Abstract It is still debating on whether the disc is magnetically arrested in M87. We assume that a weak external magnetic field is dragged inwards by the accretion disc, which is substantially enhanced to drive strong jets near the black hole horizon via Blandford-Znajek mechanism. The jet power of M87 has been well constrained with the observational data, while the accretion rate in the inner region of the accretion flow in M87 is estimated by fitting the multi-waveband continuum spectrum and the data of the Faraday rotation measurement, with which the surface density of the disc is derived. Our calculations show that, in order to produce the observed jet power $P_{\rm jet}=3.2\times 10^{43}~\rm erg~s^{-1}$, an external field with several hundred $\mu \rm G$ at the outer edge of the disc is required to be amplified in the disc to hundreds G at the BH horizon, and the accretion flow in M87 must be magnetically arrested. A standard and normal evolution (SANE) disc is allowed in M87, only if the jet power is significantly lower than $\sim 1.75 \times 10^{43} \rm erg~ s^{-1}$,
Abstract While long-term radial velocity (RV) monitoring has successfully mapped blue straggler star (BSS) multiplicity in nearby, unreddened open clusters, such spectroscopic surveys are observationally prohibitive for distant (d > 2 kpc) and moderately reddened Galactic clusters. To bypass this limitation, we present a general statistical framework that combines an empirical colour–magnitude diagram (CMD) displacement parameter (ηbinary) with Gaia astrometric noise (renormalised unit-weight error, RUWE) to diagnose BSS multiplicity on a population level. We apply this methodology to the intermediate-age open cluster Haffner 10 (d ≃ 3.5 kpc, AV ≃ 1.2 mag) as a representative test-bed. Out of 52 identified BSS candidates, the population is strongly redward-dominated (47 stars, fred ≃ 0.90). After correcting for differential reddening, we find a non-negligible residual main-sequence colour dispersion (σΔC = 0.105 mag), showing that individual CMD positions are insufficient to identify formation channels. However, a Spearman rank test reveals a positive correlation between the continuous CMD displacement ηbinary and RUWE (ρS = 0.35, p = 0.011), indicating that redward-displaced BSS candidates tend to show enhanced astrometric residuals. We compare our results with a literature sample of well-studied open clusters (M67, NGC 188, Melotte 66, and NGC 7789) to discuss how observational limitations and dynamical states shape the observed BSS configurations. Our approach offers a highly cost-effective template for characterizing BSS origins in distant open clusters where spectroscopy is currently unavailable.
Abstract Self-interacting dark matter (SIDM) influences halo structure through collisional heat transport and offers potential solutions for a range of small-scale puzzles in structure formation. SIDM creates thermalized cores in low-mass haloes, which may account for the observed cored dwarf galaxies. In the meantime, during the late-time gravothermal core collapse, SIDM can produce dense low-mass DM haloes and substructures that have been detected through perturbations to cold stellar streams and strong gravitational lenses. In this work, we present a new Monte-Carlo SIDM implementation in the moving-mesh code arepo-2, designed for efficiency, scalability, and extensibility. The central feature of the implementation is a dedicated DM-only neighbour-search tree that decouples the scattering solver from gravity. This preserves compatibility with the hierarchical time integration used by arepo-2 while leaving the optimized gravity solver unconstrained. A pairwise communication scheme between MPI tasks allows tracking multiple scattering events in a single timestep while conserving momentum and energy and maintaining parallel consistency by construction. This is complemented by a per-pair timestep criterion that significantly reduces unnecessary timestep restrictions. The implementation natively supports velocity-dependent cross-sections and inelastic interactions, while a compact interface is designed for additional SIDM physics to be implemented without knowledge of the parallelization layer. We validate the implementation for isotropic, elastic scattering using a suite of idealized and cosmological tests. We assess performance and scalability in isolated core-collapse simulations and in cosmological boxes, both DM-only and with baryons. Except during the late stages of gravothermal collapse, SIDM simulations incur only modest overhead relative to the corresponding CDM runs and are substantially faster than the previous SIDM implementation in arepo-1.
