Invited Speakers
 
|
Ivan AGULLO TALK: Loop Quantum Cosmology and the Cosmic Microwave Background ABSTRACT: Our current understanding of the early universe rests on general relativity, and therefore it excludes the earliest stages of cosmic evolution, when energy density and curvature invariants approach the Planck scale. This talk provides an overview of the way loop quantum cosmology can be used to extend our description of the cosmos to include the Planck era. This approach provides examples of effects that may have observational implications, both for the power spectrum of the cosmic microwave background and non-Gaussianity. These effects open a window to test the basic principles on which this approach to quantum gravity rests. 
|
|
Lorenzo AMATI TALK: Cosmology and multi-messenger astrophysics with Gamma-Ray Bursts ABSTRACT: Gamma-Ray Bursts (GRBs) are the most extreme and powerful emissions of electromagnetic radiation in the Universe. Since their discovery in the late '60s, they constitute one of the most fascinating and mysterious phenomena for modern science, with strong implications for several fields of astrophysics and fundamental physics. In this review, I will focus on the perspective key-role of GRBs for cosmology and multi-messenger astrophysics. Indeed, the huge luminosity, the redshift distribution extending at least up to z~10 and the association with the explosive death of very massive stars make long GRBs (i.e., those lasting up to a few minutes) potentially extremely powerful cosmological probes (geometry and expansion rate of space-time, "dark energy", early Universe). At the same time, short GRBs (lasting no more than ~1-2s) are the most prominent electromagnetic signature of gravitational-wave sources like NS-NS and NS-BH merging events, and both long/short GRBs are expected to be associated with neutrino emission. I will also shortly describe the THESEUS space mission project, aiming at fully exploiting these unique potentialities of the GRB phenomenon.
|
|
Masaki ANDO TALK: DECIGO : Gravitational-Wave Observation from Space ABSTRACT: Overview of a space gravitational-wave (GW) antenna mission DECIGO andits precursor mission B-DECIGO will be presented. In twenty years, 3rd generation ground-based detectors (ET and CE) and a space mission LISA would be in operational. A space mission B-DECIGO will have an original design to haveobservation frequency band around 0.1Hz, which is between the ground-based detectors and LISA. This provides us original science possibilities: sciences only by B-DECIGO or those by combinations with the other GW or electro-magnetic wave observations. DECIGO is the future and upgraded mission of B-DECIGO, with an ambitious scientific target to observe the background GWs from the early universe; it has a potential to observe a direct signal from inflation of the Universe.
|
|
Anne ARCHIBALD TALK: Does extreme gravity affect how objects fall? ABSTRACT: Galileo famously showed that all objects, no matter how massive, fall the same way. This is a key idea in Einstein's theory of gravity - but almost all other theories of gravity predict that a star with strong enough gravity should actually fall differently. We were recently able to test this: we compared a neutron star, with its incredibly strong gravity, to a white dwarf, and we found that they fell almost exactly the same way, as Einstein predicted.
|
|
Markus ARNDT TALK: Experiments to Probe Quantum Linearity at the Interface to Gravity & Complexity ABSTRACT: Quantum physics is probably the best-confirmed theory of nature, and yet a number of questions need to be solved: Why do we find a linear evolution in quantum mechanics not in the macroscopic world we live in? What is the role of complexity or gravity in the quantum-to-classical transition? Starting from the visualization of the wave-particle duality with molecules we have generalized this experiment to large scale matter-wave interferometry with mesoscopic objects in different experimental configurations with nanomechanical phase gratings and purely optical photo-depletion gratings. We were able to demonstrate the de Broglie wave nature of biomolecules, clusters and nanoparticles beyond 10’000 amu, composed of more than 800 atoms. What then prevents the preparation of Schrödinger cat states in our everyday lives? Many suggestions have been made my colleagues around the world: What is the possible role of decoherence or even dark matter, the relevance of spontaneous or gravity-induced wave function collapse. How does gravitational free-fall constrain the evolution? Can static gravity imprint phase shifts on matter-waves? I will discuss this in the context of the current macromolecule interferometry in the lab with a perspective on nanoparticle experiments on drop towers and on satellites, in the future.
