Frontiers of Cosmology (eBook)

Contents 6
Preface 10
1 Basics of Cosmology 12
Introduction 12
1. Geometry and Dynamics Geometry of 4-dimensional space-time 13
2. Important quantities needed for observations 16
3. Some solutions of EFL equations:some cosmological models 19
4. The standard Big Bang Nucleosynthesis (SBBN) 23
5. Observations of “primordial abundances”. 27
6. Confrontation of the observed “primordial abundances” to the predictions of the sBBN. 29
7. Conclusions 31
References 32
2 The X-ray View of Galaxy Clusters 34
Introduction 34
Unique X-ray Cluster Properties 35
1. Observing Clusters in X-rays – the Chandra Observatory 38
Detectors 39
Cluster Morphologies 39
Cluster Formation 41
2. Regular Clusters XD Cooling Flows 44
Gas and Galaxies in Equilibrium in a Cluster 44
Mass distribution 45
Applications to galaxy clusters 46
3. Physics of Cluster Cores 47
Acknowledgments 52
References 52
3 Clusters: an optical point of view 54
Introduction 54
1. Cluster detections in the optical 55
Adaptative filters 55
Red sequence 56
Blind spectroscopic surveys 57
Detections using photometric redshifts 57
2. Studies of clusters 58
Dynamical aspects 58
Photometric aspects 60
3. Acknowledgements 65
References 65
4 Cosmology with Clusters of Galaxies 68
1. Introduction 68
2. What is a cluster? 69
3. The spherical model 70
4. The mass function 70
5. Connection to the observations 71
6. Properties of Clusters and scaling relations 74
X-ray properties 74
Scaling relations 75
7. Clusters abundance evolution. 76
The local temperature distribution function 76
Application to the determination of 78
8. The baryon fraction 79
9. Conclusion 83
References 83
5 Astrophysical detection of Dark Matter 86
1. Signals from the Dark universe 86
2. Inference probes 87
3. Physical probes 88
4. Conclusion 94
References 94
6 Non-thermal and relativistic processes in galaxy clusters 96
Introduction 96
1. Non-thermal and relativistic phenomena in galaxy clusters 97
2. The origin of cosmic rays in galaxy clusters 101
3. The astrophysics of cosmic rays in galaxy clusters 105
4. Conclusions 109
References 109
7 An introductory overview about Cosmological Inflation 112
1. Introduction 112
2. The hot Big-Bang scenario and its problems 114
Definitions and expansion dynamics 114
Horizon problem 117
Flatness problem 118
Unwanted relic problem 118
Structure formation problem 120
3. Inflation and infiationary dynamics 120
Scalar field 120
Slow-roll conditions 124
An example: chaotic inflation 126
When does inflation end? 127
4. Basics of cosmological perturbations 128
Gauge issues 129
Fixing the coordinate system 131
Scalar-vector-tensor decomposition 132
Some gauges 135
Gauge invariant matter perturbations 136
Einstein and conservation equations 138
5. Infiationary perturbations 139
Perturbed scalar field 139
Large scale solution 141
6. Basics of quantum field theory 143
7. Perturbation spectrum 145
8. Conclusion 148
References 148
8 An introduction to quintessence 150
Introduction 150
1. The two cosmological constant problems 150
2. A scalar field as dark energy 152
3. Stability of the wQ = Const regime 153
4. Model building 154
5. Dark energy and structure formation 156
6. Observational status 156
References 158
9 CMB Observational Techniques and Recent Results 160
1. Introduction 161
2. Observational Techniques 165
Chopping 166
Scanning 170
Frequency Range 173
Sensitivity 173
3. Recent Observations 178
DASIPOL 178
ARCHEOPS 178
ACBAR 178
4. Summary 181
Acknowledgments 182
References 182
10 Fluctuations in the CMB 186
1. Introduction 186
2. Cosmological Preliminaries 187
3. The Last Scattering Surface 189
Reionization 190
4. Perturbations on Large and Small Scales 191
5. Oscillations in the Primordial Plasma 194
Large Scales: The Sachs-Wolfe effect 196
Small scales: Acoustic oscillations 197
6. The Power Spectrum of CMB Fluctuations 198
7. The CMB and Cosmological Parameters 199
8. Conclusions 202
Acknowledgments 203
References 204
11 Supernovae as astrophysical objects 206
1. Some History 206
2. Supernova classi.cation 207
3. Input Energy 210
4. Core-collapse supernovae 211
5. Type Ia supernovae 213
6. Conclusions 213
References 214
12 Cosmology with Supernovae 218
1. Introduction 218
2. The Hubble constant 219
Type Ia supernovae 219
Core-collapse supernovae 221
3. The expansion history of the universe 221
4. Universal acceleration according to Type Ia supernovae 222
5. Characterising dark energy 225
6. Conclusions 226
References 227
13 Gravitational lensing: from µ-lensing to cosmic shear experiments 230
1. Introduction 230
2. Physical mechanisms 231
Born approximation and thin lens approximation 232
The induced displacement 232
The case of a point-like mass distribution 232
3. Gravitational lenses in Cosmology 235
Cosmological distances and gravitational potential 235
Galaxy clusters as gravitational lenses 236
The isothermal pro.le 237
The weak lensing regime 240
4. Cosmic Shear: weak lensing as a probe of the large- scale structure 241
5. Conclusions and perspectives: cosmic shear in a precision cosmology era 250
References 250
14 Dark Matter: Early Considerations 252
1. Introduction 252
2. Local Dark Matter 253
3. Clusters and Groups of Galaxies 254
4. Masses of Galaxies 256
Galactic Models 256
Mass-to-luminosity Ratios and Models of Physical Evolution of Stellar Populations 257
Mass Discrepancy on the Periphery of Galaxies 258
Galactic Coronas 259
Dark Matter Conferences 1975 260
Are Pairs of Galaxies Physical? 261
Additional Evidence for Dark Halos 263
5. The Nature of Dark Matter 263
Neutrino-dominated Universe 263
Dark Matter and the Structure of the Universe 264
Cold Dark Matter 266
The amount of dark matter 267
6. Summary 267
Acknowledgments 269
References 269
15 Dark Matter and Galaxy Formation 274
1. Challenges of dark matter 274
2. Global baryon inventory 275
3. Confirmation via detailed census of MWG/M31 276
4. Hierarchical galaxy formation 277
5. Unresolved issues in galaxy formation theory 279
6. Resurrecting CDM 280
7. An astrophysical solution: early winds 282
8. Observing CDM via the WIMP LSP 284
9. The future 285
References 288
16 Non-Baryonic Dark Matter 290
1. The need for non-baryonic dark matter 290
2. Popular candidates for non-baryonic dark matter 292
Type Ia: candidates that exist 293
Type Ib: ‘well-motivated’ candidates 296
Type II: other candidates 306
3. Neutralino dark matter searches 310
Direct detection 310
Indirect detection 320
4. Conclusions 337
References 338

