Swift observations of black hole candidate

XTE J1752-223

with P. Casella. T.J. Maccarone & P.A.

Evans

Peter A. Curran

Laboratoire AIM, Irfu /Service d'AstrophysiqueCEA Saclay, France

Swift and X-ray transients

Gamma-ray burst (GRB) satellite:

Burst Alert Telescope(BAT: 15-150 keV)

X-ray Telescope(XRT: 0.2-10 keV)

Ultraviolet & Optical Telescope

(UVOT: UV,U,B,V)

Swift and X-ray transients

Flexible scheduling

Fast pointing

Timing & spectral capabilities

Quasi-simultaneous observations (0.002-150 keV)

Companion Star:cool thermal(nIR-optical-UV)

Accretion Disk:warm/hot thermal(optical-X-ray)

Corona, Jet: non-thermal(radio, X-ray)

All emissions regions probed by Swift

XTE J1752-223

Discovered by RXTE on 2009-10-23

Black-hole candidate with radio-observed jet

Observed by RXTE, Swift, Fermi, Suzaku, MAXI, & ground-based optical/radio telescopes

~50 Swift observations over 8 months (Curran et al. 2010)

X-ray light curves

MAXI4-10 keV

Swift-XRT0.3-10 keV

Swift-BAT15-150 keV

Identifying the states

Identifying the states: XRT-BAT spectra

Hard (power-law)

Soft/thermal

XRTXRT BATBAT

Spectral parameters & states

ha

rd soft

hard

inte

rmed

iate

X-ray light curves & states

qu

iesc

en

ceh

ard

soft

hard

inte

rmed

iate

MAXI light curves1.5-4 keV

4-10 keV

10-20 keV

Matsuoka et al., 2009

Hardness Intensity Diagrams

Hardness Intensity Diagrams

XRT

BAT/MAXI

Hardness Intensity Diagrams

XRT

BAT/MAXI

Fender et al., 2004

XRT power spectra

XRT power spectra

Hard state (average)RMS ~54%

Soft state (average)RMS <12%

XRT power spectra: RMS

ha

rd soft

hardin

term

edia

te

XRT power spectra: QPO?

QPO?Hard state (average)RMS ~54%

Soft state (average)RMS <12%

XRT power spectra: QPO?

QPO?

Hard state (individual sequence)

Optical counterpart

Counterpart (nIR)

IMACS i’ band image

Torres et al., 2009

Counterpart & sub-arcsec position

UVOT v band image

DSS image

Optical light curve variability

Optical – X-ray correlation

Early, hard state

Soft state & later

Optical – X-ray correlation

Early, hard state

Soft state & later

Hysteresis: excess emission

due to hard state jet?

Hysteresis: excess emission

due to hard state jet?

Counterpart colour?

UVOT u-b-v

Colour: 0 < β < 4

Counterpart colour?

XTE J1752-223: Further work

Multi-wavelength spectral fits

Radio – nIR/optical/UV – XRT – RXTE – Fermi

Multi-wavelength spectral fits

Radio – nIR/optical/UV – XRT – RXTE – Fermi

Conclusions

Swift observations of the first known outburst of XTE J1752-223 allowed us to:

Confirm and refine the epochs of the canonical X-ray states

Confirm the optical counterpart and produce a sub-arcsecond position

Discover an optical - X-ray correlation and hysteresis effect

Furthermore, these discussed properties of XTE J1752-223 support its candidacy as a black hole in the Galactic centre region