|
|
Luc BLANCHET TALK: Post-Newtonian Theory and Gravitational Waves ABSTRACT: The gravitational wave detectors LIGO/VIRGO have discovered the signals generated by the coalescence of binary black holes and neutron stars. The theoretical and numerical works on the two-body problem in general relativity play a very important role when analyzing the gravitational wave signals. In this talk, we shall present the state-of-the-art on approximation methods in general relativity, and in particular discuss the latest developments in the famous post-Newtonian approximation.
|
|
Elisabetta CAVAZZUTI TALK: Gev LAT observations from GRBs and active galactic nuclei ABSTRACT: The Fermi Gamma-ray Space Telescope was launched 10 years ago, and since then it has observed the sky mainly in survey mode. In these years the main instrument on board, the Large Area telescope (LAT), has provided unprecedented results on Galactic and extragalactic science. Last year, the LAT collaboration released a catalog of sources detected at energies above 10 GeV, and many follow-up studies have been published. In the near future a new list based on 8 years of data above 50 MeV will be released, which is expected to contain more than 5000 sources. Among them, about a third remain unassociated, meaning that there is not a known counterpart at other energies. What are these gamma-ray sources? I will present a more in-depth look at them discussing their gamma-ray properties and possible interpretations. In this talk I will also show the huge mine of information contained in catalogs and concentrate on the extragalactic sources such as Active Galactic Nuclei reviewing the main recent results.
|
|
Paolo DE BERNARDIS TALK: What's next in Cosmic Microwave Background research. An experimentalist point of view. ABSTRACT:
|
|
Ralph ENGEL TALK: What have we learned about ultra-high-energy cosmic rays from the Pierre Auger Observatory? ABSTRACT: The Pierre Auger Observatory is the largest cosmic-ray detector for the measurement of ultra-high-energy cosmic rays. In this talk, a review of our current understanding of these particles will be given, emphasizing the progress made in recent years thanks to the data collected with the Auger Observatory. A number of unexpected observations has led to a new picture of ultra-high-energy cosmic rays with increasingly strong constraints on the properties of their sources and their interactions in the atmosphere. The talk will conclude with a discussion of the currently ongoing upgrade of the Pierre Auger Observatory, which will address fundamental questions that have emerged from the cosmic-ray observations made so far.
|
|
Heino FALCKE TALK: Imaging Black Holes now and in the future ABSTRACT: One of the most fundamental predictions of general relativity are black holes. Their defining feature is the event horizon, the surface that even light cannot escape. So far, we have never seen the event horizon, but this is about to change. Advanced computer simulations make clear predictions of how the shadow of black holes should look like and global interferometric radio observations with the Event Horizon Telescope are now trying to image the supermassive black hole in the center of our own Milky Way and the radio galaxy M87 for the very first time. To improve the imaging quality further more telescopes should be added to the array, in particular in Africa. The more distant future will belong to higher frequencies and space-based interferometry. The talk will give an overview of the ongoing research to image and simulate black holes, as well as of plans for future expansions.
|
|
FAbio GARGANO TALK: DAMPE and its latest results ABSTRACT:Dark Matter Particle Explorer (DAMPE), the first Chinese astronomical satellite, was launched into a Sun-synchronous orbit at an altitude of about 500 km on 17 December 2015. DAMPE is a high-energy particle detector optimized for observations of cosmic ray electrons and gamma-rays up to about 10 TeV. In this talk I’ll introduce the on-orbit performance of the detector, the calibration, and the latest results on cosmic rays and gamma-rays of DAMPE.
