Cosmology and Nongalactic Astrophysics
Revisiting the missing mass problem in MOND for nearby galaxy clusters
Dong Zhang, Akram Hasani Zonoozi and Pavel Kroupa
In the framework of Milgromian dynamics (MOND),
galaxy clusters are known to exhibit a residual missing mass problem, with the baryonic mass falling short of the dynamical mass by about a factor of two. The
baryon content of clusters is dominated by the intracluster medium (ICM), while the
stellar contribution depends sensitively on the assumed
stellar initial mass function (IMF). We re-evaluate the
stellar and remnant masses in
galaxy clusters by adopting the integrated
galaxy-wide initial mass function (IGIMF) theory, which accounts for the dependence of the IMF on
galaxy properties and
star formation histories. Massive elliptical
galaxies, characterized by high
metallicities and short formation timescales, are inferred to form with top-heavy IMFs, leading to a substantial population of
stellar remnants. Using observational data from WINGS and 2MASS for 46 nearby (z < 0.1)
galaxy clusters, we compute
stellar, remnant, and intracluster light masses and combine them with previously derived ICM masses. The resulting total baryonic masses are compared to MOND dynamical masses inferred from hydrostatic
equilibrium. We find that the baryonic mass in
stars, remnants and the ICM accounts for at least $88^{+5+2}_{-4-1}\%$ of the MOND dynamical mass. This constrains the kick velocities of the remnants and substantially alleviates the missing mass problem for
galaxy clusters in MOND.
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Astrophysics of Galaxies
Yu Wang and Remo Ruffini
Quasars hosting $\gtrsim 10^{9}\,M_\odot$ black holes at $z>6$ challenge growth scenarios that start from light seeds and assume
accretion within already formed
galaxies. Motivated by the James Webb Space
Telescope (JWST) discovery of Little Red Dots (LRDs), which suggests that $\sim 10^{6}\,M_\odot$ black holes can be active in compact, pre-
galactic environments, we revisit early black hole growth with a minimal cosmology-based framework. We model the
accretion history as the smaller of the Bondi inflow rate and the Eddington-limited rate, where the Bondi rate is set by the supply of overdense
primordial gas whose density declines with
cosmic expansion, and the Eddington rate captures regulation by radiative feedback. By fitting the observed masses and luminosities of J0313–1806 ($z=7.64$) and J0100+2802 ($z=6.30$) with
Bayesian inference, we infer initial conditions that favor massive seed black holes with initial mass $M_0 \sim 10^{6}\,M_\odot$, formed at $z\sim20{-}30$ in environments with baryonic overdensity factors $f_\rho \gtrsim 50$ relative to the
cosmic mean. The resulting growth histories include a prolonged supply-limited stage, and they reproduce the observed
quasar masses without requiring sustained Eddington
accretion or any super-Eddington episodes. The inferred seed mass scale is consistent with black holes produced by the collapse of
quantum-degenerate
fermion dark matter cores, providing a physically defined pathway to massive seeds at the
redshifts implied by LRD phenomenology.
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Cosmology and Nongalactic Astrophysics
The Galaxy Bias Profile of Cosmic Voids:A Comparison of Void Finders
Ignacio G. Alfaro, Antonio D. Montero-Dorta, Jorge F. Bustillos et al. (+6 more)
Cosmic voids, the largest underdense regions in the Universe, provide unique laboratories for studying
galaxy formation and constitute powerful probes of cosmology. Recent work has shown that individual
galaxy bias (b_i), which quantifies how each
galaxy traces the underlying dark matter field, exhibits a characteristic radial dependence within spherical voids, defining a void bias profile in which
galaxies near void centers display systematically lower bias values. We investigate how the environmental modulation of individual
galaxy bias depends on the adopted void-finding
algorithm by comparing measurements across five distinct void definitions: spherical voids 'sparkling', watershed-based methods ('zobov' and 'revolver' in two modes), and free-form integrated-density voids ('popcorn'). We apply these complementary void-finding
algorithms to the same
galaxy sample drawn from the IllustrisTNG simulation (TNG300-1 at $z=0$) and compute individual
galaxy bias profiles as a function of distance from void centers. We quantify the correlation between b_i and the membership of the void catalogs and explore how this relationship varies with the integrated underdensity threshold for density-based methods. We find that the radial gradient of individual bias within voids, generally increasing from negative values at the void centers to higher values at the boundaries, is robust across most void definitions. However, density-threshold methods preferentially select
galaxies with b_i<0, while watershed methods without density constraints include substantial contamination from high-bias boundary
galaxies. The correlation between negative bias and void membership is systematically strengthened as the integrated underdensity threshold becomes less restrictive, with popcorn achieving the highest purity in isolating anti-biased populations.
