TITAN is a computer program for calculating the interactions of a dilute plane-parallel medium with electromagnetic radiation. It includes all atomic processes: absorption, recombination, diffusion, excitation, deexcitation of atoms and ions, heating and cooling of the gas, and it solves the radiation transfer, in order to obtain the spectra reemitted by the medium. It handles plan parallel slabs in non LTE steady state, for various physical conditions and various illuminations, valid in many astrophysical situations. It is specifically designed for warm-hot (8000 to 10**8 K) and thick media (till an electron scattering optical depth of several tens) emitting and absorbing in the X-ray range (density from 10**5 to 10**14 cm-3). It computes the physical parameters, ionisation degrees, temperature, density, and the spectrum of the radiated light in each point of the slab, by solving simultaneously the ionisation equations, the equations of statistical equilibrium, the thermal equations and the radiation transfer, using iteration processes.
The Multi-Order Coverage map method (MOC) is dedicated to specify arbitrary sky regions.
The goal is to be able to provide a very fast comparison mechanism between coverage maps.
The mechanism is based on the HEALPix sky tessellation algorithm.
It is essentially a simple way to map regions of the sky into hierarchically
grouped predefined cells.
A service in the Common Execution Architecture. This service provides one or more science applications which are separately registered. See the ManagedApplications element of this document for a list of applications.
This resource describes the community webapplication at MSSL. It hosts all the accounts and secure accounts of people organized at MSSL. And possibly other outside people of MSSL but associated with projects of MSSL.
Observation Data Model Core Components
and its Implementation in the Table Access Protocol
Date:
10 May 2017 08:00:00
Publisher:
IVOA
Description:
This document defines the core components of the Observation data model
that are necessary to perform data discovery when querying data centers
for astronomical observations of interest. It exposes use-cases to be carried out,
explains the model and provides guidelines for its implementation as a data access
service based on the Table Access Protocol (TAP).
It aims at providing a simple model easy to understand and to implement by data
providers that wish to publish their data into the Virtual Observatory. This
interface integrates data modeling and data access aspects in a single service and
is named ObsTAP. It will be referenced as such in the IVOA registries.
In this document, the Observation Data Model Core Components (ObsCoreDM) defines
the core components of queryable metadata required for global discovery of
observational data. It is meant to allow a single query to be posed to TAP
services at multiple sites to perform global data discovery without having to
understand the details of the services present at each site. It defines a minimal
set of basic metadata and thus allows for a reasonable cost of implementation by
data providers. As with most of the VO Data Models, ObsCoreDM makes use of STC,
Utypes, Units and UCDs. The ObsCoreDM can be serialized as a VOTable. ObsCoreDM
can make reference to more complete data models such as Characterisation DM,
Spectrum DM or Simple Spectral Line Data Model (SSLDM). ObsCore shares a large set
of common concepts with DataSet Metadata Data Model (Cresitello-Dittmar et al. 2016)
which binds together most of the data model concepts from the above models in a
comprehensive and more general frame work. This current specification on the
contrary provides guidelines for implementing these concepts using the TAP protocol
and answering ADQL queries. It is dedicated to global discovery.