Ada Lovelace Day 2023

On 10th October, Astro-Obs researchers Carola Zanoletti, Houda Haidar, Beth Gould, and Melissa Ewing organised a watch party for the Royal Institution’s Ada Lovelace Day Live ‘science cabaret’! The annual event celebrates the contributions of women in science, and aims to inspire and empower the next generation of women in STEM.

Students and staff alike gathered in the evening for pizza, before sitting down together to watch the live stream.

As Newcastle’s local committee for Piscopia – an initiative founded to foster participation from women and other under-represented genders in maths and physics – Carola, Houda, Beth, and Melissa aim to put on more EDI events throughout the year, and build a community in the school of Maths, Statistics and Physics!

DEX-XIX: Astro-Obs members present their research at Durham-Edinburgh eXtragalactic workshop

Last week, several members of the Astro-Obs group travelled to the Royal Observatory in Edinburgh for the annual Durham-Edinburgh eXtragalactic workshop. The workshop, which has a strong focus on research into active galactic nuclei and observational cosmology, began as an annual meeting between academics at Durham and Edinburgh. It has since grown to include, Newcastle University, Lancaster University, and the University of St. Andrews.

The workshop provides a great opportunity for early career researchers to present their work, and this year Newcastle had their strongest showing yet, with 10 members of Astro-Obs attending, 4 of whom presented. First year PhD student Houda Haidar gave a 15 minute talk on the black hole population in low-mass galaxies in large scale cosmological simulations (her paper can be found here) and Charlie MacMahon, another first year PhD student, gave a short 3 minute flash talk on a novel method for probing the intrinsic alignment of galaxies.

Astro-Obs members brave the wind for a photo overlooking Edinburgh from the top of the Royal Observatory

Postdoc Vicky Fawcett, who joined us this year following the completion of her PhD at Durham (her thesis can be found here), gave a talk on extremely red quasars in DESI. Vicky also helped in the organisation of the whole event.

Finally, as the penultimate talk of the two day workshop, third year PhD student Alex Gough spoke about their recent paper on dark matter multi-streaming (see here for more details). Many other PhD students also attended, further showcasing the development of Astro-Obs and Newcastle as a place for the study of extragalactic physics. Danielle Leonard also played an important role, chairing one of the sessions to ensure everything ran smoothly and to time!

Astro-Obs Members attend specialised AGN conference in Reykjavik

Several members of the Astro-Obs group at Newcastle University flew to Iceland to attend the conference ‘What Drives the Growth of Black Holes? A Decade of Reflection’ at the end of September. This week-long specialist conference was held in the beautiful Harpa Centre in Reykjavik. Researchers there aimed to address fundamental questions around active galactic nuclei (AGN) and their black holes, such as:

  • How does gas accrete onto black holes from the kpc to sub-pc scales?
  • How do the properties of host galaxies and the larger scale environment affect black hole growth?
  • What fuels the rapid growth of the oldest and most massive black holes?
  • What impact do AGN winds, outflows, and jets have on fuelling the black hole and star formation in the galaxy?
PhD student Sean Dougherty gave a talk on his research into AGN activity in galaxy mergers.

During the week, our group members not only attended, but played a key role in the events taking place. Second year PhD student Sean Dougherty gave a talk on his work in finding enhanced AGN activity in high-redshift galaxy mergers. Final-year PhD student Aishwarya Girdhar presented her work on the impact of multi-phase outflows and low power radio jets on the host galaxies of quasars.

Our new postdoctoral researcher, Dr Vicky Fawcett, spoke on the fundamental differences between red and blue quasars. Dr Tiago Costa, who will be joining us as a NUAcT fellow in August, also gave an excellent overview talk.

Finally, Dr Chris Harrison rounded out the week by leading a discussion on the progress made in understanding AGN feedback over the past decade.

Previously, the event had been cancelled due to the eruption of the Eyjafjallajökull volcano in 2010 and then when the next decade came round in 2020, the covid pandemic once again prevented these researchers from meeting. But finally in 2022 it was worth the wait, and the Newcastle Astro-Obs group were able to attend with an even bigger contingent than would have been present in 2020!

Talk: Why sometimes less is more in Cosmology

Remote Talk: “Cosmology and fundamental physics with one-point statistics” by Cora Uhlemann for the Astro Seminar Series at the Waterloo Centre for Astrophysics (Canada) on Wed, Nov 11, 2020

Over the last decade cosmology has developed into a precision science that is able to determine key properties of our Universe by combining observations and theoretical models. So far a lot of this information comes from the Cosmic Microwave Background (CMB) that provides a snapshot of our Universe when it was only about 380,000 years old. The late-time large-scale structure (LSS) mapped by current and future galaxy surveys can in principle extract much more information by recording a motion picture of how structures form over time.

At early times the physics behind the formation of cosmic structures seen in the CMB is simple and linear. In particular, the distribution of matter is almost Gaussian, meaning that when one picks a random location, one is equally likely to find a region that is slightly more or slightly less dense than the average. A Gaussian distribution of matter is fully characterised by two-point statistics and has a “boring” one-point statistics.

The nonlinear clustering of matter over time changes this picture, because dense regions undergo gravitational collapse that makes them shrink and gain mass at the same time. This leaves a skewed distribution of matter at late times, which is non-Gaussian and has an interesting one-point statistics. We can extract additional cosmological information from this shape to complement two-point statistics and better pin down cosmological parameters.

The matter distribution at high redshift z (early times) almost Gaussian and symmetric around the mean density (rho=1). Gravitational clustering lets initially overdense regions (rho>1) collapse making them smaller and denser. At lower redshift (late times) most of the regions in the universe are underdense.

Talk: Lessons from timing the triple system

This was a lightning talk I gave at the NANOGrav Fall 2020 meeting. Our project to test the Strong Equivalence Principle with PSR J0337+1715 did precision pulsar timing using the same telescopes in the same modes as NANOGrav but we found we needed to analyze the observations differently. So this is a lightning talk to point out some of the things we did differently and spark discussion about why. Most notably we found the polarization calibration procedure inadequate and so we implemented a procedure that fits for the polarization calibration simultaneously with fitting for the pulse arrival time; as a happy side-effect, polarization structure in the pulsar signal helps constrain pulse arrival times. You can read the slides, or the video is below (only the five minutes starting at 0:17 is my talk):