I am now 6 months into my PhD at Durham University. So far I would say I am having a great time despite the pandemic. I haven’t seen my supervisor in person since November and haven’t been into my office in that time either but despite this I have been able to get on with my research and attend virtual conferences with experts from all around the world.
In terms of my own personal progress I feel like I am still nowhere near done with all the reading I need to do in order to feel like I can discuss all aspects of Broad Absorption Line Quasars (BALs) with my supervisor and other experts on the subject. However, I do feel like I am growing in confidence and I am close to starting the full writing process for my first paper on the subject. It is especially useful to have fellow people in Durham working on the problem and potentially producing published output alongside me. Increases the value of every weekly meeting!
My work is still currently focussed on what the main contributing factors are towards the appearance of BALs in around 10-40% of quasars. Before the turn of 2021 I spent most of my research time becoming familiar with the LOFAR output and with the LOFAR Two Metre Sky Survey (LoTSS) DR2 catalogue.This generally involved creating general statistical plots for important parameters of quasars to find differences between BALs and their parent sample.
This was certainly worthwhile, good training and also provided a confirmation of many of the results of my supervisor’s previous paper on the subject using the much smaller DR1 catalogue in 2019. I am now pushing to derive some of my own results and use my larger statistical sample to probe the underlying physics of BALs.
In order to discern between orientation and evolution contributions to BAL appearance we need both observational parameters that correspond to age and/or orientation and also a well described model for both which we can that fit to the observed data.
Firstly, how can we probe orientation. Maybe we can use the images of the quasars to measure their inclination angles and hence correlate observed properties such as their Balnicity Index (proxy for the strong of their outflows) with the inclination and hence support or disprove the orientation theory? This is actually much easier said than done. Even with the superb resolution and sensitivity of LOFAR most BALs and quasars in general appear as unresolved blobs in the image and little can be said about their inclination. This is not always the end of the story though as the fraction of unresolved compared to other well matched populations can still give us some information relative to those groups, but overall the problem still remains.
Secondly, for evolution, we can try to investigate the star formation rates of BALs as compared to typical qusars. Or maybe look for increased dust content, which can be linked to star formation, which may suggest that BALs are in an early stage of quasar evolution. Overall, studies that have attempted to find these differences in the past have been largely unsuccessful.