Marek Kowalski PTF, Szczecin Exploding Stars, Cosmic Acceleration and Dark Energy Supernova 1994D Marek Kowalski Humboldt-Universität zu Berlin Szczecin,

Marek Kowalski PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

Marek Kowalski PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

Marek Kowalski PTF, Szczecin History Einstein, 1916: General Relativity

Marek Kowalski PTF, Szczecin History EnergyCurvature Einstein, 1916: General Relativity

Marek Kowalski PTF, Szczecin General Relativity: Gravitational bending of light

Marek Kowalski PTF, Szczecin General Relativity: Gravitational bending of light Abell 2218: A Galaxy Cluster Lens, Andrew Fruchter et al. (HST)

Marek Kowalski PTF, Szczecin General Relativity: The Universe can have curvature

Marek Kowalski PTF, Szczecin Einstein, 1916: General Relativity Curvature I want a static Universe - I’ll add a cosmological constant Energy

Marek Kowalski PTF, Szczecin Einstein, 1916: General Relativity History continues...

Marek Kowalski PTF, Szczecin History continues... Edwin Hubble, 1929: Redshift of Galaxies

Marek Kowalski PTF, Szczecin Redshift of spectral lines: “Doppler effect” The larger the distance to a Galaxy, the faster it is flying away from us: velocity = H 0 x distance

Marek Kowalski PTF, Szczecin Hubble: The Universe is expanding! Einstein: The cosmological constant was the biggest Blunder of my life!

Marek Kowalski PTF, Szczecin History continues... Edwin Hubble, 1929: Redshift of Galaxies

Marek Kowalski PTF, Szczecin 10 years ago: Detection of the accelerated Universe by two teams of astronomers History continues... The cosmological constant might be back! B. Schmidt S. Perlmutter

Marek Kowalski PTF, Szczecin

Marek Kowalski PTF, Szczecin Outline  A brief history of Cosmology  Supernova observations today  A mysteries: Dark Energy 3

Marek Kowalski PTF, Szczecin

Marek Kowalski PTF, Szczecin 1 Supernova Type Ia Type Ia supernovae (SNe Ia) provide bright “standard candle” that can be used to construct a Hubble diagram. Accretion sends mass of white dwarf star to Chandrasekhar limit leading to gravitational collapse and a thermo-nuclear explosion of its outer layers. Each one is a strikingly similar explosion event with nearly the same peak intensity.

Marek Kowalski PTF, Szczecin “Standard” Candles Nearby supernovae used to study SNe light curve (z<0.1) Brightness not quite standard Stretching the timescale: Correcting the Brightness: Intrinsically brighter SNe have wider lightcurves.

Marek Kowalski PTF, Szczecin Spectra used for Identification & Redshift determination

Marek Kowalski PTF, Szczecin Searching for Supernovae Reference new picture difference SN-Candidate For example with the: Canadian-French-Hawaii Telescope: 3.6 m MegaCam Camera: pixels

Marek Kowalski PTF, Szczecin Sloan Digital Sky Survey

Marek Kowalski PTF, Szczecin SNe at large Redshifts (z>1) Observations from Space with the Hubble Space Telescopes: 15

Marek Kowalski PTF, Szczecin SNe Type Ia & Acceleration of the Universe Normalization fainter then expected     M slightly brighter   M fainter Supernova Cosmology Project Kowalski et al., Ap.J. (2008)

Marek Kowalski PTF, Szczecin 18 Perlmutter et al., 1999 Cosmological Parameter  MM SNe + BAO + CMB Curvature: CMB: Komatsu et al BAO: Eisenstein et al., 2005  MM Kowalski et al., 2008 Marek Kowalski 7. Juli 2008

Dark Energy: 65% Dark Matter: 30% 70% 25%

Marek Kowalski PTF, Szczecin Outline  Introduction to Supernova Cosmology  Supernova observations today  A mystery: Dark Energy 3

Marek Kowalski PTF, Szczecin Is Dark Energy a property of the Vacuum? Ground-state of a scalar Quantum-field: Vacuum-Energy density: (with ultraviolet Cut-off k max ) Casimir-Effekt  Energiedifferenz

Marek Kowalski PTF, Szczecin Vakuum energy: Before: E = 0 After: Ax  >0 Pressure (p) of Vacuum energy follows with assumption of energy conservation: Ax  +Axp = 0  p = -   x A Is Dark Energy a property of the Vacuum? Vacuum energy has all the properties of the Cosmological constant , it has negative pressure and hence can lead to acceleration of Universe.

Marek Kowalski PTF, Szczecin Fundamental Problems of Vakuum Energy/Cosmological Constante: Why so small? Expectation:    planck ) 4  120 orders of magntides to larger then the observed value! Why now? Matter:   R -3 Vakuum Energy:   konstant New Physics: Quintessence fields Extra dimensions Modification of Gravity … More data will hopefully tell us!

Marek Kowalski PTF, Szczecin Future projects in SN Cosmology Projekt z-Range # SNe Pan-STARRS ~10 4 LSST (2015) ~10 6 SNAP (2017) >3000 (JDEM/Euclid) SNAP 20

Marek Kowalski PTF, Szczecin Conclusion 3/4 of the energy budget of the Universe consists of Dark Energy It looks like a cosmological constant / vacuum energy - but this interpretation has problems Next generation telescopes will produce unprecedented cosmological observations, and perhaps provide an answer

Ende

Marek Kowalski PTF, Szczecin Back Up

Marek Kowalski PTF, Szczecin Beobachtete Energiedichten Erwartete Energiedichten: Gravitation: SUSY: Electroweak: Fundamentale Probleme mit der Vakuum-Energie/Kosmologischen Konstante:

Marek Kowalski PTF, Szczecin Zustandsgleichung: w =p/  19

Marek Kowalski PTF, Szczecin Zustandsgleichung: w =p/  SNe + BAO + CMB 19 cosmological constant

Marek Kowalski PTF, Szczecin heterogener Datensatz

Marek Kowalski PTF, Szczecin Study of - mean deviation - residual slope A heterogenous data sample

Marek Kowalski PTF, Szczecin Test for Tension high-z low-z mean deviation: OK

Marek Kowalski PTF, Szczecin Test for Tension high-z low-z residual slope: (OK)