Looking for Super-Massive Neutron Stars

Informations projet

LOVE-NEST

N° de convention de subvention: 101002352

DOI

10.3030/101002352

Date de signature de la CE 25 Mai 2021

Date de début 1 Decembre 2021

Date de fin 31 Août 2027

Financé au titre de

• EXCELLENT SCIENCE - European Research Council (ERC)

Coût total

€ 1 997 625,00

Contribution de l’UE

€ 1 997 625,00

Coordonné par

NORGES TEKNISK-NATURVITENSKAPELIGE UNIVERSITET NTNU
Norway

Periodic Reporting for period 2 - LOVE-NEST (Looking for Super-Massive Neutron Stars)

Période du rapport: 2023-06-01 au 2024-11-30

Résumé du contexte et des objectifs généraux du projet

What is the maximum mass that a neutron star can support before collapsing into a black hole?
Until recently the record was 2 Solar masses. Theory tells us that this limit cannot be much higher than 3 Solar masses. Knowing the answer has a major impact on gravitational wave astronomy and nuclear physics.

LOVE-NEST is focused on a new population of neutron stars in compact binaries known as “spiders”, because we have strong evidence that they harbor supermassive neutron stars.

The first goal is to find them by using optical photometry.

The second goal is to measure accurately their masses, using a new technique that our group pioneered.

The third goal is to model, simulate and understand the interaction between the relativistic pulsar wind and its surroundings.

The impact of LOVE-NEST will further reach:
• the nuclear physics community: the maximum neutron star mass depends on the microscopic interactions between particles in the core at densities of more than 1E15 g/cm3.
• the rising field of gravitational wave astronomy: the signal and outcome of a double neutron star merger depends on the maximum neutron star mass.

Travail effectué depuis le début du projet jusqu’à la fin de la période considérée dans le rapport et principaux résultats atteints jusqu’à présent

The main results of LOVE-NEST so far include:

-2022. X-ray variability disk state. Discovery of break frequencies in the X-ray power spectra of two transitional millisecond pulsars.

-2023. Irradiation in spiders: a broad view. Explained the dichotomy between two vs. one maximum in the optical light curves of spiders.

-2023. Found that the optical luminosity is correlated with the orbital period.

-2024. Revealed an invisible black widow undetected at all wavelengths except radio.

-2024. Found variable asymmetry and a new potential supermassive neutron star.

-2024. Found a face-on redback that mimicks a black widow.

-2024. Discovered new spider candidates.

Progrès au-delà de l’état des connaissances et impact potentiel prévu (y compris l’impact socio-économique et les conséquences sociétales plus larges du projet jusqu’à présent)

Expected results include:

-Precise measurements of another 3-4 massive neutron stars.

-New X-ray counterparts to black widow pulsars.

-Evolutionary tracks of compact binary millisecond pulsars, linked to their corresponding spin evolution.

-GR-MHD simulations of the disk state including for the first time radiative transfer.

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