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

[Paolo Pani]

PS: apologies, there is a typo in the announcement. The seminar is *today
at 4pm*, not tomorrow.

On Wed, Mar 17, 2021 at 8:32 AM Paolo Pani <paolo.pani at uniroma1.it> wrote:

> Just a reminder for today's seminar:
>
> *Alejandro Cruz-Osorio *(Goethe University of Frankfurt)
> Wednesday, Mar 18th, h16:00
>
> *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.
>
> Zoom link:
> https://uniroma1.zoom.us/j/81283707469?pwd=SzkyMk5jRm0xcEN3WE5MYVh1RVFtQT09
>
> ID meeting: 812 8370 7469
> Passcode: 915450
>
> Best,
> Paolo
>
> On Fri, Mar 12, 2021 at 4:51 PM Paolo Pani <paolo.pani at uniroma1.it> wrote:
>
>> 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)
>>
>
>
> --
> 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)
>


-- 
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)

-- 
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