OA@INAF - Istituto Nazionale di Astrofisica
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Manutenzione straordinaria/conversione del Radiopolarimetro solare multicanale decimetrico di Basovizza in Radiotelescopio dedicato a didattica e divulgazione (BART - BAsovizza Radio Telescope)
Get PDFINAF-OATs svolge attività di istruzione e divulgazione da 20 anni. Le attività principali sono le visite con le scuole e il grande pubblico alla Specola M. Hack, osservazioni in remoto con il telescopio didattico del progetto “Le stelle vanno a scuola - SVAS", il laboratorio interattivo “Esploracosmo” e la partecipazione a numerosi festival e mostre scientifiche. INAF-OATs è anche coinvolto nell'organizzazione delle Olimpiadi italiane di astronomia.
Sia il telescopio della Specola M. Hack che il telescopio SVAS, situati nella Stazione Osservativa di Basovizza, sono strumenti ottici.
Per offrire agli studenti ed al pubblico la possibilita' di effettuare osservazioni radioastronomiche, come gia’ fanno altri istituti in Italia ed all’estero abbiamo deciso di convertire a fini didattici/divulgativi l'antenna parabolica di 3m appartenente al sistema di radiopolarimetri solari denominato Trieste Solar Radio System (TSRS), un tempo operativo presso la Stazione osservativa di Basovizza dell’ INAF – Osservatorio Astronomico di Trieste, precedentemente dedicata alla ricezione delle emissioni radio solari decimetriche (e poi dismessa a seguito dei danni subiti da scariche atmosferiche) in un radiotelescopio educativo (BART - BAsovizza Radio Telescope)
Stampa di tavolette tattili per il Festival di Astronomia di Castellaro Lagusello
Get PDFFederico Di GiacomoL’astronomia è uno dei campi del sapere che più affascina e attrae tutte le persone: chiunque può interrogarsi su come si è formato l’Universo, o cosa accadrà quando si spegnerà il Sole, o se esiste vita su altri pianeti. E tutti dovrebbero avere l’opportunità di conoscere le risposte a queste domande, almeno per quanto gli scienziati hanno scoperto finora. Per questa ragione l’Istituto Nazionale di Astrofisica sta perseguendo, da vari anni, strategie per rendere i suoi materiali didattici idonei anche a un pubblico di persone ipovedenti o non vedenti. Le risorse tipicamente disponibili per presentare concetti astronomici a persone con difficoltà visive sono limitate a figure tridimensionali, figure piane tattili e alcune lezioni in Braille. Alcune istituzioni accademiche, luoghi pubblici e musei hanno una selezione limitata di materiali adatti che possono essere utilizzati per elaborare concetti di astronomia e sono disponibili per l'uso da parte di visitatori e studenti ipovedenti. Imparare a presentare i concetti di astronomia secondo le esigenze individuali in questo modo non solo migliora l'apprezzamento individuale dei concetti e l'accesso alla conoscenza scientifica, ma promuove anche una cultura del rispetto per le differenze degli altri.
Questo documento si pone come obiettivo quello di raccogliere e descrivere le prime esperienze di stampa 3D con la stampante Stratasys j55 volte e realizzare una serie di modelli tattili di galassie e costellazioni che saranno utilizzati durante la terza edizione del Festival di Astronomia di Castellaro Lagusello
AstroEDU Report 2022/2023
Get PDFAstroEDU (https://astroedu.iau.org) is the free, open-access platform for educational activities supported by the Office of Astronomy for Education (OAE) of the International Astronomical Union (IAU). Starting from the 1st of April 2022, astroEDU went through a deep reorganization: in this Report, we describe the first year of activities of the Editorial Board (1st of April 2022-1st of April 2023), its achievements and the plans for the near future
Forming intracluster gas in a galaxy protocluster at a redshift of 2.16
Get PDFGalaxy clusters are the most massive gravitationally bound structures in the Universe, comprising thousands of galaxies and pervaded by a diffuse, hot intracluster medium (ICM) that dominates the baryonic content of these systems. The formation and evolution of the ICM across cosmic time1 is thought to be driven by the continuous accretion of matter from the large-scale filamentary surroundings and energetic merger events with other clusters or groups. Until now, however, direct observations of the intracluster gas have been limited only to mature clusters in the later three-quarters of the history of the Universe, and we have been lacking a direct view of the hot, thermalized cluster atmosphere at the epoch when the first massive clusters formed. Here we report the detection (about 6σ) of the thermal Sunyaev-Zeldovich (SZ) effect2 in the direction of a protocluster. In fact, the SZ signal reveals the ICM thermal energy in a way that is insensitive to cosmological dimming, making it ideal for tracing the thermal history of cosmic structures3. This result indicates the presence of a nascent ICM within the Spiderweb protocluster at redshift z = 2.156, around 10 billion years ago. The amplitude and morphology of the detected signal show that the SZ effect from the protocluster is lower than expected from dynamical considerations and comparable with that of lower-redshift group-scale systems, consistent with expectations for a dynamically active progenitor of a local galaxy cluster
