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William Brandt (Penn State University)07/10/2024, 09:00Invited
I will briefly review what X-ray surveys and their multiwavelength follow-up have revealed about the sources constituting the cosmic X-ray background (CXRB), focusing on results from the past 25 years from missions including Chandra, Einstein Probe, INTEGRAL, NuSTAR, SRG, Swift, and XMM-Newton. I will first detail the identification, classification, and basic nature of the extragalactic...
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Mark Lacy (National Radio Astronomy Observatory)07/10/2024, 09:40Invited
Surveys of the radio sky have a long history, dating back to the very early days of radio astronomy. These early surveys provided crucial input to our understanding of both cosmology and the AGN/quasar population. As the field of radio astronomy has evolved so to have survey techniques, resulting in the current "Golden Age" of radio surveys. Wide-field surveys today cover frequency ranges from...
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Prof. Marat Gilfanov07/10/2024, 10:10Invited
After more than two years of scanning the sky the eROSITA X-ray telescope aboard SRG orbital observatory produced the best ever X-ray maps of the sky and discovered more than three million X-ray sources, of which about 20% are stars with active coronas in the Milky Way, and most of the rest are galaxies with active nuclei, quasars and clusters of galaxies. eROSITA detected over 10^3 sources...
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Peter Predehl (Max-Planck-Institut für extraterrestrische Physik)07/10/2024, 11:10Invited
5 years after the launch from the Russian Baikonur Cosmodrome, all systems and instruments of the Spektr-RG (SRG) observatory are working perfectly. With eROSITA, the German contribution to this mission, half of all 8 sky surveys have been completed so far. Millions of X-ray sources, mostly of an extragalactic nature, have been discovered. This has confirmed what we had hoped for before the...
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Alexander Lutovinov07/10/2024, 11:40Invited
An overview of highlights and discoveries from Mikhail Pavlinsky ART-XC telescope on board the SRG observatory is presented. Since 2019 SRG/ART-XC has conducted several full all sky surveys as well as a deep survey of our Galaxy. As a result, we obtained the catalogue of hard X-ray sources detected at the all sky, which includes more than one and a half thousand objects, most of them are...
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68. Machine learning models for SRG/eRosita extragalactic sky: challenges, results and perspectives.Alexander Meshcheryakov07/10/2024, 12:10Invited
During the 2.5 years in 2019-2022 the eROSITA telescope onboard the SRG space observatory produced a deep all-sky survey in soft X-rays. The competitive analysis of this unique data requires: firstly, massive usage of publicly available sky surveys (photometric, spectroscopic, astrometric) in the broad spectral range from Radio to UV; secondly - intensive application of modern machine learning...
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Rashid Sunyaev07/10/2024, 14:30Invited
SRG/eROSITA and microwave observations of clusters of galaxies
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Chen Zhang (National Astronomical Observatories, Chinese Academy of Sciences)07/10/2024, 15:10Invited
The Einstein Probe mission is a dedicated satellite for time-domain astrophysics collaborated with ESA, MPE as well as CNES, which was launched on Jan. 9, 2024. There are two payloads onboard EP, the Wide-Field X-ray telescope (WXT) and the Follow-up X-ray telescope (FXT). WXT employ the Lobster-Eye Optics with FOV of about 3830 square degrees by 12 modules. FXT employ traditional Wolter-I...
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Prof. Xu Kong (University of Science and Technology of China)07/10/2024, 15:40Invited
Wide Field Survey Telescope (WFST) is the largest time-domain survey facility in the northern hemisphere. The telescope is a dedicated photometric surveying facility being built jointly by the University of Science and Technology of China (USTC) and the Purple Mountain Observatory(PMO). It is equipped with a 2.5-meter diameter primary mirror, an active optics system, and a mosaic CCD camera...
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Lian Tao (Institute of High Energy Physics, Chinese Academy of Sciences)07/10/2024, 16:10Invited
As China's first X-ray astronomy satellite, Insight-HXMT has been successfully operating in orbit for over seven years since its launch in 2017, producing substantial findings in the study of compact objects. As a next-generation space mission, CATCH will utilize the collaborative capabilities of a multi-satellite constellation, presenting significant scientific potential in exploring the...
