Browsing Research Articles (Physics) by Subject "Astronomy"
Now showing items 21-40 of 85
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Disentangling non-gaussianity, bias, and general relativistic effects in the galaxy distribution
(American Physical Society, 2012)Local non-Gaussianity, parametrized by f NL , introduces a scale-dependent bias that is strongest at large scales, precisely where general relativistic (GR) effects also become significant. With future data, it should ... -
Dusty starbursts masquerading as ultra-high redshift galaxies in jwst ceers observations
(American Astronomical Society, 2023)Lyman-break galaxy (LBG) candidates at z 10 are rapidly being identified in James Webb Space Telescope (JWST)/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of restframe UV ... -
Efficient long-range active galactic nuclei (agns) feedback affects the low-redshift lyα forest
(American Astronomical Society, 2023)Active galactic nuclei (AGNs) feedback models are generally calibrated to reproduce galaxy observables such as the stellar mass function and the bimodality in galaxy colors. We use variations of the AGN feedback implementations ... -
Exomol line lists – xliv. Infrared and ultraviolet line list for silicon monoxide (28si16o)
(Oxford University Press, 2022)A new silicon monoxide ( 28Si16O) line list covering infrared, visible, and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions ... -
Feature guided training and rotational standardization for the morphological classification of radio galaxies
(Oxford University Press, 2023)State-of-the-art radio observatories produce large amounts of data which can be used to study the properties of radio galaxies. However, with this rapid increase in data volume, it has become unrealistic to manually process ... -
The fore ground transfer function for H I intensity mapping signal reconstruction: MeerKLASS and precision cosmology applications
(Oxford University Press, 2023)Blind cleaning methods are currently the preferred strategy for handling foreground contamination in single-dish H I intensity mapping surv e ys. Despite the increasing sophistication of blind techniques, some signal loss ... -
Galaxy and Mass Assembly (GAMA): Mid-infrared properties as tracers of galaxy environment
(EDP Sciences, 2023)We investigate how different mid-infrared (mid-IR) properties of galaxies are correlated with the environment in which the galaxies are located. For this purpose, we first study the dependence of galaxy clustering on the ... -
Gaussian process regression for foreground removal in hi intensity mapping experiments
(Oxford University Press, 2022)We apply for the first time Gaussian Process Regression (GPR) as a foreground removal technique in the context of single-dish, low redshift H I intensity mapping, and present an open-source PYTHON toolkit for doing so. We ... -
Global simulations of multi-frequency hf signal absorption for direct observation of middle atmosphere temperature and composition
(Wiley, 2023)This paper presents the first numerical study on a new concept for the direct measurement of D-region absorption in the high-frequency (HF) band. Numerical simulations based on the Appleton-Hartree and Garrett equations ... -
Gravitational signal propagation in the double pulsar studied with the MeerKAT telescope
(Hans Publishers, 2022)The double pulsar PSR J0737−3039A/B has offered a wealth of gravitational experiments in the strong-field regime, all of which general relativity has passed with flying colours. In particular, among current gravity ... -
H I intensity mapping with MeerKAT: Power spectrum detection in cross-correlation with WiggleZ galaxies
(Oxford University Press, 2023)We present a detection of correlated clustering between MeerKAT radio intensity maps and galaxies from the WiggleZ Dark Energy Survey. We find a 7.7σ detection of the cross-correlation power spectrum, the amplitude of which ... -
Herschel-atlas/Gama: a difference between star formation rates in strong-line and weak-line radio galaxies
(OUP, 2013)We have constructed a sample of radio-loud objects with optical spectroscopy from the Galaxy and Mass Assembly (GAMA) project over the Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) Phase 1 fields. ... -
Herschel-ATLAS/GAMA: What determines the far-infrared properties of radio galaxies?
(OUP, 2013)We perform a stacking analysis of Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) data in order to obtain isothermal dust temperatures and rest-frame luminosities at 250 µm (L250), for a well-defined sample ... -
Hi global scaling relations in the wise-whisp survey
(Oxford University Press, 2021)We present the global scaling relations between the neutral atomic hydrogen gas, the stellar disk and the star forming disk in a sample of 228 nearby galaxies that are both spatially and spectrally resolved in HI line ... -
High-precision half-life determination of 14O via direct β counting
(Springer, 2022)The half-life of the superallowed Fermi β+ emitter 14O was determined to high precision via a direct β counting experiment performed at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. The result, T1/2( 14O) ... -
Hot subdwarf stars in close-up view IV. Helium abundances and the 3He isotopic anomaly of subdwarf B stars
(EDP Sciences, 2013)Atmospheric parameters and helium abundances of 44 bright subdwarf B stars have been determined. More than half of our sample consists of newly discovered stars from the Edinburgh Cape survey. We showed that effective ... -
Hot white dwarfs and pre-white dwarfs discovered with SALT
(Oxford University Press, 2023)The Southern African Large Telescope survey of helium-rich hot subdwarfs aims to explore evolutionary pathways among groups of highly evolved stars. The selection criteria mean that several hot white dwarfs and related ... -
How open data and interdisciplinary collaboration improve our understanding of space weather: A risk and resiliency perspective
(Frontiers Media, 2022)Space weather refers to conditions around a star, like our Sun, and its interplanetary space that may affect space- and ground-based assets as well as human life. Space weather can manifest as many different phenomena, often ... -
Hydra I: An extensible multi-source-finder comparison and cataloguing tool
(Cambridge University Press, 2023)The latest generation of radio surveys are now producing sky survey images containing many millions of radio sources. In this context it is highly desirable to understand the performance of radio image source finder (SF) ... -
Hydra ii: Characterisation of Aegean, Caesar, profound, pybdsf, and selavy source finders
(Cambridge University Press, 2023)We present a comparison between the performance of a selection of source finders using a new software tool called Hydra. The companion paper, Paper I, introduced the Hydra tool and demonstrated its performance using ...