Spectroscopic follow-up is essential for identifying transients, such as supernovae—the explosive deaths of stars—and tidal disruption events, where a star is ripped apart as it falls into a black hole.  These transients allow us to explore the extremes of physics in conditions far too extreme to replicate in a lab.  Therefore, researching these transients is the only means by which we can study such phenomena.

To discover these transients, we use telescopes to observe the night sky every night.  If a supernova occurs, a new source of light will appear, and the image will differ from that of the previous night, allowing us to detect the event. Spectroscopic follow-up is then vital for further research.  A spectrum represents the wavelengths of light from an object and can provide us with a wealth of information about it.  Each element has unique emission and absorption features visible in the spectrum, which astronomers use to classify transients.  For example, all Type I supernovae have no hydrogen in their spectra, whereas Type II supernovae exhibit strong hydrogen lines.

We are fortunate to have excellent facilities that allow us to obtain these spectra and continue our research.  One such facility is the 3.58m New Technology Telescope (NTT) at the European Southern Observatory (ESO) in Chile, which I recently had the incredible opportunity to visit and use.  The Public ESO Spectroscopic Survey of Transient Objects (PESSTO) utilises the NTT to acquire spectra of objects discovered by members of the collaboration.  These members take turns going on ‘runs’ to the observatory to conduct observations, and this February, it was the turn of myself and Dr James Gillanders (University of Oxford).

To reach the observatory, I flew from Belfast to Santiago, with stops in London, São Paulo, and Montevideo, before continuing on to La Serena in northern Chile, which offers some of the most ideal conditions for astronomical observations on the planet.  The dry climate of the Atacama, combined with the high elevation of the Andes, results in low humidity and low airmass, which maximises the signal-to-noise ratio of our observations.  This ensures high-quality data and enhances the science we can conduct with them.

We carried out seven nights of observations over eleven days on the mountain, classifying 36 transients and conducting follow-up observations on many others. Becoming nocturnal was a challenging adjustment, but the stunningly clear night sky made it well worth it.  The surrounding mountain landscape rivalled the beauty of the sky, and encounters with its inhabitants—grazing guanacos, friendly wild donkeys, and soaring condors—further enriched the experience.  The tranquillity and peacefulness of my time at the observatory is something I will never forget.

In addition to having a wonderful time, I also developed key scientific skills while at the observatory.

The most important among these was the ability to create an observing schedule, selecting targets based on their priority, visibility, and position to maximise our use of the telescope.  Furthermore, having now experienced the process of making observations and all the work that goes into operating a telescope, I have a much greater appreciation for the data I work with.

This experience has also been invaluable for my future career, as it has given me direct observing experience and insight into the role of telescope operators.  I now have a far better understanding of the practical challenges of gathering astronomical data and the expertise required to ensure smooth telescope operations.  Gaining this first-hand knowledge will be particularly beneficial in my research, allowing me to better interpret observational data and collaborate more effectively with those involved in data collection.

Additionally, this experience has strengthened the interdisciplinary aspects of my work, as my improved understanding of telescope operations will help me analyse the environmental impacts of astronomical research more effectively and develop stronger policy suggestions to minimise them.

Following our observation run, I had the opportunity to give a talk about my research at the ESO offices in Santiago as part of their seminar series.  This was my second external talk and my first time speaking to an audience outside my field.  As a result, the questions I received were quite different from those at my talk in Oxford, making this a valuable opportunity to develop my skills as a speaker.

Overall, my trip to Chile was an incredibly valuable experience, providing me with essential training in a breathtakingly beautiful and peaceful setting.  I would go back in a heartbeat!

 

Dylan Magill

Dylan Magill is a first year Doctoral Scholar on the LINAS Doctoral Training Programme.  Dylan’s research focuses on developing a machine-learning algorithm to identify tidal disruption events (TDEs), which occur when stars are ripped apart by the intense gravitational forces they experience as they approach supermassive black holes.  TDEs are a relatively recent astronomical discovery with a small catalogue of observations.  They are vital for investigating the properties and feeding conditions of otherwise incredibly difficult to observe black holes.