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

    • 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.

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      11
      2023
      Citations
      7
    • 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.

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      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.

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      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
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    • 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
      4
    • 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.

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      1
      2023
      Citations
      11
    • Mapping non-axisymmetric velocity fields of external galaxies
      Disc galaxies are typically in a stable configuration where matter moves in almost closed circular orbits. However, non-circular motions caused by distortions, warps, lopsidedness, or satellite interactions are common and leave distinct signatures on galaxy velocity maps. We develop an algorithm that uses an ordinary least squares method for
      Sylos Labini, Francesco et al.

      Advertised on:

      9
      2023
      Citations
      1
    • Flares, Warps, Truncations, and Satellite: The Ultra-thin Galaxy UGC 11859
      The structure of the outskirts of galaxies provides valuable information about their past and evolution. Due to their projected orientation, edge-on isolated galaxies effectively serve as test labs in which to study the three-dimensional structures of galaxies, including warps and flares, and to explore the possible sources of such distortions. We
      Ossa-Fuentes, Luis et al.

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      7
      2023
      Citations
      3
    • Extragalactic Magnetism with SOFIA (SALSA Legacy Program). V. First Results on the Magnetic Field Orientation of Galaxies
      We present the analysis of the magnetic field (B-field) structure of galaxies measured with far-infrared (FIR) and radio (3 and 6 cm) polarimetric observations. We use the first data release of the Survey of extragALactic magnetiSm with SOFIA of 14 nearby ( $\lt 20$ Mpc) galaxies with resolved ( $5^{\prime\prime} \mbox{--}18^{\prime\prime} ;$ 90 pc
      Borlaff, Alejandro S. et al.

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      7
      2023
      Citations
      10
    • The massive relic galaxy NGC 1277 is dark matter deficient. From dynamical models of integral-field stellar kinematics out to five effective radii
      According to the Λ cold dark matter (ΛCDM) cosmology, present-day galaxies with stellar masses M ⋆ > 10 11 M ⊙ should contain a sizable fraction of dark matter within their stellar body. Models indicate that in massive early-type galaxies (ETGs) with M ⋆ ≈ 1.5 × 10 11 M ⊙, dark matter should account for ∼15% of the dynamical mass within one
      Comerón, Sébastien et al.

      Advertised on:

      7
      2023
      Citations
      22
    • LeMMINGs. V. Nuclear activity and bulge properties: A detailed multi-component decomposition of e-MERLIN Palomar galaxies with HST
      We used high-resolution HST imaging and e-MERLIN 1.5-GHz observations of galaxy cores from the LeMMINGs survey to investigate the relation between optical structural properties and nuclear radio emission for a large sample of galaxies. We performed accurate, multi-component decompositions of new surface brightness profiles extracted from HST images
      Dullo, B. T. et al.

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      7
      2023
      Citations
      2
    • Fully adaptive Bayesian algorithm for data analysis: FABADA
      The discovery potential from astronomical and other data is limited by their noise. We introduce a novel non-parametric noise reduction technique based on Bayesian inference techniques, fully adaptive Bayesian algorithm for data analysis (FABADA) that automatically improves the signal-to-noise ratio of one- and two-dimensional data, such as
      Sánchez-Alarcón, Pablo M. et al.

      Advertised on:

      1
      2023
      Citations
      5
    • The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. VI. The Star Formation History and Dust Production in Andromeda IX
      We present a photometric study of the resolved stellar populations in Andromeda IX (And IX), the closest satellite to M31, a metal-poor and low-mass dwarf spheroidal galaxy. We estimate a distance modulus of ${24.56}_{-0.15}^{+0.05}$ mag based on the tip of the red giant branch. By probing the variability of asymptotic giant branch stars, we study
      Abdollahi, Hedieh et al.

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      5
      2023
      Citations
      0
    • LeMMINGs. VI. Connecting nuclear activity to bulge properties of active and inactive galaxies: radio scaling relations and galaxy environment
      Multiwavelength studies indicate that nuclear activity and bulge properties are closely related, but the details remain unclear. To study this further, we combine Hubble Space Telescope bulge structural and photometric properties with 1.5 GHz, e-MERLIN nuclear radio continuum data from the LeMMINGs survey for a large sample of 173 'active' galaxies
      Dullo, B. T. et al.

      Advertised on:

      7
      2023
      Citations
      3
    • Sociology and hierarchy of voids: A study of seven nearby CAVITY galaxy voids and their dynamical CosmicFlows-3 environment
      Context. The present study addresses a key question related to our understanding of the relation between void galaxies and their environment: the relationship between luminous and dark matter in and around voids. Aims: To explore the extent to which local Universe voids are empty of matter, we study the full (dark+luminous) matter content of seven
      Courtois, H. M. et al.

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      5
      2023
      Citations
      3
    • Identification of tidal features in deep optical galaxy images with convolutional neural networks
      Interactions between galaxies leave distinguishable imprints in the form of tidal features, which hold important clues about their mass assembly. Unfortunately, these structures are difficult to detect because they are low surface brightness features, so deep observations are needed. Upcoming surveys promise several orders of magnitude increase in
      Domínguez Sánchez, H. et al.

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      5
      2023
      Citations
      15
    • MaNGIA: 10 000 mock galaxies for stellar population analysis
      Context. Modern astronomical observations give unprecedented access to the physical properties of nearby galaxies, including spatially resolved stellar populations. However, observations can only give a present-day view of the Universe, whereas cosmological simulations give access to the past record of the processes that galaxies have experienced
      Sarmiento, Regina et al.

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      5
      2023
      Citations
      17
    • MIGHTEE-H I: possible interactions with the galaxy NGC 895
      The transformation and evolution of a galaxy is strongly influenced by interactions with its environment. Neutral hydrogen (H I) is an excellent way to trace these interactions. Here, we present H I observations of the spiral galaxy NGC 895, which was previously thought to be isolated. High-sensitivity H I observations from the MeerKAT large survey
      Namumba, B. et al.

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      6
      2023
      Citations
      0
    • WEAVE-StePS: A stellar population survey using WEAVE at WHT
      Context. The upcoming new generation of optical spectrographs on four-meter-class telescopes will provide valuable opportunities for forthcoming galaxy surveys through their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage. Aims: WEAVE is a new wide-field spectroscopic facility mounted on the 4.2
      Iovino, A. et al.

      Advertised on:

      4
      2023
      Citations
      7
    • Hidden depths in the local Universe: The Stellar Stream Legacy Survey
      Context. Mergers and tidal interactions between massive galaxies and their dwarf satellites are a fundamental prediction of the Lambda-cold dark matter cosmology. These events are thought to provide important observational diagnostics of non-linear structure formation. Stellar streams in the Milky Way and Andromeda are spectacular evidence for
      Martínez-Delgado, David et al.

      Advertised on:

      3
      2023
      Citations
      53

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