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All authors Ignacio G. Alfaro, Antonio D. Montero-Dorta, Jorge F. Bustillos, Dante J. Paz, Andrés N. Ruiz, Andrés Balaguera-Antolínez, Ravi K. Sheth, Facundo Rodriguez, Constanza A. Soto-Suárez
Astrophysics of Galaxies
Shocks, Winds, and a Torus: The Large Binocular Telescope Interferometer (LBTI) Resolves the Active Nucleus of NGC 4151
Jacob W. Isbell, Steve Ertel, Makoto Kishimoto et al. (+12 more)
We present mid-infrared (MIR) observations of the Seyfert 1
galaxy NGC 4151 using the Large Binocular
Telescope Interferometer (LBTI). We took open-loop Fizeau images with 66-104 mas (5.8-9.1 pc) resolution in the N-band (at $8.7$ and $10.5~\mu m$), using the full resolution of the LBTI – equivalent to that of a 28.8 m
telescope. These images were complemented by AO imaging in the LM-bands ($3.7$ and $4.8~\mu m$), with 50-62 mas (4.4-5.4 pc) resolution. These images bridge the scales between previous Very Large
Telescope Interferometer (VLTI)/MIDI and VLT/VISIR data, delivering ELT-like imaging resolution in the N-band. We resolve a dusty
torus, (diameter 32 pc, PA$=125^{\circ}$), and detect dusty clouds within the narrow line region. Matching the resolution across four bands, we measured spatially-resolved SEDs of the central $\sim 100$ pc. Modified blackbody fitting revealed
dust temperature and extinction profiles, indicating both heating from the
accretion disk and additional shock heating due to the
radio jet. The spatial coincidence of ionized emission (e.g., [Fe II] and [O III]), extended MIR structures, and
radio features further supports the interpretation of shock heating. Comparison with NGC 1068 tests the Unified Model of Active
Galactic Nuclei (Unified Model of AGN): Structures are similar, despite differences in orientation and Eddington ratio. NGC 4151's
torus is smaller than NGC 1068's following a $r\propto L^{0.5}$ scaling. These thirty-meter-
telescope class observations of NGC 4151 and NGC 1068 highlight the need to revise MIR radiative transfer models of AGN to account for jet-related heating.
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All authors Jacob W. Isbell, Steve Ertel, Makoto Kishimoto, Gerd Weigelt, Jörg-Uwe Pott, Jared Carlson, Qixiang Duan, Violeta Gámez Rosas, Walter Jaffe, James Leftley, Daniel May, Romain. G. Petrov, Jennifer Power, Hélène Rousseau, Justin Rupert
Cosmology and Nongalactic Astrophysics
Wising up to CatWISE: using simulation-based inference to interpret the ecliptic bias and confirm the cosmic dipole excess
Oliver T. Oayda and Geraint F. Lewis
We apply Simulation-Based Inference ('SBI') to the
cosmic dipole problem for the first time, measuring the distribution of
quasar counts over the sky in the CatWISE2020 ('CatWISE') sample. We show that the quadrupole anisotropy in CatWISE can be attributed to the correlation between WISE's scanning law and photometric uncertainty in the $W1$ and $W2$ magnitudes, inducing an Eddington bias which varies with sky position. After explicitly modelling this with SBI, we use a neural likelihood
estimator to find the posterior distribution for CatWISE's dipole, confirming the presence of a dipole twice as large as the CMB expectation but more seriously misaligned with the CMB direction ($\approx 3 \sigma$). We also use our learned likelihood to infer the
Bayesian evidence, learning that models which increase the scale of CatWISE's photometric errors are most favoured. This is strong evidence that the sample's errors are underestimated or that there is an additional, unresolved systematic producing the same effect as Eddington bias. While our results indicate that the
cosmic dipole excess is a persistent issue for $\Lambda$CDM, we showcase that SBI can untangle the subtle and complex systematic issues affecting any sample derived from real astronomical data.
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Instrumentation and Methods for Astrophysics · Cross-listed from physics.hist-ph
Intereses convergentes: los años previos a la visita de Einstein a la Argentina en 1925
Alejandro Gangui
We analyze in some detail the years leading up to Albert Einstein's visit to Argentina, from the moment he rose to fame after the publication of the results of the 1919
solar eclipse, until his arrival at the port of Buenos Aires in March 1925. We will see that this major event in the country's cultural life did not arise from a
vacuum but was the product of diverse interests and unique international and local circumstances. The social and political situation surrounding the eminent scientist and the impetus provided by individuals and institutions in Buenos Aires played a decisive role, ultimately converging in the "successful" reception of this extraordinary figure in a country on the scientific periphery of the first quarter of the 20th century. We also review the written references and knowledge circulating in the local milieu on topics related to the theory of relativity in the years prior to his arrival in the country.
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High Energy Astrophysical Phenomena
ICM-SHOX III. The case of MACS J0018.5+1626, a radio relic that looks like a radio halo?
P. Domínguez-Fernández, J. A. ZuHone, E. M. Silich et al. (+9 more)
We present the first detailed numerical modeling of the
radio emission from MACS J0018.5+1626 as part of the Improved Constraints on Mergers with SZ, Hydrodynamical simulations, Optical, and X-ray (ICM-SHOX) project. By matching X-ray, thermal and kinetic Sunyaev–Zel'dovich, optical and
lensing observables to simulations, the ICM-SHOX pipeline indicates that MACS J0018.5+1626 is undergoing a binary merger close to pericenter passage and is observed along a line of sight nearly aligned with the merger axis. We perform three-dimensional magnetohydrodynamic simulations of binary cluster mergers coupled to tracer particles and a Fokker–Planck solver to model the
radio emission. Exploring variations in the most likely initial conditions within the ICM-SHOX parameter space, such as the relative cluster velocity and impact parameter, we find that the resulting merger configuration consistently produces two merger-driven shocks with typical average Mach numbers $\mathcal{M}_s \sim 2$–$3$ with corresponding standard deviations of $\sigma_{\mathcal{M}} \sim 0.5$–$1.5$. Within this framework, we examine the cluster conditions under which standard diffusive shock acceleration can reproduce LOFAR observations. In particular, we discuss the possibility that the apparent
radio halo seen by LOFAR arises from the superposition of two
radio relics viewed nearly face-on.
