1 / 18

Kazutaka Yamaoka (Aoyama Gakuin University), On behalf of the MAXI and Suzaku team

Suzaku observations of two Galactic black hole candidates XTE J1752-223 and MAXI J1659-152 triggered by MAXI. Kazutaka Yamaoka (Aoyama Gakuin University), On behalf of the MAXI and Suzaku team. Outline. Coordinated MAXI and Suzaku observations Suzaku observations of XTE J1752-223

kaz
Download Presentation

Kazutaka Yamaoka (Aoyama Gakuin University), On behalf of the MAXI and Suzaku team

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Suzaku observations of two Galactic black hole candidates XTE J1752-223 and MAXI J1659-152 triggered by MAXI Kazutaka Yamaoka (Aoyama Gakuin University), On behalf of the MAXI and Suzaku team

  2. Outline • Coordinated MAXI and Suzaku observations • Suzaku observations of XTE J1752-223 with MAXI results Please also see Nakahira et al. P-1 (MAXI) and Koyama et al. P-2 (Suzaku) • Very preliminary results from Suzaku observations of MAXI J1659-152 • Summary

  3. Coordinated MAXI and Suzaku observations • High sensitive all-sky X-ray survery with MAXI15mCrab@day + Wide-band and high-sensitive X-ray observations with Suzaku Very powerful collaboration for studying X-ray transients. e.x. Discovery of a new MAXI source  Identify the nature of the source with Suzaku • Suzaku ToO Observations by MAXI team have been approved since AO5. • 4 Suzaku ToO observations triggered by MAXI team so far

  4. BHC XTE J1752-223 • Discovered by the RXTE/PCA Galactic-Center scan observations (Markwardt et al. 2009) • MAXI confirms this new transient and monitor the entire outburst. (Nakahira et al. 2010PASJ, Nakahira et al. P-1 ) • Identified as a black hole candidateby RXTE. • Displayed Hard –to-soft, and Soft-to-hard transitions. Bipolar plasma ejection events, i.e. jets, were detected. • The distance, the black hole mass, and the inclination angle are still unknown. XTEJ1752-223

  5. Suzaku observation of XTE J1752-223 Suzaku observation Details of observations • ObservationDate2010-02-24 04:58:00 – 2010-02-25 04:27:24 (UT) • Total exposure 41 ksec • ＸＩＳ Exposure0.5 ksec (XIS 1), 6.1 ksec (XIS 0,3) • Observation directionHXD nominal • ＸＩＳ mode • Full window 0.1s burst option (XIS 1) 1/4 window 0.3s burst option (XIS 0.3) Suzaku observed “High/Soft state” Low/hard High/Soft

  6. The Suzaku/XIS light curve During the obs., the XIS intensity and spectral shape do not change significantly. Produce the XIS spectra by averaging over the whole observation. XIS count rate : 0.5-10 keV Hardness ratio:2-10 keV/0.5-2 keV About 1 day

  7. Suzaku wide-band spectra XIS1 Detected up to ~ 50 keV with HXD/PIN. The HXD/GSO could detect no significant signals above 50 keV. HXD/PIN XIS0+3 HXD/GSO Detection llimit Energy(keV)

  8. Spectral modeling of wide-band spectra Modeling with the Multi-Color Disk model (Mitsuda et al. 1984) plus a power-law (χ2 /dof = 508/339) XIS1 XIS0+3 Power law Γ=2.34+/-0.07 MCDmodel Tin=0.53+/-0.01 keV Rin(cos i)1/2 /(D/10 kpc) = 117.9+/-2.0 km HXD/PIN νFνspectra Power law MCD

  9. Results from RXTE and MAXI observations RXTE and MAXI monitoring observations show that the innermost radii are almost constant at 110~130 km, which is independent of X-ray flux. This value is almost consistent with Suzaku measured one.  Can estimate the black hole mass Innermost temp. Tin (keV) Innermost radius Rin Photon index Γ Flux 3-50 keV

