A black hole detected in the young massive LMC cluster NGC 1850

Understand

We report the detection of a black hole (NGC 1850 BH1) in the $\sim$100 Myr-old massive cluster NGC~1850 in the Large Magellanic Cloud.

• It is in a binary system with a main-sequence turn-off star (4.9 $\pm$ 0.4 M${_\odot}$), which is starting to fill its Roche Lobe and becoming distorted.
• Using 17 epochs of VLT/MUSE observations we detected radial velocity variations exceeding 300 km/s associated to the target star, linked to the ellipsoidal variations measured by OGLE-IV in the optical bands.
• Under the assumption of a semi-detached system, the simultaneous modelling of radial velocity and light curves constraints the orbital inclination of the binary to ($38 \pm 2$)$^{\circ}$, resulting in a true mass of the unseen companion of $11.1_{-2.4}^{+2.1}$ $M_{\odot}$.