Description
Organisers: Carolina Andonie, Vicky Fawcett, Jiachen Jiang, Amy Knight, Amy Rankine, Matthew Temple
AGN are multi-scale phenomena, with interesting physics operating from the event horizon to the circumgalactic medium. In this session, we will bring together research on different aspects of SMBH accretion physics, AGN population studies, and AGN demographics. In this session we will cover:
Accretion discs, jets and outflows in the centers of AGNs. With the recent launch of Xrism and the ongoing success of existing missions, there is a wealth of data from high-energy telescopes. We will accept presentations of observational data analysis, observation-related numerical simulations, and theoretical research for this first session. We also encourage presentations of multi-wavelength and multi-messenger observations.
Obscuration in AGNs from both dust and gas, examining the accretion and host galaxy properties of different AGN populations such as obscured AGNs, red quasars, and HotDOGs. What can these different AGN populations tell us about the SMBH-galaxy connection?
Current and future large-scale surveys such as SDSS, 4MOST, MOONS, WEAVE, DESI, LSST, Euclid and LOFAR. These facilities will produce unprecedented samples of millions of AGN. With the UK taking a leading role in many of these projects, NAM is an excellent opportunity to examine the completeness of our AGN census, and the accretion, galactic and large-scale environmental properties of AGN across luminosity, stellar masses, and cosmic time.
A long-standing issue in X-ray studies of AGN is the nature of the "soft excess", an excess of flux seen below ~2keV when the standard AGN continuum that reproduces high-energy X-ray emission is extrapolated down in energy. One of the leading interpretations is that this feature is related to relativistic reflection from the accretion disc, resulting from a combination of relativistically...
We present a spectroscopic analysis of XMM-Newton and NuSTAR observations of the 'complex' NLS1 PG 1535+547 at redshift $z=0.038$. These observations span three epochs: 2002 and 2006 with XMM-Newton alone, and a coordinated XMM-Newton and NuSTAR observation in 2016, covering the $0.3-70$ keV energy range. The X-ray spectra across all epochs exhibit both neutral and ionized...
Standard accretion disc theory predicts that AGN accretion disc cannot vary on observable time-scales, instead attributing the observed optical/UV variations to the re-processing of X-rays originating from a low-density corona. In recent years the intensive black hole monitoring campaigns (IBRM) have challenged this picture, often showing poor correlations between the optical/UV and X-ray as...
AGN play an important role within their host galaxies, influencing their evolution and growth. Little is known about the initial formation and evolution of AGN in the early Universe. However, new observations by JWST are unveiling larger populations of these sources than previously expected, indicating lower luminosity AGN may be more common in the $z>6$ Universe, when significant galaxy build...
Quasar winds are evident in rest-frame UV spectra in the form of blueshifted broad emission lines. How such winds are launched – and how such launching relates to the physical state of the accretion disc system that powers quasars – remains a key open question. SDSS-V follow-up of eROSITA sources is yielding a large quasar sample for which we have access to their wind properties and (via...
Changing-look active galactic nuclei (CLAGN) are objects that show striking increases or decreases in optical AGN broad line emission over time; e.g., Ricci & Trakhtenbrot, 2023. These events are thought to be mostly the result of dramatic changes in accretion state, and as such provide a laboratory for studying the variation in accretion processes that is known to exist in AGN, but not...
A surprising result from mid-infrared (MIR) interferometry of nearby active galactic nuclei (AGN) is that a major fraction of the parsec-scale dust emission is elongated in the polar direction perpendicular to the accretion plane. This has spurred a new paradigm for the nuclear structure, where a dusty conical wind carries a substantial outflow of material into the interstellar medium. I will...
When we have an unobscured view of the accretion disc, which peaks in the UV, QSOs display very blue UV–optical colours. However, we have recently discovered a hidden population of QSOs, obscured by dust, which are almost completely uncharacterised by previous spectroscopic surveys. These dusty QSOs could represent an important short-lived transitional phase in the evolution of galaxies (a...
Active galactic nuclei (AGN) can have a significant effect on their host galaxies by regulating their growth or suppressing star formation (known as AGN feedback). Of particular importance for massive galaxies and clusters are jet-mode AGN which display powerful radio jets and keep galaxies ‘red and dead’ once quenched. However, until recently, the cosmic evolution of jet-mode AGN has...
