Star formation and supernova explosions play an important role in galaxy formation and evolution, in a process known as feedback. Today’s astrobite discusses how modifying the amount of feedback from supernova explosions affects the properties of the disc of a Milky Way galaxy, and how it affects the hot, gaseous halo surrounding massive galaxies.
Supermassive black holes (SMBH) likely exist at the center of every massive galaxy in our universe. How these million to billion solar mass beasts form is not well understood. The authors in today’s astrobite examine the possibility of the direct collapse of massive gas clouds to form SMBH seeds in a computer simulation of a galaxy merger.
In this short critical essay, a computational astrophysicist, Kevin Heng, questions the movement of his field toward more complex models producing larger volumes of data. Toward the end of his essay, Heng poses some open questions to the simulation community. “Is scientific truth more robustly represented by the simplest, or the most complex model?”, and, “How may we judge when a simulation has successfully approximated reality in some way?”
High resolution computational simulations are a valuable means by which Astronomers test our understanding of the Universe, and make predictions. The world of computational astrophysics broke new ground recently with the highest resolution cosmological simulation to date, Illustris, making for some spectacular science and some spectacular images.
Imagine a spinning skater. She pulls her arms in a little and spins faster. She brings her arms all the way into her chest, and spins really fast, and then bam! she rockets up into the sky. Seven years ago, computer simulations revealed a configuration of two spinning black holes that merged in this way, jumping out of their orbital plane with a velocity of several thousand km/s. Not only is this weird, it’s also important. We know that large galaxies host supermassive black holes at their centers. We also know that galaxies merge, presumably introducing their black holes to one another. If the newly formed black hole were to exit the galaxy entirely, it could carry its accretion disk with it, and be observable as a displaced core.
Can life spread from Earth to the moons of Jupiter and Saturn on rock ejected from meteoroid collisions? The authors of this paper start on answering this question by asking if ejected material from Earth can even reach the gas giants’ moons. The answer is yes, so it’s possible that microbial Earthlings have already traveled a lot farther than human ones.