ABSTRACT We detect the kinetic Sunyaev–Zeldovich imprint of peculiar motions of galaxy groups and clusters, using the photometric Dark Energy Spectroscopic Instrument Legacy Surveys together with cosmic microwave background (CMB) maps from the Atacama Cosmology Telescope (ACT). We develop a comprehensive forward model based on the AbacusSummit cosmological simulations: Mock galaxy group catalogues and synthetic kinetic Sunyaev–Zeldovich (kSZ) maps are generated, together with a reconstructed peculiar velocity field that allows for photo-z errors, redshift-space distortions, and survey masks. We investigate possible contamination from the cosmic infrared background (CIB), finding that CIB effects are subdominant to the kSZ signal in the relevant ACT frequency channel. We then predict the kSZ signal expected when stacking CMB temperature maps around groups, taking account of their estimated radial velocities. Comparing the model with observations, we are able to constrain the total baryon fraction within haloes, as well as their internal gas profiles. We find evidence for mass dependence of the halo baryon fraction within the virial radius. The gas fraction in massive groups is consistent with the universal baryon fraction, but low-mass groups ($10^{12.5} \lesssim M\, /\, h^{-1}\, \mathrm{M}_\odot \lesssim 10^{14}$) are depleted to $0.38 \pm 0.11$ times the universal baryon fraction. We find this low virial baryon fraction to be consistent with an extended gas profile, for which the total baryon content reaches the universal value well beyond the virial radius. This conclusion is consistent with previous analyses using X-ray, kSZ, and weak lensing, and plausibly reflects energetic feedback processes from the galaxies in these haloes.
The properties of stellar bars play a crucial role in determining the bar-driven secular evolution in disc galaxies. However, a systematic observational study of the evolution of several bar properties (such as strength and length) across cosmic time is largely missing. In this paper, using a sample of 625 barred galaxies, taken from SDSS, HST COSMOS, and JWST CEERS surveys, we systematically investigate the evolution of bar properties over redshifts (0.02 ≲ z < 3) by making a novel usage of dark gap (preferential light deficit along the bar minor axis) properties as a proxy for bar properties. We show that the dark gap strength (Δμ_ max) exhibits a weak evolution, increasing from higher redshifts (z ∼ 2.5) and slightly declining towards lower redshifts (z < 0.05). Conversely, the extent of dark gaps (R_ DG, R_ dark; normalised by bar length) decreases moderately from z ≥ 1.4 and remains constant thereafter. Our results suggest that bar formation and the initial rapid growth phase occur before z ∼ 3, followed by mild growth towards lower redshifts. We also find R_ dark to be a better proxy (as compared to R_ DG) for estimating bar length, supporting earlier theoretical studies. Furthermore, the Δμ_ max shows a weak but statistically significant correlation with bar-to-total light ratio (Bar/T) and bar ellipticity (ε_ bar). Studies of the redshift evolution of bar properties over such an extensive redshift range as done here are instrumental in constraining the bar-driven evolution at early cosmic times.
ABSTRACT We provide the first analytical and numerical calculations of the joint onset/termination rate–duration relationship for stochastic Babcock–Leighton dynamo models, and compare them with the recently reported relation from seven Holocene grand minima ($R^{2}_{\rm onset} = 0.76$ and $R^{2}_{\rm term} = 0.95$). We employ the standard amplitude-equation truncation of the stochastic dynamo near its Hopf bifurcation – a 1D Langevin equation for the cycle-amplitude envelope with multiplicative noise. By fixing the single-free parameter via simultaneous calibration against four independent Holocene observables, we integrate $\sim 3.3 \times 10^{6}$ yr of Monte Carlo realizations. Two main results follow. First, the population rate–duration relation is a power law with slope $-0.55 \pm 0.01$ for both phases, with a small structural asymmetry in goodness of fit $\Delta R^{2}_{\rm pop} = 0.08 \pm 0.02$; both are derived analytically from the Ornstein–Uhlenbeck escape statistics of the underlying Langevin equation and are insensitive to the model parameters. Second, the apparent asymmetry $\Delta R^{2} \approx 0.19$ between onset and termination in the observed sample is dominated by small-sample statistical noise of a single-mechanism null at $N=7$, of which only $\sim 0.08$ is structural; both observed values lie within the predicted bootstrap distribution ($p_{\rm onset} \approx 0.34$ and $p_{\rm term} \approx 0.05$, broadly robust to detector parameters and observational uncertainty). We predict that the apparent gap will relax toward $\sim 0.08$ as the high-resolution $^{14}$C catalogue is extended, and that $N \approx 15$ well-resolved terminations would suffice to distinguish the minimal stochastic null from a state-dependent threshold mechanism. The result supports the view that grand minima are stochastically forced excursions of a weakly non-linear dynamo near criticality.
