S. Stolovy1, F. Melia2, D. McCarthy 2, F. Yusef-Zadeh 3
1 SIRTF Science Center, CalTech, MS 220-6,
Pasadena, CA 91125, USA
2 Steward Observatory, University of Arizona, Tucson, AZ 85721
3 Northwestern University, Evanston, IL 60208
E-mail contact: firstname.lastname@example.org
Images of the central arcsecond of the Galaxy at near infrared wavelengths reveal a tight stellar cluster, however, no point source exactly coincident with the radio source Sgr A* has been clearly detected. ``Contaminating'' emission due to overlapping point spread functions (PSFs) from this stellar cluster as well as from the bright IRS16 sources 1-3 arcsec away from Sgr A* makes it difficult to assess directly the near-IR characteristics of Sgr A*. Taking advantage of the stability of the PSF acheived by HST/NICMOS observations, we employ PSF subtraction techniques in order to investigate the true nature of the near-infrared emission from Sgr A*. New limits on the maximum possible flux emanating from a point source coincident with Sgr A* are presented at 1.1, 1.45, 1.6, 1.9, and 2.2 microns based on NICMOS data taken at several epochs. The resulting extinction-corrected fluxes are compared to theoretical models (including both quiescent and flare models) for the spectrum of Sgr A*. We also present NICMOS narrow-band emission line images in Pa, where significant stellar residuals have been removed to reveal new diffuse structures in the ionized gas near Sgr A*.