[astroseminar at Sapienza] Two gravity theory webinars next week (March 15, 12h and March 18 16h)

[Paolo Pani]

Next week there will be *two* gravity-theory webinars:

*1. Danny Laghi* and *Gregorio Carullo* (University of Pisa)
Monday, Mar 15th, h12pm

*Title*: *Quantum black hole spectroscopy: probing the quantum nature of
the black hole area using LIGO-Virgo ringdown detections.*

*Abstract*: We present an observational investigation of the hypothesis
that the area of a black hole is quantised in multiples of the Planck area,
relying on a recently-proposed heuristic ringdown model built from the
Bekenstein-Mukhanov quantisation conjecture. The theoretical principles of
the model, along with some of its possible extensions, are reviewed.
Leveraging on the increasing number of black hole merger detections from
the LIGO and Virgo collaborations, we present a test of the conjecture by
combining all the available information from the black hole population
included in the GWTC-2 catalog. A time-domain analysis, based on the pyRing
software, is employed to quantify the evidence for the presence of
signatures of the area quantisation in the ringdown signals. We also
discuss the exciting detection prospects of effects due to the area
quantisation with future observations from current ground-based detectors
at their design sensitivity.




*2.* *Alejandro Cruz-Osorio *(Goethe University of Frankfurt)
Wednesday, Mar 18th, h4pm

*Title*: General relativistic simulations of the common-envelope evolution

*Abstract*: The common-envelope scenario is encountered when a black
hole/neutron star moves in the stellar envelope of a red supergiant star as
a  consequence the orbital energy and angular momentum are transferred to
the gas modifying the quasi-circular orbit of the binary and reducing the
inspiral timescale. We will discuss the results from general relativistic
simulations of a simplified model of the interaction between a stellar
black hole and the envelope of a red supergiant star. We have considered a
non-rotating black hole moving supersonically in a medium with regular but
different density gradients. The simulations reveal that the supersonic
motion always rapidly reaches a stationary state and it produces a shock
cone in the downstream part of the flow. Together with the phenomenological
aspects of the accretion flow, we have also quantified the rates of
accretion of mass and momentum onto the black hole. Simple analytic
expressions have been found for the rates of accretion of mass, momentum,
drag force, and bremsstrahlung luminosity. Our results have shown that the
inspiral time can be reduced from 200years to 0.4years in the common
envelope-phase of the binary system.



For both events, the Zoom link is
https://uniroma1.zoom.us/j/81283707469?pwd=SzkyMk5jRm0xcEN3WE5MYVh1RVFtQT09
ID meeting: 812 8370 7469
Passcode: 915450

Calendar available here:
 https://calendar.google.com/calendar/u/1?cid=Y191MGo3bG9pYzE1bjBxdGFhN3A4MTlzNDg2Y0Bncm91cC5jYWxlbmRhci5nb29nbGUuY29t
<https://calendar.google.com/calendar/u/1?cid=Y191MGo3bG9pYzE1bjBxdGFhN3A4MTlzNDg2Y0Bncm91cC5jYWxlbmRhci5nb29nbGUuY29t>

Have a nice weekend,
Paolo

-- 
Paolo Pani
Associate Professor
ERC StG Fellow, DarkGRA project
Junior Fellow, Scuola Superiore di Studi Avanzati Sapienza

Physics Department (Marconi Building), 3rd floor, room 334
Sapienza University of Rome
Piazzale Aldo Moro 5 - 00185 Rome (Italy)
+39 06 4991 4472 (int 24472)

-- 
________________________________________________________
Le informazioni 
contenute in questo messaggio di posta elettronica sono strettamente 
riservate e indirizzate esclusivamente al destinatario. Si prega di non 
leggere, fare copia, inoltrare a terzi o conservare tale messaggio se non 
si è il legittimo destinatario dello stesso. Qualora tale messaggio sia 
stato ricevuto per errore, si prega di restituirlo al mittente e di 
cancellarlo permanentemente dal proprio computer.
The information contained 
in this e mail message is strictly confidential and intended for the use of 
the addressee only.  If you are not the intended recipient, please do not 
read, copy, forward or store it on your computer. If you have received the 
message in error, please forward it back to the sender and delete it 
permanently from your computer system.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists2.roma1.infn.it/pipermail/astroseminar/attachments/20210312/d85c5694/attachment.html