Relativistic jets are observed in both stellar-mass black hole X-ray binaries (BHXRBs) and active galactic nuclei (AGNs), yet their bulk Lorentz factors differ systematically—those in black hole X-ray binaries are typically below ∼2, whereas AGN jets can reach ∼50. The origin of this discrepancy remains unclear. Searching the literature, we compile a sample of 333 AGNs with well-measured jet component motions, consisting of 270 quasars, 47 BL Lac objects, 10 FR I, and 6 FR II galaxies. We find that quasars/FR IIs exhibit minimal bulk Lorentz factors ranging from ∼1.0 to 41.5, with a mean of 11.5 (median 9.5). In contrast, BL Lac objects/FR Is show Γ_ jet∼1.0–21.9, averaging 4.2 (median 1.5). These values, particularly the median, closely resemble those of BHXRBs, implying a strong correlation between jet speed and accretion mode. The Lorentz factor of a magnetically driven jet is mainly determined by the ratio of the magnetic pressure to rest mass energy density at the jet base. In BL Lacs/FRIs/BHXRBs, the field is maintained by the advection-dominated accretion flow (ADAF), and the gas at the ADAF surface is magnetically driven into the jets. In quasars/FRIIs, the field is maintained by the disc, while the jet base is connected to the corona. Our model calculations show that the disc field is always much stronger than that of the ADAF, and therefore leads to a larger Γ_ jet, which can explain the systematic difference in Γ_ jet between these two types of sources.
Massive, star-forming clumps are regions of intensive star-formation that are commonly observed in high-redshift (z > 1) galaxies. Observations of low-redshift clumpy galaxy analogues are rare but the availability of wide-field galaxy survey data makes the detection of large clumpy galaxy samples much more feasible. We present a population of 12,790 star-forming clumps detected in a mass-complete sample of 5,395 star-forming galaxies (SFGs) at redshifts z≤0.32, located in the XMM-LSS, E-COSMOS and DEEP2-3 fields observed by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) and CFHT Large Area U-band Deep Survey (CLAUDS). The clumps were detected using an improved version of our Deep Learning (DL)-based object detection framework which uses the ZOOBOT foundation DL-model as a 'backbone' feature extractor. We determined the fraction of star-forming galaxies hosting at least one off-centre clump (f_clumpy) based on a clump definition that requires a clump-galaxy flux ratio in the CLAUDS u-band of ≥8%. We estimate f_clumpy to decrease from ∼31% at z∼0.3 to ∼23% at z ∼ 0.1, which aligns well with a low-redshift extrapolation of the clumpy fraction that is measured using high-redshift observations. At fixed redshift, f_clumpy is negatively correlated with the stellar mass and positively correlated with the specific star-formation rate (sSFR) of the host galaxies. When the clump definition is changed to include only clumps with a stellar mass of M_cl≥ 10^7 M_⊙, we observe a highly increased clumpy fraction of ∼60% that tends to increase with the stellar mass of the host galaxies but does not show a dependence on the sSFR of the host galaxies.
Large-scale spectroscopic surveys will need suitable benchmark stars that can be used to verify the performance of automatic pipelines. A promising type of object for this purpose is the detached eclipsing binary (DEB) containing an FG-star and a low temperature companion. For flux ratios ≲1 per cent, the spectra obtained for the binary will be almost identical to a single star. As the methods for obtaining accurate parameters for binaries are well established, they would be excellent benchmark candidates. We analyse a group of DEBs with M-dwarf companions using TESS light curves and high resolution spectroscopy from NIRPS and HARPS on the ESO 3.6-m telescope. We obtain accurate fundamental parameters for the stellar components. The secondary component is visible with cross-correlation, allowing them to be characterised as well. With the stellar parameters obtained from the analysis, we can measure precise effective temperatures from Gaia parallaxes and archival magnitude data. Chemical compositions of the primary stars are also extracted from the stellar spectra. In this analysis, the secondary components have minimal impact on determined spectroscopic parameters. Our radii and masses are characterised to within sub per cent precision as well as our primary effective temperatures. Beyond a new set of stellar benchmarks, the secondary components analysed in this work represent a well characterised sample of M-dwarf stars which will be useful to improve our understanding of low mass structure and evolution.
