SPOILER ALERT! We are in the year 2030 AD! So, if you do not wish to learn your future, you should stop reading now! Alright, for those of you who are still curious. Hundreds of new Supernovae have been detected. Structures in Supernova Remnants have shed light on particle acceleration, particle interactions and have also helped improve our understanding of diffusion. Powerful pulsars, both with and without surrounding wind nebulae (PWNe), have been detected on the Galactic plane shining light on the mystery of both magnetic fields and the evolution of such systems. Observations and theoretical work focusing on the closest supermassive black hole to Earth, Sgr A*, have yielded…
Read More >>Decelerating jets
I recently published my first paper in my Ph.D., focussing mainly on how jets accelerate from black hole accretion disks using first-principles general relativistic magneto-hydrodynamic simulations. It is an important question, how jets become relativistic, achieving high enough kinetic energy to affect the intergalactic medium upon collision. It turns out that the shape of jet matters a lot and that means, the ambient medium (i.e., the environment surrounding the black hole and the accretion disk) really needs to be evolved properly. Interestingly, when you evolve your simulation enough to give instabilities some time to work their magic, the jet begins to slow down. This slowdown happens because instabilities pick up…
Read More >>The journey of lights to a black hole
In today’s post, I would like to briefly talk about the features shown in the recent black hole image, and the efforts many people have paid for interpreting them. Someone would say that a black hole must be in the form of singularity, which makes it extremely difficult to prove its existence. However, over the decades, many theoretical works have been devoted to understanding the nature of the black hole and the effects of the general relativity; and providing the observational signatures that are expected. By the huge efforts of the international collaboration, the event horizon telescope (EHT) team has revealed the unprecedented image of the nucleus of the nearby…
Read More >>Jet launching in the black hole system MAXI J1535-571
Today I thought I would discuss results from my recent paper in ApJ (ArXiv link here). This paper presented results from a very long and comprehensive radio monitoring campaign of the black hole X-ray binary MAXI J1535-571 and included many people within the group. Using observations that I personally took with the Australia Telescope Compact Array (ATCA) (Figure 1), we were able to track the radio jet throughout the entirety of its 2017/2018 outburst. We found some very interesting and important results from this campaign. For the next part, you need to know that two types of jets are observed from black hole X-ray binaries. During lower accretion rates we…
Read More >>Sometimes, a star gets very unlucky…
Today I’ll be writing about the very first topic I ever did research in, during my Bachelor’s thesis: Tidal Disruption Events (or TDEs), or the most dramatic way in which a star’s life can end. Before getting into cool astrophysics stuff, let me remind you of how tides (roughly) work. Because of gravitation, the Moon attracts the Earth; however, because gravitation depends on the distance between two objects, points on the Earth that are closer to the Moon are attracted more, and vice versa. If the thing that’s being attracted isn’t solid – say, an Ocean – the result is that the Ocean gets deformed by gravity: In practice it’s…
Read More >>Helen Sawyer Hogg Prize Public Lecture in Montreal
I had the great honour last night of participating in an annual public lecture series put on by the Canadian Astronomical Society/Société Canadienne d’Astronomie (CASCA) and the Royal Astronomical Society of Canada. It was a pretty amazing thing to see my name on the same page as the prior speakers, many of whom have served as inspirations for me, like Vera Rubin, Dame Jocelyn Bell Burnell, and Fiona Harrison. This evening lecture for the public (though many scientists from the CASCA meeting also attended) was the first time I’d given a full hour public lecture, since normally most public talks are around 20 minutes, and it was a real pleasure…
Read More >>Unraveling a mystery in the Spanish Sierra Nevada
Very soon, in August, I will have the honor to visit and use a radio dish of 30 meter diameter on Pico Vileta in the Spanish Sierra Nevada, the IRAM 30-m telescope. I will be able to use it for unraveling a long-standing mystery related to an extremely energetic object within our own Galaxy. While I have been using radio-telescope data before, this is certainly something new and exciting for me. As observational astronomers, we are taking a lot of time submitting proposals to telescopes in order to eventually get to observe our desired object. In my case, these objects were mostly very massive black holes that are extracting gravitational…
Read More >>Can flaring blazars be the origin of high-energy neutrinos?
Time: 22nd of September 2017, 20:54:30.43 Coordinated Universal Time. Location: cold Antarctica. A suspect has just activated the alarm. The panicked guards are running from monitor-to-monitor searching for a trace of the suspect. Trained hounds are being released smelling the air for familiar clues. Within 43 seconds the news has spread to investigators all over the world. What you are reading is not a prison break scene but a very rare event. It’s the detection of a subatomic particle called neutrino from an experiment located a thousand meters beneath the Antarctic surface. Most likely, the scene didn’t evolve as I described above but it would have been extremely cool if…
Read More >>Black Holes’ Dining Table: thin or thick
An international team of the Event Horizon Telescope (EHT) project, including members from API, has announced the first results at the press conference on last Wednesday (Streaming link). The team has revealed the first ever image of the supermassive black at the heart of M87, a galaxy within the Virgo galaxy cluster, 55 million light years from Earth. This monumental image offers the glimpse of what is really going on near the event horizon, the point beyond which material (including light) never escape from the gravity of the black hole. By definition, a black hole itself is literally dark as it gobbles everything around it. However, under certain circumstances, it…
Read More >>Retreats in Academia – Team building?
Summary of the GRAPPA retreat – April 3-4 2019 Sera has organized several retreats for her group in the past. We usually bike to this picturesque farm in Weesp and spend the day in a meeting room surrounded by sheep. We use this meeting to focus and plan our research efforts, practice giving elevator/grant pitches, and discussing common challenges and how to overcome them. For a nice overview, see this excellent blog post by Tobi Beuchert. While I always thought that GRAPPA wasn’t running as smoothly as possible, I was doubtful of a “GRAPPA retreat”, but at the very least, I would finally get to know everyone. When I arrived…
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