AGN activity is often revealed by strong X-ray and radio emission, even when the AGN is obscured at other wavelengths. Some AGN have been observed to be radio bright but X-ray faint, others X-ray bright but radio faint, as well as bright or faint/unobserved in both X-ray and radio. What determines whether the AGN will be X-ray or radio bright? Is it due to one mechanism that determines both,...
Simulations provide a way to connect observations from large-scale surveys of AGN jets to the evolution of these systems. This evolution is closely connected to the accretion process and fuelling physics, which is often variable on a range of timescales. We study this connection by conducting relativistic hydrodynamics (RHD) simulations using the PLUTO code. We use the Lagrangian particle...
Jets from Active Galactic Nuclei have long been observed to interact with the interstellar medium (ISM). Such interactions provide possible mechanisms for star formation quenching, as required by cosmological simulations. The FRII quasar 3CR 14 (z=1.469) has been observed by Chandra to have significant X-ray emission to the southeast of the core, co-aligned with a southeast-northwest...
How AGN (Active Galactic Nuclei) feedback operates is an unsolved mystery plaguing astronomy. AGN outflows could explain how this feedback operates. To investigate this, we use [OIII] as a tracer of ionised outflows. [OIII] has been connected to radio emission and with radio surveys deeper than ever before we can ask: What physical process causes this connection?
A unique instrument which...
Some AGN are known to be efficient producers of strong, relativistic jets which power the extended radio sources. Largest and most powerful are the radio sources associated with AGN hosted by giant elliptical galaxies. Even among them, powerful jets are very rare phenomena and why this is so remains unanswered. Since relativistic jets are likely powered by rotating BHs via the Blandford-Znajek...
A key component of AGN feedback is the injection of kinetic energy from radio jets. However, there’s a fundamental lack of understanding of why quasars, otherwise very similar, have such diverse radio jet powers and, therefore, the impact of AGN jets. Using large samples from LoTSS DR2 coupled with a Bayesian parametric model, we can separate jet from host galaxy radio emission, quantify the...
It is well-established that shocks are the key driver for dust destruction in the interstellar medium (ISM). Feedback process from active galactic nuclei (AGN), such as winds and jets, can generate shocks that create harsh conditions where dust is expected to be destroyed.
Surprisingly, recent JWST observations show that dust grains and polycyclic aromatic hydrocarbons (PAHs) can persist in...
Supermassive black holes (SMBHs) exist in almost all massive galaxies, and accretion of material onto these SMBHs is known to power active galactic nuclei (AGN). In this talk, I will the present results obtained by analysing ALMA data of a diverse sample of 35 nearby galaxies to study the link between circumnuclear (≤100pc) molecular gas reservoirs and AGN fuelling to better understand the...
Galactic feedback processes are thought to regulate the observed co-evolution of accreting black holes and their host galaxy that is observed across cosmic time. Since molecular gas is the fuel for star formation in these galaxies, it is crucial to analyse the molecular ISM properties to understand the impact of AGN/quasars on their host galaxy. Here I will present ALMA CO observations of a...
Co-evolution with active galactic nuclei (AGN) is extensively invoked to explain the properties of massive galaxies and the growth of supermassive black holes. Stellar populations and recent star-formation histories (SFHs), which can help constrain the processes involved in this co-evolution, are challenging to obtain for quasar host galaxies without special decomposition techniques. We use...
Active galactic nuclei (AGN) play a crucial role in the evolution of massive galaxies, but their fueling and feedback efficiency depend on the environment. In this talk, I will present a statistical study of the orientations of AGN jets and their optical counterpart in relation to the cosmic web environment. Using LOFAR Two-metre Sky Survey (LoTSS), DESI Legacy Imaging Surveys, and the SDSS...
Recent JWST observations revealed a surprising number of massive quiescent galaxies (MQGs) at $z>3$. These systems formed and quenched extremely rapidly within the first billion years, which provides new constraints on how ejective AGN feedback can expel large amounts of cold gas from early galaxies.
We will present ultra-deep, spatially resolved JWST/NIRSpec IFU spectroscopy observations...
Measuring the physical properties of AGN and their host galaxies is key to understand their parallel evolution, particularly the correlation between the stellar mass and black hole mass.