Strong gravitational lenses (SGLs) are rare systems whose discovery currently relies primarily on supervised machine learning methods trained on large simulated datasets. We present the first application of Astronomaly:PROTEGE to SGL discovery, demonstrating that a human-in-the-loop active learning framework can efficiently identify lenses in large imaging surveys without the need for simulated training data. We consider a sample of 3.7 million bright galaxies from the Kilo-Degree Survey (KiDS) DR4. Feature representations are extracted using a convolutional neural network pre-trained on the ImageNet dataset and subsequently fine-tuned on KiDS data using the self-supervised Bootstrap Your Own Latent (BYOL) framework. Within the embedding of these representations, the active learning loop of Astronomaly iteratively selects the most informative systems for expert inspection. A total of 3,000 objects are inspected across multiple rounds, yielding 34 high-quality (grade A/B) SGL candidates. On the basis that these systems occupy similar regions in the learned feature space, we expand this sample through nearest-neighbour similarity analysis. Including the active learning discoveries, we identify a total of 140 grade A/B candidates and more than 1,000 additional lower-confidence systems (grade C). Among the A/B candidates, 81 are newly identified, while approximately 22
H I gas traces the large-scale structure and provides the primary fuel for star formation. High-z protoclusters are ideal laboratories to study how H I gas is accreted and consumed during the formation of the most massive structures in the Universe. However, much remains unknown about the distribution and physical state of their H I gas. We examine a rare configuration in which a protocluster candidate is located in front of a quasar at z=3.09. Our spectroscopic campaign confirms a protocluster at z=3.079: however, no corresponding strong H I absorption is found in the background quasar spectrum. Instead, we serendipitously discover a prominent H I absorption feature at z∼ 3.01, offset by ∼ 60 cMpc from the centre of the protocluster. Spanning an exceptionally broad velocity range of ∼ 2000 km s^-1 (∼ 40 cMpc), this absorption is decoupled from the confirmed member galaxies. Detailed kinematic modelling reveals this absorption comprises five distinct components rather than a single cloud. Moreover, one of these components exhibits a super-solar metallicity ([O/H] = +1.19^+0.91_-0.78). We propose two physical scenarios for this unique system: (1) an additional, hidden massive protocluster along the line of sight, and/or (2) metal-rich outflows and metal-poor inflows driven by a single massive galaxy. The discovery highlights that while protoclusters are not universally associated with strong H I absorption, targeting the strong H I absorbers may serve as a beacon for uncovering massive, metal-rich protoclusters or complex gas kinematics in the early Universe.
ABSTRACT We present a study of the magnetic field (B-field) in the Eagle Nebula (M16) using data from the James Clerk Maxwell Telescope B-fields In STar-forming Region Observations survey. We extend our previous study of the well-known ‘Pillars of Creation’ region of the nebula to study two other structures in the region, the ‘Spire’ and the bright-rimmed cloud known as ‘SFO30’. These structures show similar B-field morphologies to the Pillars. We calculate B-field strengths using the Davis–Chandrasekhar–Fermi method and thereby estimate the magnetic potential energy in each of these regions for comparison with the local gravitational, turbulent, and thermal energies, as well as the pressure energy of the shocks from nearby O-type stars. We find approximate equipartition between the energies supporting the regions and those tending towards collapse, with the B-field support playing a significant role. This agrees with our earlier hypothesis that B-fields help support pillar-like structures in molecular clouds and make them longer-lived than they would otherwise have been.
We present analyses of new and archival Chandra and NuSTAR data on two old millisecond pulsars, a young highly-energetic pulsar, and a young neutron star. PSR J1810-0623 is a recently-discovered 4.55 ms radio pulsar in a binary with a possible carbon-oxygen white dwarf companion. We tentatively detect the pulsar for the first time in X-ray using a new short Chandra HRC-I observation. Its faintness suggests a distance more in accord with the further ( 1 kpc) of its dispersion measure-inferred distances. PSR J1933-6211 is a 3.54 ms radio pulsar also with a carbon-oxygen white dwarf companion. Our first-time X-ray detection in an archival HRC-S image indicates its X-ray luminosity is similar to that of the 1.9 Msun pulsar PSR J1614-2230. Next, PSR J1813-1749 is a 1-2 kyr pulsar with one of the highest known spin-down luminosities. We measure its spin period of 44.7 ms using 2025 NuSTAR and 2026 Chandra ACIS-S data and update its spin evolution model. We show for the first time the pulse profile of PSR J1813-1749 at 3-79 keV, and we find that the spectra of the pulsar and pulsar wind nebula at these energies did not change significantly between observations in 2018 and 2025. Finally, for the 5-10 kyr neutron star CXOU J182913.1-125113 in the supernova remnant G18.95-1.1, we combine ACIS-I observations from 2009 and 2024 to better measure the neutron star's spectrum.