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All authors P. Domínguez-Fernández, J. A. ZuHone, E. M. Silich, E. Bellomi, J. Sayers, T. Mroczkowski, A. Botteon, R. J. van Weeren, L. Hernquist, G. Brunetti, J. Golec, S. Gupta
Earth and Planetary Astrophysics
On the forced orbital plane of the Hilda asteroids
Ian C. Matheson and Renu Malhotra
Hilda-group asteroids librate in Jupiter's interior 3:2 mean motion resonance. We estimate that the Hilda group is observationally complete up to absolute magnitude $H\leq16.3$. This provides a statistically useful sample of thousands of resonant objects, all within a narrow range of semimajor axes, to compare with theoretical expectaitons of their orbital distribution from dynamical theory. We use von Mises-Fisher statistics to calculate the sample mean planes and mean plane uncertainties for the Hilda group and its Hilda, Schubart, and Potomac collisional subfamilies. Although Laplace-Lagrange linear secular theory is considered inapplicable within mean motion resonances, we find that the Laplace plane and the orbital plane of Jupiter are both statistically indistinguishable from the sample mean plane of the Hildas. In future work, we intend to extend this investigation to resonant populations in the Kuiper belt so as to further test the validity of Laplace-Lagrange linear secular theory for the mean planes of resonant populations.
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Solar and Stellar Astrophysics
Detailed TESS-Based Light Curve Modeling and Fundamental Parameter Estimation of 27 W UMa-Type Contact Binaries
Atila Poro, Ahmad Sarostad, Mohammad Davoudi et al. (+30 more)
We performed a comprehensive analysis of 27 short period contact binary systems for which no light curve analysis had previously been reported. Photometric time-series data from the TESS mission were used in this analysis. The observational results were validated using additional TESS sectors, along with complementary photometric observations from the ASAS-SN survey. The photometric light curves of the 27 contact binary systems were analyzed with the BSN application. Model solutions were obtained through iterative fitting followed by MCMC-based refinement to derive reliable system parameters, and starspot configurations were incorporated for seven targets exhibiting O'Connell effect asymmetries. The absolute parameters of the target systems were derived using the empirical parameter relationship between orbital period and semi-major axis. Based on the results of the light curve solutions and the estimated absolute parameters, five of the analyzed systems are identified as A-subtype, while the remaining targets belong to the W-subtype. We analyzed a sample of 484 W UMa contact binaries to identify the physical and orbital parameters that most effectively distinguish A-subtype from W-subtype systems using t-statistics. Three targets exhibited extremely low mass ratios, and their orbital analysis confirmed that they are dynamically stable. The evolutionary states of the systems were examined, showing that lower-mass companions are generally more evolved, while more massive components remain less evolved. The positions of the systems and their
stellar components were compared across four diagrams derived from empirical parameter relationship studies, showing good agreement with the linear fits.
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All authors Atila Poro, Ahmad Sarostad, Mohammad Davoudi, Mahsa Marami, Motaharehalsadat Mohtaram, Mohammadparsa Sharififard, Diana Zadkhosh, Aida Rakian, Alireza Shiri Ahmadabadi, AmirAli Akbarzadeh, Amirali Ashrafpour, Aram Ahmadi, Arshida Amiri, Arshida Goudarzi, Atena Ahmadzadeh, Ehsan Abbasi, Helia Dolati, Kimia Foroush Bastani, Mahdis Derakhshan, MehrAna Mehraban Pour, Nazanin Karimi Shoushtari, Parsa Arezoumand, Reyhaneh Saki, Romina Ozhand, Sama Ghonche Sefidi, Shayan Saeidzadeh, Yeganeh Chaji, Zahra Izadi, Negar Sarlak, Ayda Davoudi, Danial Rahbarmah, Hossein Dehghan, Fahri Alicavus
Solar and Stellar Astrophysics
Dynamics of the coronal magnetic field in the 2022-10-02 X-class flare
Gregory D. Fleishman, Tatyana Kaltman and Sijie Yu
Solar flares are driven by release of free
magnetic energy and often associated with restructurization of the
magnetic field
topology. Yet, observations of evolving
magnetic field in the flaring volume are limited to very few cases including the 2017-09-10 X8.2 limb
flare; thus, a verification of whether a similar
evolution takes place in other
solar flares is needed. Here we report one more, 2022-10-02, X1.1 class
solar flare but seen on disk, whose microwave data permit mapping the
magnetic field over the flaring source and tracking
magnetic field
evolution over the course of the
flare. We found that the coronal
magnetic field shows a prominent decay with the rate up to 10 G s$^{-1}$ in several (above) loop-top locations. The
magnetic field is also confidently measured at the loop legs and the bottom part of the erupting filament. Prominent acceleration of electrons is detected where the
magnetic field decays. We developed 3D models of the
flare, whose
magnetic field shows resemblance and also deviation from the
magnetic field inferred from the microwave data. This study confirms that the coronal
magnetic field decays during the rise phase of the
solar flare. The amount of released
magnetic energy is sufficient to support other components of the
flare energy.
