On the origin of cores in simulated galaxy clusters (2009)
Mitchell, N. L., McCarthy, I. G., Bower, R. G., Theuns, T., Crain, R. A.
The diffuse plasma that fills galaxy groups and clusters (the intracluster medium) is a by-product of galaxy formation. The present thermal state of this gas results from a competition between gas...
On the Origin of Cores in Simulated Galaxy Clusters (2008)
Mitchell, N. L., McCarthy, I. G., Bower, R. G., Theuns, T., Crain, R. A.
(Abridged) The thermal state of the intracluster medium results from a competition between gas cooling and heating. The heating comes from two distinct sources: gravitational heating from the...
Rauch, M., Haehnelt, M., Bunker, A., Becker, G., Marleau, F., Graham, J., ...
Original article can be found at: http://www.iop.org/EJ/journal/apj Copyright American Astronomical Society DOI: 10.1086/525846 [Full text of this article is not available in the UHRA]
Lighting the universe with filaments. (2007)
The first stars in the universe form when chemically pristine gas heats as it falls into dark-matter potential wells, cools radiatively because of the formation of molecular hydrogen, and becomes...
Molecular cloud regulated star formation in galaxies. (2007)
Booth, C. M., Theuns, T., Okamoto, T.
We describe a numerical implementation of star formation in disc galaxies, in which the conversion of cooling gas to stars in the multiphase interstellar medium is governed by the rate at which...
Molecular cloud regulated star formation in galaxies (2007)
Booth, C. M., Theuns, T., Okamoto, T.
We describe a numerical implementation of star formation in disk galaxies, in which the conversion of cooling gas to stars in the multiphase interstellar medium is governed by the rate at which...
Monaco, P., Moller, P., Fynbo, J., Weidinger, M., Ledoux, C., Theuns, T.
We investigate the effect of peculiar velocities on the redshift space distribution of z>~2 galaxies, and we focus in particular on Ly-alpha emitters. We generate catalogues of dark matter (DM) halos...
The density structure around quasars from optical depth statistics (2005)
Rollinde, E., Srianand, R., Theuns, T., Petitjean, P., Chand, H.
We present a method for studying the proximity effect and the density structure around redshift z=2-3 quasars. It is based on the probability distribution of Lyman-alpha pixel optical depths and its...
Detection of He II reionization in the sloan digital sky survey quasar sample. (2002)
Theuns, T., Bernardi, M., Frieman, J., Hewett, P., Schaye, J., Sheth, R. K., ...
The expansion of the universe leads to a rapid drop in the hydrogen Ly effective optical depth of the intergalactic medium (IGM), N/Aeff(1+z)3.8, between redshifts 4 and 3. Measurements of the...
Detection of He II reionization in the SDSS quasar sample (2002)
Theuns, T., Bernardi, M., Frieman, J., Hewett, P., Schaye, J., Sheth, R. K., ...
The expansion of the Universe leads to a rapid drop in the mean hydrogen Ly-alpha opacity tau of the intergalactic medium (IGM), tau (1+z)^{3.8}, between redshifts 4 and 3. Measurements of the...
Constraints on reionization from the thermal history of the intergalactic medium. (2002)
Theuns, T., Schaye, J., Zaroubi, S., Kim, T-S., Tzanavaris, P., Carswell, B.
The temperature of the diffuse, photoheated intergalactic medium (IGM) depends on its reionization history because the thermal timescales are long. The widths of the hydrogen Lya absorption lines...
Constraints on reionization from the thermal history of the intergalactic medium (2002)
Theuns, T., Schaye, J., Zaroubi, S., Kim, T. S., Tzanavaris, P., Carswell, B.
The temperature of the diffuse, photoheated intergalactic medium (IGM) depends on its reionization history because the thermal timescales are long. The widths of the hydrogen Lyalpha absorption lines...
Temperature fluctuations in the intergalactic medium (2002)
Theuns, T., Zaroubi, S., Kim, T. S., Tzanavaris, P., Carswell, R. F.
The temperature of the low-density intergalactic medium (IGM) is set by the balance between adiabatic cooling resulting from the expansion of the Universe, and photoheating by the ultraviolet (UV)...
Viel, M., Matarrese, S., Mo, H. J., Haehnelt, M. G., Theuns, T.
We present an effective implementation of analytical calculations of the Lyalpha opacity distribution of the intergalactic medium (IGM) along multiple lines of sight (LOS) to distant quasars in a...
Modelling the IGM and the Ly alpha forest at high redshift from the dark matter distribution (2002)
Viel, M., Matarrese, S., Mo, H. J., Theuns, T., Haehnelt, M. G.
A variety of approximate schemes for modelling the low-density intergalactic medium (IGM) in the high-redshift Universe are compared with the results of a large high-resolution hydrodynamical...
Spin-induced galaxy alignments and their implications for weak-lensing measurements. (2001)
Crittenden, R. G., Natarajan, P., Pen, U-L., Theuns, T.
Large-scale correlations in the orientations of galaxies can result from alignments in their angular momentum vectors. These alignments arise from the tidal torques exerted on neighboring...
Predicting the number, spatial distribution and merging history of dark matter haloes (2001)
Monaco, P., Theuns, T., Taffoni, G., Governato, F., Quinn, T., Stadel, J.
We present a new algorithm (PINOCCHIO, PINpointing Orbit-Crossing Collapsed HIerarchical objects) to predict accurately the formation and evolution of individual dark matter haloes in a given...
Monaco, P., Theuns, T., Taffoni, G.
PINOCCHIO (PINpointing Orbit-Crossing Collapsed Hierarchical Objects) is a new algorithm for identifying dark matter halos in a given numerical realisation of the linear density field in a...
PINOCCHIO and the hierarchical build-up of dark matter haloes (2001)
Taffoni, G., Monaco, P., Theuns, T.
We study the ability of PINOCCHIO (PINpointing Orbit-Crossing Collapsed HIerarchical Objects) to predict the merging histories of dark matter (DM) haloes, comparing the PINOCCHIO predictions with the...
Observational signatures of feedback in QSO absorption spectra. (2001)
Theuns, T., Mo, H. J., Schaye, J.
Models for the formation of galaxies and clusters of galaxies require strong feedback in order to explain the observed properties of these systems. We investigate whether such feedback has...
Non-Voigt Lyman-alpha absorption line profiles (1999)
Outram, P. J., Carswell, R. F., Theuns, T.
Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium, and the loss of a physical justification for Voigt profile fitting of the Lyman-alpha...
Low-redshift evolution of the Lyman-alpha Forest (1998)
Theuns, T., Leonard, A., Efstathiou, G.
The low-redshift evolution of the intergalactic medium is investigated using hydrodynamic cosmological simulations. The assumed cosmological model is a critical density cold dark matter universe. The...
Parallel P3M with exact calculation of short range forces (1993)
A P3M (Particle-Particle, Particle-Mesh) algorithm to compute the gravitational force on a set of particles is described. The gravitational force is computed using Fast Fourier Transforms. This leads...