Abstract We investigate how short-distance regularization may affect primordial-black-hole (PBH) dark matter at both formation and late times. On the formation side, we develop an effective model of primordial collapse to regular black holes during radiation domination by promoting static Hayward-, Bardeen- and Dymnikova-type mass profiles to local excess-mass prescriptions within the Misner–Sharp and compaction-function framework. The resulting regular core suppresses short-distance compaction and raises the threshold for horizon-bearing collapse; in the Hayward case, the leading correction scales as $(\ell ^2/R_m^2)$, where (ℓ) is the regularization scale and (Rm) is the radius of maximum compaction. The common sign is a feature of the three effective maps studied here, whereas the magnitude of the true nonlinear collapse-threshold shift is model dependent. On the late-time side, we adopt the Hayward, Bardeen and Dymnikova geometries as benchmark evaporation completions and show that their finite-mass extremal endpoints obey the universal geometric scaling (TH∝(M − M*)1/2). Within the Stefan–Boltzmann vacuum approximation, this implies asymptotically slow evaporation, (M(t) − M*∝t−1), and motivates a transport framework for evolving PBH populations and their gamma-ray signal. Short-distance regularization therefore acts in opposite directions on PBH dark matter, suppressing primordial production while enhancing late-time survival. We argue that any realistic assessment of nonsingular PBH dark matter should treat these two sectors simultaneously. The physical-unit evolution, however, establishes no observationally allowed dark-matter region; it provides only branch-consistent mass-flow and single-energy emission diagnostics.
Higher-order protostellar systems (≥3 components) are commonly observed in the early stages of low-mass star formation. A persistent question in star formation and evolution is whether these higher-order protostellar systems survive as gravitationally bound systems or dissolve into binaries over time. We explore this question with a case study of the embedded quadruple protostellar system VLA1623 and its observational constraints, assuming that the components A1, A2, B, and W are gravitationally bound. Using N-body simulations, we run a grid of models considering gravity, mass accretion onto protostars, the presence of the protostellar cloud core, and its dispersal. The simulations are integrated over a period of 8 Myr to take into account the evolution from the protostellar phase (Class 0 and I, 1 Myr), through the pre-main sequence (Class II and III, 2 – 3 Myr), and into the main sequence (4 Myr). Our results show that VLA1623 has a probability of 30
We investigate the population of open clusters in the Solar Neighbourhood and model the effect of encounters with giant molecular clouds (GMCs) over the last 1 Gyr. We combine a Galactic model with N-body simulations of 20692 unique clusters in the mass range [50-24000] M_⊙. Each cluster is simulated twice: with and without tidal forces from the GMCs. We find that an initial cluster mass function truncated at ∼ 9000 M_⊙ best reproduces the observed mass function evolution. For the age function, the observations show a decline in clusters for ages older than ∼ 1 Myr, whereas our simulated clusters show a decline after ∼ 50 Myr. The observed early disruption suggests that some clusters form supervirial, whereas our simulated clusters are created in virial equilibrium. Low-mass (<600 M_⊙) clusters are most sensitive to GMC encounters, which accelerate their disruption in the first ∼ 200 Myr. After ∼ 500 Myr, the impact of GMCs becomes irrelevant since the clusters will have been destroyed regardless of whether they experience GMC encounters or not. The survival of intermediate-mass (600-6000 M_⊙) clusters is significantly reduced by GMCs at ages up to 1 Gyr. High-mass (>6000 M_⊙) clusters survive to 1 Gyr with minimal disruption with or without GMCs. We find that clusters that have had strong GMC encounters within the last 20 Myr should have tidal tails that are randomly orientated with respect to the Galactic centre.
