tom theuns institute for computational cosmology, durham, uk department of physics, antwerp, belgium...
TRANSCRIPT
Tom TheunsInstitute for Computational Cosmology, Durham, UKDepartment of Physics, Antwerp, Belgium
Groningen 2005
ReionizationReionizationAnd the thermal history of the IGMAnd the thermal history of the IGM
Tom TheunsInstitute for Computational Cosmology, Durham, UKDepartment of Physics, Antwerp, Belgium
Tom Theuns: IGM thermal history
Neutral at z=1000
Ionized at z<6
COBE
Tom Theuns: IGM thermal history
(Perceived?) Tension: zreion=17 (WMAP) or zreion around 6 (quasars)?
Tom Theuns: IGM thermal history
Reionisation by (“first”) stars.
Reed et al. 2005
Tom Theuns: IGM thermal history
Tom Abel
Ciardi et al.
Tom Theuns: IGM thermal history
Tom Theuns: IGM thermal history
When the IGM is highly ionised, the (photo)-heating rate becomes small.
Tom Theuns: IGM thermal history
Tom Theuns: IGM thermal history
2. Numerical simulations: c) photo-ionisation
shocked gas unshocked, photo-ionised gas
Tom Theuns: IGM thermal history
2. Numerical simulations: c) photo-ionisation
Photo-ionisation heating produces a well-defined -T relation in the low-density IGM that produces the Ly-forest. (Hui & Gnedin 1997)
Tom Theuns: IGM thermal history
The IGM temperature affects the widths of the Lyman- lines
TT, Schaye & Haehnelt
Tom Theuns: IGM thermal history
Line-width (b) and temperature are relatedColumn-density (NH) and density are relatedHence can determine -T relation
Schaye et al, Ricotti et al, McDonald et al
Tom Theuns: IGM thermal history
IGM temperature as function of redshift.
Schaye et al.
Tom Theuns: IGM thermal history
Photo-heating rate is less than adiabatic cooling rate
Tom Theuns: IGM thermal history
If no other heat sources, HI reionization late?
Theuns et al.
Tom Theuns: IGM thermal history
Should we not see temperature fluctuations?
Tom Theuns: IGM thermal history
Wavelets are also sensitive to line-widths
Theuns & Zaroubi
Tom Theuns: IGM thermal history
Observed QSO looks similar to simulation with HeII reionisation, but without evidence for T fluctuations.
Theuns et al.Zaldarriaga.
Tom Theuns: IGM thermal history
IGM temperature also affects optical depth (because recombination rate depends on T)
Tom Theuns: IGM thermal history
Sloan DA too noisy to see anything?
Bernardi et al.
Tom Theuns: IGM thermal history
To do list:
better constrain T evolution better constrain fluctuations
other heating sources? (cosmic rays? X-rays? dust?)
Thank you.