The existence of dark matter is probably one of the fundamental mysteries of modern science and unraveling its nature has become one of the primary goals of modern Physics. Despite representing 85% of all matter in the Universe, we do not know what it is. In its simplest description, it is made up of particles that interact with each other and with ordinary matter only through gravity. However, this description does not correspond to any physical model. Finding out what dark matter is requires finding evidence of some kind of interaction of dark matter that goes beyond gravity. In our work

The transient Swift J1727.8-162 is the latest member of the X-ray binary black hole family to be discovered. They are formed by a black hole and a low-mass star whose gas is stripped off and accreted to the black hole via an accretion disc. The high temperature of the accretion disc makes it shine in all energy bands up to X-rays, and is particularly bright during epochs known as outbursts. In this novel study, published just a few months after the discovery of the system, we present 20 epochs of optical spectroscopy obtained with the GTC-10.4m telescope. The spectra cover the main accretion

The properties of blue supergiants are key for constraining the end of the main sequence phase, a phase during which massive stars spend most of their lifetimes. The lack of fast-rotating stars below 21.000K, a temperature around which stellar winds change in behaviour, has been proposed to be caused by enhanced mass-loss rates, which would spin down the star. Alternatively, the lack of fast-rotating stars may be the result of stars reaching the end of the main sequence. Here, we combine newly derived estimates of photospheric and wind parameters, wind terminal velocities from the literature