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2002MNRAS.335..555K - Mon. Not. R. Astron. Soc., 335, 555-573 (2002/September-3)
The physical properties of the Lyα forest at z > 1.5 .
KIM T.-S., CARSWELL R.F., CRISTIANI S., D'ODORICO S. and GIALLONGO E.
Abstract (from CDS):
For a given N_H I_range, the Lyα forest at 1.5 < z < 4 shows the monotonic evolution, which is governed mainly by the Hubble expansion at this redshift range. In general, the Lyα forest line number density (dn/d z) is best approximated with dn/d z = 6.1(1 + z) ^2.47 ±0.18^ for the HI column density N_H I_= 10 13.64–17 cm –2 at 1.5 < z < 4. When the results at 0 < z < 1.5 from Hubble Space Telescope ( HST ) observations are combined, the slow-down in the number density evolution occurs at z < 1.5. For higher column density clouds at N_H i_> 10 14 cm –2, there is a variation in the line number density from sightline to sightline at z < 2.5. This variation is stronger for higher column density systems, probably due to more gravitationally evolved structures at lower z. The mean H i opacity {formmu17} is {formmu18} at 1.5 < z < 4. HST observations show evidence for slower evolution of {formmu20} at z < 1. For N_H i_= 10 12.5–15 cm –2, the differential column density distribution function, f ( N_H i_), can be best fitted by f ( N_H I_∝ N_H i_–β with β~ 1.5 for 1.5 < z < 4. When combined with HST observations, the exponent β increases as z decreases at 0 < z < 4 for N_H i_= 10 13–17 cm –2. The correlation strength of the step optical depth correlation function shows the strong evolution from <z >= 3.3 to <z >= 2.1, although there is a large scatter along different sightlines. The analyses of the Lyβ forest at z ∼ 2.2 are, in general, in good agreement with those of the Lyα forest.
Abstract Copyright: RAS
Journal keyword(s): quasars: absorption lines.
VizieR on-line data: <Available at CDS (J/MNRAS/335/555): table1.dat q0055.dat q0302.dat q1101.dat q1122.dat q1347.dat>
Simbad objects: 35
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