Osservatorio Astrofisico di Arcetri

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AstroBigné seminars season 2014-2015

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Last updated by S. Zibetti, Sept. 18th, 2015

Tuesday 30th June 2015 - 11:45 Aula A
Luca Del Zanna [ASAP (UniFi)] (High Energy)
Alfven waves in the expanding solar wind
The (fast) solar wind turbulent plasma is dominated by Alfvenic fluctuations propagating away from the Sun, with physical properties depending on the heliocentric distance. Here I will discuss the fate of (monochromatic) Alfven waves in such expanding environment via numerical MHD simulations.


Simone Landi [ASAP (UniFi)] (High Energy)
“Ideal”-magnetic reconnection in Magnethydrodynamics: implications for explosive phenomena in Astrophysical plasmas
On how non-ideal instabilities can trigger explosive phenomena in ideal time scales: the “ideal” tearing mode.


Stefano Carniani (Extragalactic)
Fast outflows quenching star formation at high redshift
Negative feedback from accreting black holes is considered a fundamental physical process in galaxy evolution. It is indeed to provide the link between the growth of supermassive black holes and their host galaxies. The [OIII]λ5007 line emission is a good tracer of outflows and ionized gas dynamics in the narrow-line regions of AGN. I will present VLT-SINFONI near-IR integral field spectra of five quasar at redshift z=2.4. The kinematical analysis of the [OIII] line shows complex gas kinematics in a region of several kpc from the location of the AGN, with blue shifted velocities of a few hundreds of km/s and line widths up to 1500 km/s. [OIII] emission likely traces a massive outflow with a conical morphology. Furthermore we detect the presence of faint, narrow (< 200 km/s) [OIII] emission anti correlated with the presence of the fast blue shifted [OIII]. Overall, our data are consistent with a picture in which narrow [OIII] emission traces star forming gas in the host galaxy, which is absent in the conical outflows, as expected when fast outflows quench star formation. This scenario is confirmed by the observations of the Ha emission, tracing star formation in the host galaxy, which is strongly suppressed in the outflows region. Finally, I will present AGN feedback model to describe the ionized gas dynamic and the properties of outflows.


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Tuesday 16th June 2015 - 11:45 Aula A
Sperello di Serego Alighieri
Fiat Lux
Highlights from the Conference "Fiat Lux" held in Rome on June 3-5, 2015


Edvige Corbelli (Extragalactic)
IGM@50 Is the Intergalactic Medium Driving Star Formation?
Highlights from the conference held in Spineto June 8th-12th, 2015


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Tuesday 5th May 2015 - 11:45 Aula A
Elena Masciadri (Techno)
Forecasts of the OT as a support to the ground-based astronomy supported by AO facilities: state of art at Arcetri
In this contribution I will briefly present the state of art of the studies and projects we are carrying on in Arcetri in the context of the forecast of the optical turbulence and atmospherical parameters conceived as a tool to support the ground-based astronomy particularly that assisted by the AO. With ALTA and MOSE we are going towards the setting-up of automatic operational systems for LBT, VLT and the E-ELT. With STARMET we are investigating, in collaboration with LaMMA, the possibility to set-up in Florence an advanced center for the OT forecasts at different top-class telescopes in the world.


Giovanni Morlino (High Energy)
Effect of mass loading in bow shock nebulae
Bow shock pulsar wind nebulae show highly non-smooth tail structures in Hα, radio and X-rays. We investigate the long term dynamics of the bow shock nebulae created by pulsars moving supersonically through partially ionized interstellar medium. Ionization of neutrals penetrating into the pulsar wind tail and the resulting mass loading changes dramatically the flow dynamics of a light leptonic pulsar wind. The photo-ionization by the UV light produced enough massloading to strongly affect the tail flow. Using a quasi 1-D approximation, we find that mass loading leads to the fast expansion of the pulsar wind tail, making the tail flow intrinsically non-stationary. The resulting shapes of pulsar bow shock nebulae, in Hα radio and X-rays, compare favorably with observations.

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Tuesday 21st April 2015 - 11:45 Aula A
Sperello di Serego (General physics & astrophysics)
The Equivalence Principle from Galileo to Einstein
I will briefly discuss the historical and conceptual evolution of the equivalence principle from Galileo (involving just moving bodies and implying the equivalence of gravitational and inertial mass) to Einstein (involving also electrodynamics and constituting the foundation of General Relativity).


