Final Announcement: AGN across continents and cosmic time

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This is the final call for registration of interest to participate in the conference AGN across continents and cosmic time, hosted at Durham and Newcastle University. The conference is limited to 80 people and you must register your interest by 30 Nov to be considered for participation. Visit: www.agnacrosscontinents.org

This scientific workshop will explore current understanding of AGN populations, with a particular focus on current and future observational surveys. The primary scientific questions to be addressed are:

  1. How can we establish a complete census of black hole growth across cosmic time (including the highest redshift AGN) and what does this tell us about how and when supermassive black holes form and grow?
  2. What can multi-wavelength surveys tell us about different physical components of AGN and what implications does this have for a standard/unified model or evolutionary model of AGN?
  3. What are the properties of the host galaxies of different AGN populations and what does this tell us about how galaxies and AGN influence each other? 
  4. What are the different data, observational techniques, and analysis methods we need to accelerate progress in answering these questions over the coming decade?

The scope of this workshop covers observational and theoretical work across the full wavelength range that tackle these scientific questions. We anticipate a strong showcase of work that is of strong interest to both the European and African communities. For example, results from SKA pathfinder telescopes such as LOFAR, e-MERLIN, JVLA, and MeerKAT, in addition to telescopes such SALT in South Africa and H.E.S.S. in Namibia. Whilst the focus is on European-African collaboration, scientists from everywhere are welcome to participate.

Confirmed invited speakers: Marie Korsaga; Anna Scaife; Ryan Hickox; Sthabile Kolwa

The workshop will be limited to around 80 participants. Presentation selection will be based on the quality of abstract submissions for talks or posters, and/or their alignment to the focus of the meeting. We will also consider demographics to ensure participation from a wide range of applicants. 

Application Form (participation, abstract submission and for financial support):
You MUST fill out this form to be considered for attendance.
https://www.agnacrosscontinents.org/attendance-application-form 

Deadline: 30th November 2023 
Workshop Dates: 8th – 12th July 2024 
Location: Durham University & Newcastle University (United Kingdom)
Website: www.agnacrosscontinents.org 

Costs and Financial Support

The anticipated conference fee is around £300 (details to be confirmed later). We have a substantial (but finite) budget to support scientists coming to the workshop, with a priority to those from Africa and those who do not have their own funds. This could cover, up to and including all travel and accommodation costs, plus registration fee waiver. Preference for financial support will be given to those most in need, and to early career researchers. Applicants should indicate in their form, the level of financial support they would require to attend the workshop (e.g., travel, accommodation, fee waiver, complete costs, etc.). 

Applications (deadline 30th November)

The mandatory form is to be completed by anybody interested in attending the workshop AGN Across Continents in Durham in July 2024 (even if not submitting an abstract). This form will be used by the Scientific Organising Committee to select participants. It will also be used as an application for any requests for financial support to attend the workshop (details below). Applications for financial support are required at this stage, to ensure we can distribute the limited funds in the most effective and fair way. For more practical information, including options for financial support and key dates, please visit the website: www.agnacrosscontinents.org.

Two new papers: How do powerful supermassive black holes impact upon molecular gas?

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Two new papers have been published from the Quasar Feedback Survey, which is a project led by Chris Harrison. The two papers, led by PhD Students Aishwarya Girdhar and Stephen Molyneux, use data from the ALMA and APEX facilities to establish how rapidly growing supermassive black holes (which we call quasars) are able to influence the molecular gas in their host galaxies. Emission lines associated with Carbon Monoxide (CO) are used to trace the molecular gas.

In the study of Girdhar et al., four quasars are selected from the survey to map in lots of detail, the distribution and motions of the molecular gas. These quasars were selected because they are known to have large bubbles of radio emission extending well beyond the main host galaxy disks. These are thought to be inflated by radio jets expanding from the central black hole. Molecular gas appears to be being lifted by these expanding radio bubbles in two of the targets investigated (see upper panels in the figure). This may be making it more difficult for the galaxy to form stars in the future (molecular gas is the fuel for forming new stars). In all four targets, another impact of the powerful, growing black holes was revealed: extreme velocities were observed close to the central regions (see lower panels in the figure), likely due to “outflowing” gas driven by the jets or powerful radiation in these regions.

In the study of Molyneux et al., 17 quasars were studies from the survey. Using information of multiple different CO emission lines (this time with no spatial information), it was investigated if the molecular gas across the whole galaxies is “excited” due to the powerful quasars and jets in these systems. In short, the conditions of the molecular gas were found to be consistent with that expected if there was no additional excitation (beyond what is typically expected for these sort of highly star-forming host galaxies). The conclusion of these two studies, is that the impact of the quasars is not to instantly affect the whole gas reservoir, but instead, more localised and longer term affects (driving outflows, lifting the gas) may make it more difficult for the host galaxies to form stars in the future. This is consistent with expectations from theoretical models and simulations, as recently demonstrated by another one of our PhD students, Samuel Ward, in Ward et al. (2022).

