3 results
6 - Extragalactic studies and future integral field spectroscopy science
-
- By Luis Colina
- Edited by Evencio Mediavilla, Instituto de Astrofísica de Canarias, Tenerife, Santiago Arribas, Space Telescope Science Institute, Baltimore, Martin Roth, Jordi Cepa-Nogué, Instituto de Astrofísica de Canarias, Tenerife, Francisco Sánchez
-
- Book:
- 3D Spectroscopy in Astronomy
- Published online:
- 06 August 2010
- Print publication:
- 28 January 2010, pp 200-224
-
- Chapter
- Export citation
-
Summary
In this set of lectures, I review recent observational progress on extragalactic studies using integral field spectroscopy (IFS) techniques, highlighting the importance of IFS for the study of the nuclear regions of nearby galaxies, of low-z active galactic nuclei (AGN) and massive star-forming galaxies, and of high-z galaxies, including lensed quasars, lensing galaxies and bright submillimetre galaxies. Emphasis is given to the study of (ultra)luminous infrared galaxies as examples of low-z systems where the physical processes relevant to the formation and evolution of galaxies can be investigated in more detail. Research projects involving future ground-based facilities and satellites are also briefly presented.
Introduction
The use of IFS for extragalactic studies has burgeoned over the past 10 years and is already becoming a standard observational technique used by several groups in many different areas. Most IFS systems (INTEGRAL, GMOS, PMAS, SAURON, SINFONI, VIMOS, etc.) allow us to simultaneously obtain spectra covering a wide spectral range over a wide field of view (up to 1 arcmin square for VIMOS). These instruments in their standard configurations provide low–intermediate spectral resolution (R of 1000 to 4000) with a relatively low angular resolution (0.5″ to 3.0″). In addition, a few IFS systems, such as OASIS on the William Herschel Telescope and SINFONI on the Very Large Telescope (VLT), can provide very high angular resolution (i.e. 0.1″) in the optical (OASIS) and near-infrared (SINFONI) when combined with adaptive optics (AO) systems.
Multi-Wavelength Observations of “Interactive” Galaxies (Poster paper)
- Edited by Isaac Shlosman, University of Kentucky
-
- Book:
- Mass-Transfer Induced Activity in Galaxies
- Published online:
- 05 May 2010
- Print publication:
- 02 June 1994, pp 384-385
-
- Chapter
- Export citation
-
Summary
ABSTRACT
We are studying the optical, radio, and X-ray morphologies of interacting galaxies in which at least one member is also an active galaxy. Deformed gas distributions are seen in galaxies that also show optical evidence of tidal deformation, indicating significant gas redistribution in these interacting systems, thereby providing compelling evidence for a causal connection between tidal and nuclear activity in “interactive” galaxies.
THE INTERACTION-ACTIVITY CONNECTION
Stockton (1990) and Heckman (1990) have reviewed the wealth of evidence indicating that galaxy interactions are somehow related to the generation of starburst and AGN activity in galactic nuclei. For example, a large fraction of low-luminosity radio and active galaxies have nearby companions or show evidence for a recent gravitational encounter (e.g., MacKenty 1989). In an optical study of galaxies selected on the basis that they all contain well defined radio jets, it was found that almost half of the sample consists of pairs of elliptical galaxies (Colina and Pérez-Fournon 1990a, b). Many of these low-luminosity radio galaxies with companions (e.g., 3C31, 3C278, and 3C449) show a well defined distorted radio jet structure at the VLA scale with an S– or C-shaped morphology. We are currently studying these systems across many wavebands (optical, radio, and X-ray) in an attempt to model the observed morphologies in each case and thereby constrain the various properties of the system (orbital parameters, jet parameters, and hot gas distribution, respectively). These system constraints will hopefully offer some physical insight into the interaction-activity connection.
Radio Emission and the Nature of Compact Objects in AGN
- from I - Evidence and Implications of Anisotropy in AGN
-
- By Luis Colina, Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
- Edited by Andrew Robinson, University of Cambridge, Roberto Juan Terlevich, Royal Greenwich Observatory, Cambridge
-
- Book:
- The Nature of Compact Objects in Active Galactic Nuclei
- Published online:
- 04 August 2010
- Print publication:
- 03 March 1994, pp 78-81
-
- Chapter
- Export citation
-
Summary
Abstract
The radio properties of radio quiet active galaxies are revisited and considered under the starburst without black hole model. These radio properties are consistent with the luminosity, compactness and spectral index expected from a massive starburst process, where bright and compact radio supernovae and supernova remnants, i.e. radio hypernovœ, generate the radio emission.
Introduction
Since the discovery of quasars, theoretical and observational work has been done in order to characterize the variety of active galactic nuclei (AGNs), and to understand the physical mechanisms operating in these regions. The most popular scenario considers the presence of an accretion disc around a massive black hole. Under this scenario, different regimes of accretion and/or black hole masses plus some anisotropy in the radiation field could account for the whole variety of AGNs. Alternatively, a different model based on the evolution of a central compact star cluster, has been proposed and worked out in some detail (Terlevich, 1990 and references).
A natural way to ascertain the true nature of the compact objects in AGNs, is to look at the central regions of galaxies with the highest spatial resolution available, i.e. radio observations. High resolution VLBI and VLA observations with 5 and 250 mas resolution, respectively, allow the nuclei and cores of nearby active galaxies to be mapped with typical resolutions of a few parsecs. In this paper I briefly discuss the radio properties, absolute luminosity, spectral index, morphology and compactness of radio quiet active galaxies and compare these properties with the predictions of the starburst model.