arXiv subjects

M. Radovich

Publications and source records attributed to M. Radovich.

At least 19 recordsLinked to original sources

arXiv2026

Euclid: Quick Data Release (Q1) -- LensMC shear measurement catalogue for cluster lensing science

We present a LensMC lensing analysis of Euclid Quick Release 1 images that were made available in March 2025. We measured shapes, positions, weights, and other morphological parameters of galaxies with a surface number density of $26\;\text{arcmin}^{-2}$ for $I_{\scriptscriptstyle\rm E}<24.5$, achieving 75 arcmin$^{-2}$ for $I_{\scriptscriptstyle\rm E}<27$, in 63 deg$^2$ of Euclid VIS images. This is the first shear measurement catalogue produced with \lensmc in anticipation of the Euclid Data Release 1. To within the scope of this work and availability of survey volume, we found no spatial dependency in the additive biases. However, we developed an empirical bias correction based jointly on galaxy sizes and magnitudes, which was applied to the measurement of the lensing signal over the whole area. In order to validate the quality of our measurements, we calculated two-point statistics and cluster profile measurements, and cross-checked results with external cluster catalogues from WISE and the Dark Energy Survey. Additionally, by stacking shear profiles of random clusters we found that the low-redshift, large radii bins may be still contaminated by residual systematic effects. Thanks to Euclid image resolution and depth and overall good control of systematic errors, we are able to constrain the lensing profiles of clusters with masses of $10^{14}M_\odot$ out to $z\approx2$ over nearly 10 Gyr of evolution history.

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arXiv2026

KiDS-Legacy: Joint analysis of second- and third-order cosmic shear

Weak lensing by large-scale structure is a powerful cosmological probe. While most analyses rely on second-order correlations, these are primarily sensitive to the parameter combination $S_8 = \sigma_8 (\Omega_m/0.3)^{0.5}$, limiting their ability to constrain $\Omega_m$ and other cosmological parameters independently. Higher-order statistics capture non-Gaussian features of the density field and can therefore break parameter degeneracies and extract more cosmological information from weak lensing surveys. We present a joint analysis of second- and third-order cosmic shear in the final data release of the Kilo-Degree Survey (KiDS-Legacy). We combine COSEBIs (Complete Orthogonal Sets of E-/B-mode Integrals) at scales between 2' and 300' with third-order aperture mass moments at scales between 4' and 32' to perform a joint analysis of second- and third-order statistics. Compared to previous KiDS analyses, we implement several methodological advances: an intrinsic alignment model with redshift and mass dependence, a baryon correction model validated on multiple hydrodynamical simulations, and corrections for reduced shear and source clustering. Combining COSEBIs with third-order aperture mass statistics in KiDS-Legacy yields $\Omega_m = 0.297^{+0.056}_{-0.040}$ and $S_8 = 0.806^{+0.025}_{-0.023}$, significantly tightening the $\Omega_m$ constraints and more than doubling the figure of merit in the $\Omega_m$--$S_8$ plane compared to the two-point analysis alone. The third-order measurements pass stringent internal consistency tests, are fully compatible with the KiDS-Legacy 2-point constraints, other 2+3-point lensing results and with Planck CMB measurements within $1\sigma$, providing no evidence for an $S_8$ tension and demonstrating the maturity of 3-point cosmic shear as a key probe for forthcoming surveys.