Runa Briguglio (Techno)
E-ELT M4 on the go: optical test of the Demonstration Prototype
The M4 is the deformable mirror for the european ELT and has just enter the MAIT phase (manufacturing, integration and test), led by the italian consortium AdOptica. The M4 is a system composed by a 2.6 m diameter monolithic reference plate, 6 thin glass shells, 5316 actuators providing 1 kHz, 100um stroke for the high order adaptive correction. A Demonstration Prototype (M4DP) with two sub-shells has been assembled to allow the verification of the technological updates (with respect to the LBT and VLT mirrors) and of the functioning and testing procedures for the M4. The M4DP was optically calibrated at INAF Merate by a working group led by Arcetri: the optical test allowed to flatten, align and co-phase the shells at the requested 20 nm RMS Wavefront accuracy; also, specific procedures for the M4 calibration were tested. In this AstroBignè presentation I will summarize the optical test activity on the M4DP, looking forward to start again on the M4.


Francesco Fontani (Star Formation)
Deuterated molecules as unexpected chemical tracers for shocks
The process of deuterium enrichment in molecules from the main reservoir HD is initiated in molecular clouds by exothermic gas-phase reactions. For this reason, deuterated molecules have long been used as tracers of the coldens and densest portions of molecular clouds. Although this general framework remains true, the story is not so simple. Based on the results recently obtained with mm interferometers (PdBI and ALMA), I will show observational evidence that deuterated molecules are also excellent tracers of recently shocked regions (i.e. regions in a completely different physical regime), under peculiar circumstances.


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Tuesday 31 March 2015 - 11:45 Aula A
Riccardo Cesaroni (Star Formation)
New Light from HII Regions
Ionized regions around early-type stars are believed to be well known objects, but surprises are still possible. In this short presentation I will describe an unexpected result that was obtained from the comparison of the radio and IR emission of young HII regions and will explain how such a finding might shed (new) light on the O-B star formation process itself.


Francesco Palla et al.
Astrofrontiere 2015
A report of the recent "general assembly" of INAF about the future of astrophysics in Italy. After the intro by Francesco Palla, open time for reports by other participants and discussion.


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Tuesday 10th March 2015 - 11:45 Aula A
Marco Bocchio (Extragalactic)
Dust Processing and Evolution in Extreme Environments


Antonio Pili (High Energy)
Twisted Magnetosphere in General Relativistic Neutron Stars
The phenomenology of the emission of magnetars supports the idea that their magnetosphere are tightly twisted in the vicinity of the star. We will discuss the properties of equilibrium models of magnetized neutron stars endowed with a twisted magnetosphere obtained solving the general relativistic Grad–Shafranov equation, both in the interior and in the exterior of the star.


Paolo Tozzi (Extragalactic)
A revised cool core-starburst connection (and the Phoenix cluster)
Recent results on the cool cores and possible cooling flows in the center of massive galaxy clusters are presented. We argue that, in several cases, the star formation observed in the central galaxy (BCG) is not directly associated to the putative cooling flow. We also report the results from the deep XMM observation of the Phoenix cluster, the largest cooling-flow candidate observed so far.


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Tuesday 24th February 2015 - 11:45 Aula A
Francesco Palla
Exciting news from the European Astronomical Society pdf


Carmelo Arcidiacono (Technology/Solar System)
Spatially resolved M-band emission from Io’s Loki Patera - Fizeau imaging at the 22.8 meter LBT pdf
At the interferometric Focus of the Large Binocular Telescope (LBT) we imaged Io detecting strong M-band (4.8µm) thermal emission arising from Loki Patera. The 22.8-meter baseline of the provides the highest angular resolution yet obtained for ground based observations at this mid-infrared wavelength: ∼32 milliarcseconds (∼100 km at Io) resolving the Loki Patera emission into two distinct maxima originating from different regions within Loki’s horseshoe lava lake...


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Tuesday 10th February 2015 - 11:45 Aula A
Lorenzo Busoni (Techno)
A day with LUCI: a short-movie about struggle for life at the LBT


Antonella Gasperini (Outreach)
The astroBID : preserving and sharing the Italian astronomical heritage  (Note: seminar in Italian!)pdf


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Tuesday 27th January 2015 - 11:45 Aula A
Anna Gallazzi (Extragalactic)
Element abundance ratios and star formation quenching: satellite versus central galaxies pdf
Galaxies' star formation can be affected by the environment in which they live. To understand the extent to which this happens we confront the age and element abundance ratios (indicative of star formation timescale) of galaxies that are accreted as satellites onto a group/cluster with those of galaxies residing at the center of their dark matter halo.


