Project A

Wind-blown bubbles around accreting neutron stars and black holes

Marianne Heida & María Díaz Trigo

(email advisors)

How do accreting stellar-mass black holes and neutron stars affect their environment? Search for signs of winds and jets blowing bubbles in the interstellar medium.

Accretion of material from a donor star onto stellar-mass black holes and neutron stars in so-called X-ray binaries powers the most luminous phenomena in the Universe. Associated with accretion onto such compact objects is the existence of outflows, both in the form of uncollimated winds or highly collimated relativistic jets.  

We expect the environments of X-ray binaries to be affected by the expelled material, energy and momentum of such outflows. Indeed, parsec-scale bubbles have been observed around ultra-luminous X-ray sources, extremely bright, extragalactic X-ray binaries accreting well above the Eddington limit. However, in our Galaxy such bubbles remain elusive despite extensive searches. The goal of this project is to search for wind-inflated bubbles around Galactic X-ray binaries that are persistently accreting at very high rates (near or above the Eddington limit) and therefore known to expel winds from the accretion disc around the compact object. 

In this project you will use existing data from the superCOSMOS H-alpha Survey to construct Halpha images of the surroundings of eight persistent X-ray binaries, seven neutron stars and one black hole. You will search these images for signs of wind-blown bubbles around these objects and if you find any, measure their sizes and use data from WHAM-SS to study their kinematics. This study has the potential to reveal the first wind-blown bubbles around Galactic X-ray binaries, which would be an extremely exciting result and teach us a lot about the ways these objects shape their environments. 

#Xraybinary #photometry #neutronstar #blackhole #accretion #outflows 

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