Faculty of Natural Sciences: Recent submissions
Now showing items 1421-1440 of 2642
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Improved upper limits on the 21 cm signal power spectrum of neutral hydrogen at z ≈ 9.1 from LOFAR
(Oxford University Press, 2020)A new upper limit on the 21 cm signal power spectrum at a redshift of z ≈ 9.1 is presented, based on 141 h of data obtained with the Low-Frequency Array (LOFAR). The analysis includes significant improvements in spectrally ... -
A lack of evolution in the very bright end of the galaxy luminosity function from z 8 to 10
(Oxford University Press, 2020)ABSTRACT We utilize deep near-infrared survey data from the UltraVISTA fourth data release (DR4) and the VIDEO survey, in combination with overlapping optical and Spitzer data, to search for bright star-forming galaxies ... -
Measuring the H I mass function below the detection threshold
(Oxford University Press, 2019-10-30)We present a Bayesian stacking technique to directly measure the H I mass function (HIMF) and its evolution with redshift using galaxies formally below the nominal detection threshold. We generate galaxy samples over ... -
Evaluation of probabilistic photometric redshift estimation approaches for The Rubin Observatory Legacy Survey of Space and Time (LSST)
(Oxford University Press, 2020-09-14)Many scientific investigations of photometric galaxy surveys require redshift estimates, whose uncertainty properties are best encapsulated by photometric redshift (photo-z) posterior probability density functions (PDFs). ... -
Augmenting machine learning photometric redshifts with Gaussian mixture models
(Oxford University Press, 2020-09-11)Wide-area imaging surveys are one of the key ways of advancing our understanding of cosmology, galaxy formation physics, and the large-scale structure of the Universe in the coming years. These surveys typically require ... -
K-CLASH: Strangulation and ram pressure stripping in galaxy cluster members at 0.3 < z < 0.6
(Oxford University Press, 2020-06-26)Galaxy clusters have long been theorized to quench the star formation of their members. This study uses integral-field unit observations from the K-band MultiObject Spectrograph (KMOS) – Cluster Lensing And Supernova ... -
VLA imaging of the XMM-LSS/VIDEO deep field at 1–2 GHz
(Oxford University Press, 2020-06-20)Modern radio telescopes are routinely reaching depths where normal star-forming galaxies are the dominant observed population. Realizing the potential of radio as a tracer of star formation and black hole activity over ... -
Timing the earliest quenching events with a robust sample of massive quiescent galaxies at 2 < z < 5
(Oxford University Press, 2020-06-04)We present a sample of 151 massive (M∗ > 1010 M) quiescent galaxies at 2 <z< 5, based on a sophisticated Bayesian spectral energy distribution fitting analysis of the CANDELS UDS and GOODS-South fields. Our sample includes ... -
SIMBA: the average properties of the circumgalactic medium of 2 ≤ z ≤ 3 quasars are determined primarily by stellar feedback
(Oxford University Press, 2020-10-05)We use the SIMBA cosmological hydrodynamic simulation suite to explore the impact of feedback on the circumgalactic medium (CGM) and intergalactic medium (IGM) around 2 ≤ z ≤ 3 quasars. We identify quasars in SIMBA as the ... -
Constraining the intergalactic medium at z ≈ 9.1 using LOFAR Epoch of Reionization observations
(Advance access publications, 2020)We derive constraints on the thermal and ionization states of the intergalactic medium (IGM) at redshift ≈ 9.1 using new upper limits on the 21-cm power spectrum measured by the LOFAR radio telescope and a prior on the ... -
The faint radio source population at 15.7 GHz – IV. The dominance of core emission in faint radio galaxies
(Oxford University Press, 2020)We present 15-GHz Karl G. Jansky Very Large Array observations of a complete sample of radio galaxies selected at 15.7 GHz from the Tenth Cambridge (10C) survey. 67 out of the 95 sources (71 per cent) are unresolved in the ... -
Infrared luminosity functions and dust mass functions in the EAGLE simulation
(Oxford University Press, 2020)We present infrared luminosity functions and dust mass functions for the EAGLE cosmological simulation, based on synthetic multiwavelength observations generated with the SKIRT radiative transfer code. In the local Universe, ... -
The thousand-pulsar-array programme on MeerKAT – I. Science objectives and first results
(Oxford University Press, 2020)We report here on initial results from the Thousand-Pulsar-Array (TPA) programme, part of the Large Survey Project ‘MeerTime’ on the MeerKAT telescope. The interferometer is used in the tied-array mode in the band from 856 ... -
Variability and transient search in the SUDARE–VOICE field: A new method to extract the light curves
(Oxford University Press, 2020)The VLT Survey Telescope (VST) Optical Imaging of the CDFS and ES1 Fields Survey, in synergy with the SUDARE survey, is a deep optical ugri imaging of the CDFS and ES1 fields using the VST. The observations for the CDFS ... -
Assessing non-linear models for galaxy clustering – II. Model validation and forecasts for Stage IV surveys
(Oxford University Press, 2020)Accurate modelling of non-linear scales in galaxy clustering will be crucial for data analysis of Stage IV galaxy surveys. A selection of competing non-linear models must be made based on validation studies. We provide a ... -
The performance of photometric reverberation mapping at high redshift and the reliability of damped random walk models
(Oxford University Press, 2020-03)Accurate methods for reverberation mapping using photometry are highly sought after since they are inherently less resource intensive than spectroscopic techniques. However, the effectiveness of photometric reverberation ... -
All-sky angular power spectrum – I. Estimating brightness temperature fluctuations using the 150-MHz TGSS survey
(Oxford University Press, 2020)Measurements of the Galactic synchrotron emission are important for the 21-cm studies of the epoch of reionization. The study of synchrotron emission is also useful for quantifying the fluctuations in the magnetic field ... -
Direct parameter inference from global EoR signal with Bayesian statistics
(Oxford University Press, 2020)In the observation of sky-averaged HI signal from Epoch of Reionization (EoR), model parameter inference can be a computation-intensive work, which makes it hard to perform a direct one-stage model parameter inference by ... -
The MeerKAT telescope as a pulsar facility: System verification and early science results from MeerTime
(2020)We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for the newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. MeerKAT is a high-gain ( ) ... -
A new model for including galactic winds in simulations of galaxy formation – I. Introducing the Physically Evolved Winds (PhEW) model
(Oxford University Press, 2020-07-08)The propagation and evolution of cold galactic winds in galactic haloes is crucial to galaxy formation models. However, modelling of this process in hydrodynamic simulations of galaxy formation is oversimplified owing to ...