Astronomy Centre

Anastasia Fialkov

The First Billion Years

 The first population of stars and black holes formed when the Universe was only few hundred million years old. Properties of the first astrophysical objects are highly unconstrained because, on one hand, it is very difficult to model the formation processes from first principles; on the other hand, the available observations are extremely scares and theory remains uninformed. However, this field is undergoing a revolution with many telescopes trying to probe the era of the first starlight. The 21-cm signal of neutral hydrogen is the most promising way to probe the first billion years of cosmic history. This signal is produced at the rest-frame frequency of 1.42 GHz, corresponding to the wavelength of 21 cm, and is sensitive to astrophysical processes such as star formation, heating and ionization of the gas. The 21-cm signal is also sensitive to the physical properties of dark matter particles, such as their mass, decay rate and/or scattering cross-section with baryons. Observations of the 21-cm signal are very challenging because the intrinsically weak cosmological signal is contaminated by strong foregrounds. Despite the challenges, the international astrophysical community is heavily engaged: pioneering experiments such as the Experiment to Detect the Global EoR Signature (EDGES), the Shaped Antenna measurement of the background RAdio Spectrum (SARAS), and the Large Aperture Experiment to Detect the Dark Ages (LEDA) are taking data; while the exploration of the early Universe via fluctuations in the 21-cm signal is one of the major science cases of the Square Kilometer Array (SKA), an international facility supported by twelve member countries including the UK and being constructed in Australia and South Africa.

 The research led by Fialkov tackles multiple challenges related to the field of 21-cm cosmology. Available PhD projects include analytical and numerical modeling of the signal, exploration of dark matter signatures, understanding of the foregrounds, applying advanced statistical methods (e.g., machine learning methods) to signal extraction and much more.


Expected signals

About me: I moved to Sussex in January 2019 as a Royal Society University Research Fellow. Previously I was a Senior Kavli Fellow at the Institute of Astronomy and Kavli Institute for Cosmology at Cambridge University. Before arriving to Cambridge I held the prestigious ITC Fellowship at the Harvard Center for Astrophysics (2015-2018) and the Junior Research Chair Fellowship at the International Center for fundamental physics at Ecole Normale Superieure, Paris (2013-2015). I have obtained my Ph.D. in November 2013 from the Tel-Aviv University, Israel. 

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