The Fourth Gravi-Gamma-Nu Workshop

Session

Probing the science of AGNs with multimessenger observations

4 Oct 2023, 10:00

Gran Sasso Science Institute

33. NGC 1068 as a neutrino source and the emerging class of Seyfert galaxies

Chiara Bellenghi (Technical University of Munich)

04/10/2023, 10:00

Invited Talk

While the existence of a diffuse flux of high-energy astrophysical neutrinos has been established for over a decade, the sources of this signal still need to be discovered. Last year, the IceCube Collaboration reported evidence for TeV neutrinos from the nearby active galaxy NGC 1068 at 4.2 sigma. After the blazar TXS 0506+056, NGC 1068 is the second extragalactic neutrino source identified....

7. A multi-messenger view of NGC 1068

Paolo Padovani (ESO)

04/10/2023, 10:30

Invited Talk

I will present a comprehensive multi-messenger view of NGC 1068, the prototype
Seyfert II galaxy recently associated with high-energy IceCube neutrinos. Various
aspects of the source, including its nuclear activity, jet, outflow, and the
starburst region, will be analised in detail using a multi-wavelength approach.
I will also explore its gamma-ray and neutrino emissions to try to...

42. Search and characterization of massive black hole binary candidates

Massimo Dotti (Istituto Nazionale di Fisica Nucleare)

04/10/2023, 11:00

Invited Talk

Massive black hole (MBH) binaries are among the loudest expected sources of low frequency gravitational waves. The rate of MBH coalescences is still very uncertain, and EM observations of close MBH binaries have the potential to strongly reduce the current uncertainties. I will discuss the physical consequences of the presence of a binary on the surrounding gas, deriving the observational...

44. BBH coalescence - observations

Bence Kocsis

04/10/2023, 12:00

Invited Talk

45. Progress in understanding tidal disruption events using observations

Sjoert Van Velzen

04/10/2023, 12:30

Invited Talk

34. Tidal disruption event rates under the magnifying glass

Elisa Bortolas (Unviersity of Milano-Bicocca, Istituto Nazionale di Fisica Nucleare)

04/10/2023, 13:00

Invited Talk

A tidal disruption event (TDE) occurs when a star is destroyed by the strong tidal shear of a massive black hole (MBH). TDE detections can unveil otherwise dormant MBHs, and they constitute unique probes for constraining the MBH demographics, especially towards the low-mass end of the MBH mass function. In order to do so, it is fundamental to theoretically constrain the expected TDE rates...

35. X-ray quasi-periodic eruptions: a potential electromagnetic counterpart of extreme mass ratio inspirals

Margherita Giustini (Centro de Astrobiologia (CAB), CSIC-INTA)

04/10/2023, 13:30

Invited Talk

X-ray quasi-periodic eruptions (QPEs) are a new variability phenomenon observed around low-mass ($M_{BH} < 10^7\,M_{\odot}$) supermassive black holes. They appear as sharp and intense bursts of soft X-ray emission ($E < 2$ keV), that last about one hour and repeat quasi-periodically every few hours. Each QPE emits a luminosity of $10^{42-43}$ erg s$^{-1}$, typically one order of magnitude...

1. Orbital Motion in the Reference Frame of a Blackhole

Vladimir Yershov (Formerly Mullard Space Science Laboratory)

04/10/2023, 15:30

Contributed Talk

I compare two versions of the analysis of the gravitational wave signal GW150914 presented previously by the LIGO/Virgo collaboration (LVC). The first version was presented in 2016 by this collaboration along with their announcement of the first experimental detection of gravitational waves [1]. It was based on rigorous general-relativistic treatment of the coalescing two-body problem. The...

9. The fourth Data Release of the fourth Fermi LAT source catalog

Stefano Ciprini (INFN Roma Tor Vergata & SSDC ASI)

04/10/2023, 15:45

Contributed Talk

The new data release four (DR4) of the Fourth catalog of gamma-ray sources of the Fermi Gamma-ray Space Telescope Large Area Telescope (4FGL), is based on gamma-ray photons detected with energy between 50 MeV and 1 TeV, and accumulated during the first 14 years of the Fermi all-sky survey. The analysis methods are inherited from the first 4FGL catalog (8-year list), with several new features...

19. Search for dark matter lines in the energy spectra of Galactic gamma rays with 13.75 years of Fermi-LAT data

Mario Giliberti (Istituto Nazionale di Fisica Nucleare)

04/10/2023, 16:00

Contributed Talk

Although there is indirect experimental evidence on the existence of dark matter, the debate on its nature is still open. One class of possible candidates is represented by Weakly Interacting Massive Particles (WIMP).

Our galaxy is largely composed of Dark Matter. Assuming that pairs of WIMPs can annihilate to produce gamma rays, or that WIMPs can directly decay into photons, monochromatic...

20. Astrophysical clues of axion-like particles

Francesco Schiavone (Università degli Studi di Bari & INFN Bari)

04/10/2023, 16:15

Contributed Talk

Axion-like particles (ALPs) are a common feature in several extensions of the Standard Model, arising, for example, as a solution to the strong CP problem in quantum chromodynamics or as a prediction of string theories. Astrophysical and cosmological signatures of axion-like particles might be found in many observations, including gravitational wave spectra, but most importantly in the...

29. Follow-up of gravitational waves alerts with IACTs using Astro-COLIBRI

Mathieu de Bony (IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France)

04/10/2023, 17:00

Contributed Talk

Follow-up of gravitational wave alerts has proven to be challenging, primarily due to the large uncertainty on the localisation, which is often significantly larger than the field of view of most instruments. A smart pointing strategy significantly enhances the chance of rapidly observing the true position of the underlying compact binary merger event and so to detect an electromagnetic...

47. The most luminous AGN do not produce the majority of the detected stellar-mass black hole binary mergers in the local Universe

Niccolò Veronesi (Leiden Observatory)

04/10/2023, 17:15

Contributed Talk

Despite the increasing number of GW detections, the astrophysical origin of the Binary Black Hole (BBH) mergers detected by the LIGO and Virgo interferometers remains elusive. A promising formation channel for these BBHs is inside accretion discs around supermassive black holes, that power AGN. Investigating the spatial correlation between the positions of these potential host environments and...

38. A Luminous Relativistic Tidal Disruption Event Discovered by the ZTF Optical Survey

Igor Andreoni

04/10/2023, 17:30

Contributed Talk

Tidal disruption events (TDEs) are bursts of electromagnetic energy released when supermassive black holes (SMBHs) at the centers of galaxies violently disrupt a star that passes too close. TDEs provide a new window to study accretion onto SMBHs and may be associated with high energy neutrinos. In some rare cases, this accretion leads to launching of a relativistic jet, but the necessary...

31. Multi-wavelength studies of Cosmic Ray accelerators

Chiara Bartolini (Istituto Nazionale di Fisica Nucleare)

04/10/2023, 17:45

Contributed Talk

The study of cosmic-ray accelerators is done with a multi-wavelength approach which provides a more complete view of the physical phenomena that involve the acceleration of charged particles. Cosmic-ray accelerators are both galactic, for example Supernova Remnants, and extragalactic, for example Active Galactic Nuclei and Gamma-Ray Bursts. To get a larger sample of Galactic cosmic-rays,...