Stellar Systems Group

García-Marín, M.; Eckart, A.; Weiss, A.; Witzel, G.; Bremer, M.; Zamaninasab, M.; Schödel, R.; Kunneriath, D.; Sabha, N.; Baganoff, F.; Dovvciak, M.; Duschl, W. J.; Moultaka, J.; Karas, V.; Najarro, F.; Mužić, K.; Straubmeier, C.; Vogel, S. N.; Krips, M.; Wiesemeyer, H.
The Galactic Center: a Window to the Nuclear Environment of Disk Galaxies. Proceedings of a workshop held at Shanghai, China on October 19-23, 2009. Edited by Mark R. Morris, Q. Daniel Wang, and Feng Yuan. San Francisco: Astronomical Society of the Pacific, 2011, p.315
05/2011

ABSTRACT

We study the sub-mm emission of the 37×34 inner pc² of the Galactic Center (GC) region, including the variability of Sgr A^*, the radiative counterpart of the super-massive black hole (˜4×10⁶M_sun) at the GC. Our analysis is based on the 870 μm maps obtained with the LABOCA instrument at APEX in 2008 and 2009. Complementary 850 and 450 μm maps from the SCUBA archive at the JCMT are also used. We are able to estimate the mass, temperature, and spectral index distribution of the most relevant GC regions. We find that the CDN and surroundings are not dominated by thermal emission; their spectral indices can be explained with a combination of dust, synchrotron and free-free emission in different ratios. The sub-mm light curves of Sgr A^* show strong variability with an activity length of 3-6 hours. Coordinated IR observations have shown a delay of about 1.5 hours between NIR and sub-mm activity, which may be explained with an adiabatic expansion model.