|
|
Francis HALZEN TALK: IceCube: Opening a New Window on the Universe from the South Pole ABSTRACT: The IceCube project has transformed a cubic kilometer of natural Antarctic ice into a neutrino detector. IceCube discovered a flux of neutrinos reaching us from deep in the cosmos, with energies more than a million times greater than those humans can produce with particle accelerators. These energetic neutrinos are astronomical messengers from some of the most violent processes in the universe. We will explore the IceCube telescope and the significance of the discovery of cosmic neutrinos—we even have a first indication where cosmic neutrinos originate. Alerted by IceCube on September 22, 2017, several astronomical telescopes pinpointed a flaring galaxy, powered by an active supermassive black hole, as the source of a cosmic neutrino whose energy exceeds 300 TeV.
|
|
Marc HENNEAUX TALK: The cosmological singularity ABSTRACT: The BKL analysis of the generic behaviour of the gravitational field near a cosmological singularity will be reviewed. Its modern reformulation in terms of Weyl groups of hyperbolic Kac-Moody algebras will be presented. The analysis will cover pure gravity in four spacetime dimensions, as well as higher dimensional models connected with extended supergravities.
|
|
Thomas HERTOG TALK: A smooth exit form eternal inflation ABSTRACT: 'Eternal inflation' refers to a regime deep into the phase of inflation in the early universe in which the quantum dynamics of fluctuations dominate the classical slow roll evolution. We argue that this means the classical theory of inflation breaks down in eternal inflation. We then review the program initiated by Hawking and others to develop a quantum model of inflation. In this approach, the exit from eternal inflation is the mechanism through which the quantum universe becomes classical. Finally we discuss a remarkable recent development in this program which employs gauge-gravity duality to compute the quantum amplitudes of different shapes of the exit surface from eternal inflation. The results indicate that eternal inflation does not produce an infinite fractal-like multiverse as the naive extrapolation of the classical theory of inflation suggests, but that the exit surface is finite and reasonably smooth.
|
|
Takaaki KAJITA TALK: Status of KAGRA and its scientific goals ABSTRACT: KAGRA is a project trying to observe gravitational waves with a 3km X 3km arm lengths laser interferometer. It is under construction in Kamioka, Japan. The unique feature is to use cryogenic mirrors to reduce the thermal noises. I will describe the status of the KAGRA project and its scientific goals.
|
|
Victoria KASPI TALK: Fast Radio Bursts ABSTRACT: Fast Radio Bursts (FRBs) are a newly discovered astrophysical phenomenon consisting of short (few ms) bursts of radio waves. FRBs occur roughly 1000 times per sky per day. From their dispersion measures, these events are clearly extragalactic and possibly generally at cosmological distances. One FRB is known to repeat and indeed has been localized to a dwarf galaxy at redshift 0.2. Nevertheless, the origin of FRBs, whether repeating or not, is presently unknown. In this talk I will review FRB properties as well as highlight efforts to find FRBs, including a new Canadian radio telescope, CHIME, that is predicted to make major progress on the FRB problem.
|
|
James LATTIMER TALK: The history of r -process ABSTRACT:
|
|
Jean-Luc LEHNERS TALK: No smooth beginning for spacetime ABSTRACT: I will discuss an obstruction for theories of the beginning of the universe which can be formulated as semiclassical path integrals. Hartle and Hawking’s no boundary proposal and Vilenkin’s tunneling proposal are examples of such theories. Each may be formulated as the quantum amplitude for obtaining a final 3-geometry by integrating over 4-geometries. The result is obtained using a new mathematical tool - Picard-Lefschetz theory - for defining the semiclassical path integral for gravity. The Lorentzian path integral for quantum cosmology with a positive cosmological constant is mathematically meaningful in this approach, but the Euclidean version is not. Framed in this way, the resulting framework and predictions are unique. Unfortunately, the outcome is that primordial gravitational wave fluctuations are unsuppressed. Consequences for inflation will also be outlined.
|
|
Hao LIU TALK: An independent investigation of gravitational wave data ABSTRACT: Given the evident importance of LIGO's discovery of gravitational waves, it is important to perform completely independent analyses of the strain data. This talk will describe the results of one such study. With focus on GW150914, the talk will include a critical discussion of the methodology appropriate for gravitational wave data analysis, a novel method for blind analysis, and new estimates of the degeneracies associated with extracted gravitational wave parameters.