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arXiv2026

Molecular gas and star formation in GASP jellyfish galaxies

Several studies have reported a nearly linear correlation between the molecular gas and star formation rate surface density, the so-called Kennicutt-Schmidt (KS) law. We aim to retrieve the KS relation for a sample of four star-forming galaxies located in nearby clusters, disturbed by the effects of the ram pressure stripping, as testing this law in galaxies subject to different environmental conditions can provide key information on the physics of star formation. To perform our analysis, we used ALMA band 6 and band 3 data coupled with MUSE data at spatial resolution of ~1 kpc. Moreover, we analyzed data of star-forming complexes detected through their H\alpha ionized gas emission. We also derived the star formation efficiencies of the star-forming regions nested in these big complexes using the star formation rates derived from spatially resolved HST images and various recipes for the corresponding cold gas phase. We find that ram-pressure-stripped galaxies show normal-to-low star formation efficiencies, depending on the position within the galaxy and on the local gas density: the inner dense regions in the disk show higher efficiencies with respect to the outer regions, including the gaseous tails. The global relation between the star formation rate density and the molecular gas surface density is superlinear, likely suggesting the shortening of the depletion times at high gas mass densities caused by the ram pressure. Within the star-forming complexes, the star formation efficiency is very similar to the one observed at 1 kpc scale in undisturbed star-forming disks. Interestingly, this result holds also for the star-forming complexes located in the stripped gas tails. The analysis of HST resolved clumps suggests that the molecular gas is not uniformly distributed within the star-forming complexes, but its density distribution follows a steeper profile.

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arXiv2026

AMICO galaxy clusters in KiDS-1000: Splashback radius from weak lensing and cluster-galaxy correlation function

We present the splashback radius analysis of the Adaptive Matched Identifier of Clustered Objects (AMICO) galaxy cluster sample in the fourth data release of the Kilo Degree Survey (KiDS). The sample contains 9049 rich galaxy clusters within $z\in[0.1,0.8]$, with shear measurements available for 8730 of them. We measure and model the stacked reduced shear, $g_{\rm t}$, and the cluster-galaxy correlation function, $w_{\rm cg}$, in bins of observed intrinsic richness, $\lambda^*$, and redshift, $z$. Building on the methods employed in recent cosmological analyses, we model the average splashback radius, $r_{\rm sp}$, of the underlying dark matter halo distribution, accounting for the known systematic uncertainties affecting measurements and theoretical models. By modelling $g_{\rm t}$ and $w_{\rm cg}$ separately, in the cluster-centric radial range $R\in[0.4,5]$ $h^{-1}$Mpc, we constrain $r_{\rm sp}$, the mass accretion rate, $\Gamma$, and the relation between $\mathcal{R}_{\rm sp}\equiv r_{\rm sp}/r_{200\rm m}$ and the peak height, $\nu_{200\rm m}$, over the mass range $M_{200\rm m}\in[0.4,20]$ $10^{14}h^{-1}$M$_\odot$. The two probes provide consistent results that also agree with $\Lambda$-cold dark matter model predictions. Our $\mathcal{R}_{\rm sp}$ constraints are consistent with those from previous observations. For $g_{\rm t}$ and $w_{\rm cg}$, we achieve a precision of 14% and 10% per cluster stack, respectively. The higher precision of $w_{\rm cg}$, enabled by its combination with weak-lensing constraints on the mass-richness relation, highlights the complementarity of lensing and clustering in measuring $r_{\rm sp}$ and constraining the properties of the infalling material region.

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arXiv2025

Gravity-Selected Galaxy Clusters: a Tight Mass-Richness relation and an unclear Compton $Y$-richness trend

This paper, the third in a series, investigates the scaling relations between optical richness, weak-lensing mass, and Compton $Y$ for a sample of galaxy clusters selected purely by the effect of their gravitational potential on the shapes of background galaxies. This selection method is uncommon, as most cluster samples in the literature are selected based on signals originating from cluster baryons. We analize a complete sample of 13 gravity-selected clusters at intermediate redshifts (with $0.12 \leq z_{phot} \leq 0.40$) with weak-lensing signal-to-noise ratios exceeding 7. We measured cluster richness by counting red-sequence galaxies, identifying two cases of line-of-sight projections in the process, later confirmed by spectroscopic data. Both clusters are sufficiently separated in redshift that contamination in richness can be straighforwardly dealt because the two red sequences do not blend each other. We find an exceptionally tight richness--mass relation using our red-sequence-based richness estimator, with a scatter of just $\sim0.05$ dex, smaller than the intrinsic scatter of Compton Y with mass for the same sample. The lower scatter highlights the effectiveness of richness compared to Compton $Y$. No outliers are found in the richness-mass scaling, whether or not one cluster with a mass likely affected by projection effects is included in the sample. In the Compton $Y$-richness plane, the data do not delineate a clear trend. The limited sample size is not the sole reason for the unclear relation between Compton $Y$ and richness, since the same sample, with identical richness values, exhibits a highly significant and tight mass-richness correlation.

