eXTP Workshop Timing Ultraluminous X-ray Sources with eXTP Hua Feng Tsinghua University

ULXs Non-nuclear accreting compact objects Luminosity higher than the Eddington limit of stellar mass BHs IMBHs 103-104 M⊙ Pop III; star clusters; Sub-Eddington Stellar mass BHs ~10 M⊙ or massive Similar to GBHBs or remnants of low-Z stars; Near or super-Eddington Could also be a pulsar (M82 X-2), but not a general case

X-ray timing – model independent mass estimate Low frequency QPOs: spectral-timing correlation Compare QPO frequency at the same spectral state and spectral parameters GRS 1915+105 15 M⊙ XTE J1550-564 10 M⊙ LFQPO itself is not a good indicator of the BH mass, because it varies in a wide frequency range. But the QPO frequency is correlated with some spectral properties. An empirical method is to using such correlations and compare the QPO frequency at the same spectral state and same spectral parameters. (Titarchuk & Fiorito 2004)

Shaposhnikov &Titarchuk 2009

HFQPOs

Timing ULXs M82 X-1 NGC 5408 X-1 NGC 6946 X-1 M82 X-2 (X42.3+59) XMM-Newton XTE NGC 5408 X-1 NGC 6946 X-1 M82 X-2 (X42.3+59) Chandra Strohmayer et al.; Feng et al; Rao et al.; Pasham et al.

M82 X-1 with eXTP 2-10 keV, 5000 cm2, 50 ks

Sources with QPO detectable 2XMM ULXs catalog， Given 5σ significance, we expect to detect M82 X-1 like LFQPOs in 32 ULXs

Other targets ULXs BHBs in M31 BHBs in LMC XRBs in Quiescence

HFQPOs for M82 X-1 Based on LFQPOs in XTE J1550-564 20 = 184 Hz Q = /FWHM = 2.2 – 8.3 Assuming MBH = 500 M⊙, 20 = 3.72 Hz, FWHM = 0.5 (Q = 7.4) 84 ks exposure, rms = 7%,  = 6.5 Work done in 2012 6 year average result with XTE (Pasham et al. 2014)