High resolution observations of cluster of galaxies by Chandra have revealed the existence of an X-ray emitting comet-like galaxy C153 in the core of cluster of galaxies A2125. The galaxy C153 moving fast in the cluster core has a distinct X-ray tail on one side, obviously due to ram pressure stripping, since the galaxy C153 crossed the central region of A2125. The X-ray emitting plasma in the ...

The baryon acoustic oscillations (BAO) prior to recombination should be imprinted onto the 21cm emission background from the epoch of reionization through the underlying density perturbations. Using an analytical approach for both matter power spectrum (CDM+baryons) and reionization process, we demonstrate the BAO induced signatures on the power spectrum of 21cm emission fluctuations. Future lo...

Motivated by the observations on the intra-cluster light (ICL) and intergalactic stellar populations, n-body simulations are used to model the galactic merging events as a goal to investigate the production and distribution of gravitational unbound populations (GUPs). Both the parabolic and hyperbolic mergers are considered and each category includes six models with different relative orientati...

We present a new calculation of the intergalactic γ-ray pair-production absorption coefficient as a function of both energy and redshift. In reexamining this problem, we make use of a new empirially based calculation (as opposed to previous model calculations) of the intergalactic infrared radiation field (IIRF). We find smaller opacities than those given previously (Stecker & De Jager 1997). W...

We study the effects of the ionizing and dissociating photons produced by Pop III objects on the surrounding intergalactic medium. We find that the typical size of a H2 photodissociated region, Rd ≈ 1− 5 kpc, is smaller than the mean distance between sources at z ≈ 20− 30, but larger than the ionized region by a factor depending on the detailed properties of the emission spectrum. This implies ...

Recently Ménard et al. (hereafter MSFR) detected a subtle but systematic change in the mean color of quasars as a function of their projected separation from foreground galaxies, extending to comoving separations of ∼ 10h−1Mpc, which they interpret as a signature of reddening by intergalactic dust. We present theoretical models of this remarkable observation, using smoothed particle hydrodynami...

We present a search for infrared dust emission associated with the Leo cloud, a large intergalactic cloud in the M96 group. Mid-infrared and far-infrared images were obtained with IRAC and MIPS on the Spitzer Space Telescope. Our analysis of these maps is done at each wavelength relative to the Hi spatial distribution. We observe a probable detection at 8 μm and a marginal detection at 24μm ass...