  10. Estimation of the black hole mass Suzaku measured innermost radius: Rin(cosi)1/2 /(D/10 kpc) =117.9±2.0 (km) • rin=ξκ2Rin(Kubota et al. 1998) κ=1.7：Spectral hardening factor (Shimura & Takahara 1995) ξ=0.412: boundary condition near the inner edge of the disk = 198.5±3.4 x(D/10 kpc) x (cosi /cos 60°)-1/2 （km) If we assume a Schwartzchild black hole, the innermost stable circular orbit (ISCO): 3Rs=6GM/c2=8.86 (M/M◎) km  BHmass : M= 22.4±0.4 x (D/10 kpc) x (cosi /cos 60°)-1/2(M◎) Precise determination of a distance and an inclination angle will be desired in a future.

  11. BHC MAXI J1659-152 • The Swift/BAT discovered a new source as GRB 100925A on Sep. 25, 2010 (Mangano et al. GCN #11296). • The MAXI/GSC independently found a new X-ray source as MAXI J1659-152 (Negoro et al. Atel #2873). • RXTE follow-up observations reveal it as a black hole candidate. (Kalamkar et al. Atel # 2881) • Many multi-wavelength observations were performed due to the Swift/BAT GRB trigger and its source location well above the Galactic plane. Sep. 24 Sep. 25 MAXI J1659-152

  12. Suzaku observations of MAXI J1659-152 • Details of the three observations • Observation Dates • Sep. 29, 30, Oct. 1-2, 2010 • XIS0/HXD exposure • 1.6 k / 16.3 ksec • 15.0 k / 23.5 ksec • 4.9 k / 30.7 ksec • Observation directionHXD nominal • ＸＩＳ mode • ¼ window with no burst option (Sep. 29, 30) • 0.3s burst option (Oct 1-2) • Suzaku observed a rare “intermediate state”in the rising phase. High/Soft MAXI/GSC Hardness-Intensity diagram Low/hard

  13. Preliminary results of Suzaku data The XIS+PIN spectra are explained by the disk blackbody plus power law with an exponential cutoff. QPO features at about 3 Hz are detected in the HXD/PIN data for all the three observations. Cut-off LF QPO The intermediate observations with Suzaku might reveal a disk-corona-jet geometry around the BH during the state transition.

  14. Summary • MAXI and Suzaku coordinated observations since AO5 • Four sources so far: V0332+53、XTEJ1752-223、GX304-1, and MAXI J1659-152 • Suzaku observation of XTE J1752-223 • High/Soft state • The 1-50 keVspectra are explained by MCD model plus power law. • Suzaku and RXTE observation suggests a constancy of innermost radius at 120~130 km  Estimation of the black hole mass 22.4+/-0.4 M◎for i=60°, D=10 kpc • Further examination of the “ disk-line feature” • Suzaku observation of MAXI J1659-152 • Intermediate state in the rising phase. • 0.6-70 keV spectra are explained by MCD model plus cutoff power law. • The QPO features are present in the HXD/PIN power spectrum.

  15. Presence of a disk line？ Reis et al. (2010) suggested a presence of a disk line using the same Suzaku data. They fitted the continuum using the1.3-4.5, 8.0-10.0, 20-45 keVdata. We can reproduce the same feature with the same procedures, but using all the energy bands, we can see a reflection feature instead. Suzaku RXTE/PCA

  16. Pile-up effects PHA Ratio to the spectra in the Outer regions(90``<r<120``) • For bright sources, the XIS spectra were affected by pile-up effects。 • In the central region, the spectra get harder. • Need to exclude • at least the • region with • r<60`` r<30’’ 30’’<r<60’’ 60’’<r<90’’

  17. MAXI light curve of V0332+53 Suzaku observation

  18. XIS spectra of V0332+53 The spectrum is rather hard photon index ~1 NH= 1.55 (-0.17,+021)x1022 cm-2 α= 1.07(-0.09, +0.10) Flux 2-10 keV 6.4x10-12 erg/cm2/s  ~0.3 mCrab (Crab:2.2x10-8) χ2/dof = 320/325

More Related