Spiral Galaxies: Evolution and Consequences

    General
    Description

    Our small group is well known and respected internationally for our innovative and important work on various aspects of the structure and evolution of nearby spiral galaxies. We primarily use observations at various wavelengths, exploiting synergies that allow us to answer the most pertinent questions relating to what the main properties of galaxies are, and how galaxies have evolved to their current state. We use imaging and spectroscopy, at UV, optical, infrared, millimetre, and radio wavelengths, fully exploiting observing facilities available to us in Spain, at ESO, or elsewhere, along with state-of-the-art analysis tools. The success of this approach can be measured from the employment opportunities offered to ex-members of the group, from the number and quality of collaborations with leading external scientists, from continued citation of our published work, and from invitations to co-organise or speak at the leading international conferences in the field.

    In the last few years our group has put a lot of effort into opening up joint research lines with computer scientists, recognising the paradigm shift that is upon us due to the enormous quantities of data that will soon be produced by facilities such as LSST, Euclid, and SKA. We collaborate with computer scientists and aim to prepare the analysis tools, including detection of structure from noise, correction for scattered light and Galactic cirrus, and the use of machine learning-based techniques, so that once LSST (2020) and Euclid (2023) start releasing their huge data sets, our group is ready to analyse them and extract the science from the oceans of bytes.

    Principal investigator
    Project staff
    1. From thermal and non-thermal radio maps of the centre of NGC 1097, we discovered that the massive star formation is quenched by non-thermal effects, including pressure from the magnetic field, cosmic rays and turbulence.
    2. In the centre of NGC 7742, we found a slightly warped inner disk, and two separate stellar components: an old population that counter-rotates with the gas, and a young one, concentrated to the ring, that co-rotates with the gas.
    3. We re-analysed our deep IR imaging of thick disks to correct for the extended S4G point spread function (PSF), confirming all our previous results and in particular confirming the significant mass present in the thick disk component.
    4. Analysing a new high-resolution e-MERLIN 1.5 GHz radio continuum map together with HST and SDSS imaging of NGC 5322, an elliptical galaxy hosting radio jets, we found that the low-luminosity AGN/jet-driven feedback may have quenched the late-time nuclear star formation promptly.
    5. From MUSE observations of low-surface-brightness Lyman-α emission surrounding faint galaxies at redshifts between 3 and 6 we find that the projected sky coverage approaches 100 per cent.

    Related publications

    • WEAVE First Light Observations: Origin and Dynamics of the Shock Front in Stephan's Quintet
      We present a detailed study of the large-scale shock front in Stephan's Quintet, a by-product of past and ongoing interactions. Using integral-field spectroscopy from the new William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE), recent 144 MHz observations from the LOFAR Two-metre Sky Survey, and archival data from the Very Large
      Arnaudova, M. I. et al.

      Advertised on:

      12
      2024
      Citations
      0
    • Gas flows in the central region of the Seyfert galaxy NGC 4593 with MUSE
      Context. Understanding how gas flows into galactic centres, fuels the active galactic nucleus (AGN), and is in turn expelled back through feedback processes is of great importance to appreciate the role AGN play in the growth and evolution of galaxies. Aims. We use Multi Unit Spectroscopic Explorer-adaptive optics (MUSE-AO) optical spectra of the
      Baki, P. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • Retrieval of the physical parameters of galaxies from WEAVE-StePS-like data using machine learning
      Context. The William Herschel Telescope Enhanced Area Velocity Explorer (WEAVE) is a new, massively multiplexing spectrograph that allows us to collect about one thousand spectra over a 3 square degree field in one observation. The WEAVE Stellar Population Survey (WEAVE-StePS) in the next 5 years will exploit this new instrument to obtain high-S/N
      Angthopo, J. et al.

