Osservatorio Astrofisico di Arcetri
AstroBignÓ? seminars season 2014-2015
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Last updated by S. Zibetti, Sept. 18th, 2015
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.
On how non-ideal instabilities can trigger explosive phenomena in ideal time scales: the ò??idealò?? tearing mode.
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]ÞË5007 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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Highlights from the Conference "Fiat Lux" held in Rome on June 3-5, 2015
Highlights from the conference held in Spineto June 8th-12th, 2015
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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.
Bow shock pulsar wind nebulae show highly non-smooth tail structures in HÞÁ, 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 HÞÁ radio and X-rays, compare favorably with observations.
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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).
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 AstroBignÓ? presentation I will summarize the optical test activity on the M4DP, looking forward to start again on the M4.
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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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.
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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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 Gradò??Shafranov equation, both in the interior and in the exterior of the star.
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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At the interferometric Focus of the Large Binocular Telescope (LBT) we imaged Io detecting strong M-band (4.8ÒÅm) 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: ò?Ì32 milliarcseconds (ò?Ì100 km at Io) resolving the Loki Patera emission into two distinct maxima originating from different regions within Lokiò??s horseshoe lava lake...
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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.
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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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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.
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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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.
Possibili rimedi alla scomparsa dell'astrofisica nei licei
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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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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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Previous seasons
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AstroBignÓ? seminars season 2013-2014
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Last updated by S. Zibetti, Dec. 11th, 2014
High angular resolution and sensitivity are mandatory to study the outflows associated to SINGLE high-mass protostars. First results of a survey employing water maser VLBI and continuum VLA observations are presented.
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I will present SINFONI IFU observation of both "negative" and "positive" feedback in action in an outflowing obscured quasar at z~1.6
I will present results on the dynamics and the onset of the classical bar-mode (m=2) instability in differentially rotating relativistic star models in presence of magnetic fields. The study has been achieved by performing full 3D ideal magneto-hydrodynamics simulations in full General Relativity. Magnetic fields of order 1e14 Gauss, or less, have negligible effetcs on both stable and unstable models, while stronger magnetic fields are able to completely suppress the hydrodinamical instabilities which are present in the un-magnetized case.
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A concise view on some fundamental physical and cosmological arguments uncovered by the polarization of the Cosmic Microwave Background.
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2013 saw the beginning of the commissioning phase of ARGOS at the LBT: the laser system was installed on telescope and the first on-sky propagation was performed. In early 2014 the LGS wavefront sensor was also installed and it saw its first light. I will briefly review this commissioning activity and highlight the results obtained.
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I will talk about the new information that submillimeter/Terahertz observations bring us to the study of protostellar outflows, in particular molecular line observations with APEX, SOFIA, and Herschel observatories.
I will briefly describe the idea and proposal for a low budget, fast track near-IR IFU for LBT, in the context of the recent call for new instrumentation at LBT.
I will talk on the importance of reducing the stray light in solar coronagraphy, i.e., on the design process that allows to minimize the light that survives in the shadow of an occulter. In particular, I will focus on the experimental evaluation of the performance improvement that an optimized coronagraph occulter may guarantee.
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I will present the results of Near-Infrared, high-angular resolution (< 0.1") images of massive young stellar objects obtained with adaptive optics and PISCES at LBT. The jet from IRAS20126+4104, an intermediate mass protostar, is shown with unprecedented details.
I knew Cosmic-Rays during my master on Universe Science at the UniversitÓš di Roma Tor Vergata, thanks to the professor Marco Tavani. From that moment, my relationship with them started inside the AGILE team. I studied Cosmic-Rays from an experimental point of view, focusing my work on their acceleration by Supernova Remnants. During my PhD I learned to model gamma-ray emission detected from their acceleration, obtaining important improvements of our relationship. My aim in these two post-doc years with the High Energy Team of Pasquale Blasi is to improve my knowledge of Cosmic Rays from a theoretical point of view, in order to learn the better way to behave with them.
Three decades after the discovery of stellar jets many questions about their nature are still open. In recent years the interest of investigators has moved from establishing the structure and propagation modes of these beautiful nebulae toward understanding what is their role in star formation, and lately what is the feedback they can have on circumstellar disk in the region of planet formation. I will illustrate how recent advances in the construction of instruments for high angular resolution can open new prospects in these studies.
