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Galaxy Morphological Classification Catalogue of the Dark Energy Survey Year 3 data with Convolutional Neural Networks (2021)
Journal Article
Cheng, T.-Y., Conselice, C. J., Aragón-Salamanca, A., Aguena, M., Allam, S., Andrade-Oliveira, F., Annis, J., Bluck, A. F. L., Brooks, D., Burke, D. L., Kind, M. C., Carretero, J., Choi, A., Costanzi, M., da Costa, L. N., Pereira, M. E. S., De Vicente, J., Diehl, H. T., Drlica-Wagner, A., Eckert, K., …To, C. (2021). Galaxy Morphological Classification Catalogue of the Dark Energy Survey Year 3 data with Convolutional Neural Networks. Monthly Notices of the Royal Astronomical Society, 507(3), 4425-4444. https://doi.org/10.1093/mnras/stab2142

We present in this paper one of the largest galaxy morphological classification catalogues to date, including over 20 million of galaxies, using the Dark Energy Survey (DES) Year 3 data based on Convolutional Neural Networks (CNN). Monochromatic i-ba... Read More about Galaxy Morphological Classification Catalogue of the Dark Energy Survey Year 3 data with Convolutional Neural Networks.

Beyond the Hubble Sequence - Exploring Galaxy Morphology with Unsupervised Machine Learning (2021)
Journal Article
Cheng, T.-Y., Huertas-Company, M., Conselice, C. J., Aragón-Salamanca, A., Robertson, B. E., & Ramachandra, N. (2021). Beyond the Hubble Sequence - Exploring Galaxy Morphology with Unsupervised Machine Learning. Monthly Notices of the Royal Astronomical Society, 503(3), 4446-4465. https://doi.org/10.1093/mnras/stab734

We explore unsupervised machine learning for galaxy morphology analyses using a combination of feature extraction with a vector-quantised variational autoencoder (VQ-VAE) and hierarchical clustering (HC). We propose a new methodology that includes: (... Read More about Beyond the Hubble Sequence - Exploring Galaxy Morphology with Unsupervised Machine Learning.

Cosmic filaments in galaxy cluster outskirts: quantifying finding filaments in redshift space (2021)
Journal Article
Kuchner, U., Aragón-Salamanca, A., Rost, A., Pearce, F. R., Gray, M. E., Cui, W., Knebe, A., Rasia, E., & Yepes, G. (2021). Cosmic filaments in galaxy cluster outskirts: quantifying finding filaments in redshift space. Monthly Notices of the Royal Astronomical Society, 503(2), 2065-2076. https://doi.org/10.1093/mnras/stab567

Inferring line-of-sight distances from redshifts in and around galaxy clusters is complicated by peculiar velocities, a phenomenon known as the "Fingers of God" (FoG). This presents a significant challenge for finding filaments in large observational... Read More about Cosmic filaments in galaxy cluster outskirts: quantifying finding filaments in redshift space.

Size, shade or shape? The contribution of galaxies of different types to the star-formation history of the Universe from SDSS-IV MaNGA (2021)
Journal Article
Peterken, T., Aragón-Salamanca, A., Merrifield, M., Avila-Reese, V., Boardman, N. F., Sánchez, H. D., Bizyaev, D., Drory, N., Pan, K., & Brownstein, J. R. (2021). Size, shade or shape? The contribution of galaxies of different types to the star-formation history of the Universe from SDSS-IV MaNGA. Monthly Notices of the Royal Astronomical Society, 502(3), 3128–3143. https://doi.org/10.1093/mnras/stab268

SDSS-IV MaNGA: the “G-dwarf problem” revisited (2021)
Journal Article
Greener, M. J., Merrifield, M., Aragón-Salamanca, A., Peterken, T., Andrews, B., & Lane, R. R. (2021). SDSS-IV MaNGA: the “G-dwarf problem” revisited. Monthly Notices of the Royal Astronomical Society: Letters, 502(1), L95–L98. https://doi.org/10.1093/mnrasl/slab012

The levels of heavy elements in stars are the product of enhancement by previous stellar generations, and the distribution of this metallicity among the population contains clues to the process by which a galaxy formed. Most famously, the “G-dwarf pr... Read More about SDSS-IV MaNGA: the “G-dwarf problem” revisited.