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Roman Krivonos (Space Research Institute (IKI), Moscow, Russia)07/10/2024, 17:10Solicited
The INTEGRAL hard X-ray surveys have proven to be of fundamental importance. In more than twenty years of operation, the INTEGRAL observatory has given us a sharper view of the hard X-ray sky, and provided the triggers for many follow-up campaigns from radio frequencies to gamma-rays. In addition to conducting a census of hard X-ray sources across the entire sky, INTEGRAL has carried out...
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Karl-Heinz Kampert (Universität Wuppertal)07/10/2024, 17:35Invited
The Pierre Auger Observatory is conceived to study ultra-high energy cosmic rays from about 10^17 eV to beyond 10^20 eV. It is a multi-hybrid Observatory comprising 1660 surface detector stations spread over an area of 3000 km2 over-looked by 27 imaging Fluorescence telescopes erected at four sites at its periphery. Each of the detector stations consists of a 10 m2 water Cherenkov detector...
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Anna Uryson (Lebedev Physical Institute of Russian academy of science)07/10/2024, 18:05Regular
We discuss propagation of heavy nuclei at energies higher than 10 19 eV from their sources to the Earth, assuming them to be of extragalactic origin. In extragalactic space nuclei interact with background emission and inevitably decay. Analyzing the content of heavy nuclei arriving the Earth we reveal their energy at the Earth as a function of the source-Earth distance. It is found that the...
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Paolo Padovani08/10/2024, 09:00Invited
After the 2017 association between the blazar TXS 0506+056 and high-energy IceCube neutrinos, there has been a surge of research exploring the potential link between blazars and neutrinos. In 2022, somewhat surprising evidence emerged for neutrino emission from the nearby prototype Seyfert II galaxy, NGC 1068. This raises the question: which, if any, AGN are neutrino emitters, and why? What...
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Narek Sahakyan (ICRANET-Armenia IO)08/10/2024, 09:30Invited
The integration of Artificial Intelligence (AI) into astronomy and astrophysics marks a transformative era in the exploration of the Universe, enhancing the analysis of vast data sets with unparalleled efficiency and precision. AI is revolutionizing the usability of observational data, expanding our understanding of various cosmic phenomena. Blazar research particularly benefits from the...
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Meredith Powell (Leibniz Institute for Astrophysics Potsdam (AIP))08/10/2024, 10:00Regular
The cosmic environments of accreting supermassive black holes provide powerful insights on the intertwined histories of structure growth, black hole growth, and galaxy evolution. One way to probe these environments is via the spatial clustering of active galactic nuclei (AGN). Using new data from the BASS and HETDEX wide-field surveys, I will present recent AGN clustering measurements as a...
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Prof. Remo Ruffini (ICRANet)08/10/2024, 10:20Invited
We were quite fortunate with John Wheeler introducing the concept of Black Hole (BH) and more important using the Kerrr mathematical solution to find the BH mass energy formula with Christodoulou and Hawking. We have been equally fortunate to participate in developing the largest observational effort extending to the earliest million years from the Big Bang and observing BH in all range of...
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Mikhail Belvedersky (IKI RAS, HSE University)08/10/2024, 11:20Regular
We search for reflection-dominated Compton-thick active galactic nuclei (CT AGN) candidates in the Lockman Hole region using the SRG/eROSITA Lockman Hole survey data. To this end, we selected sources with anomalously hard photon indexes in the 0.3 $-$ 8.0 keV band, untypical for type I AGN. In particular, we required that the upper end of the 90% error interval did not exceed a fudicial...
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Marko Micic08/10/2024, 11:35Regular
Recent discoveries of supermassive black holes existing less than 500 million years after the Big Bang represent a major puzzle. How did these black holes grow so much in such a short time? In this talk, I will discuss how the early Universe environmental conditions could have led to an accelerated black hole growth. The prevailing wisdom suggests that the early Universe is dominated by dwarf...
