Archivi tag: black holes

Testing Gravity

A three day workshop on various ways of testing gravity (cosmological, astrophysical and terrestrial). This is a topical theme, in part because of the growing interest in modified gravity theories motivated by the unexplained nature of dark matter and dark energy, and in part by improving technologies that open opportunities for new types of tests. Continua a leggere Testing Gravity

The 10° INTEGRAL Workshop “A Synergistic View of the High Energy Sky”

The goal of this workshop is to present and discuss (via invited and contributed talks and posters) the latest results obtained in the field of high-energy astrophysics using the International Gamma-Ray Astrophysics Laboratory INTEGRAL, and place these results in the context of other operational space-based missions, such as Swift, Fermi, AGILE, NuSTAR, and Maxi as well as ground-based VHE observatories. Correlative studies in lower energy bands, as well as neutrino- and gravitational wave observations are included as relevant for various source classes. Continua a leggere The 10° INTEGRAL Workshop “A Synergistic View of the High Energy Sky”

AGN vs star formation: the fate of the gas in galaxies

How is AGN activity connected to star formation? This remains one of the key unsolved questions in astronomy and cosmology. Both processes are efficiently driven by a cold gas supply and we therefore may expect a loose connection. However, a slew of empirical and theoretical evidence suggest an unexpectedly tight symbiotic link between AGN activity and star formation, whereby the fuelling and regulation of one process is dictated by the other. The effectiveness of this fuelling and regulation and (most crucially) whether it is predominantly dictated by AGN activity or star formation is a matter is intense debate, and has important implications for the growth of galaxies and black holes over cosmic time.

The objective of this international workshop is to bring together observers and theorists to discuss the connection between AGN activity and star formation on small (<100 pc), large (~0.1-10 kpc), and cosmological scales to address the following key questions:

  • What evidence is there for a symbiotic connection between AGN activity and star formation?
  • What physical processes drive gas into the centre/how does AGN and star formation compete for cold gas?
  • How does star formation control AGN activity?
  • What impact does AGN activity have on star formation?
  • How different would the Universe look without AGNs?
  • What key tests and observations do we need to make progress in the field?

Poster of the workshop

The X-ray view of galaxy ecosystems

X-ray observations are providing exciting results about the formation and evolution of galaxies, bringing new insight into the interplay between galaxies and the diverse physical components of which they are composed, and with which they interact.  Continua a leggere The X-ray view of galaxy ecosystems

Cosmology and relativistic astrophysics

The 2014 year marks the 100th anniversary of Yakov Zeldovich. The conference will commemorate his contribution to astronomy by concentrating on recent progress in cosmology and high energy astrophysics, the areas where his ideas laid the basis for revolutionary advances. Continua a leggere Cosmology and relativistic astrophysics

Powerful AGN and Their Host Galaxies Across Cosmic Time

2014 will represent 60 years since the optical identification of Cygnus A (Baade & Minkowski, 1954) as an extra-galactic source and the first powerful active galactic nucleus. Since then, powerful AGN have been identified across the electromagnetic spectrum and in galaxies from the local Universe up to z~7. Continua a leggere Powerful AGN and Their Host Galaxies Across Cosmic Time

The physics of first star and galaxy formation

The formation of the first stars, black holes and galaxies is at the frontier of modern astrophysical research. Precision cosmology has revealed that we live in a flat Universe dominated by Dark Energy and Cold Dark Matter. Within this standard paradigm, structure formation proceeds hierarchically forming low mass objects first and subsequently building up larger galaxies all the way up to clusters of galaxies. While the growth of dark matter haloes is driven by gravity and well understood, the baryonic physics governing the formation and growth of stars, black holes and galaxies is more complex and requires the combination of different areas of physics covering such small scales as nuclei all the way up to parsec scale hydrodynamic instabilities.  Continua a leggere The physics of first star and galaxy formation

An hypervelocity star cluster ‘escaping’ from M87

This artist’s illustration shows the hypervelocity star cluster HVGC-1 escaping from the supergiant elliptical galaxy M87. HVGC-1 is the first runaway star cluster discovered by astronomers. It is fated to drift through intergalactic space. David A. Aguilar (CfA)

The galaxy known as M87 has a fastball that would be the envy of any baseball pitcher. It has thrown an entire star cluster toward us at more than two million miles per hour. The newly discovered cluster, which astronomers named HVGC-1, is now on a fast journey to nowhere. Its fate: to drift through the void between the galaxies for all time.

More at CfA: Entire Star Cluster Thrown Out of its Galaxy

arXiv: A Globular Cluster Toward M87 with a Radial Velocity < -1000 km/s: The First Hypervelocity Cluster

The Strong Gravity Regime of Black Holes and Neutron Stars

The 558th WE-Heraeus-Seminar on The Strong Gravity Regime of Black holes and Neutron stars is kindly funded by the Wilhelm und Else Heraeus Foundation. It will be held from March 31st to April 4th, 2014 at the Physikzentrum of the German Physical Society in Bad Honnef near Bonn and Cologne, Germany.

The main theme of this seminar is the observation and theoretical description of systems where gravity is strong and non-linear, in particular systems containing black holes and neutron stars which are ideal gravitational laboratories. To cover the complete complexity of this field of research, experts and graduate students from the observational and theoretical community are invited to bring together their expertise.

As a rough guideline, we have the following categories:

  • Strong-field gravity in GR and its alternatives
  • Black holes as strong field probes
  • Neutron stars as strong field probes
  • Gravitational wave observations and merger events

More info: The Strong Gravity Regime of Black Holes and Neutron Stars