Synopsis

Dark Matter Blowing Like a Hurricane  

Physics 11, s130
The dark matter in our stellar neighborhood may be moving at high speed, which might produce a signature that future dark matter searches could detect.  
C. O'Hare; NASA/Jon Lomberg

The cosmic weather forecast calls for strong dark matter winds in our region of the Galaxy. The prediction is based on a new study of a nearby collection of stars that are all moving in the same direction. This so-called S1 stream is believed to be the remnant of a dwarf galaxy that was swallowed by the Milky Way billions of years ago. The dark matter from this long-gone galaxy may be blowing past us at roughly 500 km/s, according to the study’s authors. Such a “dark matter hurricane” might leave a detectable imprint in data from dark matter searches.

The S1 stream was identified last year in an ongoing billion-star survey by the Gaia satellite. This is not the first stellar stream—in fact, astronomers have previously detected around 30 of these moving throngs in our Galaxy. The accepted understanding is that each of these streams is the debris of a small galaxy that crashed into the Milky Way.

The unique interest in S1 stems from the fact that its path crosses that of the Sun. Ciaran O'Hare from the University of Zaragoza, Spain, and colleagues calculated the effect of S1 on the dark matter in our region. The team considered different models for the density and distribution of the inflowing dark matter from the S1 progenitor galaxy. They then predicted possible signatures of this fast-moving population in searches for dark matter. Current detectors looking for weakly interacting massive particles (WIMPs)—one widely discussed form of dark matter—probably won’t see any effect from S1, but future WIMP detectors might. The chances are better for axion detectors, as the energy spectrum from axionic dark matter should exhibit a broad bump with an additional narrow peak if the S1 hurricane is truly buffeting our shores.

This research is published in Physical Review D.

–Michael Schirber

Michael Schirber is a Corresponding Editor for Physics based in Lyon, France.


Subject Areas

CosmologyAstrophysics

Related Articles

Do Merging Dwarf Galaxies Explain a Peculiar Gravitational-Wave Detection?   
Astrophysics

Do Merging Dwarf Galaxies Explain a Peculiar Gravitational-Wave Detection?   

The hard-to-explain masses of two coalescing black holes could be accounted for if they were the central black holes in two distant, tiny galaxies that merged. Read More »

Compiling Messages from Neutron Stars
Astrophysics

Compiling Messages from Neutron Stars

The combination of gravitational-wave and x-ray observations of neutron stars provides new insight into the structure of these stars, as well as new confirmation of Einstein’s theory of gravity. Read More »

Probing the Skin of a Lead Nucleus
Astrophysics

Probing the Skin of a Lead Nucleus

Researchers make the most precise measurement yet of the neutron distribution in a heavy nucleus, with implications for the structure of neutron stars. Read More »

More Articles