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Osservatorio Astrofisico di Arcetri

AstroBigné seminars

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The Astrobigné Organizing Committee is currently composed of Crescenzo Tortora (Questo indirizzo email è protetto dagli spambots. È necessario abilitare JavaScript per vederlo. , reference person for the extragalactic group), Nicoletta Sanna (Questo indirizzo email è protetto dagli spambots. È necessario abilitare JavaScript per vederlo. , galactic group), and Alessio Turchi (Questo indirizzo email è protetto dagli spambots. È necessario abilitare JavaScript per vederlo. , for the technological area), supported by our director Maria Sofia Randich and by the invaluable help of Emanuela Masini with the "real" stuff.


The Astrobigné concept:

Astrobigné is a series of short seminars that are held at the Osservatorio, with the goal of interconnecting the community of people working here, spreading new ideas and results, creating and reinforcing synergies between groups and indiduals. As such, Astrobigne's are meant to be accessible to a broad audience, including astronomers and technology staff, from senior researchers to students. Not by chance, the name "bigné" was chosen to designate something delicious, attractive, quick to grasp and easy to "eat".

In practice, the astrobigne talks:

  • must be short (10 minutes plus 5 for open discussion, strict, 6-8 slides at most)
  • must present only 1-2 key points that people can assimilate quickly should be aimed at triggering later discussions, collaboration, and future activities.
  • at this aim, can also present ongoing work with intermediate results can cover a broad range of topics, including astronomy, technology, historic research, public outreach, organization etc...
  • will NEVER present a general overview of the subject and a complete account of the speaker's work
  • are given in English whenever possible (this is not because we don't love Italian, but we all understand that English is our professional language to be used to foster international collaborations. Not to mention that here usually are non-Italians in the audience).

Astrobigne's take place on Tuesdays, every two weeks in the main auditorium of OAArcetri (Aula A). We usually have two bigne'-talks (10+5minutes each), selected by the organizing committee in order to cover as many different areas of interest as possible. Before the talks, at 11:45, we normally meet in Aula A to socialize and eat real bigne's (pastries!). The talks start at noon, but everybody is strongly advised to come by 11:45 so not to miss the... beginning of the talks!


Next Astrobigné

Tuesday 26 May 2020 - 12:00 on Google Meet

 

Jacopo Soldateschi []

Iron Line from Neutron Star Accretion Disks in Scalar Tensor Theories

Abstract: /The Fe Kα fluorescent line at 6.4 keV is a powerful probe of the space-time metric in the vicinity of accreting compact objects. In this talk I will explain how some alternative theories of gravity, namely Scalar Tensor Theories, that invoke the presence of a non-minimally coupled scalar field and predict the existence of strongly scalarised neutron stars, change the expected line shape with respect to General Relativity. By taking into account both deviations from the general relativistic orbital dynamics of the accreting disk, where the Fe line originates, and the changes in the light propagation around the neutron star, we computed line shapes for various inclinations of the disk with respect to the observer. We found that both the intensity of the low energy tails and the position of the high energy edge of the line change. Moreover we verified that even if those changes are in general of the order of a few percent, they are potentially observable with the next generation of X-ray satellites.

 



 

Archive of past Astrobigné