Black Holes: Nobel Prize in Physics 2020 Julien Woillez (ESO) Nobel Prize in Physics 2020

Roger Penrose Reinhard Genzel & Andrea Ghez “for the discovery that black hole formation “for the discovery of a is a robust prediction supermassive compact of the general theory object at the centre of our of relativity” galaxy”

Roger Penrose Reinhard Genzel Andrea Ghez ’60s Quasi Stellar Objects

Very small, very far, ultra-luminous, and therefore very massive

Schmidt 1963 3C 273 ESA/Hubble Picture of the Week

Hubble 1929 ’60s Accretion disks and super massive black holes

Electromagnetic radiation

Accreting matter

A very efficient central engine converts gravitational energy into EM radiation

Salpeter 1964, Zeldovich & Novikov 1965 ’60s What about non-active galaxies, like ours?

Is a starved supermassive black hole there?

Lynden-Bell, 1969 Lynden-Bell & Rees, 1971 ’80s Unification of Active Galactic Nuclei

All Active Galaxies have the same black and accretion disk central engine

Broad emission lines in polarized light

Antonucci & Miller, 1985 ’80s What about our galaxy?

Galactic Center M87

No bright counterpart in Radio, X-ray, IR

No jet M87 VLA EHT 2019

Owens, Biretta, Eilek ’80s Birth of infrared astronomy

Wollman+77, Lacy, Townes, Hollenbach 82, … ’90s Near-IR astronomy at La Silla Observatory (Chile)

Adaptive Optics (ESO 3.6m) Speckle Imaging (NTT 3.58 m)

3D spectroscopy (MPG/ESO 2.2 m) ’90s

~10” ( 10 light years ) Speckle imaging Short exposuresShort exposures Long Speckle imaging

Weigelt 1977

http://www.mpifr-bonn.mpg.de/div/ir-interferometry/movie/speckle/specklemovie.html Labeyrie et al. 1974 ’90s Speckle imaging

Eckart+ 1992

Eckart & Genzel 1997 ’90s 10-meter-class telescope era starts in the US

Keck I first science in 1993 Keck II first light in 1996 ’90s First stellar orbits

Ghez+ 1998

50 mas angular resolution

Ghez+ 2000 ’90s Beyond the atmospheric turbulence limit Adaptive Optics

COME-ON+, SHARPII, ADONIS

Rigaut+, Beuzit+, Hubin+, Bonnacini+, Lacombes+, Brandl+, Eisenhauer+

Courtesy of ESO/L Calcada

Clenet+01 ’90s Birth of Very Large Telescope

First science between 1998 ~ 2000 ’00s Adaptive optics first light at Keck Observatory

1999: First light for Keck II Adaptive Optics

Wizinowich+2000 2002 S2 a 15.2-year orbit around SgrA*

Speckle imaging La Silla NTT

Adaptive optics imaging Paranal VLT (NACO instrument)

Schödel+ 2002 2002 (-16 years) The S2 count down

S2 becomes the best test particle! 16 years to go

2002 2018

Schödel+ 2002 2002 (-16 years) Adaptive Optics and Spectroscopy

Ghez+2003 Redshift gives radial velocity 2003 (-15 years) The variable IR counter part of SgrA*

Genzel+2003 Ghez+2004

17 minutes period! 2004 (-14 years) Laser guide star Adaptive Optics

Wizinowich+ 2006

Ghez+ 2005 Dancing stars

SINFONI 18.08.04: K(75 mas) 0.6

21 22 NACO 10.06.04: H (40mas) 0.4 26 15 W6

S12 ) 0.2 9 S08

S5 arcsec

* ( * S4 S14 S2 Astrometry S6 S13 Spectroscopy

SgrA 0 S7 S7 S17 8

offset fromoffset -0.2 - 7 S1 Dec. S8 14.7 10 S9 19 -0.4 S9 S10 25 S013 16 0.5” (23 light days) S19 S11 23 -0.6 0.6 0.4 0.2 0 -0.2 -0.4 -0.6

R.A.-offset from SgrA* (arcsec)

Schödel+02, Ghez+03,05,08, Eisenhauer+03,05, Paumard+07, Do+09, Gillessen+09,17, Meyer+12, Boehle+16, Fritz+16, Habibi+17 ... Gillessen+12,13,18, Phifer+14, Witzel+14, Pfuhl+15, Valencia-S.+15, Shahzamanian+16, Zajaček+17, Plewa+17 Dancing stars 2005 (-13 years) Better than adaptive optics: stellar interferometry

GRAVITY instrument Project starts 2007 (-11 years) First light 2015 (-3 years)

GRAVITY collaboration+ 2017 2006 (-12 years) Keck Interferometer / ASTRA

Keck Interferometer was shut down in 2012 (-6 years)

Woillez, Wizinowich+ 2014 2018 (-0 years) 1000x more sensitive than earlier interferometers

20-50 µas orbit precision

June Motion of S2 seen from 3 day to day 1 30 27 24

Peri 19 May 4 2 28 26 April May/June 2018 May Moving at 8000 km/s

50 mas GRAVITY collaboration+18 Measurement of Gravitational Redshift

Einstein

GRAVITY collaboration+18 Newton Precise Measurement of Schwarzschild Precession

Schwarzschild

GRAVITY collaboration+20 o o 2 Jul 22 2018 flare, MJD=58321.9954 R=7 R a=0 i=160 =160  =1.2 g r 100

50 100

0 0 -50 Even Closer – Orbital Motion Close to the Last

-100 -100 Stable Orbit

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time (mins) x-offset(as) GRAVITY collaboration+18 Mass of SgrA* Concentrated within few Schwarzschild Radii

R/RS 1 10 102 103 104 105 106 107

old stars 107 clockwise disc

flare S2 S-stars CND 106

5 10 Extended mass radio size upper limit

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103 enclosed enclosed (solar masses)mass

102 0.001 0.01 0.1 1 10 Radius (parsec) GRAVITY collaboration+18 Sensitivity, Sensitivity, Sensitivity, … Accuracy, Accuracy, Accuracy, … Contrast, Contrast, Contrast, …

GRAVITY+ Faint All Sky Milli Arcsecond Imaging and Micro Arcsecond (Spectro) Astrometry

KU Lueven