Skip to main content

Research Repository

Advanced Search

All Outputs (76)

Suite of hydrodynamical simulations for the Lyman-alpha forest with massive neutrinos (2014)
Journal Article
Rossi, G., Palanque-Delabrouille, N., Borde, A., Viel, M., Yeche, C., Bolton, J. S., …Le Goff, J. (2014). Suite of hydrodynamical simulations for the Lyman-alpha forest with massive neutrinos. Astronomy and Astrophysics, 567, Article A79. https://doi.org/10.1051/0004-6361/201423507

The signature left in quasar spectra by neutral hydrogen in the Universe allows constraining the sum of the neutrino masses with a better sensitivity than laboratory experiments and may shed new light on the neutrino mass hierarchy and the absolute m... Read More about Suite of hydrodynamical simulations for the Lyman-alpha forest with massive neutrinos.

New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations (2014)
Journal Article
Borde, A., Palanque-Delabrouille, N., Rossi, G., Viel, M., Bolton, J. S., Yeche, C., …Le Goff, J. (2014). New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations. Journal of Cosmology and Astroparticle Physics, 2014(July), Article 005. https://doi.org/10.1088/1475-7516/2014/07/005

Current experiments are providing measurements of the flux power spectrum from the Lyman-α forests observed in quasar spectra with unprecedented accuracy. Their interpretation in terms of cosmological constraints requires specific simulations of at l... Read More about New approach for precise computation of Lyman-alpha forest power spectrum with hydrodynamical simulations.

The thermal history of the intergalactic medium down to redshift z=1.5: a new curvature measurement (2014)
Journal Article
Boera, E., Murphy, M. T., Becker, G. D., & Bolton, J. S. (2014). The thermal history of the intergalactic medium down to redshift z=1.5: a new curvature measurement. Monthly Notices of the Royal Astronomical Society, 441(3), https://doi.org/10.1093/mnras/stu660

According to the photoheating model of the intergalactic medium (IGM), He ii reionization is expected to affect its thermal evolution. Evidence for additional energy injection into the IGM has been found at 3 ≲ z ≲ 4, though the evidence for the subs... Read More about The thermal history of the intergalactic medium down to redshift z=1.5: a new curvature measurement.

A consistent determination of the temperature of the intergalactic medium at redshift z=2.4 (2014)
Journal Article
Bolton, J. S., Becker, G. D., Haehnelt, M. G., & Viel, M. (2014). A consistent determination of the temperature of the intergalactic medium at redshift z=2.4. Monthly Notices of the Royal Astronomical Society, 438, https://doi.org/10.1093/mnras/stt2374

We present new measurements of the thermal state of the intergalactic medium (IGM) at z∼2.4 derived from absorption line profiles in the Lyα forest. We use a large set of high-resolution hydrodynamical simulations to calibrate the relationship betwee... Read More about A consistent determination of the temperature of the intergalactic medium at redshift z=2.4.

Probing the metallicity and ionization state of the circumgalactic medium at z~6 and beyond with OI absorption (2013)
Journal Article
Keating, L. C., Haehnelt, M. G., Becker, G. D., & Bolton, J. S. (2013). Probing the metallicity and ionization state of the circumgalactic medium at z~6 and beyond with OI absorption. Monthly Notices of the Royal Astronomical Society, 438(2), https://doi.org/10.1093/mnras/stt2324

Low-ionization metal absorption due to O I has been identified as an important probe of the physical state of the intergalactic/circumgalactic medium at the tail end of reionization. We use here high-resolution hydrodynamic simulations to interpret t... Read More about Probing the metallicity and ionization state of the circumgalactic medium at z~6 and beyond with OI absorption.

The one-dimensional Lyα forest power spectrum from BOSS (2013)
Journal Article
Palanque-Delabrouille, N., Yèche, C., Borde, A., Le Goff, J., Rossi, G., Viel, M., …Weinberg, D. H. (2013). The one-dimensional Lyα forest power spectrum from BOSS. Astronomy and Astrophysics, 559, Article A85. https://doi.org/10.1051/0004-6361/201322130

We have developed two independent methods for measuring the one-dimensional power spectrum of the transmitted flux in the Lyman-α forest. The first method is based on a Fourier transform and the second on a maximum-likelihood estimator. The two metho... Read More about The one-dimensional Lyα forest power spectrum from BOSS.

New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization (2013)
Journal Article
Becker, G. D., & Bolton, J. S. (2013). New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization. Monthly Notices of the Royal Astronomical Society, 436(2), 1023-1039. https://doi.org/10.1093/mnras/stt1610

We present new measurements of the intensity of the ionizing ultraviolet background and the global emissivity of ionizing photons over 2 < z < 5. Our results are based on a suite of updated measurements of physical properties of the high-redshift int... Read More about New measurements of the ionizing ultraviolet background over 2 < z < 5 and implications for hydrogen reionization.

On the rapid demise of Lyman-alpha emitters at z>7 due to the increasing incidence of optically thick absorption systems (2013)
Journal Article
S. Bolton, J., & G. Haehnelt, M. (2013). On the rapid demise of Lyman-alpha emitters at z>7 due to the increasing incidence of optically thick absorption systems. Monthly Notices of the Royal Astronomical Society, 429(2), 1695–1704. https://doi.org/10.1093/mnras/sts455

A variety of independent observational studies have now reported a significant decline in the fraction of Lyman-break galaxies which exhibit Ly-a emission over the redshift interval z=6-7. In combination with the strong damping wing extending redward... Read More about On the rapid demise of Lyman-alpha emitters at z>7 due to the increasing incidence of optically thick absorption systems.

