Is SS 433 a misaligned ultraluminous X-ray source? Constraints from its reflected signal in the Galactic plane
Abstract
The unique supercritical accretor SS 433 is considered as a Galactic analogue of ULXs, but viewed edge-on, so the observer cannot see its collimated X-ray radiation directly. We evaluate the emission that must arise due to reflection of this putative radiation by atomic gas and molecular clouds in the Galactic plane, and compare the predicted signal with existing data for the region of interest. Assuming that the intrinsic X-ray spectrum of SS 433 is similar to that of ULXs, we obtain an upper limit of ∼ 2× 10^{39} erg/s on its angular-integrated luminosity in the 2-10 keV energy band, which weakly depends on the assumed half-opening angle, Θ_{r}, of the emission cone. In contrast, the upper limit on the apparent luminosity of SS 433 (that would be perceived by an observer looking at the system face-on) decreases with increasing Θ_{r} and is ∼ 3× 10^{40} erg/s for Θ_{r}>Θ_{p}=21 deg, where Θ_{p} is the jets precession amplitude (given that the emission cones precess in the same manner as the jets). This leaves open the possibility that SS 433 is a misaligned ULX. Further investigation of the reflection signal with the focus on the molecular clouds will improve these constraints.
- Publication:
-
The X-ray Universe 2017
- Pub Date:
- October 2017
- Bibcode:
- 2017xru..conf..111K