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Astrophysics of Galaxies
Modeling the recent interactions between the Magellanic Clouds and Milky Way
Bethany Garver, David Nidever, Victor Debattista et al. (+1 more)
The Large and Small Magellanic Clouds (LMC and SMC, respectively) are the largest satellite
galaxies of the Milky Way (MW) and their interactions with each other have given rise to multiple
stellar substructures in their periphery as well as the gaseous Magellanic Stream. To better understand the origin of the
stellar substructures and constrain their past orbit, we model the past 2.5 Gyr of the interactions between the MW and the LMC and SMC using N-body simulations. Due to the strong interactions, analytical orbit integrations are insufficient to analyze the past
galaxy orbits accurately. Therefore, we use a genetic
algorithm in combination with N-body simulations to determine the LMC and SMC initial positions and velocities 2.5 Gyr ago that result in the Magellanic Clouds (MCs) arriving near their observed locations and velocities at the current time. After running ~8,000 simulations, our best matching model includes two close interactions between the MCs (940 Myr and 140 Myr ago) and reproduces some observed features of the MCs, including the LMC disc warp, a ring-shaped overdensity in the LMC, the
tidal expansion of the SMC, and a greater distance dispersion on the eastern side of the SMC. The LMC disc warp is caused by the most recent interaction with the SMC, which occurred ~140 Myr before the present. The interaction causes global ripples in the LMC disc with a mean amplitude of 1.3 kpc.
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All authors Bethany Garver, David Nidever, Victor Debattista, Nathan Deg
Solar and Stellar Astrophysics
Wide sdB binaries. I. Orbital and atmospheric parameters
Francisco Molina, Joris Vos, Alexey Bobrick et al. (+1 more)
Long-period binary systems containing a B-type hot subdwarf (sdB) and a main-sequence companion are thought to originate from binary interactions involving stable mass transfer from the red
giant, the progenitor of the sdB, to the MS companion. However, despite the recent progress in modelling their population, some of their observed properties are not entirely understood. Because determining their orbits requires extended campaigns of high-resolution spectroscopic observations, only a limited number of long-period sdB binaries have been studied with completely determined orbital parameters. A sample of 32 wide binary systems containing sdB
stars was selected for the analysis of the radial velocity curves of both companions. The
dataset consisted of high-resolution spectra obtained with the HERMES and UVES spectrographs. The orbital parameters were derived by simultaneously fitting Keplerian orbits to the radial velocities of the sdB and its companion. The atmospheric parameters of the cool companions were determined using the GSSP code, which analyses the master spectra of the systems with a grid of LTE atmospheric models. An additional sample of wide sdB binaries was built up by cross-matching the
Gaia NSS catalogue with catalogues of sdB candidates and spectroscopically confirmed systems reported by Culpan2022A&A catalogues. The outcomes from both samples were compared with existing theoretical models to assess their consistency with current formation and evolutionary scenarios.
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All authors Francisco Molina, Joris Vos, Alexey Bobrick, Maja Vučković
Astrophysics of Galaxies
The CON-quasar stage of IRAS 07251-0248 E
Eduardo González-Alfonso, Miguel Pereira-Santaella, Ismael García-Bernete et al. (+2 more)
ALMA continuum measurements of the local ULIRG IRAS 07251-0248 E at 667$\mu$m reveal an extremely compact (R < 27 pc) and bright ($T_B$ >200 K)
nucleus with an absorbing foreground envelope and a surrounding (R ~ 75 pc) disk or
torus seen nearly face-on. The bright and unresolved
nuclear emission implies large optical depths ($\tau_{667\mu m}$ >0.5, corresponding to $N_H > 10^{25}$ cm^-2) of hot
dust at >500 K. In addition, JWST observations of the source show strong mid-infrared (mid-IR) absorption in the ro-vibrational bands of H2O nu_2=1-0 (5-7 $\mu$m) and of other species including CO, HCN, C2H2, CH4, and CO2, and Herschel/PACS observations exhibit strong and saturated absorption due to OH, H2O, CH^+, and CH. We propose a model in which the unresolved ALMA submillimeter and JWST mid-IR continua trace the same
nuclear source, the former penetrating deep into the
nucleus and the latter probing the
nuclear photosphere. The continuum model, which includes trapping of
photons (the "greenhouse" effect), indicates that the
nuclear ($R_h$ ~ 13 pc) luminosity and luminosity surface density are ~10$^{12}$ Lsun and $\Sigma_{bol}$~ 5e8 Lsun pc^-2, arising from an active
galactic nucleus (AGN) so buried that high-ionization lines are completely obscured. The observed mid-IR gas-phase molecular bands probe outflowing gas with velocities of ~160 km s^-1 and are reproduced with the predicted $T_{dust}$ profile, while the far-IR molecular absorption lines are generated in the surrounding thick disk or
torus with $\tau_{100 \mu m}$~10. We conclude that IRAS 07251-0248 harbors a compact obscured
nucleus (CON) that hides an AGN currently emitting at
quasar luminosity. While the observed
outflow could be driven by radiation pressure, we favor the scenario of a (partially) energy-conserving hot bubble caught in a very early phase of the expulsion of the highly concentrated gas at the
galactic nucleus.
