2010ApJ...718..199L


Query : 2010ApJ...718..199L

2010ApJ...718..199L - Astrophys. J., 718, 199-230 (2010/July-3)

A measurement of small-scale structure in the 2.2 ≤ z ≤ 4.2 Lyα forest.

LIDZ A., FAUCHER-GIGUERE C.-A., DALL'AGLIO A., McQUINN M., FECHNER C., ZALDARRIAGA M., HERNQUIST L. and DUTTA S.

Abstract (from CDS):

The amplitude of fluctuations in the Lyα forest on small spatial scales is sensitive to the temperature of the intergalactic medium (IGM) and its spatial fluctuations. The temperature of the IGM and its spatial variations contain important information about hydrogen and helium reionization. We present a new measurement of the small-scale structure in the Lyα forest from 40 high resolution, high signal-to-noise ratio, VLT spectra for absorbing gas at redshifts between 2.2 ≤ z ≤ 4.2. We convolve each Lyα forest spectrum with a suitably chosen Morlet wavelet filter, which allows us to extract the amount of small-scale structure in the forest as a function of position across each spectrum. We monitor contamination from metal line absorbers. We present a first comparison of these measurements with high-resolution hydrodynamic simulations of the Lyα forest that track more than 2 billion particles. This comparison suggests that the IGM temperature close to the cosmic mean density (T0) peaks at a redshift near z = 3.4, at which point it is greater than 20, 000 K at ≳2σ confidence. The temperature at lower redshift is consistent with the fall-off expected from adiabatic cooling (T0{vprop} (1 + z)2), after the peak temperature is reached near z = 3.4. In our highest redshift bin, centered around z = 4.2, the results favor a temperature of T0= 15-20, 000 K. However, owing mostly to uncertainties in the mean transmitted flux at this redshift, a cooler IGM model with T0= 10, 000 K is only disfavored at the 2σ level here, although such cool IGM models are strongly discrepant with the z ≈ 3-3.4 measurement. We do not detect large spatial fluctuations in the IGM temperature at any redshift covered by our data set. The simplest interpretation of our measurements is that He II reionization completes sometime near z ≈ 3.4, although statistical uncertainties are still large. Our method can be fruitfully combined with future He II Lyα forest measurements.

Abstract Copyright:

Journal keyword(s): cosmology: theory - intergalactic medium - large-scale structure of universe

Simbad objects: 6

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Number of rows : 6
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 QSO B0940-1050 QSO 09 42 53.5076745009 -11 04 25.929146122   16.96 16.6 16.6   ~ 89 0
2 QSO B1158-1842 QSO 12 00 44.9453271433 -18 59 44.478488620   17.22 16.93     ~ 56 0
3 QSO B1202-074 QSO 12 05 23.12 -07 42 32.4     17.5     ~ 355 5
4 LBQS 2139-4434 QSO 21 42 25.7847067944 -44 20 18.353629202   18.83 16.64     ~ 44 0
5 QSO J2246-6015 QSO 22 47 08.9261267635 -60 15 45.301367673           ~ 63 0
6 QSO B2347-4342 QSO 23 50 34.2595236845 -43 25 59.680334378   16.3 16.3     ~ 161 0

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2021.08.04-13:27:11

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