AQ Col (EC~05217-3914) is one of the first detected pulsating subdwarf B (sdB) stars and has been considered to be a single star. However, its periodic pulsation timing variations indicate that AQ Col may not be a single star. We present pulsation period variations observed over twenty-four years and derived orbital characteristics these would imply …
We study the clustering of Gravitational Wave (GW) merger events and Supernovae IA (SN), as cosmic tracers in Luminosity Distance Space. We modify the publicly available CAMB code to numerically evaluate auto- and cross- power spectra for the different sources, including Luminosity Distance Space distortion effects generated by peculiar velocities and lensing convergence. We perform …
We train neural networks to perform likelihood-free inference from (25h−1Mpc)2 2D maps containing the total mass surface density from thousands of hydrodynamic simulations of the CAMELS project. We show that the networks can extract information beyond one-point functions and power spectra from all resolved scales (≳100h−1kpc) while performing a robust marginalization over baryonic physics at the field …
Following the reported detection of an absorption profile associated with the 21~cm sky-averaged signal from the Cosmic Dawn by the EDGES experiment in 2018, a number of experiments have been set up to verify this result. This paper discusses the design process used for global 21~cm experiments, focusing specifically on the Radio Experiment for the …
Astrophysical processes such as feedback from supernovae and active galactic nuclei modify the properties and spatial distribution of dark matter, gas, and galaxies in a poorly understood way. This uncertainty is one of the main theoretical obstacles to extract information from cosmological surveys. We use 2,000 state-of-the-art hydrodynamic simulations from the CAMELS project spanning a …
The HERA telescope, an array of 350 antennas situated next to MeerKAT in the Northern Cape province of South Africa, is being built by a team of local artisans from the town of Carnarvon. It has now released its first set of observations to the world, giving a glimpse of what the Universe looked like about …
We investigate the 1/f noise of the Five-hundred-meter Aperture Spherical Telescope (FAST) receiver system using drift-scan data from an intensity mapping pilot survey. All the 19 beams have 1/f fluctuations with similar structures. Both the temporal and the 2D power spectrum densities are estimated. The correlations directly seen in the time series data at low …
We present a novel 2D flux density model for observed HI emission lines combined with a Bayesian stacking technique to measure the baryonic Tully-Fisher relation below the nominal detection threshold. We simulate a galaxy catalogue, which includes HI lines described either with Gaussian or busy function profiles, and HI data cubes with a range of …
Traditional large-scale models of reionization usually employ simple deterministic relations between halo mass and luminosity to predict how reionization proceeds. We here examine the impact on modelling reionization of using more detailed models for the ionizing sources as identified within the 100 Mpc/h cosmological hydrodynamic simulation Simba, coupled with post-processed radiative transfer. Comparing with simple (one-to-one) models, the …
Using a sample of 67 galaxies from the MIGHTEE Survey Early Science data we study the HI-based baryonic Tully-Fisher relation (bTFr), covering a period of ∼one billion years (0≤z≤0.081). We consider the bTFr based on two different rotational velocity measures: the width of the global HI profile and Vout, measured as the outermost rotational velocity from the …
