Cosmology ETs komplett

What are the most basic processes of galaxy formation?

Are decaying modes relevant for structure formation? What about growing modes?

Consider the density contrast, δ, as a superposition of plane waves, how do density perturbations lead to halos and voids, respectively.

What are fundamental assumptions of standard cosmological models? (Mark all correct answers)

What is the motivation for/advantage of using comoving coordinates?

What new parameters are introduced in the Robertson-Walker metric to describe the dynamics of the Universe?

Which are sensible interpretations of cosmological redshift? (mark all correct answers)

What are the main steps involved in deriving the Friedmann equations?

What forms of matter are useful to distinguish when considering their effect on the expansion of the Universe? And what are their properties?

How can the Hubble parameter be characterised?

What is the critical density of the Universe and how is it related to its expansion rate?

How does a positive cosmological constant Lambda affect the expansion of the Universe?

Why does the Universe have radiation- and matter-dominated eras?

How can the matter power spectrum be sensibly described?

What is the meaning of the real space correlation function ξ ( y )? How is it tied to the definition of P(k)?

What is the exact meaning of the parameter \sigma_8, which is a measure for the amount of density fluctuations?

Why is the matter power spectrum, P(k), rising with increasing k at low k and falling off at higher k?

 What is the basic idea behind the Zel'dovich approximation?

During linear evolution, do wave modes of different wave number influence each other? How does non-linear evolution modify the matter power spectrum?

Describe the qualitative behavior of non-linear structure formation (in position space).

 What do we mean by hierarchical structure formation of cold dark matter?

To what extend to galaxy rotation curves provide evidence for dark matter?

How is the X-ray emission of galaxy clusters produced?

What is a galaxy cluster composed of?

How does the bullet cluster provide evidence for dark matter?

From cosmic microwave background observations, why must dark matter be non-baryonic?

What does a NFW profile describe and what are its properties?

What is the difference between the Hubble velocity and the peculiar velocity?

What is the basic idea of studying structure formation with linear perturbation theory?

What is the limit of applicability of the linear perturbation equations as laid down in Eq. (2.17)?

How does the evolution of a perturbation depend on the Jeans length?

What is the requirement for maintaining thermal equilibrium in an expanding Universe?

How does the temperature of the cosmic microwave background (CMB) and the intergalactic medium (IGM) decrease during adiabatic expansion of the Universe?

Is it easier to maintain thermal equilibrium between particles in the early or late Universe and why?

What do cosmologists mean when they refer to the freeze-out of a specific particle species?

Do particles retain their thermal equilibrium density after freeze-out?

What process does recombination refer to in cosmology?

The binding energy of hydrogen E_H = 13.6 eV corresponds to a temperature of T_H = E_H/kB = 1.5e5 K, where kB is the Boltzmann constant. When this is so, why does recombination take place at T ∼ 3000 K rather than at T_H?

The significant duration of recombination led to the release of CMB photons at different redshifts. Is this visible in our measurements of the CMB spectrum, and why or why not?

What process is described by the term (Big Bang) nucleosynthesis?

How can relative element abundances be used to constrain the density of ordinary matter in the Universe?

Select all correct statements about the standard cosmological parameters? (Multiple answers can be correct)

What are reasonable approximate values of the cosmological parameters?

What is the definition and meaning of the Hubble time?

Which statements about cosmological distance measures are correct? (Multiple answers can be correct)

Which are effects that contribute to the difference between luminosity and angular diameter distance?

How does the scale factor depend on time t in different epochs?

What do the redshift dependences of the luminosity and angular diameter distance imply for galaxies at z>2? Assume their physical size and emission is constant across the redshifts considered.

What is the difference between Hubble radius, particle horizon and event horizon?

How can supernova be used to constrain the expansion history of the Universe?

What is the equation of state of dark energy and what values does it need to have to drive an accelerated expansion of the Universe (d^2a/dt^2>0) in the limit in which it dominates the energy density?

What is flatness problem in cosmology?

Why can perturbations lose causal contact during inflation?

Why is there a dipole pattern present in the CMB temperature across the sky?

What is the Sachs-Wolfe effect?

How does the amount of baryons in the baryon-photon fluid affect its properties?

How does the mean free path of photons affect the CMB?

Why is the CMB somewhat polarized?

What set of basis functions is used for studying the statistical properties of the CMB and its power spectrum?

What do cosmologists expect to happen in the very early universe within a Planck time after the Big Bang?

What is the horizon problem in cosmology?

In the prevailing picture of galaxy formation, what feedback channels dominate the regulation of star formation in low- and high-mass halos?

How does cosmic reionization affect the baryon content of halos of different size?

What is meant by "wind mass loading factor" when talking about galactic winds?

What is the Lyman-alpha forest?

What is the typical energy injected by a supernova (SN)? And how many SN are expected per total stellar mass formed?

What are the phases of a supernova explosion propagating into the ISM in the order in which they happen?

What is the Eddington limit/luminosity?

How much energy is required to inflate an AGN bubble (and fill it with relativistic particles) to volume V into a surrounding ICM with pressure P?

What fraction of the baryonic mass is typically converted to stars in L_* galaxies? Is this fraction larger or small in halos of smaller and larger mass?