We conduct a comprehensive investigation of Type Ia supernovae (SNe Ia) spectroscopic properties, specifically focusing on the photospheric expansion velocity of their ejecta. We explore the distributions of normal-velocity and high-velocity groups, obtained from silicon spectral line, as well as their relationship with the environments in which they occur, the spatial distributions, and the global characteristics of host galaxies such as mass, metallicity, and age. The nature of the two velocity groups is currently a subject of active debate. The observed velocity distribution might result from distinct characteristics of SN Ia progenitors or explosion scenarios. Alternatively, this phenomenon may be attributed to the angular geometry of asymmetric explosions, wherein variations in ejecta velocity depend on the observer's viewing angle. In this talk, we will present our latest findings, which provide additional constraints on the progenitor systems of SNe Ia and shed new light on their explosion mechanisms.

Dr. Lilit Barkhudaryan, a researcher at the AANL Center for Cosmology and Astrophysics, and Anna Sahakyan discuss the following topics in the latest episode of the program "Science People":

🔹 How did Lilit choose the profession of an astrophysicist?

🔹 What issues exist between physics curricula in schools and universities?

🔹 How was the decision to pursue a scientific career made?

🔹 What scientific path has the young scientist followed?

🔹 How did she choose her narrow field of specialization?

(in Armenian)

Over the past decade, compelling evidence has emerged that supports the existence of multiple progenitor channels leading to Type Ia supernovae (SNe Ia). In this seminar, I will provide a brief overview of our current understanding of SNe Ia progenitor natures and explosion mechanisms. Among the different channels, SNe Ia originating from sub-Chandrasekhar mass carbon-oxygen white dwarfs (WDs) have garnered significant attention. In these systems, an initial helium shell detonation - fed by material accreted from a binary companion - triggers a secondary detonation in the core of the primary WD. This double-detonation scenario predicts a critical relationship between the progenitor system's age and the peak luminosity of SN: younger progenitors result in brighter SNe. I will present our latest findings that validate the predicted correlation. Our analysis focuses on the spatial distribution of nearby SNe Ia within their host galaxy discs, employing diverse methods to estimate progenitor (dynamical) ages. These methods include analysing the relationship between SNe photometric properties, such as light curve decline rates, and their vertical distributions in discs, as well as their distances from host spiral arms. Additionally, I will present our results on the characteristics of SNe Ia host populations in the context of the "star formation desert" phenomenon and beyond. Finally, I will detail the questions still open and provide some perspectives on future research, as the ongoing robotic telescope surveys and the forthcoming Vera C. Rubin Observatory promise to deliver a far larger spectroscopic and photometric sample of nearby SNe Ia, enabling more robust and precise analyses.

An overview of the research and researchers at the Center for Cosmology and Astrophysics (Alikhanian National Science Laboratory - Yerevan Physics Institute), who, with support from the Armenian National Science & Education Fund, are making significant advancements in the study of supernovae and their host galaxies.

(in Armenian)

Researchers at the Alikhanian National Science Laboratory (Yerevan Physics Institute), with support from the Armenian National Science & Education Fund, are making groundbreaking advances in the study of Supernovae and their host galaxies. This fundamental research focuses on understanding the origins and evolution of Type Ia and Core-collapse Supernovae. The team, led by Dr. Arpine Karapetyan, is analyzing the spatial distribution and properties of SNe within host galaxies, with particular attention to star formation and galactic dynamics. The researchers aim to shed light on the progenitor systems of these stellar explosions, offering new insights into the role of galactic structure in shaping Supernova events. These findings could also have significant implications for cosmology and astrophysics. This work highlights Armenia's contribution to international astrophysical research and strengthens collaborations with global scientific communities.

(in Armenian)

A short news report about our fundamental research on Supernovae at the Alikhanian National Science Laboratory (Yerevan Physics Institute).

(in Armenian)

Over the past decade, substantial evidence has emerged supporting the presence of diverse progenitor channels leading to Type Ia Supernovae (SNe Ia). Among these channels, there are SNe Ia originating from carbon-oxygen white dwarfs with sub-Chandrasekhar masses. These white dwarfs undergo detonation and explosion triggered by primary detonation in the helium shell, which has been accreted from a companion star. This double-detonation model predicts a correlation between the age of the progenitor system and the near peak brightness: the younger the exploding progenitors, the brighter the SNe Ia. Here, we present our recent achievements, demonstrating the validity of the anticipated correlation. To accomplish this, we studied the spatial distribution of nearby SNe Ia within host galactic discs and estimate the ages of their progenitor populations using various approaches, including the analysis of SNe light curve decline rates versus the vertical age gradients in discs, the distances from host spiral arms, and versus the stellar population properties in the star formation desert phenomenon and beyond.

An easy explanation of how stars of various masses, sizes, and temperatures live their lives. Some of them end their lives with a powerful explosion. These events are known as Supernovae. During the explosion, Supernovae eject some part of stellar bodies into the interstellar medium. This ejected material is already enriched by chemical elements formed within stars during their evolution. Newly born stars are partially formed from material that was ejected into the interstellar medium during the explosions of the previous generation of stars. Our Sun is also the result of such an interesting life cycle...

(in Armenian)

At the Byurakan Astrophysical Observatory (BAO), our team is conducting pioneering research on supernovae (SNe) and their host galaxies. As a key center for astrophysical studies in Armenia, our work aligns with international scientific standards and involves collaborations with experts around the globe. We focus on understanding the origins, behavior, and characteristics of different types of SNe. Our research explores the relationship between SNe and the structures within their host galaxies, such as spiral arms, stellar populations, and the galactic environment. This work is critical to uncovering the processes behind star formation, stellar evolution, and galactic dynamics. However, conducting high-level science in Armenia presents certain challenges. Overall, our team at the BAO is making meaningful contributions to astrophysics while navigating the difficulties of conducting world-class research within the constraints of a small, developing nation. Through persistence, collaboration, and dedication, we aim to continue elevating Armenia's role in the global scientific community.

(in Armenian)

In the interview, young scientists discuss pressing issues in the field, including the challenges of securing adequate funding for research and development in Armenia. They highlight the shortage of qualified scientific personnel in Armenian institutions and the need for better support systems to retain talent in the field. The conversation also delves into the broader obstacles faced by the scientific community, such as limited collaboration opportunities and insufficient public recognition of the importance of science.

(in Armenian)