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arXiv2025

Euclid preparation. XCI. Validation method for the detections in the Euclid Catalogue of Galaxy Clusters using external data

We present our methodology for identifying known clusters as counterparts to objects in the Euclid Catalogue of Galaxy Clusters (ECGC). Euclid is expected to detect a large number of optically-selected galaxy clusters over the approximately 14000 square degrees of its extragalactic sky survey. Extending out well beyond redshift unity, the catalogue will contain many new high-redshift clusters, while at lower redshifts a fraction of the clusters will have been observed in other surveys. Identifying these known clusters as counterparts to the Euclid-detected clusters is an important step in the validation and construction of the ECGC to augment information with external observables. We present a set of catalogues and meta-catalogues of known clusters that we have assembled for this step, and we illustrate their application and our methodology using the Dark Energy Survey Year 1 RedMaPPer cluster catalogue in lieu of the future ECGC. In the process of this work, we have constructed and delivered an updated EC-RedMaPPer catalogue with multi-wavelength counterparts.

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arXiv2025

AMICO galaxy clusters in KiDS-1000: cosmological sample

Context. Galaxy clusters provide key insights into cosmic structure formation, galaxy formation and are essential for cosmological studies. Aims. We present a catalog of galaxy clusters detected in the Kilo-Degree Survey (KiDS-DR4) optimized for cosmological analyses and investigations of cluster properties. Each detection includes probabilistic membership assignments for the KiDS-DR4 galaxies within the magnitude range $15 3.5$. The sample is highly homogeneous across the entire survey thanks to the restrictive galaxy selection criteria we adopted. Spectroscopic data from the GAMA survey were used to calibrate the clusters photometric redshift and assess their uncertainties. We introduced algorithmic enhancements to AMICO to mitigate border effects among neighbor tiles. Quality flags are also provided for each cluster detection. The sample purity and completeness assessments have been estimated using the SinFoniA data driven approach, thus avoiding strong assumptions embedded in numerical simulations. We introduced a blinding scheme of the selection function meant to support the cosmological analyses. Results. Our cluster sample includes 321 cross-matches with the X-ray eRASS1 "primary" sample and 235 matches with the ACT-DR5 cluster sample. We derived a mass-proxy scaling relation based on intrinsic richness, $\lambda_*$, using masses from the eRASS1 catalog. Conclusions. The KiDS-DR4 cluster catalog provides a valuable data set for investigating galaxy cluster properties and contributes to cosmological studies by offering a large, well-characterized cluster sample.

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arXiv2025

AMICO galaxy clusters in KiDS-1000: cosmological constraints and mass calibration from counts and weak lensing

We present the joint modelling of weak-lensing and count measurements of the galaxy clusters detected with the AMICO code, in the fourth data release of the Kilo Degree Survey (KiDS-1000). The analysed sample comprises about 8000 clusters, covering an effective area of 839 deg$^{2}$ and extending up to a redshift of $z = 0.8$. Stacked cluster weak-lensing and count measurements have been derived in bins of redshift and intrinsic richness, $\lambda^*$. Based on self-organising maps, we reconstructed the true redshift distributions of the background galaxy samples. We accounted for the systematic uncertainties arising from impurities in the background and cluster samples, biases in the cluster $z$ and $\lambda^*$, projection effects, halo orientation and miscentring, truncation of cluster halo mass distributions, matter correlated with cluster haloes, multiplicative shear bias, baryonic matter, geometric distortions in the lensing profiles, uncertainties in the theoretical halo mass function, and super-sample covariance. We also employed a blinding strategy based on perturbing the cluster sample completeness. The improved statistics and photometry compared to the previous KiDS data release, KiDS-DR3, have led to a halving of the uncertainties on $\Omega_{\rm m}$ and $\sigma_8$, as we obtained $\Omega_{\rm m}=0.22\pm0.02$ and $\sigma_8=0.86\pm0.03$. The constraint on $S_8 \equiv \sigma_8(\Omega_{\rm m}/0.3)^{0.5}$, $S_8=0.74\pm0.03$, is in excellent agreement with recent cluster count and KiDS-1000 cosmic shear analyses, while it shows a $2.8\sigma$ tension with Planck cosmic microwave background results. The constraints on the $\log\lambda^*-\log M_{200}$ relation imply a mass precision of 8%, on average. In addition, the result on the intrinsic scatter of the $\log\lambda^*-\log M_{200}$ relation, $\sigma_{\rm intr}=0.05\pm0.02$, confirms that $\lambda^*$ is an excellent mass proxy.

