Cosmology with supernovae Using SNIa lightcurves to infer cosmological parametersRui Pereira
CENTRA - IST
Lisboa - Portugal
Cosmology with supernovae Using SNIa lightcurves to infer cosmological parameters
Rui Pereira
CENTRA - IST
Lisboa - Portugal
Meter foto de supernova
The standard model of cosmology
Friedmann equation scale factor curvature cosmological constant total energy density Cosmological Principle – homogeneous and isotropic universe
Einstein equation
Friedmann Lemâitre Robertson Walker model
Chamar atencao vacuo
The expanding universe
Every galaxy at distance d is moving away with velocity v given by the Hubble law
Critical density of the universe
Ver o V
Ver rho crit
Densidade 3 atomos numa sala
Atencao equacao
Tirar ultima equacao
The expanding universe
Ωtot > 1
Closed universe Ωtot = 1
Flat universe Ωtot < 1
Open universe The overall geometry of the universe is determined by Ωtot
N falar
The cosmological parameters
Assuming that the ρrad contribution can be neglected
We can rewrite the Friedmann equation
+rho rad com fade
Distances and parameters determination
How to obtain informations on the cosmological parameters?
Standard candles – sources of known intrinsic luminosity as a function of redshift
Acrescentar equacao de f=l/4pidL
Standard candles
Luminosity distance
apparent luminosity luminosity distance redshift scale factor Flux detected at the telescope
Distances and parameters determination
absolute magnitude luminosity distance cosmological parameters dependence! apparent magnitude General solution
Mag num slide à parte
Distances and parameters determination
Luminosity distance vs. redshift
Measuring apparent magnitudes of standard candles we can solve for the cosmological parameters – the contents of the universe!
Supernovae
Explosion and death of a star
Characteristics depend on progenitor’s mass, radius, chemical composition and stage of stellar evolution
Type I (no H line)
Ia: presence SiII lines
Ib: presence He absence SiII
Ic: He and SiII absence
Type II (H line)
Tirar stellar evolution
Muito pouco H – haveria muito pouco na fase inicial
Type Ia supernovae
White dwarf accreting mass from companion
Approaches Chandrasekhar mass limit
Por maradona
10^51 ergs
Potencia de varios sois durante toda a sua vida
Type Ia supernovae White dwarf accreting mass from companion
Approaches Chandrasekhar mass limit Bright and homogeneous enough to be used as cosmological distance indicators
Lightcurve analysis shows an empirical relation between lightcurve width and maximum luminosity
Brighter supernovae decline more slowly than fainter ones
What to do then?
Standardization
Empirical methods have been developed to correct the observed dispersion
SCP slide com todas juntinhas
Results
Supernova Cosmology Project
ApJ, 517, 565 With accurate photometry, calibrated SNIa are very attractive as distance indicators for cosmology
Falar High-z
Fazer referencia a APJ
Not sleeping yet?
Great!
Now for the fun part :)
A nearby supernovae campaign
Better understanding of intrinsic SNIa properties is of primary importance
empirical lightcurve width-luminosity relation
luminosity peak dispersion
extintion by abnormal galactic dust
Large set of well calibrated lightcurves from nearby SN
used to create superior SN lightcurve templates
further applied to high-z SN
Data aquisition
Intermediate Redshift Supernova Search
La Palma – mid 2002
About 10 new SNIa discovered at Isaac Newton Telescope, with followup made on other 3 telescopes
Copy the following code to your webpage or blog to embed this presentation:
<a href="http://www.slidefinder.net/c/cosmology_supernovae_using_snia_lightcurves/cosmologywithsupernovae/21465855" class="slidefinder">Cosmology with supernovae</a>
Comments