Research Repository

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A new measurement of the intergalactic temperature at z∼2.55 − 2.95 (2017)
Journal Article
Rorai, A., Carswell, R., Haehnelt, M. G., Becker, G. D., Bolton, J. S., & Murphy, M. T. (2017). A new measurement of the intergalactic temperature at z∼2.55 − 2.95. Monthly Notices of the Royal Astronomical Society, 474(3), doi:10.1093/mnras/stx2862. ISSN 0035-8711

We present two measurements of the temperature-density relationship (TDR) of the intergalactic medium (IGM) in the redshift range 2.55 < z < 2.95 using a sample of 13 high-quality quasar spectra and high resolution numerical simulations of the IGM. O... Read More

First constraints on fuzzy dark matter from Lyman-alpha forest data and hydrodynamical simulations (2017)
Journal Article
Irsic, V., Viel, M., Haehnelt, M. G., Bolton, J. S., & Becker, G. D. (2017). First constraints on fuzzy dark matter from Lyman-alpha forest data and hydrodynamical simulations. Physical Review Letters, 119(3), doi:10.1103/PhysRevLett.119.031302. ISSN 0031-9007

We present constraints on the masses of extremely light bosons dubbed fuzzy dark matter from Lyman- α forest data. Extremely light bosons with a De Broglie wavelength of ~ 1 kpc have been suggested as dark matter candidates that may resolve some of t... Read More

New constraints on the free-streaming of warm dark matter from intermediate and small scale Lyman-alpha forest data (2017)
Journal Article
Irsic, V., Viel, M., Haehnelt, M. G., Bolton, J. S., Cristiani, S., Becker, G. D., …Worseck, G. (2017). New constraints on the free-streaming of warm dark matter from intermediate and small scale Lyman-alpha forest data. Physical Review D, 96, doi:10.1103/PhysRevD.96.023522. ISSN 2470-0010

We present new measurements of the free-streaming of warm dark matter (WDM) from Lyman-α flux-power spectra. We use data from the medium resolution, intermediate redshift XQ-100 sample observed with the X-shooter spectrograph (z = 3 – 4.2) and the hi... Read More

The effect of stellar and AGN feedback on the low redshift Lyman-α forest in the Sherwood simulation suite (2017)
Journal Article
Nasir, F., Bolton, J. S., Viel, M., & Kim, T. (2017). The effect of stellar and AGN feedback on the low redshift Lyman-α forest in the Sherwood simulation suite. Monthly Notices of the Royal Astronomical Society, 471(1), doi:10.1093/mnras/stx1648. ISSN 0035-8711

We study the effect of different feedback prescriptions on the properties of the low redshift (z ≤ 1.6) Ly α forest using a selection of hydrodynamical simulations drawn from the Sherwood simulation suite. The simulations incorporate stellar feedback... Read More

Gas around galaxy haloes - III: hydrogen absorption signatures around galaxies and QSOs in the Sherwood simulation suite (2017)
Journal Article
Meiksin, A., Bolton, J. S., & Puchwein, E. (2017). Gas around galaxy haloes - III: hydrogen absorption signatures around galaxies and QSOs in the Sherwood simulation suite. Monthly Notices of the Royal Astronomical Society, 468(2), doi:10.1093/mnras/stx191. ISSN 0035-8711

Modern theories of galaxy formation predict that galaxies impact on their gaseous surroundings, playing the fundamental role of regulating the amount of gas converted into stars. While star-forming galaxies are believed to provide feedback through ga... Read More

Diagnosing galactic feedback with line broadening in the low redshift Lyα forest (2017)
Journal Article
Viel, M., Haehnelt, M. G., Bolton, J. S., Kim, T., Puchwein, E., Nasir, F., & Wakker, B. P. (2017). Diagnosing galactic feedback with line broadening in the low redshift Lyα forest. Monthly Notices of the Royal Astronomical Society, 467(1), doi:10.1093/mnrasl/slx004. ISSN 0035-8711

