AzTEC Survey of the Central Molecular Zone: Data Reduction, Analysis, and Preliminary Results

TL;DR

This paper presents a comprehensive 1.1 mm survey of the Galactic Center's molecular zone, combining multiple data sources to analyze dust properties and monitor Sgr A*'s activity, revealing detailed spatial maps and a notable outburst.

Contribution

It introduces a novel data reduction and analysis method combining multi-instrument data to produce high-resolution dust and gas maps of the CMZ and monitors Sgr A* with unprecedented detail.

Findings

High-resolution maps of dust temperature, density, and spectral index in the CMZ.

Detection of a 140% outburst in Sgr A* on May 9, 2014.

No long-term systematic variability observed in Sgr A* during the monitoring period.

Abstract

We present a large-scale survey of the central molecular zone (CMZ) of our Galaxy, as well as a monitoring program of Sgr A*, with the AzTEC/Large Millimeter Telescope (LMT) in the 1.1 mm continuum. Our 1.1 mm map covers the main body of the CMZ over a field of $1.6 \times 1.1$ deg$^2$ with an angular resolution of $10.5''$ and a depth of 15 mJy/beam. To account for the intensity loss due to the background removal process, we combine this map with lower resolution CSO/Bolocam and \textit{Planck}/HFI data to produce an effective full intensity 1.1 mm continuum map. With this map and existing \textit{Herschel} surveys, we have carried out a comprehensive analysis of the spectral energy distribution (SED) of dust in the CMZ. A key component of this analysis is the implementation of a model-based deconvolution approach, incorporating the Point Spread Functions (PSFs) of the different instruments, and hence recovering a significant amount of spatial information on angular scales larger than $10.5''$. The monitoring of Sgr A* was carried out as part of a worldwide, multi-wavelength campaign when the so-called G2 object was undergoing the pericenter passage around the massive black hole (MBH). Our preliminary results include 1) high-resolution maps of column density, temperature and dust spectral index across the CMZ; 2) a 1.1~mm light curve of Sgr A* showing an outburst of $140\%$ maximum amplitude on 9th May, 2014 but otherwise only stochastic variations of $10\%$ and no systematic long-term change, consistent with other observations.