arXiv subjects

Garreth Martin

Publications and source records attributed to Garreth Martin.

At least 19 recordsLinked to original sources

arXiv2026

Global trends in morphology from massive to dwarf galaxies

The morphological properties of dwarf galaxies (Mstar < 10^9.5 MSun) remain largely unexplored, particularly outside the local neighbourhood. We explore how morphology changes across the massive to dwarf-galaxy regimes, using a mass-complete sample of ~1000 galaxies, with stellar masses and redshifts in the ranges 10^7 MSun < Mstar < 10^12 MSun and z < 0.15 respectively. By combining JWST-derived morphological parameters (concentration, asymmetry and clumpiness; `CAS') and visual morphological classifications, we explore: (1) how morphology changes with stellar mass and effective surface brightness, (2) the connection between morphology and recent star formation history, as a function of stellar mass, (3) how bar frequency changes between the massive and dwarf regimes and (4) how well the CAS parameters perform in separating early- and late-type galaxies, as a function of stellar mass. We demonstrate that galaxies become less concentrated, more asymmetric and less clumpy with decreasing stellar mass. In both mass regimes, galaxies that are more concentrated and less asymmetric are more likely to be red (i.e. quenched). The decrease in concentration towards lower stellar masses results in a loss of the leverage that this parameter can provide in separating early- and late-type galaxies. Thus, while the CAS system successfully separates early- and late-type systems in the massive-galaxy regime, these morphological classes become significantly more difficult to separate, using these parameters, in the dwarf regime. Finally, the bar fraction declines steadily with decreasing stellar mass and becomes consistent with zero at Mstar ~ 10^8 MSun, suggesting a lower limit for the galaxy mass needed to induce bar formation.

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arXiv2026

A Consistent Comparison of Intracluster Light Assembly in Simulations I. Redshift Evolution and Progenitor Galaxies

The tidal stripping of satellite galaxies and the stellar detritus ejected during galaxy mergers builds up a diffuse stellar component in galaxy clusters known as the intracluster light (ICL). We investigate ICL assembly in cluster-mass haloes ($M_{178c}\sim10^{14}-10^{15}$ M$_\odot$) using four different hydrodynamical simulations (Horizon-AGN, TNG100, The Three Hundred Gizmo-Simba 7K, and Hydrangea) under a homogenized ICL identification framework. For our fiducial ICL definition we obtain broadly consistent $z\approx0$ ICL stellar mass fractions ($\sim0.1-0.2$) and, by tracking the progenitors of $z\approx0$ clusters back to $z\gtrsim2$, find no significant evolution in average ICL mass fractions. Alternative approaches for distinguishing the ICL from the central galaxy show the absolute ICL fraction to be highly sensitive to adopted definition, but we never find any significant inter-simulation discrepancies when implementing a consistent methodology to identify the ICL. Whether the average ICL mass fraction falls with increasing redshift or does not evolve is determined by the ICL definition adopted. By tracing $z\approx0$ ICL stars back to their progenitor galaxies, we find that lower-mass satellites typically make slightly larger ICL contributions relative to their mass in every considered simulation, but which galaxies make the dominant contribution to the ICL is primarily controlled by the infalling satellite mass function. Most ICL stars sourced from satellite galaxies are therefore expected to originate from galaxies with infall stellar masses above $\sim10^{10}$ M$_\odot$ and largely within $10^{10.5}-10^{11.5}$ M$_\odot$.

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arXiv2026

Intracluster light is a close tracer of the dark matter halo shape

We investigate whether the intracluster light (ICL) can serve as a reliable tracer of the shape of the underlying dark matter (DM) haloes in galaxy clusters. Using the cosmological Hydrangea cluster simulations, we measure the 3D and projected shapes of both components with a shape tensor computed in concentric ellipsoidal shells, out to the virial radius $R_\mathrm{200c}$ for each cluster. The ICL and DM are closely aligned, with their major axes typically offset from each other by $\lesssim$10 degrees. Their axis ratios also match closely, with a typical difference of only $\approx\! 0.07$ for both the major-to-minor and major-to-intermediate axes, the DM being slightly rounder than the ICL. These trends are consistent across 2D and 3D measurements and agree well with results from isophotal fitting of mock images. In detail, the axis ratio offset is sensitive to the method used to remove satellites, and may also depend on the choice of subgrid physics models. We demonstrate that the ICL traces the DM shape better than the distribution of satellite galaxies, which exhibits larger scatter in the axis ratio and misalignment angle and is overall more elliptical. Together, these results indicate that the ICL can act as a useful proxy for DM halo ellipticity and orientation.

