Ecogia Science Meetings
Unige science meetings
Ecogia Science Meetings 2020-2021
Schedule
Meetings are at 14 in the Pavillon meeting room at Ecogia
2020-09-07 Dominique Eckert ** Dark matter distribution in galaxy clusters
In spite of more than 40 years of active research on the topic, the nature of dark matter remains one of the most pressing questions of modern physics. While none of the attempts of direct and indirect detection has yet been fruitful, clues on the origin of dark matter can be obtained by studying the properties of the gravitational field in astrophysical objects. As the most massive collapsed structures in the Universe, galaxy clusters are privileged sites to study the dark matter distribution. In particular, the current cosmological paradigm predicts that dark matter halos should follow a Universal shape. Potential deviations from the predicted shape could provide important insights into the nature of dark matter. In this talk, I will present recent high-quality measurements of the dark matter distribution in nearby galaxy clusters from the combination of X-ray data with measurements of the Sunyaev-Zeldovich effect. I will explain how the reconstructed dark matter profiles can be used to give some possible clues on the properties of dark matter.
2020-09-14 Vitalii Sliusar ** On the progress of Cherenkov Telescope Array construction
Cherenkov Telescope Array (CTA) is one of the primary ground-basedvery-high-energy astrophysics projects sensitive from 20 GeV to 300TeV. It will consist of 118 telescopes located on two sites: Northern(La Palma, Canary Islands) and South (Paranal, Chile). I will describethe most recent development in the construction of CTA, particularly theLarge-Size Telescope 1 (LST-1), located at the CTA Northern site. I willspeak about the technical challenges of telescope control, scheduling,and orchestration of its numerous subsystems in their connection to thescientific objectives of CTA. I will summarize my contribution to CTAand future plans.
2020-09-21 Volodymyr Savchenko ** Impulsive gamma-ray events and extra-galactic magnetars
I will discuss how magnetars, one of the most exotic objects known, although still lacking conclusive proof of existence, have gradually settled over much of the domain of short and energetic transients, both in and out of our galaxy. And how INTEGRAL observations managed to contribute considerably to this process.
2020-09-28 Isabelle Santos ** Combining template fitting and machine learning
To perform weak lensing -- one of the science goals of the Euclidmission -- high accuracy redshifts for a large number of galaxiesare needed. Two broad families of methods exist to estimatephotometric redshift (photo-z), each with their pros and cons:machine learning (ML) methods which rely on training with availablespectroscopic data, and template fitting (TF) which rely on models,or templates, provided by the user. Machine learning methods performwell in the part of the parameter space where many training samplesare available. However, they lack the ability to extrapolate to newdata. Template fitting performs better on high redshift samples forwhich little training data is available. Yet they are dependent ofthe galactic models provided by the user, which may fail to containall the information that can be extracted by training an ML model onrepresentative data. I present avenues of research to combinetemplate fitting and machine learning techniques, to yield betterphotometric redshift estimates.
2020-10-05 Carlo Ferrigno ** A pedagogical view at the NICER Constraints on the Dense Matter Equation of State
Thermal emission in soft X-rays emanating from the surfaces of nearby neutron stars (NSs) offers a window into the interior composition, including the still-uncertain physics of the ultra-dense matter in their cores. With several megaseconds of exposure across a handful of rotation powered, millisecond-period pulsars (MSPs), NASA's Neutron star Interior Composition Explorer (NICER) has accumulated a unique data set with which the mission's Science Team and collaborators are pursuing key insights into the properties of the targeted NSs.In late 2019, a series of papers appeared with cutting-edge results on the modeling of the pulsar PSR J0030+0451, a nearby (325 pc) and rapidly rotating (4.87 ms period) pulsar. They Bayesian modelling of its energy-dependent pulse profiles provided the first determination of mass and radius for the same star, the first mass determination for an isolated NS, the first complete relativistic modeling of the surface emission.I will show methods and results of this extraordinary achievement.
