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We investigate the impact of stellar rotation on the formation of black holes (BHs), by means of our population-synthesis code SEVN. Rotation affects the mass function of BHs in several ways. In massive metal-poor stars, fast rotation reduces the minimum zero-age main sequence (ZAMS) mass for a star to undergo pair instability and pulsational pair instability. Moreover, stellar winds are enhanced by rotation, peeling-off the entire hydrogen envelope. As a consequence of these two effects, the maximum BH mass we expect from the collapse a rotating metal-poor star is only $sim{}45$ M$_odot$, while the maximum mass of a BH born from a non-rotating star is $sim{}60$ M$_odot$. Furthermore, stellar rotation reduces the minimum ZAMS mass for a star to collapse into a BH from $sim{}18-25$ M$_odot$ to $sim{}13-18$ M$_odot$. Finally, we have investigated the impact of different core-collapse supernova (CCSN) prescriptions on our results. While the threshold value of compactness for direct collapse and the fallback efficiency strongly affect the minimum ZAMS mass for a star to collapse into a BH, the fraction of hydrogen envelope that can be accreted onto the final BH is the most important ingredient to determine the maximum BH mass. Our results confirm that the interplay between stellar rotation, CCSNe and pair instability plays a major role in shaping the BH mass spectrum.
If a black hole has a low spin value, it must double its mass to reach a high spin parameter. Although this is easily accomplished through mergers or accretion in the case of supermassive black holes in galactic centers, it is impossible for stellar-
Models of pair-instability supernovae (PISNe) predict a gap in black hole (BH) masses between $sim 45M_odot-120M_odot$, which is referred to as the upper BH mass-gap. With the advent of gravitational-wave astrophysics it has become possible to test t
We build an evolution model of the central black hole that depends on the processes of gas accretion, the capture of stars, mergers as well as electromagnetic torque. In case of gas accretion in the presence of cooling sources, the flow is momentum-d
We suggest in this note that spider systems are the naturally expected progenitors of the highest neutron star masses, and possibly low-mass black holes, based on their long-term evolutionary features and actual mass measurements.
We aim to study the progenitor properties and expected rates of the two lowest-mass binary black hole (BH) mergers, GW 151226 and GW 170608, detected within the first two Advanced LIGO-Virgo runs, in the context of the isolated binary-evolution scena