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Chandra Observations of Sgr A*. Frederick Baganoff. Massachusetts Institute of Technology. Chandra Galactic Center Deep Field. 17 x 17 arcmin 40 x 40 pc 590 ks. Red 2-3.7 keV Green 3.7-4.5 keV Blue 4.5-8 keV. Chandra Galactic Center Deep Field. 8.4 x 8.4 arcminutes.

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Chandra observations of sgr a

Chandra Observations of Sgr A*

Frederick Baganoff

Massachusetts Institute of Technology


Chandra Galactic Center Deep Field

17 x 17 arcmin

40 x 40 pc

590 ks

Red 2-3.7 keV

Green 3.7-4.5 keV

Blue 4.5-8 keV







2000 October 26-27

(Baganoff et al. 2001)

Oct 27 05:42 UT

45x, 4 hr


Multiwavelength monitoring of the supermassive black hole in the galactic center

Multiwavelength Monitoring of the Supermassive Black Hole in the Galactic Center

F.K. Baganoff1

M.W. Bautz1, G.R. Ricker1, W.N. Brandt2, G. Chartas2,

E.D. Feigelson2, G.P. Garmire2,M. Morris3, E.E. Becklin3,

A.M. Ghez3, S.D. Hornstein3, A.M. Tanner3, A.S. Cotera4, P.M. Hinz4,

W.F. Hoffmann4, M.R. Meyer4, A. Eckart5, R. Genzel6, J.-H. Zhao7,

R.M. Herrnstein7, J.L. Hora7, J.-P. Macquart8, Y. Maeda9, R.J. Sault10,

G.B. Taylor11, F. Walter11

1MIT, 2UCLA, 3Penn State, 4Steward Obs., 5U. Cologne, 6MPE, 7CfA,

8U. Groningen, 9ISAS, 10ATNF, 11NRAO


Observatories participating in sgr a monitoring campaign
Observatories Participating in Sgr A* Monitoring Campaign in the

  • Chandra (12-62 nm)

  • Keck (2 & 10 mm)

  • Very Large Telescope (3-5 mm)

  • Magellan (10 mm)

  • Submillimeter Array (1.3 mm)

  • Caltech OVRO Millimeter Array (3 mm)

  • Australia Telescope Compact Array (3 mm)

  • Very Large Baseline Array (7 mm)

  • Very Large Array (7mm, 1.3 cm, 2 cm)



2002 May 24 – Orbit 1, Part 2 in the

May 24 19:42 UT

5x, 1.7 hr


2002 May 25-27 – Orbit 2 in the

May 26 04:24 UT

6x, 0.75 hr

May 24 19:42 UT

5x, 1 hr

May 26 13:47 UT

5x, 0.5 hr


2002 May 28-30 – Orbit 3 in the

May 28 15:36 UT

25x, 1 hr

May 29 18:33 UT

13x, 0.5 hr

May 29 06:03 UT

12x, 1.5 hr





Very Long Baseline Array – 7 mm in the

  • No significant flux variability detected (upper limit about 30%)

  • No extended structure appeared within 5 hour track (upper limit about 10 mJy)


Model absorbed dust scattered power law

N in the H = 6.0 x 1022 cm-2

G = 1.3 (0.9-1.8)

FX = 1.6 x 10-12 erg cm-2 s-1

LX = 2.0 x 1034 erg s-1

D = 8 kpc

Model: Absorbed, Dust-Scattered Power Law

Integrated X-ray Spectrum of

Sgr A* Flares


Summary sgr a flares
Summary - Sgr A* Flares in the

  • Chandra observed Sgr A* for 139 hr over a two-week period in late May to early June 2002

    • 3 X-ray flares with amplitudes >10x detected in a 28-hr period

    • 4 X-ray flares with amplitudes ~5x detected in addition

    • Typical flare duration is about 1 hr (0.5-4 hr)

  • XMM-Newton has detected 2 large X-ray flares (Goldwurm et al. 2002; Porquet et al. 2003)

    • Amplitudes, durations, and rise/fall timescales similar to Chandra flares

    • First flare had hard spectrum G ~ 1.1

    • Second flare - brightest to date (90x) - has soft spectrum G ~ 2.5

    • Distribution of flare properties? Different physical conditions?


Summary sgr a flares continued
Summary - Sgr A* Flares (continued) in the

  • Strong X-ray flares occur about once per day

  • Observed frequent, large-amplitude, short-duration flaring behavior of Sgr A* is unique among SMBHs

  • Probably selection effect: flares too faint to detect in other galaxies

  • Behavior inconsistent with X-ray binaries and not seen from any of the other >2,300 X-ray point sources in the field


Integrated X-ray Spectrum of Sgr A* in the

Quiescent Emission

Model: Absorbed, Dust-Scattered, NIE Plasma

NH = 5.9 x 1022 cm-2

G = 4-5 keV

EFe = 6.59 (6.54-6.64) keV

Line is narrow and NIE

FX = 1.8 x 10-13 erg cm-2 s-1

LX = 1.4 x 1033 erg s-1

D = 8 kpc

<LF> / <LQ> = 14.0



Chandra lightcurve of sgr a
Chandra Lightcurve of Sgr A* in the

Eckart, Baganoff et al. (2004)

2-8 keV

19-20 June 2003

Counts per second

Minutes


Vlt lightcurve of sgr a
VLT Lightcurve of Sgr A* in the

19-20 June 2003

2.2um

Eckart, Schoedel, et al.


Vlt ao images
VLT AO Images in the

Sgr A* bright

Sgr A* bright

Sgr A* dim


Bayesian blocks representation of x ray lightcurve
Bayesian Blocks Representation in the of X-ray Lightcurve

  • Excess amplitude ~x2

  • Duration ~40-60 min

  • 99.923% confidence

Scargle (1998)


X ray and nir lightcurves
X-ray and NIR Lightcurves in the

  • First simultaneous detection of X-ray and NIR flare

  • At least in this case, X-ray and NIR photons appear to come from a single electron population

  • Lx ~ 6x1033 erg/s

  • Lnir ~ 5x1034 erg/s

  • Spectral index ~ 1.3

  • X-rays coincident within 180 mas

  • NIR coincident within 14 mas

  • X-ray flares from Sgr A*



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