Ministerio de Economía y Competitividad Gobierno de Canarias Universidad de La Laguna CSIC Centro de Excelencia Severo Ochoa

Astrophysics Research Projects

The Local Universe

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Barred Galaxies: Evolution and Consequences (P/300724)

J H KNAPEN

Fatemeh Tabatabaei, Cristina Martínez Lombilla, PD BIG DATA, Simón Díaz García, Roshan Nushkia Chamba, FPI AYA2016-76219-P

 R. Buta (Univ. Alabama); E. Laurikainen, H. Salo, S. Comeron, J. Laine (Univ. Oulu); E. Brinks, M. Sarzi (Univ. Hertfordshire, RU); P. James, C. Collins, I. Steele, S. Longmore, S. Wich, L. Kelvin (Liverpool John Moores Univ., R.U.); M. Querejeta (ESO, Alemania); R. Peletier, S. Trager, M. Wilkinson (Groningen, Paises Bajos); B. Elmegreen (IBM, EEUU); D. Elmegreen (Vassar, EEUU); R. Beswick (Manchester, R.U.); I. McHardy (Southampton); B. Madore, M. Seidel (Carnegie); S. Erroz (ETH Zurich); J. Lee (STScI), J. Braine (Bordeaux), C. Kramer (IRAM), S. A. Mao (MPIfR), E. Schinnerer, R. Leaman (MPIA), R. J. Kennicutt (IOA, Cambridge) & The KINGFISH collaboration, J. van Loon (Keele University), C. Horrellou (Onsala Space Observatory) & The MKSP collaboration, A. Scaife (Manchester University), B. Dullo (UCM), T. Martinsson (CSIC), V. Debattista (University of Central Lancashire)

Introduction

Most galaxies in the local Universe are barred and from images taken with the Hubble Space Telescope we know that the barred galaxy fraction has been constant for the last 8 billion years (z~1). Given that bars are signposts of deviations from an axisymmetric gravitational potential, they have important consequences for the dynamics and evolution of their host galaxies. In this Project we study the structure and evolution of galactic bars, and the consequences of their existence for topics such as the distribution and properties of the interstellar medium, the star formation, and the structure of their host galaxies. In the first place, we will investigate the properties of bars and disks by analyzing samples of galaxies as observed with a variety of modern telescopes. We will use near-infrared, optical and radio, obtained with Spitzer and with ground-based telescopes, to study local galaxies, and imaging from the Hubble to study galaxies at higher redshifts. Secondly, we will study some of the consequences of bars, and in particular how bars relate to the secular evolution of galaxies. This includes the detailed study of rings in galaxies, and of bars in lenticular as compared to spiral galaxies. Thirdly, we study the structure, kinematics and evolution of galaxy discs using images and spectroscopy of nearby galaxies and galaxies at redshifts of up to 1.

Milestones

- Discovered the role of the non-thermal ISM in quenching massive star formation and submitted paper to Nature Astronomy where it was accepted for publication.

- Studied the spectral energy distribution (SED) of the radio continuum (RC) emission from the KINGFISHER sample of nearby galaxies to understand the energetics and origin of this emission. Comparing the radio and IR SEDs, found that the FIR-to-MRC ratio could decrease with SFR, due to the amplification of the magnetic fields in star-forming regions. This particularly implies a decrease in the ratio at high redshifts, where mostly luminous/star-forming galaxies are detected.

- Analysed the position of the truncation in the 2 edge-on spiral galaxies NGC 4565 and NGC 5907 (from NUV to NIR) and its dependence with height and wavelenght. No dependence was found. We found the characteristic U-shaped radial colour profile associated with a star formation threshold at the location of the truncation. We calculated a disk growth rate of less than 0.6-0.9 kpc Gyr−1, assuming that galaxy discs grow inside-out.

- Started the EU-funded Innovative Training Network SUNDIAL and recruited a PhD student to work in that project

- Edited two books that were published in 2017: an IAU Symposium Proceedings volume (published by Cambridge) and a volume containing 10 invited reviews on Outskirts of Galaxies, published by Springer. Co-authored one of the ten invited reviews with Ignacio Trujillo.

- We presented high-sensitivity eMERLIN radio images of the Seyfert galaxy NGC 4151 at 1.51 GHz, and compared the new eMERLIN images to those from archival MERLIN observations in 1993 to determine the change in jet morphology in the 22 yr between observations. We report an increase by almost a factor of 2 in the peak flux density of the central core component, C4, thought to host the black hole, but a probable decrease in some other components, possibly due to adiabatic expansion. Photoionization from the central AGN, with additional ionization by the jet, is responsible for the observed emission-line properties in the central region.

- Using data from the IAC Stripe82 Legacy Project to study the surface photometry of 22 nearby, face-on to moderately inclined spiral galaxies, we find truncations in three galaxies and evidence for haloes in many more. The presence of these haloes and of truncations is mutually exclusive, and we argue that the presence of a stellar halo and/or light scattered by the PSF can hide truncations.

- We described an unmanned aerial system equipped with a thermal-infrared camera and software pipeline that we have developed to monitor animal populations for conservation purposes. We demonstrate that the pipeline works reliably and describe how it can be used to estimate the completeness of different observational datasets to objects of a given type as a function of height, observing conditions etc. - a crucial step in converting video footage to scientifically useful information such as the spatial distribution and density of different animal species.

 

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