[2] The authors favour a scenario in which a white dwarf was shredded by a so-called intermediate-mass black hole. A white dwarf is the small, slowly-cooling core that is left behind after a star like our Sun dies. Intermediate-mass black holes are between 100 and 100 000 times more massive than the Sun. Most known black holes have masses significantly greater or lower than that, and intermediate-mass black holes remain a poorly understood type of object.
[2] The authors favour a scenario in which a white dwarf was shredded by a so-called intermediate-mass black hole. A white dwarf is the small, slowly-cooling core that is left behind after a star like our Sun dies. Intermediate-mass black holes are between 100 and 100 000 times more massive than the Sun. Most known black holes have masses significantly greater or lower than that, and intermediate-mass black holes remain a poorly understood type of object.
Probably aliens. That's my first thought on articles like this.