arXiv subjects

Priyamvada Natarajan

Publications and source records attributed to Priyamvada Natarajan.

At least 19 recordsLinked to original sources

arXiv2026

Magnetically Arrested Accretion and Black Hole Spin in a Semi-Analytic Model of Galaxy Formation

We present {\sc Mad Sage}, a semi-analytic model of galaxy formation that couples black hole mass and spin evolution to gas accretion and AGN feedback under magnetically arrested disk conditions. Building on the {\sc Dark Sage} model, we incorporate GRMHD-calibrated prescriptions for spin evolution and jet power, spin-dependent radiative efficiencies, and remnant spins from BH-BH mergers. We compare accretion and feedback models, including coherent disk-fed accretion with mixed coherent and incoherent hot-halo accretion, with and without additional mechanical feedback. We find that incoherent accretion, together with Blandford-Znajek spin-down, drives massive BHs toward low spins, reducing jet efficiencies and weakening the quenching of massive galaxies. Reproducing the high-mass end of the stellar mass function requires either exclusively coherent accretion or an additional feedback component provided by ADAF outflows. Our models broadly reproduce observed BH-galaxy scaling relations, disk surface density profiles, and the AGN luminosity function at $z\sim 2-6$, although the spin models under-predict the number density of faint AGN at low redshift. At $z\lesssim 3$, predicted BH spins decrease with increasing BH mass, while at higher redshifts, the mass dependence weakens. Spin distributions peak at $|a_\star|\sim 0.5$-$0.7$, below current X-ray reflection spectroscopy measurements, and become bimodal for massive, quiescent BHs accessible with the next generation Event Horizon Telescope and the Black Hole EXplorer. We report that the predicted LISA event rates are nearly independent of the adopted accretion and spin models.

astro-ph.GA↗

arXiv2026

Bridging Scales: Multi-Zone GRMHD-Informed Anisotropic AGN Feedback in Galaxies

We present a galaxy-scale black hole (BH) accretion and feedback model incorporating results from multi-zone general relativistic magnetohydrodynamic (GRMHD) simulations spanning the event horizon to the Bondi radius. The model replaces a fixed suppression of the Bondi rate with a nuclear-environment-dependent factor, $κ^{\rm hot}_{\rm cho}$, set by the local ratio of Bondi to gravitational radius, and distributes outflow mass, kinetic energy, and thermal energy according to the angular structure measured in the large-dynamic-range GRMHD calculations. We apply it to idealized isolated simulations of an M87*-like massive elliptical and a Milky Way/Sgr A*-like galaxy, spanning over three orders of magnitude in BH mass without tuning accretion or feedback efficiencies to match observables. In the M87*-like system, the GRMHD-informed angle-dependent feedback model suppresses late-time stellar mass growth more effectively than the isotropic reference model, despite similar long-term BH accretion rates. Varying the uncertain mass loading of the collimated polar component has a modest impact on BH growth and star formation, indicating that feedback anisotropy matters more than its detailed mass loading. We find that $κ^{\rm hot}_{\rm cho}$ varies with nuclear environment and time, yielding BH growth histories markedly different from fixed-suppression models. For Sgr A*, this variable factor yields an accretion rate more consistent with Event Horizon Telescope (EHT) constraints than a fixed, suppressed Bondi model. These results show that nuclear-environment-dependent accretion and feedback angular structure affect BH-galaxy evolution, requiring subgrid models to include more than a universal Bondi suppression factor and a scalar feedback efficiency.

astro-ph.GA↗

arXiv2026

A GLIMPSE of Dark Matter: JWST Constraints on Early Structure Formation

While we have a solid understanding of how dark matter (DM) behaves during recombination ($z\sim 10^3$) and in the late universe ($z\lesssim$ a few), much less is known about intermediate times, when the first galaxies formed. These galaxies provide a powerful handle on DM through structure formation, as halos have to exist to host luminous sources. Here we use recent determinations of the UV luminosity function from the James Webb Space Telescope (JWST) GLIMPSE lensing program, along with legacy Hubble and Subaru data, to test the small-scale behavior of DM during the epoch of reionization ($z\sim 7$). Marginalizing over astrophysical uncertainties, we find the matter power spectrum to be consistent with the cold-DM prediction down to sub-Mpc scales, with 1$σ$ uncertainties of 0.2 dex at $k=3-9 \, \rm Mpc^{-1}$ and 0.5 dex at $k=9-27 \, \rm Mpc^{-1}$, the smallest scales probed at these early times. For thermal-relic warm DM we constrain $m_{\rm WDM} > 3.2\, \rm keV$ (95% CL), independent of lower-$z$ probes. Our results test small-scale structure formation in a new redshift window and demonstrate the promise of JWST to constrain the nature of DM.

