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(Some) astrophysical drivers for a high-resolution imaging X-ray spectrometer

(Some) astrophysical drivers for a high-resolution imaging X-ray spectrometer. Xavier Barcons Instituto de Física de Cantabria (CSIC-UC). Science context. The missing baryons: studies of the Warm and Hot Intergalactic Medium (WHIM)

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(Some) astrophysical drivers for a high-resolution imaging X-ray spectrometer

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  1. (Some) astrophysical drivers for ahigh-resolution imaging X-ray spectrometer Xavier Barcons Instituto de Física de Cantabria (CSIC-UC) Utrecht, 25-26 October 2004

  2. Science context • The missing baryons: studies of the Warm and Hot Intergalactic Medium (WHIM) • Black hole growth rate and spin evolution: measurement of the Fe line profile at different redshifts • Accretion disk precession: binary black holes? Utrecht, 25-26 October 2004

  3. The Warm and Hot Intergalactic Medium Utrecht, 25-26 October 2004

  4. Main goals of WHIM studies • Measure baryon density as a function of z (missing baryons), comparing with cold (Lyman- cloud) component. • Chemical evolution of the Universe (groups/clusters and strong systems). • Heating mechanisms (photoionisation, gravitational heating etc.) • Determine cosmological distribution (filaments) Utrecht, 25-26 October 2004

  5. The Warm & Hot IGM • Large fraction of baryons at T~105-107 K • IGM hotter towards low redshift (baryons falling onto potential wells) • Extra heating might be present due to star formation & AGNs Davé et al 2002 Utrecht, 25-26 October 2004

  6. Thermal history of WHIM Davé et al (2001) Utrecht, 25-26 October 2004

  7. T and ion column density(Fang, Bryan & Canizares 2002) Utrecht, 25-26 October 2004

  8. Fang & Canizares (2000) The expected column density distribution Expect tens of O-VIII absorbers per unit z with N>1015 cm-2 Utrecht, 25-26 October 2004

  9. Doppler parameters: thermal width and turbulence • Typical Doppler param • b~100-200 km s-1 • Larger values for • stronger systems (groups • and clusters) Fang, Byan & Canizares 2002 Utrecht, 25-26 October 2004

  10. Sensitivity: equivalent width detection limit Rule of thumb: For a S/N>10 spectrum, sampled to  2-3 channels per resolution element, narrow absorption lines can be detected with an equivalent width as small as a fraction of a channel width. EW  0.1 eV (5 mA@ 0.5 keV) is a realistic limit for XEUS, if equipped with a 1eV-resolution spectrograph Utrecht, 25-26 October 2004

  11. Sensitivity:expected S/N ratio S(0.5-4.5)=10-13 cgs: 10 sources/deg2 <z>~ 0.5-1.0 XEUS+STJ =2, NHI=2 1020 cm-2 Resolution ~1 eV Exposure time ~ 100 ks No background Utrecht, 25-26 October 2004

  12. 2 eV Sensitivity Curve of growth for OVIII 1 eV ½ eV Utrecht, 25-26 October 2004

  13. Fe line diagnostics in distant AGN Utrecht, 25-26 October 2004

  14. Average rest-frame spectra show relativistic Fe-lines type-1 AGN EW~700eV type-2 AGN EW~500eV Streblyanskaya et al., 2004 Lockman Hole800 ks XMM-Newton observation XEUS should be able to determine redshifts and study Fe lines individually Utrecht, 25-26 October 2004

  15. Fe line profile in distant AGN • A relativistic Fe line profile provides information on the innermost parts of the accretion disk and, eventually, on the SMBH itself (spin) • Assume: • Concurrence cosmology • L(0.5-2)=1044 erg s-1, =1.9 • Laor profile, incl=30º, Rmin=10, Rmax=400, =2. • EW=300 eV • 1 Ms exposure Utrecht, 25-26 October 2004

  16. z=1 z=2 z=5 z=3 Spectral resolution Utrecht, 25-26 October 2004

  17. Evolution of SMBH spin • Fe line profile potentially testable out to z~3-5 for typical type 1 AGNs, but requires long exposures • NFI’s can do better than WFI, but only one object at a time. • Study of samples to that level of detail very unlikely Utrecht, 25-26 October 2004

  18. Binary SMBHsand disk precession Utrecht, 25-26 October 2004

  19. XEUS tests of binary SMBHs • Super-massive Black Holes in galaxy centres + mergers implies binary SMBHs. • Evidence from long-term variability in the BL Lac OJ 287 (Sillanpää et al 1988) and others. • Binary SMBHs might be stable over very long periods (Valtaoja et al 1989) Mergers might play an important role in SMBH growth along cosmic history Utrecht, 25-26 October 2004

  20. Jet precession in 3C273 • Jet precession from VLBI long-term monioring (Abraham & Romero 1999) Model fits to 16 year Jet precession Utrecht, 25-26 October 2004

  21. A binary SMBH in 3C273? Incl=8º-14º • Romero et al (1999) find that the jet precession does likely arise from precession in the accretion disk. • Effects on the Fe line profile: • Azhimutally averaged • Orbital period ~105 s Incl=56º-62º Utrecht, 25-26 October 2004

  22. Accretion disk precession • Causes: • Binary SMBH, one dominating X-ray emission. • Non-aligned SMBH spin and accretion disk axis not aligned Accretion disk precession due to the close SMBH • The relativistic Fe emission line will change as a result of a change in inclination angle: • Shape (especially blue edge) • Intensity Utrecht, 25-26 October 2004

  23. Simulations • L(2-10)= 6.25 x 1045 erg s-1, =1.6, z=0.158 • Fe line with EW=200 eV (Yaqoob & Serlemitsos 2000) • Simulations with various inclination angles and BH angular momenta (Schwarzschild and maximally rotating Kerr • Disk emissivity profile  r-2.5 Utrecht, 25-26 October 2004

  24. XEUS/TES vs CONX/Calorimeter 100 ks, inclination angles separated 4º Sharp blue edge of Fe line Strongly dependent on inclination Utrecht, 25-26 October 2004

  25. Results • XEUS/TES delivers inclination angle with precission 0.3º (90% confidence) in 100 ks. • CONSTELLATION-X/2eV delivers inclination angle with precission 1º (90% confidence) in 100 ks. • Spectral resolution essential • Effective area necessary to test fainter sources See Torres, Romero, Barcons & Yun (2004, ApJL, astro-ph/0308300) Utrecht, 25-26 October 2004

  26. Imaging spectrometers Point and extended sources Degraded redshift sensitivity High efficiency Gratings Point sources only Flat redshift sensitivity (/~constant) Moderate efficiency Do we need a CIS for this science? High spectral resolution certainly needed in the full 0.2-8 keV bandpass: 2 different instruments Utrecht, 25-26 October 2004

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