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