Sept. 16, 2014, 4 p.m.

LGRT 1033 Lecture Area

Seunghwan Lim

Title : The Nearest Stellar Factory : Suzaku X-ray study on 30 Doradus Abstract : We explored the general properties of the diffuse plasma in the 30 Doradus, using Suzaku observations. Exploiting high spectral resolution and a low and stable instrumental background of Suzaku, we were able to do more reliable investigations on 30 Dor. We found that the four seperate wing-like regions of 30 Dor can be modeled as diffuse thin thermal plasma of ~5*10^6K and share quite similar temperatures and chemical enrichments, which could be originating from one of the stellar population at the center of 30Dor. We also found that, because of different column densities of the regions, the overall properties of the whole region as a single spectra should be explored with a more flexible model. This implies that when we observe a distant diffuse object not to be spatially resolved, the spatial mix of the regions is likely to require more careful modeling in order to constrain the parameters such as abundances properly. We also report energy crisis in 30 Dor and possible flatter powerlaw component around the central region.

Chris Thibodeau

Title: The Effect of Clustering on Recovering Sources in Millimeter Surveys Abstract: Surveys of galaxies in millimeter and submillimeter wavelengths probe the dust emission from star-forming galaxies at redshifts 1 < z < 8, and so allow the study of galaxy formation and evolution across cosmic time. However, galaxy clustering can complicate source identification. In this study, we have created and analysed 0.7-by-0.7-degree simulated maps at 1100 microns convolved with an 8-arcsec telescope beam (AzTEC on the 32m Large Millimeter Telescope). The map is populated using a differential counts model by Béthermin et al. (2011). We find that in the case of strong clustering between the source positions, the 60% and 80% completeness limits are about a factor of two higher in flux than the case where sources are positioned randomly (no clustering). We also find an increase in artificial flux boosting of the sources for a given completeness percent that is about a factor of two higher in the strong clustering case than the no-clustering case. This analysis is useful because it allows us to anticipate confusion and flux boosting as a function of detected source flux of AzTEC at a 32m LMT aperture and correct for them in surveys as appropriate. Lastly, we suggest that these results are robust for maps greater than about 0.16 square degrees.