A5013949214- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Remote Sensing in Agriculture
- Advanced Vision and Imaging
- Gaussian Processes and Bayesian Inference
- Species Distribution and Climate Change
- Metaheuristic Optimization Algorithms Research
- Blind Source Separation Techniques
- Machine Learning and Data Classification
- CCD and CMOS Imaging Sensors
- Atmospheric Ozone and Climate
- Computational Physics and Python Applications
- Computer Graphics and Visualization Techniques
- Time Series Analysis and Forecasting
- Spectroscopy and Chemometric Analyses
- Photocathodes and Microchannel Plates
- Data Visualization and Analytics
- Anomaly Detection Techniques and Applications
- Advanced Fluorescence Microscopy Techniques
- Statistics Education and Methodologies
- Remote Sensing and LiDAR Applications
- Semiconductor Lasers and Optical Devices
Canadian Institute for Theoretical Astrophysics
2025
University of Toronto
2025
University of Oxford
2020-2023
We present Galaxy Zoo DECaLS: detailed visual morphological classifications for Dark Energy Camera Legacy Survey images of galaxies within the SDSS DR8 footprint. Deeper DECaLS (r=23.6 vs. r=22.2 from SDSS) reveal spiral arms, weak bars, and tidal features not previously visible in imaging. To best exploit greater depth images, volunteers select a new set answers designed to improve our sensitivity mergers bars. provide 7.5 million individual over 314,000 galaxies. 140,000 receive at least...
Astronomers have typically set out to solve supervised machine learning problems by creating their own representations from scratch. We show that deep models trained answer every Galaxy Zoo DECaLS question learn meaningful semantic of galaxies are useful for new tasks on which the were never trained. exploit these outperform several recent approaches at practical crucial investigating large galaxy samples. The first task is identifying similar morphology a query galaxy. Given single assigned...
ABSTRACT We study the bar pattern speeds and corotation radii of 225 barred galaxies, using integral field unit data from MaNGA Tremaine–Weinberg method. Our sample, which is divided between strongly weakly galaxies identified via Galaxy Zoo, largest that this method has been applied to. find lower for than galaxies. As simulations show speed decreases as exchanges angular momentum with its host, these results suggest strong bars are more evolved weak bars. Interestingly, radius not...
ABSTRACT We present detailed morphology measurements for 8.67 million galaxies in the DESI Legacy Imaging Surveys (DECaLS, MzLS, and BASS, plus DES). These are automated made by deep learning models trained on Galaxy Zoo volunteer votes. Our typically predict fraction of volunteers selecting each answer to within 5–10 per cent every GZ question. The newly collected votes DESI-LS DR8 images as well historical from DECaLS. also release Extending our outside previously released DECaLS/SDSS...
Abstract Active galactic nucleus (AGN) growth in disk-dominated, merger-free galaxies is poorly understood, largely due to the difficulty disentangling AGN emission from that of host galaxy. By carefully separating this emission, we examine differences between AGNs hosting a (possibly) merger-grown, classical bulge, and secularly grown, truly bulgeless disk galaxies. We use Galfit obtain robust, accurate morphologies 100 disk-dominated imaged with Hubble Space Telescope. Adopting an...
Abstract We have not yet observed the epoch at which disc galaxies emerge in Universe. While high-z measurements of large-scale features such as bars and spiral arms trace evolution galaxies, methods cannot directly quantify featureless discs early Here we identify a substantial population apparently Cosmic Evolution Early Release Science (CEERS) survey by combining quantitative visual morphologies ∼7000 from Galaxy Zoo JWST CEERS project with public catalogue expert parametric morphologies....
Abstract Galaxy interaction and merging have clear effects on the systems involved. We find an increase in star formation rate (SFR), potential ignition of active galactic nuclei (AGN) significant morphology changes. However, at what stage during interactions or mergers these changes begin to occur remains open question. With a combination machine learning visual classification, we select sample 3,162 interacting galaxies Cosmic Evolutionary Survey (COSMOS) field across redshift range 0.0 -...
ABSTRACT We have used Galaxy Zoo DECaLS (GZD) to study strong and weak bars in disc galaxies. Out of the 314 000 galaxies GZD, we created a volume-limited sample (0.01 < z 0.05, Mr − 18.96) which contains 1867 with reliable volunteer bar classifications ALFALFA footprint. In keeping previous surveys (such as GZ2), morphological from GZD agree well surveys. considers either (15.5 per cent), (28.1 cent) or no (56.4 based on images obtained survey. This places unique position assess...
ABSTRACT Most secular effects produced by stellar bars strongly depend on the pattern speed. Unfortunately, it is also most difficult observational parameter to estimate. In this work, we measured bar speed of 97 Milky-Way analogue galaxies from MaNGA survey using Tremaine–Weinberg method. The sample was selected constraining mass and morphological type. We improve our measurements weighting three independent estimates disc position angle. To recover rotation curve, fit a kinematic model H α...
We present the first systematic investigation of supervised scaling laws outside an ImageNet-like context - on images galaxies. use 840k galaxy and over 100M annotations by Galaxy Zoo volunteers, comparable in scale to Imagenet-1K. find that adding annotated provides a power law improvement performance across all architectures tasks, while trainable parameters is effective only for some (typically more subjectively challenging) tasks. then compare downstream finetuned models pretrained...
