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 (${\lambda }_{\mathrm{eff}}=2.11$ $\mu$m) using the fast-readout mode of IRCS at the Subaru 8.2-m telescope. We found no significant signal at the pulse frequency expected by the precise ephemeris obtained by the X-ray monitoring observation with RXTE. Nonetheless, we obtained a best upper limit of 17% (90% C.L.) for the root-mean-square pulse fraction in the K' band. Combined with i' band pulsation (Dhillon et al. 2005), the slope of the pulsed component ($F_{\nu }\propto {\nu }^{\alpha }$) was constrained to $\alpha >-0.87$ (90% C.L.) for an interstellar extinction of $A_V=3.5$.

11 pages, 3 figures, Accepted for publication in PASJ

References in corpus (7)

• A Debris Disk Around An Isolated Young Neutron Star
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• Anomalous X-ray pulsars: Persistent States with Fallback Disks
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Cited by in corpus (3)

• Optical, ultraviolet, and infrared observations of isolated neutron stars
• A Mid-Infrared Counterpart to the Magnetar 1E 2259+586
• A white dwarf merger as progenitor of the anomalous X-ray pulsar 4U 0142+61?