Detection radio emission from AXP 4U 0142+61

1. Detection radio emission from AXP 4U 0142+61 Malofeev V.M., Teplykh D.A., Rodin A.E., Logvinenko S.V. Pushchino Radio Astronomy Observatory of Lebedev Physical Institute, Russia Cairo 2009

2. Anomalous pulsars • Geminga • Anomalous X-ray pulsars (AXPs) • Soft gamma-ray repeaters(SGRs) • X-ray dim isolated neutron stars (XDINSs) • Compact X-ray objects in remnant of supernova (CCO) • Transient pulsars (RRATS + switch off)… Cairo 2009

3. Cairo 2009

4. Main problem None of the AXPs and SGRs show the evidence of a binary companion and the main problem is the source of their energies, because their X-ray luminosities are much higherthan can be provided by the rotational kinetic-energy losses. The most popular magnetar model ofThompson & Duncan (1996) proposes the enormous surface magnetic fields 1014- 1015 G and theabsence of radio emission from these objects (Baring & Harding 1998). Many attempts have beenmade to detect radio emission, for example Gaensler et al. (2001). Cairo 2009

5. Observations • LPA: 111.5 ± 1.5 МHz, 3.3 m / cos , Aef  20 000 m2 • Cross Type Radio Telescope: 87 МHz, 62 МHz, 42 MHz 15 m / cos , Aef  5 – 8  103 m2 • Receivers: 64  20 kHz, t = 25.6 ms, 51.1 ms, 61.9 ms • Digitalreceivers at 111 and 42 MHz: 511  5 kHz 4U 0142+61 Recording of 46 periods or 23 double periods Cairo 2009

6. Large Phased Array Cairo 2009

7. Cross Type Radio Telescope Cairo 2009

8. Average pulse profiles of the AXPs: • 4U 0142+61 • 1RXS 1708-4009 • 1E 2259.1+586 An optical counterpart for 4U 0142+61 (R = 24.98) F. Hulleman et al., Nature 408, 689, 2000. Optical pulsations (27%) B.Kern, C.Martin, Nature 417, 527, 2002. Cairo 2009

9. 1E2259+586 111.23 MHz Malofeev et al 2001,2004,2005 Sum of 12 days 312 periods 624 periods S/n = 10 • The observations were started in 1999 • Pulse profile obtained when the observing window equals twice the apparent period (p = 6.978 s). The summing of 12 days was made with the superposition of visible pulses at the phase ~ 0.58 (red arrow). Second pulse shows up at the phase 1.58 (blue arrow). The mean profile for one period obtained by the folding of data (lower). Cairo 2009

10. XTE J1810-197 F.Camilo et al., Nature, 442, 892, 2006. Cairo 2009

11. 1E 1547.0 - 5408 p = 2.069 c p’ = (2.318±0.005)·10-11 Camilo et al., Astrophys.J, 666, 2007 Cairo 2009

12. 4U 0142+61 • Pulse profile obtained when the observing window equals twice the apparent period (p = 8.69 s). The summing of 2 days was made with the superposition of visible pulses at the phase ~ 0.4 (red arrow). Second pulse shows up at the phase 1.4. The mean profile for one period obtained by the folding of data (lower). Cairo 2009

13. 4U 0142+61 111.23 MHz Pulse profile obtained when the observing window equals twice the apparent period (p = 8.69 s). The summing of 24 days was made with the superposition of visible pulses at the phase ~ 0.17. Second pulse shows up at the phase 1.17. The mean profile for one period obtained by the folding of data (lower). Cairo 2009

14. 4U 0142+61 111.23 MHz Cairo 2009

15. 4U 0142+61 40.96 MHz Cairo 2009

16. Relative flux density Pulse phase (ms) 2310+42 • S = 110 mJy • Р = 0,35 s • DM = 17,3 • Δt = 5,12 ms • 375 groups 470 chan = 111.88 MHz 10 chan = 109.59MHz Cairo 2009

17. Relative flux density Pulse phase (ms) 4U 0142+61 111 MHz Sum of 9 days (february – march 2006) Sum of 67 groups S/n = 9.4 109.59 – 111.88 MHz Sample = 50,99 ms Cairo 2009

18. Relative flux density Pulse phase (ms) 4U 0142+61 42 MHz Sum of 3 days (16, 18, 21.09.08) Sum of 16 groups S/n = 6.7 41.86 - 42.66 MHz Sample = 50,99 ms Cairo 2009

19. 4U 0142+61 Arrival time residuals for 4U 0142+61 Cairo 2009

20. Pulse frequency history for 4U 0142+61, Kaspi et al. 2002 Cairo 2009

21. Parameters of AXPs at 111 MHz Cairo 2009

22. Conclusions • There is radio emission from AXP, SGR and XDINS at low radio frequencies. • We have obtained independent estimates of the distances to pulsars, which are within the intervalsof distances determined using other methods. • The main difference between the radio from the X-ray pulsed emission is that the integratedradio pulses of all objects are much narrower, including AXP 4U0142+61. • The discovery of radio emission from AXP(Malofeev et al. 2001, 2005, 2007), SGR (Shitov et al.2000) together with the detection of transient pulsed radio emission from AXP XTE J1810-197, 1E 1547.0 - 5408(Camilo et al. 2006, 2007) and from radio pulsar with p = 6.7 s and p• = 1.3 ·10-12 s/s (McLaughlin et al. 2003) gives a reason to revise either the radio emission mechanisms in the “magnetar” model or the “magnetar” model itself. Cairo 2009