SDSS-IV MaNGA: when is morphology imprinted on galaxies? (2020)
Journal Article
Peterken, T., Merrifield, M., Aragón-Salamanca, A., Avila-Reese, V., Boardman, N. F., Drory, N., & Lane, R. R. (2021). SDSS-IV MaNGA: when is morphology imprinted on galaxies?. Monthly Notices of the Royal Astronomical Society: Letters, 500(1), L42-L46. https://doi.org/10.1093/mnrasl/slaa179

It remains an open question as to how long ago the morphology that we see in a present-day galaxy was typically imprinted. Studies of galaxy populations at different redshifts reveal that the balance of morphologies has changed over time, but such sn... Read More about SDSS-IV MaNGA: when is morphology imprinted on galaxies?.

SDSS-IV MaNGA: The link between bars and the early cessation of star formation in spiral galaxies (2020)
Journal Article
Fraser-McKelvie, A., Merrifield, M., Aragón-Salamanca, A., Peterken, T., Kraljic, K., Masters, K., Stark, D., Fragkoudi, F., Smethurst, R., Boardman, N. F., Drory, N., & Lane, R. R. (2020). SDSS-IV MaNGA: The link between bars and the early cessation of star formation in spiral galaxies. Monthly Notices of the Royal Astronomical Society, 499(1), 1116-1125. https://doi.org/10.1093/mnras/staa2866

Bars are common in low-redshift disc galaxies, and hence quantifying their influence on their host is of importance to the field of galaxy evolution. We determine the stellar populations and star formation histories of 245 barred galaxies from the Ma... Read More about SDSS-IV MaNGA: The link between bars and the early cessation of star formation in spiral galaxies.

Formation of S0s in extreme environments II: the star-formation histories of bulges, discs and lenses (2020)
Journal Article
Johnston, E. J., Aragón-Salamanca, A., Fraser-McKelvie, A., Merrifield, M., Häußler, B., Coccato, L., Jaffé, Y., Cortesi, A., Chies-Santos, A., Rodríguez Del Pino, B., & Sheen, Y.-K. (2021). Formation of S0s in extreme environments II: the star-formation histories of bulges, discs and lenses. Monthly Notices of the Royal Astronomical Society, 500(3), 4193-4212. https://doi.org/10.1093/mnras/staa2838

Different processes have been proposed to explain the formation of S0s, including mergers, disc instabilities, and quenched spirals. These processes are expected to dominate in different environments, and thus leave characteristic footprints in the k... Read More about Formation of S0s in extreme environments II: the star-formation histories of bulges, discs and lenses.

SDSS-IV MaNGA: spatially resolved star formation in barred galaxies (2020)
Journal Article
Fraser-McKelvie, A., Aragón-Salamanca, A., Merrifield, M., Masters, K., Nair, P., Emsellem, E., Kraljic, K., Krishnarao, D., Andrews, B. H., Drory, N., & Neumann, J. (2020). SDSS-IV MaNGA: spatially resolved star formation in barred galaxies. Monthly Notices of the Royal Astronomical Society, 495(4), 4158-4169. https://doi.org/10.1093/mnras/staa1416

Bars inhabit the majority of local-Universe disc galaxies and may be important drivers of galaxy evolution through the redistribution of gas and angular momentum within discs. We investigate the star formation and gas properties of bars in galaxies s... Read More about SDSS-IV MaNGA: spatially resolved star formation in barred galaxies.

SDSS-IV MaNGA: Excavating the fossil record of stellar populations in spiral galaxies (2020)
Journal Article
Peterken, T., Merrifield, M., Aragón-Salamanca, A., Fraser-McKelvie, A., Avila-Reese, V., Riffel, R., Knapen, J., & Drory, N. (2020). SDSS-IV MaNGA: Excavating the fossil record of stellar populations in spiral galaxies. Monthly Notices of the Royal Astronomical Society, 495(3), 3387-3402. https://doi.org/10.1093/mnras/staa1303

We perform a 'fossil record' analysis for ≈800 low-redshift spiral galaxies, using starlight applied to integral field spectroscopic observations from the SDSS-IV MaNGA survey to obtain fully spatially resolved high-resolution star formation historie... Read More about SDSS-IV MaNGA: Excavating the fossil record of stellar populations in spiral galaxies.