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Elena Fedorova (1) INAF-OAR 2) AO KNU)08/10/2024, 11:50Regular
We present a comprehensive multi-wavelength analysis of NGC 1275/Perseus A, focusing on its X-ray and gamma-ray emission over a 24-year period (2000-2024). Our study utilizes data from multiple space-based observatories, including SUZAKU, XMM-Newton, SWIFT, and INTEGRAL. The X-ray data observed by Suzaku/XIS were treated using a model-independent method for separating the spectral components...
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Gregory Vereshchagin08/10/2024, 12:05Invited
We will discuss pair creation by electrically neutral compact astrophysical objects, having sufficiently sharp positively charged surface boundary to create an electrosphere with overcritical electric field. Two types of energy sources will be considered: heat and radial electromagnetic perturbation. Implications for astrophysical observations will be outlined.
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Dr Razmik Mirzoyan (Max-Planck Institute for Physics)08/10/2024, 14:15Invited
In this report we would like to discuss recent developments in ground-based gamma-ray astrophysics. Since the 1990s, very high energy gamma rays have been studied with the Imaging Atmospheric Cherenkov Telescopes (IACT), which measure the Cherenkov light component of air showers. These have high sensitivity in a field of view of several degrees and can provide angular resolution on the order...
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Dr Elena Pian (INAF-OAS, Bologna)08/10/2024, 14:45Invited
The Cherenkov Telescope Array will bring an entirely new view on high-energy transients. This opportunity will be enhanced by the coming on line of various large field-of-view ground-based and orbiting facilities that will paint a multi-wavelength picture of the variable sky. I will discuss some of the exploration areas and projects development, including the VST Polarimetric camera (VSTPol).
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Antonio Stamerra (INAF-OAR)08/10/2024, 15:15Regular
Extragalactic TeV astronomy with Cherenkov telescopes is synergistic with multi-frequency and multi-messenger observations, conducted through observational campaigns or triggers (target of opportunities).
We will outline these two main directions by presenting recent results from multifrequency observations of blazars, such as the quasi-periodic PG1553+113, and by discussing the prospects...
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Dr Martin LEMOINE (APC (CNRS - U. Paris Cite))08/10/2024, 15:35Invited
The acceleration of charged particles to very high energies in powerful astrophysical sources such as pulsar winds, active galactic nuclei, gamma-ray bursts etc., represents a central question in modern high-energy astrophysics, astroparticle physics and nowadays, multi-messenger astronomy. Accelerated particles can interact with and radiate in ambient fields to produce secondary photon or...
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Abhradeep Roy08/10/2024, 16:35Regular
The blazar 1ES 1218+304 is a high-frequency peaked BL Lac object at a cosmological redshift z of 0.182. It was first detected in Very-High Energies (VHE, E>100 GeV) by the MAGIC telescope in 2006. 1ES 1218+304 is known for showing strong flux variability with occasional outbursts across the electromagnetic spectrum. This source also exhibits an atypically hard VHE spectrum. The Large-Sized...
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Alexander Mikhailov08/10/2024, 16:55Regular
The modern radio sky surveys have shown that compact radio sources, so named FR0 radio galaxies, are the majority among radio loud active galactic nuclei of the local Universe. The numerous FR0 population have to make a significant contribution to cosmic background emissions. These sources have mildly relativistic jets at parsec scales despite lack of prominent extended kpc radio structures....
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Luis Ho (Kavli Institute for Astronomy and Astrophysics, Peking University)08/10/2024, 17:10
Supermassive black holes are ubiquitous in the nearby Universe. AGN feedback is thought to be a key mechanism that regulates the growth of supermassive black holes and their joint evolution with their host galaxies. How and when did these mysterious objects form? How did they grow quickly enough to power high-redshift quasars? I will summarize recent discoveries made with the JWST that offer...
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Jinyi Yang08/10/2024, 17:50
The formation and growth of the earliest supermassive black holes (SMBHs) and the assembly of early massive galaxies are among the most important open questions. As the most luminous non-transit objects, quasars at z > 6 are indispensable probes of the early Universe. The recent high-z quasar surveys have pushed quasar frontier to z>7.5. The launch of JWST opens up a new era in the study of...