astro-ph.CO↗

arXiv2026

The Connection Between the Growth of Massive Black Holes and Their Dynamical Histories

Massive black holes (MBHs) grow through both gas accretion and mergers and it remains unclear how variations to MBH growth and dynamical histories contribute to the spread in empirical scaling relations between MBHs and their host galaxies. We examine the ex- and in-situ growth of MBHs within large-scale cosmological simulations and compare the evolution of an outlier population of under-grown MBHs to the general population. We use the Romulus25 uniform volume cosmological simulation and the RomulusC cluster zoom-in simulation to examine the growth and merger histories of MBHs. We identify central MBHs that are undergrown relative to other MBHs in similar mass galaxies and investigate their accretion, merger, and orbital histories within the simulations. The contribution of ex-situ growth increases with MBH mass, with mergers becoming increasingly important in the most massive galaxies. We find no difference between cluster and field environments in terms of the importance of ex-situ growth, which is generally very low. Under-grown MBHs have experienced fewer mergers and have had complex dynamical histories, spending significant time 'drifting' within the galaxy or 'competing' with another MBH. Other under-grown MBHs have experienced a 'late entrance' into a galaxy which until then had no central MBH. Our results demonstrate that MBH assembly is dominated by in-situ growth, which in turn is impacted by the dynamical histories of MBHs within assembling galaxies. Prolonged off-centre evolution can suppress accretion and contribute to the formation of under-grown central MBHs at $z=0$.

astro-ph.GA↗

arXiv2026

Where Cluster Galaxies Reside and How Strongly They Lens

The efficiency of galaxy-galaxy strong lensing (GGSL) in clusters depends jointly on the inner mass distributions of member galaxies and their locations within the cluster potential. Observed GGSL probabilities exceed $Λ$CDM predictions by nearly an order of magnitude, but the relative roles of internal structure and environment remain unclear. We disentangle these effects by comparing HST strong-lensing clusters with TNG-Cluster analogs at similar lens redshifts, matched by their primary Einstein radius. For each member, we measure its lensing strength in isolation and when embedded in the cluster field. Members in cluster-critical regions are classified as Major or Minor Perturbers depending on whether they strongly lens in isolation; those in subcritical regions are classified as Intrinsic Lenses, Boosted Lenses, or Inert Members according to whether they lens independently, only with environmental assistance, or not at all. Observed clusters contain 33.7% of selected members in cluster-critical regions, compared with 21.6% in TNG-Cluster, while their Major-to-Minor ratios are similar. Outside these regions, observations contain substantially more Intrinsic and Boosted Lenses and fewer Inert Members, with Boosted Lens fractions of 25.8% and 13.5%, respectively. The discrepancy persists at fixed subhalo mass and after including line-of-sight structure. A mass-conserving contraction mimicking core-collapsed self-interacting dark matter largely recovers the conditional lensing fractions but not cluster-critical occupancy. The GGSL discrepancy therefore reflects both insufficient central concentration in simulated members and differences in their locations within the cluster lensing field.

astro-ph.CO↗

arXiv2026

A Consistent Implementation of Cluster Strong Lensing in Cosmological Simulation Light Cones

Galaxy cluster strong gravitational lensing plays a central role in precision cosmology, yet robust theoretical predictions have lagged behind an abundance of high-quality strong lensing observations. This shortfall reflects both a mismatch between the geometry of the strong-lensing problem and standard cubic simulation boxes, and the fundamental tension between simulation volume and resolution. Consequently, many current forecasts adopt hybrid approaches that extract individual lenses from simulations and combine them with analytic or observed source populations positioned near caustics. These methods often omit correlated and/or uncorrelated line-of-sight (LoS) structure, or include it in ways that do not preserve correlations across redshift. Here we present a fully simulation-based procedure that generates strong-lensing images directly from particle data, drawing the lens, source, and all intervening resolved objects self-consistently from the simulated large-scale structure. Our approach combines a structure-preserving remapping of the simulation volume into a lensing-appropriate geometry with multi-plane ray tracing, enabling the use of uniform simulation boxes that resolve both cluster-scale primary lenses and high-redshift source galaxies. We demonstrate the method by generating example light cones and images using IllustrisTNG data, then use these results to conservatively quantify the impact of LoS structure on image configurations and critical-curve morphology. We find that uncorrelated LoS structure can shift the relative positions of lensed images by several arcseconds, introduces a $\sim 6\%$ scatter in the area of a cluster's primary critical curve, and changes the total critical area within 100$^{\prime\prime}$ of the cluster potential minimum by $16^{+20\%}_{-14\%}$ at a source plane redshift of $z_s=4$.