We compare the low-redshift (z 0.1) Lyα forest from hydrodynamical simulations with data from the Cosmic Origins Spectrograph. We find the tension between the observed number of lines with b-parameters in the range of 25–45 km s−1 and the prediction... Read More

The Lyman α forest power spectrum from the XQ-100 legacy survey (2016)
Journal Article
Irsic, V., Viel, M., Berg, T. A., D'Odorico, V., Haehnelt, M. G., Cristiani, S., …Bolton, J. S. (2016). The Lyman α forest power spectrum from the XQ-100 legacy survey. Monthly Notices of the Royal Astronomical Society, 466(4), doi:10.1093/mnras/stw3372. ISSN 0035-8711

We present the Lyman α flux power spectrum measurements of the XQ-100 sample of quasar spectra obtained in the context of the European Southern Observatory Large Programme ‘Quasars and their absorption lines: a legacy survey of the high redshift univ... Read More

Inferring the IGM thermal history during reionisation with the Lyman-α forest power spectrum at redshift z ≃ 5 (2016)
Journal Article
Nasir, F., Bolton, J. S., & Becker, G. D. (in press). Inferring the IGM thermal history during reionisation with the Lyman-α forest power spectrum at redshift z ≃ 5. Monthly Notices of the Royal Astronomical Society, doi:10.1093/mnras/stw2147. ISSN 0035-8711

We use cosmological hydrodynamical simulations to assess the feasibility of constraining the thermal history of the intergalactic medium during reionisation with the Lyα forest at z ≃ 5. The integrated thermal history has a measureable impact on the... Read More

Testing the effect of galactic feedback on the IGM at z ∼ 6 with metal-line absorbers (2016)
Journal Article
Keating, L. C., Puchwein, E., Haehnelt, M. G., Bird, S., & Bolton, J. S. (in press). Testing the effect of galactic feedback on the IGM at z ∼ 6 with metal-line absorbers. Monthly Notices of the Royal Astronomical Society, 461(1), doi:10.1093/mnras/stw1306. ISSN 0035-8711

We present models of low- and high-ionization metal-line absorbers (O i, C ii, C iv and Mg ii) during the end of the reionization epoch, at z ∼ 6. Using four cosmological hydrodynamical simulations with different feedback schemes (including the Illus... Read More

Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests (2015)
Journal Article
Boera, E., Murphy, M. T., Becker, G. D., & Bolton, J. S. (2016). Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests. Monthly Notices of the Royal Astronomical Society, 456(1), doi:10.1093/mnrasl/slv172. ISSN 0035-8711

The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter γ. We describe a new method to measure γ using the ratio of flux cu... Read More

Reionization and high-redshift galaxies: the view from quasar absorption lines (2015)
Journal Article
Becker, G. D., Bolton, J. S., & Lidz, A. (in press). Reionization and high-redshift galaxies: the view from quasar absorption lines. Publications of the Astronomical Society of Australia, 32, doi:10.1017/pasa.2015.45. ISSN 1323-3580

Determining when and how the first galaxies reionised the intergalactic medium promises to shed light on both the nature of the first objects and the cosmic history of baryons. Towards this goal, quasar absorption lines play a unique role by probing... Read More

Gas around galaxy haloes - II: hydrogen absorption signatures from the environments of galaxies at redshifts 2 (2015)
Journal Article
Meiksin, A., Bolton, J. S., & Tittley, E. (2015). Gas around galaxy haloes - II: hydrogen absorption signatures from the environments of galaxies at redshifts 2. Monthly Notices of the Royal Astronomical Society, 453(1), doi:10.1093/mnras/stv1682. ISSN 0035-8711

We compare predictions of large-scale cosmological hydrodynamical simulations for neutral hydrogen absorption signatures in the vicinity of 1011–1012.5 M⊙ haloes with observational measurements. Two different hydrodynamical techniques and a variety o... Read More

