1 / 26

(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)

winifred-sarsfield
Download Presentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related