Last updated by S. di Serego Alighieri, 21 March 2017
Tuesday 4 April 2017 - 11:45 Aula A
Luca Del Zanna [Univ. Firenze] (High Energy)
Fast reconnection in relativistic plasmas
Reconnection in magnetically dominated plasmas is often invoked to explain sudden energy release in many high-energy astrophysics scenarios, though models typically fail to provide the required short timescales. Here we present the first simulations of the tearing instability in the framework of relativistic resistive MHD, leading to explosive events occurring on a few light crossing times of the current sheet length.
Francesca Brunetti [OAArcetri] (Library)
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 there 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 three 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 approximately, but everybody is strongly advised to come by 11:45 so not to miss the... beginning of the talks!
The Astrobigné Organizing Committee is currently composed of Sperello di Serego Alighieri (reference person for the extragalactic group), Fabrizio Massi (for the planets and star formation group, solar physics area), Luca Fini (for the technological area), and Antonella Gasperini (for the library, outreach and history), supported by our director Filippo Mannucci and by the invaluable help of Emanuela Masini with the "real" stuff. If you wish to give a presentation, first contact the relevant reference person and then fill in the doodle!
Tuesday 21 March 2017 - 11:45 Aula A
Emanuele Nardini [OAArcetri] (AGN)
Transient iron fluorescence: new clues on the AGN disk/corona?
Our recent discovery of rapid Fe-K variability in the Seyfert galaxy Ark 120 poses several challenges to the commonly adopted X-ray emission paradigm in AGN. I will discuss some possible implications for the structure and properties of the disk/coronal system.
Sperello di Serego Alighieri [OAArcetri] (Telescopes)
The future of the TNG
I will report on the workshop on "The mission and the scientific perspectives of TNG in the 2020 astrophysics" held in Padova on 1-3 March 2017.
Tuesday 7 March 2017 - 11:45 Aula A
Ang Liu [OAArcetri] (Extragalactic)
Searching for bulk motions in the intracluster medium of massive, merging clusters with Chandra CCD data
We search for bulk motions in the intracluster medium (ICM) of massive clusters showing evidence of an ongoing or recent major merger with spatially resolved spectroscopy in Chandra data. We find several cases where significant bulk motions are present in the ICM, including the famous Bullet cluster.
Filippo Mannucci [OAArcetri] (INAF)
News from INAF
The topics discussed during the last meeting of the INAF directors will be presented, especially about the ongoing process to write the new INAF charter. This talk will be in Italian
Tuesday 21 February 2017 - 11:45 Aula A
Guido Risaliti [Univ. of Firenze] (Extragalactic)
Quasars as standard candles
The non-linear relation between the X-ray and UV luminosity in quasars provides a way to estimate their distances, and to build a Hubble Diagram covering the whole z=0-6 range. This diagram can be used to constrain the cosmological parameters and to test possible deviations from the standard Lambda-CDM model.
Linda Podio [OAArcetri] (Star Formation)
JWST capabilities and early science
I will briefly recall the JWST instrumentation and capabilities and the timeline and requirements for Early Science proposal submission. Then, I will present a couple of science cases in the field of star formation that will be proposed by the JEDI collaboration (JEts and Disks @Inaf) for the JWST ESR.
Sperello di Serego Alighieri [OAArcetri] (History of Astronomy)
The reform of the chinese calendar at Galileo's time
The more than 3000 years old chinese calendar will be described, untill its last reform which happened in the first half of the 17th century following the advice of European Jesuit missionaries.
Tuesday 7 February 2017 - 11:45 Aula A
Paolo Tozzi [OAArcetri] (Outreach)
Our nights are better than your days
The programme for the Notti d'Estate 2017
Alessio Turchi [OAArcetri] (Software)
Apache Spark: how to stop worrying and love the data
A very short introduction to "Big Data" technologies and map-reduce paradigm. Apache Spark is a powerful tool that expands the map-reduce paradigm and simplifies the parallel aproach to data processing.
Michele Perna [OAArcetri] (Extragalactic)
Outflow incidence and dependence on AGN luminosity
The connection between the growth of super-massive black holes and the evolution of their host galaxies has been investigated analysing SDSS spectra of a large sample of X-ray detected AGNs. I'll present some results regarding the nature and the fraction of outflowing gas in AGNs, as well as the nuclear conditions possibly at the origin of feedback phenomena.
Tuesday 24 January 2017 - 11:45 Aula A
Luca Fini [OAArcetri] (Technology)
The recent attack to our mail server
At the beginning of December 2016 our mailserver was practically put down for several days by a massive attack using a legitimate account with stolen password. I will present a brief analysis of what happened and what we could do to avoid it happening again.
