Multiwavelength (Radio, X‐Ray, and γ‐Ray) Observations of the γ‐Ray Binary LS I +61 303

Abstract

We present the results of the first multiwavelength observing campaign on the\nhigh-mass X-ray binary LS I +61 303 comprising observations at the TeV regime\nwith the MAGIC telescope, along with X-ray observations with Chandra, and radio\ninterferometric observations with the MERLIN, EVN and VLBA arrays, in October\nand November 2006. From our MERLIN observations, we can exclude the existence\nof large scale (~100 mas) persistent radio-jets. Our 5.0 GHz VLBA observations\ndisplay morphological similarities to previous 8.4 GHz VLBA observations\ncarried out at the same orbital phase, suggesting a high level of periodicity\nand stability of the processes behind the radio emission. This makes it\nunlikely that variability of the radio emission is due to the interaction of an\noutflow with variable wind clumps. If the radio emission is produced by a\nmilliarcsecond scale jet, it should also show a stable, periodic behavior. It\nis then difficult to reconcile the absence of a large scale jet (~100 mas) in\nour observations with the evidence of a persistent relativistic jet reported\npreviously. We find a possible hint of temporal correlation between the X-ray\nand TeV emissions and evidence for radio/TeV non-correlation, which points to\nthe existence of one population of particles producing the radio emission and a\ndifferent one producing the X-ray and TeV emissions. Finally, we present a\nquasi-simultaneous energy spectrum including radio, X-ray and TeV bands.\n