astro-ph.CO↗

arXiv2026

SLICE: Unveiling the Multi-Component Merging Core of SPT-CLJ1150-2805 Through Strong-Lensing Mass Modelling

We present a new strong-lensing and X-ray mass model of the merging galaxy cluster SPT-CLJ1150-2805 ($z=0.383$), combining JWST NIRCam, HST, Chandra, and VLT/MUSE data to robustly decompose its collisionless and collisional components. Exploiting JWST, we expand the multiple-image catalogue with 66 new images (30 comprising 6 new systems). Our baseline model uses 118 spectroscopically confirmed images from 20 systems, achieving an image-plane root-mean-square offset of $0.56''$. An expanded model incorporating 31 additional photometric images from 8 additional systems yields a near-identical mass distribution, confirming excellent model stability. We resolve a complex multi-axis post-merger system requiring five cluster-scale dark matter haloes, including a bimodal core with distinct haloes coincident with each brightest cluster galaxy. The remaining mass components are independently supported by kinematics of 291 cluster members ($σ_v=1960^{+84}_{-92}$ km s$^{-1}$), which reveal two new galaxy substructures - the northernmost of which we tentatively identify as the baryonic counterpart to our fifth dark matter halo. The cluster is an extraordinarily efficient lens, possessing an effective Einstein radius $θ_E=42.41^{+0.05}_{-0.04}{''}$ and an enclosed mass $M(<θ_E)=3.35^{+0.04}_{-0.03}\times10^{14}M_\odot$ for a source at $z_s=2$. For a high-redshift source at $z_s=9$, it produces a magnification cross-section of $A(>10)\simeq0.15$ arcmin$^2$ and $A(>30)\simeq0.020$ arcmin$^2$. This global lensing power surpasses all Hubble Frontier Fields clusters. In a regime where systematic uncertainties between mass models dominate high-redshift magnification errors, the stability of our reconstruction sets this lens apart. This combination of extreme lensing power and a robust mass model establishes SPT-CLJ1150-2805 as a premier cosmic telescope for high-redshift studies.

astro-ph.CO↗

arXiv2026

Not-quite-primordial black holes

We propose a new mechanism for the formation of seeds of supermassive black holes at early cosmic epochs. Our scenario explores density fluctuations that are enhanced relative to $Λ$CDM expectations, but with amplitudes that are not large enough to form primordial black holes, and that can still lead to collapsed dark matter halos at very early times. For halos forming prior to $1+z \approx 200$, the Cosmic Microwave Background (CMB) is energetic enough to suppress the formation of molecular hydrogen, hence preventing cooling and fragmentation, as a consequence of which baryons falling into the potential well of the halo may undergo ``direct collapse" into a black hole. We show using a few illustrative models how this mechanism may account for the abundance of high-redshift black holes inferred from observations by the \textit{James Webb Space Telescope} while remaining consistent with limits from CMB spectral distortions. Limits on the primordial power spectrum are also derived by requiring that the universe not re-ionize too early.

astro-ph.CO↗

arXiv2026

Overmassive No More: The Case for Little Red Dots Hosting Black Hole Seeds as Massive as Single Supermassive Stars

Little Red Dots (LRDs) display singular properties unlike any known class of AGN or galaxies, motivating novel mass estimators for their central engines. Inspired by their similarities to stellar phenomena, here we interpret the LRD continuum as being produced by a pseudo-photosphere. We fit tailored stellar atmosphere models to host-subtracted LRD central engines ("black hole stars," BH*s) represented by stacks of $117$ objects. Typical BH* continuum spectra are well fit by models in a narrow range of temperatures ($T_{\rm eff}\approx4200-4800$ K), with bolometric luminosities $\approx10^{43-45}$ erg s$^{-1}$, implying pseudo-photospheric radii $\approx700-2000$ au. Based on these parameters, we explore four different approaches to deriving BH* masses: 1) using the surface gravity from atmosphere models; 2) appealing to the resemblance to super-Eddington phenomena; 3) approximating the escape velocity from the outflowing material; and 4) exploiting the lack of variability to bound the dynamical time. For the typical BH*, all of these methods yield remarkably consistent masses of $\approx10^{4-5}\,M_\odot$, implying a highly super-Eddington luminosity of $L_{\rm{bol}}/L_{\rm{Edd}}\sim5-50$. These mass estimates place BH*s within the scatter of the local scaling relation between black hole mass and host galaxy stellar mass, providing a self-consistent alternative to "overmassive" black holes that lie $2-3$ dex above it. Crucially, our derived masses are consistent with BH*s arising from single supermassive stars (SMSs), whose masses cannot exceed $\approx10^{5-6}\,M_\odot$ due to general relativistic instabilities. Furthermore, for our derived $L_{\rm bol}/L_{\rm Edd}$, the sharp cutoff of the LRD luminosity function matches the maximum theoretical mass of an SMS. With LRDs, we may therefore be directly observing the birth of heavy black hole seeds.

