On The Validity of the Streaming Model for the Redshift-Space Correlation Function in the Linear Regime

The relation between the galaxy correlation function in real and redshift-space is derived in the linear regime by an appropriate averaging of the joint probability distribution of density and velocity. The derivation recovers the familiar linear theory result on large scales but has the advantage of clearly revealing the dependence of the redshift distortions on the underlying peculiar velocity field; streaming motions give rise to distortions of ${\cal O}(\Omega^{0.6}/b)$ while variations in the anisotropic velocity dispersion yield terms of order ${\cal O}(\Omega^{1.2}/b^2)$. This probabilistic derivation of the redshift-space correlation function is similar in spirit to the derivation of the commonly used ``streaming'' model, in which the distortions are given by a convolution of the real-space correlation function with a velocity distribution function. The streaming model is often used to model the redshift-space correlation function on small, highly non-linear, scales. There have been claims in the literature, however, that the streaming model is not valid in the linear regime. Our analysis confirms this claim, but we show that the streaming model can be made consistent with linear theory {\it provided} that the model for the streaming has the functional form predicted by linear theory and that velocity distribution is chosen to be a Gaussian with the correct linear theory dispersion.Comment: 14 pages, no figures, uuencoded compressed postscrip

Tandberg Elice (Sanako Lab 100) System

A review of the Tandberg Elice (Sanako Lab 100) system. TheElice is a virtual cassette lab with one computer for theteacher and a virtual cassette deck for each student. Thesystem is especially attractive for institutions that administerAP language exams

Foundation and Development of the Economic Interest of the United States in the Arctic Ocean in the Age of Global Warming

The United States’ sustained economic and geopolitical interest in the Arctic is dependent on Congressional funding and Executive support for icebreaking vessels and improved infrastructure in United States Arctic territory. The United States has an interest in the Arctic, which is demonstrated by The Arctic Research and Policy Act of 1984 (amended 1990). Through the Act, the United States initiated research and policy development with the supposition of potential economic benefits in the future. Due to verifiable and anticipated changes in ice density in the Arctic, the region is accessible like never before and international competition for natural resources and commercial shipping lanes in the Arctic offer newfound economic benefits. The United States is woefully behind its international competitors due to a small and decrepit fleet of icebreaking vessels and crumbling infrastructure in the Arctic. In examining The Arctic Research and Policy Act of 1984 and multiple Arctic Strategy Plans that were published by federal agencies operating in the Arctic, it is clear that attention from Congress and the Executive must be redirected towards advancement. The first step to advancing the United States interest in the Arctic is by funding and procuring icebreaking vessels and improving Arctic territory infrastructure

Galaxy Clustering Around Nearby Luminous Quasars

We examine the clustering of galaxies around a sample of 20 luminous low redshift (z<0.30) quasars observed with the Wide Field Camera-2 on the Hubble Space Telescope. The HST resolution makes possible galaxy identification brighter than V=23.5 and as close as 2'' to the quasar. We find a significant enhancement of galaxies within a projected separation of < 100 kpc/h of the quasars. If we model the qso/galaxy correlation function as a power law with a slope given by the galaxy/galaxy correlation function, we find that the ratio of the qso/galaxy to galaxy/galaxy correlation functions is $3.8\pm 0.8$. The galaxy counts within r<15 kpc/h of the quasars are too high for the density profile to have an appreciable core radius ( > 100 kpc). Our results reinforce the idea that low redshift quasars are located preferentially in groups of 10-20 galaxies rather than in rich clusters. We see no significant difference in the clustering amplitudes derived from radio-loud and radio-quiet subsamples.Comment: 16 pages, 3 figures (included), 2 tables, Apj in pres

The IRAS 1.2 Jy Survey: Redshift Data

We present the redshift data for a survey of galaxies selected from the data base of the Infrared Astronomical Satellite (IRAS). This survey extends the 1.936 Jy sample of Strauss et al. (1992) from a flux limit of 1.936 Jy at 60 microns to 1.2 Jy. The survey extension consists of 3920 sources in the flux interval 1.2 - 1.936 Jy, of which 2663 are galaxies with measured redshifts. Fourteen objects (0.52%) do not have redshifts. The survey covers 87.6% of the sky. The data for the complete 1.2 Jy survey (the data presented here in addition to that of Strauss \etal 1992) may be obtained in a machine-readable form from the National Space Science Data Center and from the anonymous ftp site given above.Comment: uuencoded postscript file. Figures, data tables, and machine readable data files can be obtained via anonymous ftp to (192.16.204.30) ftp://eku.ias.edu/pub/fisher/12jy/12jy.tar.Z (a compressed tar file)