock front in its northeastern and southwestern limbs. If efficient hadron acceleration occurs in these regions, we should observe shock modification therein. We performed a spatially resolved spectral analysis of Chandra and XMM-Newton observations of SN 1006 by selecting narrow regions between the shock front and the contact discontinuity and measuring the density of the X-ray emitting plasma. Our results show an increase of the compression ratio from the characteristic value of 4, in thermal limb, up to ∼ 7 in nonthermal limbs, i.e. in regions where the ambient magnetic field is almost parallel to the shock velocity. We conclude that an efficient particle acceleration causes shock modification in quasi-parallel shocks in SN 1006. By comparing our results with state-of-the-art models, we find that SN 1006 is transferring a significant fraction of its kinetic energy to hadrons. The inferred values of compression ratios and cosmic ray slopes are consistent with those expected for modified shocks when the effects of the postcursor are included.

Sep
14
Wed
Seminario: Vincenzo Sapienza (UNIPA)
Sep 14 @ 15:00 – 16:30

Seminario in forma ibrida

Indirizzo Google Meet: https://meet.google.com/sxz-cctp-tsc

Speaker: Vincenzo Sapienza (UNIPA)

Titolo: A spatially resolved study of hard X-ray emission in Kepler’s SNR: indications of different regimes of particle acceleration

Abstract:
L’emissione di Sincrotrone nei raggi X proveniente da resti di supernova (SNR) giovani è un potente strumento diagnostico per studiare la popolazione di elettroni altamente energetici accelerati al fronte di shock oltre che per studiare il processo di accelerazione stesso.
In questo lavoro abbiamo eseguito un’analisi spettrale spazialmente risolta di osservazioni NuSTAR e XMM-Newton del giovane SNR di Keplero, con lo scopo di studiare in dettaglio la sua emissione non termica nei raggi X duri.
Gli spettri sono stato analizzati adottando un modello di radiazione di sincrotrone in un regime in cui l’energia massima degli elettroni è limitata dalle perdite radiative, in modo da vincolare la dipendenza dell’energia di cutoff del sincrotrone dalla velocità del fronte di shock.
Abbiamo identificato due diversi regimi di accelerazione di particelle.
A nord, dove lo shock sta interagendo con un mezzo circumstellare denso, abbiamo trovato una accelerazione più efficiente che a sud, dove la velocità del fronte di shock è più alta e non ci sono segni di interazione tra shock e un mezzo circumstellare denso.
I nostri risultati suggeriscono un’efficienza maggiore in regioni dove l’interazione tra shock e mezzo circumstellare genera un campo magnetico turbolento ed amplificato.
Combinando lo spettro nei raggi X duri con osservazioni radio e gamma del SNR di Keplero, abbiamo modellato la distribuzione dell’energia spettrale (SED). Alla luce dei nostri risultati proponiamo che l’emissione gamma osservata sia principalmente adronica (associata a protoni ultrarelativistici), e che origini dalla parte nord del resto.

Sep
15
Thu
Seminario: presentazione della tesi di studenti UNIPA: Tramuto e Caserta
Sep 15 @ 15:00 – 16:30

Speakers1 Alessandro Salvatore Tramuto
Titolo1: Photometric classification of variable young stellar objects and Optimization of the Rubin LSST Observing Strategy
Abstract1: 
La presentazione consiste nella classificazione, mediante il confronto delle rispettive curve di luce (LCs), di oggetti stellari giovani (YSOs) caratterizzati da variabilità su diversi tempi scala. Inoltre, vengono usate queste stesse LCs come base per uno studio sull’ottimizzazione della strategia osservativa relativa alla Legacy Survey of Space and Time del telescopio Vera C. Rubin, al fine di trovare la cadenza di
campionamento più efficace per ricreare le LCs nei vari tempi scala considerati.
Dopo aver descritto rapidamente il processo di accrescimento per le YSOs, vengono date informazioni in merito al telescopio Vera C. Rubin e al funzionamento della survey. Segue la classificazione fotometrica delle YSOs, con il relativo studio sull’ottimizzazione della strategia osservativa, per concludere con la visione
di una LC ricavata da dati simulati, ottenuti dalla Rubin Science Platform, l’infrastruttura Rubin usata per l’analisi dati dei futuri dati Rubin.