|
|
Malcolm LONGAIR TALK: Ryle and Hewish: 50 and 100 Year Anniversaries [Radio Astrophysics and the Rise of High Energy Astrophysics] ABSTRACT: This lecture celebrates the 100th anniversary of the birth of Martin Ryle and the 50th Anniversary of the discovery of pulsars. They jointly received the 1974 Nobel Prize in Physics, the first in the area of astrophysics, for the implementation of aperture synthesis (Ryle) and the discovery of pulsars (Hewish). In fact, their interests strongly overlapped, one of the key papers on the implementation of Aperture Synthesis being co-authored by Ryle and Hewish. The details of the discovery of pulsars and the roles played by Hewish and Bell will be described. These key advances were at the heart of the dramatic rise of high energy astrophysics and the realisation that general relativity is central to the understanding of high energy astrophysical phenomena.
|
|
Jun LUO TALK: TianQin: a space-borne gravitational wave detector ABSTRACT: TianQin is a proposal for a space-borne detector of gravitational waves in the millihertz frequencies. The experiment relies on a constellation of three drag-free spacecraft orbiting the Earth. Inter-spacecraft laser interferometry is used to monitor the distances between the test masses. The experiment is designed to be capable of detecting a signal with high confidence from a single source of gravitational waves within a few months of observing time. With such sensitivity, TianQin is able to detect gravitational waves from a plethora of sources and is able to provide key information to answering important questions in astrophysical and fundamental physics. In this talk, I will introduce the current status of the mission.
|
|
Razmik MIRZOYAN TALK: Gamma-Ray and Multi-Messenger Highlights with MAGIC ABSTRACT: Abstract. In this report we want to reflect on most recent highlights from the MAGIC collaboration, who is operating twin 17m diameter imaging air Cherenkov telescopes on the Roque de los Muchachos observatory on the Canary island of La Palma. These include news on measuring gamma-ray pulsations from source candidates above the threshold energy of 20-30 GeV, spectrum measurements of a steady source at a very low threshold and at the highest energy end of the spectrum, about the diffuse emission from the direction of the galactic center and number of other interesting results. Also, we want to dwell on the recent multi-messenger observation of extremely high energy neutrino by IceCube and gamma-ray emissions from the direction of the Bl-Lac object TXS0506, offering a physical interpretation scenario and linking the measured emissions to the extremely high energy cosmic rays in the jets of AGN.
|
|
Jeremiah OSTRIKER TALK: Ultra-light scalars as cosmological dark matter ABSTRACT: The nature of the primary constituent of cosmological dark matter remains unknown. The Cold Dark Matter ("CDM") paradigm fits all high redshift and all large- scale observations with accuracy, but on scales of several kpc or less the CDM model runs into difficulties, and direct detection of CDM particles has been without success. However, if the dark matter is comprised of ultra-light bosons with mass of roughly 10-22 eV and de-Broglie wavelength typically of order 1kpc, all large-scale phenomena are the same as with CDM but small-scale problems are alleviated in this model which is sometimes called Fuzzy Dark Matter ("FDM"). Low mass halos and galaxies are less abundant, alleviating the "two big to fail" galaxy problem and the absence of dark matter cusps is understood as well as other dynamical issues in low mass systems. Tests based on the Lyman-α forest and delayed high redshift galaxy formation will provide critical means to evaluate the FDM paradigm.
|
|
Lyman PAGE TALK: Measuring the Cosmic Microwave Background ABSTRACT: The cosmic microwave background (CMB), the faint afterglow of the Big Bang, is a powerful probe of the cosmos. From its study, we have learned the age of the universe, its major constituents, and characterized the fundamental fluctuations in gravity that gave rise to cosmic structure. After an introduction to the CMB and how to think about it, I will give an overview of the current observations. The desire to measure the CMB ever more precisely has driven the development of extraordinary detectors and techniques which I'll also briefly review. Lastly, I'll consider what we might hope to learn from the CMB in the next decade, including detecting, if they exist at sufficient amplitude, gravitational waves from the birth of the universe.
