Did the Galactic Center Have an Active or a Starburst Nucleus in the Past?

Previous abstract Next abstract

Session 64 -- Low Luminosity AGNs and Active Galaxies
Oral presentation, Thursday, 2, 1994, 10:00-11:30

[64.08] Did the Galactic Center Have an Active or a Starburst Nucleus in the Past?

Leonid M. Ozernoy (Phys. Dept. and Comp. Sci. \& Inform. Inst., GMU also Lab. for Astr. and Sol. Phys., NASA/GSFC)

Since there is a piece of evidence that both AGN and starburst phenomena are recurrent, an intriguing question arises as to whether the nucleus of the Milky Way Galaxy was active or starbursting (or both) in its past. The present paper aimes at addressing this issue. To this end, two essentially different approaches are undertaken: First, available methods of evaluating or constraining the mass of a putative black hole at the Galactic center are critically reviewed. The derived upper limits turn out to be too small to allow the black hole to serve as an `engine' for a Seyfert galaxy. The main reason why our Galaxy is not a Seyfert one appears to be the lack of a proper `engine' rather than an insufficient mass supply. Second, analyses of recent data on the 10 KeV gas in the central 200 pc and on star formation history at the Galactic center both make a starburst the likely episode in a not too distant past. Taken together, the two approaches indicate that (i) the Galactic nucleus does not seem to be a prototype for activity in galactic nuclei; (ii) a recent starburst at the Galactic center has neither resulted from, nor was induced by, a supermassive black hole; and (iii) rather than being a `dormant' version of AGN, the Galactic nucleus is a scaled-down version of starburst nuclei.

Thursday program listing