2020-10-12 Jakub Jurysek ** Performance of the CTA prototypes in mono regime and atmospheric monitoring
The Cherenkov Telescope Array (CTA) is a next-generation ground-based VHE gamma-ray observatory, currently in preparation. I will present the Monte Carlo study of two prototypes of telescopes for the CTA observatory, followed by the first data analysis. Using precise Monte Carlo models, we evaluated the performance of the SST-1M and LST-1 prototypes, working so-far in mono-regime as standalone telescopes, resulting in their energy and angular resolution, and the differential sensitivity. I will also present an analysis of the data from the first two Crab Nebula observation campaigns conducted with the LST-1 telescope. In the second part of the talk, I will present a study of aerosol optical depth of the atmosphere above both future sites of the CTA observatory, retrieved from photometric measurements of Sun/Moon photometers. I will focus on the photometer in-situ calibration for nocturnal measurements, and on corrections, which we introduced to minimize systematic shifts between diurnal and nocturnal measurements. Using the developed methods, I will present the first preliminary aerosol characterization of both CTA sites based on the photometric data.
2020-10-19 Marc Audard ** Deep X-ray view of a young embedded star: a preview of science with XRISM/ATHENA
I will report on a paper made by Pillitteri et al. (2019), A&A, 623,A67 who observed the youngembedded young star Elias 29 withXMM-Newton and NuSTAR. Their observations are key tounderstand thepresence of X-ray emission in very young, forming stars, and tounderstand theorigin and impact of such X-rays on the circumstellarmatter. I will extend the presentation toscience that can be done inthis field with XRISM/Resolve and ATHENA/X-IFU.
2020-10-26 Andrea Tramacere ** Multiwavelength modeling of the microquasar MAXI J1820+070 during the 2018 outburst, with the JeSeT framework
I will present a self-consistent leptonic model of the multiwavelength SED of MAXI J1820+070from radio to hard-X-ray frequencies, during the 2018 outburst, based on the JetSeT framework.I will discuss the jet magnetic field topology and how it possible to constrain the positionof the acceleration region based on the spectral properties of the flat-radio spectrum observed in the data.I will show that a compact acceleration region the feed an extended radio jet, with theinclusion of the radiative cooling, can explain the optical to radio data, and can reproducenaturally the flat radio spectrum. I will show also that an irradiated disk plus Comptonizingcorona can explain the UV up to hard-X-ray data.
2020-11-02 Marco Tucci ** Modelling radio luminosity functions of radio–loud AGN by thecosmological evolution of supermassive black holes.
Active Galactic Nuclei (AGN) have been of particular interest over thepast decade due to the crucial role they play in galaxy formation andevolution. They are associated with the accretion of material onsupermassive black holes (SMBHs), with masses that vary from millionsto billions solar masses.In this presentation I will describe a formalism to model theluminosity function of radio-loud AGN at GHz frequencies by thecosmological evolution of SMBHs (in terms of mass function andEddington ratio distribution), and based on physical andphenomenological relations. The Fundamental Plane of black holeactivity is used to statistically calculate the radio luminosity ofAGN jet cores. Moreover, radio luminosity from extended jets and lobesis also computed through a power-law relationship that reflects theexpected correlation between the inner radio core and the extendedjets/lobes.By following a well established classification scheme, radio-loud AGNare divided in two classes, characterized by the different accretionmodes onto the central BH, i.e. low-accreting (or jet-mode) andhigh-accreting (or radiative-mode) AGN. The few free parameters usedin the model are determined by fitting two different types ofobservational data sets: local (or low redshift) LFs of radio-loud AGNat 1.4 GHz and differential number counts at GHz frequencies. In thepresentation I will show model results, in comparison with theavailable observational data.
2020-11-09 Lingsong Ge ** Bayesian analysis of AGN X-ray spectral and population inference
In this talk I will present updates of my work about the X-ray spectral analysis of Active Galactic Nuclei (AGSs) using a physically-motivated Bayesian model, and population inference based on redistribution of stacked probability density functions (PDFs). Main difficulties of the characterization of AGN X-ray spectral properties and their populations are the complexity of the X-ray emissions and low quality of data in a survey with medium-low sensitivity. Source components like reflection and soft-excess, are present in the X-ray spectra of AGNs, but they are not necessarily detectable when S/N is low. The classic way of dealing with this difficulty is to use different models with different complexity to fit different types of spectra. However, this approach tends to adopt a model which is too simple, introducing biases and giving unrealistic error in recovering the main parameters, e.g. hydrogen column density (nH) and photon index. I will present the comparison of fitting a realistic simulated sample with both the classic method and our Bayesian method, and an updated result of the application to the XMM-COSMOS sample, for which we made new simulations to build more accurate redistribution matrices.
2020-11-16 Nicolas Produit ** Eventually understanding intensity interferometry.