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arXiv2025

Gravity-selected cluster samples: a new take on the Compton Y-mass relation

We investigate the scaling relation between the Compton Y parameter and mass in a gravity-selected sample of galaxy clusters, selected based on their gravitational lensing effects on background galaxies. Unlike ICM-selected samples, gravity-selected clusters do not require corrections for selection biases in intracluster medium (ICM) properties, such as Compton Y, since these properties are not used for selection. Our sample consists of 13 gravity-selected clusters with weak-lensing signal-to-noise ratios greater than 7 and redshifts in the range $0.1 < z < 0.4$, drawn from the peak catalog of shear-selected clusters in Oguri et al. (2021). We determined spectroscopic redshifts using SDSS spectroscopy, derived tangential radial profiles from HSC shear data, and calculated cluster masses by fitting a Navarro, Frenk, \& White (1997) profile. Compton Y measurements were obtained from ACT maps. Our sample reveals a broader scatter in the Compton Y-mass scaling relation compared to ICM-selected samples, even after accounting for selection effects and mass bias of the latter, that we find to be $(1-b) = 0.72 \pm 0.09$. Additionally, we identify a second population of clusters with unusually small Compton Y for their mass, which is absent in ICM-selected samples. This second population comprises $13^{+10}_{-8}$\% of the entire sample, with O19 currently being the only secure representative.

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arXiv2025

A new quasar strongly-lensed candidate by the galaxy cluster WHJ0400-27 with a $18''$ image-separation

Time-delay cosmography (TDC) using multiply-lensed quasars (QSOs) by galaxies has recently emerged as an independent and competitive tool to measure the value of the Hubble constant. Lens galaxy clusters hosting multiply-imaged QSOs, when coupled with an accurate and precise knowledge of their total mass distribution, are equally powerful cosmological probes. However, less than ten such systems have been identified to date. Our study aims to expand the limited sample of cluster-lensed QSO systems by identifying new candidates within rich galaxy clusters. Starting from a sample of ~$10^5$ galaxy cluster candidates (Wen & Han, 2022), built from Dark Energy Survey and Wide-field Infrared Survey Explorer imaging data, and a highly-pure catalogue of over one million QSOs, based on Gaia DR3 data, we cross-correlate them to identify candidate lensed QSOs near the core of massive galaxy clusters. Our search yielded 3 lensed double candidates over an area of ~$5000$ sq. degree. In this work, we focus on the best candidate consisting of a double QSO with Gaia-based redshift of 1.35, projected behind a moderately rich cluster (WHJ0400-27) at $z_{phot}=0.65$. Based on a first spectroscopic follow-up study, we confirm the two QSOs at $z=1.345$, with indistinguishable spectra, and a brightest cluster galaxy at $z=0.626$. These observations seem to support the strong lensing nature of this system, although some tension emerges when the cluster mass from a preliminary lens model is compared with that from other mass proxies. We also discuss the possibility that such system is a rare physical association of two distinct QSOs with a projected physical distance of ~$150$ kpc. If further spectroscopic observations confirm its lensing nature, such a rare lens system would exhibit one of the largest image separations observed to date ($\Delta\vartheta=17.8''$), opening interesting TDC applications.

