Astrophysique à Haute Energie

Searches for High-Energy Neutrinos from the Cygnus Bubble, Galactic Plane, and AGNs with Multi-Messenger Observations

High-energy neutrino and γ-ray emission are expected from the Galactic plane, produced by interactions between cosmic rays and the interstellar medium or radiation fields. Recent LHAASO observations have detected diffuse γ-rays from the Galactic plane and an ultrahigh-energy γ-ray bubble (Cygnus Bubble) up to PeV energies, suggesting the possibility of neutrino emission. Using 7 years of publicly available IceCube track data with the full detector, we conducted searches for neutrino signals correlated with LHAASO diffuse Galactic γ-ray emission and Cygnus Bubble using a template method.

Evolution of the Comptonizing medium of the black-hole candidate Swift J1727.8–1613 along the accretion state transition using NICER

Evidence for a strong connection between the X-ray corona and the radio jet in black hole X-ray binaries has grown significantly. During state transitions, the inferred corona size correlates with both the jet’s flux and its synchrotron spectrum properties, offering insights into jet acceleration mechanisms. We investigate the properties of the Comptonizing medium in Swift J1727.8-1613 using the time-dependent Comptonization model vkompth, with NICER observations of type-C QPOs in the hard and hard-intermediate states.

Be stars in binaries

In recent years, multiple lines of evidence have emerged supporting the idea that Be stars are mass gainers in interacting binaries. Together, these findings suggest a compelling scenario in which all Be stars are formed through binary interactions. Nevertheless, the broader implications of this scenario must be carefully examined within the context of massive binary evolution.

Thesis defence - Sruthi Ravikularaman

Dear all,

I am excited to invite you to my PhD thesis defence this Friday, 27 September, at 10 AM (see abstract below). It will take place at amphi Pierre-Gilles de Gennes and be followed by a pot in the hall de convivialité on the 4th floor. 

The presentation may also be followed on Zoom:  https://u-paris.zoom.us/j/84670020046?pwd=9QjjU3CKaKBwCtwLEkjbpEJjJ1Y6p9.1
(Meeting ID: 846 7002 0046, Passcode: 429346)

Hope to see many of you there!

Journée Belisama "Science et Art" le 28 mars 2024 à l'amphi Pierre-Gilles de Gennes

Chers collègues,

Nous organisons une journée autour du projet BELISAMA à laquelle vous êtes cordialement invités. Nous vous joignons la plaquette descriptive de cette journée. Le projet de science participative BELISAMA, qui vise à faire découvrir aux lycéens la radioactivité naturelle et les phénomènes produits pendant les orages, est décrit sur notre site Web: www.belisamaedu.fr.

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