3. Input Energy (p. 199-200)

It is interesting to evaluate the energy sources of the two explosion mechanisms. Gravity is the drive behind the core-collapse supernovae. The collapse of about 1.5 M to nuclear densities or beyond release about 1053 erg. Most of this energy is radiated in anti-neutrinos, which escape in the formation of neutrons out of protons and electrons. About 1051 erg go into kinetic energy pushing the envelope away and only 1049 erg go into electromagnetic radiation signalling the death of the star across the universe. The thermonuclear explosions draw their energy from the energy difference of the binding energy of oxygen and carbon compared to the iron-peak elements. About one solar mass of O and C are burned and an energy of 1049 erg is released in electro-magnetic radiation.

There are several effects that can in.uence the electro-magnetic display of supernovae. Shocks further convert kinetic energy into radiation. Some of the radiation can not escape the dense explosion and only when the debris expand and adiabatically cool is some of it released. Energy that went into ionising the envelope is released when the material cools down enough so that the atoms recombine again. For supernovae with extended envelope this recombination can create an extended plateau phase in the light curve, where the expansion of the atmosphere is balanced by the inward moving wave of recombination.

One of the best observed examples is SN 1999em Hamuy et al. 2001, Elmhamdi et al. 2003 where the plateau lasted for about 100 days. However, the largest energy reservoir is stored in radioactive isotopes that release ?-rays after typical decay times. The most important channel is the ?-decay of 56Ni into 56Co and then stable 56Fe (e.g. Diehl &, Timmes 1998. For the core-collapse supernovae this channel provides the energy input for the late light curves (after the plateau phase), while it is the only energy input for SNe Ia Leibundgut &, Suntzeff 2003. Bolometric light curves can be used to track the change in escape fraction of the ?-rays from the supernova ejecta Leibundgut. &, Pinto 1992, Contardo et al. 2000.

For massive supernovae the absolute luminosity after about 120 days, together with the age of the supernova, gives a relatively accurate measure of the amount of 56Co synthesised in the explosion Hamuy et al. 2003B, Elmhamdi et al. 2003. This measurement is now available for many core-collapse supernovae and is typically a factor 10 less than assumed in thermonuclear supernovae but spans almost a factor of 100 Pastorello et al. 2004. The long and rich light curve observed for SN 1987A is a clear demonstration of how the various physical effects form the light curve Leibundgut &, Suntzeff 2003. It shows many of the described features and some more.

Hypernovae have been added to the list of supernovae and they represent the high energy end (at least in their kinematics) with the high velocities observed in these objects. The connection of gamma–ray burst with supernovae has now been generally accepted with the observations of SN 2003dh/GRB030329 (e.g. Stanek et al. 2003, Matheson et al. 2003, Hjorth. et al. 2003. It should be noted that already SN 1998bw/GRB980425 showed all the signatures of a supernova Galama et al. 1998, Patat et al. 2001.