I will speak about my struggle to try to understand why intensity interferometry is working.You will get answer to difficult questions like:-what is coherent light?-why intensity interferometry is NOT working for coherent light.
2020-11-23 Guillaume Desprez ** Galactic conformity in galaxies clusters and groups
Most galaxies can be separated into two groups : they are either disc and actively star-forming galaxies (blue) or spheroidal galaxies with little or no star formation (red). When looking at the properties of galaxies in groups, a correlation between the characteristics of the central galaxies and its satellites is observed, with the fraction of red satellites being higher in groups with red centrals. This phenomenon was first observed by Weinmann et al. (2006) and is now known in the literature as “galactic conformity”. In the view of a future study on galactic conformity with the HSC-CLAUDS surveys data, I will review what do we know of the phenomenon since its discovery.
2020-11-30 William Hartley ** The Facebook of the Cosmos
Galaxy surveys designed for weak lensing cosmology must be both wide and deep in order to contain enough galaxies for precise cosmology measurements. As a result, they are conducted in as few photometric bands as the analysis can get away with, leading to rather little information per object. Deep survey fields that have rich data sets built up for galaxy evolution analysis are frequently used to supplement a WL survey, and their use has grown increasingly sophisticated over time. I will tell the brief story of how deep fields have been used in WL cosmology over the last two decades, and then describe the most recent DES incarnation for our almost-completed 3-year analysis.
2020-12-07 Lionel Metrallier ** ClearSpace: The Swiss start-up to remove space debris.
In the past years, discussions about space debris hazards have drastically increased, following in orbit break-ups, collisions, and the arrival of large constellations in low earth orbit. The fear of the Kessler effect is unanimously invading the space community. In response to this worrying situation, private companies and national/international agencies are currently developing concepts and bringing new ideas on how to tackle this problem.The European Space Agency has recently signed a contract with ClearSpace SA, a young start-up based in Lausanne, to perform an active debris removal and in-orbit servicing technology demonstration mission.Throughout this talk, I will present the problem of space debris and the ambition of ClearSpace SA in this context. I will mainly focus on the first mission, ClearSpace-1, set to be launched in 2025. ClearSpace-1 is a ground-breaking and very ambitious mission aiming at capturing and removing from orbit an uncooperative space debris for the first time in history.
2021-02-01 Celine Armand ** Gamma-ray image reconstruction of Andromeda galaxy (M31)
Andromeda galaxy (M31) represents our nearest large neighbor spiral galaxy with a distance of 785 kpc. Its close proximity allows us to optically resolve its stellar disk and bulge as two separate components. Although M31 spans 3.2º x 1º on the sky in optical light, the determination of its extension in γ rays remains controversial. We analyze about 12 years of Fermi-LAT data using the code skyFACT which combines template fitting and image reconstruction. In this work, we robustly characterize its spectral and morphological properties against systematic uncertainties related to the modeling of the Galactic diffuse emission. We present for the first time a proper comparison of non-nested models describing M31 morphology and show the reconstruction of its γ-ray image in a template-independent way in order to identify its components.
2021-02-08 Isabelle Santos ** Amalgamating photometric redshifts from template fitting and machine learning
To perform weak lensing -- one of the science goals of the Euclidmission -- high accuracy redshifts for a large number of galaxiesare needed. Two broad families of methods exist to estimatephotometric redshift (photo-z), each with their pros and cons:machine learning (ML) methods which rely on training with availablespectroscopic data, and template fitting (TF) which rely on models,or templates, provided by the user. Machine learning methods performwell in the part of the parameter space where many training samplesare available. However, they lack the ability to extrapolate to newdata. Template fitting performs better on high redshift samples forwhich little training data is available. Yet they are dependent ofthe galactic models provided by the user, which may fail to containall the information that can be extracted by training an ML model onrepresentative data. I present a method based on redshift dispersionto improve photometric redshift predictions compared to both machinelearning and template fitting.
2021-02-15 Will Hartley ** Understanding the galaxy population of the Universe (work in progress)
Expanding our knowledge of the population of galaxies that inhabit the Universe is usually considered an aspect of observational cosmology pursued by galaxy evolution enthusiasts. But the use of galaxies, and their observed ellipticities, as probes of the matter content of the Universe via the effect of weak gravitational lensing (WL), has brought the fields of galaxy evolution and cosmological parameter estimation into a sort of awkward confluence. The requirements of WL experiments, such as Euclid, and the rise of likelihood-free inference methods have triggered a flurry of activity in developing an accurate knowledge of the statistical galaxy population observable by these experiments. I will show some early-stage work I am conducting in this area to measure the galaxy luminosity function and produce catalogue-level simulations of objects that will be observed by Euclid.
