Physics and Astronomy: Recent submissions
Now showing items 341-360 of 520
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Significance levels of common frequencies extracted from multiple data sets
(Oxford University Press, 2020)Large monitoring campaigns, particularly those using multiple filters, have produced replicated time series of observations for literally millions of stars. The search for periodicities in such replicated data can be ... -
Constraining the reionization history using deep learning from 21-cm tomography with the Square Kilometre Array
(Oxford University Press, 2020)Upcoming 21-cm surveys with the SKA1-LOW telescope will enable imaging of the neutral hydrogen distribution on cosmological scales in the early Universe. These surveys are expected to generate huge imaging data sets that ... -
The rest-frame UV luminosity function at z 4: A significant contribution of AGNs to the bright end of the galaxy population
(Oxford University Press, 2020)We measure the rest-frame ultraviolet (UV) luminosity function (LF) at z ∼ 4 self-consistently over a wide range in absolute magnitude (−27 ≲ MUV ≲ −20). The LF is measured with 46 904 sources selected using a photometric ... -
A spectroscopic analysis of the eclipsing nova-like EC 21178−5417 – discovery of spiral density structures
(Oxford University Press, 2020)We present phase-resolved optical spectroscopy of the eclipsing nova-like cataclysmic variable EC 21178−5417 obtained between 2002 and 2013. The average spectrum of EC 21178−5417 shows broad double-peaked emission lines ... -
Evidence for cosmic acceleration with next-generation surveys: A model-independent approach
(Oxford University Press, 2020)We quantify the evidence for cosmic acceleration using simulations of H(z) measurements from SKA- and Euclid-like surveys. We perform a non-parametric reconstruction of the Hubble parameters and its derivative to obtain ... -
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 ...