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arXiv2026

LIGHTS. The Thin Encircling Stellar Stream of NGC 3938

We present a stellar stream found in images of the nearby, nearly face-on, late-type galaxy, NGC 3938 obtained for the LBT Imaging of Galactic Halos and Tidal Structures (LIGHTS) survey that is thin, has very low mean surface brightness ($\langle\mu_g\rangle \approx$ 28.7 mag arcsec$^{-2}$ and $\langle\mu_r\rangle \approx$ 28.1 mag arcsec$^{-2}$), appears to lie nearly on the plane of the sky, and wraps more than half way around a host galaxy that is otherwise apparently isolated. We estimate that the progenitor had a stellar mass of $\sim 3.7\times 10^7$ M$_\odot$. Despite an intriguing apparent offset between the centroid of the host galaxy and the apparent center of the stream orbit, we find that we can reproduce the morphology, including this apparent off-centering, with simple models and standard assumptions about the host (thin disk centered within a canonical spherical dark matter halo) and the progenitor satellite orbit. We identify a number of detailed features of the stream, such as changes in curvature and density, that will require more complex models to reproduce. Even this rather simple system provides a rich set of constraints with which to explore the accretion history and gravitational potential of an otherwise unremarkable late-type galaxy. Given the depth of the LIGHTS images, this system is an example of the types of stellar stream that could be found in a majority of nearby giant galaxies with the 10-year stack of Rubin/LSST data.

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arXiv2026

Downsizing does not extend to dwarf galaxies: identifying the stellar mass regimes shaped by supernova and AGN feedback

We explore how the fraction of red (quenched) galaxies varies in the dwarf galaxy regime (10^7 MSun < Mstar < 10^9.5 MSun), using a mass-complete sample of ~5900 dwarfs at z<0.15, constructed using deep multi-wavelength data in the COSMOS field. The red fraction decreases steadily until Mstar ~ 10^8.5 MSun and then increases again towards lower stellar masses. This 'U' shape demonstrates that the traditional notion of 'downsizing' (i.e. that progressively lower mass galaxies maintain star formation until later epochs) is incorrect -- downsizing does not continue uninterrupted into the dwarf regime. The U shape persists regardless of environment, indicating that it is driven by internal processes rather than external environment-driven mechanisms. Our results suggest that, at Mstar < 10^8 MSun, the quenching of star formation is dominated by supernova (SN) feedback and becomes more effective with decreasing stellar mass, as the potential well becomes shallower. At Mstar > 10^9 MSun, the quenching is driven by a mix of SN feedback and AGN feedback (which becomes more effective with increasing stellar mass, as central black holes become more massive). The processes that quench star formation are least effective in the range 10^8 MSun < Mstar < 10^9 MSun, likely because the potential well is deep enough to weaken the impact of SN feedback, while the effect of AGN feedback is still insignificant. The cosmological simulations tested here do not match the details of how the red fraction varies as a function of stellar mass -- we propose that the red fraction vs stellar mass relation (particularly in the dwarf regime) is a powerful calibrator for the processes that regulate star formation in galaxy formation models.

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arXiv2025

Unlocking the physics of dwarf galaxies in the 2040s: The case for a next-generation wide-field spectroscopic facility with fibres and IFUs

Dwarf galaxies ($M_{\star} \lesssim 10^{9} M_{\odot}$) are the most numerous galaxies in the Universe and critical probes of dark matter, baryonic feedback, and galaxy formation. Despite significant progress from wide-field imaging surveys, the majority of dwarf candidates beyond the Local Group will lack spectroscopic follow-up, leaving fundamental questions about their internal kinematics, stellar populations, chemical enrichment, and dark matter content unresolved. Existing and planned facilities cannot efficiently provide the necessary spectroscopy for low-surface-brightness dwarfs over wide areas. We advocate for a dedicated large-aperture ($\geq 20$ m), wide-field, highly multiplexed spectroscopic facility with deployable or monolithic IFUs, capable of high signal-to-noise observations down to $I_{\rm E} \gtrsim 22-23$ mag. Such a facility would enable transformative studies of dark matter cores, baryonic feedback, tidal interactions, environmental effects, and stellar populations, extending the spectroscopic exploration of low-mass galaxies to $z \sim 1.5$, and providing decisive tests of $\Lambda$CDM and alternative dark matter models. Beyond dwarfs, this capability would impact galaxy evolution, strong and weak lensing studies, and cosmology, ensuring that imaging data from the 2030s and 2040s can be fully exploited.

