Growing the first bright quasars in cosmological simulations of structure formation (2009)
Sijacki, Debora, Springel, Volker, Haehnelt, Martin G.
We employ cosmological hydrodynamical simulations to study the growth of massive black holes (BHs) at high redshifts subject to BH merger recoils from gravitational wave emission. We select the most...
Regan, John A., Haehnelt, Martin G.
Large dynamic range numerical simulations of atomic cooling driven collapse of gas in pre-galactic DM haloes with T_vir ~ 10000 K show that the gas loses 90% and more of its angular momentum before...
Regan, John A., Haehnelt, Martin G.
We have used the hydrodynamical AMR code ENZO to investigate the dynamical evolution of the gas at the centre of dark matter haloes with virial velocities of ~ 20 - 30 kms and virial temperatures of...
Barnes, Luke A., Haehnelt, Martin G.
The recently discovered population of ultra-faint extended line emitters can account for the majority of the incidence rate of Damped Lyman Alpha systems (DLAs) at z ~ 3 if the line emission is...
Viel, Matteo, Becker, George D., Bolton, James S., Haehnelt, Martin G., Rauch, Michael, Sargent, Wallace L.
We present constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-alpha flux power spectrum of 55 high-resolution HIRES spectra at 2.0~5.6 keV (2sigma) for sterile...
Detecting quasars at very high redshift with next generation X-ray telescopes (2008)
Rhook, Kirsty J., Haehnelt, Martin G.
The next generation of X-ray telescopes have the potential to detect faint quasars at very high redshift and probe the early growth of massive black holes (BHs). We present modelling of the evolution...
Viel, Matteo, Becker, George D., Bolton, James S., Haehnelt, Martin G., Rauch, Michael, Sargent, Wallace L. W.
Martin G. Haehnelt, Michael Rauch, Hubble Fellow
Estimates of the linear extent of heavy-element absorption systems along the line-of-sight to a QSO often assume that the cloud is photoionized and that the temperature takes the equilibrium value...
Probing the thermal history of the Intergalactic Medium with (2007)
Absorption Lines, Martin G. Haehnelt, Matthias Steinmetz
The Doppler parameter distribution of Lyff absorption is calculated for a set of different reionization histories. The differences in temperature between different reionization histories are as large...
Michael Rauch, Martin G. Haehnelt, Matthias Steinmetz
In a hierarchical cosmogony galaxies build up by continuous merging of smaller structures. At redshift three the matter content of a typical present-day galaxy is dispersed over several individual...
Bolton, James S., Haehnelt, Martin G.
We examine a large set of synthetic quasar spectra to realistically assess the potential of using the relative sizes of highly ionized near-zones in the Lya and Lyb forest as a probe of the neutral...
Bolton, James S., Haehnelt, Martin G.
We use a large set of hydrodynamical simulations, combined with measurements of the Lyman alpha opacity of the IGM taken from the literature, to obtain robust estimates for the photoionization rate...
Probing the growth of supermassive black holes at z>6 with LOFAR (2006)
Rhook, Kirsty J., Haehnelt, Martin G.
HII regions surrounding supermassive black holes (BHs) in an otherwise still neutral intergalactic medium (IGM) are likely to be the most easily detectable sources by future 21cm experiments like...
Bolton, James S., Haehnelt, Martin G.
We use state-of-the-art hydrodynamical simulations combined with a 1D radiative transfer code to assess the extent to which the highly ionized regions observed close to z~6 quasars, which we refer to...
Numerical Simulations of the Lyman-alpha forest - A comparison of Gadget-2 and Enzo (2006)
Regan, John A., Haehnelt, Martin G., Viel, Matteo
We compare simulations of the Lyman-alpha forest performed with two different hydrodynamical codes, Gadget-2 and Enzo. A comparison of the dark matter power spectrum for simulations run with...
Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)
Viel, Matteo, Lesgourgues, Julien, Haehnelt, Martin G., Matarrese, Sabino, Riotto, Antonio
We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey \lya flux power spectrum at 2.2
The Lyman-alpha forest and WMAP year three (2006)
Viel, Matteo, Haehnelt, Martin G., Lewis, Antony
A combined analysis of Cosmic Microwave Background (CMB) and Lyman-a forest data allows to constrain the matter power spectrum from small scales of about 1 Mpc/h all the way to the horizon scale. The...
Haehnelt, Martin G., Davies, Melvyn B., Rees, Martin J.
Attempts of Magain et al (2005) to detect the host galaxy of the bright QSO HE0450--2958 have not been successful. We suggest that the supermassive black hole powering the QSO was ejected from the...