Spectral energy distribution (SED) fitting is a powerful tool for extracting the physical properties of galaxies. However, hosting a bright AGN can dilute the host galaxy’s emission, biasing measurements by...
The growth of supermassive black holes and their interaction with their host galaxies still holds many unanswered questions such as the uncertainty surrounding the formation of the first supermassive black holes embedded in first galaxies. The launch of JWST was expected to shed more light on this domain by probing the low mass, low luminosity end of the active galactic nuclei (AGN)...
The James Webb Space Telescope has revealed a large number of galaxies with broad hydrogen/helium lines and bright infrared continua in increasing numbers at $z>4$. Unlike most known Active Galactic Nuclei (AGN), these systems, dubbed "Little Red Dots", lack characteristic X-ray or radio emission, as well as optical variability. Together with frequent Balmer absorption features in them, the...
The characterisation of AGN and their hosts across cosmic time is a key ingredient in understanding galaxy evolution. Acquiring high-quality data is crucial for this, and JWST has generated significant progress in this field. With JWST, AGN identified include those deemed ‘Type-IIs’, which are typically BLR-obscured, with a wealth of inferences still possible through characterisation of their...
There is an evidence for significant evolution in the gaseous and dust properties of galaxies since the era of cosmic noon (z~2). It is also well known that supermassive black holes co-evolve with their host galaxies, suggesting a constant connection between the small-scale (nuclear) and large-scale regions of galaxies. A fundamental component of AGN is the ``torus'' -- a dense, dusty...
AGN feedback has become a key focus of galaxy evolution studies, due to the discovery of quiescent galaxies up to z～7 demonstrating that AGN feedback is required earlier in cosmic time than previously thought. Although JWST has now revealed a larger-than-expected population of AGN at z>4, their influence on their host galaxies’ evolution remains under debate: Does the main impact arise through...
AGN feedback remains a vital path for the quenching of galaxies in theoretical models. With the recent discovery of quiescent galaxies at z>3, identification of typical moderate AGNs at high redshift became more essential than ever, to explain the ever-growing population of quiescent galaxies. As typical selection techniques such as X-ray and radio observations are not sensitive enough to...
A key question in our understanding of super-massive black holes (SMBHs) and active galactic nuclei (AGN) is how they first formed and how they subsequently impacted their hosts. This is one of the objectives of the First Light And Reionisation Epoch Simulations (FLARES), a novel suite of hydrodynamical cosmological zoom simulations. The FLARES strategy allows us to simulate much larger...
Quasars can be classified as red or blue based on their g-i colour. It has been found that the reddest quasars show a significant increase in their radio detection fraction compared to the bluest, and that they appear to be primarily associated with faint, compact radio sources. This makes high-resolution radio observations essential for constraining the physical extent of the radio emission....
Red quasars exhibit a higher incidence of compact (galaxy-scale or smaller) radio emission than blue quasars, arising from systems near the radio-loud/radio-quiet threshold. This result cannot be fully explained by the standard orientation model, instead favouring red quasars as a distinct phase in a quasar’s lifecycle, possibly an obscured-to-unobscured transition where low-power jets and/or...
It is proposed that in many galaxy clusters, the energetic outflows from the active galactic nucleus (AGNs) will balance against the cooling of the diffused, hot gas through a process known as AGN feedback. Yet, in low-mass halos, researchers discovered a systematic entropy excess caused by lower-than-expected gas densities. The excess is commonly attributed to the unbalanced feedback process...
The Dark Energy Spectroscopic Instrument (DESI) survey will provide spectra of millions of quasars and Active Galactic Nuclei (AGN) out to redshifts of 4 and beyond. These will provide both an excellent tracer for large-scale structure at these redshifts and an extraordinary dataset for understanding the impact of AGN on their host galaxies and larger-scale environments enabling a better...
Changing Look AGN show a dramatic transition between UV bright and dim states at around 0.01LEdd, and X-ray selected samples of AGN show that this is ubiquitous, not just restricted to rare objects. This behaviour has many similarities with the soft-hard transition in stellar mass black hole binaries, where it is most easily interpreted as the accretion flow making a transition from a thin...
We describe a machine learning approach to multi-wavelength active galactic nuclei (AGN) identification for host galaxies within the DESI survey. AGNs emit light in all wavelengths in the electromagnetic spectrum, it is difficult to create an AGN selection that is fully complete. The identification of AGNs is key to understanding not only their astrophysics, being an important driver of galaxy...