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arXiv2025

CHEX-MATE: Multi-probe analysis of Abell 1689

The nature of the elusive dark matter can be probed by comparing the predictions of the cold dark matter framework with the gravitational field of massive galaxy clusters. However, a robust test of dark matter can only be achieved if the systematic uncertainties in the reconstruction of the gravitational potential are minimized. Techniques based on the properties of intracluster gas rely on the assumption that the gas is in hydrostatic equilibrium within the potential well, whereas gravitational lensing is sensitive to projection effects. Here we attempt to minimize systematics in galaxy cluster mass reconstructions by jointly exploiting the weak gravitational lensing signal and the properties of the hot intracluster gas determined from X-ray and millimeter (Sunyaev-Zel'dovich) observations. We construct a model to fit the multi-probe information within a common framework, accounting for non-thermal pressure support and elongation of the dark matter halo along the line of sight. We then apply our framework to the massive cluster Abell 1689, which features unparalleled multi-wavelength data. In accordance with previous works, we find that the cluster is significantly elongated along the line of sight. Accounting for line-of-sight projections, we require a non-thermal pressure support of $30\text{-}40\%$ at $r_{500}$ to match the gas and weak lensing observables. The joint model retrieves a concentration $c_{200}\sim7$, which is lower and more realistic than the high concentration retrieved from weak lensing data alone under the assumption of spherical symmetry ($c_{200}\sim15$). Application of our method to a larger sample will allow us to study at the same time the shape of dark matter mass profiles and the level of non-thermal pressure support in galaxy clusters.

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arXiv2025

Euclid Quick Data Release (Q1). NIR processing and data products

This paper describes the near-infrared processing function (NIR PF) that processes near-infrared images from the Near-Infrared Spectrometer and Photometer (NISP) instrument onboard the Euclid satellite. NIR PF consists of three main components: (i) a common pre-processing stage for both photometric (NIR) and spectroscopic (SIR) data to remove instrumental effects; (ii) astrometric and photometric calibration of NIR data, along with catalogue extraction; and (iii) resampling and stacking. The necessary calibration products are generated using dedicated pipelines that process observations from both the early performance verification (PV) phase in 2023 and the nominal survey operations. After outlining the pipeline's structure and algorithms, we demonstrate its application to Euclid Q1 images. For Q1, we achieve an astrometric accuracy of 9-15 mas, a relative photometric accuracy of 5 mmag, and an absolute flux calibration limited by the 1% uncertainty of the Hubble Space Telescope (HST) CALSPEC database. We characterise the point-spread function (PSF) that we find very stable across the focal plane, and we discuss current limitations of NIR PF that will be improved upon for future data releases.

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arXiv2025

The uncommon intracluster medium features of the first massive clusters selected independently of their baryon content

Our current knowledge of the thermodynamic properties of galaxy clusters comes primarily from detailed studies of clusters selected by their minority components: hot baryons. Most of these studies select the clusters using the component that is being investigated, the intracluster medium (ICM), making the sample choice prone to selection effects. Weak-gravitational lensing allows us to select clusters by the total mass component and, being independent of the type of matter, makes the sample choice unbiased with respect to the baryon content. In this paper, we study four galaxy clusters at intermediate redshift ($0.25 2\sigma$) features, while we observed on average two rare features in each one of the seven explored properties: richness, core-excised luminosity, Compton parameter, pressure and electron pressure profiles, and central values of them. The abundance of rare and unique features in such a small sample indicates a fundamental bias in our knowledge of the thermodynamic properties of clusters when derived from ICM-selected samples.

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arXiv2024

Euclid preparation: Determining the weak lensing mass accuracy and precision for galaxy clusters

