Polarized NIR and X-ray Flares from SgrA*

Abstract

Stellar dynamics indicate the presence of a super massive 3-4x10^6 Msun solm black hole at the Galactic Center. It is associated with the variable radio, near-infrared, and X-ray counterpart Sagittarius A* (SgrA*). The goal is the investigation and understanding of the physical processes responsible for the variable emission from SgrA*. The observations have been carried out using the NACO adaptive optics (AO) instrument at the European Southern Observatory's Very Large Telescope (July 2005, May 2007) and the ACIS-I instrument aboard the Chandra X-ray Observatory (July 2005). We find that for the July 2005 flare the variable and polarized NIR emission of SgrA* occurred synchronous with a moderately bright flare event in the X-ray domain with an excess 2 - 8 keV luminosity of about 8x10^33erg/s. We find no time lag between the flare events in the two wavelength bands with a lower limit of less than 10 minutes. The May 2007 flare shows the highest sub-flare to flare contrast observed until now. It provides evidence for a variation in the profile of consecutive sub-flares. We confirm that highly variable and NIR polarized flare emission is non-thermal and that there exists a class of synchronous NIR/X-ray flares. We find that the flaring state can be explained via the synchrotron self-Compton (SSC) process involving up-scattered sub-millimeter photons from a compact source component. The observations can be interpreted in a model involving a temporary disk with a short jet. In the disk component the flux density variations can be explained due to spots on relativistic orbits around the central super massive black hole (SMBH). The profile variations for the May 2007 flare are interpreted as a variation of the spot structure due to differential rotation within the disk.

16 pages, 18 figures. A&A in press, minor final corrections included

References in corpus (57)

• Closest Star Seen Orbiting the Supermassive Black Hole at the Centre of the Milky Way
• Stellar Orbits Around the Galactic Center Black Hole
• The Proper Motion of Sgr A*: II. The Mass of Sgr A*
• Chandra X-ray Spectroscopic Imaging of Sgr A* and the Central Parsec of the Galaxy
• High Proper Motion Stars in the Vicinity of Sgr A*: Evidence for a Supermassive Black Hole at the Center of Our Galaxy
• An Overview of the Performance and Scientific Results from the Chandra X-Ray Observatory (CXO)
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• Nonthermal Electrons in Radiatively Inefficient Accretion Flow Models of Sagittarius A*
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• SINFONI in the Galactic Center: young stars and IR flares in the central light month
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• Going with the flow: can the base of jets subsume the role of compact accretion disk coronae?
• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• The Accelerations of Stars Orbiting the Milky Way's Central Black Hole
• Enhanced Angular Momentum Transport in Accretion Disks
• Analysis of isoplanatic high resolution stellar fields by Starfinder code
• Stellar Dynamics in the Galactic centre: Proper Motions and Anisotropy
• Stellar dynamics in the central arcsecond of our galaxy
• A Geometric Determination of the Distance to the Galactic Center
• An Unambiguous Detection of Faraday Rotation in Sagittarius A*
• Variable Infrared Emission from the Supermassive Black Hole at the Center of the Milky Way
• A Jet-ADAF model for Sgr A*
• Imaging Optically-Thin Hot Spots Near the Black Hole Horizon of Sgr A* at Radio and Near-Infrared Wavelengths
• The Nature of the 10 Kilosecond X-ray Flare in Sgr A*
• The Proper Motion of SgrA*: I. First VLBA Results
• XMM-Newton observation of the brightest X-ray flare detected so far from SgrA*
• Polarimetry of near-infrared flares from Sagittarius A*
• Magnetically Driven Accretion Flows in the Kerr Metric II: Structure of the Magnetic Field
• Stellar Orbits Near Sagittarius A*
• On The Nature of the Variable Infrared Emission from Sgr A*
• First Simultaneous NIR/X-ray Detection of a Flare from SgrA*
• Flaring Activity of Sgr A* at 43 and 22 GHz: Evidence for Expanding Hot Plasma
• A Multi-Wavelength Study of Sgr A*: The Role of Near-IR Flares in Production of X-ray, Soft $\gamma$-ray and Sub-millimeter Emission
• X-ray flares reveal mass and angular momentum of the Galactic Center black hole
• Frequency-Dependent Shift in the Image Centroid of the Black Hole at the Galactic Center as a Test of General Relativity
• The Flare Activity of SgrA*; New Coordinated mm to X-Ray Observations
• Variability of Sagittarius A* - Flares at 1 Millimeter
• A polarised infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots
• A New X-Ray Flare from the Galactic Nucleus Detected with the XMM-Newton Photon Imaging Cameras
• The Spectrum and Variability of Circular Polarization in Sagittarius A* from 1.4 to 15 GHz
• Measuring mass and angular momentum of black holes with high-frequency quasi-periodic oscillations
• Near-infrared polarimetry setting constraints on the orbiting spot model for Sgr A* flares
• Light Curves from an MHD Simulation of a Black Hole Accretion Disk
• Intra-day Variability of Sagittarius A* at 3 Millimeters
• A Possible Rossby Wave Instability Origin for the Flares in Sagittarius A*
• II. Accurate Positions and Proper Motions of Stellar SiO Masers near the Galactic Center
• K-band polarimetry of an Sgr A* flare with a clear sub-flare structure
• The Variability of Sagittarius A* at Centimeter Wavelengths
• VLBI Polarimetry of 177 Sources from the Caltech-Jodrell Bank Flat-spectrum Survey
• On the orientation of the Sagittarius A* system
• Spectral Models of Convection-Dominated Accretion Flows
• Periodic Modulations in an X-ray Flare from Sagittarius A*
• Global accretion disk simulations of magneto-rotational instability
• A Testable the Stochastic Acceleration Model for Flares in Sagittarius A*
• A Radio Outburst Nearly Coincident with the Large X-ray Flare from Sgr A* on 2002-10-03
• Magneto-rotational overstability in accretion disks
• Characterising anomalous transport in accretion disks from X-ray observations

