Discovery of radio emission from X-ray pulsar XDINS 1RXS J214303.7+065419+06
ATel #798; V. M.Malofeev (PRAO LPI, Pushchino), O. I. Malov (PRAO LPI, Pushchino), D. A. Teplykh (PRAO LPI, Pushchino), S. V. Logvinenko(PRAO LPI, Pushchino), I. I. Litvinov (PRAO LPI, Pushchino), S. B. Popov (SAI MSU, Moscow)
on 21 Apr 2006; 07:46 UT
Credential Certification: V. M. Malofeev (malofeev@prao.psn.ru)
Subjects: Radio, X-ray, Neutron Star, Pulsar
We report the detection of radio pulses from X-ray pulsar 1RXS J214303.7+065419 at the frequency 111.23 MHz. The pulsed X-ray emission with the spin period 9.437 s was discovered in March 2005 by Zane et al. (astro-ph/0503239) towards the dim isolated neutron star (XDINS) RBS 1774 using XMM-Newton observations.
Our observations were made during 66 days in October-March 2005-2006 on the Large Phased Array at Pushchino Radio Astronomy Observatory (PRAO, Russia), sensitive transit radio telescope consisting of 16384 dipoles and operating at the frequency 110.5 +/- 1.5 MHz. We use multi-channel receiver with 64 channels, where each individual channel has a width equal to 20 kHz. Pulsar signal (S/N>4) was detected in a one third of days with the integration of 20 pulses for each day. We obtained the estimation of the flux density 60+/-25 mJy. This pulsar demonstrates a complex form of the integration profile (possible there are three components) and the width of the integration profile at 50 percent of the intensity maximum is 990 ms, that is about four times less than in X-rays. There is irregular interpulse at the phase ~1/2 of period. The estimate for the dispersion measure 8+/-5 pc/cm^{3} places the pulsar at the distance ~400 pc, according to the measurements of the distances of a few surrounding pulsars (Taylor et al. 1995, unpublished data). Our distance is close to the estimate 280 pc obtained by Zane et al., 2005. We derive the period of 9.43707(10) s, and the estimate period derivative is (-1.5+/-2.2)x10^{-12} s/s on JD 2453680.0 using reliable measurements (for 10 days of observations) between JD 2453661 and JD 2453711.
This is the second case of the radio emission discovery for the XDINS. The 10.31 s X-ray pulsar 1RXS J130848.6+212708 (RBS 1223) was detected by Malofeev et al. (IAU Symp. 218, ASP Conf. Ser., p. 261, 2004; Astron Rep. 49, 242, 2005). The radio emission detection is very important, because there is no model for radio emission of such pulsars.