Reionization Signatures in Quasar Absorption Spectra: Exploring the Dark Ages of the Universe - Softcover

Gallerani, Simona

Softcover

ISBN 10: 3843394296 ISBN 13: 9783843394291

Publisher: LAP LAMBERT Academic Publishing, 2011

Synopsis

Moving backwards in time, the first observable of the Universe is the Cosmic Microwave Background, signature of the recombination process occurred at z~1100. Limited by the sensitivity of current telescopes, we are now able to detect objects up to z~8. Nowadays, we are thus dealing with a lack of observational data in the range 8>z>1100, cosmic epochs called “Dark Ages”. After the recombination process, the Universe is almost completely homogeneous and neutral. Gravitational instability allows tiny fluctuations in the primordial density field to grow in the pre- existing dark matter halo potential wells, and eventually to form the first bound objects. It is only at z∼20-30 that the gas is finally able to cool and form the first stars. The photons from the first luminous sources ionized the surrounding neutral medium. Once individual ionized regions started overlapping the global ionization and thermal state of the intergalactic medium changed drastically. The process which marks the transition from an almost completely homogeneous and neutral Universe to the highly structured and ionized one that we presently observe is called “cosmic reionization”.

About this title

About the Author

Simona Gallerani was born in Bari, a sunny city on the southernItalian coast. Here, she started her studies in Physics, then completed at theUniversity of Padova. Afterwards, she moved to Trieste where she got her PhilosophiaeDoctor in Astrophysics at the International School for Advanced Studies.

Edition details

• Publisher: LAP LAMBERT Academic Publishing
• Publication date: 2011
• ISBN 10: 3843394296
• ISBN 13: 9783843394291
• Binding: Paperback
• Language: English
• Number of pages: 164