Ionisation of inner T Tauri star discs: effects of in-situ energetic particles produced by strong magnetic reconnection events
Get PDFMagnetic reconnection is one of the major particle acceleration processes in
space and astrophysical plasmas. Low-energy supra-thermal particles emitted by
magnetic reconnection are a source of ionisation for circumstellar discs,
influencing their chemical, thermal and dynamical evolution. The aim of this
work is to propose a first investigation to evaluate how energetic particles
can propagate in the circumstellar disc of a T Tauri star and how they affect
the ionisation rate of the disc plasma. To that end, we have collected
experimental and theoretical cross sections for the production of H,
H and He by electrons and protons. Starting from theoretical
injection spectra of protons and electrons emitted during magnetic reconnection
events, we have calculated the propagated spectra in the circumstellar disc
considering the relevant energy loss processes. We have considered fluxes of
energetic particles with different spectral indices and different disc magnetic
configurations, generated at different positions from the star considering the
physical properties of the flares as deduced from the observations obtained by
the Chandra Orion Ultra Deep point source catalogue. We have then computed the
ionisation rates for a disc whose structure has been calculated with the
radiation thermo-chemical code {\tt ProDiMo}. We find that energetic particles
are potentially a very strong source of local ionisation with ionisation rates
exceeding by several orders of magnitude the contribution due to X-rays,
stellar energetic particles and radioactivity in the inner disc
Formation and Alteration of Complex Organics Induced by Energetic Processing
Get PDFThe frozen surface of small bodies in the outer Solar System are exposed to energetic charged particles that alter their chemical composition. Laboratory experiments allow to simulate the interaction between cosmic rays and solar particles with frozen surfaces, showing the formation of complex organic compounds. However, irradiation also determines the destruction of both simple and complex molecules. We here report about recent laboratory experiments to simulate the irradiation and heating of surfaces in the outer Solar System and the detection of complex organics. We also present experiments that will be held on the International Space Station (OREOCube and Exocube) and a new facility to study the alteration induced on such complex organics, as well as on prebiotic species and biosignatures
The Fraction and Kinematics of Broad Absorption Line Quasars across Cosmic Time
Get PDFLuminous quasars are powerful targets to investigate the role of feedback from supermassive black holes (BHs) in regulating the growth phases of BHs themselves and of their host galaxies, up to the highest redshifts. Here we investigate the cosmic evolution of the occurrence and kinematics of BH-driven outflows, as traced by broad absorption line (BAL) features, due to the C IV ionic transition. We exploit a sample of 1935 quasars at z = 2.1-6.6 with bolometric luminosity log(L bol/erg s-1) ≳ 46.5, drawn from the Sloan Digital Sky Survey and from the X-Shooter legacy survey of Quasars at the Reionization Epoch (XQR-30). We consider rest-frame optical bright quasars to minimize observational biases due to quasar selection criteria. We apply a homogeneous BAL-identification analysis, based on employing composite template spectra to estimate the quasar intrinsic emission. We find a BAL quasar fraction close to 20% at z ~ 2-4, while it increases to almost 50% at z ~ 6. The velocity and width of the BAL features also increase at z ≳ 4.5. We exclude the possibility that the redshift evolution of the BAL properties is due to differences in terms of quasar luminosity and accretion rate. These results suggest significant BH feedback occurring in the 1 Gyr old universe, likely affecting the growth of BHs and, possibly, of their host galaxies, as supported by models of early BH and galaxy evolution
Star tracking for pointing determination of Imaging Atmospheric Cherenkov Telescopes. Application to the Large-Sized Telescope of the Cherenkov Telescope Array