We investigate the level of accuracy and precision of cluster weak-lensing (WL) masses measured with the \Euclid data processing pipeline. We use the DEMNUni-Cov $N$-body simulations to assess how well the WL mass probes the true halo mass, and, then, how well WL masses can be recovered in the presence of measurement uncertainties. We consider different halo mass density models, priors, and mass point estimates. WL mass differs from true mass due to, e.g., the intrinsic ellipticity of sources, correlated or uncorrelated matter and large-scale structure, halo triaxiality and orientation, and merging or irregular morphology. In an ideal scenario without observational or measurement errors, the maximum likelihood estimator is the most accurate, with WL masses biased low by $\langle b_M \rangle = -14.6 \pm 1.7 \, \%$ on average over the full range $M_\text{200c} > 5 \times 10^{13} \, M_\odot$ and $z < 1$. Due to the stabilising effect of the prior, the biweight, mean, and median estimates are more precise. The scatter decreases with increasing mass and informative priors significantly reduce the scatter. Halo mass density profiles with a truncation provide better fits to the lensing signal, while the accuracy and precision are not significantly affected. We further investigate the impact of additional sources of systematic uncertainty on the WL mass, namely the impact of photometric redshift uncertainties and source selection, the expected performance of \Euclid cluster detection algorithms, and the presence of masks. Taken in isolation, we find that the largest effect is induced by non-conservative source selection. This effect can be mostly removed with a robust selection. As a final \Euclid-like test, we combine systematic effects in a realistic observational setting and find results similar to the ideal case, $\langle b_M \rangle = - 15.5 \pm 2.4 \, \%$, under a robust selection.

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arXiv2024

Euclid preparation. XLIX. Selecting active galactic nuclei using observed colours

Euclid will cover over 14000 $deg^{2}$ with two optical and near-infrared spectro-photometric instruments, and is expected to detect around ten million active galactic nuclei (AGN). This unique data set will make a considerable impact on our understanding of galaxy evolution and AGN. In this work we identify the best colour selection criteria for AGN, based only on Euclid photometry or including ancillary photometric observations, such as the data that will be available with the Rubin legacy survey of space and time (LSST) and observations already available from Spitzer/IRAC. The analysis is performed for unobscured AGN, obscured AGN, and composite (AGN and star-forming) objects. We make use of the spectro-photometric realisations of infrared-selected targets at all-z (SPRITZ) to create mock catalogues mimicking both the Euclid Wide Survey (EWS) and the Euclid Deep Survey (EDS). Using these catalogues we estimate the best colour selection, maximising the harmonic mean (F1) of completeness and purity. The selection of unobscured AGN in both Euclid surveys is possible with Euclid photometry alone with F1=0.22-0.23, which can increase to F1=0.43-0.38 if we limit at z>0.7. Such selection is improved once the Rubin/LSST filters (a combination of the u, g, r, or z filters) are considered, reaching F1=0.84 and 0.86 for the EDS and EWS, respectively. The combination of a Euclid colour with the [3.6]-[4.5] colour, which is possible only in the EDS, results in an F1-score of 0.59, improving the results using only Euclid filters, but worse than the selection combining Euclid and LSST. The selection of composite ($f_{{\rm AGN}}$=0.05-0.65 at 8-40 $\mu m$) and obscured AGN is challenging, with F1<0.3 even when including ancillary data. This is driven by the similarities between the broad-band spectral energy distribution of these AGN and star-forming galaxies in the wavelength range 0.3-5 $\mu m$.

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arXiv2023

Euclid Preparation. XXXVII. Galaxy colour selections with Euclid and ground photometry for cluster weak-lensing analyses

We derived galaxy colour selections from Euclid and ground-based photometry, aiming to accurately define background galaxy samples in cluster weak-lensing analyses. Given any set of photometric bands, we developed a method for the calibration of optimal galaxy colour selections that maximises the selection completeness, given a threshold on purity. We calibrated galaxy selections using simulated ground-based $griz$ and Euclid $Y_{\rm E}J_{\rm E}H_{\rm E}$ photometry. Both selections produce a purity higher than 97%. The $griz$ selection completeness ranges from 30% to 84% in the lens redshift range $z_{\rm l}\in[0.2,0.8]$. With the full $grizY_{\rm E}J_{\rm E}H_{\rm E}$ selection, the completeness improves by up to $25$ percentage points, and the $z_{\rm l}$ range extends up to $z_{\rm l}=1.5$. The calibrated colour selections are stable to changes in the sample limiting magnitudes and redshift, and the selection based on $griz$ bands provides excellent results on real external datasets. The $griz$ selection is also purer at high redshift and more complete at low redshift compared to colour selections found in the literature. We find excellent agreement in terms of purity and completeness between the analysis of an independent, simulated Euclid galaxy catalogue and our calibration sample, except for galaxies at high redshifts, for which we obtain up to 50 percent points higher completeness. The combination of colour and photo-$z$ selections applied to simulated Euclid data yields up to 95% completeness, while the purity decreases down to 92% at high $z_{\rm l}$. We show that the calibrated colour selections provide robust results even when observations from a single band are missing from the ground-based data. Finally, we show that colour selections do not disrupt the shear calibration for stage III surveys.