Recent observations have found many ultra-compact dwarf galaxies (UCDs) that contain massive black holes (MBHs) typically consisting of 10%-15% of their total mass, with some as high as 40%. However, whether UCDs initially started with MBHs or grew from intermediate-mass black holes (IMBHs) is unclear. We propose a mechanism in which AGB stars have their gas ejected which forms an accretion disk around an IMBH to fuel BH growth. We used smooth particle hydrodynamical simulations to (i) model the creation and evolution of gas disks that can finally evolve into accretion disks and to investigate (ii) how the properties of the gas disk depend on the model. We find that the amount of mass in the disk increases more with UCD mass than with IMBH mass. For lower-mass IMBHs of 100 M_⊙, a majority of the gas mass present can be trapped in a disk, leading to the idea that lower-mass BHs can utilise the proposed mechanism. The main mechanism working against accretion disk formation is the creation of new stars within the disk, not just through the removal of gas but through gravitational disruption as well. Finally, an estimation of the total BH growth provides a list of observed UCDs which could have formed MBHs using the proposed mechanism which can be useful for verifying the proposed mechanism. Future simulations aimed at modelling the formation of such UCDs can be employed to provide a full picture of the results presented in this paper.
We present the first atmospheric retrieval analysis of two compositional benchmark mid-L dwarfs – SDSSJ141659.78+500626.4 and GJ 499 C – using the Brewster retrieval framework, where the wide benchmark nature of these systems provides independent constraints on age and bulk composition from their stellar primaries. These targets were observed with JWST using NIRSpec Prism and MIRI LRS, providing low-resolution (R ∼ 100) spectra between 0.6–14.0 m with high signal-to-noise ratios (SNR ∼100 – 600). For SDSSJ141659.78+500626.4, the retrieved cloud combination of a high-altitude enstatite slab and low-altitude iron deck clouds matches phase-equilibrium predictions based on the primary star's Mg/Si ratio. We retrieve a super-solar C/O = 0.71^+0.01_-0.01 and slightly metal-rich [M/H] = 0.22^+0.03_-0.03. This C/O ratio can only be reconciled with the value inferred for the primary if additional oxygen sequestration beyond the retrieved cloud mass is present, or if there are uncertainties in the adopted opacities or other model deficiencies. The inferred [C/H] and [O/H] are 0.31±0.03 and 0.19±0.03, respectively, which are consistent within the relatively large uncertainties of the host star abundances. For GJ 499 C, the retrieved silicon-monoxide and forsterite slab clouds are difficult to explain with simple phase-equilibrium assumptions, yielding Mg/Si ∼ 1.9. We estimate C/O = 0.69^+0.02_-0.02 and [M/H] = 0.13^+0.04_-0.06. For both objects, the inferred radii of 0.85^+0.01_-0.01 R_Jup and 1.00^+0.02_-0.02 R_Jup and masses of 73.7^+4.9_-9.2 M_Jup and 68.0^+8.5_-12.7 M_Jup are consistent with evolutionary models and system ages, highlighting the plausibility of our results.
While Digital sky surveys provide excellent throughput of image data and can cover a large footprint, their imaging power is normally inferior to that of space-based telescopes. Space-based telescopes, on the other hand, provide excellent imaging power and can image the deep Universe, but cannot provide the same throughput as advanced ground-based sky surveys. Here, we utilize generative AI to elevate the quality of galaxy images taken by ground-based telescopes to the level of details enabled by space telescopes. The solution is based on the nature of galaxy shapes, allowing generative AI trained on space-based images to convert weak signal into detailed and clear galaxy images. The method allows for combining the high throughput of ground-based sky surveys with the image quality of space-based telescopes. The source code for the method is available, as well as paired training data and a catalog of 63,202 galaxy images enhanced by the proposed method. We also provide a software tool that encapsulates the entire pipeline and the custom generative AI model to generate galaxy images with enhanced quality.
ABSTRACT Active galactic nucleus feedback is a key piece of galaxy evolution but is difficult to model due to its high specific energies, multiphase nature, and limited simulation resolutions. Arkenstone is a subgrid framework for representing multiphase flows in coarse-resolution simulations that has been used to model stellar feedback-driven galactic winds. It ensures the correct treatment of high specific energy feedback that would otherwise be challenging to model accurately in Lagrangian simulations. We introduce the new Arkenstone BH model, which extends the Arkenstone framework to model black hole feedback. We focus on describing the first piece of this framework, which follows the hot, high specific energy phase of these outflows. The second piece, which treats their multiphase structure with a scheme for modelling unresolved cold clouds, will be implemented and described in a later paper. We present Arkenstone BH in simulations of an isolated galaxy to demonstrate the framework and its ability to capture high specific energy feedback that interacts only weakly with cold, dense gas. We show how these energetic outflows suppress star formation in our isolated galaxy by counteracting the inflow of gas from the circumgalactic medium into the interstellar medium. This work is part of the ‘Learning the Universe’ collaboration, which aims to understand the Universe’s underlying physics and initial conditions.