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All authors Eduardo González-Alfonso, Miguel Pereira-Santaella, Ismael García-Bernete, Jacqueline Fischer, Giovanna Speranza
Cosmology and Nongalactic Astrophysics · Cross-listed from gr-qc
Conditions for Gravitational-Wave Echo Suppression in Diffeomorphism-Invariant Nonlocal Quantum Gravity
J. W. Moffat
Gravitational-wave echoes can arise when perturbations are trapped between distinct scattering structures in the effective potential of an ultracompact merger remnant. We examine the conditions under which analytic nonlocal smearing can reduce such signals in a Gaussian-smeared regular compact-object geometry. For configurations possessing a true event horizon, the standard purely ingoing boundary condition excludes an inner echo cavity independently of the ultraviolet completion. For horizonless configurations, smoothness alone does not eliminate echoes. The axial Regge–Wheeler potential can contain a trapping region bounded by an inner centrifugal barrier and an outer potential maximum. We distinguish echoes caused by the global
geometric potential from reflection by an additional localized inner transition layer. If such a layer is smeared over a proper radial length $\ellNL$ and the metric function is approximately constant across it, its tortoise-coordinate width is enhanced by the gravitational
redshift. In the weak-scattering approximation, a Gaussian layer produces the conditional suppression. This result requires a localized weak interaction, slow variation of the background across the layer, and a valid Born approximation. It is not a model-independent exclusion of echoes from smooth horizonless objects. The analysis identifies the
redshift, nonlocal-length, and potential-structure conditions that must be evaluated before gravitational-wave observations can be converted into constraints on analytic nonlocal
quantum gravity.
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Solar and Stellar Astrophysics
Complex hydrogen chemical equilibrium and Gaia low mass problem in cool white dwarfs
Piotr M. Kowalski
Large
Gaia data set shows substantial misfit between models and observation for cool white
dwarfs with $T_{\rm eff}<6000\,\rm K$, resulting in severe underestimation of masses of these
stars. We aim to understand the underlying modelling issues. State of the art atmosphere models have been applied to analyse the
Gaia DR3 sample of white
dwarfs as well as
quantum mechanical calculations to quantify formation and stability of different hydrogen species in the atmospheres of these
stars. We reconcile the models and observations when we artificially suppress formation of $\rm H_3^+$ species, a process which substantially alters the chemical
equilibrium at $T_{\rm eff}<6000\,\rm K$, resulting in an overabundance of free electrons and $\rm H^-$, and strengthening of $\rm H^-$ bound-free absorption. Removing the $\rm H_3^+$ species from chemical
equilibrium consideration makes ionization of hydrogen atoms the main source of free electrons, with the resulting models reproducing well the
Gaia white
dwarfs cooling branch. Because $\rm H_3^+$ must form under the considered conditions, likely it is the overestimation of its partition function and resulting abundance or the formation of $\rm H_3^-$ or another anionic species that suppresses the formation of $\rm H^-$ as a countercharge for $\rm H_3^+$ in current models. Chemical
equilibrium in cool, hydrogen atmospheres white
dwarfs must be reconsidered in respect to the abundance of $\rm H_3^+$ species and presence of unaccounted charge species.
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Cosmology and Nongalactic Astrophysics
The Impact of Galaxy Formation on Galaxy Biasing, and Implications for Primordial non-Gaussianity Constraints
Lucia A. Perez, Shy Genel, Elisabeth Krause et al. (+1 more)
The parameter $f_{\textrm{NL}}$ measures the local non-Gaussianity in the
primordial energy fluctuations of the Universe, with any deviation from $f_{\textrm{NL}}=0$ providing key constraints on inflationary models.
Galaxy clustering is sensitive to $f_{\textrm{NL}}$ at large scale modes and the next generation of
galaxy surveys will approach a statistical error of $\sigma_{f_{\textrm{NL}}}\sim1$. However, the systematic errors on these constraints are dominated by the degeneracy of $f_{\textrm{NL}}$ with the
galaxy bias parameters $b_1$ (
galaxy overdensities caused by mass perturbations) and $b_{\phi}$ (
galaxy overdensities caused by
primordial potential perturbations). It has been shown that the assumed scaling of $b_{\phi}(z)=2\delta_c (b_1(z)-1)$ is not accurate for realistically simulated
galaxies, and depends both on the
galaxy selection and the way that
galaxies are modeled. To address this, we leverage the CAMELS-SAM pipeline to explore how varying parameters of
galaxy formation affects $b_{\phi}$ and $b_1$ for various
galaxy selections. We run separate-universe N-body simulations of $L=205 h^{-1}$ cMpc and $N=1280^3$ to measure $b_{\phi}$, and run 55 unique instances of the Santa Cruz semi-analytic model with varying parameters of
stellar and AGN feedback. We find the behavior and
evolution of a SC-SAM model's
stellar-, SFR- and sSFR- to
halo mass relationships track well with how $b_1$ and $b_{\phi}(b_1)$ change across
redshift and selection for the SC-SAM. We find our variations of the SC-SAM encapsulate the $b_{\phi}$ behavior previously measured in IllustrisTNG, the Munich SAM, and Galacticus.Finally, we identify sSFR selections as particularly robust to varied
galaxy modeling.