|
|
Malcolm J. PERRY TALK: Black Hole Entropy and Soft Hair ABSTRACT: The uniqueness theorems showing that black holes are described by their mass, angular momentum and electric charge have recently been shown that they are in need in modification in the light of recent developments in infrared physics. Black hole admit "soft hair" that can retains some of the information about their fromation. I will show how this hair is related to the Hawking entropy of black holes. This gives ways in which might develop a better of nderstanding of the information paradox.
|
|
Elena PIAN TALK: Kilonovae: the cosmic foundries of heavy elements ABSTRACT: The gravitational wave event following a binary neutron star merger and detected by the Ligo-Virgo interferometers on 17 August 2017 was a watershed for multi-messenger astronomy, until then only based on MeV neutrinos detected from the Sun and SN1987A, and on the possible association of few ultra-high neutrinos with multiwavelength outbursts of blazar-type AGNs. As predicted by theory, the optical/infrared electromagnetic counterpart of the compact binary merger is a radioactive source produced by isotopes of elements heavier than iron, nucleosynthesized during the coalescence via rapid neutron capture process. This detection opens up not only a new perspective for multi-messenger exploration, but also a pathway into the history of cosmic chemical enrichment.
|
|
Tsvi PIRAN TALK: Mergers and GRBs: past present and future ABSTRACT: The observed GRB (170817A) that followed GW170817 confirmed the longstanding prediction of association of short GRBs with neutron star mergers. The unique large scale observational campaign that followed provided numerous surprising observations. I discuss past predictions, current observations and their implications and future prospects of joint detection of GRBs and GW signals. Among the latter, most exciting is the possibility that the gravitational waves observations will teach us about the inner working of GRBs central engine and the acceleration process of relativistic jets.
|
|
Jean Loup PUGET TALK: The Planck mission ABSTRACT: The Planck mission of the European Space Agency has measured the Cosmic Microwve Background (CMB) coming from the early universe with unprecedented accuracy in intensity and polarization. It involves technologies flown for the first time in space for the detectors and the cryogenic chain. The Lambda-Cold Dark Matter model based on général relativity and the présent knowledge of particle physics has only 6 parameters to be determined from the observations. The mission was launched in 2009 and the Planck collaboration will release the final data to the scientific community this summer together with the papers describing the analysis. The polarization data have been now use fully and are in excellent agreement with the cosmolgical model derived from the intensity. The inflation paragdigm is now tested for three of its generic prédictions with High accuracy. Tighter contraints on physics (for ex on neutrinos masses) have been obtained. Nevertheless there are tensions with cosmological parameters from astrophysical measurements. These will be discussed.
TALK: From Planck to Atacama Cosmology Telescope ABSTRACT:
|
|
Ernst Maria RASEL TALK: Science Fiction turns into Reality: Interferometry with Bose-Einstein Condensates on ground and in space ABSTRACT:
|
|
Elisa RESCONI TALK: Neutrino Astronomy in the Multi-messenger Era ABSTRACT:
|
|
Manuel RODRIGUES TALK: The first results of the MICROSCOPE test of the equivalence principle in space ABSTRACT: On April 25th, 2016, a new CNES laboratory, MICROSCOPE, was launched into space to test the (weak) equivalence principle (WEP) with an unprecedented sensitivity of 10-15sup>. On board, the scientific payload TSAGE developed by ONERA has been collecting for 2 years more than 107 seconds of precious data. In December 2017, a first result based on 10% of the current available data was published showing no detectable violation up to 2x10-14. After a brief presentation of the mission, we will focus on the method to establish the assessment of systematic and stochastic errors. Different configurations of the satellite and of the payload were used to establish the sensitivity of the experiment to the environment. The analysis of these characterization sessions will help to better evaluate the systematic errors whereas of additional science data will help to decrease the impact of stochastic errors. A status of the science with MICROSCOPE will conclude the presentation.
