We discuss a method to determine the reliability of source finders within the context of upcoming Hi surveys. Assuming that the noise is symmetric and that real sources have positive total flux, we use sources with negative flux to assign to each positive detection a probability of being real.

The identity of the progenitors of type-Ia supernovae (SNe Ia) is a major puzzle. SN Ia rates are providing new clues, through the delay-time distribution (DTD) of these events. Recent measurements and analyses point to a ~t^–1 DTD, suggesting that at least some SNe Ia result from double white dwarf mergers.

This paper discusses the results of basic source finding tests with the duchamp source finder on different source models. We find duchamp to be a powerful source finder, capable of reliably detecting sources down to low signal-to-noise ratios. duchamp's measurements of basic source parameters, however, are affected by systematic errors.

A new wavelength calibration method which combines short-exposure and long-exposure spectral lines for LAMOST is presented in this paper. Compared with traditional calibration methods which only use short exposures and strong lines, the results of experiments show that the proposed method leads to a calibration of higher precision.

In this paper, we implement a 2D–1D wavelet decomposition to obtain an efficient way of denoising data cubes from spectroscopic imaging surveys. We conduct different simulations to evaluate the usefulness of the algorithm as part of a source finding pipeline.

The Characterised Noise Hi source finder uses a novel approach to find sources in Hi spectral line datacubes using matched filtering. The concept, initial implementation and testing are presented here.

We observed DK CVn and analysed the BVR light curves with phoebe v0.31a software. Several flares were detected and modelled by the OPEA. The model parameters demonstrated that the flares are the same as those of UV Ceti stars. This study reveals that DK CVn should be a chromospherically active binary star.

We discuss optimal source detection with multiwavelength imaging data using a color-neutral approach representing a more general version of the so-called ‘chi-squared’ technique. We discuss its performance with four-band data from the WISE mission and suggest applications to the multifrequency data cubes of the ASKAP surveys.

From medium-resolution spectra we derive the C and N sensitive index, δC, for 97 giants and infer abundances of Fe, Na, Si, Ca, Zr and Ba for 13 stars. δC is correlated with Na and could imply that a second era of star formation has revealed the products of CNO-cycle burning.

We discuss the broad range of new and important high-angular-resolution science that will be enabled by the Square Kilometre Array. We highlight the fact that high angular resolution, requiring baselines greater than 1000 km, provides a rich science case with projects from many areas of astrophysics, including important contributions to key SKA science.

We have compared duchamp and manual identification methods for identifying masers in the Galactic plane survey HOPS. We find noise in the data is the limiting factor determining efficiency of both methods. duchamp may be useful for very large datasets, but the manual method is quicker for smaller datasets.

The EMU survey with ASKAP aims to utilise an automated source identification and measurement approach that is demonstrably optimal. A key stage in source extraction methods is the background estimation and the choice of a threshold high enough to reject false sources, yet not so high that the catalogues are significantly incomplete. In this analysis, we present results from testing the SExtractor, Selavy (Duchamp), and sfind source extraction tools on simulated radio continuum data.

A procedure to estimate the aerosol extinction parameters of Angstrom’s formula using data taken with broadband filters is presented. The method is based on the determination of the equivalent mean wavelength monochromatic magnitudes from the heterochromatic ones using an iterative approach, correcting subsequently the water-vapour extinction in the longer-wavelength filters.

In this work, the solution of the standard V light curve of EP And, an over contact binary system, was obtained using the phoebe program. The structure and evolutionary status of the system is discussed. Times of minima data (‘O–C curve’) were analyzed. It was found that a third body with a period of 41.20 yr and mass 0.15 M_sun is orbiting around the system. Also, a modulating period of an 11.72-yr cycle along with a relative period increase of

were obtained, which were attributed to the magnetic activity cycle and the mass transfer with rate

between the components, respectively.

Electron and proton impact Stark width dependences on the upper level ionization potential within neutral calcium spectral series were studied. The emphasis is on the term structure and temperature influence on these dependences. Using these dependences, predictions were made for lines not being measured experimentally or calculated theoretically until now.

We have developed a method for simultaneously finding and fitting HI absorption lines in radio data by using multi-nested sampling, a Bayesian Monte Carlo algorithm. The method is tested on a simulated ASKAP data cube, and is shown to be produce reliable detections in low signal-to-noise data.

Large-scale imaging surveys have been instrumental in finding the least luminous galaxies, uncovering inconsistencies between the CDM paradigm and galaxy properties, and reopening the debate about the building block scenario for the Milky Way. Progress in the field is discussed and attention drawn to future initiatives aimed at better understanding the phenomenon of 'ultra-faint dwarf galaxy'.

Detection thresholds in polarized intensity and polarization bias correction are investigated for surveys where the polarization information is obtained from RM synthesis. The false detection rate of sources in polarized intensity is investigated for images with non-Gaussian noise in Stokes Q and U.