Mapping and characterization of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations (2020)
Journal Article
Kuchner, U., Aragón-Salamanca, A., Pearce, F. R., Gray, M. E., Rost, A., Mu, C., Welker, C., Cui, W., Haggar, R., Laigle, C., Knebe, A., Kraljic, K., Sarron, F., & Yepes, G. (2020). Mapping and characterization of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations. Monthly Notices of the Royal Astronomical Society, 494(4), 5473-5491. https://doi.org/10.1093/mnras/staa1083

Upcoming wide-field surveys are well-suited to studying the growth of galaxy clusters by tracing galaxy and gas accretion along cosmic filaments. We use hydrodynamic simulations of volumes surrounding 324 clusters from The ThreeHundred project to dev... Read More about Mapping and characterization of cosmic filaments in galaxy cluster outskirts: strategies and forecasts for observations from simulations.

Identifying Strong Lenses with Unsupervised Machine Learning using Convolutional Autoencoder (2020)
Journal Article
Cheng, T.-Y., Li, N., Conselice, C. J., Aragón-Salamanca, A., Dye, S., & Metcalf, R. B. (2020). Identifying Strong Lenses with Unsupervised Machine Learning using Convolutional Autoencoder. Monthly Notices of the Royal Astronomical Society, 394(3), 3750–3765. https://doi.org/10.1093/mnras/staa1015

In this paper we develop a new unsupervised machine learning technique comprised of a feature extractor, a convolutional autoencoder (CAE), and a clustering algorithm consisting of a Bayesian Gaussian mixture model (BGM). We apply this technique to v... Read More about Identifying Strong Lenses with Unsupervised Machine Learning using Convolutional Autoencoder.

Optimizing automatic morphological classification of galaxies with machine learning and deep learning using Dark Energy Survey imaging (2020)
Journal Article
Cheng, T.-Y., Conselice, C. J., Aragón-Salamanca, A., Li, N., Bluck, A. F., Hartley, W. G., Annis, J., Brooks, D., Doel, P., García-Bellido, J., James, D. J., Kuehn, K., Kuropatkin, N., Smith, M., Sobreira, F., & Tarle, G. (2020). Optimizing automatic morphological classification of galaxies with machine learning and deep learning using Dark Energy Survey imaging. Monthly Notices of the Royal Astronomical Society, 493(3), 4209-4228. https://doi.org/10.1093/mnras/staa501

There are several supervised machine learning methods used for the application of automated morphological classification of galaxies; however, there has not yet been a clear comparison of these different methods using imaging data, or a investigation... Read More about Optimizing automatic morphological classification of galaxies with machine learning and deep learning using Dark Energy Survey imaging.

Preprocessing among the Infalling Galaxy Population of EDisCS Clusters (2019)
Journal Article
Kirby, M., Just, D. W., Zaritsky, D., Rudnick, G., Desjardins, T., Cool, R., Moustakas, J., Clowe, D., Lucia, G. D., Aragón-Salamanca, A., Desai, V., Finn, R., Halliday, C., Jablonka, P., Mann, J., Poggianti, B., Bian, F.-Y., & Liebst, K. (2019). Preprocessing among the Infalling Galaxy Population of EDisCS Clusters. Astrophysical Journal, 885(1), Article 6. https://doi.org/10.3847/1538-4357/ab44a0

We present results from a low-resolution spectroscopic survey for 21 galaxy clusters at 0.4 < z < 0.8 selected from the ESO Distant Cluster Survey. We measured spectra using the low-dispersion prism in IMACS on the Magellan Baade telescope and calcul... Read More about Preprocessing among the Infalling Galaxy Population of EDisCS Clusters.

