International scientific conference

AGES — 2026

Active Galaxies and other issues of Extragalactic aStrophysics

The international conference "AGES. Active galaxies and other issues of extragalactic astrophysics" will take place on 20−24 April 2026 at St. Petersburg State University. The conference continues the traditions laid down by the conference on the problems of extragalactic astronomy held in recent decades in the Pushchino Radio Astronomy Observatory. AGES-2026 will bring together leading researchers and early-career scientists from around the world to discuss recent advances and emerging topics in extragalactic astrophysics.

Scientific Organising Committee:

• Chen Yanmei (Nanjing University, China)
• Fan Junhui (Guangzhou University, China)
• Ganus Irina (Government of SPb, Russia)
• Gupta Alok (ARIES, India)
• Dragana Ilić (University of Belgrade — Faculty of Mathematics, Serbia)
• Ivanchik Alexandre (Ioffe Institute, Russia)
• Ikhsanov Nazar (Pulkovo Observatory, Russia)
• Jorstad Svetlana (Boston University, USA)
• Moiseev Alexei (SAO RAS, Russia) — co-chair
• Reshetnikov Vladimir (SPbU, Russia) — co-chair
• Sazonov Sergei (Space Research Institute, Russia)
• Sil’chenko Olga (SAI-Moscow University, Russia)

Local Organizing Committee:
Chugunov Ilia
Karataeva Gulnara
Kostiuk Valeria
Morozova Daria
Mokshin Dmitry
Savchenko Sergei
Shishkina Ekaterina — chair
Zibinskaya Daria
Zozulya Victor

The pair balance model for relativistic shocks has been proposed to explain the spectra of gamma-ray burst afterglows and their temporal evolution. In this model, the observed radiation has two components: synchrotron and inverse Compton. The latter is the result of upscattering of synchrotron photons by relativistic electrons from the same population. Furthermore, the structure of the shock front is regulated by electron-positron pair production through the interaction of Compton photons with the synchrotron photons. In the saturation regime, the average energy of the radiating electrons adjusts to a value at which the power fraction of internally absorbed radiation reaches approximately 0.1, which corresponds to almost complete disappearance of the viscous jump. The predictions of the model agree well with existing observations of the broadband afterglow spectra of gamma-ray bursts.

An equilibrium configuration of shear flow in blazar jets can also be maintained via electron-positron pair production. An analytical solution to this problem is not yet known; however, it is possible to sample spectra across the entire parameter space of the synchrotron self-Compton model. It turns out that if only those spectra are selected for which the fraction of absorbed radiation equals 0.1 (as in the case of shock waves), a clustering of these spectra is observed. Two clearly distinct groups of spectra, which differ in their parameters, can be related to the observed spectra of GeV and TeV blazars. The fundamental difference between the groups lies in the way the high-energy photons (those that produce electron-positron pairs) are generated. For TeV blazars, these photons result from the Compton upscattering of synchrotron radiation, whereas for GeV blazars, they correspond to second Compton scattering—that is, they are produced by scattering photons that have already undergone one Compton upscattering.

The properties of jet structure, flux variations and occasional strong flares are important tools to deeply study the physical process in narrow-line Seyfert 1 galaxies (NLS1s), the population at the early stage of AGN evolution with low black hole mass and high accretion rate. We made VLBI observations in a gamma-ray NLS1 J2118−0732 and found that the core-jet morphology, significant flux variations, and beaming effect make J2118−0732 resemble a blazar, however with the old diffuse/extended emission indicated from the steep spectrum at low frequencies. We found six NLS1s with large scale jet at projected linear size of 100 up to 940 kpc by searching LoTSS images for the SDSS NLS1 sample. Our follow-up multi-wavelength observations with VLA and VLBA help us understand how these low-mass high-accretion-rate systems can produce jets over 100 kpc similar to the typical powerful jet launcher. We study the long-term radio variability of five gamma-ray NLS1s and find that they are highly variable radio emitters and that there are instances of contemporaneous flaring activity between the radio and gamma-ray bands. However, there are also cases of significant radio outbursts without gamma-ray counterparts. We present the discovery of a repeating partial TDE exhibiting dual flares within around 3 yr in a NLS1 AT2021aeuk, where the second flare results from a collision between the TDE stream and the inner accretion disk, triggering an optical flare while simultaneously partially destroying the X-ray corona. All these diverse results are summarized to help understand the general properties in NLS1s.

November 20, 2025 — First announcement
January 15, 2026 — Start of registration and reception of registration fees
February 15, 2026 — End of early reception fees
March 15, 2026 — abstract submission deadline and end of online registration fee payment.
We will notify the accepted talks soon after the deadline.
March 30, 2026 — final version of the program
April 20, 2026 — start of the conference

The conference proceedings are planned to be published in the journal "Moscow University Physics Bulletin. Series 3. Physics. Astronomy." The journal is included in all authoritative databases: Web of Science, Scopus, and the Russian Science Citation Index (RSCI). The journal has a sample LATEX file for articles submitted for publication. The electronic version of the article must be submitted in LaTeX format. 

The journal’s website

More details will be announced later.

Registration will open at January 15, 2026.

Registration fee for the foreign participants — 18 000 RUB, for the Russian participants early fee (before February15) is 10 000 RUB, regular fee (after February 15) is 12 000 RUB. Students and PhD students have 50% discount fee. Foreign participants may pay at the registration deck.

The registration fee is waived for keynote speakers.

The registration fee covers conference package, coffee breaks and welcome party. If you have financial difficulties, please contact us: ages.conf2026@spbu.ru

St. Petersburg is a popular tourist destination that offers a variety of convenient accommodations. Conference participants can choose and book their preferred hotel.

This section will be updated, and any new information will be included in future newsletters.

The conference will be held at Saint Petersburg State University (SPbU) in the magnificent city of Saint Petersburg, Russia’s scientific and cultural capital. SPbU is the oldest university in Russia. It was founded by decree of Emperor Peter the Great. Today, SPbU is the only Russian university to have marked its 300th anniversary. Over the course of its almost three-century history, the university has been home to thousands of prominent scientists, public figures, government officials, politicians, writers, artists and musicians. Notable figures include Dmitri Mendeleev, Alexander Popov, Ivan Turgenev, Pyotr Stolypin, Ivan Pavlov, Dmitry Mamin-Sibiryak, Vasily Dokuchaev, Alexander Blok, Mikhail Vrubel, Mikhail Glinka, Nicholas Roerich, Lev Landau and Leonid Kantorovich, to name a few. The opening of the conference and first day’s sessions will take place in the assembly hall of the historic SPbU campus on Vasilievsky Island, situated on the picturesque banks of the Neva River.

The conference is supported by the Pulkovo Observatory, a UNESCO World Heritage Site, and the Central Astronomical Observatory of the Russian Academy of Sciences. Conference participants are welcome to visit the observatory.
 
The weather in St. Petersburg can be capricious and changeable, but the end of April usually brings warmth and sunny days. Holding the conference in the heart of Saint Petersburg will enable participants to enjoy not only scholarly discussions, but also the opportunity to explore the city’s and Russia’s cultural heritage. Nearby museums and theatres include the Hermitage Museum, the Russian Museum, the Kunstkamera, Saint Isaac’s Cathedral, the Mariinsky Theatre, and many more.

We look forward to welcoming you to St. Petersburg, where science, history and culture converge!