BANDO AAE TEORIA
Transcription
BANDO AAE TEORIA
BANDO AAE TEORIA Fondi 300 kEu / anno Circa 10 programmi finanziati ogni anno selezionati da referee stranieri (16 richiesti) Risultati scientifici dopo il secondo anno Laura Maraschi Modeling the properties of baryon gas in the large scale structure of the universe • Univ. Bologna: Lauro Moscardini • Univ. Roma Tre: Enzo Branchini • Oss. Astr. Torino: Giuseppe Murante • Oss. Astr. Trieste: Matteo Viel Tool: High-resolution hydrodynamical simulations with a detailed description of the physical processes acting on ICM and WHIM. Main goal: Characterization of the baryon gas in galaxy clusters and in the cosmic web for a realistic comparison with present and future X-ray observations. SCIENTIFIC JUSTIFICATION To characterize the thermodynamic of the X-ray emitting plasma at the virial radius Which ngas, T and Sb values do we expect at Rvir ? Are simulated X-ray clusters consistent with the observed ones in the outskirts ? Implications To calibrate the masses (gas and dark matter) in local galaxy clusters to use them as cosmological probes To study the accretion of primordial gas in cluster DM halos ICM at Rvir: Simulated clusters 4 massive objects (Mvir : 1.9-3.4e15, Tvir : 5.5-9.9 keV) simulated using 4 different physical models: gravitational heating plus artificial viscosity, cooling, star formation, feedback, thermal conduction ngas Roncarelli, Ettori et al 06 Tgas ICM at Rvir: Simulated clusters ngas Tgas Unresolved CXB w. CXO (Hickox & Markevitch 05) Sb [0.5-2 keV] Independently from the physics, just gravity We know what we’d observe at R200 (Tgas, Sb): X-ray observations & simulations provide a consistent picture with ngas~r-2.6 & Tgas~r-0.4 & Sb~1e-16erg/s/cm2/arcmin2 Intergalactic filaments at z~3 & clusters and groups at z~0 Borgani & Viel 2009, MNRAS, 392, L26 Intergalactic medium @ z=3 Standard model (left) Model with pre-heating (right) Intracluster medium @ z=0 Standard model (left) Model with pre-heating (right) The goal: to have a pre-heating model able to reproduce at the same time the entropy profiles of clusters and groups and the properties of intergalactic medium The entropy level in galaxy groups at z~0 Borgani & Viel 2009, MNRAS, 392, L26 Sun et al. ‘08: Chandra archival data of 40 nearby groups. No pre-heating: Correct entropy level at r500 R500 Too low entropy at r2500 Need Kfl>100 keV cm2 consistency with data to reach. R2500 Combined with Ly-a data: Either prevent heating low-δ regions at high z Or heat at relatively low z Acceleration of high energy particles in galaxy clusters PI: Gianfranco Brunetti (INAF-IRA, Bologna) Pasquale Blasi (INAF- Oss Arcetri, Firenze) Giancarlo Setti (Univ. Bologna) Claudio Gheller (CINECA, Bologna) Rossella Cassano (INAF-IRA, Bologna) Franco Vazza (INAF-IRA, Bologna) Roberto Fusco-Femiano (INAF- IASF, Roma) Matteo Murgia (INAF- Oss Cagliari) Daniele Dallacasa (Univ. Bologna) Aims: Particle acceleration mechanisms in galaxy clusters, shocks & turbulence in galaxy clusters, non thermal emission from galaxy clusters (gamma, X, radio) Methods: teoretical models & numerical simulations OzLens - Sydney, 30 Sep 2008 Simulations : Shocks in Galaxy Clusters Vazza, Brunetti, Gheller 2008 OzLens - Sydney, 30 Sep 2008 Shocks in Galaxy Clusters Vazza, Brunetti, Gheller 2008 OzLens - Sydney, 30 Sep 2008 Radio Power Turbulent acceleration in GC (Brunetti +al. 2008, Nature 455,944) loss Acc Frequency Low frequency High frequency OzLens - Sydney, 30 Sep 2008 Alfvenic acceleration in GC Brunetti, Blasi, Cassano, Gabici 2008,09 Syn EGRET πo IC Fermi OzLens - Sydney, 30 Sep 2008 Veritas High Energy Emission from Accreting Massive Black Holes along the Cosmic History Coordinatore: Francesco Haardt! RU1: Universita’ dell’Insubria@Como (P.I.: F. Haardt)! RU2: Universita’ di Milano/Bicocca (P.I.: M. Colpi) ! Star