Current and future research interests

I am currently in the final year of my PhD studies at the University of Bucharest – Faculty of Physics, Atomic and Nuclear Physics, Elementary Particles, Astrophysics and Applications direction, with interest in Early Universe galaxy formation and the correlations between the linked evolution of the galaxies and their central black holes (BHs). I worked on mass determinations for massive black holes (MBHs), on generation of mass catalogs from extragalactic infrared (IR) observations and continued to N-body simulations in order to validate various scenarios for the first population of MBHs.

My undergraduate and graduate studies, before being accepted in the Doctoral School, had a more general approach to Physic in order to honor the local tradition (when looking at the college program there was clear emphasis on the nuclear part). Therefore, it is no real surprise that my first year in research was part of the Applied Nuclear Physics Department at the National R&D Institute for Physics and Nuclear Engineering “Horia Hulubei” (IFIN-HH), where I was hired as a Physicist. Once I completed my master’s degree, I decided that it was time to honor my initial motivation for starting my Physics studies and seek a doctoral programme in Space Science related subjects. With this in mind, I managed to obtain a temporary R.A. position at the Institute of Space Science (ISS) from Romania inside the High Energy Astrophysics and Advanced Technologies Laboratory. During that time, I was mostly involved with the European Space Agency’s (ESA) mission PROBA-3, where I studied orbital mechanics and contributed to the fullstack development stage of the mission’s website. I also had a brief interaction with the Gravity, Microgravity and Nanosatellites Group, where I participated in an ESA project that used Augmented Reality (AR) for training procedures (Augmented Reality System for Space Applications - ARSSA). There, my work included a programming part (using the Unity Engine) for creating the AR system menus, as well as a more documentational one (writing for the proposal’s technical requirements). But, more importantly, being part of the ISS offered me the opportunity to start my own research in MBHs under the direct coordination of the head of the Cosmology and Astroparticle Physics Laboratory, Dr. Laurențiu Caramete. At first, I was mainly assigned responsibility on mass determinations for MBHs that later established a basis for expanding the number of entries in IR observation derived catalogues present at that time.

In other words, after finishing the first drafts of the mass catalogues, that were presented at the 42nd COSPAR Scientific Assembly in Pasadena (California), and having received positive feedback from the community, I advanced to the merging and growth processes of MBHs, by using N-body code packages (like GADGET, GIZMO and, recently, nbody6/nbody6++). The whole purpose was to set up a framework where me and my advisor could try different scenarios for MBH growth. This meant low and high seed cases, but even hybrid ones. We placed these seed BHs at redshift ~ 7 and let them evolve for approximately 13 Giga-years, in order to compare our mass concentration results with the present-day distributions. We also wanted to compute merging rates for predictions regarding the LISA (Laser Interferometer Space Antenna) Space Mission.

An important mention is that, almost three years ago, I became a full member for the LISA Consortium, actively participating in the Science Working Group (Low-Latency Pipeline working package). For that matter, I have been lucky enough to take part in the forming of our own ISS Science Group (ISS-Sci), which “check listed” an impressive variety of researchers (that were specialized in areas ranging from theory to phenomenology and experimental physics; or being active in teaching at university level; or even managing consortiums). At that time, I was the only R.A. of the group, a situation that came along with some pressure, but presented a lot of learning possibilities in a relative short time interval (scientific and proposal writing related ones).

Inside the LISA Consortium, I took a great pleasure in joining and being part of the Early Career Scientists Group (LECS) and a vivid statement is the fact that I share the coordination of the group with two other chairs for this year’s mandate. The responsibilities are various (managing the LECS officers and representatives, maintaining constant lines of communications with the other working groups, representing the early career scientists’ needs in front of the Consortium, organizing events for job applications, funding, mental health, social activities, mentorship programs and so on).

I cannot overlook the fact that, although it is an entry-level contribution, I had the chance to write a small part of the LISA Astrophysics Working Group White Paper (in prep.). This was my first collaboration experience with an extended collective. Consequentially, I validated the fact the I really enjoy (and I will probably make one of my priorities) to write for reviews where my competence can be of service.

For the moment, I have two published articles regarding the MBHs first populations. The first paper was intended for setting up the simulation environment (code benchmarking, MBHs merging processes etc.) and trying to grow MBHs to the sizes and concentrations derived from current observations. That meant that the initial scenarios for the Early Universe (again, this is a relative term regarding MBH observations and it’s somewhere around redshift 7) involved only using BH seeds and no accretion material (thus no accretion method). An assumption was made regarding the high possibility of Eddington-limit accretion (that made up for one order of magnitude in our final mass values).

The second one focuses on both of the main growth processes (merging and accretion). Here are taken into consideration gas particles from giant molecular clouds (GMC) that contribute significantly to the evolution of the BHs. Therefore, no assumptions were used and accretion was part of the simulation run. These more complex situations allowed for indication of mass ratios and merging rates predictions in the conclusional part of the research.

I have already started running simulations and advanced scenarios, that will constitute the basis for a third article in this series (by adding situations that involve a “swallowing stars” process by the BHs). This is an exotic case, but interesting nonetheless due to the potential of rapidly growing the MBHs compared to accretion.

To summarize, at this point in my career, I plan to expand from the MBHs topic, but by no means excluding them as they are my main interest and I eagerly wish to include them in a more complex cosmological frame of thought. Another important aspect is that I plan to specialize in attracting grants and funding. One of the many reasons I joined LECS was indeed finding out more about these kinds of procedures from people that already went through that process. That is also another aspect of why I like to work close with my coordinator (Dr. Caramete being, in my point of view, a living proof that professionalism and work ethic are the two main ingredients in winning competitions and developing a fruitful scientific career).