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General
The basic objective of the broject is to investigate the evolution of galaxies by deepening our understanding of the interaction between the insterstellar medium and the stars.The main technique which we use is the two-dimensional kinematic study of whole galaxies observed using our instrument:GHaFaS, a Fabry-Perot interferometer on the William Herschel Telescope of the ORM.
We combine the data from GHaFaS with our own photometric imaging using ACAM on the same telescope, with a variety of sources of images in the infrared and ultraviolet, and with emission line maps en the radio and milimetre range to explore the effects, and the physical parameters which the determine the star formation rate and the mass function of the stars depending on the sites of their formation in galaxies.
In the present phase of the project the dynamical aspects which we are e xploring are basically two: the resonant structure of discs and bars, and the effects of the zones of massive star formation on their surroundings via stellar winds and supernovae.In addition, in preparation for the exploration of galaxy formation in earlier epochs, we are studying how the interactions between galaxies stimulate and condition star formation within them before they merge. In the future these studies will be extended, methodically, in two directions: outwards to galaxies at increasing redshift, and inwards by applying our methods to the study of interstellar porcesse in the zones of massive star formation in the Local Group galaxy M33.
We combine our research into galaxy kinematics with evolutionary aspects of galaxy discs based on precise observations of their surface brightness profiles, both in local galaxies and in galaxies at intermediate redshift. In order to make progress in this direction we are collaborating with colleagues at the Instituto de Astronomía de la UNAM (México) and the Laboratoire d'Astrophysique de Marseille (France) in the implementation of a new instrument, NEFER, which will be a high resolution Fabry-Perot module incorporated into OSIRIS on the GTC. We had successful inicial trials in December 2017, and commissioneed NEFER in March 2018 for use as a visitor instrument permanently on the GTC.
Members
Results
- The "Font-Beckman" method for analysing resonances in galaxies was shown to give very accurate results, comparing it with the "Tremaine-Weinberg" method using data from GHaFaS (WHT and MUSE (VLT)
- The profiles of Type III (antitruncated) S0 galaxies were measured at z = 0.6 (5 thousan dmillion years ago) for the first time. The "break radius" is the same as that of local galaxies, but its surface brightness is 1.6 magnitudes brighter.
- A new and greatly improved analysis of the Hubble Ultra-Deep Field gave an image with valid photometry down to 33 mag /arcsec squared, revealing the faint outskirts of it galaxies,.
- Comparing galaxies in interacting pairs with isolated galaxies it was shown that the star formation rate in the former is consistently enhanced and that this enhancement is common to the discs and the tidal tails
- The galaxy NGC 864 (CIG 86), apparently isolated, shows an asymmetric distribution of its hI. It was shown that this galaxy is truly isolated, and that HI accretion probably accounts for the asymmetry as well as the star formation in its stellar pseud-ring
Scientific activity
Related publications
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GHαFaS: Galaxy Hα Fabry-Perot System for the William Herschel TelescopeGHαFaS, a new Fabry-Perot system, is now available at the William Herschel Telescope (WHT). It was mounted, for the first time, at the Nasmyth focus of the 4.2-m WHT on La Palma in 2007 July. Using modern technology, with a spectral resolution of the order R˜15,000, and with a seeing-limited spatial resolution, GHαFaS will provide a new look at theHernandez, O. et al.
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62008 -
Explaining the Galactic Interstellar Dust Grain Size Distribution FunctionWe present here a new theoretical model designed to explain the interstellar dust grain size distribution function (IDGSDF), and compare its results with previous observationally derived distributions and with previous theoretical models. The range of grain sizes produced in the late stages of stars with different masses is considered, and foldedCasuso, E. et al.
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42010 -
Discovery of ultra-compact nuclear rings in three spiral galaxiesRing-shaped morphologies of nuclear star-forming regions within the central 40{-}200 pc of disk galaxies have been barely resolved so far in three composite Sy 2 nuclei, the Sy 2 Circinus galaxy and in three non-AGN galaxies. Such morphologies resemble those of the standard 1 kpc-size nuclear rings that lie in the inner Lindblad resonance regionsComerón, S. et al.
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22008 -
Cosmic Evolution of Stellar Disk Truncations: From z~1 to the Local UniverseWe have conducted the largest systematic search so far for stellar disk truncations in disklike galaxies at intermediate redshift (zAzzollini, R. et al.
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92008 -
Color Profiles of Disk Galaxies since z ~ 1: Probing Outer Disk Formation ScenariosWe present deep color profiles for a sample of 415 disk galaxies within the redshift range 0.1Azzollini, R. et al.
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62008 -
An improved method for statistical studies of the internal kinematics of HII regions: the case of M83We present the integrated Hα emission line profile for 157 HII regions in the central 3.4 × 3.4 arcmin2 of the galaxy M83 (NGC 5236). Using the Fabry-Perot interferometer GHαFAS, on the 4.2-m William Herschel Telescope on La Palma, we show the importance of a good characterization of the instrumental response function for the study of line profileBlasco-Herrera, J. et al.
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102010 -
AINUR: Atlas of Images of NUclear RingsWe present the most complete atlas of nuclear rings to date. We include 113 rings found in 107 galaxies, six of which are elliptical galaxies, five are highly inclined disc galaxies, 18 are unbarred disc galaxies and 78 are barred disc galaxies. Star-forming nuclear rings occur in 20 +/- 2 per cent of disc galaxies with types between T = -3 and T =Comerón, S. et al.
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32010 -
A Strong Dichotomy in S0 Disk Profiles between the Virgo Cluster and the FieldWe report evidence for a striking difference between S0 galaxies in the local field and the Virgo Cluster. While field S0 galaxies have disks whose surface-brightness profiles are roughly equally divided between the three main types (Types I, II, and III: single-exponential, truncated, and antitruncated), Virgo S0s appear to be entirely lacking inErwin, Peter et al.
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