The Central Molecular Zone (CMZ) of our Galaxy hosts an extreme environment analogous to that found in typical starburst galaxies in the distant universe. In order to understand dust properties in environments like our CMZ, we present results from a
joint SED analysis of our AzTEC/Large Millimeter Telescope survey, together with existing textit{Herschel} far-IR data on the CMZ, from a wavelength range of $160$ $mu m$ to $1.1$ $mm$. We include global foreground and background contributions in a novel Bayesian modeling that incorporates the Point Spread Functions (PSFs) of the different maps, which enables the full utilization of our high resolution ($10.5$) map at 1.1 $mm$ and reveals unprecedentedly detailed information on the spatial distribution of dusty gas across the CMZ. There is a remarkable trend of increasing dust spectral index $beta$, from $2.0-2.4$, toward dense peaks in the CMZ, indicating a deficiency of large grains or a fundamental change in dust optical properties. This environmental dependence of $beta$ could have a significant impact on the determination of dust temperature in other studies. Depending on how the optical properties of dust deviate from the conventional model, dust temperatures could be underestimated by $10-50%$ in particularly dense regions.
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.
We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer IRAC colors as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and SMA-confirmed counterparts
to AzTEC sources across three fields (GOODS-N, GOODS-S, and COSMOS), we develop a non-parametric IRAC color-color characteristic density distribution (CDD), which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around SMGs and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beamsize (~18), this technique identifies ~85 per cent of SMG counterparts. For much larger beamsizes (>30), we report identification rates of 33-49 per cent. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the LMT and SCUBA-2 on JCMT.