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Prof. Massimo Della Valle (INAF-Capodimnonte, Naples)09/10/2024, 09:00Invited
Supernovae are among the most energetic and luminous events in the universe, providing unique opportunities to study stellar evolution, nucleosynthesis, the dynamics of interstellar matter, and the physics of stellar remnants such as neutron stars and black holes. The next galactic supernova could offer unprecedented insights if we are adequately prepared to discover it. This paper briefly...
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Paolo Mazzali09/10/2024, 09:30Invited
The properties of the broad-lined Type Ic Supernovae that are typically
discovered in coincidence with long-duration Gamma-ray Bursts will be reviewed,
and compared to those of other Supernovae for which GRBs are not observed.The SNe associated with GRBs are of Type Ic. They are brighter than the norm,
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and show very broad absorption lines in their spectra, indicative of high
expansion... -
Dr Charlotte Ward (Princeton University)09/10/2024, 10:00Invited
Wide-field time-domain surveys across the multi-wavelength spectrum have revealed a complex array of transient and variable phenomena from SMBH populations, including flares from tidal disruption events (TDEs), ‘changing-look’ events when AGN broad lines appear or disappear following an optical flare, and other classes of extreme AGN variability. These events provide important insights into...
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Dheeraj Pasham (MIT)09/10/2024, 10:30Invited
Almost all galaxies contain a supermassive black hole (masses > 100,000 solar masses) residing at their center. In the last decade or so a subsample of these black holes are found to exhibit repeating X-ray modulations with timescales ranging from a few minutes to up to a month. The nature of these recurring signals is currently debated but most ideas can be put into two categories: they are...
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Taeho Ryu (Max Planck Institute for Astrophysics)09/10/2024, 11:30Invited
Galactic nuclei are extreme environments where stars are densely packed around a supermassive black hole (SMBH). Occasionally, dynamical interactions in the galactic center cause stars to interact violently at short distances with each other or with the SMBH, resulting in the formation of nuclear transients. In this talk, I will discuss two types of extreme nuclear transients: extreme tidal...
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Jonathan Quirola (Radboud university)09/10/2024, 12:00Solicited
Extragalactic Fast X-ray Transients (FXTs) are X-ray flashes lasting minutes to hours. Their nature is unclear, but the most remarkable scenarios related to them are shock breakout supernovae, tidal disruption events involving white dwarf stars and intermediate massive black holes, and binary neutron star mergers. Observing them using different wavelength facilities in the coming hours and...
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George Khorunzhev ((IKI RAS) SPACE RESEARCH INSTITUTE RUSSIAN ACADEMY OF SCIENCES)09/10/2024, 12:25Solicited
The four completed SRG Observatory half-year all-sky surveys have yielded a significant number of variable X-ray sources.
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The SRG/eROSITA telescope has discovered a rich population of tidal disruption events (TDE) that exhibit strong X-ray variability.
Searching for TDE in the X-ray band offers certain advantages over a selection in the optical range.
In X-rays, the background flux of the... -
Dr Lorenzo Amati (INAF - OAS Bologna)09/10/2024, 12:45Invited
The Transient High-Energy Sky and Early Universe Surveyor (THESEUS) is a mission conceptdeveloped by a large European collaboration under study by ESA since2018 and currently one of the three candidate M7 mission for a launch in mid '30s. THESEUS aims at fully exploiting Gamma-Ray Bursts for investigating the early Universe and as keyphenomena for multi-messenger astrophysics. By providing an...
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Prof. soroush shakeri (IUT, INO & ICRANet-Isfahan)09/10/2024, 13:15Regular
The Iranian National Observatory (INO) is poised to become a significant contributor to the global effort in monitoring and following up on transient astronomical events. With its 3.4-meter optical telescope strategically located in a low-density region of telescopes on Mount Gargash at 3600 m above sea level in central Iran, the INO offers a unique opportunity to fill critical gaps in the...