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arXiv2025

On the Origin of Intracluster Light based on the High-resolution Simulation, NewCluster

Intracluster light (ICL) is a key component of galaxy clusters, with the potential to trace their dynamical assembly histories and the underlying dark matter distribution. Despite these prospects, its faint nature makes a consensus on its origin or population properties difficult to achieve, both in observations and simulations. In the hope of finding a breakthrough, we utilize the ongoing high-resolution cluster simulation, NewCluster. By classifying billions of particles in and around the cluster with a rigorous tracking procedure, we find that the majority of the ICL originates from satellites, including surviving and disrupted galaxies. Another notable finding is that the preprocessed component follows the density profile of dark matter better than the other components and has distinctive properties: old age, low metallicity, and enhanced $\alpha$-element abundance. We further investigate the orbital dynamics, and our results demonstrate that the stripped fraction of satellites is primarily determined by the time since infall and the pericenter distance. By linking the demographic, chemical, and orbital properties of ICL stars to their origins, this work proposes a quantitative approach for tracing the assembly history of galaxy clusters from the ICL.

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arXiv2025

statmorph-lsst: Quantifying and correcting morphological biases in galaxy surveys

Quantitative morphology provides a key probe of galaxy evolution across cosmic time and environments. However, these metrics can be biased by changes in imaging quality - resolution and depth - either across the survey area or the sample. To prepare for the upcoming Rubin LSST data, we investigate this bias for all metrics measured by statmorph and single-component S\'ersic fitting with Galfit. We find that geometrical measurements (ellipticity, axis ratio, Petrosian radius, and effective radius) are robust within 10% at most depths and resolutions. Light concentration measurements ($C$, Gini, $M_{20}$) systematically decrease with resolution, leading low-mass or high-redshift bulge-dominated sources to appear indistinguishable from disks. S\'ersic index $n$, while unbiased, suffers from a 20-40% uncertainty due to degeneracies in the S\'ersic fit. Disturbance measurements ($A$, $A_S$, $D$) depend on signal-to-noise and are thus affected by noise and surface-brightness dimming. We quantify this dependence for each parameter, offer empirical correction functions, and show that the evolution in $C$ observed in JWST galaxies can be explained purely by observational biases. We propose two new measurements - isophotal asymmetry $A_X$ and substructure $St$ - that aim to resolve some of these biases. Finally, we provide a Python package statmorph-lsst implementing these changes and a full dataset that enables tests of custom functions (see text for links).

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arXiv2025

Investigating the imprints of tidal features on simulated galaxy outskirts in LSST-like mock observations

Tidal features provide signatures of recent galaxy mergers, offering insights into the role of mergers in galaxy evolution. The Vera C. Rubin Observatory's upcoming Legacy Survey of Space and Time (LSST) will allow for an unprecedented study of tidal features around millions of galaxies. We use mock images of galaxies at $z\sim0$ ($z\sim0.2$ for \textsc{NewHorizon}) from \textsc{NewHorizon}, \textsc{eagle}, \textsc{IllustrisTNG}, and \textsc{Magneticum Pathfinder} simulations to predict the properties of tidal features in LSST-like images. We find that tidal features are more prevalent around blue galaxies with intrinsic colours $(g-i)\leq0.5$, compared to redder ones, at fixed stellar mass. This trend correlates with elevated specific star formation rates ($\mathrm{sSFR}>10^{-10}\mathrm{\:yr}^{-1}$), suggesting that merger-induced star formation contributes to the bluer colours. Tidal feature hosts in the red sequence appear to exhibit colour profiles offset to bluer colours for galaxies with stellar masses $10^{10}<M_{\star\mathrm{,\:30\:pkpc}}/\mathrm{M}_\odot<10^{11}$, similarly blue cloud tidal feature host galaxies appear to have their colour profiles offset to bluer colours for $10^{9.5}<M_{\star\mathrm{,\:30\:pkpc}}/\mathrm{M}_\odot<10^{10.5}$. However, the differences in colour profiles in either the red sequence or the blue cloud are not statistically robust and larger samples are needed to test if these differences are real. The predictions across the simulations are quantitatively distinct; therefore, LSST observations will allow us to further constrain the differences between different subgrid physics models.