Davide Fedele [OAArcetri] (Planet Formation)
ALMA reveals a new planetary system in the making
I will present new high angular resolution millimeter observations of the young protoplanetary system HD 169142 with ALMA. The data reveal a system made of multiple dust rings and gaps with a substantial drop of the gas density inside the dust gap. The resulting gas and dust surface densities hint at the presence of multiple planets shaping the disk structure via dynamical clearing and dust trapping.
Fabrizio Massi [OAArcetri] (Telescopes)
TNG is 20 years old: what future?
A workshop on the Telescopio Nazionale Galileo will be held in Padova on March 1-3, 2017. It is intended as a fundamental step towards a major change, introducing new ways of accessing the telescope, new scientific aims, and new rules for proposals.
Tuesday 6 December 2016 - 11:45 Aula A
Francesco Fontani [OAArcetri] (Star Formation)
The magnetic field drives the fragmentation of massive star-forming clouds into individual stars
I will present ALMA observations at 0.25'' resolution of a very young massive star-forming clump, IRAS 16061-5048c1, which clearly indicate that the clump fragmentation is dominated by the magnetic field, as suggested by theory.
Fabio Rossi [OAArcetri] (Software)
Introduction to the Jupyter Notebook
It is an application which runs inside your browser, allowing you to create and share documents that contain live code, equations, visualizations and explanatory text, for applications like teaching, data analysis and reporting, experimenting with programming languages, prototyping software.
Tuesday 22 November 2016 - 11:45 Aula A
Marco Padovani [OAArcetri] (Music & Astronomy)
The Resounding Universe
The immensity of the sky and the sparkling stars have inspired mankind from time immemorial and many scientists were music lovers or even musicians themselves: Galileo, Herschel, Einstein... I will highlight the peculiar and intriguing connection between music and astronomy.
Simone Esposito [OAArcetri] (Instrumentation)
Next VLT instruments and adaptive optics
We briefly report about two new AO based VLT instruments planned for the VLT UT4 (the UT equipped with deformable secondary and lasers). Arcetri is technically involved in both and has already being allocated ~60 nights of GTO for one of them. Involving astronomers in the exploitations of such instruments is indeed mandatory and we would like to stimulate interests on these projects.
Tuesday 8 November 2016 - 11:45 Aula A
Filippo Mannucci [OAArcetri] (Instrumentation)
What will we do with MAORY/MICADO?
The first light of the E-ELT high-resolution camera MICADO fed by the AO system MAORY is expected in 2024. The MAORY science working group is starting to collect updated science cases to create a document on the science allowed by the new telescope. I will present the properties of the instrument and present the possibility for everyone of contributing to the process.
Mikkel Stockman [DARK, Copenhagen] (Extragalactic)
Counting Holes in the Universe: Statistics of Ly-a voids at z~2-4
Using VLT (UVES) and Keck (HIRES) high resolution quasar spectra (R~50.000) in the range 2≤z≤4, we compare the observational number of Lyman-α voids to expectations from recent hydrodynamical simulations by Graziano Rossi et al. (2014).
Tuesday 18 October 2016 - 11:45 Aula A
Matilde Mingozzi [OAArcetri] (Extragalactic)
Investigating the AGN-starburst connection in a nearby Seyfert galaxy
We have analyzed and modelled the CO emission of a nearby Seyfert galaxy, NGC 34, with the aim of understanding the ISM properties in terms of density, temperature and dominant radiation field. NGC 34 represents a galaxy "prototype", therefore our approach can be seen as a pathfinder for future studies.
Antonella Gasperini [OAArcetri] (Outreach)
The "Notti d'Estate" 2016
We present a retrospective look at the Notti d’Estate in Arcetri: an overview and some qualitative and quantitative considerations about the public outreach events of the last summer.
Fabrizio Massi [OAArcetri] (Instrumentation)
Observing with the Sardinia Radio Telescope: a visiting astronomer's account
The Sardinia Radio Telescope has come into operation and an Early Science Programme was run from February 1 to May 31, this year. I spent 3 days observing with the SRT at the end of May in the framework of the programme and this talk will be a brief account of those days from the point of view of a visiting astronomer.
Tuesday 4 October 2016 - 11:45 Aula A
Giovanni Cresci [OAArcetri] (Seminars)
ANY GIVEN THURSDAY: a survey on general seminars in Arcetri
We briefly review the results of the survey on the Thursday General Seminars, the plans for the new year, as well as some numbers and statistics on the previous seasons.
John Brucato [OAArcetri] (Solar System)
The Sample Return Mission OSIRIS-REx
OSIRIS-REx was successfully launched into space on 8th September 2016 from Kennedy Space Center. OSIRIS-REx is traveling to Bennu, a carbonaceous asteroid whose regolith may record the earliest history of our Solar System, it will collect and return samples back to Earth seeking answers to the questions that teach us about the history of the Sun and planets and the origin of life on Earth.