Observations

Aug 20, 2019

SALT Observations of Planck Clusters

2018-1-SCI-041

Identification and redshift determination of galaxy clusters.

Spectroscopic observations of four candidate post-binary interaction products

2019-1-SCI-009

Spectroscopic observations of four candidate post-binary interaction products

Study of the hosts’ properties of extremely luminous cosmic catastrophes.

2019-1-SCI-029

Massive stars (mass > 10 Solar mass) end their lives through violent explosions known as Core-collapse Supernovae (CCSNe). During CCSNe the cores of the stars get collapsed to Neutron Star or Black-Hole and the outer shells are expelled in space with a catastrophe. We have also found Superluminous Supernovae (SLSNe) which are 10-100 times luminous with larger timescale than known CCSNe. Present theoretical models can not explain all their observed features very consistently. So, apart from the direct investigations of the transients, indirect probes are also required to break the degeneracies in the theories. One such program is to study the environments of these brilliant catastrophes and to investigate how they differ from that of canonical CCSNe. In this project we will study the spectral lines of the hosts of Hydrogen (H) poor SNe which are extremely luminous, and associated with massive progenitors.

Aug 19, 2019

Long period near-contact giant eclipsing binary candidates

2019-1-SCI-002

Very little is known about binary star mergers. In 2008, a binary star that merged to become a single star, V1309 Scorpii, was observed. We have identified several similar binary stars which may comprise two red giant stars that are on the brink of merging – they orbit each other so closely that they are almost touching. Spectroscopic observations of some of these objects will be made using SALT, with the aim of measuring the masses of the stars and so confirming their nature. These observations will give us the opportunity to identify and characterise binary mergers before they merge, allowing us to advance our understanding of so-called red novae.

Probing the Lyman alpha halos around z>2.5 radio loud quasars

2019-1-SCI-018

Looking for extened Lyman alpha halos around quasars

HRS monitoring of yellow symbiotic systems

2019-1-MLT-008

We propose to obtain high resolution (R~40000) high S/N (≳50) spectra for two dozens of so called yellow symbiotic systems using HRS spectrograph in MR mode. The aim of the proposal is to use HRS spectra for the radial velocity monitoring and to measure abundances of chemical elements. Radial velocities will be derived through cross-correlation technique. Abundances will be measured using the spectral synthesis employing the method of standard LTE analysis. We will also look for possible abundance anomalies due to, e.g., former mass transfer pollution. We expect to obtain new information about orbital parameters of these systems. Using it together with new Gaia DR2 distances we are going to revise and put new constraints on the physical parameters (temperature, luminosity, abundances) of these giants. It seems be very likely that these objects may turn out to have significantly larger diameters, and so be located at longer distances, be significantly colder and more luminous – the bright giants rather than a normal giants

Asymmetry is Destiny: Wolf-Rayet Binary Stars as GRB Progenitors

2018-2-MLT-005

This program aims to use the recently-commissioned high-precision spectropolarimetry mode of RSS to probe the prodigious mass-loss from certain massive evolved stars known as Wolf-Rayet stars which are in binary systems. These objects are possible progenitors of Gamma-Ray Bursts, which are the most energetic explosions yet known, and can be seen across the entire known universe.

Symbiotic stars – important tracers of late evolutionary stages III

2018-1-MLT-005

We propose a large spectroscopic monitoring of a sample of Magellanic symbiotic stars composed of cold red giant stars and hot white dwarfs, which challenge the binary star evolution models because they do not predict their existence. Our proposed observations will allow us to measure the masses of the two stars in the binary system. They will also help us to understand the formation and evolution of these theoretically impossible although existing binaries.

The Rotation Curves of IR Selected Super Spirals

2019-1-SCI-028

Super spirals are the largest, most massive, fastest rotating spiral galaxies in the universe. We are measuringhow fast they spin to determine their dark matter content and to try and understand how they got to be sobig.

Monitoring candidate Be+white dwarf binaries in the Magellanic Clouds

2019-1-MLT-009

We are obtaining spectra of a new class of very massive, hot and energetic binaries that contain amassive star with a disk around it, and a white dwarf of high mass that appears to be sporadicallyigniting nuclear fusion.