The impact of galactic winds from LBGs on the Intergalactic Medium (2005)
Desjacques, Vincent, Haehnelt, Martin G., Nusser, Adi
An excess of sight-lines close to Lyman-break galaxies (LBGs) with little or no absorption in QSO absorption spectra has been reported and has been interpreted as the effect of galactic winds on the...
Expansion and Collapse in the Cosmic Web (2005)
Rauch, Michael, Becker, George D., Viel, Matteo, Sargent, Wallace L. W., Smette, Alain, Simcoe, Robert A., ...
We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological hydrodynamic...
Spatial fluctuations in the spectral shape of the UV background at 2 (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Carswell, Robert F.
The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic HI and HeII Ly-alpha...
Viel, Matteo, Haehnelt, Martin G.
(abridged) The flux power spectrum of the Lyman-alpha forest in quasar (QSO) absorption spectra is sensitive to a wide range of cosmological and astrophysical parameters and instrumental effects....
Viel, Matteo, Haehnelt, Martin G., Springel, Volker
We implement the hydro-PM (HPM) technique (Gnedin & Hui 1998) in the hydrodynamical simulation code GADGET-II and quantify the differences between this approximate method and full hydrodynamical...
Constraints on the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Understanding the sources responsible for reionizing the Universe is a key goal of observational cosmology. A discrepancy has existed between the metagalactic hydrogen ionization rate, Gamma_HI,...
The Lyman alpha forest opacity and the metagalactic hydrogen ionization rate at z~ 2-4 (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Constraints on the meta-galactic hydrogen ionisation rate from the Lyman-α forest opacity (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4 (2004)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Estimates of the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity in QSO absorption spectra depend on the complex density distribution of neutral hydrogen along the...
Viel, Matteo, Haehnelt, Martin G., Springel, Volker
We use the LUQAS sample (Kim et al. 2004), a set of 27 high-resolution and high signal-to-noise QSO absorption spectra at a median redshift of z=2.25, and the data from Croft et al. (2002) at a...
Have we detected one of the sources responsible for an early reionisation of the Universe? (2004)
Ricotti, Massimo, Haehnelt, Martin G., Pettini, Max, Rees, Martin J.
In a recent paper Pell'o et al. have reported a candidate z=10 galaxy, A1835#1916, which was found in a near-infrared survey of the central regions of the gravitational lensing cluster A1835. If this...
Galactic winds and the Lyα forest (2004)
Desjacques, Vincent, Nusser, Adi, Haehnelt, Martin G., Stoehr, Felix
Galactic winds and the Lya forest (2003)
Desjacques, Vincent, Nusser, Adi, Haehnelt, Martin G., Stoehr, Felix
We study the effect of galactic outflows on the Lya forest. The winds are modelled as fully ionised spherical bubbles centered around galactic haloes. The observed flux probability distribution and...
Pieri, Matthew M., Haehnelt, Martin G.
Artificial absorption spectra are used to test a variety of instrumental and physical effects on the pixel correlation technique for the detection of weak OVI absorption. At HI optical depths = 5....
Joint Formation of Supermassive Black Holes and Galaxies (2003)
The tight correlation between black hole mass and velocity dispersion of galactic bulges is strong evidence that the formation of galaxies and supermassive black holes are closely linked. I review...
The hierarchical build-up of galactic bulges should lead to the build-up of present-day supermassive black holes by a mixture of gas accretion and merging of supermassive black holes. The tight...
The Asiago-ESO/RASS QSO Survey. III. Clustering analysis and its theoretical interpretation (2003)
Grazian, Andrea, Negrello, Mattia, Moscardini, Lauro, Cristiani, Stefano, Haehnelt, Martin G., Matarrese, Sabino, ...
This is the third paper of a series describing the Asiago-ESO/RASS QSO survey (AERQS), a project aimed at the construction of an all-sky statistically well-defined sample of relatively bright QSOs (B
Multiple black holes in galactic bulges (2002)
Haehnelt, Martin G., Kauffmann, Guinevere
We study the number and interaction rates of supermassive black holes in galactic bulges as predicted by hierarchical models of galaxy formation in which the spheroidal components of galaxies are...
Kaviani, Ali, Haehnelt, Martin G., Kauffmann, Guinevere
Previous modelling has demonstrated that it is difficult to reproduce the SCUBA source counts within the framework of standard hierarchical structure formation models if the sources are assumed to be...
Feeding black holes at galactic centres by capture from isothermal cusps (2001)
Zhao, HongSheng, Haehnelt, Martin G., Rees, Martin J.
We estimate the rate at which stars are captured by supermassive black holes (BHs) in the centres of bulges and elliptical galaxies assuming that these initially had an isothermal cusp (rho ~ r^{-2}...
