SgrA*: Recent NIR/X-ray SgrA*: Recent NIR/X-ray Measurements & the First Time-Measurements & the First Time-Resolved AO NIR Polarization Resolved AO NIR Polarization

MeasurementsMeasurements 26th Genaral Assembly of the IAU26th Genaral Assembly of the IAU

Prague , Czech Republic, August 14-25, 2006 Prague , Czech Republic, August 14-25, 2006

Andreas EckartAndreas Eckart I.Physikalisches Institut der Universität zu Köln I.Physikalisches Institut der Universität zu Köln

Simultaneous NIR / X-rayMeasurements of Flares

from Sgr A* in2003 and 2004

X-Ray/NIR Variability

Eckart, Baganoff, Morris, Bautz, Brandt, Garmire, Genzel, Ott, Ricker, Straubmeier, Viehmann, Schödel, Bower, and Goldston 2004 A&A 427, 1

Chandra + NACO/VLT June 20, 2003

SgrA*: First Simultaneous K-band/X-ray Observations

Simultaneous Flare Emission

Flare emission originates towithin <10mas form the position of SgrA*

2003 data: Eckart, Baganoff, Morris, Bautz, Brandt, et al. 2004 A&A 427, 1 2004 data: Eckart, Morris, Baganoff, Bower, Marrone et al. 2006 A&A 450, 535

see also Yusef-Zadeh, et al. ApJ 644, 198

2004

~6mJy

~225nJy

2/I and4/IV are dominatedby a decaying flank;3/III is domainated by a rising flare flank.

Time lags are less <10-15 minutes

NIR and X-ray flares are well correlated.

Table of Exemplary Models

asR kpcS 8~8@,

S

at ~1 THzMIR/NIR synchr. cutoff at or below NIR

m

2

SSC model

GB

oo

e

50

)4510(

0.23.1

0.22.1

10~ 3

11

2/12

2/12

)cos1(

)1(

)1(

bulk

bulkbulk

ee

Radio: Zhao, Falcke, Bower, Aitken, et al. 1999-2003 X-ray: Baganoff et al. 2001, 2003, Goldwurm et al. 2003, Porquet et al. 2003,NIR: Genzel et al. 2003, Ghez et al. 2003, Eisenhauer et al. 2005, Gillessen et al. 2006models: Markoff, Falcke, Liu, Melia, Narayan, Quataert, Yuan et al. 1999-2001

mm/sub-mm Monitoring in 2004

Eckart, Baganoff, Morris, Bower, Marrone et al. 2006 A&A 427, 1

Indication for decaying flux density at0.7 and 7 mm follwing an X-ray flare – consistent with adiabatic expansion VLA

SMA

see also Yusef-Zadeh et al. 2006 ApJ astro/ph 0603685upcoming talk by Mark Morris

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a

Genzel, Schödel, Ott et al. 2003, Nature 425, 934

QPOs in SgrA* Flare Emission2003, 16 June

A total of 5 flares showssignificantsub-structure:

sub-flares

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a

2003, 16 June QPOs in SgrA* Flare Emission

5

Power law fitfollowing themothode byVaughan (2005)

18+-2 min

red noise

bias corrected significance: 4.2

Lomb-ScarglePeriodogram

Polarized NIR Flaresfrom SgrA* in

2004, 2005 and 2006

Eckart, Schödel, Meyer, Ott, Trippe, Genzel 2006 A&A, 455,1

Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a

NIR Polarized Flux Density from SgrA*

July 2005: VLT NACO Wollaston prism plus retarder wave-plate

mean flux at 0 and 90 degree differential flux between 90 and 0 degree

Eckart, Schödel, Meyer, Trippe, Ott, Genzel 2006, 455, 1

NIR Polarized Flux Density from SgrA*

VLT NACOWollaston prism plusretarder wave-plate

Eckart, Schödel, Meyer, Trippe, Ott, Genzel 2006, 455, 1

2004

NIR Polarized Flux Density from SgrA*

VLT NACOWollaston prism plusretarder wave-plate

Eckart, Schödel, Meyer Trippe, Ott, Genzel 2006, 455, 1

0

90

2005

NIR Polarized Flux Density from SgrA*

VLT NACOWollaston prism plusretarder wave-plate

Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b

2006

polarized sub-flares

NIR Polarized Flux Density from SgrA*

2006

no significantred noise

Lomb-Scargle Periodograms

Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b

2005

Signifiant excess power in the variability of SgrA* at

2005: 18+-3 min

2006: 15+-2 min

Eckart, Schödel, Meyer,Trippe, Ott, Genzel 2006, 455, 1

A jet or wind emerging from SgrA* ?

The central 0.5x0.5 square parsec

at 3.8 m.

PA of E-vector with respect to

prominent structures

flare phase:2004, 2005: 60+/-20 2006: 80+/-10

Eckart, Schödel, Meyer, Ott, Trippe, Genzel 2006 A&A, 455, 1

see also poster by K. Muzic: S238-140

and following talk byRainer Schödel

Radiation from aTemporal Accretion Disk

NIR Polarized Flux Density from SgrA*

Goldston, Quataert & Igumenshchev 2005, ApJ 621, 785

see also Broderick & Loeb 2005 astro-ph/0509237 Broderick & Loeb 2005 astro-ph/0506433

Dovciak, Karas & Yaqoob 2004, ApJS 153, 205Dovciak et al. 2006 ~4min prograde

~30min static~60min retrogradefor 3.6x10**6Msol

NIR Polarized Flux Density from SgrA*

Hot Spot Model

Eckart, Schödel, Meyer, Ott, Trippe, Genzel 2006 A&A, 455, 1

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a

Dovciak, Karas & Yaqoob 2004, ApJS 153, 205

Case II: toroidal B-fieldCase I: E-vector perp. to disk

see also poster by L. Meyer: S238-135

Blandford , 2002 in Lighthouses of the Universe Hirose, Krolik, De Villiers, Hawley 2004, ApJ 606, 1083

What Magnetic Fields Can Do

Case II toroidal B-field / Case I E-vector perp. to disk Hot Spot Model

Case I: i=70, a/M=0.998 = 70

Case II: i=10, a/M=0.998 =40

Spot close to 4.5 Rg

Degree of polarization does not necessarily have to be explained by a ‚simple‘ hot spot model!Spot may have influence on thesurrounding disk and polarize it.

Independent of inclination:The signature for a possiblehigh spin value is persistent!

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a

Hot Spot Model

E-vector perp. to disk

i=58, a/M~1.0, = 80Spot close to 4.0 Rg

Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b

ConclusionSimultaneous radio/NIR/X-ray

andNIR polarization measurements

are ideal tools to study theaccretion onto SgrA*

Inerferometric measurements in the radio and NIR/MIRInerferometric measurements in the radio and NIR/MIRcombined with results from other wavelength domainscombined with results from other wavelength domains

are ideally suited for future investigations

LBT LINC/NIRVANALBT NIR/OPT Beam Combiner(Herbst et al. 2003):MPIA, HeidelbergUniversitity of CologneOsservatorio Astrofisico di ArcetriMPIfR Bonn

GRAVITYVLTI NIR/OPT Beam Combiner(Eisenhauer et al. 20006):MPE, Paris-Medoun, MPIA, CologneINFRASTRUCTURE:MPE – STS3Clogone – STS4