Special Colloquium
Dr. Krishna Mohana Ammenadka	SCHEDULED

Xinjiang Astronomical Observatory (XAO), China

Active galactic nuclei (AGN) power some of the most luminous phenomena in the universe through accretion onto supermassive black holes, driving relativistic jets that shape their host galaxies and environments. Beyond their electromagnetic output, AGN are emerging as key targets for multimessenger astrophysics, both as candidate neutrino sources and as potential gravitational-wave emitters through coalescing supermassive black hole binaries. In this talk, I highlight the importance of observations from long-term multiwavelength (radio to gamma-rays) monitoring programs coordinated with the Fermi-LAT for understanding AGN jet physics, drawing on results from my studies of select blazars in the Fermi-LAT era, alongside the first data release of the quasi-Simultaneous Multiwavelength Monitoring of gamma-ray-loud AGN (SMMAN) program with the Nanshan 26 m radio telescope. I will further discuss how long-term multiwavelength variability can serve as a powerful diagnostic for identifying and characterizing close supermassive black hole binaries.

	Promotionskolloquium
Arunima Dutta	SCHEDULED

MPIfR

Globular clusters (GCs) are gravitationally bound, dense stellar systems that contain some of the oldest stars in our Galaxy. Owing to their extreme stellar densities and high rates of binary interactions, GCs have long been known as breeding grounds for millisecond pulsars (MSPs), a subset of rapidly rotating and highly magnetised neutron stars with exceptional rotational stability and millisecond spin periods. GC pulsars serve as precision probes of the structure, gas content, magnetic fields, gravitational potential, and dynamical history of their host clusters, while the exotic binaries formed within them provide unique laboratories for fundamental physics. In this thesis, I have studied fourteen known pulsars in the dense globular cluster NGC 1851, using data primarily obtained with the MeerKAT telescope, and derived their timing solutions and physical properties. The astrometric positions of the pulsars reveal a striking east–west bar-like alignment, which is also observed for X-ray sources and may be an outcome of mass segregation influenced by the rotation of the cluster. Two of the systems are particularly interesting: PSR J0514-4002A and J0514-4002E (hereafter, NGC 1851A and NGC 1851E). NGC 1851A is a 4.99-ms pulsar in a highly eccentric 18-day binary, containing a 1.39 solar mass pulsar and a 1.08 solar mass white dwarf companion, and its timing reveals evidence for an ongoing three-body interaction with another nearby star. The most exotic pulsar in this cluster is NGC 1851E, which consists of a 5.6-ms pulsar in a 7-day eccentric binary with a total mass of 3.89 solar masses, making it the most massive known pulsar–compact object binary to be known. Its companion has a mass between 2.09 and 2.71 solar masses, placing it in the compact-object mass gap and suggesting that it could be either a very massive neutron star or a low-mass black hole. In either case, this system provides an unprecedented laboratory for studying the formation and nature of compact objects and testing fundamental physics.

	Main Colloquium
Prof. Sirio Belli	SCHEDULED

University of Bologna

I will present recent studies based on JWST spectroscopy from the Blue Jay survey and other programs, revealing the widespread presence of multi-phase outflows in massive galaxies at 2 < z < 5. The unprecedented sensitivity of JWST allows us to study not only the ionized gas, but also the hard-to-detect neutral atomic phase, which is colder and carries substantially more mass than the ionized phase. Neutral outflows are particularly common in quiescent galaxies, which also host low-luminosity AGNs that can only be detected by JWST. These observations represent the first direct evidence that the rapid quenching of massive galaxies at z~2 and beyond is likely due to powerful AGN-driven outflows.