Ada Lovelace Day 2023

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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!

Hidden supermassive black holes reveal their secrets through radio signals

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An artist’s impression of a red quasar. Red quasars are enshrouded by gas and dust, which may get blown away by outflows from the supermassive black hole, eventually revealing a typical blue quasar.
Credit: S. Munro & L. Klindt, Licence: Attribution (CC BY 4.0)

A team of international astronomers, led by Newcastle University, have used new data from the Dark Energy Spectroscopic Instrument (DESI), which is conducting a five year survey of large scale structure in the universe that will include optical spectra for ~3 million quasars; extremely bright galaxies powered by supermassive black holes. They found that quasars that contained more dust, and therefore appeared redder, were more likely to have stronger radio emission compared to the quasars that had very little-to-no dust, appearing very blue.

Photograph of the Mayall Telescope, which hosts the Dark Energy Spectroscopic Instrument, at Kitt Peak National Observatory. Credit: Marilyn Sargent, photographer. Copyright: © 2018 The Regents of the University of California, Lawrence Berkeley National Laboratory

Almost every known galaxy contains a supermassive black hole, which are black holes with a mass millions to billions that of our Sun, at its centre, including our own Milky Way. In some galaxies there is lots of material in the centre, feeding and growing this supermassive black hole, making it very energetic and “active”. The most powerful type of these active galaxies are called “quasars”, which are some of the brightest objects in the Universe. Most quasars appear very blue, due to the bright disc of matter that orbits and feeds the central supermassive black hole which is very bright in optical and ultraviolet wavelengths. However, astronomers have found that a significant fraction of these quasars appear very red, although the nature of these objects is still not well understood.

In order to understand the physics of these red quasars, “spectroscopic” measurements are required, which can be used to analyse the quasar light at different wavelengths. The “shape” of the quasar’s spectrum can indicate the amount of dust present surrounding the central region. Observing the radio emission from quasars can also tell you about the energetics of the central supermassive black hole; whether it is launching powerful “winds” or “jets” that might shape the surrounding galaxy.

Images of DESI quasars, going from blue (typical) quasars on the left to the red quasars on the right, taken from the Legacy Survey Viewer. The redder quasars are more likely to have strong radio emission compared to the bluer quasars. Credit: V. Fawcett, using images from https://www.legacysurvey.org/viewer

This new study, led by Dr Victoria Fawcett of Newcastle University, and previously Durham University, uses spectroscopic observations from DESI to measure the amount of dust (reddening) in a sample of ~35,000 quasars and link this to the observed radio emission. They find that DESI is capable of observing much more extreme red (dusty) quasars compared to similar/previous spectroscopic surveys, such as the Sloan Digital Sky Survey (SDSS). They also find that redder quasars are much more likely to have strong radio emission compared to typical blue quasars (see link to movie at the end of the article).

This reddening-radio connection is likely due to powerful outflows of gas driven away from the supermassive black hole, which slam into the surrounding dust, causing shocks and radio emission. These outflows will eventually blow away all the dust and gas in the central region of the galaxy, revealing a blue quasar and resulting in weaker radio emission. This is consistent with the emerging picture that red quasars are a younger, “blow-out” phase in the evolution of galaxies. Red quasars may therefore be extremely important for understanding how galaxies evolve over time.

Paper: https://academic.oup.com/mnras/article/525/4/5575/7273139?login=true

Helping more girls complete basic education in Kenya

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Copy of DSC_0642
Photo credit: Dr Ann Njeri

Dr Ann Njeri’s recent press release article discusses the issue of keeping Kenyan girls in education and what can and is being done to help address it. Statistics shared by Dr Njeri in her article paint a clear motivation behind the importance of tackling this problem, such as the fact that only 18% of Kenyan women aged over 25 have completed secondary education. Fortunately, the Elimisha Msichana, Elimisha Jamii (EMEJA) foundation, founded by Dr Njeri, is working to solve this issue, by tackling contributing problems such as misconceptions about STEM among young schoolgirls, through the hosting of Astro-STEM workshops and mentorship programmes, as well as much more. However, as Dr Njeri points out, more help and deeper institutional change is needed to fully solve this problem. To find out more about what is causing low academic retention among Kenyan schoolgirls, the work of EMEJA, and what more can be done to help, see her full article linked below.

https://from.ncl.ac.uk/helping-more-girls-complete-basic-education-in-kenya

Paper: Testing a Novel Approach to Measuring the Intrinsic Alignment of Galaxies

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Charlie MacMahon has just submitted his first paper as first author for publication, and it is already available as a pre-print on the arXiv! In it, he and his supervisor Danielle Leonard investigate a novel method for measuring intrinsic alignment.