2021-02-22 Skipped
2021-03-01 Hancheng Li ** Polarization measurements of the Crab Pulsar with POLAR (work in progress)
POLAR is a dedicated Gamma-Ray Burst (GRB) polarimeter making use of Compton-scattering which took data from the second Chinese spacelab, the Tiangong-2 from September 2016 to April 2017. It has a wide Field of View (FoV) of about 6 steradians and an effective area of approximately 400 cm2 at 300 keV. These features make it one of the most sensitive instruments in its energy range (15-500 keV), and therefore capable almost continuously monitoring persistent sources such as pulsars. Significant folded pulsation from both PSR B0531+21 (the Crab Pulsar) and PSR B1509-58 has been observed. Observations of the Crab Pulsar with POLAR have previously been used for: 1). pulsar navigation test to predict orbit information of Tiangong-2; 2). phase-resolved spectroscopy of the Crab Pulsar to calibrate the instrumental responses of POLAR. In this work, we investigate a polarimetric joint-fitting method for observations of the Crab Pulsar with POLAR. Unlike a GRB observation with POLAR, the observations of the Crab Pulsar are complicated by multiple observational datasets during which the polarization plane rotates as well. So before fitting, we have to correct the modulation curves under different datasets, with taking into account the rotations of the Crab Pulsar’s relative position in the detctor’s local coordinate, and the changes of detector response in different datasets. Despite these difficulties and the low signal to background for such sources constraining polarization measurements were possible with the POLAR data. We will present the developed methodology, which could be applied to any wide FoV polarimeter, and the preliminary polarization results of the Crab pulsar with POLAR.
2021-03-08 Devina Misra ** The origin of pulsating ultra-luminous X-ray sources
Ultra-luminous X-ray sources (ULXs) are those X-ray sources located away from the centre of their host galaxy with luminosities exceeding the Eddington limit of a stellar-mass black hole (Lx>10^39 erg/s). Observed X-ray variability suggests that ULXs are X-ray binary systems. The discovery of X-ray pulsations in some of these objects (e.g. M82~X-2) suggests that a certain fraction of the ULX population may have a neutron star as the accretor. These binaries are transferring mass at super-Eddington rates, however, the lower Eddington limit of neutron stars makes pulsating ULXs very difficult to explain by classical accretion physics. There are many ideas proposed to explain these sources, ranging from geometrical beamed emission to strong magnetic fields and irradiation-driven winds. Firstly, we explored the allowed initial parameter space of binary systems consisting of a neutron star and a donor star that could explain the observed properties of ULXs, using MESA. We show that observed super-Eddington luminosities can be achieved in X-ray binaries undergoing non-conservative mass transfer while assuming geometrical beaming. In order to contain the physics of accretion, we study populations of X-ray binaries under different assumptions of the accretion physics. Using POSYDON, a framework that combines the computational benefits of rapid binary populations synthesis codes and the detailed calculations of stellar/binary evolution codes, we generate multiple synthetic populations of X-ray binaries and study their evolution. In this talk I will explain our methodology and the work done so far in this regard.
2021-03-15 Skipped
2021-03-22 Vitali Sliusar ** Mrk421 and Mrk501 as high-energy astrophysics laboratories to study geometrical and temporal properties of blazars emission
The high-synchrotron-peaked blazars Mrk 421 and Mrk 501 are close bright and well-studied active galactic nuclei, which feature persistent GeV and TeV emission. Both sources show relentless variability across the electromagnetic spectrum on different time scales from minutes to years. I will discuss the variability and derive constraints on the emission mechanism model parameters using long-term multi-wavelength light curves from radio to TeV. During the considered period from 2012 to 2018, both blazars found in various activity states, particularly Markarian 501 reached a quiescent state after August 2016. I will show results of the light curves correlation analysis, identification of individual flares, and search for inter-band connections, which are expected assuming shock propagations within the jet. The fractional variability for both blazars shows a two-bump structure with the highest variability in the X-ray and TeV bands. The lag between X-ray and TeV light curves in Mrk 421 was found to be close to zero, supporting the SSC emission scenario. The variability of Mrk 501 on the long-term scale is also consistent with SSC except for the periods of high activity when the introduction of a second small emission region enhances the SED fitting.