      Advertised on:

      10
      2024
      Citations
      0
    • Euclid preparation: XLIII. Measuring detailed galaxy morphologies for Euclid with machine learning
      The Euclid mission is expected to image millions of galaxies at high resolution, providing an extensive dataset with which to study galaxy evolution. Because galaxy morphology is both a fundamental parameter and one that is hard to determine for large samples, we investigate the application of deep learning in predicting the detailed morphologies
      Euclid Collaboration et al.

      Advertised on:

      9
      2024
      Citations
      6
    • Gas-phase metallicity for the Seyfert galaxy NGC 7130
      Metallicity measurements in galaxies can provide valuable clues about galaxy evolution. One of the mechanisms postulated for metallicity redistribution in galaxies is gas flows induced by active galactic nuclei (AGNs), but the details of this process remain elusive. We report the discovery of a positive radial gradient in the gas-phase metallicity
      Amiri, A. et al.

      Advertised on:

      9
      2024
      Citations
      2
    • Deriving the star formation histories of galaxies from spectra with simulation-based inference
      High-resolution galaxy spectra encode information about the stellar populations within galaxies. The properties of the stars, such as their ages, masses, and metallicities, provide insights into the underlying physical processes that drive the growth and transformation of galaxies over cosmic time. We explore a simulation-based inference (SBI)
      Iglesias-Navarro, Patricia et al.

      Advertised on:

      9
      2024
      Citations
      4
    • LeMMINGs. Multiwavelength constraints on the co-existence of nuclear star clusters and AGN in nucleated galaxies
      The relation between nuclear star clusters (NSCs) and the growth of the central supermassive black holes (SMBHs), as well as their connection to the properties of the host galaxies, is crucial for understanding the evolution of galaxies. Recent observations have revealed that about 10 per cent of nucleated galaxies host hybrid nuclei, consisting of
      Dullo, B. T. et al.

      Advertised on:

      8
      2024
      Citations
      0
    • The wide-field, multiplexed, spectroscopic facility WEAVE: Survey design, overview, and simulated implementation
      WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for the William Herschel Telescope, saw first light in late 2022. WEAVE comprises a new 2-deg field-of-view prime-focus corrector system, a nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and a single large IFU
      Jin, Shoko et al.

      Advertised on:

      5
      2024
      Citations
      116
    • Bar properties as a function of wavelength: a local baseline with S<SUP>4</SUP>G for high-redshift studies
      The redshift evolution of bars is an important signpost of the dynamic maturity of disc galaxies. To characterize the intrinsic evolution safe from band-shifting effects, it is necessary to gauge how bar properties vary locally as a function of wavelength. We investigate bar properties in 16 nearby galaxies from the Spitzer Survey of Stellar
      Menéndez-Delmestre, Karín et al.

      Advertised on:

      2
      2024
      Citations
      2
    • Detection of an intranight optical hard lag with colour variability in blazar PKS 0735+178
      Blazars are a highly variable subclass of active galactic nuclei that have been observed to vary significantly during a single night. This intranight variability remains a debated phenomenon, with various mechanisms proposed to explain the behaviour including jet energy density evolution or system geometric changes. We present the results of an
      McCall, Callum et al.

      Advertised on:

      3
      2024
      Citations
      1
    • Strategies for optimal sky subtraction in the low surface brightness regime
      The low surface brightness (LSB) regime (μ g ≳ 26 mag arcsec -2) comprises a vast, mostly unexplored discovery space, from dwarf galaxies to the diffuse interstellar medium. Accessing this regime requires precisely removing instrumental signatures and light contamination, including, most critically, night sky emission. This is not trivial, as faint
      Watkins, Aaron E. et al.

      Advertised on:

      3
      2024
      Citations
      7
    • Preparing for low surface brightness science with the Vera C. Rubin Observatory: a comparison of observable and simulated intracluster light fractions
      Intracluster light (ICL) provides an important record of the interactions galaxy clusters have undergone. However, we are limited in our understanding by our measurement methods. To address this, we measure the fraction of cluster light that is held in the Brightest Cluster Galaxy and ICL (BCG+ICL fraction) and the ICL alone (ICL fraction) using
      Brough, Sarah et al.

