Cosmology particle astrophysics fk7007 observational cosmology
This presentation is the property of its rightful owner.
Sponsored Links
1 / 37

Cosmology & Particle Astrophysics, FK7007 Observational Cosmology PowerPoint PPT Presentation


  • 164 Views
  • Uploaded on
  • Presentation posted in: General

Cosmology & Particle Astrophysics, FK7007 Observational Cosmology. Observational Cosmology. Ariel Goobar. Part I: THE EXPANSION. Birth of observational cosmology (1929) Edwin Hubble ’ s discovery: Universe expands!. Hubble law :. Hubble law. Hubble parameter.

Download Presentation

Cosmology & Particle Astrophysics, FK7007 Observational Cosmology

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Cosmology & Particle Astrophysics, FK7007Observational Cosmology

Observational Cosmology

Ariel Goobar


Part I: THE EXPANSION


Birth of observational cosmology (1929) Edwin Hubble’s discovery: Universe expands!

Hubble law:


Hubble law


Hubble parameter

= time derivative of universal scale factor


Pioneering work: redshift of nebulae VestoSlipher (1875- 1969)


Pioneering work: redshift of nebulae VestoSlipher (1875- 1969)


Pioneering work: redshift of nebulae VestoSlipher (1875- 1969)

1917: evidence for expansion existed already in this data, but there was no theoretical prediction suggesting that at the time…


Estimates of H0 from Type Ia Supernovae: accuratedistances!

Credits: Saurabh Jha


Type Ia supernovae as standard candles: bright homogeneous objects, excellent for distance estimates


Supernova classification

Best ”standard candles” we know today


Fig. Dan Kasen


What systems could lead to SNeIa?

Single degenerate

Double degenerate

CSM more likely in SD scenario


Nearly a standard candle


Luminosity Distance

  • where F(x) = sin(x) for a closed universe, sinh(x) for an open universe and x for a flat universe. In the latter case the ΩKterms are set to 1.


Cosmological parameters

“dark energy”


The Nobel Prize in Physics 2011

Saul Perlmutter, The Supernova Cosmology Project

Brian P. Schmidt and Adam G. Riess, The High-z Supernova Search Team

"for the discovery of the accelerating expansion of the Universe

through observations of distant supernovae”


1998: Cosmological constant not zero!

18


SCP & HZT – December 2011


Cosmology fits

Search

Lightcurve

Hubble diagram

Reference

SN-cosmology tutorial


Perlmutter et al 1994

Two decades of hard work!

SN1992bi

z=0.458

z=0.998

Goobar & Leibundgut,

Annual Review of Nuclear and Particle Science 61 (2011) 251-279

Guy et al 2010


1995


Redshift range

AG & Perlmutter 95


Wide lever arm in redshift is key!

AG & Perlmutter 95


State of the art

14

9

6

5

4

Gyrs since

Big Bang

Rodney et al 2012

Rubin et al 2013 (SCP)

Suzuki et al

2012 (SCP)

Union2.1 data-set + 2 = 582 SNe


State of the art

14

9

6

5

4

Gyrs since

Big Bang

Hubble

Space

Telescope

Rodney et al 2012

Rubin et al 2013 (SCP)

Suzuki et al

2012 (SCP)

Union2.1 data-set + 2 = 582 SNe


(nm)


(nm)


Mainly from space.

Field of view of Hubble Space Telescope

~100x smaller than available for optical ground based surveys.

(nm)


Is it really Einstein’s Λ?Dark Energy EoS, w=p/ρ

  • Λ-hypothesis (w=-1) unchallenged by observations

  • Theoretical understanding still lacking

  • Expected vacuum energy density, ρvac, has w=-1,but >1056 times off!

Amanullah et al 2010


Fitting distances from SNIa with SALT

β~2.5 (Amanullah et al.

2010): very unusual reddening coefficient

Brightness (rest-frame Bmax) and

color (c~E(B-V)) at maximum

Measured variables

Fitted parameters

Fitted peak brightness

can be color and

light-curve shape

corrected to form a

standard candle that

can be used for

measuring relative

cosmological distances.

Shape (x1)

Normalised flux

Days since maximum (rest-frame)


Current & Proposed SNIa Surveys

Optical

Near-IR

LSST (2020?): 8-m/9 sq.deg

250000/yr

DES (2012-2016): 4-m/3 sq.deg

EUCLID (2020?):1.2 m/0.5 sq.deg

Amanullah et al

2010

Fig. from Hook et al


Stage IV forecast (SN+WL+BAO)

Amanullah et al

Union 2

w = w0 + (1-a)wa

Fig. adapted by

Joel Johansson


Easy!


Harder!


w = w0 + (1-a)wa

Really, really hard!

37


  • Login