An 8 hour characteristic time-scale in submillimetre light curves of Sagittarius A*

Abstract

We compile and analyse long term (~10 year) submillimetre (1.3, 0.87, 0.43 mm, submm) wavelength light curves of the Galactic centre black hole, Sagittarius A*. The 0.87 and 0.43 mm data are taken from the literature, while the majority of the 1.3 mm light curve is from previously unpublished SMA and CARMA data. We use Monte Carlo simulations to show that on minute to few hour time-scales the variability is consistent with a red noise process with a 230 GHz power spectrum slope of 2.3+0.8-0.6 at 95% confidence. The light curve is de-correlated (white noise) on very long (month to year) times. In order to identify the transition time between red and white noise, we model the light curves as a stochastic damped random walk process. The models allow a quantitative estimate of this physical characteristic time-scale of 8-4+3 hours at 230 GHz at 95% confidence, with consistent results at 345 and 690 GHz. This corresponds to ~10 orbital times or ~1 inflow (viscous) time at R = 3 Rs, a typical radius producing the 230 GHz emission as measured by very long baseline interferometry and found in theoretical accretion flow and jet models. This time-scale is significantly shorter (longer) than those measured at radio (near-infrared, NIR) wavelengths, and is marginally inconsistent with the same variability mechanism operating in the submm and NIR for the expected t ~ R^3/2 scaling. It is crudely consistent with the analogous time-scale inferred in studies of quasar optical light curves after accounting for the difference in emission radius. We find evidence that the submm variability persists at least down to the ISCO, if not the event horizon. These results can be compared quantitatively with similar analyses at different wavebands to test for connections between the variability mechanisms, and with light curves from theoretical models of accreting black holes.

arXiv comment12 pages, 9 figures, submitted to MNRAS 6/2013

References in corpus (64)

• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• Event-horizon-scale structure in the supermassive black hole candidate at the Galactic Centre
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• Nonthermal Electrons in Radiatively Inefficient Accretion Flow Models of Sagittarius A*
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• Active Galactic Nuclei as scaled-up Galactic black holes
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• GRMHD Simulations of Magnetized Advection Dominated Accretion on a Non-Spinning Black Hole: Role of Outflows
• The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
• Non-linear X-ray variability in X-ray binaries and active galaxies
• The orbit of the star S2 around SgrA* from VLT and Keck data
• Measuring the broadband power spectra of active galactic nuclei with RXTE
• The Quasar Accretion Disk Size - Black Hole Mass Relation
• The Quasar Accretion Disk Size -- Black Hole Mass Relation
• Quantifying Quasar Variability As Part of a General Approach To Classifying Continuously Varying Sources
• A gas cloud on its way towards the super-massive black hole in the Galactic Centre
• Radiative Models of Sgr A* from GRMHD Simulations
• Soft state of Cygnus X-1: stable disk and unstable corona
• 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*
• Interferometric Detection of Linear Polarization from Sagittarius A* at 230 GHz
• A size of ~1 AU for the radio source Sgr A* at the centre of the Milky Way
• The Sizes of the X-ray and Optical Emission Regions of RXJ1131-1231
• Assessing Quantitative Results in Accretion Simulations: From Local to Global
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• An X-ray, IR, and Submillimeter Flare of Sagittarius A*
• 1.3 mm Wavelength VLBI of Sagittarius A*: Detection of Time-Variable Emission on Event Horizon Scales
• Interferometric Measurements of Variable 340 GHz Linear Polarization in Sagittarius A*
• Evidence for X-ray synchrotron emission from simultaneous mid-IR to X-ray observations of a strong Sgr A* flare
• First Simultaneous NIR/X-ray Detection of a Flare from SgrA*
• Evidence for Low Black Hole Spin and Physically Motivated Accretion Models from Millimeter VLBI Observations of Sagittarius A*
• Flaring Activity of Sgr A* at 43 and 22 GHz: Evidence for Expanding Hot Plasma
• The Intrinsic Size of Sagittarius A* from 0.35 cm to 6 cm
• Methods for detecting flaring structures in Sagittarius A* with high frequency VLBI
• On the use of structure functions to study blazar variability: caveats and problems
• A near-IR variability study of the Galactic black hole: a red noise source with no detected periodicity
• A Stochastic Model for the Luminosity Fluctuations of Accreting Black Holes
• Estimating the Parameters of Sgr A*'s Accretion Flow Via Millimeter VLBI
• The two states of Sgr A* in the near-infrared: bright episodic flares on top of low-level continuous variability
• The Flare Activity of SgrA*; New Coordinated mm to X-Ray Observations
• Intrinsic Size OF Sgr A*: 72 Schwarzschild Radii
• Variability of Sagittarius A* - Flares at 1 Millimeter
• Millimeter Flares and VLBI Visibilities from Relativistic Simulations of Magnetized Accretion onto the Galactic Center Black Hole
• Simultaneous Chandra, CSO and VLA Observations of Sgr A*: The Nature of Flaring Activity
• Simultaneous Multi-Wavelength Observations of Sgr A* during 2007 April 1-11
• Source-intrinsic near-infrared properties of Sgr A*: Total intensity measurements
• Time Dependent Models of Flares from Sagittarius A*
• Tilted black hole accretion disc models of Sagittarius A*: time-variable millimetre to near-infrared emission
• Intra-day Variability of Sagittarius A* at 3 Millimeters
• Keck Observations of the Galactic Center Source G2: Gas Cloud or Star?
• New observations of the gas cloud G2 in the Galactic Center
• Simultaneous NIR/sub-mm observation of flare emission from SgrA*
• Galactic Center Research: Manifestations of the Central Black Hole
• A geometric crescent model for black hole images
• Radially Extended, Stratified, Local Models of Isothermal Disks
• Near-Infrared and X-ray Quasi-Periodic Oscillations in Numerical Models of Sgr A*
• A power-law break in the near-infrared power spectrum of the Galactic center black hole
• Understanding the Radio Variability of Sgr A*
• Submillimeter Quasi-Periodic Oscillations in Magnetically Choked Accretion Flows Models of Sgr A*
• Flares and variability from Sagittarius A*: five nights of simultaneous multi-wavelength observations
• Occultation of the Quiescent Emission from Sgr A* by IR Flares
• Constraining the Flaring Region of Sagittarius A* By 1.3mm VLBI Measurements

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• Principal Component Analysis as a Tool for Characterizing Black Hole Images and Variability
• Far Infrared Variability of Sagittarius A*: 25.5 Hours of Monitoring with $Herschel$
• A Black Hole Mass-Variability Time Scale Correlation at Submillimeter Wavelengths
• Flares and their echoes can help distinguish photon rings from black holes with space-Earth very long baseline interferometry
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• Detection of a 20 minute time lag observed from Sgr A* between 8 and 10 GHz with the VLA
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• Photometric Constraints on Intermediate-mass Black Holes in the Galactic Centre
• Radiative energy from a reconnection region around massive black hole
• Remarkable correspondence of Sagittarius A* submillimeter variability with a stellar-wind-fed accretion flow model