Wednesday Colloquium


"Probing the nature of Dark Matter and Dark Energy: from the Local Group to the Local Universe"

Wojciech Hellwing (Durham University)

Cosmology asks fundamental questions about the structure and composition of the Universe, its birth, evolution and future fate. The current understanding is encapsulated in a well established concordance cosmological model, the LCDM (Lambda Cold Dark Matter) model, whose parameters have been measured to remarkable precision. Nonetheless, the current cosmogony is characterized by several fundamental puzzles about the physical nature of the Universe. The most important questions concern the nature of the two components that dominate the evolution and fate of the Cosmos: Dark Matter (DM) and Dark Energy (DE). In my talk I will discuss my research focusing on possible ways of extracting the information about the physical nature of the DM and DE components using observations of the Local Universe (LU). Our cosmic neighbourhood stretches from the “backyard” dwarf galaxies of the Local Group (LG) to the relatively nearby galaxies woven into the Cosmic Web extending up to hundreds of Megaparesecs around us. The main topic of my talk will be twofold: (i) how we can explore the information encoded in the peculiar motions of local galaxies to study the nature of the DE and gravity; (ii) and how we can use the connection between the larger-scales and the local neighbourhood to get insights into the physical nature of DM and LCDM specific characteristics of galaxy formation.


"Simulations of Optically Thick Accretion onto Black Holes - The Power of Radiative Jets"

Aleksander Sądowski (MIT Kavli Institute for Astrophysics and Space Research)

In this talk I will describe challenges of simulating thin and super-critical accretion disks and present the numerical methods that allow for global simulations in general relativity. I will then present in detail solutions for disks accreting above the Eddington rate and show that the radiative jets they produce can be very powerful even without any extraction of the black hole rotational energy.


"Changes in CAMK Network"

Krzysztof Leszczyński (NCAC, Warsaw)

From time to time we need to make major changes in our network. This time we need to change the type of authentication. Login and password will no longer be enough to log into our network from the remote sites. Some of services like email will change too. Keywords: eduroam, IPv6, tunnels, VPN, email, ssh.


"Recent results from the hard X-ray - sensitive satellite NuSTAR"

Grzegorz Madejski (Stanford University)