The contribution of starbursts and normal galaxies to infrared luminosity functions at z < 2

We present a parameter-less approach to predict the shape of the infrared (IR) luminosity function (LF) at redshifts z < 2. It requires no tuning and relies on only three observables: (1) the redshift evolution of the stellar mass function for star-forming galaxies, (2) the evolution of the specific star formation rate (sSFR) of main-sequence galaxies, and (3) the double-Gaussian decomposition of the sSFR-distribution at fixed stellar mass into a contribution (assumed redshift- and mass-invariant) from main-sequence and starburst activity. This self-consistent and simple framework provides a powerful tool for predicting cosmological observables: observed IR LFs are successfully matched at all z < 2, suggesting a constant or only weakly redshift-dependent contribution (8-14%) of starbursts to the star formation rate density. We separate the contributions of main-sequence and starburst activity to the global IR LF at all redshifts. The luminosity threshold above which the starburst component dominates the IR LF rises from log(LIR/Lsun) = 11.4 to 12.8 over 0 < z < 2, reflecting our assumed (1+z)^2.8-evolution of sSFR in main-sequence galaxies.Comment: 7 pages, 4 figures & 1 table. Accepted for publication in ApJL. Minor typos corrected in v2 following receipt of proof

Estimating the Displacement on the Norumbega Fault System Using Quartz Microstructures

The Sandhill Corner shear zone is the longest continuous strand of deformation within the Norumbega Fault System (NFS). The Norumbega is a dextral fault system that extends from New Hampshire into New Brunswick. This study uses recrystallized grain size piezometry and quartz flow laws to determine the total offset on the Sandhill Corner shear zone (SCsz). Recrystallized quartz grains were measured and quartz crystallographic preferred orientations (CPO) were determined in three samples using SEM-EBSD. Differential stress and deformation temperature can be estimated from these data and then used to calculate strain rate and total shear zone offset. Calculating the quartz c-axis fabrics made it possible to determine the deformation temperature, these temperatures ranged from 400±50ºc to 500±50ºc. Differential stress ranged between 47.5-60.1MPa, the strain rate ranged between 1.44x10-13s-1 and 3.73x10-13s-1 and the plate velocity estimates were between 0.45-1.18cm/year. Previous estimates of the total displacement across the Norumbega fault system and the Sandhill Corner shear zone range widely, from 25-1900km. Based on a previously well-established regional cooling history there was significant plate movement during a 30-million-year period. Based on deformation temperature and published Ar-Ar dating, it was possible to estimate that this shear zone was deforming between 370 million years ago to 340 million years ago. It was possible to get an estimated total distance of displacement between 136-353k

The mechanism of double exponential growth in hyper-inflation

Analyzing historical data of price indices we find an extraordinary growth phenomenon in several examples of hyper-inflation in which price changes are approximated nicely by double-exponential functions of time. In order to explain such behavior we introduce the general coarse-graining technique in physics, the Monte Carlo renormalization group method, to the price dynamics. Starting from a microscopic stochastic equation describing dealers' actions in open markets we obtain a macroscopic noiseless equation of price consistent with the observation. The effect of auto-catalytic shortening of characteristic time caused by mob psychology is shown to be responsible for the double-exponential behavior.Comment: 9 pages, 5 figures and 2 tables, submitted to Physica

Interferometric CO observations of the ultraluminous IRAS galaxies ARP 220, IC 694/NGC 3690, NGC 6420 and NGC 7469

High resolution CO observations of the IRAS galaxies Arp 220, IC 694/NGC 3690, NGC 6240 and NGC 7469 were made with the Millimeter Wave Interferometer of the Owen Valley Radio Observatory. These yield spatial information on scales of 1 to 5 kpc and allow the separation of compact condensations from the more extended emission in the galaxies. In the case of the obviously interacting system IC 694/NGC 3690 the contributions of each component can be discerned. For that galaxy, and also for Arp 220, the unusually high lumonisities may be produced by nonthermal processes rather than by intense bursts of star formation

Falloff of the Weyl scalars in binary black hole spacetimes

The peeling theorem of general relativity predicts that the Weyl curvature scalars Psi_n (n=0...4), when constructed from a suitable null tetrad in an asymptotically flat spacetime, fall off asymptotically as r^(n-5) along outgoing radial null geodesics. This leads to the interpretation of Psi_4 as outgoing gravitational radiation at large distances from the source. We have performed numerical simulations in full general relativity of a binary black hole inspiral and merger, and have computed the Weyl scalars in the standard tetrad used in numerical relativity. In contrast with previous results, we observe that all the Weyl scalars fall off according to the predictions of the theorem.Comment: 7 pages, 3 figures, published versio

Constraining reionization using the thermal history of the baryons

The thermal evolution of the intergalactic medium (IGM) depends on the reionization history of the universe. Numerical simulations indicate that the low density IGM, which is responsible for the low column density Ly-alpha forest, follows a well defined temperature-density relation. This results in a cut-off in the distribution of line widths as a function of column density. We use hydrodynamic simulations to calibrate the relation between the cut-off and the temperature-density relation and apply this relation to Keck spectra spanning a redshift range z=2-4.5. We find that the temperature peaks at z~3 and interpret this as evidence for reheating due to the reionization of helium.Comment: 4 pages, 2 figures, to appear in "Cosmic evolution and galaxy formation: Structure, interactions, and feedback", eds. J. Franco et a

Ultraslow light in inhomogeneously broadened media

We calculate the characteristics of ultraslow light in an inhomogeneously broadened medium. We present analytical and numerical results for the group delay as a function of power of the propagating pulse. We apply these results to explain the recently reported saturation behavior [Baldit {\it et al.}, \prl {\bf 95}, 143601 (2005)] of ultraslow light in rare earth ion doped crystal.Comment: 4 pages, 5 figure