Get PDFWe present a novel approach to the determination of the pointing of Imaging Atmospheric Cherenkov Telescopes (IACTs) using the trajectories of the stars in their camera's field of view. The method starts with the reconstruction of the star positions from the Cherenkov camera data, taking into account the point spread function of the telescope, to achieve a satisfying reconstruction accuracy of the pointing position. A simultaneous fit of all reconstructed star trajectories is then performed with the orthogonal distance regression (ODR) method. ODR allows us to correctly include the star position uncertainties and use the time as an independent variable. Having the time as an independent variable in the fit makes it better suitable for various star trajectories. This method can be applied to any IACT and requires neither specific hardware nor interface or special data-taking mode. In this paper, we use the Large-Sized Telescope (LST) data to validate it as a useful tool to improve the determination of the pointing direction during regular data taking. The simulation studies show that the accuracy and precision of the method are comparable with the design requirements on the pointing accuracy of the LST (≤14″). With the typical LST event acquisition rate of 10 kHz, the method can achieve up to 50 Hz pointing monitoring rate, compared to (1) Hz achievable with standard techniques. The application of the method to the LST prototype (LST-1) commissioning data shows the stable pointing performance of the telescope
A Herschel study of the high-mass protostar IRAS20126+4104
Get PDFWe performed Herschel observations of the continuum and line emission from
the high-mass star-forming region IRAS20126+4104, which hosts a well-studied
B-type (proto)star powering a bipolar outflow and is associated with a
Keplerian circumstellar disk. The continuum images at six wavelengths allowed
us to derive an accurate estimate of the bolometric luminosity and mass of the
molecular clump enshrouding the disk. The same region has been mapped in 12
rotational transitions of carbon monoxide, which were used in synergy with the
continuum data to determine the temperature and density distribution inside the
clump and improve upon the mass estimate. The maps of two fine structure oxygen
far-IR lines were used to estimate the volume density of the shocked region at
the surface of the southern lobe of the outflow and the mass-loss rate. Our
findings lend further support to the scenario previously proposed by various
authors, confirming that at the origin of the bolometric luminosity and bipolar
outflow from IRAS20126+4104 is a B-type star located at the centre of the
Keplerian disk
LeMMINGs. V. Nuclear activity and bulge properties: A detailed multi-component decomposition of e-MERLIN Palomar galaxies with HST
Get PDFWe used high-resolution HST imaging and e-MERLIN 1.5-GHz observations of galaxy cores from the LeMMINGs survey to investigate the relation between optical structural properties and nuclear radio emission for a large sample of galaxies. We performed accurate, multi-component decompositions of new surface brightness profiles extracted from HST images for 163 LeMMINGs galaxies and fitted up to six galaxy components (e.g. bulges, discs, AGN, bars, rings, spiral arms, and nuclear star clusters) simultaneously with Sérsic and/or core-Sérsic models. By adding such decomposition data for ten LeMMINGs galaxies from our past work, the final sample of 173 nearby galaxies (102 Ss, 42 S0s, 23 Es, plus six Irr) with a typical bulge stellar mass of M∗,bulge ∼ 106 − 1012.5 M⊙ encompasses all optical spectral classes: low-ionisation nuclear emission-line region (LINER), Seyfert, Absorption Line Galaxy (ALG), and H II. We show that the bulge mass can be significantly overestimated in many galaxies when components such as bars, rings, and spirals are not included in the fits. We additionally implemented a Monte Carlo method to determine errors on the bulge, disc, and other fitted structural parameters. Moving (in the opposite direction) across the Hubble sequence, that is from the irregular to elliptical galaxies, we confirm that bulges become larger, more prominent, and round. Such bulge dominance is associated with a brighter radio core luminosity. We also find that the radio detection fraction increases with bulge mass. At M∗,bulge ≥ 1011 M⊙, the radio detection fraction is 77%, declining to 24% for M∗,bulge 10 M⊙. Furthermore, we observe that core-Sérsic bulges tend to be systematically round and to possess high radio core luminosities and boxy-distorted or pure elliptical isophotes. However, there is no evidence for the previously alleged strong tendency of galaxies' central structures (i.e. a sharp Sérsic, core-Sérsic dichotomy) with their radio loudness, isophote shape, and flattening. Full Tables B.1-B.5 are only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (ftp://130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/675/A105</A