In recent years, there has been both an expansion in what we know about AGN and central black holes in dwarf galaxies, and a huge deluge of data from JWST about early black holes and galaxy evolution. Our research aims to use the new data about dwarf galaxies to constrain our models of AGN seeding, growth and feedback in GALFORM, the Durham semi-analytic model, and apply this updated model to...
From observations of molecular gas emission and absorption in the cores of clusters and groups of galaxies it is possible to constrain the nature of individual molecular clouds and their distribution from parsec to kiloparsec scales. We will present the analysis of ALMA data for over 20 brightest cluster/group galaxies with strong central continuum sources where absorption from molecules of...
The cosmological distribution of galaxies, particularly active ones, serves as a window into the structure and evolution of the universe, and the processes governing galaxy formation, highlighting the co-evolution of galaxies and SMBHs. Although measuring the distances from the spectral observations can consume precious telescope time, predicting photometrical redshift via machine learning...
Galaxy interactions and mergers have been known to be an important method of triggering central supermassive black holes into active galactic nuclei (AGN). One method to identify these systems is by looking for close pairs of galaxies. To study environmental effects on AGN triggering in dense galaxy environments, we use a catalog of infrared-bright selected AGN along the lines of sight to...
Active Galactic Nuclei (AGNs) play a crucial role in galaxy evolution and cosmic structure formation. This study presents an improved AGN selection method by combining the Euclid Q1 data from the Euclid Deep Field Fornax (EDFF) with deep near-infrared imaging from the VISTA telescope. While Euclid’s Near Infrared Spectrometer and Photometer (NISP) provides high-sensitivity photometry in the Y,...
Observations of massive black holes in the early universe are revolutionising our understanding of galaxy evolution across cosmic time with cutting edge surveys like JADES, CEERS, UNCOVER, RUBIES and many others. Their unprecedented depth has uncovered a population of both type 1 and 2 AGN at high redshifts (out to z~11), through deep NIRSpec MSA spectroscopy. However, standard emission line...
The co-evolution of supermassive black holes (SMBHs) and galaxies can be effectively constrained through sample-based analyses of the galactic correlates of long-term SMBH growth. Relevant correlates include galaxy stellar mass (M$_*$), star formation rate (SFR), and compactness. The sample-averaged SMBH accretion rate (BHAR), which constrains long-term SMBH growth in galaxy populations of...
The Sloan Digital Sky Survey (SDSS) has repeatedly observed the eROSITA Final Equatorial Survey (eFEDS), providing optical spectroscopy for ~12,000 X-ray sources. Motivated by studies linking AGN obscuration to the optical-to-MIR color, r−W2 (Hickox et al. 2007; Andonie et al. 2025, submitted), I have used SDSS spectra to examine how AGN optical properties vary with r−W2 (i.e., obscuration) as...
This thesis explores the properties of galaxy clusters and Active Galactic Nuclei
(AGNs) using newly available data from the eROSITA Final Equatorial Depth survey,
three fields of the Galaxy And Mass Assembly survey (G09, G12, and G15), and the
DESI Legacy survey, focusing on how these properties depend on, or are influenced by
their surrounding galactic environments and X-ray flux levels....
Recent cosmological simulations predict that the coevolution of SMBHs and galaxies predominantly occurs through secular processes in the epochs between mergers. To test this hypothesis, Simmons, Smethurst & Lintott (2017) isolated galaxy merger-free coevolution by observing a sample of 101 disk-dominated "bulgeless" AGN from SDSS, which are assumed to be merger-free since z~2. They showed that...
Active galactic nucleus (AGN) growth in disk-dominated, merger-free galaxies is poorly understood, largely due to the difficulty in disentangling the AGN emission from that of the host galaxy. By carefully separating this emission, we examine the differences between AGN in galaxies hosting a (possibly) merger-grown, classical bulge, and AGN in secularly grown, truly bulgeless disk galaxies. We...
The narrow line Seyfert 1 galaxy IRAS 13224-3809 exhibits rapid, high amplitude X-ray variability. This provides an excellent opportunity to study how the changing flux state affects the energy spectra of AGN and to conduct reverberation mapping of the inner accretion disc. Using archival XMM-Newton data and custom reduction script we split the observations into three distinct flux states with...