An ionizing UV background dominated by massive stars (2000)
Haehnelt, Martin G., Madau, Piero, Kudritzki, Rolf P., Haardt, Francesco
We discuss implications of a stellar-dominated UV background at high redshifts. The composite spectrum of 29 LBGs evaluated by Steidel etal (2000) at =3.4 can be well fit by a stellar population with...
Haehnelt, Martin G., Kauffmann, Guinevere
Recent work has demonstrated that there is a tight correlation between the mass of a black hole and the velocity dispersion of the bulge of its host galaxy. We show that the model of Kauffmann &...
The formation and evolution of supermassive black holes and their host galaxies (1999)
Haehnelt, Martin G., Kauffmann, Guinevere
We discuss constraints on the assembly history of supermassive black holes from the observed remnant black holes in nearby galaxies and from the emission caused by accretion onto these black holes....
Haehnelt, Martin G., Steinmetz, Matthias, Rauch, Michael
We combine predictions for several hierarchical cosmogonies with observational evidence on damped Lyman alpha systems to establish a correspondence between the high redshift galaxy population and the...
Radiative Transfer Effects during Photoheating of the Intergalactic Medium (1999)
Abel, Tom, Haehnelt, Martin G.
The thermal history of the intergalactic medium (IGM) after reionization is to a large extent determined by photoheating. Here we demonstrate that calculations of the photoheating rate which neglect...
The Distribution of Supermassive Black Holes in the Nuclei of Nearby Galaxies (1999)
Andrea Cattaneo, Martin G. Haehnelt, Martin J. Rees
The growth of supermassive black holes by merging and accretion in hierarchical models of galaxy formation is studied by means of Monte Carlo simulations. A tight linear relation between masses of...
Supermassive black holes as sources for LISA (1998)
Some issues relevant for the formation of supermassive black holes are discused and estimates of the event rates for the emission of gravitational waves by coalescing supermassive black hole binaries...
High-redshift galaxies, their active nuclei and central black holes (1997)
Haehnelt, Martin G., Natarajan, Priyamvada, Rees, Martin J.
We demonstrate that the luminosity function of the recently detected population of star-forming galaxies and the QSO luminosity function at z=3 can be matched with the mass function of dark matter...
Probing the thermal history of the Intergalactic Medium with Lyman-alpha absorption lines (1997)
Haehnelt, Martin G., Steinmetz, Matthias
The Doppler parameter distribution of Lyman-alpha absorption is calculated for a set of different reionization histories. The differences in temperature between different reionization histories are...
Damped Lyman alpha absorbers at high redshift -- large disks or galactic building blocks? (1997)
Haehnelt, Martin G., Steinmetz, Matthias, Rauch, Michael
We investigate the nature of the physical structures giving rise to damped Lyman alpha absorption systems (DLAS) at high redshift. In particular, we examine the suggestion that rapidly rotating large...
Rauch, Michael, Haehnelt, Martin G., Steinmetz, Matthias
In hierarchical cosmogonies at redshift three the matter content of a typical present-day galaxy is dispersed over several individual clumps embedded in sheet-like structures, often aligned along...
Non-equilibrium effects on line-of-sight size estimates of QSO absorption systems (1996)
Haehnelt, Martin G., Rauch, Michael, Steinmetz, Matthias
Estimates of the linear extent of heavy-element absorption systems along the line-of-sight to a QSO often assume that the cloud is photoionized and that the temperature takes the equilibrium value...
COBRAS/SAMBA and measurements of the Sunyaev-Zeldovich effect (1996)
The recently approved COBRAS/SAMBA cosmic microwave background mission will also have a major impact on measurements of the Sunyaev-Zeldovich effect. The frequency of three of the channels (150 GHz,...
Metal absorption from galaxies in the process of formation (1996)
In a hierarchical cosmogony present-day galaxies build up by continuous merging of smaller structures. At a redshift of three the matter content of a typical present-day galaxy is split into about...
Are the Lyman alpha forest "clouds" expanding pancakes? (1995)
The large sizes of Lyman alpha ``clouds'' inferred from coincident absorption in the spectrum of close quasar pairs suggests that these are transient flattened structures of small overdensity. It is...
Haehnelt, Martin G., Tegmark, Max
We have investigated the possibility of inferring peculiar velocities for clusters of galaxies from the Doppler shift of scattered cosmic microwave background (CMB) photons. We find that if the core...
Omega_baryon and the Geometry of Intermediate Redshift Lyman alpha Absorption Systems (1995)
Rauch, Michael, Haehnelt, Martin G.
Estimates of Omega_baryon from primordial nucleosynthesis together with standard assumptions about the ionization state of low column density Lyman alpha forest clouds can be used to determine an...
The role of momentum transfer (``radiation pressure'') due to an internal source of ionizing radiation for the formation of baryonic structures is investigated. Fully-ionized self-gravitating gaseous...