SgrA* and the central cluster in NIR S. Trippe, T. Ott, F. Eisenhauer, T. Paumard, F. Martins, S. Gillessen, R. Genzel, R. Schödel, A. Eckart, T. Alexander, S. Nayakshin

Observations Imaging: NAOS/CONICA Spectroscopy: SINFONI

Tracking SgrA* Eisenhauer et al. 2005, ApJ, in press M BH = 3.61±0.32 mill. M SOL, R 0 = 7.62±0.32 kpc Schödel et al. 2002, 2003, Eisenhauer et al. 2003, Ghez et al. 2003, 2005

Deepening the “paradox of youth”: 0.5” Nearly all S-stars are B main sequence stars Ghez et al. 2003, Eisenhauer et al. 2005

two coeval disks of young stars clockwisecounter- clockwise OB (I,III) >63 (12)>55 (17) WNL+LB V 20 (7) 22 (11) WNE 2.4 (2.4) 2.5 (3.5) WC 15 (6) 20 (10) t=4±1 Myrs for both disks (Meynet 1995) percentages of different early type stars Levin & Beloborodov 2003, Genzel et al. 2003, Paumard et al. 2005, Nayakshin & Cuadra 2005

IRS34W: LBV, not LBV or in between? S. Trippe, F. Martins, T. Ott, T. Paumard, et al (A&A submitted) IRS34W

New flares: April 29, 2004 UT 08:30:04 UT 09:14:25

More flares

short-time variability in infrared flares Genzel et al. 2003, Nature 425, Ghez et al ApJL, Eckart et al. 2005

SgrA* flare variability and evidence for significant BH spin a’=0.52 a’=0.52 (±0.1,±0.07,±0.14) (±0.1,±0.07,±0.14) FFT Genzel et al. 2004, Aschenbach et al. 2004,Benlloch et al. 2001, Scargle 1982, Vaughan 2004, Trippe, Gillessen et al Scargle / Vaughan

t=0 t=116 t=60 IR SED of weak flares SINFONI 2004: Eisenhauer et al. 2005

Summary More accurate values for mass and distance of SgrA*: M BH = 3.61±0.32 mill. M SOL, R 0 = 7.62±0.32 kpc More information on stellar populations and dynamics: star disks, the “paradox of youth”, LBV candidates More NIR SgrA* activity: first NIR spectra of flares, (quasi-)periodicities