[seminar] Astro Journal Club on June 7th

[Lana Ceraj]

Dear all, 

Astro Journal club starts on Wednesday at 3 p.m. (sharp) in the seminar room F-201 of the Physics Department. 

Presenter: Ivan Delvecchio, dr. sc.

Title: An intermediate-mass black hole in the centre of the globular cluster 47 Tucanae

Authors: Kiziltan et al. (2017)

Abstract: 
Intermediate mass black holes play a critical role in understanding the evolutionary connection between stellar mass and super-massive black holes. However, to date the existence of these species of black holes remains ambiguous and their formation process is therefore unknown. It has been long suspected that black holes with masses 102−104M⊙ should form and reside in dense stellar systems. Therefore, dedicated observational campaigns have targeted globular cluster for many decades searching for signatures of these elusive objects. All candidates found in these targeted searches appear radio dim and do not have the X-ray to radio flux ratio predicted by the fundamental plane for accreting black holes. Based on the lack of an electromagnetic counterpart upper limits of 2060M⊙ and 470M⊙ have been placed on the mass of a putative black hole in 47 Tucanae (NGC 104) from radio and X-ray observations respectively. Here we show there is evidence for a central black hole in 47 Tuc with a mass of 
M∙∼2300M⊙+1500−850 when the dynamical state of the globular cluster is probed with pulsars. The existence of an intermediate mass black hole in the centre of one of the densest clusters with no detectable electromagnetic counterpart suggests that the black hole is not accreting at a sufficient rate and therefore contrary to expectations is gas starved. This intermediate mass black hole might be a member of electromagnetically invisible population of black holes that are the elusive seeds leading to the formation of supermassive black holes in galaxies. 

Link to paper: https://arxiv.org/abs/1702.02149
 
If you have recently read interesting astrophysics paper you would like to present, please contact me via e-mail: lceraj at phy.hr <mailto:lceraj at phy.hr>

See you on Wednesday.

Cheers,
Lana
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