A full publication list (NASA ADS) here or in a PDF here.

Select Publications

Below are a few select publications with short explanations and figures from the published paper.

Efficacy of urodynamic studies in predicting long-term outcomes of the transobturator tape: do they augment clinical assessment? [Cent European J Urol . 2019]

Authors:Croghan, S. M.; Costigan, G ; O'Dwyer, N; MacCraith, E.; Lennon, G;

Some controversy exists regarding necessity for urodynamic evaluation prior to surgical management of stress urinary incontinence (SUI). We aimed to interrogate the role of pre and post-operative urodynamic studies versus clinical assessment in predicting long-term patient reported outcomes of transobturator tape (TOT) placement.

Halpha time series during eclipse.
Time-series of the Hα emission of RW Aur after the start of the dimming event. (Fig. 5 in paper). This emission demonstrates that the star is a strong accretor (i.e. still growing in mass), and weaker blue shifter emission then was observed before the dimming event.

The disappearing act: A dusty wind eclipsing RW Aur [MNRAS 2016]

Authors: Bozhinova, I; Scholz, A.; Costigan,G; Lux, O.; Davis, C. J.; Ray, T.; Boardman, N. F.; Hay, K. L.; Hewlett, T.; Hodosan, G.; Morton. Reference: MNRAS 463, 4,pp. 4459-4468.

RW Aur is an interesting young star that has seen much attention recently due to some enigmatic activity. We used both photometric and spectroscopic observations taken before and during the large dimming event in 2015 to investigate it's cause.

My role in this project was to analyse the IFU observations taken with FRODOSpec. The python code used to reduce and analyse the data can be found here. Fig. 1 shows a plot I made from these data showing the changes observed in the Hα line during the dimming event.

Pre- and Post-burst Radio Observations of the Class 0 Protostar HOPS 383 in Orion [ApJL 2015]

Authors: Galvan-Madrid,R.; Rodriguez, L. F.; Liu, H.; Costigan,G; Palau,A; Zapata, L. A.; Loinard, L. (APJL 2016, 806, 2, L32, 5)

A large infrared outburst was observed Hops 383 between 2004 and 2008, which was associated with a huge increase infalling mass onto the central star. These accretion bursts are thought to be closely related with changes in the jet emission. However, we analysed archival VLA observations which showed now large variations in emission over this time period. Suggesting these two phenomenon are not as tightly correlated as previously thought.

Luminosity to Accretion rate fit.
Accretion luminosity versus Hα line luminosity (Same emission line as seen above). The solid black line indicates the fit to both data sets and the shaded grey region indicates the 2-σ confidence interval around this fit. See paper for full explanation.

Temperaments of young stars: Rapid mass-accretion rate changes in TTauri and Herbig Ae stars [MNRAS 2014]

Authors: Costigan,G., Vink, J., Scholz, A., Ray, T., Testi, L. (MNRAS 440, 4, 3444-3461)

With observations of 15 young active stars (TTauri and Herbig Ae stars) we investigated variations on short timescales, minutes, hours, weeks, up to longer timescales of years. To do this we used an emission line closely associated with accretion, Hα (see Fig. 1 for example profile)

In order to perform a uniform analysis over the entire sample (which spanned a large mass range 0.1 to 5 solar masses) we fitted observed accretion luminosities and line luminosities for a number of different data sets. This allowed us to derive a new relation which we then used for the entire sample. This fit can be seen to the right in Fig. 2. The code used to create this figure can be found here

Variations in accretion rates versus timescales.
Magnitude of variations in accretion rates versus timescales over which they are observed. This plot includes data from a number different data sets. Here the error bars indicate the range in values for each data point. Original plot from Costigan et. al 2014.

LAMP: the long-term accretion monitoring programme of T Tauri stars in Chamaeleon I [MNRAS 2013]

Authors: Costigan,G., Scholz, A. Stelzer, B, Ray, T., Vnik, J., Mohanty, S. MNRAS 427, 2, 1344-1362.

Variability studies often target variable stars, so many of them do not give a true picture of a 'normal variability'. This study specifically set out to study a unbiased sample of young stellar objects in the Chameleon region.

Fig. 3 shows this study put in context with other variable studies (which used similar activity traces i.e. optical emission lines associated with accretion). Together all of these works suggest that variations occur on timescales close to the rotation periods of these stars. This is a likely situation as these systems are often not axially symmetric and so any rotation will change the viewing angle of the mass flows onto the surface of the star.