From the outside looking in: what can Milky Way Analogues tell us about the star formation rate of our own galaxy? (2019)
Journal Article
Fraser-Mckelvie, A., Merrifield, M., & Aragón-Salamanca, A. (2019). From the outside looking in: what can Milky Way Analogues tell us about the star formation rate of our own galaxy?. Monthly Notices of the Royal Astronomical Society, 489(4), 5030–5036. https://doi.org/10.1093/mnras/stz2493

The Milky Way has been described as an anaemic spiral, but is its star formation rate (SFR) unusually low when compared to its peers? To answer this question, we define a sample of Milky Way Analogues (MWAs) based on stringent cuts on the best litera... Read More about From the outside looking in: what can Milky Way Analogues tell us about the star formation rate of our own galaxy?.

Time-slicing spiral galaxies with SDSS-IV MaNGA (2019)
Journal Article
Peterken, T., Fraser-Mckelvie, A., Aragón-Salamanca, A., Merrifield, M., Kraljic, K., Knapen, J. H., Riffel, R., Brownstein, J., & Drory, N. (2019). Time-slicing spiral galaxies with SDSS-IV MaNGA. Monthly Notices of the Royal Astronomical Society, 489(1), 1338–1343. https://doi.org/10.1093/mnras/stz2204/5548799

Spectra of galaxies contain a wealth of information about the stellar populations from which they are made. With integral-field unit (IFU) surveys, such data can be used to map out stellar population properties across the face of a galaxy, allowing o... Read More about Time-slicing spiral galaxies with SDSS-IV MaNGA.

Signatures of stellar accretion in MaNGA early-type galaxies (2019)
Journal Article
Oyarzún, G. A., Bundy, K., Westfall, K. B., Belfiore, F., Thomas, D., Maraston, C., Lian, J., Aragón-Salamanca, A., Zheng, Z., Gonzalez-Perez, V., Law, D. R., Drory, N., & Andrews, B. H. (2019). Signatures of stellar accretion in MaNGA early-type galaxies. Astrophysical Journal, 880(2), Article 111. https://doi.org/10.3847/1538-4357/ab297c

The late assembly of massive galaxies is thought to be dominated by stellar accretion in their outskirts (beyond 2 effective radii R e) due to dry, minor galaxy mergers. We use observations of 1010 passive early-type galaxies (ETGs) within z < 0.15 f... Read More about Signatures of stellar accretion in MaNGA early-type galaxies.

SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies (2019)
Journal Article
Fraser-McKelvie, A., Merrifield, M., Aragón-Salamanca, A., Peterken, T., Masters, K., Krawczyk, C., Andrews, B., Knapen, J. H., Kruk, S., Schaefer, A., Smethurst, R., Riffel, R., Brownstein, J., & Drory, N. (2019). SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies. Monthly Notices of the Royal Astronomical Society: Letters, 488(1), L6–L11. https://doi.org/10.1093/mnrasl/slz085

Bars in galaxies are thought to stimulate both inflow of material and radial mixing along them. Observational evidence for this mixing has been inconclusive so far however, limiting the evaluation of the impact of bars on galaxy evolution. We now use... Read More about SDSS-IV MaNGA: Stellar Population Gradients Within Barred Galaxies.

The time delay between star formation quenching and morphological transformation of galaxies in clusters: a phase–space view of EDisCS (2019)
Journal Article
Kelkar, K., Gray, M. E., Aragón-Salamanca, A., Rudnick, G., Jaffé, Y. L., Jablonka, P., Moustakas, J., & Milvang-Jensen, B. (2019). The time delay between star formation quenching and morphological transformation of galaxies in clusters: a phase–space view of EDisCS. Monthly Notices of the Royal Astronomical Society, 486(1), 868-884. https://doi.org/10.1093/mnras/stz905

We explore the possible effect of cluster environments on the structure and star formation histories of galaxies by analysing the projected phase–space (PPS) of intermediate-redshift clusters (0.4 z 0.8). HST I−band imaging data from the ESO Distant... Read More about The time delay between star formation quenching and morphological transformation of galaxies in clusters: a phase–space view of EDisCS.