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

    • Euclid preparation. XVI. Exploring the ultra-low surface brightness Universe with Euclid/VIS
      Context. While Euclid is an ESA mission specifically designed to investigate the nature of dark energy and dark matter, the planned unprecedented combination of survey area (∼15 000 deg 2), spatial resolution, low sky-background, and depth also make Euclid an excellent space observatory for the study of the low surface brightness Universe
      Euclid Collaboration et al.

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      1
      2022
      Citations
      31
    • Euclid preparation. XIII. Forecasts for galaxy morphology with the Euclid Survey using deep generative models
      We present a machine learning framework to simulate realistic galaxies for the Euclid Survey, producing more complex and realistic galaxies than the analytical simulations currently used in Euclid. The proposed method combines a control on galaxy shape parameters offered by analytic models with realistic surface brightness distributions learned
      Euclid Collaboration et al.

      Advertised on:

      1
      2022
      Citations
      17
    • A low-cost chopping system and uncooled microbolometer array for ground-based astronomy
      Mid-Infrared imaging is vital for the study of a wide variety of astronomical phenomena, including evolved stars, exoplanets, and dust enshrouded processes such as star formation in galaxies. However, infrared detectors have traditionally been expensive and it is difficult to achieve the sensitivity needed to see beyond the overwhelming mid
      Rashman, M. F. et al.

      Advertised on:

      4
      2021
    • WALLABY pilot survey: H I gas disc truncation and star formation of galaxies falling into the Hydra I cluster
      We present results from our analysis of the Hydra I cluster observed in neutral atomic hydrogen (H I) as part of the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). These WALLABY observations cover a 60-square-degree field of view with uniform sensitivity and a spatial resolution of 30 arcsec. We use these wide-field observations to
      Reynolds, T. N. et al.

      Advertised on:

      2
      2022
      Citations
      16
    • Extragalactic Magnetism with SOFIA (Legacy Program) - II: A Magnetically Driven Flow in the Starburst Ring of NGC 1097
      Galactic bars are frequent in disk galaxies and they may support the transfer of matter toward the central engine of active nuclei. The barred galaxy NGC 1097 has magnetic forces controlling the gas flow at several kpc scales, which suggest that magnetic fields (B-fields) are dynamically important along the bar and nuclear ring. However, the effect
      Lopez-Rodriguez, Enrique et al.

      Advertised on:

      12
      2021
      Citations
      19
    • Discovery and analysis of low-surface-brightness galaxies in the environment of NGC 1052
      The environment of NGC 1052 has recently attracted much attention because of the presence of low-surface-brightness galaxies (LSBGs) with apparently "exotic" properties, making it a region of high interest for the detection of new objects. We used public deep photometric data from the Dark Energy Camera Legacy Survey to carry out a comprehensive
      Román, Javier et al.

      Advertised on:

      12
      2021
      Citations
      24
    • Capturing the Physics of MaNGA Galaxies with Self-supervised Machine Learning
      As available data sets grow in size and complexity, advanced visualization tools enabling their exploration and analysis become more important. In modern astronomy, integral field spectroscopic galaxy surveys are a clear example of increasing high dimensionality and complex data sets, which challenges the traditional methods used to extract the
      Sarmiento, Regina et al.

      Advertised on:

      11
      2021
      Citations
      22
    • Extragalactic Magnetism with SOFIA (Legacy Program). I. The Magnetic Field in the Multiphase Interstellar Medium of M51
      The recent availability of high-resolution far-infrared (FIR) polarization observations of galaxies using HAWC+/SOFIA has facilitated studies of extragalactic magnetic fields in the cold and dense molecular disks. We investigate whether any significant structural differences are detectable in the kiloparsec-scale magnetic field of the grand design
      Borlaff, Alejandro S. et al.

      Advertised on:

      11
      2021
      Citations
      27
    • Fractal dimension of optical cirrus in Stripe82
      The geometric characteristics of dust clouds provide important information on the physical processes that structure such clouds. One of such characteristics is the 2D fractal dimension D of a cloud projected on to the sky plane. In previous studies, which were mostly based on infrared (IR) data, the fractal dimension of individual clouds was found
      Marchuk, Alexander A. et al.

      Advertised on:

      12
      2021
      Citations
      9
    • Molecular gas and star formation within 12 strong galactic bars observed with IRAM-30 m
      Context. While some galactic bars show recent massive star formation (SF) along them, some others do not. Whether bars with low level of SF are a consequence of low star formation efficiency, low gas inflow rate, or dynamical effects remains a matter of debate. Aims: In order to study the physical conditions that enable or prevent SF, we perform a
      Díaz-García, S. et al.

