Dark matter–baryons separation at the lowest mass scale: the Bullet Group
Publication date: 07 June 2014
Authors: F. Gastaldello et al.
Journal: Monthly Notices of the Royal Astronomical Society
Copyright: Oxford University Press
We report on the X-ray observation of a strong lensing selected group, SL2S J08544-0121, with a total mass of 2.4 ± 0.6 × 1014 MSun which revealed a separation of 124 ± 20 kpc between the X-ray emitting collisional gas and the collisionless galaxies and dark matter (DM), traced by strong lensing. This source allows to put an order of magnitude estimate to the upper limit to the interaction cross-section of DM of 10 cm2 g−1. It is the lowest mass object found to date showing a DM–baryons separation, and it reveals that the detection of bullet-like objects is not rare and confined to mergers of massive objects opening the possibility of a statistical detection of DM–baryons separation with future surveys.Link to publication