Cosmology particle astrophysics fk7007 observational cosmology
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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.

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Cosmology particle astrophysics fk7007 observational cosmology

Cosmology & Particle Astrophysics, FK7007Observational Cosmology

Observational Cosmology

Ariel Goobar


Part i the expansion

Part I: THE EXPANSION


Birth of observational cosmology 1929 edwin hubble s discovery universe expands

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

Hubble law:


Hubble law

Hubble law


Cosmology particle astrophysics fk7007 observational cosmology

Hubble parameter

= time derivative of universal scale factor


Pioneering work redshift of nebulae vesto slipher 1875 1969

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


Pioneering work redshift of nebulae vesto slipher 1875 19691

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


Pioneering work redshift of nebulae vesto slipher 1875 19692

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 h 0 from type ia supernovae accurate distances

Estimates of H0 from Type Ia Supernovae: accuratedistances!

Credits: Saurabh Jha


Type ia supernovae as standard candles bright homogeneous objects excellent for distance estimates

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


Supernova classification

Supernova classification

Best ”standard candles” we know today


Cosmology particle astrophysics fk7007 observational cosmology

Fig. Dan Kasen


What systems could lead to sneia

What systems could lead to SNeIa?

Single degenerate

Double degenerate

CSM more likely in SD scenario


Nearly a standard candle

Nearly a standard candle


Luminosity distance

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

Cosmological parameters

“dark energy”


Cosmology particle astrophysics fk7007 observational cosmology

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

1998: Cosmological constant not zero!

18


Scp hzt december 2011

SCP & HZT – December 2011


Sn cosmology tutorial

Cosmology fits

Search

Lightcurve

Hubble diagram

Reference

SN-cosmology tutorial


Two decades of hard work

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


Cosmology particle astrophysics fk7007 observational cosmology

1995


Redshift range

Redshift range

AG & Perlmutter 95


Wide lever arm in redshift is key

Wide lever arm in redshift is key!

AG & Perlmutter 95


State of the art

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 art1

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


Cosmology particle astrophysics fk7007 observational cosmology

(nm)


Cosmology particle astrophysics fk7007 observational cosmology

(nm)


Cosmology particle astrophysics fk7007 observational cosmology

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 dark energy eos w p

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

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

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

Stage IV forecast (SN+WL+BAO)

Amanullah et al

Union 2

w = w0 + (1-a)wa

Fig. adapted by

Joel Johansson


Cosmology particle astrophysics fk7007 observational cosmology

Easy!


Cosmology particle astrophysics fk7007 observational cosmology

Harder!


Cosmology particle astrophysics fk7007 observational cosmology

w = w0 + (1-a)wa

Really, really hard!

37


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