Search for Near-Infrared Pulsation of the Anomalous X-Ray Pulsar 4U 0142+61
Abstract
We have searched for pulsation of the anomalous X-ray pulsar (AXP) 4U 0142+61 in the K' band (λeff = 2.11μm) using the fast-readout mode of Infrared Camera and Spectrograph (IRCS) at the Subaru 8.2 m telescope. We found no significant signal at the pulse frequency expected by the precise ephemeris based on an X-ray monitoring observation with RXTE. Nonetheless, we obtained the best upper limit of 17% (90% C.L.) for the root-mean-square pulse fraction in the K' band. Combined with the i' band pulsation (Dhillon et al. 2005, MNRAS, 363, 609), the slope of the pulsed component (Fν∝να in units of Jy) was constrained to α > -0.87 (90% C.L.) for an interstellar extinction of AV = 3.5.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- February 2009
- DOI:
- 10.1093/pasj/61.1.51
- arXiv:
- arXiv:0809.2638
- Bibcode:
- 2009PASJ...61...51M
- Keywords:
-
- stars: neutron;
- stars: pulsars: individual (4U 0142+61);
- Astrophysics
- E-Print:
- 11 pages, 3 figures, Accepted for publication in PASJ