Exact Likelihood Inference and Robust Filtering for Gauss-Cauchy Convolution Models

Fuente: arXiv
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Main Authors: Hansen, Peter Reinhard, Tong, Chen
Format: Preprint
Published: 2026
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author Hansen, Peter Reinhard
Tong, Chen
author_facet Hansen, Peter Reinhard
Tong, Chen
contents The convolution of a Gaussian and a Cauchy distribution, known as the Voigt distribution, is widely used in spectroscopy and provides a natural framework for modeling heavy-tailed measurement noise. We derive analytical expressions for its density, score, Hessian, Fisher information, and conditional moments using the scaled complementary error function, enabling stable maximum likelihood estimation without numerical convolution, finite-difference derivatives, or pseudo-Voigt approximations. The conditional expectation of the latent Gaussian component is governed by a redescending location score, so extreme observations are automatically discounted rather than propagated. This structure leads to the Gauss-Cauchy Convolution (GCC) filter for state-space models with Gaussian latent dynamics and Voigt measurement errors, where the Masreliez Gaussian prediction approximation preserves a Voigt prediction-error density. In an application to log realized volatility for the Technology Select Sector SPDR Fund, the GCC filter separates persistent latent variation from transient measurement noise and attains the highest implemented prediction-error criterion among the Gaussian, Student-$t$, Huber, and related filtering specifications considered.
format Preprint
id arxiv_https___arxiv_org_abs_2605_01665
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Exact Likelihood Inference and Robust Filtering for Gauss-Cauchy Convolution Models
Hansen, Peter Reinhard
Tong, Chen
Econometrics
Methodology
The convolution of a Gaussian and a Cauchy distribution, known as the Voigt distribution, is widely used in spectroscopy and provides a natural framework for modeling heavy-tailed measurement noise. We derive analytical expressions for its density, score, Hessian, Fisher information, and conditional moments using the scaled complementary error function, enabling stable maximum likelihood estimation without numerical convolution, finite-difference derivatives, or pseudo-Voigt approximations. The conditional expectation of the latent Gaussian component is governed by a redescending location score, so extreme observations are automatically discounted rather than propagated. This structure leads to the Gauss-Cauchy Convolution (GCC) filter for state-space models with Gaussian latent dynamics and Voigt measurement errors, where the Masreliez Gaussian prediction approximation preserves a Voigt prediction-error density. In an application to log realized volatility for the Technology Select Sector SPDR Fund, the GCC filter separates persistent latent variation from transient measurement noise and attains the highest implemented prediction-error criterion among the Gaussian, Student-$t$, Huber, and related filtering specifications considered.
title Exact Likelihood Inference and Robust Filtering for Gauss-Cauchy Convolution Models
topic Econometrics
Methodology
url https://arxiv.org/abs/2605.01665