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Speaker2: Simona Caserta
Titolo2: FORMAZIONE PLANETARIA: FORMAZIONE DEI PIANETI TERRESTRI
Abstract2: 
La presentazione mira a descrivere il processo di formazione di un pianeta di tipo terrestre in accordo allo scenario di accrescimento sequenziale.
Le domande a cui si vuole dare una risposta sono:
Come piccole particelle solide crescono all’interno del disco protoplanetario, sede di formazione planetaria?
Come si formano i pianeti terrestri?
Dopo aver illustrato le caratteristiche principali del disco protoplanetario, si procede alla descrizione del processo di crescita dei granelli di polvere in planetesimi.
Successivamente, viene descritta la crescita dei planetesimi in protopianeti, spiegando il fenomeno della focalizzazione gravitazionale e mostrando i due principali modi di crescita: crescita ordinata e crescita runaway. Per mostrare l’evoluzione dei planetesimi, viene realizzato un modello numerico, il metodo diretto
degli N-corpi, che consiste nel risolvere le equazioni del moto associate agli N planetesimi per integrazione. Infine, viene descritta la fine della crescita dei protopianeti e l’assemblaggio dei pianeti terrestri, elencando i
risultati ottenuti da simulazioni numeriche.

Oct
6
Thu
Seminario: prova tesi di laurea M. Sansica (UNIPA)
Oct 6 @ 15:00 – 16:30

Indirizzo Google Meet: https://meet.google.com/jsc-eufh-iek

Speaker: Mauro Sansica (UNIPA)
Titolo: ANALISI IN BANDA X DEI BRILLAMENTI DELLA STELLA T TAURI TW HYA
Abstract:
Le T Tauri Stars sono stelle di piccola massa principalmente localizzate in regioni di formazione stellare e responsabili di una forte emissione di raggi X causata da una elevata attività magnetica. La principale componente di emissione X è legata ai brillamenti che sono in grado di scaldare il plasma coronale fino a temperature superiori ai 100 MK. A questa categoria di stelle appartengono le Classical T Tauri Stars, dotate di un disco di accrescimento che, interagendo con le strutture magnetiche stellari, sembrrerebbe influire sull’attività magnetica.
Per comprendere meglio le proprietà magnetiche e coronali di una stella con accrescimento, presento in questo lavoro di tesi uno studio sui brillamenti X della stella TW Hydrae, rivelati durante i 537 ks di osservazione effettuata con il telescopio spaziale Chandra con al fuoco il rivelatore ACIS-S e l’utilizzo del grating HETG.
Attraverso lo studio spettroscopico risolto in tempo dell’emissione X dei brillamenti più intensi ho avuto modo di risalire alle dimensioni delle loop generate e all’intensità dei campi magnetici necessari per confinare il plasma.
L’analisi della frequenza e della distribuzione energetica dei brillamenti su una stella a distanza così ridotta dal Sistema Solare come TW Hya, permetterà di evidenziare eventi poco intensi che in generale gli studi su vaste aree di formazione stellare a distanze notevoli non riescono a rivelare.

Nov
7
Mon
visita museo istituto paritario trinacria
Nov 7 @ 9:00 – 13:00

40 studenti

primo turno 9.30

secondo turno 11

 

Nov
8
Tue
Seminario: Giuliana Cosentino (Chalmers University of Technology, SE), Aula, ore 15
Nov 8 @ 15:00 – 16:30

Stanza Google meet: meet.google.com/sxz-cctp-tsc

Speaker: Giuliana Cosentino (Space, Earth and Environment Department, Chalmers University of Technology, SE)

Title: Feedback from Supernova Remnants: triggering Star Formation in the ISM

Abstract: Supernova remnants (SNRs) drive large-scale shocks that locally enhance the density of the surrounding material but also inject vast amounts of energy and momentum that largely perturb and disperse the Interstellar Medium (ISM).
The interplay between these two effects is considered paramount in regulating the star formation efficiency in galaxies. However, how SNRs affect the physical conditions of the ISM is not well constrained from an observational point of view.
In this talk, I will present our work aimed to address this question.
I will show our study of the large scale shock triggered by the SNR W44 on the molecular cloud G034. I will show how the shock, probed by Silicon Monoxide (SiO) and observed with ALMA, enhances the density of the processed gas to values compatible with those required for massive star formation and has helped to shape the cloud. I will also present our exploratory large single-dish
observing program SHREC, aimed to observe the molecular shock tracer
SiO(2-1) toward a sample of 30 SNRs known to be interacting with molecular clouds. I will introduce the aim and technical aspects of SHREC and present the first results obtained toward the SNRs IC443.
IC443 is a well known SNR, expanding into and interacting with a nearby toroidal molecular cloud. Toward the major site of interaction, known as clump G, we estimate the mass of the shocked gas to be 100 Msun.
The shock driven by IC443 into this material enhances its density by a factor >10, to value consistent with those required to ignite star formation. Finally, we estimate that between 35-50% of the momentum injected by IC443 is transferred to the nearby molecular material. Our work therefore indicates that the molecular ISM is an important carrier of the SNR momentum and that the SNR-molecular cloud interaction play a crucial role in the regulating star formation in galaxies.