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I will present water observations in low-mass protostellar outflows with Herschel, obtained within the framework of the Guaranteed Time Key Project WISH (Water In Star-forming regions with Herschel), in comparison with VLT observations of H2, which indicate a stratification of the molecular gas in velocity and excitation. I will discuss the implications on the water abundance estimates obtained so far and how this new observations can be used to shed a light on this hot topic.
I will discuss a few key issues in protoplanetary disk evolution with emphasis on planet formation. I will highlight some recent successes and the many interesting problems that we hope to sort out in the future with a combination of radio, millimetre and infrared observations.
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Investigating (with the help of Joseph Conrad and Francis Ford Coppola) the deeply obscured protostellar regions.
In this talk I will briefly describe the numerical investigation of non-ideal effects in relativistic plasmas for a couple of cases: the shear viscosity in the Quark-Gluon Plasma (QGP) fireball created after the collision of heavy ions in accelerators, and the mean-field resistive and dynamo effects believed to be at work in accretion tori around Kerr black holes.
I present the Swift X-ray Cluster Survey and its on-going optical follow up, and outline the scientific questions we can (try to) answer studying the galaxy populations in the SWXCS sample.
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Tuesday 28th January 2014 - 11:45 Aula A
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Linda Podio (Star Formation) pdf
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Nicoletta Sanna (Stars/Technology) ppt pdf
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AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
The MEGA (Meetings ExtraGalactic of Arcetri) is a series of informal Seminars about extragalactic topics held at Arcetri, mostly on Wednesdays.
Indeed they are more informal than the official Arcetri Seminars series, participants are welcome to interrupt with comments and questions, and speakers are invited to talk about on-going work, in order to get constructive comments and to foster local collaborations.
Future MEGA
Please contact Sperello di Serego Alighieri (e-mail: Questo indirizzo email Ó? protetto dagli spambots. Ó? necessario abilitare JavaScript per vederlo. Tel.: 0039 055 2752311) to propose a MEGA.
15 June 2016:Toshio Fukushima,"Rotation Curve of M33 Explained by Disc Dark Matter"
List of past MEGA
17 June 2015:Giulia Savorgnan,"Galaxy vivisection: black hole and host bulge affair"
22 April 2015:Sebastain Sanchez, "Ionized gas in the CALIFA galaxies"
8 April 2015:Jamie Farnes,"Probing Magnetic Fields throughout the Universe"
24 February 2015:Francesco Tombesi,"AGN feedback from accretion winds"
11 February 2015: Guido Risaliti,"A Hubble Diagram for Quasars"
23 January 2015: Enrica Bellocchi,"2D kinematic characterization of a representative sample of local (U)LIRGs: a 'kinemetry' analysis based on VIMOS/VLT Intergal Field Spectroscopy"
22 December 2014: Federico Lelli, "Starbursts and Gas Dynamics in Dwarf Galaxies"
22 October 2014: Enrico Pinna, Lorenzo Busoni, Tino Oliva and Simone Esposito, "Shark, Argos, MOONS and ERIS: Arcetri involvment in next generation instruments at VLT and LBT"
17 September 2014: Peter Camps, "The radiative transfer code SKIRT and its applications to observed and simulated galaxies"
9 July 2014: Francesca Onori, "Looking for the broad emission lines in AGN2 with deep NIR spectroscopy and the measure of the mass of Intermediate Mass" BH"
30 May 2014: Vasiliki Petropoulou, "The 'WALL' large-scale structure in the COSMOS field. Exploring the onset of environment-driven trends at z=0.73"
14 May 2014: Fernando Buitrago, "Stellar haloes of Early-Type massive galaxies at z~0.7 or how to use the HUDF for local Universe studies"
2 April 2014: Anna Gallazzi & Stefano Zibetti, Report on the ESO Workshop about "3D2014: Gas and stars in galaxies: A multi-wavelength 3D perspective"
20 November 2013: Leslie Hunt & Simone Bianchi, "Herschel highlights on large-scale galactic structure and nearby galaxies"