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Dr Paolo Soffitta10/10/2024, 09:30
X-ray Astronomy emerged in the early 1960s, and it quickly became evident that X-ray polarimetry would be crucial for interpreting data from celestial sources discovered thereafter. However, the experimental results from those early attempts were limited. On one hand, the sources were less polarized than expected; on the other, the sensitivity of the experimental techniques was still...
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Juri Poutanen10/10/2024, 10:10
The launch of the Imaging X-ray Polarimetry Explorer (IXPE) in Dec 2021 opened a new era in the study of compact astrophysical objects. For unresolved sources, polarimetry is the only way to learn about the source geometry. In this talk, I will highlight the progress made thanks to IXPE in understanding the geometry and physics of emitting regions in accreting black holes and neutron stars.
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Frederik Paerels10/10/2024, 10:40
The advent of gravitational wave astronomy has fundamentally changed our view of Black Holes, as far as their demographics are concerned. Likewise, the VLBI submm interferometric observations have finally directly shown us the relativistic distortions of spacetime close to a Black Hole. We may also detect neutrinos from extragalactic sources. I will argue that these novel observations nicely...
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Dr Kohta Murase (Penn State University)10/10/2024, 11:40Invited
The discovery of high-energy cosmic neutrinos opened a new window of astroparticle physics. Their origin is a new mystery in the field, which is tightly connected to the long-standing puzzle about the origin of cosmic rays. I will discuss theoretical implications of the latest results on high-energy neutrino observations, and demonstrate the power of multimessenger approaches. In particular, I...
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Sergey Troitskiy (Institute for Nuclear Research, Russian Academy of Sciences (RU))10/10/2024, 12:20Invited
While most of neutrinos can traverse the Earth, the sensitivity of high-energy neutrino telescopes varies significantly depending on whether the neutrinos are detected from above or below the horizon. The deployment of large-scale detectors in both hemispheres, such as Baikal-GVD and KM3NeT in addition to IceCube, is essential for full-sky studies of neutrinos across a wide energy range. I...
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Massimo Cappi10/10/2024, 14:40Invited
I will briefly review the current status of the NewAthena mission, with particular emphasis on its NewScience Performances for surveys and spectroscopic follow-ups
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Prof. Hu Zhan10/10/2024, 15:10Invited
The 2m-aperture China Space Station Telescope (CSST, also known as the Xuntian Space Telescope) is a major science project of China Manned Space Program. With a Cook-type three-mirror anastigmat design, the CSST can achieve superior image quality within a large field of view (FoV). It will be equipped with 5 first-generation instruments including a Survey Camera, a Terahertz Spectrometer, a...
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Prof. Wei Cui (Tsinghua University)10/10/2024, 15:40Invited
The field of X-ray astronomy has entered an era of spatially-resolved high-resolution spectroscopy, as driven by the technology of microcalorimeters. Through sounding-rocket experiments and the (brief) Hitomi mission in the past, the scientific potential of a microcalorimeter-based X-ray spectrometer is well illustrated and is highly exciting. All eyes are now on XRISM, with the expectation of...
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Dr Francesca Civano10/10/2024, 16:40Invited
The National Academies’ 2020 Decadal Survey in Astronomy and Astrophysics, Pathways to Discovery in Astronomy and Astrophysics for the 2020s recommended probe missions to be competed to accomplish the survey’s scientific goals. In particular, a far-infrared or an X-ray probe was recommended. In response to this, NASA posted the Astrophysics Probe Explorer Announcement of Opportunity (AO), to...
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Alexei Pozanenko (Space Research Insitute (IKI))10/10/2024, 17:10Regular
The LIGO-Virgo-KAGRA detectors have so far registered only 2 mergers of binary neutron stars GW170817 and GW190425. Based on the experience of searching and observing electromagnetic components of these mergers (GRB 170817 and GRB 190425), we consider the properties of these components in the gamma-range and discuss the possibility of registering electromagnetic components in the future.
