Observations

Dec 12, 2018

Optical Spectroscopy for the NuSTAR Serendipitous Survey with SALT

2018-2-MLT-006

The cosmic X-ray background (CXB) was first discovered in the early 1960’s, several years before the detection of the cosmic microwave background (CMB). However, unlike the CMB, which is truly diffuse in origin, the CXB is dominated by the emission from high-energy distant point sources: Active Galactic Nuclei (AGNs), the sites of intense black-hole growth. Surveys with Chandra and XMM-Newton have resolved ≈ 70–90% of the CXB at low energies ( 10 keV observatory with focusing optics. We focus our study on NuSTAR serendipitous sources to identify spectral features in order to measure the distances to these sources (redshifts), as well as to establish their classification and characteristics. In order to achieve our goals we aim to obtain longslit spectra with the Robert Stobie Spectrograph (RSS), mounted at prime focus of SALT, of 17 NuSTAR serendipitous sources.

Observing the Transient Universe

2018-2-LSP-001

This large SALT program is aimed at studying “things that go bang in the night”, namely transient objects in the Universe which either are newly discovered objects, or known objects who suddenly change their appeatance. Such things include binary stars with accreting compact companions, many of them X-ray or gamma ray sources, eruptive stars which suddenly brighten, black holes systems, including active galaxies powered by them, and all manner of explosions including the most energetic of all, gamma ray bursts.

Dec 11, 2018

The Lithium Abundance of the Large Magellanic Cloud

2018-2-SCI-006

The creation of the first chemical elements, which took place just minutes after the Big Bang, provides an intimate view of the physical laws that governed our Universe during its first moments. At present, the Standard Model of cosmology and particle physics is unable to fully explain the relative abundance of these primordial elements. In particular, there is a significant disagreement between the measured and predicted abundance of lithium. We propose to conduct a novel survey that will provide a new, reliable measure of the lithium abundance of gas clouds in a nearby galaxy.

Extending the sample of classical Cepheids with accurately determined physical parameters

2018-1-MLT-007

Classical Cepheids are ones of the most important objects in the astrophysics. They are the key objects for the calibration of the distance scale in the universe and determination of the Hubble constant. Yet our knowledge on them was quite poor. Only recently we have started to get to know more about the physical properties of these stars. The breakthrough came with the discovery of classical Cepheids in eclipsing binary systems, which let us determine very precisely such important parameters like mass or size of the star. The observed Cepheid is important because it has the period longer than any other Cepheid in a binary system analyzed before. The wide range of periods of analyzed Cepheids means better sample for statistical analysis.

Intermediate mass black holes or very massive stars in star-forming galaxies

2017-1-MLT-003

We are looking for intermediate mass black holes or very massive stars in star-forming galaxies

SALT Spectroscopy of Gaia Hypervelocity Stars

2018-2-SCI-027

Following fast-moving stars found by Gaia. @_sublunar_ @kenjshen

Magellanic Cloud Nova Shells

2018-2-SCI-014

When novae erupt, the white dwarf in a close binary system ejects about an Earth-mass of hydrogen gas at speeds of a few thousand km/sec. About half of those ejected shells are seen decades later as glowing, expanding blobs of gas, but half are not. We’re surveying the Magellanoc Clouds to determine why some shells become visible, while others don’t.

Following luminous novae into their quiescent phase

2018-2-SCI-035

Follow two unusual and interesting novae as the outburst has ended and mass transfer onto the white dwarf is srating again. Oneof the two novae has a strong magnetized white dwarf, the other was an unusually luminous nova.

Observing the Transient Universe

2018-2-LSP-001

This large SALT program is aimed at studying “things that go bang in the night”, namely transient objects in the Universe which either are newly discovered objects, or known objects who suddenly change their appeatance. Such things include binary stars with accreting compact companions, many of them X-ray or gamma ray sources, eruptive stars which suddenly brighten, black holes systems, including active galaxies powered by them, and all manner of explosions including the most energetic of all, gamma ray bursts.

Dec 10, 2018

Characterising high-frequency pulsating A-type stars found with SuperWASP

2018-2-SCI-017

Observations of hot of variable stars to determine their fundament properties through spectroscopy.