Place: Villafranca del Castillo, near Madrid, Spain
Gigantic X-ray, UV and optical flares have been seen from the nuclei of a
small number of galaxies. These extraordinary flares have been interpreted as
the tidal disruption of a stellar object by a quiescent black hole, if the
hosts were non-active, or as dramatic changes in the accretion environment, if
the galaxy appeared as a classical AGN. The very distinctive lightcurves and
spectra of tidal disruption events (TDE), predicted in advance by pioneering
theoretical work, clearly distinguish them from AGN activity and establish them
as an important field of study in their own right. Recent, high-quality
observations of TDE, differ in detail from early expectations of thermal
emission from steadily returning stellar debris and challenge the sophisticated
theoretical and numerical models which are now emerging. Large, and very rare,
flux changes in known AGN, pose challenges for our understanding of accretion
disk processes and the immediate nuclear environment. The discovery of jetted
emission from SWIFT J1644+57, probably induced by a stellar disruption, has
opened a new window into the phenomenon and provides a further link between
tidal disruption events and AGN.
Over the next few years, sensitive, large-area, surveys will come on-line and
likely detect extragalactic flares in large numbers. This workshop is designed
to bring together theorists and observers for a review of previous observations
and state-of-the-art modelling, and help to develop a strategy for the
identification and follow-up of future events. The workshop aims to address
the following topics:
Observations: What giant flares have been seen to date in the X-ray, UV
and optical?
Numbers: What are the stellar dynamics in galaxy cores, what is the rate
of flares and are they important for the universal fueling of (super)massive
black holes?
New missions/surveys: What is coming; how many objects will they find,
what will they be able to measure, and to what accuracy - eRosita, PanStarrs,
LSST, LAMOST, LOFAR....
Theoretical explanations: Tidal disruptions, AGN disks, jets - what do
they predict and what needs to be observed to test the models?
Tidal disruption models: How do tidal disruption, tidal detonation and
tidal stripping work? How much gas is accreted, how much expelled? Do strong
disk winds develop, and when?
Jets and radio emission: When and how are jets formed during a
disruption? What is their evolution?
Emission line light echoes from a nuclear flare: What can they tell us
about the circumnuclear material?
AGN outbursts: What are the mechanisms and are some of them related to
tidal disruptions?
Interaction of stellar or compact objects with an accretion disk: How to
search for periodic flare patterns and characteristic thermal bremsstrahlung
spectra?
What are the sources of false alarms: Changes in line-of-sight
obscuration to AGN, SNe, ULX, BLAZARS, GRBs and how can we discriminate
against them (or are they physically related)?
Gravitational waves: What can be detected from stellar inspirals,
partial disruption of compact stars and binary black hole mergers?
Applications: How can we use tidal flares to detect massive binary black
holes and recoiling black holes ? What do they tell us about stellar dynamics
in galactic nuclei? What else can we use them for?
How to plan a follow-up campaign: What needs to be observed and when?
Contact e-mails are tdconf_esac2012 at sciops.esa.int, richard.saxton at
sciops.esa.int and carlos.gabriel at sciops.esa.int.