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arXiv2025

The dwarf stellar mass function in different environments and the lack of a generic missing dwarfs problem in {\Lambda}CDM

We combine deep photometric data in the COSMOS and XMM-LSS fields with high-resolution cosmological hydrodynamical simulations to explore two key questions: (1) how does the galaxy stellar mass function, particularly in the dwarf (Mstar < 10^9.5 MSun ) regime, vary with environment, defined as distance from the large-scale structure (LSS) traced by nodes and filaments in the cosmic web? (2) is there a generic 'missing dwarfs' problem in LambdaCDM predictions when all environments - and not just satellites around Milky Way like galaxies - are considered? The depth of the observational data used here enables us to construct complete, unbiased samples of galaxies, down to Mstar ~ 10^7 MSun and out to z ~ 0.4. Strong environmental differences are found for the galaxy stellar mass function when considering distance from LSS. As we move closer to LSS, the dwarf mass function becomes progressively flatter and the knee of the mass function shifts to larger stellar masses, both of which result in a higher ratio of massive to dwarf galaxies. While the stellar mass functions from the three simulations (NewHorizon, TNG50 and FIREbox) considered here do not completely agree across the dwarf regime, there is no evidence of a generic missing dwarfs problem in the context of LambdaCDM, akin to the results of recent work that demonstrates that there is no missing satellites problem around Galactic analogues.

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arXiv2025

Tidal features around simulated groups and cluster galaxies: Enhancement and suppression of merger events through environment in LSST-like mock observations

Generally, merger likelihood increases in denser environments; however, the large relative velocities at the centres of dense clusters are expected to reduce the likelihood of mergers for satellite galaxies. Tidal features probe the recent merger histories of galaxies. The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will produce an unprecedented sample of tidal features around millions of galaxies. We use LSST-like mock observations of galaxies at $z\sim0$ from the EAGLE, IllustrisTNG and Magneticum Pathfinder cosmological-hydrodynamical simulations to predict the occurrence rates of tidal features around satellite galaxies across group and cluster environments in the velocity-radius projected phase-space diagram to investigate the impact of these environments on tidal feature occurrence. We find that ancient infallers in the projected phase-space exhibit a decreasing tidal feature fraction with increasing halo mass, whereas recent infallers in the projected phase-space show unchanging tidal feature fractions with halo mass. Our results show, for the first time in cosmological simulations, a suppression of tidal feature fractions in the central regions of galaxy clusters, indicating a reduced merger rate due to higher cluster-centric velocities and lower galaxy total masses in the cluster centres. Using a toy model, we show that the presence of more tidal features in the recent infaller zone and cluster outskirts suggests that tidal features occur in interactions within infalling groups and dissipate by the time they are ancient infallers, indicating a $\lesssim3\pm2$ Gyr survival time of tidal features within clusters.

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arXiv2025

LIGHTS. A robust technique to identify galaxy edges

The LIGHTS survey is imaging galaxies at a depth and spatial resolution comparable to what the Legacy Survey of Space and Time (LSST) will produce in 10 years (i.e., $\sim$31 mag/arcsec$^2$; 3$\sigma$ in areas equivalent to 10$^{\prime\prime}$$\times$ 10$^{\prime\prime}$). This opens up the possibility of probing the edge of galaxies, as the farthest location of in-situ star formation, with a precision that we have been unable to achieve in the past. Traditionally, galaxy edges have been analyzed in one-dimension through ellipse averaging or visual inspection. Our approach allows for a two-dimensional exploration of galaxy edges, which is crucial for understanding deviations from disc symmetry and the environmental effects on galaxy growth. In this paper, we propose a novel method using the second derivative of the surface mass density map of a galaxy to determine its edges. This offers a robust quantitative alternative to traditional edge-detection methods when deep imaging is available. Our technique incorporates Wiener-Hunt deconvolution to remove the effect of the Point Spread Function (PSF) by the galaxy itself. By applying our methodology to the LIGHTS galaxy NGC 3486, we identify the edge at 205$^{\prime\prime}$ $\pm$ 5$^{\prime\prime}$. At this radius, the stellar surface mass density is $\sim$1 M$_\odot$/pc$^2$, supporting a potential connection between galaxy edges and a threshold for in-situ star formation. Our two-dimensional analysis on NGC 3486 reveals an edge asymmetry of $\sim$5$\%$. These techniques will be of paramount importance for a physically motivated determination of the sizes of galaxies in ultra-deep surveys such as LSST, Euclid and Roman.