astro-ph.GA↗

arXiv2026

The black hole occupation fraction as a fossil record of seeding, dynamics, and galaxy assembly

The black hole occupation fraction (BHOF) is a powerful but intrinsically layered diagnostic of massive black hole (BH) seeding and subsequent galaxy assembly. We measure the total, central, and wandering BHOF in the ASTRID cosmological hydrodynamical simulation from $z=5$ to $z=0$ in galaxies with stellar masses ranging from $10^7$-$10^{12} \, \mathrm{M}_\odot$. For the full population, the total BHOF remains close to unity across most stellar masses and redshifts, reflecting efficient seeding in eligible halos. At low stellar masses, the central BHOF declines toward the present day, while the wandering BHOF rises, indicating that mergers deposit BHs at off-center locations in galaxies. Compared to these full-population BHOFs, the heavy-seed BHOFs are substantially smaller at the low-mass end. The active BHOFs are smaller at all stellar masses, especially at late times, demonstrating that active galactic nuclei (AGN)-selected samples trace duty cycles rather than intrinsic BH occupation. At $z=0$, primary (central) galaxies have higher BHOFs than satellites, and star-forming low-mass galaxies preferentially host wandering rather than central BHs. Our results show that the BHOF, when decomposed by BH location, seeding history, accretion state, and larger-scale galactic environment, encodes a rich fossil record of BH origins and dynamics.

astro-ph.GA↗

arXiv2026

AGN-DB: A Unified Multi-Wavelength Database of Active Galactic Nuclei

We present the Active Galactic Nuclei Database (AGN-DB), a comprehensive, multi-wavelength catalog compiled from more than 100 publicly available AGN catalogs and samples released by the end of 2025, spanning radio to $γ$-ray wavelengths. The database contains approximately 8.1 million unique sources, approximately 7.8 million of which remain after flagging stellar contaminants, and approximately 6.8 million of these are classified as AGN. Source cross-matching across catalogs is performed using Lyra, a Bayesian likelihood-ratio framework that jointly considers positional uncertainties, source densities, and photometric information to compute posterior match probabilities. The resulting catalog provides astrometric coordinates, redshifts, photometry, and classifications for each unique source. All multi-catalog provenance is preserved. For every property, we store the full array of values and originating catalog identifiers, enabling multi-epoch and multi-survey analyses. In this paper, we describe the AGN-DB pipeline, including the cross-matching methodology, and present the statistical properties of the v1.0 catalog. AGN-DB is designed to enable population studies, spectral energy distribution modeling, AGN classification, and variability analyses at an unprecedented scale. Its pipeline is designed to facilitate the integration of new catalogs, allowing AGN-DB to be updated regularly, with releases planned at least annually.

astro-ph.GA↗

arXiv2026

Not all cores are equal: Phase-space origins of dynamical friction, stalling and buoyancy

Dynamical friction governs the orbital decay of massive perturbers within galaxies and dark matter halos, yet its standard Chandrasekhar formulation fails in systems with cores of (roughly) constant density, where inspiral can halt or even reverse, phenomena known respectively as core stalling and dynamical buoyancy. Although these effects have been observed in simulations, the conditions under which they arise remain unclear. Using high-resolution N-body simulations and analytic insights from kinetic theory, we systematically explore the physical origin of these effects. We demonstrate that the overall distribution function (DF) of the host, not just its central density gradient, determines the efficiency and direction of dynamical friction. Core stalling arises when the perturber encounters a plateau in the DF, either pre-existing or dynamically created through its own inspiral, while buoyancy emerges in systems whose DFs possess an inflection that drives an unstable dipole mode. We show that double power-law density profiles with rapid outer-to-inner slope transitions naturally produce such DF features, which is why structurally similar cores can yield radically different dynamical outcomes. Our results provide a unified framework linking the phase-space structure of galaxies to the fate of embedded massive objects, with direct implications for off-center AGN, the dynamics of nuclear star clusters, and the stalled coalescence of black holes in dwarf galaxies and massive ellipticals.