19 September 2013: Kimihiko Nakajima, "Ionization States of galaxies: Evolution, SFR-M_star-Z Dependence, and Ionizing Photon Escape"
14 June 2013: Evan Kirby, "The Universal Mass-Metallicity Relation for Dwarf Galaxies"
29 May 2013: Bernhard Brando, "Zooming in on Starbursts"
15 May 2013: Paulina Lira, "Black Hole mass and growth at high-z"
8 May 2013: Marco Bocchio, "Dust destruction and heating in the IGM"
19 April 2013: Francesco Massaro, "Unveiling the nature of the unidentified gamma-ray sources: blazar counterparts at low radio frequencies"
27 February 2013: Ingyin Zaw, "The Host Active Galactic Nuclei of Extragalactic Water Masers"
6 February 2013: Stefano Carniani, "ALMA observations of a strongly star-forming merging system at z = 4.7"
30 January 2013: Giulia Savorgnan, "Supermassive black holes and host galaxies - The recovery of the M_BH - n relation"
16 January 2013: Guido Risaliti, "Unambiguous tests of general relativistic effects in AGNs with NuSTAR and XMM-Newton"
24 October 2012: Sperello di Serego Alighieri, "The cold Interstellar Medium in Virgo Early-Type Galaxies"
5 June 2012: Laura Magrini, "Scaling relations of metallicity, stellar mass, and star formation rate in metal-poor starbursts: II Models"
23 May 2012: Leslie Hunt, "Scaling relations of metallicity, stellar mass, and star formation rate in metal-poor starbursts: I Observations"
21 December 2011: Silvio Lorenzoni, "Reionizzazione e Lyman-Break galaxies a z=8-9"
14 June 2011: Stefano Zibetti, "Resolved optical-infrared SEDs of galaxies: universal relations and their break-down on local scales"
31 May 2011: Hagai Netzer, "The earliest growth of the most massive black holes: the active z=4.8 universe"
8 April 2011: Filippo Frontera, "Laue lens development for deep gamma-ray observations of celestial objects"
23 December 2010: Emanuele Daddi, "New insights on the nature of massive galaxies in the distant Universe"
13 October 2010: Eleonora Sani, "The Spitzer/IRAC view of black-hole/bulge scaling relations"
16 June 2010: Guido Risaliti, "[OIII] Equivalent Width and Orientation Effects in Quasars"
20 May 2010: Sperello di Serego Alighieri,"Cosmological birefringence: an astrophysical test of fundamental physics"
28 April 2010: Daniel Kunth, "The Lyman-alpha escape fraction of local and cosmological star forming galaxies"
24 March 2010: Filippo Mannucci, "Una relazione tra metallicita', SFR e massa per le galassie"
20 January 2010: Guido Risaliti, "AGN outflows and feedback"
12 November 2009: Carlos Hernandez Monteagudo, "The Large Angle Radio-Cosmic Microwave Background Cross-Correlation: what we expect and what we actually find"
21 October 2009: Eleonora Sani, "Enhanced Star Formation in Narrow Line Seyfert 1 AGN revealed by Spitzer"
1 October 2008: George Helou, "Unbiased Infrared Spectroscopic Surveys"
16 September 2008: Hiroyuki Hirashita, "Far-Infrared Observations of Blue Compact Dwarf Galaxies by AKARI: Dust Properties in Metal-Poor Environments"
25 June 2008: Raffaella Schneider, "The transition from PopIII to PopII stars"
1 April 2008: Marco Grossi, "The gas accretion rate in M33 from the population of HI clouds"
7 November 2007: Alessandro Marconi, "Estimating BH masses from 0 to high redshift"
5 October 2007: Guido Risaliti, "X-ray variability: a tool to investigate the structure of the innermost regions of AGNs"
19 September 2007: Dan Maoz, "Low-luminosity AGNs: their accretion mode and potential as persistent energy feedback sources"
11 July 2007: Sperello di Serego Alighieri, "Il contenuto di idrogeno neutro nelle galassie early-type"
11 April 2007: Simone Bianchi, "Polvere nelle Supernovae"
14 mar. 2007: Marco Salvati, "Proprieta' nei raggi X delle sorgenti radio piu' luminose"
14 February 2007: Eleonora Sani & Emanuele Nardini, "Applicazione e sviluppo di diagnostici in infrarosso: come rilevare la fonte energetica nelle ULIRG e nelle loro controparti lontane"
17 january 2007: Filippo Mannucci, "Perche' le galassie ellittiche nei cluster producono piu' supernovae che quelle di campo?"
14 December 2006: First meeting to discuss the format
AstroBignÓ? seminars season 2012-2013
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Last updated by S. Zibetti, Feb. 4th, 2014
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
AstroBignÓ? Home - Top - Current season - Other Seasons
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