      Advertised on:

      2
      2024
      Citations
      13
    • Constraining the top-light initial mass function in the extended ultraviolet disk of M 83
      Context. The universality or non-universality of the initial mass function (IMF) has significant implications for determining star formation rates and star formation histories from photometric properties of stellar populations. Aims: We reexamine whether the IMF is deficient in high-mass stars (top-light) in the low-density environment of the outer
      Rautio, R. P. V. et al.

      Advertised on:

      1
      2024
      Citations
      4
    • On the Nature of Disks at High Redshift Seen by JWST/CEERS with Contrastive Learning and Cosmological Simulations
      Visual inspections of the first optical rest-frame images from JWST have indicated a surprisingly high fraction of disk galaxies at high redshifts. Here, we alternatively apply self-supervised machine learning to explore the morphological diversity at z ≥ 3. Our proposed data-driven representation scheme of galaxy morphologies, calibrated on mock
      Vega-Ferrero, Jesús et al.

      Advertised on:

      1
      2024
      Citations
      31
    • A giant thin stellar stream in the Coma Galaxy Cluster
      The study of dynamically cold stellar streams reveals information about the gravitational potential where they reside and provides important constraints on the properties of dark matter. However, the intrinsic faintness of these streams makes their detection beyond Local environments highly challenging. Here, we report the detection of an extremely
      Sánchez-Alarcón, Pablo M. et al.

      Advertised on:

      11
      2023
      Citations
      9
    • Composite Bulges. III. A Study of Nuclear Star Clusters in Nearby Spiral Galaxies
      We present photometric and morphological analyses of nuclear star clusters (NSCs)-very dense, massive star clusters present in the central regions of most galaxies-in a sample of 33 massive disk galaxies within 20 Mpc, part of the "Composite Bulges Survey." We use data from the Hubble Space Telescope including optical (F475W and F814W) and near-IR
      Ashok, Aishwarya et al.

      Advertised on:

      11
      2023
      Citations
      5
    • The truncation of the disk of NGC 4565. Detected up to z = 4 kpc, with star formation, and affected by the warp
      Context. The hierarchical model of galaxy formation suggests that galaxies are continuously growing. However, our position inside the Milky Way prevents us from studying the disk edge. Truncations are low surface brightness features located in the disk outskirts of external galaxies. They indicate where the disk brightness abruptly drops, and their
      Martínez-Lombilla, Cristina et al.

      Advertised on:

      10
      2023
      Citations
      4
    • Stellar metallicity from optical and UV spectral indices: Test case for WEAVE-StePS
      Context. The upcoming generation of optical spectrographs on four meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide high-quality spectra for thousands of galaxies. These data will allow us to examine of the stellar population properties at
      Ditrani, F. R. et al.

      Advertised on:

      9
      2023
      Citations
      3
    • The AMIGA sample of isolated galaxies. XIV. Disc breaks and interactions through ultra-deep optical imaging
      Context. In the standard cosmological model of galaxy evolution, mergers and interactions play a fundamental role in shaping galaxies. Galaxies that are currently isolated are thus interesting because they allow us to distinguish between internal and external processes that affect the galactic structure. However, current observational limits may
      Sánchez-Alarcón, P. M. et al.

      Advertised on:

      9
      2023
      Citations
      8
    • A brief review of contrastive learning applied to astrophysics
      Reliable tools to extract patterns from high-dimensionality spaces are becoming more necessary as astronomical data sets increase both in volume and complexity. Contrastive Learning is a self-supervised machine learning algorithm that extracts informative measurements from multidimensional data sets, which has become increasingly popular in the
      Huertas-Company, Marc et al.

      Advertised on:

      1
      2023
      Citations
      14

    Related talks

    No related talks were found.

    Related conferences

    No related conferences were found.