ABSTRACT The role of large-scale bars in the fuelling active galactic nuclei (AGNs) is still debated, even as evidence mounts that black hole growth absence galaxy mergers cumulatively dominates and may substantially influence disc (i.e. merger-free) evolution. We investigate whether are a good candidate for merger-free AGN fuelling. Specifically, we combine slit spectroscopy Hubble Space Telescope imagery to characterize star formation rates (SFRs) stellar masses unambiguously...
Understanding the effect spiral structure has on star formation properties of galaxies is important to completing our picture evolution. Previous studies have investigated connections between arm with formation, but that number arms this process unclear. Here we use Galaxy and Mass Assembly (GAMA) survey paired citizen science visual classifications from Zoo project explore galaxies' how it connects process. We votes GAMA-KiDS GalaxyZoo classification investigate link stellar mass, rate,...
Abstract We study how bar strength and kinematics affect star formation in different regions of the by creating radial profiles EW[H α ] D n 4000 using data from Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at Apache Point Observatory (MaNGA). Bars galaxies are classified as strong or weak Galaxy Zoo DESI, they fast slow bars Tremaine–Weinberg method on stellar kinematic MaNGA survey. In agreement with previous studies, we find that star-forming (SF) have enhanced their center beyond...
ABSTRACT Galaxies fall broadly into two categories: star-forming (blue) galaxies and quiescent (red) galaxies. In between, one finds the less populated ‘green valley’. Some of these are suspected to be in process ceasing their star formation through a gradual exhaustion gas supply, or already dead experiencing rejuvenation fuel injection. We use Galaxy And Mass Assembly (GAMA) database Zoo citizen science morphological estimates compare morphology green valley with those red sequence blue...
The galaxy population is strongly bimodal in both colour and morphology, the two measures correlate strongly, with most blue galaxies being late-types (spirals) early-types, typically ellipticals, red. This observation has led to use of as a convenient selection criteria make samples which are then labelled by morphology. Such proxy for morphology results necessarily impure incomplete samples. In this paper, we morphological labels produced Galaxy Zoo measure how such are, considering...
Mergers play a complex role in galaxy formation and evolution. Continuing to improve our understanding of these systems require ever larger samples, which can be difficult (even impossible) select from individual surveys. We use the new platform ESA Datalabs assemble catalogue interacting galaxies Hubble Space Telescope science archives; this is than previously published catalogues by nearly an order magnitude. In particular, we apply Zoobot convolutional neural network directly entire...
Long GRB hosts at z<1 are usually low-mass, low metallicity star-forming galaxies. Here we present the until now most detailed, spatially resolved study of host 171205A, a grand-design barred spiral galaxy z=0.036. Our analysis includes MUSE integral field spectroscopy, complemented by high spatial resolution UV/VIS HST imaging and CO(1-0) HI 21cm data. The is located in small region arm deprojected distance ~ 8 kpc from center. shows smooth negative gradient site half solar, slightly below...
We study how bar strength and kinematics affect star formation in different regions of the by creating radial profiles EW[H$\alpha$] D$_{\rm n}$4000 using data from SDSS-IV MaNGA. Bars galaxies are classified as strong or weak Galaxy Zoo DESI, they fast slow bars Tremaine-Weinberg method on stellar kinematic MaNGA survey. In agreement with previous studies, we find that forming have enhanced their centre beyond bar-end region, while is suppressed arms bar. This not found for weakly barred...
Active galactic nucleus (AGN) growth in disk-dominated, merger-free galaxies is poorly understood, largely due to the difficulty disentangling AGN emission from that of host galaxy. By carefully separating this emission, we examine differences between AGNs hosting a (possibly) merger-grown, classical bulge, and secularly grown, truly bulgeless disk galaxies. We use GALFIT obtain robust, accurate morphologies 100 disk-dominated imaged with Hubble Space Telescope. Adopting an inclusive...
We study the bar pattern speeds and corotation radii of 225 barred galaxies, using IFU data from MaNGA Tremaine-Weinberg method. Our sample, which is divided between strongly weakly galaxies identified via Galaxy Zoo, largest that this method has been applied to. find lower for than galaxies. As simulations show speed decreases as exchanges angular momentum with its host, these results suggest strong bars are more evolved weak bars. Interestingly, radius not different despite being...
Mergers play a complex role in galaxy formation and evolution. Continuing to improve our understanding of these systems require ever larger samples, which can be difficult (even impossible) select from individual surveys. We use the new platform ESA Datalabs assemble catalogue interacting galaxies Hubble Space Telescope science archives; this is than previously published catalogues by nearly an order magnitude. In particular, we apply Zoobot convolutional neural network directly entire...
The role of large-scale bars in the fuelling active galactic nuclei (AGN) is still debated, even as evidence mounts that black hole growth absence galaxy mergers cumulatively dominated and may substantially influence disc (i.e., merger-free) evolution. We investigate whether are a good candidate for merger-free AGN fuelling. Specifically, we combine slit spectroscopy Hubble Space Telescope imagery to characterise star formation rates (SFRs) stellar masses unambiguously disc-dominated host...