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All authors Lucia A. Perez, Shy Genel, Elisabeth Krause, Rachel S. Somerville
High Energy Astrophysical Phenomena
Testing black hole space-times with the S2 star orbit: a Bayesian comparison
César Navarrete, Fernando Vázquez-Chávez, Alejandro Cruz-Osorio et al. (+1 more)
We implement a Markov Chain Monte Carlo method to obtain posterior probability distributions for the parameters of the S2
star orbit around Sagittarius A*, for seven representative non-rotating black hole space-time solutions. In particular, we consider the Schwarzschild, Reissner-Nordström, Janis-Newman-Winicour, and Bardeen black hole space-times from General Relativity, as well as a black hole solution from Einstein-Maxwell-dilaton
gravity, a hairy black hole solution from Horndeski theory, and a Yukawa-like black hole from $f(\mathscr{R})$
gravity. To constrain model parameters, we use the most recent publicly available observational data of the S2
star orbit, namely astrometric measurements, spectroscopic data, and the pericentre advance measured by the
GRAVITY Collaboration. We further perform a consistent
Bayesian comparison of models, calculating the log-Bayes factor of each space-time with respect to the Schwarzschild solution. Our results show that the currently available data indicate no statistically significant preference among the space-times considered. The Bardeen and Yukawa-like models are indistinguishable from Schwarzschild within current uncertainties, while the Reissner-Nordström, Janis-Newman-Winicour, Horndeski and Einstein-Maxwell-dilaton geometries show at most weak and non-decisive strength of evidence under the adopted priors and likelihood choices.
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All authors César Navarrete, Fernando Vázquez-Chávez, Alejandro Cruz-Osorio, Néstor Ortiz
Astrophysics of Galaxies
ASPIRE: The Environments and Dark Matter Halos of Luminous Quasars in the Epoch of Reionization
Feige Wang, Jaclyn B. Champagne, Jiamu Huang et al. (+42 more)
We present a systematic study of the environments of 25 luminous
quasars at $z > 6.5$ from the ASPIRE program. Using JWST/NIRCam WFSS data, we identified 487
galaxies at $5.3 \lesssim z \lesssim 7.0$ exhibiting [OIII] emission. Among these, 122 [OIII] emitters lie within $|\Delta v_{\rm los}| < 1000~{\rm km~s^{-1}}$ of the
quasars, corresponding to a $\sim9.4$-fold enhancement relative to the average
galaxy density at other
redshifts. Furthermore, we identified 16 [CII]-emitting
galaxies at the
quasar redshifts from ALMA mosaic observations. A cross-correlation function (CCF) analysis between
quasars and [OIII]+[CII] emitters yields a cross-correlation length of $r_0^{\rm QG} = 8.68^{+0.51}_{-0.55}~h^{-1}~\mathrm{cMpc}$ and a auto-correlation of $r_0^{\rm{QQ}}=15.76^{+2.48}_{-2.70}~h^{-1}~{\rm cMpc}$, indicating that $z \sim 7$
quasars reside in dark matter
halos with $M_{\rm halo} = 10^{12.27^{+0.21}_{-0.26}}~M_\odot$. Notably, the number of [OIII]-emitting
galaxies at
quasar redshifts varies significantly from field to field, ranging from zero to twenty, highlighting a diverse
quasar environment. Remarkably, seven
quasars trace significant
galaxy overdensities (i.e., protoclusters), with $\delta_{\rm gal} > 5$ within a volume of $V \sim 500~{\rm cMpc^3}$. We also find that $|\Delta v_{\rm los}|$ increases rapidly toward smaller
galaxy-
quasar separations in protocluster fields, consistent with
galaxy kinematics around extremely massive
halos in cosmological simulations. By combining JWST and ALMA data, we reveal the complex and diverse environments of these early
quasars, providing robust evidence that the earliest luminous
quasars are effective tracers of
galaxy overdensities, albeit with substantial field-to-field variation.
