Looking at the black hole that powers Long Gamma Ray Bursts - - PowerPoint PPT Presentation

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Looking at the black hole that powers Long Gamma Ray Bursts - - PowerPoint PPT Presentation

Sep 16, 2023 216 likes •584 views

Looking at the black hole that powers Long Gamma Ray Bursts Antonios Nathanail Goethe University of Frankfurt Astro coffee December 2016 Gamma ray bursts Overview GRBs Gamma photons Gamma photons With BATSE 1990's Short GRBs Long GRBs

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Looking at the black hole that powers Long Gamma Ray Bursts

Antonios Nathanail Goethe University of Frankfurt

Astro coffee December 2016

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Gamma ray bursts Overview GRBs

With BATSE 1990's

Short GRBs Long GRBs Gamma photons Gamma photons

BATSE on Compton GRO

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Gamma ray bursts Overview

With BATSE 1990's

Kouveliotou et al. 1993

T wo subgroups

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Gamma ray bursts Overview Gamma ray bursts Overview ΒΑTSE Gamma ray bursts

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GRB Afterglow X-rays

Gamma-rays

Afterglow Predicted

Paczynski & Rhoads '93 Meszaros & Rees '97

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GRB Afterglow X-rays

Gamma-rays

Afterglow Predicted

Paczynski & Rhoads '93 Meszaros & Rees '97

BeppoSAX

1997 fading X-ray emission accurate measurement of position determination of distance

BeppoSAX

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GRB Afterglow X-rays

Gamma-rays X-rays

Swift 2004 -

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Slide: Gerhels

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Short Gamma ray bursts Central Engine

review Berger 2014

Open Question …

Binary Neutron star merger

 Long Lasting Magnetar ... Quickly Collapses to

Black Hole ….

 Afterglow lasting for 105 sec

Rezzolla & Kumar 2015

Ciolfi & Siegel 2014

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  • Simulating 100 SN-Type-GRBs in 1 Myr in the Milky Way

we would expect to have now ~25 “observable” magnetars.

  • HOWEVER, the expected X-ray luminosities and spin period distribution of these

GRB-magnetars CANNOT be reconciled with what observed in our magnetars.

Magnetars & Gamma-ray bursts

Rea et al. 2015

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Long Gamma ray bursts Central Engine

Core Collapse of a supermassive star

(Wolf Rayet ~ 30 MO)

Stellar Mass Black Hole formed

maximally rotating (??), Strong Magnetic fields

Hyper-accretion drives the GRB &

duration depends to surrounding mass (Ultra Long duration???)

 Jet launched, Blandford-Znajek or\and

neutrino annihilation

Extensive Literature: review Kumar & Zhang 2014

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Gendre et al.2013 Blue Super Giant Evans et al. 2014 Levan et al. 2014 Nakauchi et al. 2013

Ultra Long Gamma ray bursts Central Engine

Levan et al. 2014

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ANATOMY OF A BURST

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ANATOMY OF A BURST

Off-axis radiation Steep power law

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ANATOMY OF A BURST

Central engine extended activity

External shocks

Paczynski & Rhoads '93 Meszaros & Rees '97 ……..

Tagliaferi et al. 2005 Ghiselini et al. 2009 Zhang et al. 2014

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Small Break for theory

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Small Break for theory

Blanford & Znajek 1977 ……... Nathanail & Contopoulos 2014

magnetic flux

Black hole placed in magnetic field is loosing Energy as …….

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Small Break for theory

Nathanail & Contopoulos 2017

The importance of the ergosphere and the production of poloidal currents

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Small Break for theory … Why not a slowly rotating black hole Spin of BH

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Stellar mass black hole

slowly rotating

Small Break for theory

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Stellar mass black hole

slowly rotating

Small Break for theory

Loosing Energy as …….

Strong magnetic fields expected

Ω angular velocity

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Small Break for theory

Blanford & Znajek 1977 ……... Nathanail & Contopoulos 2014

magnetic flux

Loosing Energy as …….

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Small Break for theory Loosing Energy as …

Nathanail & Contopoulos 2015

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Can This Be observed Luminosity?

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ANATOMY OF A BURST

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Zoom in the rapid decay phase

Nathanail, Strantzalis & Contopoulos 2015

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From 343 Long GRBs 30% had this sign

Nathanail, Strantzalis & Contopoulos 2015

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Duration of a GRB depends

  • n the magnetic fjeld

strength

Nathanail, Strantzalis & Contopoulos 2015

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Easy to explain Ultra Long GRBs

Nathanail & Contopoulos 2015

Extraordinary duration ...

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From the timescale we can estimate the magnetic fjeld strength at the black hole

Nathanail & Contopoulos 2015 Nathanail, Strantzalis & Contopoulos 2015

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Comparing with Wolf Rayet observations

Magnetic fmux conservation Calculate “surface” magnetic fjeld 10 100 G

–

Inside the observable range 22 128 G

–

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The Rest 70%

The rapid decay phase is not entirely seen sparse data

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A lot of X-ray Flares

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Mass infall - Flaring Activity

X-rays

in preparation . . . (haven't done anything from last September)

Proga & Zhang 2006

magnetic barrier spin down mass infall again spin down (spin up)

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Key points

30% of Long GRBs show

signs

  • f Black Hole Spin Down

Duration of a GRB depends

  • n the magnetic fjeld

strength