Dear Astro-Lunchers,
After a long break, we are going to have AstroParticle Lunch at 11:45 am EST (5:45 pm Spanish time) this Friday! As a quick reminder, our Lunch will be pure virtual this week.
We are very excited that Marc Oncins from ICC, University of Barcelona, will join us as a guest and talk about his work on the primordial black hole captured by stars and its consequences. See more details below!
Title: Primordial black holes captured by stars and induced collapse to low-mass stellar black holes
[https://arxiv.org/abs/2205.13003]
Abstract:
Primordial black holes in the asteroid-mass window (∼10−16 to 10−11 M☉), which might constitute all the dark matter, can be captured by stars when they traverse them at low enough velocity. After being placed on a bound orbit during star formation, they can repeatedly cross the star if the orbit is highly eccentric, slow down by dynamical friction, and end up in the stellar core. The rate of these captures is highest in halos of high dark matter density and low-velocity dispersion when the first stars form at redshift z∼20. We compute this capture rate for low-metallicity stars of 0.3 to 1M☉ and find that a high fraction of these stars formed in the first dwarf galaxies would capture a primordial black hole, which would then grow by accretion up to a mass that may be close to the total star mass. We show the capture rate of primordial black holes does not depend on their mass over this asteroid-mass window and should not be much affected by external tidal perturbations. These low-mass stellar black holes could be discovered today in low-metallicity, old binary systems in the Milky Way containing a surviving low-mass main-sequence star or a white dwarf, or via gravitational waves emitted in a merger with another compact object. No mechanisms in standard stellar evolution theory are known to form black holes of less than a Chandrasekhar mass, so detecting a low-mass black hole would fundamentally impact our understanding of stellar evolution, dark matter, and the early Universe.
After Marc’s talk, Po-Wen will present my recent paper in collaboration with Ivan, John, Todd, and Chris[https://arxiv.org/abs/2206.12426]. Through this paper, we show how supernovae could offer powerful probes of neutrino self-interactions by their neutrino signal duration.
A list of selected papers can also be found on our websitehttps://sites.google.com/site/ccappastrolunch/. Feel free to reach out to us if you want to discuss any paper you found interesting! We look forward to seeing you soon : )