Scholars 2009

2009 Past - Astrophysics, History of the Universe

Horesh Assaf

Personal Details:
Department of Astrophysics - Tel Aviv University

Title of Research:
“Gravitational Lensing Statistics in Galaxy Clusters”

Update December 2016

Personal webpage:

Progress report: 

Once I graduated and received my PhD from Tel-Aviv university, I moved to the US and became a postdoctoral researcher at the California Institute of Technology (Caltech).  At Caltech I decided to shift my focus during my postdoc to a new research field. Thus, at Caltech, I broadened my field of research to study transients in detail. To accomplish this goal I joined the Palomar Transient Factory (PTF). For the first time, I conducted numerous optical observations using large facilities such as the Palomar 5-m telescope and the Keck telescope, thus becoming an experienced observer. Subsequently I accepted the challenge to lead the radio-wave follow-up observing campaign within the PTF collaboration - a completely new skill, without prior experience. However, I quickly adapted and went through the training process required to become a radio astronomer.  Currently I am leading the radio observing effort in the PTF collaboration (using multiple approved programs at various observatories: the Very Large Array, the Combined Array for Radio Astronomy in Millimeter wave, the Australia Telescope Compact Array, and the Arcminute Microkelvin Imager). Since my PhD, I worked on a variety of projects, e.g.: § my work on SN2011dh constituted some of the earliest and systematic radio observations of a core collapse SN, and has a large impact on our understanding of this type of SN. In these studies I concluded that the blast wave largely deviates from equipartition - a result that has an impact on our understanding of shockwave physics. § I have undertaken the earliest and most sensitive radio observations of a Type Ia supernova to date (SN 2011fe). My analysis showed that a large subset of single degenerate models can be ruled out. § During my time at Caltech I initiated and led, together with Prof. Gregg Hallinan, a major novel effort to conduct a radio time-domain survey of “SDSS Stripe 82” with the VLA. As part of this work I mentored the student Kunal Mooley. He has now completed his PhD, and I am proud to say that the project that I have initiated and led became a major part of Kunal’s thesis and is now also published (this is the most advanced radio time-domain survey to date). Incidentally, the lessons learned through this work are used for planning the next generation VLA all sky survey (VLASS).

After three years at Caltech I moved back to Israel to become a senior postdoctoral research at the Weizmann Institute of Science. Since going back to Israel for my second postdoc, I have continued leading my own projects as well as continuing being lead radio observer for the PTF collaboration. Among my recent discoveries, made under my own programs, is the first and earliest detailed radio spectrum of the rare type of ultra-long GRBs. My research revealed that the radio spectrum is uniquely different from that of the regular long GRB population. Another first discovery is that of a late (months after detection) radio flare turn-on from a tidal disruption event. This discovery has major consequences for our understanding of TDEs. In addition to both my independent work and my PTF collaborative work, I was recently invited to join, based on my expertise and recent work, the ThunderKAT team which is the time-domain key project for the new radio telescope, MeerKAT. I am now leading the cosmic explosion work group (together with Ralph Wijers) in the ThuderKAT project.

I have also initiated a radio program with the PESSTO collaboration. PESSTO (the Public ESO Spectroscopic Survey of Transient Objects) is a 5 year ESO project (now in its final year) that obtains multiple-epoch optical spectra of supernovae. As PESSTO had been lacking a radio follow-up program. I proposed such a program to the collaboration and my proposal has been accepted by the PESSTO board.

Very recently, in October 2016, I joined the faculty at The Hebrew University of Jerusalem (HUJI). This was so far a purely theoretical group and my goal is to develop observational astronomy. I see it as my personal goal to develop the field of time domain radio astronomy in Israel - and to raise the future generation of Israel radio astronomers. I hope my current work will also pave the way for myself and for Israel to become official partners in the international Square Kilometer Array (SKA) project, the largest radio telescope array on earth. 

Horesh Assaf CV