1. Constraints on the mass and radius of neutron star in Aql X-1 Zhaosheng Li ( 李兆升 ) Department of Astronomy Peking University

2. Equation of States Gravity bound Hadron star Hybrid star Hyperon Core (R > 13 km) Fortin et al.(2014) PSR J1614-2230 PSR J0348+0432 Self-bound Quark star Quark-cluster star

3. How to constrain the M-R of NS? Thermal emission in qLMXBs X-ray bursts Aql X-1

4. LMXB “Switched on”: Accretion induced outburst “Switched off”: Quiescence transient source

5. qLMXBs in Globular Clusters Guillot et al. (2013) Deep Crustal Heating Brown et al. (1998) nsatmos

6. qLMXBs in Globular Clusters Guillot et al. (2013) Lattimar & Steiner (2013) nsatmos

7. qLMXBs in Globular Clusters Guillot et al. (2013) nsatmos H/He atmosphere Lattimar & Steiner (2013)

8. Type I X-ray burst in LMXB

9. Hydrogen or Helium Galloway et al. (2008)

10. Burst Spectra A burst from 4U 1728-34 Hot atmosphere emission Blackbody spectra

11. PRE X-ray Burst Photospheric Radius Expansion Burst 4U 1728-34 Güver et al. 2012a Expansion->Contraction->Cooling Cooling on the whole surface L~L Edd at touchdown moment

12. Color Correction Factor Güver et al. 2012a

13. Summary Thermal emission in qLMXBs Atmosphere composition Very long time monitoring (10^32-33 erg/s) PRE bursts Color correction factor (f c ) Atmosphere composition (X)

14. Aql X-1 Companion Spectral type K7 main sequence star 4-6.5 kpc (Chevalier et al. (1999)) PRE bursts RXTE, Galloway (2008) Quiescent Chandra, XMM-Newton, Swift (Rutledge et al. (2001), Zelati et al. (2011, 2014))

15. Aql X-1 variability F. Coti Zelati et al. 2014 Two flares during quiescence

16. Consequence of accretion Heating the atmosphere Enhanced the PL component No evidence of affect M-R F. Coti Zelati et al. 2011, 2014

17. Quiescent spectra Chandra+Newton quiescent Obs. tbabs(nsatmos+powerlaw) Hydrogen atmosphere

18. PRE bursts 50049-02-13-01

19. The M-R of Aql X-1 D=4.5 kpc

20. D=5.5 kpc

21. D=6.5 kpc Z.S. Li 2015, in prep.

22. Conclusions Aql X-1 Quiescent observation (Chandra, XMM-Newton, Swift) PRE X-ray burst Tighter constraints on M-R Future Works (XTP, NICER…) PRE bursts, Quiescence Spectra, Pulse Profile…