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X-WR-CALNAME:Observing the Big Bang
X-ORIGINAL-URL:https://cosmology.nl
X-WR-CALDESC:Events for Observing the Big Bang
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DTSTART;TZID=Europe/Amsterdam:20210409T140000
DTEND;TZID=Europe/Amsterdam:20210409T170000
DTSTAMP:20260617T004239
CREATED:20210325T141720Z
LAST-MODIFIED:20210401T155122Z
UID:489-1617976800-1617987600@cosmology.nl
SUMMARY:Utrecht Spring 2021
DESCRIPTION:Utrecht\, April 9th. \nThis meeting will take place via remote connection. Here the information for connecting: \nTime: April 9\, 2021 02:00 PM Amsterdam Time \nJoin Zoom Meeting\nZoom Link\nMeeting ID: 843 3902 4566\nPassword: a149bz \n \n14:00-14:50 CET: Talk by  Enis Belgacem (Utrecht)  \nTitle:  Anisotropies and chirality of the GW background with pulsar timing arrays  \nAbstract: \n Gravitational waves affect the regularity of radiation emission from pulsars. Monitoring pulsar timing arrays (PTAs) gives access to very low GW frequencies and can provide informations on the properties of the stochastic GW background expected\, for instance\, from inspiraling supermassive black hole binaries. After a general introduction to the subject\, I will explain some recent advances in the characterization of the signatures imprinted by intensity anisotropies and circular polarization of the GW background on the timing residuals at PTAs\, obtained within a convenient harmonic space treatment. I will then discuss ongoing work on the comparison with previous studies in configuration space.  \n15:00-15:50 CET: Talk by  Marc Kamionkowski (JHU)  \nTitle:  The Hubble tension and early dark energy 
 \nAbstract: \n We have known since the late 1920s that the Universe is expanding.  However\, the expansion rate currently inferred from measurements of the cosmic microwave background now disagrees with that obtained from supernova measurements.   Over the past few years\, theorists have been exploring the possibility that this Hubble tension is explained by some new “early dark energy”: a new component of matter that may have been dynamically important several hundred thousand years after the Big Bang.  \n16:00-16:50 CET: Talk by  Georgios Valogiannis (Harvard)  \nTitle:  Testing gravity with cosmology: efficient simulations\, novel statistics and analytical approaches \n \nAbstract: \n The nature of the accelerated expansion of the universe is arguably the biggest open question in modern cosmology. One of the competing candidates for its explanation claims that what we observe might be the signal of a fundamental deviation from Einstein’s General Relativity (GR) at large scales\, instead of dark energy. Such a breakdown of the laws of gravity would however manifest itself in the observed clustering pattern of the Large-Scale Structure (LSS) of the Universe. In this era of precision cosmology\, the current and next stage of LSS surveys such as DESI\, the V. Rubin Observatory and Euclid will thus offer an unprecedented opportunity to perform precise cosmological tests of gravity. The optimal interpretation of this vast amount of upcoming data is\, however\, contingent upon our ability to make efficient and reliable theoretical predictions of LSS observables\, a task that proves to be particularly challenging in such modified theories of gravity (MG). In this talk I will discuss how we can overcome these challenges by utilizing a combination of analytical\, semi-analytical and hybrid simulation techniques\, as well as a suite of novel statistics that will allow us to comfortably differentiate between competing scenarios in future analysis pipelines.   \n17:00 CET:  social virtual borrel
URL:https://cosmology.nl/event/utrecht-spring-2021/
CATEGORIES:THC meeting
ORGANIZER;CN="Tomislav%20Prokopec":MAILTO:t.prokopec@uu.nl
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