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All authors Feige Wang, Jaclyn B. Champagne, Jiamu Huang, Jinyi Yang, Joseph F. Hennawi, Xiaohui Fan, Haowen Zhang, Tiago Costa, Roberto Decarli, Melanie Habouzit, Fengwu Sun, Eduardo Banados, Xiangyu Jin, Koki Kakiichi, Romain A. Meyer, Yunjing Wu, Silvia Belladitta, Laura Blecha, Sarah E. I. Bosman, Zheng Cai, Thomas Connor, Frederick B. Davies, Anna-Christina Eilers, Zoltan Haiman, Hyunsung D. Jun, Mingyu Li, Zihao Li, Weizhe Liu, Alessandro Lupi, Jianwei Lyu, Chiara Mazzucchelli, Masafusa Onoue, Elia Pizzati, Maria Pudoka, Sofia Rojas-Ruiz, Jan-Torge Schindler, Yue Shen, Wei Leong Tee, Benny Trakhtenbrot, Maxime Trebitsch, Marianne Vestergaard, Marta Volonteri, Fabian Walter, Huanian Zhang, Siwei Zou
Cosmology and Nongalactic Astrophysics
Sneh Pandya and Jonathan Blazek
We present diffHOD-IA, a fully differentiable implementation of a
halo occupation distribution (HOD) model that incorporates
galaxy intrinsic
alignments (IA). Motivated by the diffHOD framework, we create a new implementation that extends differentiable
galaxy population modeling to include orientation-dependent statistics crucial for weak gravitational
lensing analyses. Our implementation combines this HOD formulation with an IA model, enabling end-to-end automatic differentiation from HOD and IA parameters through to the
galaxy field. We additionally extend this framework to differentiably model two-point correlation functions, including
galaxy clustering and IA statistics. We validate diffHOD-IA against the reference halotools-IA implementation using the Bolshoi-Planck simulation, demonstrating excellent agreement across both one-point and two-point statistics. We verify the accuracy of gradients computed via automatic differentiation by comparison with finite-difference estimates for both HOD and IA parameters. We present science use cases leveraging gradients in the simulations to recover the IA parameters of a
galaxy field representative of the TNG300 simulation. Finally, we apply diffHOD-IA in a
Hamiltonian Monte Carlo analysis and compare its performance with halotools-IA and a neural-network-based emulator, IAEmu. Unlike emulator-based approaches for statistics, diffHOD-IA provides differentiability at the
galaxy catalog level, enabling integration into field-level inference pipelines and extension to arbitrary summary statistics for next-generation weak-
lensing analyses. Our code is publicly available.
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Astrophysics of Galaxies
Clustering of z~6.6 Quasars and [O III] Emitters Constrains Host Halo Masses and Duty Cycles in 25 ASPIRE Fields
Jiamu Huang, Joseph Hennawi, Elia Pizzati et al. (+21 more)
We use data from the JWST ASPIRE Wide Field Slitless Spectroscopy (WFSS) program to measure the auto-correlation function of [O,iii] emitters at 5.3$<z<$7.0 and the
quasar–[O,iii] emitter cross-correlation around 25 ASPIRE
quasars (6.51$<z<$6.82; $\langle z\rangle=6.6$). We use synthetic source injection to calibrate the selection function, which we combine with the large-volume FLAMINGO-10k simulation (2.8,cGpc box) to construct realistic mock observations. Our simulation-based approach captures nonlinear structure growth and scale-dependent bias on small scales and derives covariance
matrices that include
cosmic variance. The clustering yields correlation lengths of $r_0^{\rm GG}=4.7^{+0.4}{-0.5},h^{-1}$,cMpc for the [O,iii] auto-correlation with fixed slope $\gamma{\rm GG}=1.8$, and $r_0^{\rm QG}=8.7^{+0.8}{-0.9},h^{-1}$,cMpc for the
quasar–[O,iii] cross-correlation with $\gamma{\rm QG}=2.0$. We infer $\log(M_{h,{\rm min}}^{[{\rm O,III}]}/M_\odot)=10.5^{+0.1}{-0.1}$ for [O,iii] emitters and $\log(M{h,{\rm min}}^{\rm QSO}/M_\odot)=12.1^{+0.3}{-0.4}$ for
quasars. These imply duty cycles of $2.5^{+1.0}{-0.8}$,per,cent for [O,iii] emitters and $0.3^{+4.0}{-0.3}$,per,cent for
quasars, corresponding to UV-bright lifetimes of $t{\rm Q}=2.6^{+30}_{-2.5}$,Myr (less than 10,per,cent of a Salpeter $e$-folding time). The results indicate that the observed UV-luminous phase contributes little to total SMBH growth, placing tight constraints on early black-hole formation.
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All authors Jiamu Huang, Joseph Hennawi, Elia Pizzati, Feige Wang, Jinyi Yang, Jaclyn B. Champagne, Xiaohui Fan, Eduardo Bañados, Xiangyu Jin, Koki Kakiichi, Romain A. Meyer, Fengwu Sun, Yunjing Wu, Haowen Zhang, Chiara Mazzucchelli, Anna-Christina Eilers, Maria Pudoka, Huanian Zhang, Jan-Torge Schindler, Matthieu Schaller, Joop Schaye, Ben Snyder, Yi Kang, Silvia Onorato
Astrophysics of Galaxies
Multi-spin stellar velocity maps of the most massive galaxies
Davor Krajnovic, Eric Emsellem, Roland Bacon et al. (+3 more)
(Abridged) We present
stellar kinematics of the MUSE Most Massive
Galaxies (M3G) Survey, comprising 25
galaxies brighter than -25.7 mag in the Ks-band and
stellar mass above ~6x10^11 Msun.
