SgrA*: Recent NIR/X-ray Measurements & the First Time- Resolved AO NIR Polarization Measurements 26th Genaral Assembly of the IAU Prague, Czech Republic, August 14-25, 2006 Andreas Eckart I.Physikalisches Institut der Universität zu Köln

Simultaneous NIR / X-ray Measurements of Flares from Sgr A* in 2003 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 to within <10mas form the position of SgrA* 2003 data: Eckart, Baganoff, Morris, Bautz, Brandt, et al A&A 427, data: Eckart, Morris, Baganoff, Bower, Marrone et al A&A 450, 535 see also Yusef-Zadeh, et al. ApJ 644, ~6mJy ~225nJy  2/I and  4/IV are dominated by 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 S at ~1 THz MIR/NIR synchr. cutoff at or below NIR m 2 SSC model Radio: Zhao, Falcke, Bower, Aitken, et al 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 models: Markoff, Falcke, Liu, Melia, Narayan, Quataert, Yuan et al

mm/sub-mm Monitoring in 2004 Eckart, Baganoff, Morris, Bower, Marrone et al A&A 427, 1 Indication for decaying flux density at 0.7 and 7 mm follwing an X-ray flare – consistent with adiabatic expansion VLA SMA see also Yusef-Zadeh et al ApJ astro/ph upcoming 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 Emission 2003, 16 June A total of 5 flares shows significant sub-structure: sub-flares

Meyer, Eckart, Schödel, Duschl, Muzic, Dovciak, Karas 2006a 2003, 16 June QPOs in SgrA* Flare Emission 5     Power law fit following the mothode by Vaughan (2005) min red noise bias corrected significance: 4.2  Lomb-Scargle Periodogram

Polarized NIR Flares from 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 NACO Wollaston prism plus retarder wave-plate Eckart, Schödel, Meyer, Trippe, Ott, Genzel 2006, 455,

NIR Polarized Flux Density from SgrA* VLT NACO Wollaston prism plus retarder wave-plate Eckart, Schödel, Meyer Trippe, Ott, Genzel 2006, 455,

NIR Polarized Flux Density from SgrA* VLT NACO Wollaston prism plus retarder wave-plate Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b 2006 polarized sub-flares

NIR Polarized Flux Density from SgrA* 2006 no significant red noise Lomb-Scargle Periodograms Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b 2005 Signifiant excess power in the variability of SgrA* at 2005: min 2006: 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+/ : 80+/-10 Eckart, Schödel, Meyer, Ott, Trippe, Genzel 2006 A&A, 455, 1 see also poster by K. Muzic: S and following talk by Rainer Schödel

Radiation from a Temporal Accretion Disk

NIR Polarized Flux Density from SgrA* Goldston, Quataert & Igumenshchev 2005, ApJ 621, 785 see also Broderick & Loeb 2005 astro-ph/ Broderick & Loeb 2005 astro-ph/ Dovciak, Karas & Yaqoob 2004, ApJS 153, 205 Dovciak et al ~4min prograde ~30min static ~60min retrograde for 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-field Case I: E-vector perp. to disk see also poster by L. Meyer: S 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 the surrounding disk and polarize it. Independent of inclination: The signature for a possible high 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,  = 80 Spot close to 4.0 Rg Meyer, Schödel, Eckart, Karas, Dovciak, Duschl 2006b

Conclusion Simultaneous radio/NIR/X-ray and NIR polarization measurements are ideal tools to study the accretion onto SgrA* Inerferometric measurements in the radio and NIR/MIR combined with results from other wavelength domains are ideally suited for future investigations LBT LINC/NIRVANA LBT NIR/OPT Beam Combiner (Herbst et al. 2003): MPIA, Heidelberg Universitity of Cologne Osservatorio Astrofisico di Arcetri MPIfR Bonn GRAVITY VLTI NIR/OPT Beam Combiner (Eisenhauer et al ): MPE, Paris-Medoun, MPIA, Cologne INFRASTRUCTURE: MPE – STS3 Clogone – STS4