BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:On the coronal temperature and its variability DTSTART;VALUE=DATE-TIME:20230626T143000Z DTEND;VALUE=DATE-TIME:20230626T144500Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-895@cern.ch DESCRIPTION:Speakers: Jia-Lai Kang (University of Science and Technology o f China)\nThe hard X-ray emission universally found in AGN is believed to be produced in the so-called corona\, of which the physical nature remains unclear. A fundamental parameter is the coronal temperature ($T_{\\rm c}$ )\, which could be measured by fitting the high-energy cutoff ($E_{\\rm cu t}$) in the hard X-ray spectra. With multiple NuSTAR observations\, we sea rch for the variation of $T_{\\rm c}$/$E_{\\rm cut}$ in individual sources . We get a small sample of several sources\, which demonstrate an interest ing non-monotonic variation pattern\, with a break point of the photon ind ex $\\Gamma$ detected. Sources are found to be “hotter-softer-when-brigh ter” at $\\Gamma < 2.05$\, but turn into “cooler-softer-when-brighter ” at $\\Gamma > 2.05$. Such a behavior indicates that multiple mechanism s\, for instance\, changes of the coronal geometry and the cooling efficie ncy\, are contributing to the X-ray variability in AGN. Meanwhile\, we are also interested in how $T_{\\rm c}$/$E_{\\rm cut}$ differs from one sourc e to another. We measure the $T_{\\rm c}$/$E_{\\rm cut}$ in a large sample and investigate the correlations between $T_{\\rm c}$ and other parameter s (photon index $\\Gamma$ and Eddington ratio). A strong positive correlat ion between $T_{\\rm c}$ and Γ is detected\, while none between $T_{\\rm c}$ and Eddington ratio. In other words\, counter-intuitively\, hotter cor onae tend to produce softer spectra\, while the accretion rate is not a pr imary determinant of the coronal temperature.\n\nhttps://indico.unina.it/e vent/61/contributions/895/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/895/ END:VEVENT BEGIN:VEVENT SUMMARY:Identifying low accretion rate AGN and studying their X-ray variab ility with the EPIC XMM Outburst Detector Ultimate System (EXODUS) DTSTART;VALUE=DATE-TIME:20230626T160000Z DTEND;VALUE=DATE-TIME:20230626T161500Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-924@cern.ch DESCRIPTION:Speakers: Maitrayee Gupta (Institute for Research in Astrophys ics and Planetology (IRAP)\, CNRS\, Toulouse\, France)\nTemporal variabili ty of flux across the electromagnetic spectrum is a commonly observed phen omenon in Active Galactic Nuclei (AGN)\, however the phenomenon is not wel l studied in low accretion rate AGN\, primarily due to difficulties identi fying them in X-ray catalogues due to their lower luminosity.\nIn this wor k\, we use our algorithm EXODUS\, which searches for variability in the wh ole of *XMM-Newton*'s EPIC field of view and is agnostic of source detecti on and the number of counts. It accomplishes this by binning the observati ons into short time windows and comparing the pixel counts per window to t he median pixel counts to detect variable sources within the observation\, making EXODUS ideal for studying faint rapid X-ray transients. We apply E XODUS to all of the observations that comprise the 4XMM-DR11 catalogue to create a reliable subset of low Eddington ratio AGN. Understanding these A GN helps us to develop a more complete framework constraining the presence /absence of the corona from the hardness/softness of spectra during the lo w accretion phase. Additionally\, we measure black hole masses\, variabili ty timescales\, and the prominence of their coronal/disc emission by study ing the effect of the different modes of AGN accretion on line-emitting ga s. We compare the results of this study with those of our previous X-ray s tudies on moderate accretion rate AGN selected from the BAT AGN Spectrosco pic Survey sample.\n\nhttps://indico.unina.it/event/61/contributions/924/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/924/ END:VEVENT BEGIN:VEVENT SUMMARY:X-ray polarimetry of Seyferts and the nature of the hot corona DTSTART;VALUE=DATE-TIME:20230626T163000Z DTEND;VALUE=DATE-TIME:20230626T164500Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-868@cern.ch DESCRIPTION:Speakers: Francesco Ursini ()\nWe present the first X-ray pola rimetric measurements of three Seyfert 1 galaxies with IXPE\, the NASA/ASI mission operating as of December 2021. The results allow us to directly c onstrain the geometrical shape of the hot corona for the first time. We di scuss the implications for the physical interpretation of X-ray variabilit y in these sources.