Fantastic Beasts (and where to find them) Most galaxies on our universe seem to harbor, at their center, the amazing beast known as a supermassive black hole (to know more about black holes see my previous post here). What do we mean by word supermassive? Astronomers compare the mass of most objects in the universe with the mass of the most massive object in our vicinity, i.e., our sun. Supermassive black holes are millions to billions of times more massive than our sun. To put it simply, millions of our suns together would weigh as much as these beasts! For a nice visualization see this link. Light from the vicinity of…

As one of fundamental forces, gravity works its magic on the physics of the largest scales, helping us understand how celestial objects form and move. Sir Isaac Newton in the 17th century formulated a mathematical equation depicting the effect two objects have on each other by virtue of their mass. Newton’s theory successfully predicted the presence of Neptune and continues to guide us in solving high school mechanics problems, apart from describing gravitational forces relating to small masses with velocities much lower than the speed of light. With Albert Einstein’s revolutionary theory of general relativity (or just GR) in 1915, an entirely new view of the heavens was brought to…

Hi, readers. I am Doosoo Yoon, who recently has joined Sera’s group. Since I started my academic career in astronomy, I have strongly interested in performing numerical simulations to figure out how astrophysical phenomena can be interpreted. In my first post, I would like to briefly talk about some basic processes of computational astrophysics and mindset for building a Matrix-world, from several articles I’ve read. Conducting research with numerical simulation requires three main components: understanding of dominant physical processes for the problem of interest, programming them with numerical algorithms and utilizing maximum capabilities of the computers for the simulations (Elmegreen 2011). In fact, all theoretical equations need to be approximated,…

Given that our group has been growing significantly over the last years, annual group retreats are the ideal occasion to get to know each other better and talk about important topics that don’t necessarily find their way in usual working days. So, just recently, we spent a whole day at a beautiful little farm in the outskirts of Amsterdam called “Bomen op Locatie”. Surprisingly, the weather turned out to be amazing, even close to the end of the year, even in the Netherlands. While the whole village was still asleep, our arrival at the farm was immediately recognized by one of two little pigs that live a happy life on…

Supermassive black holes are powerful engines. A black hole with the mass of a million-10 billion times the mass of the Sun is fueled by gas surrounding it. A small fraction of these systems accelerate particles in a collimated outflow of plasma, called jet. Many questions about AGN jets remain unanswered: How are those jets launched? Which particles are accelerated in a jet? We know that electrons (and positrons) are in a jet, as we see linearly polarized synchrotron emission from these jets in the radio-X-ray wavelengths. Electrons in the magnetic field of the jet gyrate and produce the light we see. However, it is not clear whether protons are…

The first paper of my PhD thesis was accepted on Friday for publication on Monthly Notices of the Royal Astronomical Society, and it was posted on arXiv yesterday! If you’re interested in jets and how to be clever with data to learn more about them, check it out! https://arxiv.org/abs/1810.11341

For this blog I thought I would talk a bit about my favourite telescope (yes, I have one of those…). As Dimitris talked about last week, detecting high-energy radiation can be complicated. X-rays for example are blocked by the atmosphere, so if you want to look at astronomical sources emitting X-rays you need to put a satellite in orbit. Beyond that, building the proper optics for detecting X-rays in the first place is very complicated. What makes observing X-rays so much trickier than, for example, the visible light that our eye is sensitive to, is how much energy each X-ray carries. Being so energetic means that if you were to…

or How to detect high energy γ rays   Radiation is being produced all over the universe. This radiation can either be observed by detectors on the surface of the Earth or be absorbed by the atmosphere. As Figure 1 demonstrates, radiation at radio wavelengths and visible light can reach the terrestrial observatories located around the globe. However, infrared, X rays and γ rays cannot travel through the atmosphere and space satellites are required in order to detect them. Since the onset of space missions in the 60s and 70s, satellites have surveyed the whole sky from infrared energies up to GeV γ rays (1GeV = 10^9 eV). However, in…

This week we have had an exciting new result published in Nature. This was work led by Jakob van den Eijnden, a PhD student here at in Amsterdam, and included his advisor Nathalie Degenaar, myself, Rudy Wijnands and Juan Hernandez-Santisteban here in Amsterdam, as well as James Miller-Jones (ICRAR/Curtin University, Australia) and Greg Sivakoff (University of Alberta, Canada). And I thought this would be a perfect opportunity for a blog. Fig 1: Jets are observed from all types of accreting sources. Jets are observed from accreting objects throughout the universe. We see them from accreting black holes, white dwarfs, neutron stars, and even young stars (Fig 1). About the only place we…

In this blog-post, I want to share my experience in the field of science communication and give you my personal perspective of things. I would be very happy to receive your feedback. Maybe, you disagree with what I say? Maybe, I missed something in my discussion? Feel free to contact me (t.beuchert@uva.nl) or post a comment below. Who we should communicate with and why “Science communication” is a term that one can write a lot about. I think what is important is that we would like to bridge between the broad public and the scientific community as well as within the scientific community itself. That way, we can establish links…