astro-ph.GA↗

arXiv2026

Host Dependence and Line-of-Sight Effects on Galaxy-Galaxy Strong Lensing in Clusters

The cross section for galaxy-galaxy strong lensing (GGSL) events in galaxy clusters has repeatedly been found to be higher in observations than in cosmological simulations. We revisit this discrepancy using updated simulation methodology and investigate the dependence of the GGSL probability, $P_{\rm GGSL}$, on host-cluster lensing properties, baryonic physics, and correlated and uncorrelated line-of-sight structure. We find that correlated material within $\sim 35$ cMpc of the cluster along the line of sight enhances $P_{\rm GGSL}$ by a few percent for typical systems and by up to $\sim15\%$ for the most efficient lenses. At fixed cluster mass, dark-matter-only simulations yield GGSL probabilities up to an order of magnitude lower than hydrodynamical simulations. We also find a strong dependence on the host-cluster Einstein radius, with an approximate scaling $P_{\rm GGSL} \propto θ_{\rm E}^{2}$. Matching simulated and observed clusters in both mass and Einstein radius seems to reduce the discrepancy relative to previous comparisons. However, our analysis does not clearly resolve the GGSL discrepancy, as the inferred tension depends strongly on the field-of-view definition: square fields are approximately consistent with simulations, while cluster member-bounded fields yield observed probabilities a factor of $\sim 2-3$ higher. Until observations and simulations share a matched selection function and matched measurement methodology, the residual tension cannot be cleanly attributed to either astrophysics or cosmology.

astro-ph.CO↗

arXiv2026

Primordial Black Holes as Cosmic Architects: Imprints of an extended mass function

Primordial black holes (PBHs) remain compelling dark-matter candidates and possible relics of early-Universe physics, with observable imprints across both cosmological structure formation and gravitational-wave astronomy. We investigate the consequences of a PBH population described by an extended, physically motivated mass function shaped by features in the thermal history of the early Universe. We compute the associated Poisson contribution to the matter power spectrum and propagate its effects to the halo mass function, the cosmic star-formation rate density, and the reionization history. The PBH component produces a moderate enhancement of small-scale power, leading to earlier low-mass halo formation and a correspondingly mild increase in the high-redshift star-formation rate density while remaining consistent with current constraints on the Thomson optical depth. We then evaluate the merger-rate distribution expected for current and future gravitational-wave detectors. In the stellar-mass regime, the predicted PBH binary population occupies the region probed by LIGO-Virgo-KAGRA and can contribute to the observed compact-object merger population. For LISA, the detectable signal is dominated by intermediate-mass binaries with component masses of $10^3$-$10^4\,M_\odot$, with cumulative rates of order a few events per year extending to redshifts as high as $z \sim 50$. The detection of such high-redshift intermediate-mass black hole mergers would constitute a distinctive signature of a primordial origin, providing evidence that PBHs contribute non-negligibly to the dark matter budget and may have served as early seeds for the supermassive black holes observed at later cosmic epochs.

astro-ph.CO↗

arXiv2026

Tracing black hole and galaxy growth across environments since cosmic noon

The distribution of systems in the black hole (BH) mass-stellar mass ($M_\mathrm{BH}-M_\star$) plane encodes both the integrated growth of galaxies and their central black holes, and the processes that shape their evolution. Using the ASTRID and TNG300 cosmological simulations, we track massive BHs from cosmic noon ($z=2$) to $z=0.5$. TNG300 repositions BHs to the centers of their host galaxies at every time step, while ASTRID instead advances them under the resolved gravitational forces plus a subgrid dynamical friction model, allowing BHs to wander off-center when orbital decay is inefficient. We follow the BHs rather than their original host galaxies, thereby capturing central BHs, BHs in satellites, and wandering BHs. We find that central BHs in both simulations evolve along a tight, nearly redshift-invariant $M_\mathrm{BH}-M_\star$ relation that is broadly consistent with local empirical constraints. Departures from this relation trace distinct evolutionary channels in which mergers play a key role. Major galaxy mergers drive BH-BH coalescence that dominates the growth of the most massive central BHs. These BHs subsequently quench their hosts through active galactic nucleus (AGN) kinetic feedback. Minor mergers tidally strip satellites to lower $M_\star$ at nearly fixed $M_\mathrm{BH}$, producing weakly accreting, overmassive central BHs in gas-poor systems. In ASTRID, satellite accretion and inefficient dynamical friction generate wandering BHs that are undermassive relative to their new hosts and experience minimal accretion or merger-driven growth. A BH's location in the $M_\mathrm{BH}-M_\star$ and specific BH accretion rate-specific star formation rate planes is therefore a fossil record of its dynamical, accretion, merger, and feedback history.