\n\nhttps://indico.unina.it/event/61/contributions/868/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/868/ END:VEVENT BEGIN:VEVENT SUMMARY:X-ray variability of SDSS quasars DTSTART;VALUE=DATE-TIME:20230626T161500Z DTEND;VALUE=DATE-TIME:20230626T163000Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-870@cern.ch DESCRIPTION:Speakers: Guido Risaliti (Università di Firenze)\nI present t he analysis of a sample of several hundred SDSS quasars with multiple sere ndipitous XMM-Newton observations. The X-ray to UV luminosity relation all ows to predict the average X-ray flux\, and to select only the X-ray obser vations that are deep enough to remove any bias towards higer-than-average flux states. The optical/UV SDSS spectrum allows to investigate the relat ion between X-ray variability and the total luminosity\, the black hole ma ss\, and the Eddington ratio. Considering that the optical/UV and X-ray ob servations are not correlated\, I conclude that most of the "intrinsic" di spersion of the X-ray to UV relation is due to X-ray variability.\n\nhttps ://indico.unina.it/event/61/contributions/870/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/870/ END:VEVENT BEGIN:VEVENT SUMMARY:X-ray variability properties of the BASS unobscured AGN from XMM-N ewton observations. DTSTART;VALUE=DATE-TIME:20230626T154500Z DTEND;VALUE=DATE-TIME:20230626T160000Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-866@cern.ch DESCRIPTION:Speakers: Alessia Tortosa (Instituto de Estudios Astrofísicos \, Facultad de Ingeniería y Ciencias\, Universidad Diego Portales)\nI wil l present the analysis of the X-ray variability properties of the Seyfert 1 Galaxies belonging to the BAT AGN Spectroscopic Survey (BASS) using XMM- Newton observations. This sample includes more than 500 observations of 15 1 local AGN (medium redshift z=0.06). The aim of this work is to constrain the relation between the common estimators of the variability amplitude ( i.e.\, fractional variability and normalised excess variance)\, calculated in different energy bands\, with the physical and accretion properties of AGN such as the black hole masses of the central supermassive black hole (known for all the sources of the BASS sample from either broad Balmer lin es or reverberation mapping estimations) and Eddington ratios (estimated c ombining the black hole masses measurements with the estimates of the bolo metric luminosity derived from the BAT 14-150 keV luminosity). As expected from previous studies we find a strong anti-correlation between the exces s variance and the black hole mass. We do not find correlation between the excess variance and the Eddington ratio but we find a strong anti-correla tion with the 2-10 keV luminosity\, which disappears when we removed the d ependence of the excess variance on the black hole mass. Exploring the rel ation of excess variance in different energy bands we found that the varia bility of the sources of our sample is mostly due to the flux variation of the primary continuum and/or of the reflection component\, at least on sc ale of 10ks. I will also show the comparison of the variability property o f the unobscured AGN of the BASS sample with the X-ray variability propert ies of a sample of 5 Super and Hyper-Eddington sources (1$\n\nhttps://indi co.unina.it/event/61/contributions/866/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/866/ END:VEVENT BEGIN:VEVENT SUMMARY:Exploring black hole scaling relations via the ensemble variabilit y of active galactic nuclei DTSTART;VALUE=DATE-TIME:20230626T153000Z DTEND;VALUE=DATE-TIME:20230626T154500Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-864@cern.ch DESCRIPTION:Speakers: Antonis Georgakakis (NOA)\nOne of the most influenti al relations in extragalactic astrophysics is the one that links the stell ar-mass component of galaxies (Mstar) to the masses of the supermassive bl ack holes (MBH) at their centres. Observational constraints on the shape\, normalisation and redshift evolution of the Mstar-MBH relation provide im portant clues on the co-evolution of galaxies and their supermassive black -holes. Unfortunately\, measuring the Mstar-MBH relation\, particularly at higher redshifts\, is challenging and prone to systemics. In this contrib ution I will present a new method that provides a handle on the Mstar-MBH relation by modelling the ensemble variability of X-ray selected AGN sampl es. A key ingredient of the method is the modelling strategy that links\, for the first time\, the demographics of AGN to the physics of the stochas tic flux variations of accretion flows and allows the interpretation of th e variability properties of AGN populations. I will demonstrate the predic tive power of the model by comparing in a forward manner with observationa l measurements of the ensemble excess variance of X-ray AGN in the Chandra Deep Field South. I will also discuss future prospects for joint constrai nts on both models of AGN variability and the Mstar-MBH relation as a func tion of redshift.