A simplistic diagram showing how intrinsic alignment influences our measurements of galaxy shape and why this affects weak lensing measurements.

Intrinsic alignment refers to a phenomenon in which galaxies near to each other will align with local, large-scale gravitational fields in a way that causes their shapes to become statistically correlated. These correlations can bias weak lensing measurements, but are themselves also interesting tracers of galaxy evolution and underlying cosmology.

Taking the difference of the shape estimates at the two different measurement scales allows us to recover the difference in the intrinsic alignment signal.

Charlie’s paper looks at measuring intrinsic alignment using two different estimators of galaxy shape, which are individually sensitive to different parts of galaxies, because it’s expected that the outer regions of a galaxy should be more aligned with local fields than the inner regions. This method allows a portion of the intrinsic alignment signal to be recovered in a way that is more robust to uncertainty in galaxy redshift than other methods.

In the paper, the method is applied for the first time to real galaxy shape data from the Dark Energy Survey Year 1, and various assumptions of the method are tested to help develop a framework of necessary considerations and steps for using this method. The paper shows the difficulty of working with observational data and the importance of rigorous testing for contamination and systematics.

Constraining power of the method for different combinations of shape estimator parameters, when fitting a model of intrinsic alignment to mock Rubin Observatory data.

Taking what is learnt from this first application to data, forecasts are conducted using a mock catalogue of Rubin Observatory data (part of the next generation of lensing surveys) and a contemporary model for intrinsic alignment. With this data, the performance of the method is evaluated in various contexts, and requirements are then placed on the shape estimators to ensure robustness to systematics and a strong measurement are achieved. Overall, the paper proposes a clear path for the continued development of the method, and demonstrates promise for its use with future Rubin Observatory data.

Hidden supermassive black holes brought to life by galaxies on collision course

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A new study, led by Sean Dougherty who carried out this work whilst an MPhil student in our group, was publicly released today. The study found that supermassive black holes obscured by dust are more likely to grow and release tremendous amounts of energy, when they are inside galaxies that are expected to collide with a neighbouring galaxy. It is published in Monthly Notices of the Royal Astronomical Society and is available on the arXiv. 

A press release was produced to celebrate the results, shared by both the Royal Astronomical Society and Newcastle University. 

This study presents a new statistical method to overcome the previous limitations of measuring accurate distances of galaxies and supermassive black holes. It applies a statistical approach to determine galaxy distances using images at different wavelengths (i.e., ‘photometric redshifts’) and removes the need for spectroscopic distance measurements for individual galaxies, which are only available for a small fraction of galaxies.

They applied this new method to hundreds of thousands of galaxies in the distant universe (looking at galaxies formed 2 to 6 billion years after the Big Bang) to better understand the so-called ‘cosmic noon’, a time when most of the Universe’s galaxy and black hole growth is expected to have taken place.

Using this new method, Sean investigated the number of growing supermassive black holes (called active galactic nuclei), in galaxies which are in close pairs with other galaxies.  This was compared to the number found in galaxies without close pairs i.e., ‘isolated’ galaxies.  In agreement with previous work, it is found that the fraction of galaxies containing active galactic nuclei identified with X-rays is the same for both galaxy pairs and isolated galaxies. However, those which are hidden in the X-rays due to obscuring dust, and are only seen in infrared light, are twice as common in the close galaxy pairs.  

The excess (or ‘enhancement’) of obscured active galactic nuclei (growing super massive black hole) found in galaxy pairs, compared to isolated galaxies, as a function of separation to another galaxy. The results show that there is a boost in the number by a factor of ~2 for the closest galaxy pairs.

The difficulty in finding these black holes and in establishing precise distance measurements explains why this result has previously been challenging to pin down for these distant `cosmic noon’ galaxies.  

The expectation is that these close galaxy pairs are on the route to colliding, and eventually merging. This process helps drive gas down onto the black holes. On its journey this gas releases a tremendous amount of energy and heats up the surrounding dust, which glows in the infrared.

Astro-Obs PhD student organises black hole science demonstration for refugee children

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Last week, PhD student Houda Haidar and Native Scientist coordinator Hania Tayara, partnered to organise an astronomy demonstration for Arabic-speaking refugee and asylum-seeking children. The demo was part of a broader scientific workshop that was held at Newman Catholic College in London. Houda’s demo focused on black hole physics and included three main activities.

