1 / 15

Simona Gallerani (Osservatorio Astronomico di Roma)

The proximity effect around high-redshift quasars. Simona Gallerani (Osservatorio Astronomico di Roma). In collaboration with: T. Roy Choudhury, X. Fan, A. Ferrara, A. Maselli. 8 th February 2010 2 nd Roman Young Researchers Meeting. Cosmic reionization. B I G B A N G.

aglaia
Download Presentation

Simona Gallerani (Osservatorio Astronomico di Roma)

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. The proximity effect around high-redshift quasars Simona Gallerani (Osservatorio Astronomico di Roma) In collaboration with: T. Roy Choudhury, X. Fan, A. Ferrara, A. Maselli 8th February 20102nd Roman Young Researchers Meeting

  2. Cosmic reionization B I G B A N G ~50 kyr ~100 Myr ≤1 Gyr ~13 Gyr recombination process CMB What is the epochof reionization?

  3. Quasars: a class of very bright Active Galactic Nuclei Black Hole Accretion disk Particularly luminous in the rest frame near ultra-violet, i.e. close to the Lyα emission line Dust torus The quasar spectra we observe are strongly affected by the intervening material along the lines of sight

  4. The Lyα forest in quasar absorption spectra α=1216 Å Keck telescope REDSHIFT

  5. Lyα α=1216 Å The observed size of quasar HII regions seems to suggestzrei~6 (Wyithe & Loeb 2004; Wyithe et al. 2005) Proximity effect around high-z quasars Gunn-Peterson through

  6. Numerical simulations SPH CRASH Springel & Hernquist (2003) Maselli et al. (2003) tQ = 107 yr Nγ= 5.2 × 1056 s-1 Mhalo = 2.9 × 1012 h-1 M z = 6.1 <xHI> = 0.1 Lbox = 100 h-1 Mpc Resolution: #particles=23243; mDM= 2109M; mgas= 2108 M

  7. Radiative transfer simulations (Maselli et al. 2003) Results obtained by A. Maselli trough CRASH: a radiative transfer code

  8. Ly emission line Boundary of the Strömgren sphere Red side of the GP through Synthetic spectrum Maselli, SG, Ferrara,Choudhury (2007)

  9. Apparentshrinking Rf systematically underestimates Rd The analysis of ~ 20 quasars at z~6 shows thatobservations are consistent with a highly ionized intergalactic medium at z~6. Maselli, SG, Ferrara,Choudhury (2007), Maselli, Ferrara, SG (2009)

  10. Lyα α=1216 Å Proximity effect along the line of sight Gunn-Peterson through

  11. Transverse proximity effect Proximity effect along the line of sight Gunn-Peterson through Transverse proximity effect

  12. QSO1 QSO2 RD J1148+5252 Mpc Transverse proximity effect: observations Mahabal et al. (2005) Fan et al. (2006)

  13. Transverse proximity effect: observations vs simulations underdense regions HII regions First-ever detection! SG, Ferrara, Fan, Choudhury (2008)

  14. Conclusions Quasar absorption spectra provide a huge amount of information concerning the ionization level of the intergalactic medium, therefore being exquisite tools for constraining cosmic reionization. The analysis of ~ 20 quasars at z~6 shows thatobservations are consistent with a highly ionized intergalactic medium at z~6, suggesting an epoch of reionization at earlier epochs (i.e. zrei >6). The analysis of the spectrum of the most distant quasar known (i.e. at z =6.4) has provided the first-ever detection of the transverse proximity effect in the hydrogen Lyα forest.

  15. Neutral hydrogen map -0.53 -1.67 -2.81 -3.95 -5.09 -6.22 -7.36 Maselli, SG, Ferrara,Choudhury (2007)

More Related