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PoS(INTEGRAL2016)076

EXO 2030+375 Restarts in Reverse

P. Kretschmar, F. Fuerst, C.A. Wilson-Hodge, P. Blay, J. Kajava, J. Alfonso-Garzón, M. Kühnel, I. Kreykenbohm, J. Wilms, P.A. Jenke, K. Pottschmidt

in 11th INTEGRAL Conference Gamma-Ray Astrophysics in Multi-Wavelength Perspective

Contribution: pdf

Abstract

The Be X-ray binary pulsar EXO 2030+375, first detected in 1985, has shown a significant de- tected X-ray outburst at nearly every periastron passage of its 46-day orbit for the past 25 years, with one low state accompanied by a torque reversal in the 1990s. In early 2015 the outbursts progressively became fainter and less regular while the monotonic spin-up flattened. At the same time a decrease in the Hα line equivalent width was reported, indicating a change in the disk surrounding the mass donor.

In order to explore the source behaviour in the poorly explored low-flux state with a possible tran- sition to a state of centrifugal inhibition of accretion we have undertaken an observing campaign with Swift/XRT, NuSTAR and the Nordic Optical Telescope (NOT). This conference contribution reports the preliminary results obtained from our campaign.