Prospects for detecting the 21 cm forest from the diffuse intergalactic medium with LOFAR (2012)
Journal Article
Ciardi, B., Labropoulos, P., Maselli, A., Thomas, R., Zaroubi, S., Graziani, L., …Yatawatta, S. (2013). Prospects for detecting the 21 cm forest from the diffuse intergalactic medium with LOFAR. Monthly Notices of the Royal Astronomical Society, 428(2), 1755-1765. https://doi.org/10.1093/mnras/sts156

We discuss the feasibility of the detection of the 21 cm forest in the diffuse intergalactic medium (IGM) with the radio telescope LOFAR. The optical depth to the 21 cm line has been derived using simulations of reionization which include detailed ra... Read More about Prospects for detecting the 21 cm forest from the diffuse intergalactic medium with LOFAR.

The intergalactic medium thermal history at redshift z = 1.7–3.2 from the Lyα forest: a comparison of measurements using wavelets and the flux distribution (2012)
Journal Article
Garzilli, A., Bolton, J., -S. Kim, T., Leach, S., & Viel, M. (2012). The intergalactic medium thermal history at redshift z = 1.7–3.2 from the Lyα forest: a comparison of measurements using wavelets and the flux distribution. Monthly Notices of the Royal Astronomical Society, 424(3), 1723-1736. https://doi.org/10.1111/j.1365-2966.2012.21223.x

We investigate the thermal history of the intergalactic medium (IGM) in the redshift interval z = 1.7–3.2 by studying the small-scale fluctuations in the Lyman α forest transmitted flux. We apply a wavelet filtering technique to 18 high-resolution qu... Read More about The intergalactic medium thermal history at redshift z = 1.7–3.2 from the Lyα forest: a comparison of measurements using wavelets and the flux distribution.

The effect of intergalactic helium on hydrogen reionization: implications for the sources of ionizing photons at z>6 (2012)
Journal Article
Ciardi, B., Bolton, J., Maselli, A., & Graziani, L. (2012). The effect of intergalactic helium on hydrogen reionization: implications for the sources of ionizing photons at z>6. Monthly Notices of the Royal Astronomical Society, 423(1), 558-574. https://doi.org/10.1111/j.1365-2966.2012.20902.x

We investigate the effect of primordial helium on hydrogen reionization using a hydrodynamical simulation combined with the cosmological radiative transfer code CRASH. The radiative transfer simulations are performed in a 35.12 h−1 comoving Mpc box u... Read More about The effect of intergalactic helium on hydrogen reionization: implications for the sources of ionizing photons at z>6.

The Lyman α forest flux probability distribution at z>3 (2012)
Journal Article
Calura, F., Tescari, E., D’Odorico, V., Viel, M., Cristiani, S., Kim, T., & Bolton, J. (2012). The Lyman α forest flux probability distribution at z>3. Monthly Notices of the Royal Astronomical Society, 422(4), 3019-3036. https://doi.org/10.1111/j.1365-2966.2012.20811.x

We present a measurement of the Lyman α flux probability distribution function (PDF) obtained from a set of eight high-resolution quasar spectra with emission redshifts in the range 3.3 ≤z≤ 3.8. We carefully study the effect of metal absorption lines... Read More about The Lyman α forest flux probability distribution at z>3.

Improved measurements of the intergalactic medium temperature around quasars: possible evidence for the initial stages of He-II reionisation at z~6 (2012)
Journal Article
S. Bolton, J., D. Becker, G., Raskutti, S., Stuart B. Wyithe, J., G. Haehnelt, M., & L. W. Sargent, W. (2012). Improved measurements of the intergalactic medium temperature around quasars: possible evidence for the initial stages of He-II reionisation at z~6. Monthly Notices of the Royal Astronomical Society, 419(4), 2880–2892. https://doi.org/10.1111/j.1365-2966.2011.19929.x

We present measurements of the intergalactic medium (IGM) temperature within ~5 proper Mpc of seven luminous quasars at z~6. The constraints are obtained from the Doppler widths of Lyman-alpha absorption lines in the quasar near-zones and build upon... Read More about Improved measurements of the intergalactic medium temperature around quasars: possible evidence for the initial stages of He-II reionisation at z~6.

How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641? (2011)
Journal Article
S. Bolton, J., G. Haehnelt, M., J. Warren, S., C. Hewett, P., J. Mortlock, D., P. Venemans, B., …Simpson, C. (2011). How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641?. Monthly Notices of the Royal Astronomical Society: Letters, 416(1), L70–L74. https://doi.org/10.1111/j.1745-3933.2011.01100.x

The quasar ULAS J1120+0641 at redshift z=7.085 has a highly ionised near zone which is smaller than those around quasars of similar luminosity at z~6. The spectrum also exhibits evidence for a damping wing extending redward of the systemic Lya redshi... Read More about How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641?.

The impact of spatial fluctuations in the ultra-violet background on intergalactic carbon and silicon (2011)
Journal Article
S. Bolton, J., & Viel, M. (2011). The impact of spatial fluctuations in the ultra-violet background on intergalactic carbon and silicon. Monthly Notices of the Royal Astronomical Society, 414(1), 241–252. https://doi.org/10.1111/j.1365-2966.2011.18384.x

Spatial inhomogeneities in the spectral shape of the ultra-violet background (UVB) at the tail-end of HeII reionisation are thought to be the primary cause of the large fluctuations observed in the HeII to HI Ly-a forest optical depth ratio, tau_HeII... Read More about The impact of spatial fluctuations in the ultra-violet background on intergalactic carbon and silicon.