Simulating the 21 cm forest detectable with LOFAR and SKA in the spectra of high-z GRBs (2015)
Journal Article
Ciardi, B., Inoue, S., Abdalla, F., Asad, K., Bernardi, G., Bolton, J. S., …Zaroubi, S. (2015). Simulating the 21 cm forest detectable with LOFAR and SKA in the spectra of high-z GRBs. Monthly Notices of the Royal Astronomical Society, 453(1), doi:10.1093/mnras/stv1640. ISSN 0035-8711

We investigate the feasibility of detecting 21 cm absorption features in the afterglow spectra of high redshift long Gamma Ray Bursts (GRBs). This is done employing simulations of cosmic reionization, together with estimates of the GRB radio afterglo... Read More

Lyman α emitters gone missing: evidence for late reionization? (2015)
Journal Article
Choudhury, T. R., Puchwein, E., Haehnelt, M. G., & Bolton, J. S. (2015). Lyman α emitters gone missing: evidence for late reionization?. Monthly Notices of the Royal Astronomical Society, 452(1), doi:10.1093/mnras/stv1250. ISSN 0035-8711

We combine high resolution hydrodynamical simulations with an intermediate resolution, dark matter only simulation and an analytical model for the growth of ionized regions to estimate the large scale distribution and redshift evolution of the visibi... Read More

The photoheating of the intergalactic medium in synthesis models of the UV background (2015)
Journal Article
Puchwein, E., Bolton, J. S., Haehnelt, M. G., Madau, P., Becker, G. D., & Haardt, F. (2015). The photoheating of the intergalactic medium in synthesis models of the UV background. Monthly Notices of the Royal Astronomical Society, 450(4), doi:10.1093/mnras/stv773. ISSN 0035-8711

We compare cosmological hydrodynamical simulations combined with the homogeneous metagalactic UV background (UVB) of Haardt & Madau (2012) (HM2012) to observations of the Lyman-alpha forest that are sensitive to the thermal and ionization state of th... Read More

IGM constraints from the SDSS-III/BOSS DR9 Lyα forest transmission probability distribution function (2015)
Journal Article
Lee, K., Hennawi, J., Spergel, D., Weinberg, D., Hogg, D., Viel, M., …Yeche, C. (2015). IGM constraints from the SDSS-III/BOSS DR9 Lyα forest transmission probability distribution function. Astrophysical Journal, 799(2), doi:10.1088/0004-637X/799/2/196. ISSN 0004-637X

The Lyα forest transmission probability distribution function (PDF) is an established probe of the intergalactic medium (IGM) astrophysics, especially the temperature-density relationship of the IGM. We measure the transmission PDF from 3393 Baryon O... Read More

Evidence of patchy hydrogen reionization from an extreme Lyα trough below redshift six (2015)
Journal Article
Becker, G. D., Bolton, J. S., Madau, P., Pettini, M., Ryan-Weber, E. V., & Venemans, B. P. (2015). Evidence of patchy hydrogen reionization from an extreme Lyα trough below redshift six. Monthly Notices of the Royal Astronomical Society, 447(4), doi:10.1093/mnras/stu2646. ISSN 0035-8711

We report the discovery of an extremely long (∼110 Mpc/h) and dark (τeff≳7) Lyα trough extending down to z≃5.5 towards the zem≃6.0 quasar ULAS J0148+0600. We use these new data in combination with Lyα forest measurements from 42 quasars at 4.5≤zem≤6.... Read More

The impact of temperature fluctuations on the large-scale clustering of the Lyα forest (2015)
Journal Article
Greig, B., Bolton, J. S., & Wyithe, J. S. B. (2015). The impact of temperature fluctuations on the large-scale clustering of the Lyα forest. Monthly Notices of the Royal Astronomical Society, 447(3), doi:10.1093/mnras/stu2624. ISSN 0035-8711

We develop a semi-analytic method for assessing the impact of the large-scale IGM temperature fluctuations expected following He ii reionization on three-dimensional clustering measurements of the Lyα forest. Our methodology builds upon the existing... Read More