Power Spectrum Analysis of the OMC1 Image at 1.1 mm Wavelength

TL;DR

This paper analyzes the spatial structure of the OMC1 region at 1.1 mm wavelength using power spectrum analysis, revealing multiple components and scale-dependent behaviors consistent with numerical simulations.

Contribution

It introduces a detailed power spectrum analysis of 1.1mm emission from OMC1, accounting for beam size and noise effects, and identifies multiple power-law components in the structure.

Findings

Power spectrum steepens at smaller scales.

At larger scales, the spectrum flattens and becomes shallower.

The best-fit power law slope is approximately -2.7, similar to simulations.

Abstract

We present a 1.1mm emission map of the OMC1 region observed with AzTEC, a new large-format array composed of 144 silicon-nitride micromesh bolometers, that was in use at the James Clerk Maxwell Telescope (JCMT). These AzTEC observations reveal dozens of cloud cores and a tail of filaments in a manner that is almost identical to the submillimeter continuum emission of the entire OMC1 region at 450 and 850 micronm. We perform Fourier analysis of the image with a modified periodogram and the density power spectrum, which provides the distribution of the length scale of the structures, is determined. The expected value of the periodogram converges to the resulting power spectrum in the mean squared sense. The present analysis reveals that the power spectrum steepens at relatively smaller scales. At larger scales, the spectrum flattens and the power law becomes shallower. The power spectra of the 1.1mm emission show clear deviations from a single power law. We find that at least three components of power law might be fitted to the calculated power spectrum of the 1.1mm emission. The slope of the best fit power law, \gamma ~ -2.7 is similar to those values found in numerical simulations. The effects of beam size and the noise spectrum on the shape and slope of the power spectrum are also included in the present analysis. The slope of the power law changes significantly at higher spatial frequency as the beam size increases.