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Tom McClain10/10/2024, 17:30Regular
Currently, parameter estimation schemes in gravitational wave astronomy fall into one of two wildly divergent categories: matched filtering schemes which rely on resource-intensive numerical modeling of full (strong curvature) general relativity or deep learning neural networks which rely on black box model training. The situation is only slightly improved for source localization algorithms,...
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Andrey Mukhin (Space Research Institute (IKI), Russian Academy of Sciences; Moscow Institute of Physics and Techonlogy)10/10/2024, 17:50flash talk
In this work, we studied X-ray source SRGe J021932.4-040154, that we associated with a single X-ray active star of spectral class G2V-G4V and the rotational period $P_{\rm rot} = 3.2 \pm 0.5$ days. The SRGe J021932 was observed with the SRG/eRROSITA during eUDS survey in 2019 in much dimmer state compared to the XMM-Newton catalogue 4XMM-DR12. Detailed analysis revealed that the archival...
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Valentin Nezabudkin (Space Research Institute, MIPT)10/10/2024, 17:55flash talk
The Nuclear Stellar Disk (NSD), along with the Nuclear Stellar Cluster (NSC) and the supermassive black hole Sgr A*, forms the central region of the Milky Way. Observations have well established that the Galaxy's X-ray emission is associated with the stellar population and predominantly arises from the integrated emission of accreting white dwarfs. This study focuses on the NSD emission in the...
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parisa hashemi (Isfahan University of Technology)10/10/2024, 18:00flash talk
Gamma-ray bursts (GRBs) are among the most explosive and brightest transient phenomena in the universe, occurring at cosmological distances. After decades of investigation, the origin of the jet composition, the radiation, and energy dissipation mechanisms of GRBs are among the most important open questions regarding the nature of the GRB central engine.
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Here, we consider the evolution of a... -
Sara Karimi10/10/2024, 18:05flash talk
The formation of heavy elements beyond iron in the universe has long been a subject of astrophysical inquiry, with the rapid neutron capture process (r-process) playing a critical role. Kilonovae, explosive events resulting from the merger of neutron stars, have emerged as key sites for r-process nucleosynthesis. This study explores the formation of heavy elements in kilonovae through detailed...
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SANTIAGO ALEJANDRO BERNAL (Instituto de Física y Astronomía, Universidad de Valparaíso)10/10/2024, 18:10flash talk
The origins of supermassive black holes (SMBHs) at the centers of massive galaxies are a topic of intense investigation. One way to address this subject is to identify the seeds of SMBH as intermediate-mass black holes (IMBHs; $100M_\odot < M_{BH} < 10^6M_\odot$). Given the observed relationship between the mass of a black hole and the mass of its host galaxy, IMBHs are expected to be found at...
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Dr Dmitry Fredreriks (Ioffe Institute)11/10/2024, 09:00Invited
For nearly 30 years, Konus-Wind has been a tireless workhorse for high-energy astrophysics.In this talk, we provide an overview and recent results from Konus-Wind observations of short, long, and ultra-long gamma-ray busts, Galactic and extragalactic magnetars, and solar flares. The recent results include the detection of giant flares from extragalactic magnetars, the famous SGR/FRB 200428...
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Evgeny Derishev (Institute of Applied Physics, RAS)11/10/2024, 09:30Invited
Recent observations of TeV emission from Gamma-Ray Bursts (GRBs)
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demonstrated with certainty that it belongs to the afterglow phase. Afterglows' emission from radio frequencies to GeV gamma-rays is of synchrotron origin, whereas the TeV component is produced via distinct physical process (inverse Compton). Thus, TeV observations open an entirely new window into physics of relativistic shocks.... -
Vikas Chand (Astrophysics Research Center of the Open University, Israel, Ra'anana)11/10/2024, 10:00Regular
A gamma-ray burst (GRB) afterglow is considered an orphan when it is detected without a targeted search triggered by the prompt GRB emission. This can occur when the GRB jet points away from us or if the prompt emission along our line of sight is dim (e.g. a ``dirty fireball''). We present a semi-analytic model for the afterglow lightcurves based on and calibrated with numerical simulations....