2021-03-29 Simone Bavera ** Probing the progenitors of spinning binary black-hole mergers with long gamma-ray burst observations
Long duration gamma-ray ray bursts (LGRBs) are thought to be associated with the collapse of massive, rapidly spinning stars and the formation of compact objects. Developments in asteroseismology point towards efficient angular momentum transport inside stars, which implies that the core of massive stars slows down after they expand to become super-giants and lose any significant initial angular momentum via stellar winds or binary mass transfer. On the other hand, tidal interactions in close binary systems can maintain a star tidally locked to short orbital periods leading to the formation of spinning black holes. I will discuss how the formation of fast spinning binary black hole (BBH) mergers, originating from the evolution of isolated binaries and involving a common envelope phase or chemically homogeneous evolution, are associated with LGRBs. Using population synthesis studies that employ detailed stellar structure and binary evolution calculations, we find that these BBH formation pathways, which well reproduce all the GW observable properties of the so far detected BBH sample, can also account for up-to the majority of the observed luminous LGRBs. Because of the short merger timescale of these highly spinning BBHs, LGRBs can probe their formation throughout cosmic time, outside current gravitational waves detectors' horizons.
2021-04-05 Holidays
2021-04-12 Nami Mowlavi ** Large-amplitude variables from the Gaia mission
The Gaia mission has published in its data release 2 (DR2) variability information and light curves for only half a million variable stars among the ~1.7 billion sources available in the release. I will show in this presentation how information on large-amplitude variables can still be extracted from the full sample of stars available in the public archive, and how the unique characteristics of the Gaia mission enable to study multi-band variability properties of various types of variable stars.
2021-04-19 Guillaume Desprez ** Exploring the limits of information contained in the Euclid photometry
Information about the physical parameters of a galaxy is encrypted in its Spectral Energy Distribution (SED). Large photometric surveys allow us to observe millions of galaxies. However, due to the use of broad band filters, the information contained in the SEDs is limited. The strategy of a survey, like the selection of bands or the depth of the survey, impact the limit of information accessible about galaxy parameters. I explore the limits of the Euclid survey photometry, using simulated Euclid photometry data and a simple machine-learning algorithm to estimate in different scenarii (from infinity precise photometry to observed photometry) the contraints that the Euclid survey strategy imposes on the galaxy physical parameters estimation.
2021-04-26 Konstantinos Kovlakas ** A new galaxy catalogue and applications on interesting binaries
We describe a new galaxy catalogue, the HECATE, initially constructed to aid a study of ultraluminous X-ray sources (ULXs) in the local Universe, which can be a useful tool for transient, multi-wavelength and multi-messenger astronomy. We present the census of ULX populations based on the Chandra Source Catalog 2.0 and the HECATE, and estimate the correlation with the star-formation rate, stellar mass, and metallicity of the host galaxies. We confirm previous results, and discover an excess in low-stellar-mass early-type galaxies, which we reproduce using binary population synthesis models, and realistic star-formation histories. In addition, we apply the HECATE for the localization of the host galaxies of gravitation-wave sources, which is crucial for detecting potential electromagnetic counterparts. Finally, we briefly discuss other applications of the HECATE.
2021-05-03 Marco Tucci ** Performance of object classification in the Euclid Data Challenge 2 catalog
Classification will be an important task for upcoming surveys such as Euclid that will detect billions of new sources. Conventional techniques for star/galaxy classification based on selections in magnitude and morphology are not accurate enough for deep surveys. Machine learning (ML) algorithms appear instead to be very well suited to classification tasks using morphological and photometric information.We applied a Random Forest method to classify objects within the Data Challenge 2 catalog. This catalog was built from real images in the COSMOS field with the aim to match the expected properties of Euclid data, in terms of photometric bands and depth. The performance of classification of objects as galaxies, stars and QSOs is presented for models that take into account photometry with or without morphological information. We then analyze the impact of adding extra features such as template fitting results. The presentation ends with a discussion on the choice of training sets for classification and on future developments.
2021-05-10 Laurent Eyer ** The variability of white dwarfs through Gaia’s eyes.