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arXiv2025

Morphological Feature Distances Among the Spectral Types of SDSS Galaxies

This study investigates the morphological feature distances among various spectral types of galaxies from the Sloan Digital Sky Survey, including strong and weak active galactic nuclei (AGN), quasi-stellar objects (QSO), quiescent, and star-forming galaxies. We evaluated the clustering and relative distances of these spectral types in the multidimensional morphological feature space. The results indicate that AGN and QSOs are more closely associated with quiescent galaxies than with star-forming ones, indicating a potential regulation of star formation by AGN activity. Furthermore, the analysis underlines the role of AGN feedback in the dwarf regime having $\sim$10%-50% closer distances from AGN types to the quiescent type than to the star-forming type in the dwarf regime $-18 > M_r > -20$, compared to $<$15% closer in the massive regime $M_r < -21$. The continuous probability analysis of spectral types being Hubble types upholds the distance analysis results having a range of the probability distribution of AGN types similar to the quiescent type, especially in dwarf galaxies.

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arXiv2025

Intra-Cluster Light as a Dynamical Clock for Galaxy Clusters: Insights from the MAGNETICUM, IllustrisTNG, Hydrangea and Horizon-AGN Simulations

As the most massive nodes of the cosmic web, galaxy clusters represent the best probes of structure formation. Over time, they grow by accreting and disrupting satellite galaxies, adding those stars to the brightest cluster galaxy (BCG) and the intra-cluster light (ICL). However, the formation pathways of different galaxy clusters can vary significantly. To inform upcoming large surveys, we aim to identify observables that can distinguish galaxy cluster formation pathways. Using four different hydrodynamical simulations, Magneticum, TNG100 of IllustrisTNG, Horizon-AGN, and Hydrangea, we study how the fraction of stellar mass in the BCG and ICL ($f_{ICL+BCG}$) relates to the galaxy cluster mass assembly history. For all simulations, $f_{ICL+BCG}$ is the best tracer for the time at which the cluster has accumulated 50% of its mass ($z_{f}$), performing better than other typical dynamical tracers, such as the subhalo mass fraction, the halo mass, and the center shift. More relaxed clusters have higher $f_{ICL+BCG}$, in rare cases up to 90%, while dynamically active clusters have lower fractions, down to 20%, which we find to be independent of the exact implemented baryonic physics. We determine the average increase in $f_{ICL+BCG}$ from stripping and mergers to be between 3-4% per Gyr. $f_{ICL+BCG}$ is tightly traced by the stellar mass ratio between the BCG and both the second (M12) and fourth (M14) most massive cluster galaxy. The average galaxy cluster has assembled half of its halo mass by $z_{f}=0.67$ (about 6 Gyr ago), though individual histories vary significantly from $z_{f}=0.06$ to $z_{f}=1.77$ (0.8 to 10 Gyr ago). As all four cosmological simulations consistently find that $f_{ICL+BCG}$ is an excellent tracer of the cluster dynamical state, upcoming surveys can leverage measurements of $f_{ICL+BCG}$ to statistically quantify the assembly of the most massive structures.

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arXiv2025

UV LIGHTS. New tools for revealing the low surface brightness regime in the ultraviolet

Ultra-deep optical surveys have reached unprecedented depths, facilitating the study of faint galactic structures. However, the ultraviolet bands, crucial for stellar population studies, remain essentially unexplored at these depths. We present a detailed surface brightness and color analysis of 20 nearby galaxies in the LIGHTS fields observed by GALEX in the FUV and NUV. We adapt and apply a low surface brightness oriented methodology that has proven effective in ultra-deep optical surveys. A novel approach to background subtraction is proposed for UV imaging. Instead of subtracting a constant value from the background, we subtract a Poisson distribution that transforms the background into a pseudo-Gaussian distribution centered at zero. Furthermore, the PSF deconvolution algorithms developed for optical data are applied to our sample, using a novel set of very extended (R=750 arcsec) PSFs for the GALEX bands. This methodology allows us to obtain depths ranging from 28.5 to 30 mag arcsec^{-2}, with reliable surface brightness profiles up to 31 mag arcsec^{-2}. This is about 1 mag deeper than with standard UV techniques. We use the surface brightness and color profiles to show that the application of PSF deconvolution, especially in the FUV, effectively mitigates the excess of light present in the outer regions of certain galaxies compared to the standard GALEX pipeline. This finding is crucial for any accurate stellar population inference from the color profiles. Additionally, a qualitative analysis of the results is presented, with particular emphasis on surface brightness and color properties of the galaxies beyond their optical edges. Our work highlights the importance of developing innovative low surface brightness methods for UV surveys.

