Observing Orbital Motion in Strongly Curved Spacetime

Observing Orbital Motion in Strongly Curved Spacetime

Institute of Physics, Silesian University in OpavaGabriel Török

CZ.1.07/2.3.00/20.0071 Synergy , GAČR 209/12/P740, 202/09/0772, SGS-01-2013, www.physics.cz

Observing Orbital Motion in Strongly Curved Spacetime :



Timing signatures of accretion disc inhomogeneities



COLLABORATION:

Pavel Bakala, Didier Barret, Vladimír Karas, Michal Dovčiak, Martin Wildner, Dalibor Wzientek, Marek Abramowicz, Luigi Stella, Eva Šrámková, Kateřina Goluchová, Frederic Vincent, Grzegorz Mazur, Tomáš Pecháček

Global EmpiricalModel of Variabilityand Spectra (GRS 1915+105, SPL State)

Response Matrices(Detector)

“DATA” Time and Spectral Distributionof Detected Counts

TIMINGANALYSIS

RESULTS

TOTA

L SO

URC

E FL

UX

MO

DEL

+

Comparing different orbital QPO models, RXTE and LOFT

QPO MODEL

I. Small spots moving along slightly eccentric orbits close ISCO

I. Small spots moving along slightly eccentric orbits close ISCO

Left: RXTE Right: LOFT

POW

ER

POW

ER

II. Toy models of double peak QPOs assuming preferred orbits

II. Toy models of double peak QPOs assuming preferred orbits

Left: RXTE Right: LOFT

POW

ER

III. Elongated spots with LOFT

[LO

FT Y

ELLO

W B

OO

K]

CONCLUSIONS

Ad SMALL SPOTS:The LOFT observations could easily reveal the Keplerian frequency together with its first and second harmonics when the strongest (but still very weak) single signal is around the limits of the RXTE detectability.

Ad ELONGATED SPOTS:The LOFT mission could open a window to observe the epicyclic motion.

Ad SPOT vs. TORUS COMPARISON:We conclude that the ability to recognize the harmonic content of the signal and follow the QPO evolution can help to distinguish between the different proposed physical models.

Observing Orbital Motion in Strongly Curved Spacetime

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