Chandra observations of sgr a
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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*

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Chandra observations of sgr a

Chandra Observations of Sgr A*

Frederick Baganoff

Massachusetts Institute of Technology


Chandra observations of sgr a

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

Chandra Galactic Center Deep Field

8.4 x 8.4 arcminutes


Chandra 3 color image of the central parsec

Chandra 3-Color Image of the Central Parsec


Vla 6 cm image of sgr a west minispiral

VLA 6 cm Image of Sgr A West Minispiral


Radio image of sgr a west and circumnuclear disk

Radio Image of Sgr A West and Circumnuclear Disk

Red: HCN

Blue: 6 cm


X ray image and 6 cm contours of sgr a west

X-ray Image and 6 cm Contours of Sgr A West


Chandra observations of sgr a

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

  • 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)


Chandra observations of sgr a

2002 May 22-23 – Orbit 1, Part 1


Chandra observations of sgr a

2002 May 24 – Orbit 1, Part 2

May 24 19:42 UT

5x, 1.7 hr


Chandra observations of sgr a

2002 May 25-27 – Orbit 2

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


Chandra observations of sgr a

2002 May 28-30 – Orbit 3

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


Chandra observations of sgr a

2002 June 3-4 – Orbit 5


Sgr a multiwavlength monitoring campaign

Sgr A* Multiwavlength Monitoring Campaign


Three large x ray flares from sgr a

Three Large X-ray Flares from Sgr A*


Chandra observations of sgr a

Very Long Baseline Array – 7 mm

  • 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

NH = 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

  • 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)

  • 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


Chandra observations of sgr a

Integrated X-ray Spectrum of Sgr A*

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


Radial profile of central 10 arcseconds

Radial Profile of Central 10 Arcseconds

Slope = 1.0


Chandra lightcurve of sgr a

Chandra Lightcurve of Sgr A*

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*

19-20 June 2003

2.2um

Eckart, Schoedel, et al.


Vlt ao images

VLT AO Images

Sgr A* bright

Sgr A* bright

Sgr A* dim


Bayesian blocks representation of x ray lightcurve

Bayesian Blocks Representation 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

  • 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*


Sgr a and x ray transients in the central arcminute of the galaxy

Sgr A* and X-ray Transients in the Central Arcminute of the Galaxy

1 hour / frame

6 days 17 hours


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