Events

Oct
20
Fri
Journal Club / Group Meeting – KABELO @ Maths Seminar Room - H1-401
Oct 20 @ 3:00 pm – 4:00 pm
Group Meeting Speaker: Kabelo Kesebonye


Title: HIRAX commissioning and instrument characterization


Abstract: An exciting frontier of radio astronomy is using the redshifted 21-cm emission of neutral hydrogen to reconstruct a three-dimensional map of large-scale structure in the universe. These maps encode a faint imprint, known as baryon acoustic oscillations (BAOs), that correspond to remnant ripples left behind by sound waves echoing through the plasma of the early universe. Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a new experiment which will constrain BAOs, open new views into structure formation and the universe’s expansion history, and shedding light on the mystery of dark energy. HIRAX will map the southern sky over a frequency range of 400-800 MHz, located in the Karoo, Nothern Cape. HIRAX will be complementing Canadian Hydrogen Intensity Mapping Experiment (CHIME), which is surveying the northern sky at the same frequency range. My project focuses on the assembly and characterization of the 8-element prototype array sited at HartRAO, which is a critical milestone along the path to constructing the full array which will consist of 1024 elements.


Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles.



Group Meeting – forum for an official research presentation; one speaker per slot, with students preparing and presenting a 20-25 minute talk on their research. Postdocs and staff may opt to give a blackboard talk.

Oct
24
Tue
Public Talk – Vishnu Jejjala (Wits) @ STEC
Oct 24 @ 6:00 pm – 7:00 pm

Title:       The Atoms of Spacetime

Abstract:        What did Einstein do that was so remarkable? What are black holes and do we need quantum gravity to understand them? Do black holes have thermodynamics and what does that mean? Is spacetime emergent? From what?

In 1915, Einstein proposed a new theory of gravity. Soon, it was discovered that this theory of general relativity has special kinds of solutions that came to be known  as black holes. They are distinguished by having singularities (places where gravity becomes so strong that our classical notion of space and time breaks down) as well as event horizons (regions from which even light cannot escape).

Using the rules of quantum theory leads us to conclude that black holes obey laws analogous to the principles of thermodynamics. Thermodynamics, originally developed to understand steam engines, is the study of things like heat, work, energy, efficiency, and entropy. Entropy in normal matter (like a gas in a room) counts the number of different ways a large number of microscopic atoms can be arranged. Macroscopic properties of matter can be understood by averaging over all of the possible microscopic configurations.

The fact that black holes carry entropy suggests that spacetime can also be thought of as being composed of some sort of “atoms” at a fundamental level. What would the implications of that be?

In some simplified cases we can (theoretically) construct the “microscopic” configurations of black holes. Features of black hole geometries such as the event horizon and singularity arise as a consequence of averaging over many states. By studying these theoretical models of black holes, we get hints about how spacetime can be emergent. Circumstantial evidence suggest that these lessons transfer to astrophysical settings as well.

Oct
26
Thu
Seminar – Vishnu Jejjala (Wits) @ STEC Lecture Room
Oct 26 @ 12:00 pm – 1:00 pm

Title: TBD

Abstract: TBD

Oct
27
Fri
Journal Club / Group Meeting – QING-BO @ Maths Seminar Room - H1-401
Oct 27 @ 3:00 pm – 4:00 pm
Group Meeting Speaker: Qing-bo Ma
Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles.

Group Meeting – forum for an official research presentation; one speaker per slot, with students preparing and presenting a 20-25 minute talk on their research. Postdocs and staff may opt to give a blackboard talk.

Nov
3
Fri
Journal Club / Obs Cos Meeting @ Maths Seminar Room - H1-401
Nov 3 @ 3:00 pm – 4:00 pm

Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles. Students to bring papers of interest that they’ve found on the arXiv (https://arxiv.org/archive/astro-ph).

Obs Cos – forum to discuss your own research informally and to bring up any issues you’re having, current results, etc. Please load any images/figures onto the ACRU wiki (http://acru.ukzn.ac.za/~wiki/w/index.php/Cosmology_Group_Meeting) .

Nov
10
Fri
Journal Club / Group Meeting – PRECIOUS @ Maths Seminar Room - H1-401
Nov 10 @ 3:00 pm – 4:00 pm
Group Meeting Speaker: Precious Sikhosana
Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles.

Group Meeting – forum for an official research presentation; one speaker per slot, with students preparing and presenting a 20-25 minute talk on their research. Postdocs and staff may opt to give a blackboard talk.

Nov
16
Thu
Seminar – Denis Tramonte (ACRU) @ STEC Lecture Room
Nov 16 @ 12:00 pm – 1:00 pm

Title: TBA

Abstract: TBA

Nov
17
Fri
Journal Club / Obs Cos Meeting @ Maths Seminar Room - H1-401
Nov 17 @ 3:00 pm – 4:00 pm

Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles. Students to bring papers of interest that they’ve found on the arXiv (https://arxiv.org/archive/astro-ph).

Obs Cos – forum to discuss your own research informally and to bring up any issues you’re having, current results, etc. Please load any images/figures onto the ACRU wiki (http://acru.ukzn.ac.za/~wiki/w/index.php/Cosmology_Group_Meeting) .

Nov
24
Fri
Journal Club / Group Meeting – DEVIN @ Maths Seminar Room - H1-401
Nov 24 @ 3:00 pm – 4:00 pm
Group Meeting Speaker: Devin Crichton
Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles.

Group Meeting – forum for an official research presentation; one speaker per slot, with students preparing and presenting a 20-25 minute talk on their research. Postdocs and staff may opt to give a blackboard talk.

Dec
1
Fri
Journal Club / Obs Cos Meeting @ Maths Seminar Room - H1-401
Dec 1 @ 3:00 pm – 4:00 pm

Journal Club – discussion around recent arXiv or any interesting/relevant papers; the purpose is to keep up to date on research elsewhere and to scientifically critique the articles. Students to bring papers of interest that they’ve found on the arXiv (https://arxiv.org/archive/astro-ph).

Obs Cos – forum to discuss your own research informally and to bring up any issues you’re having, current results, etc. Please load any images/figures onto the ACRU wiki (http://acru.ukzn.ac.za/~wiki/w/index.php/Cosmology_Group_Meeting) .