X-ray Spectroscopy of Bright ULXs

1. X-ray Spectroscopy of Bright ULXs Jon M. Miller (CfA) A. C. Fabian (IoA), M. C. Miller (UMd), G. Fabbiano (CfA)

2. jmmiller@cfa.harvard.edu

3. Disk Models jmmiller@cfa.harvard.edu

4. Focused Emission Models jmmiller@cfa.harvard.edu

5. Isotropic Emission Models Photospheric Emission Disk Emission jmmiller@cfa.harvard.edu

6. XMM-Newton: NGC 1313 X-1 • Disk component: > 8σ • L_X ~ 0.6-2.0 E+40 erg/s • hard:soft  3:1 • kT = 230 +/- 20 eV • Γ = 1.76 +/- 0.07 • Mass Scaling: • T ~ M^(-1/4) • kT ~ 1.0 keV for 10 Msun BHs •  M ~ 4000 Msun • M = ηf2 [K/cos(i)]0.5(d/10kpc)/(8.85km) •  M ~ 400 Msun • L_X / L_Edd •  110 Msun • ~1000 Msun BH @ L_X ~ 0.1*L_Edd ? jmmiller@cfa.harvard.edu

7. XMM-Newton: M81 X-9 • Disk component: 6σ • L_X ~ 1.0-1.4 E+40 erg/s • hard:soft  4:1 • kT = 260 +/- 30 eV • Γ = 1.73 +/- 0.08 • Mass Scaling: • T ~ M^(-1/4) • kT ~ 1.0 keV for 10 Msun BHs •  M ~ 2000 Msun • M = ηf2 [K/cos(i)]0.5(d/10kpc)/(8.85km) •  M ~ 330 Msun • L_X / L_Edd •  200 Msun • ~1000 Msun BH @ L_X ~ 0.1*L_Edd ? jmmiller@cfa.harvard.edu

8. NGC 1313 X-1: Radio and Optical DSS • X-1: radio/X-ray ~ 5*10-6 • (Colbert 1995) • beaming creates flat νFν spectra • cannot beam blackbody spectra • consistent w/ Galactic XRBs • (Fender & Kuulkers 2001) • X-1 and X-2 illuminate symmetric • X-ray photoionization nebulae (Pakull & Mirioni 2002) • No young clusters within 380 pc of X-1, few kpc of X-2 (Larsen 1999) jmmiller@cfa.harvard.edu

9. Pakull & Mirioni 2001 • M81X-9: • Radio and Optical Data • X-9: radio/X-ray ~ 2*10-6 • beaming creates flat νFν spectra • cannot beam blackbody spectra • consistent w/ Galactic XRBs • (Fender & Kuulkers 2001) • X-9 may illuminate nebula • (Pakull & Mirioni 2002) DSS jmmiller@cfa.harvard.edu

10. Photospheres and Hard Components • (1) L_mech ~ L_rad*(v/c) • (2) R_phot ~ R_Schw.*(c/v)^2 • (see King 2003, also Titarchuk et al. 2003) • soft from photsph: L_rad ~ L_phot~ L_soft • hard X-rays via shocks: L_hard ~ L_mech • if hard X-rays strong: L_hard ~ L_soft [L_rad] • (1) only holds if (v/c) ~ 1,  R_phot ~ R_Schw jmmiller@cfa.harvard.edu

11. XTE J1550-564 at L_X > 10^39 erg/s Sobczak et al. 2000 jmmiller@cfa.harvard.edu

12. QPOs: Hard and Central Homan et al. 2001 XTE J1550-564 jmmiller@cfa.harvard.edu

13. Fe K Lines: Central, Tied to Hard X-rays Gilfanov 2000 Miller et al. 2002 XMM, RXTE: XTE J1650-500 Chandra: GX339-4 Miller et al. 2003 Zdziarski 1999 jmmiller@cfa.harvard.edu

14. The M82 ULX • Very high luminosity: • L_X > 5 E+40 erg/s • mHz QPOs are observed • (XMM & RXTE) • Broad Fe K emission line • The inner regions of the disk are likely seen clearly. • (Strohmayer & Mushotzky 2003) jmmiller@cfa.harvard.edu

15. M81 X-9 jmmiller@cfa.harvard.edu

16. 100 ksec on NGC 1313 X-1 with Con-X jmmiller@cfa.harvard.edu

17. Summary & Conclusions • Many, if not most ULXs are probably 10 Msun BHs. • Some are likely 100-1000 Msun BHs. • In some of the brightest sources, cool thermal emission is required. • This is most plausibly tied to disks; when combined with multi-wavelength data the picture is strongly suggestive of IMBHs. • “Put the squeeze” on ULXs using techniques learned in study of Galactic BHs and AGN: Fe K lines, QPOs, power spectra, states. • Future sensitive observations of bright ULX sources with Chandra and XMM-Newton can reveal improved evidence for IMBHs, distinct types. • Radio, optical work is very promising. jmmiller@cfa.harvard.edu