======================================================================== G C N E W S * Newsflash * - The Newsletter for Galactic Center Research - gcnews@mpifr-bonn.mpg.de http://www.mpifr-bonn.mpg.de/gcnews ======================================================================== Vol. 14, No. 9 Dec 21, 2001 The preliminary head count for the GC conference in Hawaii (http://www.gemini.edu/science/gc_conf/ ) has already gone up to 72 now which means that we can expect a large crowd. We will give you more information in our next regular newsletter due in January. Recently submitted papers: -------------------------- 1) Millisecond Pulsars as Probes of Mass Segregation in the Galactic Center (Chaname & Gould, ApJ) 2) Shocked molecular gas towards the SNR G359.1-0.5 and the Snake (Lazendic et al., MNRAS) ------------------------------------------------------------------------ Email : jchaname@black.astro.puc.cl Title : Millisecond Pulsars as Probes of Mass Segregation in the Galactic Center Author(s): Julio Chaname and Andrew Gould Institute: Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA Paper : ApJ, submitted EPrint : astro-ph/0112445 Abstract: We propose a simple test for the existence of a cluster of black hole remnants around Sgr A* that is based on a small sample of any type of Galactic Center objects, provided they are substantially less massive than the black holes and constitute part of an old (> 1 Gyr) population. The test relies on the fact that, under the presence of such a cluster of heavy remnants and because of energy equipartition, lower mass objects would be expelled from the central regions and settle into a distribution very different than the cusp expected to be induced by the supermassive black hole alone. We show that with a sample of just 50 objects and using only their angular positions on the sky relative to Sgr A* it is possible to clearly differentiate between a distribution consistent with the presence of the cluster of black holes and a power-law cusp distribution. We argue that millisecond pulsars might currently be the best candidate to perform this test, because of the large uncertainties involved in the age determination of less exotic objects. In addition, by measuring their first and second period derivatives, millisecond pulsars offer the rare opportunity of determining the complete phase space information of the objects. We show that this extra information improves the detection of any mass segregation by about 30%. ------------------------------------------------------------------------ Email : lazendic@head-cfa.harvard.edu Title : Shocked molecular gas towards the SNR G359.1-0.5 and the Snake Author(s): J. S. Lazendic^1,2, M. Wardle^1, M. G. Burton^3, F. Yusef-Zadeh^4, J. B. Whiteoak^2, A. J. Green^1, M. C. B. Ashley^3 Institute: ^1 School of Physics A28, University of Sydney, Sydney NSW 2006, Australia, ^2 Australia Telescope National Facility, CSIRO, PO Box 76, Epping NSW 1710, Australia, ^3 School of Physics, University of New South Wales, Sydney NSW 2052, Australia, ^4 Department of Physics and Astronomy, Northwestern University, Dearborn Observatory, 2131 North Sheridan Road, Evanston,, IL 60201-2900 Paper : MNRAS, in press EPrint : astro-ph/0112410 Abstract: We have found a bar of shocked molecular hydrogen (H2) towards the OH(1720 MHz) maser located at the projected intersection of supernova remnant (SNR) G359.1-0.5 and the nonthermal radio filament, known as the Snake. The H2 bar is well aligned with the SNR shell and almost perpendicular to the Snake. The OH(1720 MHz) maser is located inside the sharp western edge of the H2 emission, which is consistent with the scenario in which the SNR drives a shock into a molecular cloud at that location. The spectral-line profiles of 12CO, HCO+, and CS towards the maser show broad-line absorption, which is absent in the 13C0 spectra and most probably originates from the pre-shock gas. A density gradient is present across the region and is consistent with the passage of the SNR shock while the H2 filament is located at the boundary between the pre-shocked and post-shock regions. ------------------------------------------------------------------------ (Older versions of the Newsflash can be found at the gcnews web-page) ======================================================================== Edited by Angela Cotera Heino Falcke & Sera Markoff (cotera@as.arizona.edu) (hfalcke,smarkoff@mpifr-bonn.mpg.de) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - For Abstract submission please send the (La)Tex file of your paper to gcnews@mpifr-bonn.mpg.de ========================================================================