|
|
Stephan ROSSWOG TALK: Neutron star mergers as heavy element production site ABSTRACT: Neutron star mergers had long been suspected to produce gravitational wave "chirps", gamma ray bursts and produce r-process elements. While overall convincing, all these conjectures were based on indirect arguments and none was proven directly. This changed on August 17, 2017: a gravitational wave signal from a merging neutron star binary was detected, closely followed by a short burst of gamma-rays and week-long transients across the electromagnetic spectrum coming from the radioactive decay of freshly synthesised r-process elements. In this talk I will give an overview over these recent events with a particular focus on the production of heavy elements.
|
|
Jorge Armando RUEDA HERNANDEZ TALK: Binary-driven hypernovae and the understanding of gamma-ray bursts ABSTRACT: The increasing quality and amount of data from both short-duration and long-duration gamma-ray bursts (GRBs) at different wavelengths has allowed to perform detailed data analysis challenging theoretical models for their explanation and pointing to a crucial role of up to seven type of compact-object binaries for their understanding. I focus in this talk on long GRBs associated with supernovae (SNe) and show how they can be understood as originated in tight (few minutes period) binary systems composed of a carbon-oxygen (CO) core and a neutron star (NS) companion. The SN explosion of the CO core triggers a hypercritical (i.e. highly super Eddington) accretion onto the NS companion inducing its gravitational collapse to a black hole (BH). The accretion process, the BH formation, the SN and the complex interaction among these process, including the transition from the SN into a HN by such an interaction lead to specific signatures observable in GRB lightcurves and spectra. We have coined the term binary-driven hypernovae (BdHNe) for these systems. Results from 1D to 3D simulations of the above processes and their role in leading to a detailed BdHN morphological structure crucial in the GRB analysis are shown.
|
|
Remo RUFFINI TALK: The essential role of the nature of the binary progenitors for understanding Gamma-Ray Bursts ABSTRACT:
|
|
David SHOEMAKER TALK: LIGO's past and future observations of Black Hole and Neutron Star Binaries ABSTRACT: The LIGO instruments made the first observation of gravitational-wave strain as a function of time just shortly after the last Marcel Grossman meeting in 2015. Since that time a number of other black-hole binaries have been observed, bringing an unexpected class of stellar-mass black holes into our vision of the cosmos. More recently, in 2017, LIGO and Virgo together observed a neutron star binary, with a very fortunate set of conditions allowing a deep and broad electromagnetic followup. This talk with give some insights to the experimental and observational side of the story, and also give a roadmap for LIGO's future.
|
|
Rashid SUNYAEV TALK: The physics and observations of the Kinematic effect (kSZ) ABSTRACT:
|
|
Nial TANVIR TALK: A new era of gravitational-wave/electromagnetic multi-messenger astronomy ABSTRACT: The electromagnetic (EM) detection of events that are also detected as gravitational wave (GW) sources has long been a "holy grail" of astrophysics. Combined detection allows determination of redshifts, nucleosynthetic yields and characterisation of galactic environments and the linking of these to source properties derived from the GW signal. This ambition was finally realised in August 2017 with the discovery of the binary neutron star merger GW170817 by LIGO/Virgo, and the subsequent detection of its kilonova/macronova counterpart across the EM spectrum. The event also gave rise to a flash of gamma-rays and a late-time synchrotron signal indicating a relativistic component of the explosion. I will review what we have learnt from this event, particularly regarding the UV/optical/IR kilonova emission, and consider the future of this new field.
