The hypersoft state of Cyg X-3: A key to jet quenching in X-ray binaries?
Koljonen Karri  2, 1@  , Thomas Maccarone  3@  , Michael Mccollough  4@  , Sergei Trushkin  6, 5@  , Guy Pooley  7@  , Mark Gurwell  4@  
2 : Aalto University Metsähovi Radio Observatory  (MRO)  -  Website
Metsähovintie 114, FI-02540 Kylmälä -  Finland
1 : Finnish Centre for Astronomy with ESO  (FINCA)  -  Website
Väisäläntie 20, FI-21500 Piikkiö -  Finland
3 : Department of Physics [Texas Tech]  -  Website
Texas Tech University Broadway and Boston Lubbock, TX 79409-1042 -  United States
4 : Harvard-Smithsonian Center for Astrophysics  (CfA)  -  Website
Cambridge, MA 02138 -  United States
6 : Kazan Federal University, Russia  (KPFU)  -  Website
Kazan Federal University 18 Kremlyovskaya str Kazan, 420008 Russian Federation -  Russia
5 : Special Astrophysical Observatory of the Russian Academy of Sciences  (SAO RAS)  -  Website
Nizhnij Arkhyz, Zelenchukskiy region, Karachai-Cherkessian Republic, Russia 369167 -  Russia
7 : Cavendish Laboratory - University of Cambridge  -  Website
Astrophysics Group Department of Physics Cavendish Laboratory University of Cambridge The Old Schools Trinity Lane Cambridge CB2 1TN -  United Kingdom

Cyg X-3 is a unique microquasar in the Galaxy hosting a Wolf-Rayet companion orbiting a compact object that most likely is a low-mass black hole. The unique source properties are likely due to the interaction of the compact object with the heavy stellar wind of the companion. In this presentation I will concentrate on a very specific period of time in the evolution of the binary prior to the massive outbursts observed from the source. During this period Cyg X-3 is in a so-called hypersoft state, where the radio and hard X-ray fluxes are found to be at their lowest values (or non-detected), the soft X-ray flux is at its highest values, and sporadic gamma-ray emission is attributed to the onsets and ends of this period. I will present the recent results obtained by a multiwavelength campaign during the hypersoft state including Swift and NuSTAR pointing observations in the X-rays and broadband radio monitoring by SMA, AMI-LA and RATAN-600. Motivated by the observational results, I will discuss a scenario where the jet production gets completely turned off, and show that a similar sequence of events might take place in the accretion wind source GRO J1655-40.


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