The nature of giant clumps in high-z discs: a deep-learning comparison of simulations and observations

Abstract

We use deep learning to explore the nature of observed giant clumps in high-redshift disc galaxies, based on their identification and classification in cosmological simulations. Simulated clumps are detected using the 3D gas and stellar densities in the VELA zoom-in cosmological simulation suite, with $\sim 25\mathrm{pc}$ maximum resolution, targeting main sequence galaxies at $1<z<3$. The clumps are classified as long-lived clumps (LLCs) or short-lived clumps (SLCs) based on their longevity in the simulations. We then train neural networks to detect and classify the simulated clumps in mock, multi-color, dusty and noisy HST-like images. The clumps are detected using an encoder-decoder convolutional neural network (CNN), and are classified according to their longevity using a vanilla CNN. Tests using the simulations show our detector and classifier to be $\sim 80\%$ complete and $\sim 80\%$ pure for clumps more massive than $\sim 10^{7.5}{\mathrm{M}}_{\odot }$. When applied to observed galaxies in the CANDELS/GOODS S+N fields, we find both types of clumps to appear in similar abundances in the simulations and the observations. LLCs are, on average, more massive than SLCs by $\sim 0.5\mathrm{dex}$, and they dominate the clump population above $M_{\mathrm{c}}\gtrsim 10^{7.6}{\mathrm{M}}_{\odot }$. LLCs tend to be found closer to the galactic centre, indicating clump migration to the centre or preferential formation at smaller radii. The LLCs are found to reside in high mass galaxies, indicating better clump survivability under supernova feedback there, due to clumps being more massive in these galaxies. We find the clump properties in the simulations and the observations to agree within a factor of $\sim 2$.

17 pages, 13 figures. Accepted for publication in MNRAS

References in corpus (26)

• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• From rings to bulges: evidence for rapid secular galaxy evolution at z~2 from integral field spectroscopy in the SINS survey
• Compaction and Quenching of High-z Galaxies in Cosmological Simulations: Blue and Red Nuggets
• The rapid formation a large rotating disk galaxy three billion years after the Big Bang
• Rapid formation of exponential disks and bulges at high redshift from the dynamical evolution of clump cluster and chain galaxies
• Intense Star Formation within Resolved Compact Regions in a Galaxy at z=2.3
• Bulge Formation by the Coalescence of Giant Clumps in Primordial Disk Galaxies
• The role of stellar feedback in the formation of galaxies
• Sunrise: Polychromatic Dust Radiative Transfer in Arbitrary Geometries
• Stellar masses from the CANDELS survey: the GOODS-South and UDS fields
• Clumpy Galaxies in CANDELS. I. The Definition of UV Clumps and the Fraction of Clumpy Galaxies at 0.5<z<3
• Unstable disks at high redshift: Evidence for smooth accretion in galaxy formation
• CANDELS Multiwavelength Catalogs: Source Identification and Photometry in the CANDELS COSMOS Survey Field
• z~2: An Epoch of Disk Assembly
• Deep learning predictions of galaxy merger stage and the importance of observational realism
• The nature of giant clumps in distant galaxies probed by the anatomy of the Cosmic Snake
• Diverse Structural Evolution at z > 1 in Cosmologically Simulated Galaxies
• Distinguishing Mergers and Disks in High Redshift Observations of Galaxy Kinematics
• Star Formation and Clumps in Cosmological Galaxy Simulations with Radiation Pressure Feedback
• Rings and Bent Chain Galaxies in the GEMS and GOOD Fields
• Stellar Masses of Giant Clumps in CANDELS and Simulated Galaxies Using Machine Learning
• The role of gas fraction and feedback in the stability and evolution of galactic discs: implications for cosmological galaxy formation models
• Clumpy high-z galaxies as a testbed for feedback-regulated galaxy formation
• Origin of the Golden Mass of Galaxies and Black Holes
• Studying the Physical Properties of Tidal Features I. Extracting Morphological Substructure in CANDELS Observations and VELA Simulations

Cited by in corpus (12)

• The DAWES review 10: The impact of deep learning for the analysis of galaxy surveys
• DeepMerge II: Building Robust Deep Learning Algorithms for Merging Galaxy Identification Across Domains
• The evolution of turbulent galactic discs: gravitational instability, feedback and accretion
• Clump Survival and Migration in VDI Galaxies: an Analytic Model versus Simulations and Observations
• Growth of Massive Black-Holes in FFB Galaxies at Cosmic Dawn
• Effects of feedback on galaxies in the VELA simulations: elongation, clumps and compaction
• Conditions for Clump Survival in High-z Disc Galaxies
• Dark matter cores in massive high-$z$ galaxies formed by baryonic clumps
• UV-Bright Star-Forming Clumps and Their Host Galaxies in UVCANDELS at 0.5 $\le$ z $\le$ 1
• On the origin of compressive turbulence in protoclumps in high redshift disks
• K-Band Imaging of the Nearby, Clumpy Turbulent Disk Galaxy DYNAMO G04-1
• Radial Transport in High-Redshift Disk Galaxies Dominated by Inflowing Streams