Small glitches detected at Nanshan

1. Small glitches detected at Nanshan 周祖荣，王晶波，袁建平，王娜，党世军 中国科学院新疆天文台 2019年6月27日

2. Outline ● Pulsar ,Glitch And Pulsar Timing ● My Project ● Summary

3. Pulsar ●Neutron stars:highly magnetized,rapidly rotating, emission pulses. ● Formation: supernova explosion,white dwarfs collapse. ● Mass: ~ 1.4Msun ● B: 10^8 ~10^15G ● Density:10^14 g / cm^3 ● Period: ~ 1.4ms-10s ● Diameter: ~ 10-15km ● Population: at present, ~2700( ~ 300MSP, most of MSP in binary) ● High precision timing：good probes of interstellar medium,magnetic field, and GW background.

4. Glitch Sudden jumps in rotational frequency(v=Ω/2π) PSR B0833-45,1981.10 (McCulloch et al.1983)

5. Pulsar Timing(Model & Steps) new .par file Fit proper motion Data Process Initial .par file Red noise model

6. Pulsar Timing Proper motion(Lorimer & Kramer, 2005)

7. Pulsar Timing ● The irregular period changes include two categories: glitch and timing noise. Timing noise (G.Hobbs&A.G.Lyne2010） Glitch(C.M.Espinoza&A.G.Lyne2011)

8. My Project My project is to process timing data of 20 pulsars at NanShan. • We have obtained their rotation parameters. • Make a discussion for small glitches .

9. My Project • We have found 57 new glitches of 20 pulsars,7 pulsars were first to glitch. • We made a large sample ananlysis,after adding the glitch parameters of http://www.jb.man.ac.uk/pulsar/glitches/gTable.html .

10. Spin-down rate & Recoveries(Large glitches) PSR J2337+6151(J.P.Yuan et al.2010) PSR J1718-3718(Manchester et al.2011) PSR J0835-4510(N.Wang et al.2000) (by myself)

11. My Project Divided 57 glitches into 3 categories according to the average spin-down rate and frenquency: 1,almost unchanged;2,decrease; 3, increase. 1,almost unchanged

12. My Project Divided 57 glitches into 3 categories according to the average spin-down rate and frenquency: 1,almost unchanged;2,decrease; 3, increase. 2,decrease

13. My Project Divided 57 glitches into 3 categories according to average spin-down rate and frenquency: 1,almost unchanged;2,decrease; 3, increase. 3,increase

14. Summary ● 1. Detected 57 new glitches of 20 pulsars,for PSR J0215+6218,PSR J0525+1115,PSR J0846-3533,PSR J1835-1020,PSR J1836-1008,PSR J1847-0402 and PSR J2219+4754 were first to glitch. ● 2. We obtained 57 glitch parameters for 20 pulsars, and made a large sample ananlysis(57+522=579glitches) after adding the glitch parameters of http://www.jb.man.ac.uk/pulsar/glitches/gTable.html. The distrition of glitches is bimodal, and the number of small glitches is larger than that of great glitches. ● 3. All observed relative glitch sizes range between 8.0E-11and 7.0E-9, all pulsars with characteristic age between 44 kyr and 7.6Myr.The distribution of glitch size and age is very discrete. However, with the increase of age, small glitches are more likely to occur. ● 4. We divided 57 glitches into 3 categories according to average spin-down rate and frenquency: almost unchanged , decrease ,increase.We found that small glitch also have discoveris and decay after-glitch.The kinetics of large and small glitches is very similar. ● 5. The negative value of were rare events in glitches,and it tends to occur in small glitches. However,in the small glitch events of increasing average spin-down rate, the value tends to be more negative.

15. References

16. Thanks ！ Xinjiang Astronomical Observatory,CAS