Galaxies are divided between the brightest cluster
galaxies (BCGs) and lower-ranked (in brightness)
galaxies (non-BCGs) in three rich
galaxy clusters within the core of the Shapley super cluster. We find several velocity maps with rich kinematic structure, including multiple
spin reversals within the region encompassing central two effective radii, typically associated with BCGs. The majority of BCGs show rotation around the major-axis, at least in one of the visible velocity components. These kinematic structures are possible only if
galaxies have non-axisymmetric shapes and contain several orbital families with both prograde and retrograde rotations. There are six fast rotators in the M3G sample, all among non-BCGs, and typically ranked below the 3rd brightest
galaxy. Based on the properties of the h3 Gauss-Hermite moment, fast rotation can be linked to the dominance of prograde rotating short-axis tubes in the orbital distribution. Slow rotators are BCGs or the second and sometimes third brightest
galaxies, indicating that the
galaxy mass (brightness) is not the only driver of low
spin, but that the location within the local environment also plays a role. Slow rotators, as evidenced from their multi-
spin velocity maps, require more complex orbital structures. Furthermore, some BCGs show kinematic evidence for a secondary component at larger radii, likely not in
equilibrium with the main
galaxy and possibly made of
stars accreted from other cluster
galaxies. Multi-
spin velocity maps, low angular momentum and additional kinematic components highlight the difference in the evolutionary histories of BCGs (including 2nd ranked
galaxies) and non-BCGs.
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All authors Davor Krajnovic, Eric Emsellem, Roland Bacon, Leindert A. Boogaard, Peter M. Weilbacher, Lutz Wisotzki
Astrophysics of Galaxies
Abundant hydrocarbons in a buried galactic nucleus with signs of carbonaceous grain and polycyclic aromatic hydrocarbon processing
I. García-Bernete, M. Pereira-Santaella, E. González-Alfonso et al. (+5 more)
Hydrocarbons play a key role in shaping the chemistry of the interstellar medium (ISM), but their enrichment and relationship with carbonaceous grains and polycyclic aromatic hydrocarbons (PAHs) still lack clear observational constraints. We report JWST NIRSpec+MIRI/MRS infrared (IR; 3-28 micron) observations of the local ultra-luminous IR
galaxy (ULIRG) IRAS 07251-0248, revealing the extragalactic detection of small gas-phase hydrocarbons such as benzene (C$_6$H$_6$), triacetylene (C$_6$H$_2$), diacetylene (C$_4$H$_2$), acetylene (C$_2$H$_2$), methane (CH$_4$), and methyl radical (CH$_3$) as well as deep amorphous C-H absorptions in the solid phase. The unexpectedly high abundance of these molecules indicates an extremely rich hydrocarbon chemistry, not explained by high-temperature gas-phase chemistry, ice desorption or oxygen depletion. Instead, the most plausible explanation is the erosion and fragmentation of carbonaceous grains and PAHs. This scenario is supported by the correlation between the abundance of one of their main fragmentation products, C$_2$H$_2$, and
cosmic ray (CR) ionization rate for a sample of local ULIRGs. These hydrocarbons are outflowing at $\sim$160 km/s, which may represent a potential formation pathway for hydrogenated amorphous grains. Our results suggest that IRAS 07251-0248 might not be unique but represents an extreme example of the commonly rich hydrocarbon chemistry prevalent in deeply obscured
galactic nuclei.
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All authors I. García-Bernete, M. Pereira-Santaella, E. González-Alfonso, M. Agúndez, D. Rigopoulou, F.R. Donnan, G. Speranza, N. Thatte
Cosmology and Nongalactic Astrophysics
Establishing a relationship between the cosmological 21 cm power spectrum and interferometric closure phases
Pascal M. Keller, Bojan Nikolic and Nithyanandan Thyagarajan
Measurements of the
cosmic 21 cm signal need to achieve a high dynamic range to isolate it from bright foreground emissions. Calibration inaccuracies can compromise the spectral fidelity of the smooth foreground continuum, thereby limiting the dynamic range and potentially precluding the detection of the
cosmic line signal. In light of this challenge, recent work has proposed using the calibration-independent closure phase to search for the spectral fluctuations of the
cosmic 21 cm signal. However, so far there has been only a heuristic understanding of how closure phases map to the cosmological 21 cm power spectrum. This work aims to establish a more accurate mathematical relationship between closure phases and the cosmological power spectrum of the background line signal. Building on previous work, we treat the
cosmic signal component as a perturbation to the closure phase and use a delay spectrum approach to estimate its power. We establish the relationship between this estimate and the cosmological power spectrum using standard
Fourier transform techniques and validate it using simulated HERA observations. We find that, statistically, the power spectrum estimate from closure phases is approximately equal to the cosmological power spectrum convolved with a foreground-dependent window function, provided that the signal-to-foreground ratio is small. Compared with standard approaches, the foreground dependence of the window function results in an increased amount of mode-mixing and a more pronounced proliferation of foreground power along the line-of-sight dimension of the cylindrical power spectrum. These effects can be mitigated by flagging instances where the window function is broad. Crucial to gaining the necessary sensitivity, this mapping will allow us to average the measurements of closure triads of different shapes based on their imprint in cylindrical
Fourier space.
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