bulge! Gas disk! 100 pc! Density wake behind ! at pericenter! Net effects: orbital decay and circularization! Density wake in front ! at apocenter! ...and linking accretion to dynamics.! Orbital separation ! At pericenter passages, the secondary hole collects gas that can be accreted.! As the orbit shrinks and circularizes accretion is more stable, and variability reduced.! L/LEddxt! M1! M2! Self-Consistent Modelling of the Photo-Ionized Environment of Astrophysical Sources PI: Fabrizio Nicastro (INAF-OAR) Co-Is: D. Guetta (INAF-OAR), G. Matt, S. Bianchi (RomaTre) Collab.: Y. krongold (UNAM, Mexico), N. Brickhouse (CfA, USA), M. Elvis (CfA, USA), S. Mathur (OSU, USA) Personale: M. van Adelsberg (INAF-OAR) • Elaborazione codice per la produzione di spettri (In banda UV e X) da plasma ionizzato in equilibrio, in regime otticamente sottile e per ioni nelo stato fondamentale • Estensione del codice ai casi (a) otticamente spesso (trasferimento radiativo), e (b) ioni su livelli accitati (calcolo della popolazione dei livelli) • Estensione del codice ai casi (a) di non equilibrio e (b) dipendente dal tempo PHASE (PHotoionized Absorber Spectral Engine) • • • • • Most up-to-date atomic data-base (for H to Zn) Covers O-X-rays: more than 3000 resonant transitions Solves for Ionization and Level Population Balance (C & P) Computes proper line profile (Voigt) + Radiative Transfer Interfaces with public fitting packages (e.g. Sherpa, XSPEC) Warm Absorbers = AGN Outflows Cosmologically important: Feedback NGC 3783 Chandra MEG 900 ksec exposure PHASE+TEPHOT FeII Level Population Evolution in Time: General GRB light-curve (Time-Evolving PHOToionization) OVI-VIII Ionization Balance Evolution in Time: Typical AGN X-ray Ligh-curve (NGC 4051) D ~ pc Ground n=2 n=3 D ~ kpc Excellent Distance diagnostics! Excellent Density diagnostics! Simulazioni MHD di plasmi relativistici e della loro emissione ad alte energie Responsabile: R.Bandiera Istituto: Oss. Astrof. Arcetri Partecipanti: E.Amato, L.Del Zanna, F.Pacini, D.Volpi Crab PULSAR WIND NEBULAE Raggi X I venti relativistici e magnetizzati prodotti da pulsar sono rallentati in uno shock terminale, dove ha luogo accelerazione di particelle. Dopo lo shock si forma una nebulosa non termica, che mostra nei raggi X una tipica morfologia getto – toro. Simulazioni MHD basate su modelli di vento magnetizzato con un flusso di energia maggiore all’equatore che al polo (e.g. Del Zanna et al. 2004, 2006) riproducono bene quanto osservato. Vela Raggi X Alcuni Recenti Risultati Modelli dello spettro integrato dell’emissione di una Pulsar Wind Nebula, su un’ampia gamma spettrale, dal radio ai raggi gamma. In figura il caso della Crab Nebula. Variazioni multiple di indice spettrale, anche se con una distribuzione delle particelle iniettate a legge di potenza, è un risultato che si ottiene soltanto usando trattazioni multi-dimensionali. Mappe simulate dell’emissione in raggi gamma (Compton inverso). Le dimensioni sono superiori a quelle in banda X ma decrescono con l’energia (eccetto che nella regione equatoriale). (Volpi et al. 2008) La diminuzione delle dimensioni con l’energia è in accordo con le mappe in raggi gamma (risolte solo marginalmente), ottenute con MAGIC. NON-LINEAR PARTICLE ACCELERATION AT SHOCK WAVES: IMPLICATIONS FOR X/ GAMMA RAY ASTRONOMY AND THE ORIGIN OF COSMIC RAYS PI: Pasquale Blasi Staff Members: E. Amato, R. Bandiera, P. Lipari, M. Vietri Postdoc and students: D. Caprioli, G. Cassam‐Chennai, G. Morlino Main Goals 1. Complete the development of a non-linear theory of diffusive particle acceleration at non-relativistic shocks 2. Application of the theory to the case of individual Supernova remnants which show non-thermal Activity 3. Application of the theory to the origin of galactic Cosmic rays 4. Investigation of the implications of the theory