Showing papers by "Steven R. Furlanetto published in 2001"
TL;DR: In this paper, the authors model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts, and find that about 5%-20% of the IGM volume is filled by magnetic fields with an energy density 10% to 15% of thermal energy density of a photoionized IGM.
Abstract: Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts. We generically find that by a redshift z ~ 3, about 5%-20% of the IGM volume is filled by magnetic fields with an energy density 10% of the mean thermal energy density of a photoionized IGM (at ~104 K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the field strength observed in these systems without a need for further dynamo amplification. The intergalactic magnetic field could also provide a nonthermal contribution to the pressure of the photoionized gas that may account for the claimed discrepancy between the simulated and observed Doppler width distributions of the Ly? forest.
208 citations
TL;DR: In this article, the authors model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts, and find that about 5-20% of the IGM volume is filled by magnetic fields with an energy density > 10% of mean thermal energy density of a photo-ionized IGM.
Abstract: Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts. We generically find that by a redshift z=3, about 5-20% of the IGM volume is filled by magnetic fields with an energy density >10% of the mean thermal energy density of a photo-ionized IGM (at T=10^4 K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the field strength observed in these systems without a need for further dynamo amplification. The intergalactic magnetic field could also provide a nonthermal contribution to the pressure of the photo-ionized gas that may account for the claimed discrepancy between the simulated and observed Doppler width distributions of the Ly-alpha forest.
163 citations
TL;DR: In this paper, the structure of a wake generated by the motion of a galaxy in the core of an X-ray cluster for dark matter in the highlycollisional and collisionless limits is calculated analytically.
Abstract: We propose to use gravitational wakes as a direct observational probe of the collisional nature of the dark matter. We calculate analytically the structure of a wake generated by the motion of a galaxy in the core of an X-ray cluster for dark matter in the highly-collisional and collisionless limits. We show that the difference between these limits can be recovered from detailed X-ray or weak lensing observations. We also discuss the sizes of sub-halos in these limits. Preliminary X-ray data on the motion of NGC 1404 through the Fornax group disfavors fluid-like dark matter but does not exclude scenarios in which the dark matter is weakly collisional.
5 citations