Relativistic baryonic jets from an ultraluminous supersoft X-ray source

Liu, Ji-Feng; Bai, Yu; Wang, Song; Justham, Stephen; Lu, You-Jun; Gu, Wei-Min; Liu, Qing-Zhong; di Stefano, Rosanne; Guo, Jin-Cheng; Cabrera-Lavers, A.; Álvarez, P.; Cao, Yi; Kulkarni, Shri
Bibliographical reference

Nature, Volume 528, Issue 7580, pp. 108-110 (2015).

Advertised on:
12
2015
Journal
Number of authors
13
IAC number of authors
2
Citations
39
Refereed citations
36
Description
The formation of relativistic jets by an accreting compact object is one of the fundamental mysteries of astrophysics. Although the theory is poorly understood, observations of relativistic jets from systems known as microquasars (compact binary stars) have led to a well established phenomenology. Relativistic jets are not expected to be produced by sources with soft or supersoft X-ray spectra, although two such systems are known to produce relatively low-velocity bipolar outflows. Here we report the optical spectra of an ultraluminous supersoft X-ray source (ULS) in the nearby galaxy M81 (M81 ULS-1; refs 9, 10). Unexpectedly, the spectra show blueshifted, broad Hα emission lines, characteristic of baryonic jets with relativistic speeds. These time-variable emission lines have projected velocities of about 17 per cent of the speed of light, and seem to be similar to those from the prototype microquasar SS 433 (refs 11, 12). Such relativistic jets are not expected to be launched from white dwarfs, and an origin from a black hole or a neutron star is hard to reconcile with the persistence of M81 ULS-1’s soft X-rays. Thus the unexpected presence of relativistic jets in a ULS challenges canonical theories of jet formation, but might be explained by a long-speculated, supercritically accreting black hole with optically thick outflows.
Related projects
Project Image
Morphology and dynamics of the Milky Way
This project consists of two parts, each differentiated but both complementary: morphology and dynamics. Detailed study of the morphology of the Milky Way pretends to provide a data base for the stellar distribution in the most remote and heavily obscured regions of our Galaxy, through the development of semiempirical models based on the
Martín
López Corredoira