astro-ph.GA↗

arXiv2026

The Road to Normalcy: Environment-Driven Evolutionary Pathways for Primordial Black Holes

We investigate how cosmological environment regulates the evolution of primordial black hole (PBH) seeds in the early universe using a suite of hydrodynamical simulations. Unlike traditional seeding channels, PBHs provide early BH seeds without the need of special conditions for gas collapse/fragmentation that favor overdense regions, thus covering diverse large-scale environments. We find that PBHs follow distinct evolutionary pathways depending on the gas supply and halo assembly history. In underdense regions, limited inflow suppresses both accretion and star formation, producing faint, metal-poor systems, while in overdense environments, sustained gas inflow drives rapid BH growth and the formation of compact, centrally concentrated stellar components. These differences lead to large variations in BH-to-stellar mass ratio, metallicity, and morphology, collectively bracketing a range of possible evolutionary pathways for PBH-seeded systems. We show that compact, BH-dominated sources resembling recently observed Little Red Dots naturally arise as one phase within these evolutionary pathways before evolving into more extended galaxy--AGN systems. Our results suggest that both the initial seed properties and cosmological environment jointly shape early BH--galaxy co-evolution, while subsequent environmental regulation can erase the memory of the initial seeding channel.

astro-ph.GA↗

arXiv2026

Episodic super-Eddington accretion as a clue to Overmassive Black Holes in the early Universe

Early JWST observations are providing growing evidence for a ubiquitous population of accreting supermassive black holes (BHs) at high redshift, many of which appear overmassive compared to the empirically-derived local scaling relation between black hole mass and host galaxy stellar mass. In this study, we leverage predictions from the semi-analytical Cosmic Archaeology Tool (CAT) to reconstruct the evolutionary pathways for this overmassive BH population, investigating how they assemble over cosmic time and interact with their host galaxies. We find that the large $M_{\rm BH}-M_{\rm star}$ ratios can be explained if light and heavy BH seeds grow by short, repeated episodes of super-Eddington accretion, triggered by major galaxy mergers. On average, we find that BH-galaxy co-evolution starts in earnest only at $z < 8$, when $\simeq 30\%$ of the final galaxy stellar mass has formed outside the massive black hole host. Our model suggests that super-Eddington bursts of accretion last between $0.5-3$ Myr, resulting in a duty cycle of $1-4 \%$ for the target BH sample. The boost in luminosity of BHs undergoing super-Eddington accretion helps explaining the luminosity function of Active Galactic Nuclei observed by JWST. At the same time, a large population of these overmassive BHs are predicted to be inactive, with Eddington ratio $λ_{\rm Edd} < 0.05$, in agreement with recent observations.

astro-ph.GA↗

arXiv2026

LoVoCCS. III. Third Generation Pipeline & The Hercules Supercluster

The Local Volume Complete Cluster Survey (LoVoCCS) is a volume-complete survey of over one-hundred nearby ($0.03 < z < 0.12$), X-ray luminous ($L_{500} > 10^{44} \text{ erg s}^{-1}$) galaxy clusters in the southern sky. Observations for the survey concluded in December 2025, reaching Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) Year 1-2 depth in each field and providing observations with $\lesssim 1"$ seeing for weak lensing science. In this paper, we present the latest pipeline for reducing observations using the third-generation of the LSST Science Pipelines. We use recent observations of the Hercules Supercluster to validate the pipeline's data-products and conduct an extensive multi-plane weak-lensing analysis of a $\sim 16 \text{ deg}^2$ complex covering Abell 2147, 2151, 2152, and several additional structures. We confirm that the dynamical mass of the complex is biased due to the dynamical state of Abell 2147, which is consistent with being $\sim 0.2-0.4 \text{ Gyr}$ out-of periapsis, and estimate that the total mass of the supercluster is $8.9^{+1.7}_{-1.4} \times 10^{14}~M_{\odot}$.

astro-ph.GA↗