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arXiv2023

AMICO galaxy clusters in KiDS-DR3: Cosmological constraints from angular power spectrum and correlation function

We study the tomographic clustering properties of the photometric cluster catalogue derived from the Third Data Release of the Kilo Degree Survey, focusing on the angular correlation function and its spherical harmonic counterpart, the angular power spectrum. We measure the angular correlation function and power spectrum from a sample of 5162 clusters, with an intrinsic richness $\lambda^*\geq 15$, in the photometric redshift range $z\in [0.1, 0.6]$, comparing our measurements with theoretical models, in the framework of the $\Lambda$-Cold Dark Matter cosmology. We perform a Monte Carlo Markov Chain analysis to constrain the cosmological parameters $\Omega_{\mathrm{m}}$, $\sigma_8$ and the structure growth parameter $S_8\equiv\sigma_8 \sqrt{\Omega_{\mathrm{m}}/0.3}$. We adopt Gaussian priors on the parameters of the mass-richness relation, based on the posterior distributions derived from a previous joint analysis of cluster counts and weak lensing mass measurements carried out with the same catalogue. From the angular correlation function, we obtain $\Omega_{\mathrm{m}}=0.32^{+0.05}_{-0.04}$, $\sigma_8=0.77^{+0.13}_{-0.09}$ and $S_8=0.80^{+0.08}_{-0.06}$, in agreement, within $1\sigma$, with 3D clustering result based on the same cluster sample and with existing complementary studies on other datasets. For the angular power spectrum, we derive statistically consistent results, in particular $\Omega_{\mathrm{m}}=0.24^{+0.05}_{-0.04}$ and $S_8=0.93^{+0.11}_{-0.12}$, while the constraint on $\sigma_8$ alone is weaker with respect to the one provided by the angular correlation function, $\sigma_8=1.01^{+0.25}_{-0.17}$. Our results show that the 2D clustering from photometric cluster surveys can provide competitive cosmological constraints with respect to the full 3D clustering statistics, and can be successfully applied to ongoing and forthcoming spectro/photometric surveys.

astro-ph.CO↗

arXiv2023

INSPIRE: INvestigating Stellar Population In RElics V. A catalogue of ultra-compact massive galaxies outside the local Universe and their degree of relicness

This paper presents the third data release of the INvestigating Stellar Population In RElics (INSPIRE) project, comprising 52 ultra-compact massive galaxies (UCMGs) observed with the X-Shooter spectrograph. We measure integrated stellar velocity dispersion, [Mg/Fe] abundances, ages, and metallicities for all the INSPIRE objects. We thus infer star formation histories and confirm the existence of a degree of relicness (DoR), defined in terms of the fraction of stellar mass formed by $z=2$, the time at which a galaxy has assembled 75\% of its mass, and the final assembly time. Objects with a high DoR assembled their stellar mass at early epochs, while low-DoR objects show a non-negligible fraction of later-formed populations and hence a spread in ages and metallicities. A higher DoR correlates with larger [Mg/Fe], super-solar metallicity, and larger velocity dispersion values. The 52 UMCGs span a large range of DoR from 0.83 to 0.06, with 38 of them having formed more than 75\% of their mass by $z=2$. Of these, nine are extreme relics (DoR$>0.7$), since they formed the totality ($>99\%$) of their stellar mass by redshift $z=2$. The remaining 14 UCMGs cannot be considered relics, as they are characterised by more extended star formation histories. With INSPIRE, we built the first sizeable sample of relics outside the local Universe, up to $z\sim0.4$, increasing the number of confirmed relics by a factor of $>10$, and opening up an important window to explain the mass assembly of massive galaxies in the high-z Universe.

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