\n\nhttps://indico.unina.it/event/61/contributions/864/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/864/ END:VEVENT BEGIN:VEVENT SUMMARY:The universal shape of the X-ray variability power spectrum of AGN up to z ∼ 3 DTSTART;VALUE=DATE-TIME:20230626T151500Z DTEND;VALUE=DATE-TIME:20230626T153000Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-867@cern.ch DESCRIPTION:Speakers: Maurizio Paolillo (Università di Napoli Federico II )\nWe present a study of the ensemble X-ray variability of Active Galactic Nuclei (AGN) over a large range of timescales (20 ks ≤ T ≤ 14 yrs)\, redshift (0 ≤ z ≲ 3)\, luminosities ($10^{40} \\leq L_X \\leq 10^{46}\ \ \\mbox{erg s}^{−1}$) and black hole (BH) masses $10^6≤M_⊙≤10^9$) . Through the use of the "variance–frequency diagram"\, as a viable alte rnative to the power spectral density (PSD)\, we show that the data collec ted from archival observations and previous literature studies are consist ent with a universal PSD form which does not show evidence for systematic evolution of shape or amplitude with redshift or luminosity. We find new e vidence that the PSD bend\nfrequency depends on BH mass and\, possibly\, o n accretion rate. We will discuss the implications for current and future AGN population and cosmological studies\n\nhttps://indico.unina.it/event/6 1/contributions/867/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/867/ END:VEVENT BEGIN:VEVENT SUMMARY:Opportunities and challenges for spectral-timing models of AGN DTSTART;VALUE=DATE-TIME:20230626T141500Z DTEND;VALUE=DATE-TIME:20230626T143000Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-874@cern.ch DESCRIPTION:Speakers: Andrew Young (University of Bristol)\nX-ray reverber ation mapping studies of AGN can\, in principle\, be used to measure the b lack hole mass and spin\, the accretion disc and corona geometries\, and t he ionisation state of the disc. We report on our efforts to fit the spect ra and time lags of a number of AGN\, but focus primarily on two sources\, 1H 0707-495 and IRAS 13224-3809. We can explain the low- and high-frequen cy lags\, find that an extended corona is required\, estimate the black ho le masses\, and find there are different correlations between parameters i n each object as their coronae change. However\, this model is slow to eva luate\, the parameter space had to be limited (e.g.\, fixed spin\; simplif ied geometry)\, it was difficult to characterise the error bars and degene racies in the model\, and the data were fairly noisy. We will discuss how new approaches to modelling and improved data will lead to a better unders tanding of the inner workings of AGN.\n\nhttps://indico.unina.it/event/61/ contributions/874/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/874/ END:VEVENT BEGIN:VEVENT SUMMARY:Review: X-ray variability of AGN DTSTART;VALUE=DATE-TIME:20230626T134500Z DTEND;VALUE=DATE-TIME:20230626T141500Z DTSTAMP;VALUE=DATE-TIME:20260310T132645Z UID:indico-contribution-185-903@cern.ch DESCRIPTION:Speakers: Guglielmo Mastroserio ()\nSupermassive black holes p reserve information on the growth of the host galaxy and its dynamic evolu tion. Thus\, constraining their parameters is crucial to shed light on the ir formation and evolution. In recent years\, X-ray astronomy has undergon e a renaissance\, with several instruments that perform large observationa l campaigns and cover an extremely wide range of energy timescales to stud y Active Galactic Nuclei (AGN). The X-ray radiation produced by the closes t accreting matter to the black hole shows distortions due to the strong r elativistic effects. Proper modeling of these features constrains the syst em geometry and the interplay between the corona and the accretion disk. I will review the recent results of X-ray spectral timing analyses with an emphasis on the interpretation of the observations.\n\nhttps://indico.unin a.it/event/61/contributions/903/ LOCATION:Centro Congressi Federico II Aula Magna URL:https://indico.unina.it/event/61/contributions/903/ END:VEVENT END:VCALENDAR