Another aspect of my work is related to one of the most common problems in astrophysics, i.e. the classification of astronomical sources based on their colors and magnitudes. Currently, I am strongly involved on the classification of ~6M infrared point sources in the Large Magellanic Cloud detected with the Spitzer Space Telescope.
The question is obvious: Can we reliably classify all these sources? For this reason, we use a statistical approach based on the weighted k-Nearest Neighbors (k-NN) method (following Marengo & Sanchez 2009, AJ, 138, 63), which has been successfully used as an efficient “black box” predictor for problems of pattern recognition and unsupervised machine learning. A metric is defined in a multi-dimensional color-magnitude space, based only on the photometric properties of template sources and the photometric uncertainties of both templates and data, as a function of the k-NN number and a threshold distance Dth.
⎔ Antoniou, V. & Zezas, A. 2012, Star Formation History and X-ray Binary Populations: The Case of the Large Magellanic Cloud, ApJ subm.
⎔ Woods, P. M., Oliveira, J. M., Kemper, F., and 54 coauthors 2011, The SAGE-Spec Spitzer Legacy program: The life-cycle of dust and gas in the Large Magellanic Cloud. Point Source classification, MNRAS, 411, 1597
⎔ Antoniou, V., Zezas, A., Hatzidimitriou, D. & Kalogera, V. 2010, Star Formation History and X-ray Binary Populations: The Case of the Small Magellanic Cloud, ApJL, 716, 140
⎔ Laycock, S., Zezas, A., Hong, J., Drake, J. J., Antoniou, V. 2010, Exploring the Small Magellanic Cloud to the Faintest X-ray Fluxes: Source Catalog, Timing, and Spectral Analysis, ApJ, 716, 1217
⎔ Kemper, F., Woods, P. M., Antoniou, V., and 53 coauthors 2010, The SAGE-Spec Spitzer Legacy Program: The Life Cycle of Dust and Gas in the Large Magellanic Cloud, PASP, 122, 683
⎔ Antoniou, V., Hatzidimitriou, D., Zezas, A., & Reig, P. 2009, Optical spectroscopy of 20 Be/X-ray Binaries in the Small Magellanic Cloud, ApJ, 707, 1080
⎔ Antoniou, V., Zezas, A., Hatzidimitriou, D. & McDowell, J. 2009, The Chandra survey of the SMC ``Bar": II. Optical counterparts of X-ray sources, ApJ, 697, 1695