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The detection of variability from the candidate IR counterpart to the Anomalous X-ray Pulsar 1E1048.1-5937

G. L. Israel·S. Covino·L. Stella·S. Campana·G. Marconi·S. Mereghetti·R. Mignani·I. Negueruela·T. Oosterbroek·A. N. Parmar·L. Burderi·L. Angelini
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Abstract

We report on the detection of variability from the proposed IR counterpart to the Anomalous X-ray Pulsar (AXP) 1E1048.1-5937 based on Chandra and ESO optical/IR deep observations carried out in 2001-2002. Within the narrow Chandra uncertainty region for 1E1048.1-5937 we found only one relatively faint (J=22.1+/-0.3, J-Ks=2.4) source, while the recently proposed IR counterpart was not detected down to a limiting Ks magnitude of about 20.7 (3sigma confidence level). This implies a remarkable IR brightening of this object, Delta Ks>1.3, on a timescale of about 50 days. Although our knowledge of the IR properties of AXPs is rather limited (there is only another source, 1E2259+586, for which IR variability has been detected), the observed IR variability of the proposed counterpart strengthens its association with 1E1048.1-5937. Our results make the IR (and presumably optical) variability a likely common characteristic of AXPs, and provide new constraints on this class of objects.

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G. L. Israel, S. Covino, L. Stella, S. Campana, G. Marconi, S. Mereghetti, R. Mignani, I. Negueruela, T. Oosterbroek, A. N. Parmar, L. Burderi, L. Angelini. 2002-09-28. The detection of variability from the candidate IR counterpart to the Anomalous X-ray Pulsar 1E1048.1-5937. https://doi.org/10.1086/345612

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