|
|
Jo VAN DEN BRAND TALK: Gravitational wave science and Virgo ABSTRACT: The LIGO Virgo Consortium achieved the first detection of gravitational waves. A century after the fundamental predictions of Einstein, we report the first direct observations of binary black hole systems merging to form single black holes. The detected waveforms match the predictions of general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. Our observations provide unique access to the properties of space-time at extreme curvatures: the strong-field, and high velocity regime. It allows unprecedented tests of general relativity for the nonlinear dynamics of highly disturbed black holes. Last year the gravitational waves from the merger of a binary neutron star was observed. This discovery marks the start of multi-messenger astronomy and the aftermath of this merger was studied by using 70 observatories on seven continents and in space, across the electromagnetic spectrum. The scientific impact of the recent detections will be explained. In addition key technological aspects will be addressed, such as the interferometric detection principle, optics, and sensors and actuators. Attention is paid to Advanced Virgo, the European detector near Pisa that came on-line last year. The lecture will close with a discussion of the largest challenges in the field, including plans for third generation detectors such as Einstein Telescope, an underground observatory for gravitational waves science.
|
|
Stefano VITALE TALK: Gravitation Wave Astronomy in ESA science programme ABSTRACT: The talk will review the status of GW astronomy within ESA Science Programme, from the results from LISA Pathfinder to the development of LISA.
|
|
Yu WANG TALK: On the role of binary systems in GW170817/GRB170817A/AT2017gfo ABSTRACT:
|
|
Tobias WESTPHAL TALK: Micro-mechanical measurements of weak gravitational forces ABSTRACT: We are motivated by the question how well one can isolate gravity as a dominant coupling force between small-scale physical systems in table-top experiments. In other words: how small can one make a gravitational source mass and still detect its gravitational coupling to a nearby test mass? We have recently introduced a micromechanical method that should allow for a proof-of-concept demonstration for objects on the scale of millimeters and tens of milligrams, which already improves the current limit for sensing the gravitational field of a small source mass by three orders of magnitude. With further improvements this method provides an alternative high-precision measurement of the gravitational constant, which may be less subject to conventional source-mass related disturbances of other approaches. In the long run, the ability to extend the control over gravitational coupling into the microscopic domain may enable a new generation of quantum experiments, in which the source mass character of the quantum systems start to play a role.
|
|
Shing-Tung YAU TALK: Quasi-local mass at null infinity ABSTRACT: An observer of an astronomical event is situated at the future null infinity, where light rays emitted from the source approach. But what can we measure at null infinity? There have been important work such as the Bondi mass loss formula and the nonlinear memory effect. In the talk, I shall discuss new results about the limit of quasilocal mass at null infinity. This is based on joint work with Po-Ning Chen, Ye-Kai Wang, and Mu-Tao Wang.
|
|
Bing ZHANG TALK: From gamma-ray bursts to fast radio bursts: unveiling the mystery of cosmic bursting sources ABSTRACT: After 50 years of observations and theoretical modeling, the mystery of gamma-ray bursts (GRBs) is finally solved following the joint detection of GRB 170817A associated with the NS-NS merger event GW170817. Eleven years ago, another type of mysterious cosmic bursting source, fast radio bursts (FRBs), was discovered. The journey towards unveiling the mystery of FRBs has been astonishingly similar to that for GRBs. Like detectives, we are in the process of collecting clues to identify the crime scene. In this talk, I will briefly summarize our understanding of GRBs (with the focus on the GRB 170817A) and review the current observational progress and theoretical efforts in understanding FRBs.
|
|
Shu ZHANG TALK: Introduction to Insight-HXMT: China’s first X-ray Astronomy Satellite ABSTRACT: Insight-HXMT is China's first X-ray Astronomy Satellite launched on June 15th, 2017. It carries three sets of collimated X-ray instruments, covering energy ranges of 1-15 keV, 5-30 keV, and 20-250 keV, respectively. In addition, it can serve as a nearly all-sky monitor for high energy sources between 0.2 to 3 MeV, such as bright pulsars and gamma-ray bursts. The performance verification (PV) and calibration program has finished in November 2017 and the regular science observation program has has been on going. In this talk, I will describe the instrumentation of Insight-HXMT, its in-orbit performance and some early results, including the Galactic plane scanning survey, black holes, pulsars, gamma-ray bursts, etc.
|