Gaia has revealed an unprecedented view of the white dwarf sequence by pinpointing 260,000 of these in the colour-absolute magnitude diagram.In this presentation, we explore the variability of the white dwarf sequence thanks to averaged values of the photometry from the Gaia public archive (DR2 and EDR3). We identify some over-densities and check some results with ZTF photometry.
2021-05-17 Nicolas Produit ** Where are we with POLAR-2
POLAR-2 is the successor to the very successful POLAR mission.I will explain how POLAR-2 will achieve a gain of a factor 10 in sensitivity versus POLAR. I will speak about the actual work to insurethat the new technologies we want to use will indeed work in space.
2021-05-24 Holidays
2021-05-31 Andrea Tramacere ** Adiabatic expansion and self-consistent modeling of Radio-gamma delay in Blazars with the JetSeT code
Light curves in long-term campaigns have shown that, for several blazars, the gamma-ray emission occurs with a significant delay w.r.t. to high-energy bands,with time scales ranging from week to years. Such observational evidence has been a matter of debate for several years, and usually is understood in terms ofdifferent distances of the gamma-ray and radio transparent region.I will show, by means of a self-consistent numerical modeling, that the adiabatic expansion of the relativistic blobs can explain these delays, reproducing lags compatible with the observed time scales.I will use the JetSeT framework to reproduce the numerical modeling of the radiative and accelerative processes, reproducing the temporal evolution of a single blob, from the initial flaring activity, and the subsequent expansion.I will present the spectral evolution and the corresponding light curves, investigating the relations among the observed parameters, rise time, delay, and decay time, and identification of the link with the physical parameters.Simulations show that when adiabatic expansion is active, lags due to the shift of the synchrotron frequency. The corresponding time lags has an offset equal to the distance in time between the flaring onset and the beginning ofthe expansion, whilst the rising and decaying time scales depends on the velocity of the expansion and on time required to the source to exhibit a synchrotron self-absorption frequency below the relevant radio spectral window.An inter-band response function is derived, embedding the aforementioned parameters, and is compared with the Radio-gamma empirical response obtained from observational data.
2021-06-07 Lingsong Ge ** Bayesian analysis of AGN X-ray spectral properties and evolution in XMM-COSMOS survey
To understand the cosmological evolution of supermassive black holes (SMBHs) and its relation with that of galaxies, it is necessary to study the demographic properties of active galactic nuclei (AGNs) over cosmic time, which is a representation of the accretion history of SMBHs. However, it is challenging to make an unbiased study of the AGN population, because first AGNs are surrounded by gas and dust which strongly affect their direct observation, and second there are various components in the X-ray spectrum of AGN that are difficult to constrain with moderate to low S/N data from large surveys. We developed a new Bayesian framework of AGN X-ray spectral analysis to automatically fit the spectra and reconstruct the parent population of main parameters, e.g. the photon index (Gamma) and hydrogen column density (nH) without much bias. In this talk I will recap the method including spectral fitting and population inference, which I talked about separately before, and mainly present our final results on the XMM-COSMOS sample of 819 sources detected in 2-7 keV band, 663 (81%) of which have spectroscopic redshift.
2021-06-14 Dominique Eckert ** Feedback from active galactic nuclei in galaxy groups
The co-evolution between supermassive black holes and their environment is most directly traced by the hot atmospheres of dark matter halos. The cooling of the hot atmosphere supplies the central regions with fresh gas, igniting active galactic nuclei (AGN) with long duty cycles. On the other hand, outflows from the central engine tightly couple with the surrounding gaseous medium. The outflowing material provides the dominant heating source preventing runaway cooling by carving cavities and driving shocks across the medium. I recently wrote an invited review paper on the topic, in which we reviewed our knowledge of the AGN feedback process in the specific context of galaxy groups, i.e. dark matter halos in the mass range 1e13-1e14 Msun. In these systems, the energy that is supplied by the central AGN to the hot intragroup medium can exceed the gravitational binding energy of halo gas particles, such that the hot gas content of galaxy groups is highly sensitive to the injection of energy by AGN feedback. I will review the state-of-the-art in observations of the feedback phenomenon and in theoretical models of the heating-cooling balance in galaxy groups. I will also describe how our knowledge of the AGN feedback process impacts galaxy evolution models and large-scale baryon distributions. Finally, I will discuss how new instrumentation will answer key open questions on the topic.
2021-06-21 Berry Holl ** --
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