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High resolution spectroscopy & wide field:

High resolution spectroscopy & wide field:. prospects for Clusters and WHIM. Silvano Molendi (IASF Milano/INAF). Setting the context. Hot topics identified in ASI 2004 Feasibility Study for GC and IGM Workpackage. Cluster outer regions Cool cores Hard Excess emission

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High resolution spectroscopy & wide field:

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  1. High resolution spectroscopy & wide field: prospects for Clusters and WHIM Silvano Molendi (IASF Milano/INAF)

  2. Setting the context Hot topics identified in ASI 2004 Feasibility Study for GC and IGM Workpackage • Cluster outer regions • Cool cores • Hard Excess emission • Emission from WHIM/Soft Excess ✘

  3. Why ?

  4. Outer Regions Outer regions are very important, this is where the ICM gets its energy, possibly B field and metals, processes occuring here will influence the cluster as a whole As long as we do not have a solid observational characterization of cluster outer regions our understanding of clusters as a whole will be limited.

  5. Cores XMM-Newton and Chandra have revolutionized our understanding of cluster cores: plasma is not cooling below a few KeV, although cooling time is very short. Some form of heating is offseting the cooling. Various heating mechanisms have been investigated, no definite answer has been reached

  6. Cores One of the major difficulties is that we know relatively little of the dynamics of the plasma. Indirect evidence that gas motions with velocities ½ of cs are common in cores (e.g. Ghizzardi et al. 2005). We do not know in what form these flows are: laminar or turbulent, how much kinetic energy with respect to total thermal etc.. Very important to map cores using high spectral resolution instruments with adequate spatial resolution.

  7. Soft Excess/continuum Over the last 10 years various authors have reported evidence of soft X-ray/EUV emission in excess of thermal emission. Both non-thermal oand thermal (WHIM) origin have been considered. Taken at face value some of the latest results (i.e. Bonamente et al. 2005) imply either warm gas with mass comprable to that of the hot plasma or a population of relativistic electrons filling the whole cluster.

  8. WHIM Both theory and observations provide indications that a sizeable fraction of the baryons in the local Universe are contained in warm-hot filaments distributed in IGM. Since WHIM is contaminated by heavy elements it may be detected through lines either in emission or absorption • It would be important to: • map distribution of WHIM • study its physical state

  9. How ?

  10. Cluster Outer Regions Need to go a factor 100 down in SB wrt XMM/Chandra • Large FOV 1 degree • Large Eff. Areas >1000 cm2 • Low Instrumental bkg (smaller than residual CXB) • Low CXB (High spatial resolution) • Observing strategy

  11. Soft Excess-continuum See outer regions Only difference is E band

  12. Map WHIM in emission lines • OVII or OVIII • High spectral resolution 1/300 • Large FOV ½ deg • Eff Area > 200 cm2 • Modest spatial res. 1.5 arcmin

  13. Cores Dynamics • High Resolution Spectroscopy 1/1000 • XMM-like spat. res. 15 arcsec • Telescope Area > 300 cm2 • Background not an issue • FOV 20 arcmin

  14. Requirements Costa, Perola & Puglierin 2004

  15. Mission concepts/1 DIOS NEW • WHIM mapping in emission • additional science: GRB emission/absorption lines. Galactic Foregrounds • Will NOT address issue of cluster outer regions • Limited contribution to core studies, insufficient spatial resolution

  16. Mission concepts/2 WFXRT Panoramix • Cluster outer regions • additional science medium/deep surveys (2 Nasa White papers) • Will NOT address issue of cluster cores • Will address issue of WHIM in continuum emission (of all possible ways of addressing the WHIM issue this is the weakest)

  17. Convergence M1 + M2 Study of low SB sources requires experiments which differ from those used for studies of bright point sources. The parameters you optimize for are different. The scientific community interested in diffuse sources is minoritarian or under-represented. It might be wise to think of one mission for diffuse emission.

  18. Convergence • WFXRT telescope + • 2 focal plane instruments: • micro-calorimeter • CCDs or other high spat res • WHIM with emission lines & continuum • GRBs emission & abs lines • Cluster outer regions • Survey • Cool cores

  19. Synergy M1 + M2 Cluster Formation Process Observe gas before it accretes on cluster Observe gas after it has accreted Oxygen Bias Map WHIM in lines Map WHIM in continuum Black Hole-Galaxy / Diffuse Emission Map diffuse emission Map point sources GRBs

  20. NEW and GCs outskirts Simulation with 5 eV detector 1500cm2 area 100 sq.arcmin 0.4-0.5 r_virZ = 0.2 solkT = 3.0 keVz = 0.02

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