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arXiv2025

2D light distributions of dwarf galaxies -- key tests of the implementation of physical processes in simulations

Cosmological simulations provide much of the theoretical framework within which we interpret extragalactic observations. However, even if a given simulation reproduces the integrated properties of galaxies well, it may not reproduce the detailed structures of individual galaxies. Comparisons between the 2D light distributions of simulated and observed galaxies -- particularly in the dwarf regime, where key processes like tidal perturbations and baryonic feedback most strongly influence galaxy structure -- thus provide an additional valuable test of the simulation's efficacy. We compare scaling relations derived from mock observations of simulated galaxies, drawn from the two largest halos in the high-resolution NewHorizon cosmological simulation, with galaxies in the Fornax cluster. While Fornax is significantly more massive than either group, it is the lowest-mass cluster in the local Universe, and contains a well-studied population of spatially resolved dwarfs, hence serves as a useful benchmark. Per unit stellar mass, NewHorizon dwarfs are systematically larger in half-light radius, much fainter in surface brightness, and bluer in colour than their Fornax counterparts, albeit with similar light profile shapes. We discuss potential reasons for these discrepancies, including environmental effects, baryonic feedback, resolution, or couplings of these factors. As observations of dwarfs outside of the local Universe become more plentiful through on-going or up-coming surveys such as Euclid and LSST, 2D comparisons such as these, where properties are measured in the same way across both simulations and observations, can place strong constraints on processes that alter the spatial distribution of baryons in galaxies.

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arXiv2024

LIGHTS. The extended point spread functions of the LIGHTS survey at the LBT

With the arrival of the next generation of ultra-deep optical imaging surveys reaching $\mu_V$$\sim$30 mag/arcsec$^2$ (3$\sigma$; 10"$\times$10"), the removal of scattered light due to the point spread function (PSF) effect remains a critical step for the scientific exploitation of the low surface brightness information contained in these data. Because virtually all pixels in the ground-based images are affected by an unwanted screen of light with a brightness greater than $\mu_V$$\sim$29 mag/arcsec$^2$, the characterization of the extended PSF (R$>$5 arcmin) is mandatory. We describe the procedure used to construct the extended PSFs of the LIGHTS survey in the g- and r-band images taken with the Large Binocular Cameras (LBCs) of the Large Binocular Telescope (LBT). We produce PSFs with a radial extension of 6.5 arcmins. These are later extended to 30 arcmins following an empirically motivated power-law extrapolation of their behaviour in their outermost regions. As an example of the application of our methodology, we subtract the scattered light around the galaxy NGC3198. The result of this subtraction clearly shows the outermost parts of the galaxy's disc, which have been obscured by the influence of nearby bright stars. We make all the PSF (compact and extended) models publicly available.

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arXiv2024

UVCANDELS: Catalogs of photometric redshifts and galaxy physical properties

The UltraViolet imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) program provides deep HST F275W and F435W imaging over four CANDELS fields (GOODS-N, GOODS-S, COSMOS, and EGS). We combine this newly acquired UV imaging with existing HST imaging from CANDELS as well as existing ancillary data to obtain robust photometric redshifts and reliable estimates for galaxy physical properties for over 150,000 galaxies in the $\sim$430 arcmin$^2$ UVCANDELS area. Here, we leverage the power of the new UV photometry to not only improve the photometric redshift measurements in these fields, but also constrain the full redshift probability distribution combining multiple redshift fitting tools. Furthermore, using the full UV-to-IR photometric dataset, we measure the galaxy physical properties by fitting templates from population synthesis models with two different parameterizations (flexible and fixed-form) of the star-formation histories (SFHs). Compared to the flexible SFH parametrization, we find that the fixed-form SFHs systematically underestimate the galaxy stellar masses, both at the low- ($\lesssim10^9 M_\odot$) and high- ($\gtrsim10^{10} M_\odot$) mass end, by as much as $\sim0.5$ dex. This underestimation is primarily due the limited ability of fixed-form SFH parameterization to simultaneously capture the chaotic nature of star-formation in these galaxies.

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