Observations

Dec 21, 2014

Orbital eccentricities of Be X-ray binaries – continuation from semester 1

2014-2-SCI-016

In this programme we use the small Doppler shifts in a stellar spectrum to measure binary motion of an early type star. We will use SALT’s new high resolution spectrograph to determine the shape of the orbit. This will help us learn about how the neutron star orbiting the early type star was formed.

A search of high redshift radio loud quasars

2014-2-SCI-063

Very distant and radio bright galaxies (quasars) reveal information about the history and evolution of the early Universe. By observing these objects we can learn a lot about the physical properties of the black holes at the centre of these galaxies. Thenumber of known quasars that are very distant, redshift > 5, and also bright at radio wavelengths is small, therefore, a search of new high redshift quasars is important. The new discovered quasars will be observed in all range of wavelengths from gamma to radio waves.

The mass growth of LRGs through mergers

2014-1-MLT-002

The most massive galaxies in the universe are thought to undergo multiple mergers with other galaxies, through which they grow and change form. We will use SALT to accurately measure the distances of pairs of galaxies that are close together on the sky, in order to determine what fraction are likely to merge and how this affects their evolution.

Spectroscopic Observations of Dark-Hearted S0 Galaxies

2014-2-SCI-052

Galaxies in the present day universe fall into two major groups: those that effectively form new stars and those that don’t. Stars form from cosmic gas within galaxies. Thus astronomers believe that star formation ceases when the gas supply runs out. How galaxies come to exhaust their supplies of gas, however, remains unclear. In this project we study 3 unusual galaxies that appear to be crossing the divide from star forming blue galaxies to dead, red systems as a means to better understand how some galaxies become free from cosmic gas that supports star formation.

Dec 20, 2014

Magellanic Cloud Dwarf Novae

2014-2-SCI-074

Accretion disk echo mapping of high-redshift quasars

2014-2-MLT-005

We are determining the luminosity (and therefore the distance) to very distant galaxies by measuring how long it takes for echos to travel from the central super-massive black hole in the core of the galaxy to a disk of material falling into the black hole. The delays are expected to be of the order of days.

Dec 19, 2014

Orbital eccentricities of Be X-ray binaries – continuation from semester 1

2014-2-SCI-016

In this programme we use the small Doppler shifts in a stellar spectrum to measure binary motion of an early type star. We will use SALT’s new high resolution spectrograph to determine the shape of the orbit. This will help us learn about how the neutron star orbiting the early type star was formed.

Spectroscopic Observations of Dark-Hearted S0 Galaxies

2014-2-SCI-052

Galaxies in the present day universe fall into two major groups: those that effectively form new stars and those that don’t. Stars form from cosmic gas within galaxies. Thus astronomers believe that star formation ceases when the gas supply runs out. How galaxies come to exhaust their supplies of gas, however, remains unclear. In this project we study 3 unusual galaxies that appear to be crossing the divide from star forming blue galaxies to dead, red systems as a means to better understand how some galaxies become free from cosmic gas that supports star formation.

Spectroscopic Follow-up of Type Ia Supernovae Discovered by the Dark Energy Survey

2014-2-SCI-070

A category of exploding stars known as type Ia supernovae (SNe Ia) are key to further understanding the nature of “dark energy”, an unknown force which dominates the content of the Universe and is responsible for the observed accelerated expansion of the Universe. The Dark Energy Survey (DES) is an international experiment specifically aimed at measuring the expansion history of the universe in an effort to pin down the physical properties of dark energy. The Southern African Large Telescope (SALT), located in Sutherland is ideally suited to enable astronomers around the world, particularly in South Africa and on the African continent, to observe these astrophysical “standard candles” and shed light on the enigmatic properties of dark energy. Recently, SALT has successfully observed and spectroscopically confirmed it’s first SNe Ia from DES and in this proposal we aim to significantly increase the number of SNe Ia observed by SALT. These measurements will allow us to study the properties of these astrophysical phenomena, and better understand the nature of dark energy.

Dec 18, 2014

Spectroscopic Observations of Dark-Hearted S0 Galaxies

2014-2-SCI-052

Galaxies in the present day universe fall into two major groups: those that effectively form new stars and those that don’t. Stars form from cosmic gas within galaxies. Thus astronomers believe that star formation ceases when the gas supply runs out. How galaxies come to exhaust their supplies of gas, however, remains unclear. In this project we study 3 unusual galaxies that appear to be crossing the divide from star forming blue galaxies to dead, red systems as a means to better understand how some galaxies become free from cosmic gas that supports star formation.