Research
My research interests lie in the field of observational astrophysics and cosmology, especially time domain astronomy. My research has showed the feasibility of searches for strongly lensed supernovae with ground-based facilities and resulted in the discovery of five of the most distant core-collapse supernovae with implications on the volumetric core-collapse rates to very high redshifts. It has furthermore showed the utility of supernovae for cosmological studies, by investigating the properties of the strongly lensed and very distant supernova. My current research also includes studying tidal disruption flares and searching for short gamma-ray bursts from supernovae induced by axion-like particles which are candidates for dark matter.
The list of my pubblications can be found here.
Projects financed by the Slovenian research agency (ARRS) :
2023-2025: BI-VB/23-25-005 - Bilateral collaboration with the Institute for Astronomy, University of Cambridge, UK. Project title: Exploring new frontiers in stellar physics and cosmology with supernovae and strong lensing (Raziskave v fiziki zvezd in kozmologiji z uporabo supernov in močnega gravitacijskega lečenja). P.I. Petrushevska.
BI-US/22-24-006 - Bilateral collaboration with the Space Telescope Science Institute (STScl), US. Project title: Unveiling the expansion of the Universe with a novel strategy: strongly lensed supernovae with the Roman Space Telescope (Razkrivanje širjenja vesolja z močno lečenimi supernovami z vesoljskim teleskopom Roman Space Telescope). P.I. Petrushevska.
2019-2022 - Z1-1853 Postdoc project , title "Unveiling the expansion of the Universe with strongly lensed supernovae (Razkrivanje širjenja vesolja z močno lečenimi supernovami). P.I. Petrushevska
BI-US/2019–2021 - Bilateral project grant with the USA funded by ARRS: Unveiling the nature of the dark matter with a novel strategy: search for short gamma-ray bursts from supernovae induced by axionlike particles; P.I. Petrushevska, Program coordinator in USA: Dr. Manuel Meyer at the Kavli Institute for Particle Astrophysics and Cosmology, Stanford University.
Strongly lensed supernovae
Gravitational lenses such as galaxies and galaxy clusters, can magnify the flux of background galaxies. These galaxies at high redshift can host supernovae which, thanks to the magnification boost due to lensing, can be observed, otherwise too faint to be detected by current telescopes. Under the right circumstances, the background galaxies may also have multiple images due to the strong lensing. Of particular interest is to detect lensed supernovae of type Ia, because of their standard brightness. They could help improve lensing models and, if multiple images are observed, the Hubble constant can be measured independently. You can read about my work on strongly lensed supernovae here.
It is quite exciting that just in recent years, we have detected the multiple images from gravitationally lensed Type Ia supernovae ( iPTF16geu , SN Zwicky, SN H0pe and SN Encore).
Luminous flares from the nuclear regions of galaxies
Thanks to the advent of large-scale optical surveys, a diverse set of flares from the nuclear regions of galaxies has recently been discovered. These include the disruption of stars by supermassive black holes at the centres of galaxies - nuclear transients known as tidal disruption events (TDEs). Active galactic nuclei (AGN) can show extreme changes in the brightness and emission line intensities, often referred to as changing-look AGN (CLAGN). Given the physical and observational similarities, the interpretation and distinction of nuclear transients as CLAGN or TDEs remains difficult. One of the obstacles of making progress in the field is the lack of well-sampled data of long-lived nuclear outbursts in AGN. In our recent work on PS16dtm, we studied a nuclear transient in a Narrow Line Seyfert 1 (NLSy1) galaxy which has been proposed to be a TDE candidate. There, we showed our multi-year spectroscopic and photometric study of PS16dtm, which can help us to better understand the outbursts originating in NLSy1 galaxies. Read here our recently published paper on PS16dtm.
In another study, led by Philip Wiseman from the University of Southampton, we reported the observations and the analysis of the most energetic non-quasar transient ever observed, AT2021lwx. It appeared in Guardian, BBC, Time, New York Times.
Artistic impression of detecting axions from supernova explosions with the Fermi satellite. Credit: Maedeh Mohammadpour mir.
Axion dark mater search
The nature of dark matter, the substance that accounts for more than 85% of all matter in the Universe, remains a mystery. Many theories predict that dark matter is made up from yet – undiscovered fundamental particles. A plethora of ground-based and space born experiments are looking for traces of these particles. Together with Dr. Manuel Meyer , we use explosions of stars outside of our Milky Way to search for a particular class of dark matter particles. Read here our press release or our paper published in Physical Review Letters.
Collaborations
I am a member of the following international collaborations:
2021 - present - ePESSTO+: advanced Public ESO Spectroscopic Survey for Transient Objects (active in the Tidal Disruption Events group)
2021 - present - LensWatch collaboration aimed at searching for lensed supernovae with targeted surveys of known strong-lensing systems.
2019 - present - Junior member of the IAU (International Astronomical Union)
2018 - present - Vera Rubin Observatory - active in the Dark Energy Science Collaboration.
2013 - 2017 - Intermediate Palomar Transient Factory. My responsibilities included searching for candidates as probable supernovae in the data, triggering telescopes from an international network, processing spectroscopic data in order to classify the candidates.
LSST@Europe5 conference, September 2023, organized by our group, University of Rijeka, University of Belgrade and Rudjer Boskovic Istitute. Read more here.
