SgrA* and the central clusterin 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

MBH = 3.61±0.32 mill. MSOL , R0 = 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 sequencestars

Ghez et al. 2003, Eisenhauer et al. 2005

-505

x

-4

0

4

y

-40

4z

-404

x

-404

y

-4

0

4

z

two coeval disks of young stars

clockwise counter-clockwise

OB (I,III)

>63 (12) >55 (17)

WNL+LBV

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. 2005 (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. 2004 ApJL, Eckart et al. 2005

0

4

8

12

0 50 100

S1SgrA*

e

K 16.06.2003 to=4h47m46s (UT)

0

5

10

15

0 50 100

d

K 15.06.2003 to=3h 01m07s (UT)

t-to (min)

dere

dden

ed fl

ux d

ensity

(m

Jy)

0

2

4

0 20 40 60 80 100

July 8th, 2004, to=02

h37

m57

s

t - to (min)

S (mJy)

SgrA* flare variability and evidence for

significant BH spin

0.5x1012

1.5x1012

2.5x1012

3.5x1012

0 0.2 0.4 0.6 0.8 1.0

radius of last stable orbit

a/(GM/c)

Rls

to(M

=3.

59x1

06 Msu

n)

10-7

10-6

10-5

10-4

10-3

10-2

1012

1013

1014

1 10

10-12

10-10

10-8

10-6

10-4

10-2

epicycle

n=1 g-modeacousticoscillation

fundamental dynamical frequencies

for M=3.59x106

Msun

,a=0.52 GM/c

R, precession

Lense-Thirring

orbital

last stable orbit

R(cm)

(H

z)

0

10

20

30

0 0.2 0.4 0.6 0.8 1.0

orbital period at laststable orbit

a/(GM/c)

Tls

to(m

in)

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. 2005

2003

0.01

0.1

1

10

5x10-4 10-3 2x10-3 5x10-3

average flaresJune15/16

average 'quiescent' June 15/July21

S1 June 16

period: 172 min

frequency (Hz)

No

rmal

ized

po

wer

sp

ectr

um

Scargle / Vaughan

1.5

4.5

1.3x1014 1.4x1014 1.5x1014

t-t0 (min)=

35+57+68-0-22-101

July 17th, 2004: t0=3h46m UT

=-3.50.4

frequency (Hz)

-2.5

0

2.5

5.0

7.5

1.2x1014

1.4x1014

1.6x1014

1.8x1014

2.0x1014

t-t0 (min)=60+92+105-0

t-t0 (min)=37+70+116-0

July 15th, 2004: t0=3h 37m UT

=-3.70.9

=-2.20.3

frequency (Hz)

L (

Lsu

n)

t=0 t=116t=60 IR SED of weak flares

SINFONI 2004:Eisenhauer et al. 2005

Summary

• More accurate values for mass and distance of SgrA*:

MBH = 3.61±0.32 mill. MSOL , R0 = 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