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Felix Mirabel11/10/2024, 10:20
Recent observations with the JWST and ALMA identified at z > 10 massive star forming galaxies of up to 1011 solar masses that are already quench at z > 3. This very early formation and rapid evolution of massive galaxies produced great surprise, because it is difficult to reconcile with standard $\Lambda$CDM predictions alone. I will show that BH feedback regulate the formation and evolution...
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Tatiana Larchenkova11/10/2024, 11:20
Cosmic objects with magnetic fields (quasars, AGNs) are observed at redshifts z≥7 and more (for instance, for z=10.073±0.002) indicates the early creation of magnetic fields. The observations of the cosmic telescope JWST show that the first galaxies were formed at redshifts z$\simeq$15 - 20. The early formation of galaxies creates favourable conditions for high impact of the Compton...
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Florian Kühnel11/10/2024, 11:40
Primordial black holes are black holes that may have formed in the early Universe. Their masses potentially span a range from as low as the Planck mass up to many orders of magnitude above the solar mass. This, in particular, includes those black holes recently discovered by LIGO/Virgo/KAGRA, and (part of) these may conceivably be of primordial origin. After a general introduction on...
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Levon Pogosian11/10/2024, 12:10
The Hubble tension hints at a missing ingredient in our model describing the universe around the epoch of recombination. A stochastic magnetic field, if present in the plasma prior to last scattering, would induce baryon inhomogeneities and speed up the recombination process, reducing the sound horizon at last scattering and potentially helping to relieve the Hubble tension. Intriguingly, the...
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Dmitry Gorbunov (Russian Academy of Sciences (RU))11/10/2024, 12:30
Brief overview and new results
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Sergei Grebenev (Space Research Institute)11/10/2024, 15:00
We show that Compton scattering by electrons of the hot intergalactic gas in galaxy clusters should lead to peculiar distortions of the cosmic background X-ray and soft gamma-ray radiation - an increase in its brightness at energies smaller than 60-100 keV and a drop at higher energies. In the cluster frame the maximum of the background decrease occurs at ~500-600 keV due to the recoil effect....
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Ilya Mereminskiy11/10/2024, 15:20Regular
The Mikhail Pavlinsky ART-XC telescope is ideally suited for sensitive wide-field X-ray surveys covering tens to hundreds square degrees per day. This allows us to search for new populations of X-ray transients, that are too weak to be discovered by all-sky monitors and too rare to be serendipitously found by other grazing-incidence mirror X-ray telescopes. Most of these transients are...
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Andrei Semena (Space Research Institute)11/10/2024, 15:40Regular
We describe the survey of the Galactic Bulge, performed by the Mikhail Pavlinsky ART-XC telescope on board the SRG observatory. In order to obtain the maximal sensitivity the special source detection algorithm was developed, which helped to reduce unusable areas around bright sources, populating the region. Using this algorithm a total of 172 point sources were detected. Of these, 153 are...
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Ilkham Galiullin (Kazan Federal University)11/10/2024, 16:00Regular
We report the study and characterization of two new eclipsing CVs (SRGeJ045359.9+622444 (SRGeJ0453) and SRGeJ041130.3+685350 (SRGeJ0411)) discovered from a joint SRG/eROSITA and ZTF program. These objects were identified as CV candidates in a crossmatch of a 1200 $\rm deg^2$ patch of sky of SRG/eROSITA X-ray data with Gaia proper motion data and the optical ZTF database. SRGeJ0453 and...
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Timur Mufakharov (Special Astrophysical Observatory of the Russian Academy of Sciences)11/10/2024, 16:45flash talk
We present a study of the radio properties of distant quasars at z$>$3. The complete sample consists of 101 objects with a flux density level greater than 100 mJy at 1.4 GHz selected in a declination range from -35° to +49°. The study based on simultaneous RATAN-600 observations at frequencies of 1.2, 2.3, 4.7, 8.2, 11.2, and 22.3 GHz in 2017-2020. The flux density measurements uncertainties...
