Atelier API "Ondes gravitationnelles et objets compacts"

Session

Presentations

16 nov. 2023, 09:30

salle du château (Observatoire de Paris - site de Meudon)

9. Virgo and ET at Paris Observatory

Jérôme Novak (LUTH, CNRS - Observatoire de Paris)

16/11/2023 09:30

11. Observatoire numérique e-Novas

Raphaël Mignon-Risse (CNES/APC)

16/11/2023 09:50

5. Signatures of circumbinary disks around pre-merger binary black holes

Raphaël Mignon-Risse (CNES/APC)

16/11/2023 10:00

Despite the re-birth of multi-messenger astronomy, no unambiguous electromagnetic (EM) counterpart to binary black hole (BBH) pre-/post-merger has been reported. Detecting the EM pre-merger counterpart would allow for optimal follow-up. However, the accretion properties onto pre-merger BBHs and EM signatures are not firmly identified because few numerical codes are able to model accretion and...

8. A census of compact objects in Galactic X-ray binaries

Francis Fortin (IRAP)

16/11/2023 10:20

X-ray binaries are stellar systems that undergo mass transfer between a normal star and a compact object. They are ideal candidates to be the progenitors of double compact binaries that end up merging in a burst of gravitational waves. Evolutionary mechanisms such a supernova events or the common envelope phase have a crucial impact on the likelyhood of such binaries to merge in Hubble...

12. LISA at Paris Observatory

Adrien Bourgoin (SYRTE, Observatoire de Paris)

17/11/2023 09:30

13. KADATH

Philippe Grandclement (CNRS ; Observatoire de Paris)

17/11/2023 09:50

14. GRAVITY

Karim Abd El Dayem (Observatoire de Paris (LESIA))

17/11/2023 10:10

2. Relativistic effects on the orbit of the closest stars to the black hole at the center of the Galaxy

Karim Abd El Dayem (Observatoire de Paris (LESIA))

17/11/2023 10:20

In this presentation we investigate the detection of the angular momentum (or spin) and quadrupole moment of the black hole at the center of the galaxy called Sgr A*. These parameters affect the astrometric and spectroscopic observations of stars in the close vicinity of the black hole (S stars). Here, we consider a collection of S stars as well as a
putative star called S2/10 that is...

7. Study of photon rings in the images of black holes

Irene Urso (LESIA, Paris Observatory)

17/11/2023 11:10

The Event Horizon Telescope (EHT) collaboration released in 2019 the first horizon-scale images of the supermassive black hole M87*, dominated by a bright, unresolved ring. General relativity (GR) predicts that embedded whitin this images lie observable, thin, ring-shaped features produced by photons on extremely bent orbits: the "photon rings".
In a parametric framework of GR, the idea of...

1. Towards a more robust algorithm for computing the Kerr quasinormal mode frequencies

Sashwat Tanay (LUTH, Paris Observatory)

17/11/2023 11:30

Leaver's method has been the standard for computing the quasinormal mode (QNM) frequencies for a Kerr black hole (BH) for a few decades. We start with a spectral variant of Leaver's method introduced by Cook and Zalutskiy (arXiv: 1410.7698) and propose improvements in the form of computing the necessary derivatives analytically, rather than by numerical finite differencing. We also incorporate...

4. The gravitational-wave phase at 4.5PN

David Trestini (IAP et LUTH)

17/11/2023 11:50

The main observable for the detection of gravitational waves in general relativity generated by compact binary systems is the phase of the wave. Within the post-Newtonian approximation, where the objects are assumed to be well-separated and to have small velocities, one can obtain analytical expressions for the phase as a series in $(v/c)^2$. Before this work, the phase (as well as the...

3. ET-WST synergy for next generation multi-messenger observations

Sofia Bisero (GEPI, Observatoire de Paris, Université PSL, CNRS)

17/11/2023 12:10

The Einstein Telescope (ET) will be an innovative next generation gravitational wave (GW) interferometer. With ET it will be possible to detect thousands of binary neutron star systems mergers (BNS) per year, up to z>3. The corresponding electromagnetic (EM) counterparts will likely be faint and to be searched in the large error regions of ET GW signals. Beyond the detection, the bottle neck...

6. AGN interferometric observations to measure cosmological distances

Pierre Vermot (LESIA)

17/11/2023 12:30

The AGN MELBA project aims to construct a precise multi-scale and multi-wavelength model of nearby AGNs by combining various high angular resolution adaptive optics and interferometric observations. A crucial goal of this project is to enhance the "SARM method", which allows for the measurement of cosmological distances independently from classical methods.

I will provide an overall...

10. Welcome