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Undergraduate Projects

4th year Research Project option in 2014/15 (PA4970)
Are there any supergiant fast X-ray transients masquerading as gamma-ray bursts?

Supergiant Fast X-ray Transients (SFXTs) are a class of High Mass X-ray Binaries (HMXBs) associated with OB supergiants and characterized by short flares. These objects regularly trigger the Swift Burst Alert Telescope, which was actually designed to catch gamma-ray bursts, and while most are identified as SFXTs, it is possible that a handful of these are missed and are archived into the Swift GRB Repository as hard-spectrum, unusual gamma-ray bursts. This project aims to identify SFXTs which masquerade as GRBs, and robustly test the nature of these objects.

Project goals:
To understand the distinct characteristics of SFXTs and GRBs, and analyse current observational X-ray data from 3 unusual GRB afterglows to compare these with known SFXTs.

Skills: Data analysis, literature search, computational analysis

Starting reference:
The Swift Supergiant Fast X-ray Transients Project

Nature of Project: Analysis and interpretation of data from the Swift satellite
Degree(s) for which the project is suitable: Any


4th year Research Project option in 2013/14 (PA4970)
To break or not to break? The origins of featureless gamma-ray burst afterglows

The vast majority of gamma-ray burst X-ray afterglows show complex patterns of power law decay breaks and flaring. There exist, however, a small number of bursts with smooth, featureless fading as seen with Swift's X-ray Telescope. The first example of these was noted in 2006, at exactly the time when the 'canonical' steep->flat->steep->steeper X-ray decay was published, and this featureless afterglow belonged to a particularly energetic gamma-ray burst GRB 061007. The parameters which differentiate bursts with featured from those with featureless afterglow decays are not known, and this project undertakes an in-depth study of a subsample of bursts to shed light on this issue.

Project goals:
The outline is to identify a subsample of flare-free, featureless (post-500-second) afterglows, and devise a method to fit the X-ray and optical light curves and provide a measure of light curve features (ie how do we judge that a light curve is featureless?). Then gather the properties of these sources in prompt, afterglow and host data archived on ADS or GCN Circulars and search for any common properties that might explain the lack of features when compared to the general GRB population. The classic featureless GRB is 061007, which was one of the most energetic bursts discovered, and a recent example has emerged which looks at the outset rather similar. GRB 130907A is a well-observed recent burst which may be featureless from 500 s onwards in X-rays, and deserves detailed individual study.

The project may look at the subsample light curve and archive burst and host properties compared with other GRB samples, and/or may focus on GRB 130907A and include spectral study and multiwavelength data from gamma-rays to radio to solve the closure relations of the GRB fireball model.

Skills and background reading:
Data analysis, literature search, basic computational analysis
Evidence for a Canonical GRB Afterglow Light Curve in the Swift/XRT Data: Nousek J.A. et al. 2006, ApJ, 642, 389 preprint
Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs (Section 5 only): Evans P.A. et al. 2009, MNRAS, 397, 1177 preprint

Nature of Project: analysis and interpretation of data from the Swift X-ray Telescope

Suitable for any degree



3rd year Pair Project option in 2014/15 (PA3920)
The faintest gamma-ray bursts

A number of gamma-ray-burst-detecting satellites are in operation, each with its own unique set of detection parameters including energy range, count rate thresholds and sky coverage. The INTEGRAL mission reaches to the very faintest detectable GRBs, and a new type of trigger is being trialled to recover bursts which are even weaker, namely subthreshold. This project will look at the subthreshold GRB afterglow limits and detections to find out whether these could be a new population of explosive events, or the weak tail of the known GRB populations from both the INTEGRAL and Swift missions.

Project goals:
To gain practical experience of handling satellite data, to appreciate transient detection techniques employed by different missions, to analyse these and other data to make statistical comparisons and draw conclusions on the likely parent population.

Skills: Data analysis, literature search, computational and statistical analysis.

Starting references:
Global characteristics of GRBs observed with INTEGRAL and the inferred large population of low-luminosity GRBs,
Foley et al. 2008
The weak INTEGRAL bursts GRB 040223 and GRB 040624: an emerging population of dark afterglows, Filliatre et al. 2006

Nature of Project: Analysis and interpretation of satellite data
Degree(s) for which the project is suitable: Any


3rd year Pair Project option in 2013/14 (PA3920)
The gamma-ray burst population as seen by different satellite missions

A number of gamma-ray-burst-detecting satellites are in operation, each with its own unique set of detection parameters including energy range, count rate thresholds and sky coverage. This project will compare and contrast the gamma-ray burst samples detected by each mission, to determine whether these are drawn from the same parent population or rather comprise different classes of gamma-ray burst.

Project goals:
To analyse current observational data, gain an understanding of the transient detection techniques employed by different missions, collate additional information from the literature and compare a number of samples.

Skills: data analysis, literature search, basic computational analysis

Nature of Project: analysis and interpretation of satellite data

Suitable for any degree



4th year Advanced Study Project option in 2014/15 (PA4440)
Collision of G2 with the Galactic Centre black hole

A fast moving infrared excess source, named G2, appears to be on an eccentric orbit which passed very close to the Milky Way central black hole in spring 2014. Astronomers have followed it closely, and a large dataset is building up. But what is the nature of G2, what impact do G2 and the Galactic Centre black hole have on each other and what are the predictions for the future of these two systems?

Suggested reading to start with:
Gillessen S. et al., 2012, Nature, 481, 51