      Advertised on:

      10
      2021
      Citations
      11
    • LeMMINGs III. The e-MERLIN legacy survey of the Palomar sample: exploring the origin of nuclear radio emission in active and inactive galaxies through the [O III] - radio connection
      What determines the nuclear radio emission in local galaxies? To address this question, we combine optical [O III] line emission, robust black hole (BH) mass estimates, and high-resolution e-MERLIN 1.5-GHz data, from the LeMMINGs survey, of a statistically complete sample of 280 nearby optically active (LINER and Seyfert) and inactive [H II and
      Baldi, R. D. et al.

      Advertised on:

      12
      2021
      Citations
      19
    • Introducing the LBT Imaging of Galactic Halos and Tidal Structures (LIGHTS) survey. A preview of the low surface brightness Universe to be unveiled by LSST
      We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2 × 8.4 m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of μ V ∼ 31 mag arcsec −2 (3σ in 10″ × 10″
      Trujillo, Ignacio et al.

      Advertised on:

      10
      2021
      Citations
      34
    • WALLABY pre-pilot survey: two dark clouds in the vicinity of NGC 1395
      We present the Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pre-pilot observations of two 'dark' H I sources (with H I masses of a few times 10 8 $\rm {M}_\odot$ and no known stellar counterpart) that reside within 363 kpc of NGC 1395, the most massive early-type galaxy in the Eridanus group of galaxies. We investigate whether these
      Wong, O. I. et al.

      Advertised on:

      10
      2021
      Citations
      12
    • Tracing satellite planes in the Sculptor group. I. Discovery of three faint dwarf galaxies around NGC 253
      Context. In recent years, a new generation of large-scale imaging surveys have probed wide field regions for the first time around some nearby galaxies in an unprecedentedly low surface-brightness regime (∼28.0−29.0 mag arcsec −2). This provides the chance to discover very faint dwarf satellites by means of systematic visual inspection of these
      Martínez-Delgado, David et al.

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      8
      2021
      Citations
      29
    • A feather on the hat: tracing the giant stellar stream around the Sombrero galaxy
      Recent evidence of extremely metal-rich stars found in the Sombrero galaxy (M104) halo suggests that this galaxy has undergone a recent major merger with a relatively massive galaxy. In this paper, we present wide-field deep images of the M104 outskirts obtained with a 18-cm amateur telescope with the purpose of detecting any coherent tidal
      Martínez-Delgado, David et al.

      Advertised on:

      10
      2021
      Citations
      14
    • The centres of M83 and the Milky Way: opposite extremes of a common star formation cycle
      In the centres of the Milky Way and M83, the global environmental properties thought to control star formation are very similar. However, M83's nuclear star formation rate (SFR), as estimated by synchrotron and H α emission, is an order of magnitude higher than the Milky Way's. To understand the origin of this difference we use ALMA observations of
      Callanan, Daniel et al.

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      8
      2021
      Citations
      19
    • A diffuse tidal dwarf galaxy destined to fade out as a "dark galaxy"
      We have explored the properties of a peculiar object detected in deep optical imaging and located at the tip of an H I tail emerging from Hickson Compact Group 16. Using multiband photometry from infrared to ultraviolet, we were able to constrain its stellar age to 58 ‒9 +22 Myr with a rather high metallicity of [Fe/H] = ‒0.16 ‒0.41 +0.43 for its
      Román, Javier et al.

      Advertised on:

      5
      2021
      Citations
      22
    • The number of globular clusters around the iconic UDG DF44 is as expected for dwarf galaxies
      There is a growing consensus that the vast majority of ultradiffuse galaxies (UDGs) are dwarf galaxies. However, there remain a few UDGs that seem to be special in terms of their globular cluster (GC) systems. In particular, according to some authors, certain UDGs exhibit large GC populations when compared to expectations from their stellar (or
      Saifollahi, Teymoor et al.

      Advertised on:

      4
      2021
      Citations
      47
    • Ultramassive Black Holes in the Most Massive Galaxies: M<SUB>BH</SUB>-σ versus M<SUB>BH</SUB>-R<SUB>b</SUB>
      We investigate the nature of the relations between black hole (BH) mass (M BH) and the central velocity dispersion (σ) and, for core-Sérsic galaxies, the size of the depleted core (R b). Our sample of 144 galaxies with dynamically determined M BH encompasses 24 core-Sérsic galaxies, thought to be products of gas-poor mergers, and reliably
      Dullo, Bililign T. et al.

      Advertised on:

      2
      2021
      Citations
      15
    • Composite bulges - II. Classical bulges and nuclear discs in barred galaxies: the contrasting cases of NGC 4608 and NGC 4643
      We present detailed morphological, photometric, and stellar-kinematic analyses of the central regions of two massive, early-type barred galaxies with nearly identical large-scale morphologies. Both have large, strong bars with prominent inner photometric excesses that we associate with boxy/peanut-shaped (B/P) bulges; the latter constitute ∼30 per
      Erwin, Peter et al.

      Advertised on:

      4
      2021
      Citations
      18

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