High-redshift (z > 5) quasars provide a unique window into the early growth of supermassive black holes, their coevolution with host galaxies, and the evolving ionisation state of the early Universe. However, traditional high-z quasar selection methods, such as colour-based selection, suffer from high false-positive rates and require resource-intensive spectroscopic follow-up. Efficient...
Active Galactic Nuclei (AGN) dramatically impact galaxy evolution through powerful outflows. This study utilizes new 3D hydrodynamical simulations to investigate the interaction between AGN-driven winds and the multiphased interstellar medium (ISM) of an isolated disk galaxy. Employing the moving-mesh code AREPO, we increased the resolution within the cool gas ($T \leq 20000$K) component of...
The majority of observations of Lyα forest in the vicinity of quasars suggest that these quasars have optically/UV bright lifetimes of t_Q~10^5-10^7yr. However, in some cases t_Q≤10^4yr is implied. Such short lifetimes pose a challenge for the growth of supermassive black holes at z≥6. One possibility to alleviate this issue is if the quasars accrete material in episodes and hence their...
The unified model of AGN depicts a system with an accreting supermassive black hole, a thin equatorial accretion disk, an ionised wind in the polar regions, and an equatorial dusty torus. This geometry is invoked to account for the dichotomy of Type 1 and Type 2 AGN through viewing angle alone by obscuration of the torus, and -- while these structures are on scales which were not resolvable...
Blazars are a subclass of radio-loud active galactic nuclei (AGN) with relativistic jets oriented toward the observer. They typically exhibit a flat or rising X-ray spectrum at high redshift, particularly in the hard X-ray band, which, along with their radio loudness, helps confirm their blazar nature. We present a multiwavelength study of SWIFT J0909.0+0358, a blazar candidate at redshift...
Jets from active nuclei may supply the heating which moderates cooling and accretion from the circum-galactic medium. While
steady overpressured jets can drive a circulatory flow, lateral energy transfer rarely exceeds 3 per cent of jet power, after the initial
bow shock has advanced. Here, we explore if pulses in high-pressure jets are capable of sufficient lateral energy transfer into
the...
Observations of the AGN Fairall 9 with NICER and Swift revealed a strong relationship between the flux of the UV continuum and the X-ray soft excess, indicating the presence of a “warm” Comptonized region which may act as a second reprocessor between the “hot” X-ray corona and the accretion disk. This has previously been suggested as an explanation for the weak X-ray/UV correlation observed in...
This study explores the formation and implications of mini-active galactic nucleus (mAGN) discs around intermediate-mass black holes (IMBHs) embedded in gas-rich globular/nuclear clusters (GCs). We examine the parameter space for stable mAGN discs, considering the influence of IMBH mass, disc radius, and gas density on disc stability. The dynamics of stars and black holes within the mAGN disc...
While there is a mounting observational evidence that intermediate mass black holes (IMBHs) may be important in shaping the properties of dwarf galaxies both at high redshifts and in the local Universe, our theoretical understanding of how these IMBHs grow is largely incomplete. To address this issue, we perform high-resolution simulations of an isolated dwarf galaxy harbouring a $10^4M_\odot$...
We present the largest visually selected sample of extended (>60 arcsec) radio-loud active galactic nuclei (RLAGN) to date, based on the LOw-Frequency Array Two-Metre Sky Survey second data release (LoTSS DR2). From the broader LoTSS DR2 dataset with spectroscopic classifications, we construct a subsample of 2828 RLAGN with radio luminosities greater than $10^{23}$ W Hz$^{−1}$ at $z$<0.57....
In this talk we explore the intricate role of both galaxy-intrinsic and environmental factors in triggering radio AGN activity in the local Universe. We investigate the prevalence of radio AGN by combining radio observations from the LOFAR Two-Metre Sky Survey (LoTSS) data release 2 with optical data from the extensively characterised Sloan Digital Sky Survey (SDSS). The large samples allow us...
The structure and evolution of the Intergalactic Medium (IGM) depends on its thermal history and the metagalactic ultra-violet background. QSOs play a crucial role in both of these at redshifts z < 4, and possibly as early as z < 6, as suggested by reports of large numbers of AGN discovered by JWST at z > 5 and in other recent surveys. We show how the structure of the IGM as detected in the...
