Partial stellar tidal disruption events and their rates

Tidal disruption events (TDEs) of stars operated by massive black holes (MBHs) will be detected in thousands by upcoming facilities such as the Vera Rubin Observatory. In this work, we assess the rates of standard total TDEs, destroying the entire star, and partial TDEs, in which a stellar remnant survives the interaction, by solving 1-D Fokker-Planck equations. Our rate estimates are based on a novel definition of the loss cone whose size is commensurate to the largest radius at which partial disruptions can occur, as motivated by relativistic hydrodynamical simulations. Our novel approach unveils two important results. First, partial TDEs can be more abundant than total disruptions by a factor of a few to a few tens. Second, the rates of complete stellar disruptions can be overestimated by a factor of a few to a few tens if one neglects partial TDEs, as we find that many of the events classified at total disruptions in the standard framework are in fact partial TDEs. Accounting for partial TDEs is particularly relevant for galaxies harbouring a nuclear stellar cluster featuring many events coming from the empty loss cone. Based on these findings, we stress that partial disruptions should be considered when constraining the luminosity function of TDE flares; accounting for this may reconcile the theoretically estimated TDE rates with the observed ones.Comment: 12 pages + Appendix, MNRAS, accepte

Scenario-Driven Search for Pedestrians aimed at Triggering Non-Reversible Systems

Abstract-This paper presents the results of an innovative approach to pedestrian detection for automotive applications in which a non-reversible system is used; therefore the aim is to reach a very low false detection rate, ideally zero, by searching for pedestrians in specific areas only. The great advantages of such an approach are that pedestrian recognition is performed on limited image areas-therefore boosting its timing performance- and no assessment on the danger level is finally required before providing the result to either the driver or an on-board computer for automatic manoeuvres. This system has been extensively tested on two prototype vehicles equipped with one laserscanner, one camera, and brakeby-wire technology both in Italy and Korea; this paper describes the extensive tests and shows performance measurements. I

Mindful approach to University education

A mindful approach to education and training could improve students' reflective capacities and have positive effects on clinical practice because it facilitates a helping relationship. The main aims of this study were to investigate whether participation in a mindful-based University training was associated with increases in mindfulness skills as measured by the 5-Facet M Questionnaire, and to present the Italian validation of the questionnaire. Sixty-seven students from the course Neuro and Psychomotor Therapy were enrolled. They filled in the self-administered 5-Facet M Questionnaire before and 1 month after a mindfulness-based training, focused on role-playing and followed by a feedback group discussion. The Italian version of the 5-Facet M Questionnaire had good psychometric properties. The pre- and post-training analysis showed a significant increase in the subscale 'Observing'. Findings suggest that role-playing and feedback group sessions are valid tools to improve students' mindfulness skills

BriXs ultra high fluxinverse compton source based on modified push-pull energy recovery linacs

We present a conceptual design for a compact X-ray Source BriXS (Bright and compact X-ray Source). BriXS, the first stage of the Marix project, is an Inverse Compton Source (ICS) of X-ray based on superconducting cavities technology for the electron beam with energy recirculation and on a laser system in Fabry-Pérot cavity at a repetition rate of 100 MHz, producing 20–180 keV monochromatic X-Rays devoted mainly to medical applications. An energy recovery scheme based on a modified folded push-pull CW-SC twin Energy Recovery Linac (ERL) ensemble allows us to sustain an MW-class beam power with almost one hundred kW active power dissipation/consumption

Optimisation Study of the Fabry-Pérot Optical Cavity for the MARIX/BRIXS Compton X-Ray Source

We present the study of the optimization of the optical cavity parameters, in order to maximise the flux of scattered photons in the Compton scattering process. In the optimisation, we compensate the losses of the photon number due to the elliptical shape of the laser pulse in optical cavity with a high focusing electron beam

Conceptual Design of a Soft X‐ray SASE‐FEL Source

FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R&D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNR‐ENEA‐INFN‐University of Roma "Tor Vergata" study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, bringing to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an S‐band normal conducting linac with high brightness photoinjector integrated in a RF compressor

A Smart vision systems for advanced LGV navigation and obstacle detection

This article presents the VisLab solution for obstacle detection and navigation support for unmanned vehicles in industrial environments. Although the literature contains many examples to tackle this problem, this solution can be considered innovative as it improves traditional laser-based systems. The proposed system is composed by two sub-systems. The first one is an obstacle detection system, which also allows the detection of hanging obstacles, within a 3D monitored area. This solution outperforms the original laser scanner based system used for safety which was limited to bi-dimensional areas only. Another vision system is used for tracking a guideline on the ground, that solves problems of localizations and drifts that sometimes can happen using the laser and vehicle odometry only. After a long testing phase, the system is actually installed in a modern industrial warehouse in Parma in order to finally estimate its robustness and reliability

Fast Vision-based Road Tunnel Detection

When a vehicle equipped with an artificial vision system enters or exits a tunnel, the camera may temporarly suffer from reduced visibility, or even get completely blind due to quick changes in enviromental illumination.\r \r This paper presents a vision-based system that detects approaching tunnels entrances or exits. The proposed system allows other ADAS (Advanced Driver Assistance Systems) to act on camera parameters to effectively avoid the tunnel blindness effect. Information regarding approaching tunnel entrance can be helpful for other sensors as well and for sensor fusion systems. In terms of path planning, this system can also inform GNSS-based systems (Global Navigation Satellite System), which usually do not receive any signal in tunnels, and trigger dead reckoning techniques.\r \r The proposed system is noticeably fast and therefore well fit to be used as a background process to support other ADAS applications. Document type: Part of book or chapter of boo