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Dr Sreehari Harikesh (University of Haifa, Israel)11/10/2024, 16:50flash talk
Constraining the mass and spin of black holes is among the holy grails of contemporary research into accreting sources. Any image of a sufficiently optically thin source near a black hole exhibits contributions of extremely lensed light rays, which orbit the black hole due to its inexorable pull before travelling to the observer. In interferometric images like those produced by the Event...
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Aleksei Kruglov11/10/2024, 16:55flash talk
Temperature of the hot gas in galaxy clusters is known to be a reliable proxy for the their total gravitating mass, allowing one to use spectroscopic X-ray observations for halo mass function measurements. Data of shallow wide area surveys, however, often precludes direct fitting of the X-ray spectra, given possible biases arising due to unresolved (multitemperature) inner structure of the...
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Vladislav Barinov (INR RAS)11/10/2024, 17:00flash talk
In this talk we discuss constraints on the parameters of decaying sterile neutrinos as candidates for dark matter particles from the data of telescopes ART-XC and NuSTAR. We also discuss constraints that can be obtained from the data of these telescopes for annihilating dark matter.
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Eleni Antonopoulou (National & Kapodistrian University of Athens/ Academy of Athens)flash talk
The GRAVITY instrument made a remarkable observation during the Near-Infrared flares of 2018, detecting a fast-moving hot spot in what seemed to be a circular orbit around SgrA, the supermassive black hole in our Galactic Center. The Gravity Collaboration attempted to fit the observed flaring behavior with a circular Keplerian orbit, a few gravitational radii from the supermassive black hole....
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nurten ak (Dr.)Regular
We present the discovery of six low-redshift quasars, identified through spectral observations conducted with the RTT-150 telescope in Türkiye. With redshifts ranging from 0.3 to 0.6, these quasars were selected from candidates listed in the ROSAT survey catalog, focusing on those with i-band magnitudes brighter than 19.5. Our analysis includes detailed modeling of their continuum and emission...
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Shilpa Sarkar (Harish Chandra Research Institute (HRI))flash talk
We investigate accretion flows around rotating black holes (BHs) and obtain self-consistent transonic solutions in full general relativistic prescription. The flow is assumed to be viscous and radiative. Viscosity helps in the removal of angular momentum outwards, allowing matter to get accreted inwards. In addition, viscous heat dissipated makes the matter hotter. On the other hand, radiation...
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Mr Jorge García-Farieta (Universidad de Córdoba)flash talk
The new generation of galaxy surveys will provide unprecedented data allowing us to test gravity at cosmological scales. A robust cosmological analysis of the large-scale structure demands exploiting the nonlinear information encoded in the cosmic web. This study delves into the meticulous task of mapping modified gravity (MG) signatures within cosmic volumes by employing a large...
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Ernazar Abdikamalov (Nazarbayev University)Regular
Core-collapse supernovae are powerful explosions marking the end of massive star's lives. These events give birth to neutron stars and, in some cases, black holes. Despite extensive research, the intricate details of these explosions remain elusive. Strong gravitational waves (GWs) emitted during these events carry vital information about their origins. Detecting these waves could...
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Adi Nusser
The evolution of massive halos at high redshifts (z>9) is examined using constrained N-body simulations. The simulations are used to establish the relationship between the star formation rate and halo mass. A simple model based on the local (z=0) star formation is shown to account for the mildly elevated star formation rate at high redshifts.
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Vahe' Petrosian (Stanford University)Invited
AGN jets are detected via their radio and/or gamma-ray emissions while the accretion disks by their X-ray to IR radiation. The relation between these two mechanism can be investigated using broad band spectra of bright sources or through population studies, in particular the luminosity-luminosity (L-L) correlation at different wavelength for large samples of AGNs. In general, there is a large...
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Dr Maria Chira (IAASARS, National Obs. Athens)Regular
In this work we will scrutinize the universality of the well-known non-linear relation between the UV and X-ray luminosity of AGNs. The LX-LUV correlation provides insights on the energy generating mechanisms and structural characteristics of AGNs, but it has also been proposed as a cosmological probe, under the assumption that it is redshift independent. However, recent works on the subject...
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