Nov
14
Mon
Seminario: Marcell Tessenyi (BSS Italia) , 14 Novembre ore 15.00
Nov 14 @ 15:00 – 16:00

Stanza Google Meet: https://meet.google.com/sxz-cctp-tsc

Speaker:  Marcell Tessenyi (BSS Italia)

Titolo: Mauve and Twinkle: UV and infrared satellites delivered through a new model

Abstract:

Mauve and Twinkle are part of a new family of satellites from Blue Skies Space that use the latest commercial space industry developments to deliver scientific missions on vastly accelerated timescales, setting a new pace for science discovery.

Mauve is a low-Earth orbit (LEO) small satellite containing a UV spectrometer and a 15cm class telescope. It is designed to monitor the activity of nearby stars, with a particular focus on M-dwarfs that might host habitable zone planets. The construction begins this year with partners C3S and ISISpace, for a planned launch in early 2024. Twinkle is a larger LEO satellite carrying a 0.45m telescope and an infrared spectrometer with a simultaneous wavelength coverage from 0.5 to 4.5μm. It is designed to detect the composition of atmospheres of exoplanets orbiting bright stars, as well as solar system objects such as comets and asteroids. The satellite, expected to launch in late 2024, is based on a high-heritage platform from Airbus and an instrument by ABB Canada. Both satellites will provide scientific data highly complementary to existing and upcoming exoplanet related space and ground-based observatories, including NASA/ESA/CSA’s James Webb Space Telescope and ESO’s Extremely Large Telescope.

Blue Skies Space is able to deliver Mauve and Twinkle thanks to the substantial transformations currently on-going in the space sector in Europe and beyond. Blue Skies Space Italia S.R.L. was set up this year to leverage the capabilities and expertise of the Italian science and technology community and help coordinate European science, technology and funding activities.

Nov
23
Wed
Meeting THE StellaR PAth
Nov 23 @ 14:30 – Nov 25 @ 14:45
Nov
25
Fri
Seminario: Gloria Guilluy (INAF-OATo)
Nov 25 @ 11:00 – 12:30
Stanza Google Meet: https://meet.google.com/sxz-cctp-tsc
Speaker: Gloria Guilluy (INAF-OATo)
Titolo: Exoplanetary Atmospheres with GIANO@TNG.
Abstract: I will present the atmospheric characterization study of hot and warm giant planets using the Telescopio Nazionale Galileo (TNG) in the simultaneous GIARPS (GIANO-B + HARPS-N) observing mode. I will focus in particular on our ongoing efforts to probe both the lower and the upper exoplanetary atmospheres using the near-infrared (0.95-2.45 \mu m) arm of GIARPS: the high-resolution (R /sim 50 000) spectrograph GIANO-B. On the one hand, I will discuss our investigations of the deeper exo-atmospheric layers performed through the search of molecular species (e.g., water, methane, carbon dioxide, hydrogen cyanide) which, by constraining the planet’s C/O ratio, provide clear proxies on planetary formation. On the other hand, I will show our upper exoplanetary atmospheres’ analysis realized through the detection of the individual contributions of atoms (more precisely the metastable helium line at 1083.3 nm). The helium line, in addition to providing key insights into an exoplanetary exosphere, allows for putting constraints on evolutionary processes (i.e. hydrodynamic escape, the mass loss rate, and the morphology of the escaping material).
Dec
15
Thu
Seminario: Ciro Pinto (INAF / IASF-Palermo)
Dec 15 @ 15:00 – 16:30

Stanza Google Meet: https://meet.google.com/sxz-cctp-tsc

Speaker: Ciro Pinto (INAF / IASF-Palermo)

Titolo: “Fast growth and feedback of black holes accreting beyond the Eddington limit”

Abstract:
The detection of fully-grown supermassive black holes in active galactic nuclei at high redshift, when the Universe was young, challenges the theories of black holes growth, requiring long periods of high accretion, most likely above the Eddington limit. These objects will be difficult to study in detail, even with future advanced observatories. In the nearby Universe there are compact objects with a similar accretion regime that can be used as proxy for primordial black holes. Ultraluminous X-ray sources (ULXs) are mainly nearby stellar-mass black holes and neutron stars accreting above their Eddington limit. This was understood after the discovery of coherent pulsations and cyclotron lines in some ULXs, indicating that at least a fraction of them hosts neutron stars as compact objects and, finally, our discovery of powerful winds as predicted by theoretical models of super-Eddington accretion. ULX winds carry a huge amount of power owing to their mildly relativistic speeds (~0.2c) and are able to significantly affect the surrounding medium, producing the observed 100s pc super bubbles, and limit the amount of matter that can reach the central accretor. The study of ULX winds is therefore quintessential to understand 1) how much and how fast can matter be accreted by black holes and 2) how strong is their feedback onto the surrounding medium in the regime of high accretion rate such as for quasars and supermassive black holes at their peak of growth. I will provide an overview on this phenomenology and discuss how we can use similar techniques onto highly-accreting supermassive black holes to understand their fast growth and feedback onto the host galaxy.