12 research outputs found
Sky Surveys
Sky surveys represent a fundamental data basis for astronomy. We use them to
map in a systematic way the universe and its constituents, and to discover new
types of objects or phenomena. We review the subject, with an emphasis on the
wide-field imaging surveys, placing them in a broader scientific and historical
context. Surveys are the largest data generators in astronomy, propelled by the
advances in information and computation technology, and have transformed the
ways in which astronomy is done. We describe the variety and the general
properties of surveys, the ways in which they may be quantified and compared,
and offer some figures of merit that can be used to compare their scientific
discovery potential. Surveys enable a very wide range of science; that is
perhaps their key unifying characteristic. As new domains of the observable
parameter space open up thanks to the advances in technology, surveys are often
the initial step in their exploration. Science can be done with the survey data
alone or a combination of different surveys, or with a targeted follow-up of
potentially interesting selected sources. Surveys can be used to generate
large, statistical samples of objects that can be studied as populations, or as
tracers of larger structures. They can be also used to discover or generate
samples of rare or unusual objects, and may lead to discoveries of some
previously unknown types. We discuss a general framework of parameter spaces
that can be used for an assessment and comparison of different surveys, and the
strategies for their scientific exploration. As we move into the Petascale
regime, an effective processing and scientific exploitation of such large data
sets and data streams poses many challenges, some of which may be addressed in
the framework of Virtual Observatory and Astroinformatics, with a broader
application of data mining and knowledge discovery technologies.Comment: An invited chapter, to appear in Astronomical Techniques, Software,
and Data (ed. H. Bond), Vol.2 of Planets, Stars, and Stellar Systems (ser.
ed. T. Oswalt), Springer Verlag, in press (2012). 62 pages, incl. 2 tables
and 3 figure
Black holes, gravitational waves and fundamental physics: a roadmap
The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions.
The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature.
The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'
Probing the dark universe with gravitational lensing
Since its early success as an experimental test of the theory of general relativity in 1919,
gravitational lensing has come a long way and is firmly established as an indispensable element
for many astrophysical applications. In this thesis, we explore novel applications of gravitational
lensing that further our understanding of the dark sectors of the cosmos and other astrophysical
objects, namely dark matter nanostructure, black holes and the Galactic disk. We pay particular
attention to developing concrete and optimal statistical methodologies and numerical implemen-
tations for these novel probes.
We start by developing a statistical framework to measure the dark matter power spectrum in
the deep nonlinear regime, using transient weak lensing, and simultaneously measure the time
delays for strongly lensed quasars. We then outline how observations of microlensing in optical
and radio can unravel the structure, dynamics, and content of the Galactic disk, and in particular,
be used to detect stellar mass black holes. Lastly, using the shadow images of the super-massive
black holes caused by extreme lensing effect, we can learn about the structure of space-time,
accretion flows and astrophysical jets. We present a Bayesian framework for analyzing the data
from the Event Horizon Telescope Collaboration
Black holes, gravitational waves and fundamental physics: a roadmap
The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'
Black holes, gravitational waves and fundamental physics: a roadmap
The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions.
The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature.
The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'