for the Transition from Galactic to extragalactic Cosmic Rays MAIN RESULTS! WE DID COMPLETE THE THEORY WITH ! AMPLIFICATION OF MAGNETIC FIELD! BY THE ACCELERATED PARTICLES…! …AND WITH THE DYNAMICAL REACTION OF THE MAGNETIC FIELD ON THE PLASMA ! WE APPLIED THE NLDSA TO THE CASE OF RXJ1713 WHICH HAS RECENTLY BEEN DETECTED AT TeV BY HESS! WE ESTABLISHED THAT MAGNETIC FIELD AMPLIFICATION ! LEADS TO ACCELERATION OF PROTONS TO ~106 GeV (knee)! WE DETERMINED THE CONNECTION BETWEEN SNR AND CR! THROUGH THE COMPLEX PHENOMENON OF ESCAPE! The case of RXJ1713 Aharonian et al. 2007 The case of RXJ1713 MORLINO, AMATO & BLASI 2009 FERMI HESS, CTA H L Spectral and Timing Properties of Isolated Neutron Stars, Magnetars and Related Objects PI: R. TUROLLA PADOVA UNIT: R, TUROLLA, L. NOBILI, A. ALBANO, L. PAVAN, L. ZAMPIERI OAR UNIT: L. STELLA, GL. ISRAEL, E. BOZZO, M. BURGAY, S. DALL’OSSO Magnetar Spectra R. Turolla, A. Albano, F. Bernardini, G.L. Israel, L. Nobili, L. Pavan, N. Rea, S. Zane Observational evidence that the Soft Gamma Repeaters and the Anomalous X-ray Pulsars host an ultra-magnetized neutron star, a magnetar (B > BQED ~ 4.4x1013 G) Quiescent X-ray emission (0.5-10 keV) from SGRs/AXPs modeled by a thermal component (kT ~ 0.5 keV) plus a power law tail (Γ ~ 1.5-4). A high-energy (~ 15-200 keV) tail detected by INTEGRAL in many sources BB PL HE PL Magnetar magnetospheres are twisted, i.e.the B-field has a non-vanishing toroidal component. Large currents (j ≫ jGJ) are required to support the field A physical emission model: thermal photons emitted by the cooling star surface undergo resonant (cyclotron) up-scattering onto magnetospheric charges A twisted dipolar magnetoshpere A Monte Carlo code has been developed to solve radiative transfer in the magnetosphere. Proper account for photon propagation in a strongly magnetized medium and magnetic Compton scattering Seed blackbody Conservative (magnetic Thomson) scattering Spectral model implemented in XSPEC Magnetic Compton scattering HE cut-off due to electron recoil Resonan Cyclotron Scattering explains magnetar spectra in the soft X-ray range. Extension to the 10-200 keV band under way Supergiant Fast X-ray Transients: Standard HMXBs with standard NSs? ~8 ks ISGRI Science Window image sequence XTEJ1739-302 Like many other HMXB: SAX J1818.6-1703 OB supergiant companion stars Outburst X-ray luminosities ~1036-1037 erg s-1 (Sguera et al. 2005) At difference with many others HMXBs: Extremely high X-ray luminosity variations between outburst and quiescence LX~104-105 Sporadic outbursts lasting only few hours LX>2x103 t~500s (for periodic SFXT see Sidoli et al. 2007) Evidences of Pspin~1000-2000 s (>300 s) (Sguera et al. 2006; Walter et al. 2006) (Sakano et al. 2002) OzLens - Sydney, 30 Sep 2008 SFXT: the most extreme case ever observed... ~1037 erg/s IGRJ17544-2619 Caught by Chandra from quiescence to outburst 5 LX~10 t~5 h ~1036 erg/s ~1033 erg/s ~1032 erg/s OzLens - Sydney, 30 Sep 2008 (In't Zand 2005) The Gated accretion model for SFXT sources: OB STA R NS R An interaction very similar to the Earth - Solar Wind case: matter flows away along the magnetosphere (and does not accrete..) a WIN D BOW SHOCK QUIESCENCE: Accretion is inhibited during most of the orbital motion of the NS around it supergiant companion by a MAGNETIC BARRIER ( gives LX~1032-1034 erg/s ) OUTBURST: Sporadic outbursts due to episodes of enhanced accretion due to the presence of “clumps” from the wind of the supergiant companion ( gives LX~1036-1037 erg/s ) Requires Neutron Star magnetic field >1014 G instead of the typical 1012 G Supergiant Fast X-ray Transients might host MAGNETARS!!! OzLens - Sydney, 30 Sep 2008 Quest’anno abbiamo finanziato un nuovo progetto (PI S. Orlando, OA Pa) Sviluppo di simulazioni MHD per fenomeni di accrescimento e dischi in oggetti stellari giovani