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Large Synoptic Survey Telescope White Paper; The Case for Matching U-band on Deep Drilling Fields

Authors:

BW Holwerda, A Baker, S Blyth, S Kannappan, D Obreschkow, S Ravindranath, E Elson, M Vaccari, S Crawford, M Bershady, N Hathi, N Maddox, R Taylor, MATTHEW Jarvis, J Bridge

Abstract:

U-band observations with the LSST have yet to be fully optimized in cadence. The straw man survey design is a simple coverage of the medium-deep-fast survey. Here we argue that deep coverage of the four deep drilling fields (XMM-LSS, ECDFS, ELAIS-S1 and COSMOS) has a much higher scientific return, given that these are also the target of the Southern Hemisphere's Square Kilometer Array Pathfinder, the MeerKAT specifically, deep radio observations.
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MIGHTEE - HI: The relation between the HI gas in galaxies and the cosmic web

Monthly Notices of the Royal Astronomical Society, Volume 513, Issue 2, pp.2168-2177

Authors:

Tudorache, Madalina N. ; Jarvis, M. J. ; Heywood, I. ; Ponomareva, A. A. ; Maddox, N. ; Frank, B. S. ; Adams, N. J. ; Bowler, R. A. A. ; Whittam, I. H. ; Baes, M. ; Pan, H. ; Rajohnson, S. H. A. ; Sinigaglia, F. ; Spekkens, K.

Abstract:

We study the 3D axis of rotation (3D spin) of 77 H I galaxies from the MIGHTEE-H I Early Science observations, and its relation to the filaments of the cosmic web. For this HI-selected sample, the alignment between the spin axis and the closest filament (|cos ψ|) is higher for galaxies closer to the filaments, with ⟨|cos ψ|⟩ = 0.66 ± 0.04 for galaxies <5 Mpc from their closest filament compared to ⟨|cos ψ|⟩ = 0.37 ± 0.08 for galaxies at 5 < d < 10 Mpc. We find that galaxies with a low HI-to-stellar mass ratio (log10(MHI/M⋆) < 0.11) are more aligned with their closest filaments, with ⟨|cos ψ|⟩ = 0.58 ± 0.04; whilst galaxies with (log10(MHI/M⋆) > 0.11) tend to be mis-aligned, with ⟨|cos ψ|⟩ = 0.44 ± 0.04. We find tentative evidence that the spin axis of HI-selected galaxies tend to be aligned with associated filaments (d < 10 Mpc), but this depends on the gas fractions. Galaxies that have accumulated more stellar mass compared to their gas mass tend towards stronger alignment. Our results suggest that those galaxies that have accrued high gas fraction with respect to their stellar mass may have had their spin axis alignment with the filament disrupted by a recent gas-rich merger, whereas the spin vector for those galaxies in which the neutral gas has not been strongly replenished through a recent merger tend to orientate towards alignment with the filament. We also investigate the spin transition between galaxies with a high HI content and a low HI content at a threshold of MHI≈10^9.5M⊙ found in simulations; however, we find no evidence for such a transition with the current data.
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Neural Deprojection of Galaxy Stellar Mass Profiles

Machine Learning and the Physical Sciences Workshop, NeurIPS 2025

Authors:

MJ Yantovski-Barth, H Zhang, N Smyth, C Stone, Martin BUREAU, Y Hezaveh, L Perreault-Levasseur
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SDSS-IV MaNGA: The Different Quenching Histories of Fast and Slow Rotators

MNRAS, 473, 2679

Authors:

Rebecca Smethurst, Karen Masters, Chris Lintott, Anne-Marie Weijmans, Michael Merrifield, Samantha Penny, Alfonso Aragon Salamanca, Joel Brownstein, Kevin Bundy, Niv Drory, David Law, Robert Nichol

Abstract:

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Survey of Gravitationally-lensed Objects in HSC Imaging (SuGOHI). VI. Crowdsourced lens finding with Space Warps

Authors:

Alessandro Sonnenfeld, Aprajita Verma, Anupreeta More, Campbell Allen, Elisabeth Baeten, James HH Chan, Roger Hutchings, Anton T Jaelani, Chien-Hsiu Lee, Christine Macmillan, Philip J Marshall, James O' Donnell, Masamune Oguri, Cristian E Rusu, Marten Veldthuis, Kenneth C Wong, Claude Cornen, Christopher Davis, Adam McMaster, Laura Trouille, Chris Lintott, Grant Miller

Abstract:

Strong lenses are extremely useful probes of the distribution of matter on galaxy and cluster scales at cosmological distances, but are rare and difficult to find. The number of currently known lenses is on the order of 1,000. We wish to use crowdsourcing to carry out a lens search targeting massive galaxies selected from over 442 square degrees of photometric data from the Hyper Suprime-Cam (HSC) survey. We selected a sample of $\sim300,000$ galaxies with photometric redshifts in the range $0.2 < z_{phot} < 1.2$ and photometrically inferred stellar masses $\log{M_*} > 11.2$. We crowdsourced lens finding on this sample of galaxies on the Zooniverse platform, as part of the Space Warps project. The sample was complemented by a large set of simulated lenses and visually selected non-lenses, for training purposes. Nearly 6,000 citizen volunteers participated in the experiment. In parallel, we used YattaLens, an automated lens finding algorithm, to look for lenses in the same sample of galaxies. Based on a statistical analysis of classification data from the volunteers, we selected a sample of the most promising $\sim1,500$ candidates which we then visually inspected: half of them turned out to be possible (grade C) lenses or better. Including lenses found by YattaLens or serendipitously noticed in the discussion section of the Space Warps website, we were able to find 14 definite lenses, 129 probable lenses and 581 possible lenses. YattaLens found half the number of lenses discovered via crowdsourcing. Crowdsourcing is able to produce samples of lens candidates with high completeness and purity, compared to currently available automated algorithms. A hybrid approach, in which the visual inspection of samples of lens candidates pre-selected by discovery algorithms and/or coupled to machine learning is crowdsourced, will be a viable option for lens finding in the 2020s.
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