Indirect Inference for Locally Stationary Models

We propose the use of indirect inference estimation to conduct inference in complex locally stationary models. We develop a local indirect inference algorithm and establish the asymptotic properties of the proposed estimator. Due to the nonparametric nature of locally stationary models, the resulting indirect inference estimator exhibits nonparametric rates of convergence. We validate our methodology with simulation studies in the confines of a locally stationary moving average model and a new locally stationary multiplicative stochastic volatility model. Using this indirect inference methodology and the new locally stationary volatility model, we obtain evidence of non-linear, time-varying volatility trends for monthly returns on several Fama-French portfolios

Resurrection of Traditional Luminosity Evolution Models to Explain Faint Field Galaxies

We explore the nature of the evolution of faint field galaxies by assuming that the local luminosity function is not well defined. We use a non-negative least squares technique to derive a near optimal set of local luminosity functions for different spectral types of galaxies by fitting to the observed optical and near-infrared counts, B-R colors, and redshift distributions for galaxies with 15 < B < 27. We report here the results of using only traditional luminosity evolution (ie. the photometric evolution of stars in a galaxy over time given reasonable assumptions of the form of the star formation history for various galaxy types), and simple galaxy reddening and find excellent fits to the observed data to B = 27. We conclude that models more exotic than traditional luminosity evolution are not yet required to explain existing faint field galaxy data and thus the need for contributions by mergers or new populations of galaxies is at least 5x less than previously estimated.Comment: 9 pages + 1 table + 4 figures; uuencoded tar compressed postscript; to be published in The Astrohysical Journal Letter

The Morphology of 9 Radio-selected Faint Galaxies from deep HST Imaging

Using the HST WFPC2 we perform deep I-band imaging of 9 radio-selected (limit 14 microJanskys at 8.5 GHz) faint galaxies from Roche, Lowenthal and Koo (2002). Two are also observed in V. Six of the galaxies have known redshifs of 0.4<z<1.0. Radial intensity profiles indicate that 7 are disk galaxies and 2 are bulge-dominated. Four of the six with redshifts have a high optical surface brightness compared to typical disk galaxies. Two of the 9 galaxies are in close interacting pairs, another two are very asymmetric and three have large, luminous rings resembling the collisional starburst rings in the Cartwheel galaxy. In most of these galaxies the high radio luminosities are probably the result of interaction-triggered starbursts. The mixture of observed morphologies suggests that enhanced radio luminosities often persist for >0.2 Gyr, to a late stage of the interaction. One of these 9 galaxies may be an exception in that it is a large red elliptical and its strong radio emission is more likely to be from an obscured AGN.Comment: 12 pages, latex, 8 figures, accepted for publication in MNRA

A deep redshift survey of field galaxies. Comments on the reality of the Butcher-Oemler effect

A spectroscopic survey of over 400 field galaxies has been completed in three fields for which we have deep UBVI photographic photometry. The galaxies typically range from B=20 to 22 and possess redshifts z from 0.1 to 0.5 that are often quite spiky in distribution. Little, if any, luminosity evolution is observed up to redshifts z approx 0.5. By such redshifts, however, an unexpectedly large fraction of luminous galaxies has very blue intrinsic colors that suggest extensive star formation; in contrast, the reddest galaxies still have colors that match those of present-day ellipticals

Further empirical evidence of nonlinearity in the us monetary policy rule

Given conflicting results on whether the US monetary policy rule exhibited nonlinearity in the post-war period we employ a new Granger non-causality nonlinearity test and non-parametric procedures to re-examine the issue. Both procedures suggest that the Fed followed a nonlinear Taylor rule with respect to expected inflation and expected output gap prior to 1979 but not post 1982.Taylor rule, nonlinearity, Granger non-causality nonlinearity, non-parametric