The first activity helped the children understand the concept of density. This was demonstrated using a golf ball and a larger foam ball, to show that the biggest objects are not always the ones with the most mass.

Houda participates in these three activities with the children, to teach them important concepts for black hole physics.

The second activity involved understanding space-time curvature. The golf ball and the foam ball were dropped on a scarf, which represented the “fabric” of space-time. The children could then observe which object led to deeper curvatures in the scarf.

The third activity involved understanding how accreting black holes obscured by dusty materials can be detected using a mid-infrared camera. Houda used a black bag to represent the dusty torus of accretion material, which can obscure accreting black holes. Despite the black bag preventing Houda from being seen by human eyes (or a camera in the optical wavelengths), with an infrared camera, Houda could be seen behind the black bag.

A fun and simple model Houda made to help teach the children about active galactic nuclei. It includes a dusty torus, an accretion disc, and even jets!

Other scientists from different disciplines (e.g., medicine, biology) also presented engaging demonstrations and tutorials. These ranged from extracting DNA from a strawberry to recording signals from the brain. 

Celebrating the History of Astronomy and Telescopes in North East England

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In January 2023, Dr Vicky Fawcett and Dr Chris Harrison won a ~£14K STFC Spark Award [1] to put towards a project celebrating the history of astronomy and telescopes in the North East of England. The award, along with contributions from both Newcastle University and the Great North Museum: Hancock (GNM), will be primarily used to develop a six month exhibition, hosted by the GNM in 2024.

The museum exhibition will showcase the rich history of astronomy in the North East, from the 1800’s when Gateshead was home to the largest telescope in the world (the Newall Telescope) to the 20th century, when Grubb Parsons of Newcastle manufactured many important telescopes that continue to perform cutting edge science today. The exhibition will also highlight the ongoing state-of-the-art astronomical research carried out in the region, such as the projects involving the James Webb Space Telescope (JWST) and Extremely Large Telescope (ELT). Despite the strong link between astronomy and the local area, the extent of impact that the North East of England has had on the progression of astronomy is relatively unknown. The exhibition will therefore aim to raise awareness of astronomy and telescope engineering in the North East and instil a sense of pride in the STEM successes of the region. The exhibition will also be designed to ensure that a large portion of objects and artefacts will be transportable, with the aim to host similar smaller-scale exhibitions at other venues across the region.

Via Photographs of Newcastle: “Construction of the Stockholm 40″ Reflector, some time in the early 1920’s for the Stockholm Observatory.
Photograph courtesy of Tyne & Wear Archives & Museums.“

One key objective of the project is to inspire young people in the region to engage more with STEM and raise awareness of STEM-related careers (with a particular emphasis on schools based in areas of low socio-economic background). This is especially important in the North East, which has the lowest percentage of young people in the UK who say a career in science would interest them [2]. The project aims to address this issue by running a series of educational workshops alongside the museum exhibition, that will deliver the Key Stage 2 & 3 science curriculum in a more relatable and engaging way. These workshops will be delivered by Newcastle University and project partners: the GNM, Kielder Observatory and Durham University. Finally, a key aspect of the project will involve teacher training sessions, in order to equip teachers with the confidence and knowledge needed to deliver the astronomy workshops at school beyond the end date of the project.

[1] https://www.ukri.org/opportunity/engage-the-public-with-science-technology-or-facilities-spark-awards-2022-round-two/
[2] https://www.britishscienceassociation.org/news/regional-differences-in-young-peoples-aspirations-and-interests-in-science

International Women’s Day 2023

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Happy International Women’s Day! On this special day, Astro-Obs/Cosmo women organised a fun yet relaxed gathering, where MSP students & staff came together to recognise the outstanding achievements of women, and how they continue to carve out a place for them in science.

The event was held in the Herschel Penthouse, where attendees were welcomed with tea & cake.

Astro-Obs students colouring together while enjoying tea and coffee.

Colouring sheets featuring various female scientists (e.g., Ada Lovelace, Jocelyn Bell Burnell, Mae Jemison, Florence Nightingale) and space (e.g., astronauts, exoplanets, galaxies) were provided, creating an outlet for people to express themselves and unleash their inner artists. Some were lost in their thoughts as they coloured, while others shared stories about their lives and the women that inspired them. The atmosphere was very friendly and engaging, with everyone praising each other’s colouring skills. 

Exoplanet travel poster colouring sheet.

It was amazing to see how a simple activity like colouring can bring a sense of togetherness and solidarity. 

Lots of MSP students and staff sat together taking some time to relax and celebrate International Women’s Day together!

Fan fact: When asked to name a female role model, the most common answer was ‘’Mum’’. Who’s your female role model?

People sharing the names of the women who are an inspiration to them.