Cited by in corpus (60)

• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• Detection of orbital motions near the last stable circular orbit of the massive black hole SgrA*
• An X-ray, IR, and Submillimeter Flare of Sagittarius A*
• A near-IR variability study of the Galactic black hole: a red noise source with no detected periodicity
• X-ray hiccups from SgrA* observed by XMM-Newton. The second brightest flare and three moderate flares caught in half a day
• The two states of Sgr A* in the near-infrared: bright episodic flares on top of low-level continuous variability
• Towards the event horizon -- the supermassive black hole in the Galactic Center
• Millimeter Flares and VLBI Visibilities from Relativistic Simulations of Magnetized Accretion onto the Galactic Center Black Hole
• Sgr A* near-infrared flares from reconnection events in a magnetically arrested disc
• Variability Timescale and Spectral Index of Sgr A* in the Near Infrared: Approximate Bayesian Computation Analysis of the Variability of the Closest Supermassive Black Hole
• Source-intrinsic near-infrared properties of Sgr A*: Total intensity measurements
• Tidal effects on small bodies by massive black holes
• Polarimetry and Astrometry of NIR Flares as Event Horizon Scale, Dynamical Probes for the Mass of Sgr A*
• Prospects for testing the nature of Sgr A*'s NIR flares on the basis of current VLT- and future VLTI-observations
• The mean infrared emission of SagittariusA*
• Simultaneous NIR/sub-mm observation of flare emission from SgrA*
• A parameter survey of Sgr A* radiative models from GRMHD simulations with self-consistent electron heating
• Rapid Variability of Sgr A* across the Electromagnetic Spectrum
• Dynamically important magnetic fields near the event horizon of Sgr A*
• Near infrared flares of Sagittarius A*: Importance of near infrared polarimetry
• Concurrent X-ray, near-infrared, sub-millimeter, and GeV gamma-ray observations of Sgr A*
• A 600 minute near-infrared lightcurve of Sagittarius A*
• The X-ray flaring properties of Sgr A* during six years of monitoring with Swift
• Chandra Spectral and Timing Analysis of Sgr A*'s Brightest X-ray Flares
• Multiwavelength VLBI observations of Sagittarius A*
• Modeling mm- to X-ray flare emission from SgrA*
• The instrumental polarization of the Nasmyth focus polarimetric differential imager NAOS/CONICA (NACO) at the VLT - Implications for time-resolved polarimetric measurements of Sgr A*
• Polarized light from Sgr A* in the near-infrared $K_s$-band
• Simultaneous X-ray and Infrared Observations of Sagittarius A*'s Variability
• A power-law break in the near-infrared power spectrum of the Galactic center black hole
• The extreme luminosity states of Sagittarius A*
• Spacetime Tomography Using The Event Horizon Telescope
• Spitzer/IRAC Observations of the Variability of Sgr A* and the Object G2 at 4.5 microns
• Bright X-ray flares from Sgr A*
• A Systematic Chandra study of Sgr A${}^{\star }$: I. X-ray flare detection
• Coordinated NIR/mm observations of flare emission from Sagittarius A*
• A magnetohydrodynamic model for multi-wavelength flares from Sagittarius~A${}^{\star }$ (I): model and the near-infrared and X-ray flares
• Polarized Emission of Sagittarius A*
• Wisps in the Galactic center: NIR triggered observations of the radio source Sgr A* at 43 GHz
• A "coronal-mass-ejection'' model for flares in Sagittarius A*
• Near-infrared polarimetry as a tool for testing properties of accreting super-massive black holes
• The variability of Sagittarius A* at 3 millimeter
• Magnetic layers and neutral points near rotating black hole
• Multi-Epoch VERA Observations of Sagittarius A*: I. Images and Structural Variability
• Multi-wavelength Variability of Sagittarius A* in July 2019
• Near-infrared Polarimetry of flares from Sgr A* with Subaru/CIAO
• The Relationship Between Simulated Sub-Millimeter and Near-Infrared Images of Sagittarius A* from a Magnetically Arrested Black Hole Accretion Flow
• Soft gamma-ray constraints on a bright flare from the Galactic Center supermassive black hole
• An evolving hot spot orbiting around Sgr A*
• Coordinated multi-wavelength observations of Sgr A*
• Modulated X-ray Emissivity near the Stress Edge in Sgr A*
• Recent Results and Perspectives for Precision Astrometry and Photometry with Adaptive Optics
• Synchrotron Polarization of Relativistic Thermal Electrons
• Flare emission from Sagittarius A*
• Possible evidence from the flaring activity of Sgr A* for a star at a distance of ~3.3 Schwarzscild radii from the blackhole
• Coordinated mm/sub-mm observations of Sagittarius A* in May 2007
• The orbit and nature of the semi-detached stellar companion of Sgr A* super-massive blackhole
• The Galactic Center Black Hole Laboratory
• High-frequency VLBI observations of SgrA* during a multi-frequency campaign in May 2007
• High Energy Emission from the Galactic Center