A thermal history

Universe: Thermal History

Week 3: Thermal History of the Universe

• T ∼ 10−4 eV, t ∼ 1010 yr: today; baryons and the CMB are entirely decoupled, stars and galaxies have been around a long time, and clusters of galaxies (gravitationally bound systems of ∼ 1000s of galaxies) are becoming common. • T ∼ 10−3 eV, t ∼ 109 yr; the first stars and (small) galaxies begin to form. • T ∼ 10−1−2 eV, t ∼ millions of years: baryon drag ends; at earlier times, the baryons a...

The thermal history of the intergalactic medium

At redshifts z2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyα forest. This photoheated gas follows a tight temperature-density relation which introduces a cut-off in the distribution of widths of the Lyα absorption lines (b-parameters) as a function of column density. We have measured this cut-off in a sample of nine high reso...

History of the Baths and Thermal Medicine

1 University G. Marconi of Rome, Dermatology and Venereology, Rome 00192, Italy; 2 Medical Institute of the Ministry of Interior, Dermatology, Venereology and Dermatologic Surgery; Onkoderma, Private Clinic for Dermatologic Surgery, Dermatology and Surgery, Sofia 1407, Bulgaria; 3 Krankenhaus Dresden-Friedrichstadt, Department of Dermatology and Venereology, Dresden, Sachsen, Germany; 4 Univers...

The Thermal Memory of Reionization History

The recent measurement by WMAP of a large electron scattering optical depth τe = 0.17 ± 0.04 is consistent with a simple model of reionization in which the intergalactic medium (IGM) is ionized at redshift z ∼ 15, and remains highly ionized thereafter. Here, we show that existing measurements of the IGM temperature from the Lyman-alpha (Lyα) forest at z ∼ 2 − 4 rule out this “vanilla” model. Un...