Fabrizio Massi (Planets & Star Formation)
Star-forming structures in Giant Molecular Clouds: core networks, bubbles, and filaments in the Vela Molecular Ridge


Carlo Baffa, Elisabetta Giani (Technology)
Origami: development of a massively parallel module for SKA Pulsar Search Instrument pdf
One of the key scientific projects of the Square Kilometre Array (SKA) radio telescope is a large survey for searching pulsars both in isolated and in binary systems. The data analysis must be performed in real time with an input data rate which is expected to reach 0.6TeraSamples/sec. This problem is well suited for a massively parallel computing engine, but the dimensions of SKA bring this challenge to a new level of difficulty. Here at Arcetri we have finalized the developement of a highly optimized module for GPUs and the implementation on other massively parallel architecture is under study.


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Tuesday 13th January 2015 - 11:45 Aula A
Linda Podio (Planets & Star Formation)
Disk Chemistry with ALMA


Andrea Verdini (Solar Physics)
Turbulence in expanding media
Turbulence causes plasma heating in many astrophysical systems that usually have peculiar inhomogeneities, like expansion, contraction, rotation. Their effect is commonly neglected in numerical simulations of turbulence because of the limited resolution currently achievable. The Expanding Box Model is an approximation that overcomes this difficulty for system in spherical expansion/contraction. I will present an application to the (expanding) solar wind, highlight differences with homogenous turbulence, and discuss possible applications to other expanding/contracting media.


Luca Fini (Technology/Administrative)
La procedura automatica per gli acquisti (Note: this seminar will be in Italian due to the topic being specific to Italian administration and bureaucracy)
Una breve illustrazione delle procedure web-based sviluppate per le pratiche di acquisto di beni e servizi da parte dell'Osservatorio.


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Tuesday 16th December 2014 - 11:45 Aula A
Gianna Cauzzi (Solar physics)
Solar flares and the F-CHROMA project pdf


Gian Paolo Tozzi (Comets)
Rosetta's adventure to comet 67P/CG pdf
After 10 years and a travel of about 6 billions of Km, last August the Rosetta spacecraft entered in orbit (non Keplerian) around the comet 67P/CG. Rosetta started then a global mapping and studying of the comet, followed by the the released of the lander Philae. Unfortunately, because of thecnical problems, the lander jumped back and reached a crater with vary small illumination. In the talk I'll give the last news and results obtained so far by the orbiter and the lander.


Edvige Corbelli (Education & Outreach)
Licei @ Arcetri o Arcetri @ Licei? pdf
Possibili rimedi alla scomparsa dell'astrofisica nei licei


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Tuesday 21st October 2014 - 11:45 Aula A
Joana Santos (Extragalactic)
The reversal of the SF–density relation in a massive, X-ray selected galaxy cluster at z=1.58: results from Herschel


Celia Blain (Technology)
RAVEN, a MOAO demonstrator for the Subaru Telescope


Nicoletta Sanna (Technology)
GIANO, the HR-NIR spectrometer made in Arcetri, is now available at TNG
GIANO is the high-resolution near infrared (0.95-2.45 micron) spectrometer mounted at TNG and it is now offered to the users for the first time (2015A call for proposals).I will briefly show the main instrument characteristics and performances for a proper GIANO proposal preparation.


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Tuesday 7th October 2014 - 11:45 Aula A
Francesco Palla (Star Formation)
The beat of young stars: how asteroseismology reveals stellar ages


Stefano Zibetti (Extragalactic)
The second public data release of the CALIFA Survey


Francesco Tribioli (Technology)
I nuovi server dell'OAA


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Tuesday 16th September 2014 - 11:45 Aula A
Niccolò Bucciantini (High Energy)
IXPE - Imaging X-Ray Polarimetry Explorer


Tommaso Mazzoni (Technology)
Implementation of SLODAR atmospheric turbulence profiling to the ARGOS system


Edvige Corbelli (Extragalactic)
Galaxy masses: far out in space and back in time
Rotation curves are useful tools for measuring galaxy masses and test cosmological models. The degeneracy between the baryonic and dark matter content can be alleviated by tracing the curve very far out and reconstructing the stellar mass via synthesis models. I will outline the latest results and the work in progress on M33 and other nearby low luminosity galaxies.


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