Tomography of the intergalactic medium with Lyα forests in close QSO pairs†

  1. V. D'Odorico1,*,
  2. M. Viel1,2,
  3. F. Saitta3,
  4. S. Cristiani1,
  5. S. Bianchi4,
  6. B. Boyle5,6,
  7. S. Lopez7,
  8. J. Maza7,
  9. P. Outram8

Article first published online: 22 SEP 2006

DOI: 10.1111/j.1365-2966.2006.10941.x

Issue

Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society

Volume 372, Issue 3, pages 1333–1344, November 2006

Additional Information

How to Cite

D'Odorico, V., Viel, M., Saitta, F., Cristiani, S., Bianchi, S., Boyle, B., Lopez, S., Maza, J. and Outram, P. (2006), Tomography of the intergalactic medium with Lyα forests in close QSO pairs. Monthly Notices of the Royal Astronomical Society, 372: 1333–1344. doi: 10.1111/j.1365-2966.2006.10941.x

Author Information

  1. 1

    INAF – Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, Trieste I-34131, Italy

  2. 2

    Institute of Astronomy, Madingley Road, Cambridge CB3 0HA

  3. 3

    Dipartimento di Astronomia, Università degli Studi di Trieste, via G.B. Tiepolo 11, Trieste I-34131, Italy

  4. 4

    INAF – Istituto di Radioastronomia, Sezione di Firenze, Largo E. Fermi 5, Firenze I-50125, Italy

  5. 5

    Australia Telescope National Facility, PO Box 76, Epping, NSW 1710, Australia

  6. 6

    Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia

  7. 7

    Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile

  8. 8

    Department of Physics, University of Durham, Science Laboratories, South Road, Durham DH1 3LE

* E-mail: dodorico@oats.inaf.it

  • †

    Based on observations collected at the European Southern Observatory Very Large Telescope, Cerro Paranal, Chile – Programs 65.O-0299(A), 68.A-0216(A), 69.A-0204(A), 69.A-0586(A), 70.A-0031(A), 166.A-0106(A).

Publication History

  1. Issue published online: 29 SEP 2006
  2. Article first published online: 22 SEP 2006
  3. Accepted 2006 August 14. Received 2006 August 9; in original form 2006 March 17

SEARCH

SEARCH BY CITATION

ARTICLE TOOLS

View Full Article (HTML) Get PDF (681K)

Keywords:

  • intergalactic medium;
  • quasars: absorption lines;
  • cosmology: observations;
  • large-scale structure of Universe

ABSTRACT

We study the three-dimensional distribution of non-virialized matter at z∼ 2 using high-resolution spectra of quasi-stellar object (QSO) pairs and simulated spectra drawn from cosmological hydrodynamical simulations. We have collected the largest sample of QSO pairs ever observed with Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT), with angular separations between ∼1 and 14 arcmin. The observed correlation functions of the transmitted flux in the H i Lyman α forest along and transverse to the lines of sight are in good agreement implying that the distortions in redshift space due to peculiar velocities are small. The clustering signal is significant up to velocity separations of ∼200 km s−1, or about 3 h−1 comoving Mpc. The regions at lower overdensity inline image are still clustered but on smaller scales (Δv≲ 100 km s−1). The observed and simulated correlation functions are compatible at the 3σ level. A better concordance is obtained when only the low overdensity regions are selected for the analysis or when the effective optical depth of the simulated spectra is increased artificially, suggesting a deficiency of strong lines in the simulated spectra. We found that also a lower value of the power-law index of the temperature–density relation for the Lyman α forest gas improves the agreement between observed and simulated results. If confirmed, this would be consistent with other observations favouring a late He ii reionization epoch (at z∼ 3). We remark the detection of a significant clustering signal in the cross-correlation coefficient at a transverse velocity separation Δv⊥∼ 500 km s−1 whose origin needs further investigation.

View Full Article (HTML) Get PDF (681K)