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At least 631 records · Page 35

MaNGA galaxy properties – II. A detailed comparison of observed and simulated spiral galaxy scaling relations

ABSTRACT We present a catalogue of dynamical properties for 2368 late-type galaxies from the MaNGA survey. The latter complements the catalogue of photometric properties for the same sample based on deep optical dark energy sky instrument legacy imaging survey (DESI) photometry processed with autoprof . Rotation curves (RCs), extracted by model-fitting H α velocity maps from the MaNGA Data Analysis Pipeline, extend out to 1.4 (1.9) Re for the primary (secondary) MaNGA samples, respectively. The RCs and ancillary MaNGA Pipe3D data products were used to construct various fundamental galaxy scaling relations that are also compared uniformly with similar relations from numerical investigation of a hundred astrophysical object (NIHAO) zoom-in simulations. Simulated NIHAO galaxies were found to broadly reproduce the observed MaNGA galaxy population for $\log (M_*/{\rm {\rm M}_{\odot })\, \gt\, 8.5}$. Some discrepancies remain, such as those pertaining to central stellar densities and the diversity of RCs due to strong feedback schemes. Also presented are spatially resolved scatters for the velocity-size-stellar mass (VRM*) structural relations using MaNGA and NIHAO samples. The scatter for these relations in the galaxian interiors is a consequence of the diversity of inner RC shapes, while scatter in the outskirts is dictated by the large range of stellar surface densities, which is itself driven by sporadic star formation. The detailed, spatially resolved scatter analysis highlights the complex interplay between local and global astrophysical processes and provides a strong constraint to numerical simulations.

Astronomy & Astrophysics↗

The separate effect of halo mass and stellar mass on the evolution of massive disc galaxies

ABSTRACT We analyse a sample of massive disc galaxies selected from the fourth-generation Sloan Digital Sky Survey/Mapping Nearby Galaxies at Apache Point Observatory survey to investigate how the evolution of these galaxies depends on their stellar and halo masses. We applied a semi-analytic spectral fitting approach to the data from different regions in the galaxies to derive several of their key physical properties. From the best-fitting model results, together with direct observables such as morphology, colour, and the Mgb/〈Fe〉 index ratio measured within 1Re, we find that for central galaxies both their stellar and halo masses have a significant influence in their evolution. For a given halo mass, galaxies with higher stellar mass accumulate their stellar mass and become chemically enriched earlier than those with smaller stellar mass. Furthermore, at a given stellar mass, galaxies living in more massive haloes have longer star formation time-scales and are delayed in becoming chemically enriched. In contrast, the evolution of massive satellite galaxies is mostly determined by their stellar mass. The results indicate that both the assembled halo mass and the halo assembly history impact the evolution of central galaxies. Our spatially resolved analysis indicates that only the galaxy properties in the central region (0.0–0.5Re) show the dependencies described above. This fact supports a halo-driven formation scenario since the galaxies’ central regions are more likely to contain old stars formed along with the halo itself, keeping a memory of the halo formation process.

Zhou, Shuang (ORCID:0000000289996814)↗

Large-scale clustering of Lymanα emission intensity from SDSS/BOSS

Here we present a tentative detection of the large-scale structure of Ly α emission in the Universe at redshifts z = 2–3.5 by measuring the cross-correlation of Ly α surface brightness with quasars in Sloan Digital Sky Survey/Baryon Oscillation Spectroscopic Survey. We use a million spectra targeting luminous red galaxies at z < 0.8, after subtracting a best-fitting model galaxy spectrum from each one, as an estimate of the high-redshift Ly α surface brightness. The quasar–Ly α emission cross-correlation is detected on scales 1 ~ 15h ₋1 Mpc, with shape consistent with a ΛCDM model with Ω m =0.30± 0.10 0.07 . The predicted amplitude of this cross- correlation is proportional to the product of the mean Lyα surface brightness, {μ α }, the amplitude of mass density fluctuations, and the quasar and Lyα emission bias factors. Using published cosmological observations to constrain the amplitude of mass fluctuations and the quasar bias factor, we infer the value of the product {μ α } (b α /3) = (3.9±0.9)×10 ₋21 erg s ₋1 cm ₋2 °A ₋1 arcsec ₋2 , where b α is the Lyα emission linear bias factor. If the dominant sources of Lyα emission we measure are star forming galaxies, we infer a total mean star formation rate density of ρSFR = (0.28 ± 0.07)(3/b α ) yr ₋1 Mpc ₋3 at z = 2 ₋ 3.5. For b α = 3, this value is a factor of 21 ₋ 35 above previous estimates relying on individually detected Lyα emitters, although it is consistent with the total star-formation density derived from dust-corrected, continuum UV surveys. Our observations therefore imply that 97% of the Lyα emission in the Universe at these redshifts is undetected in previous surveys of Lyα emitters. Our detected Lyα emission is also much greater, by at least an order of magnitude, than that measured from stacking analyses of faint halos surrounding previously detected Lyα emitters, but we speculate that it arises from similar low surface brightness Lyα halos surrounding all luminous star-forming galaxies. We also detect a redshift space anisotropy of the quasar-Lyα emission cross-correlation, finding evidence at the 3.0σ level that it is radially elongated, contrary to the prediction for linear gravitational evolution, but consistent with distortions caused by radiative-transfer effects, as predicted by Zheng et al. (2011). Lastly, our measurements represent the first application of the intensity mapping technique to optical observations.

79 ASTRONOMY AND ASTROPHYSICS↗

Dark Energy Survey year 1 results: the relationship between mass and light around cosmic voids

What are the mass and galaxy profiles of cosmic voids? In this paper, we use two methods to extract voids in the Dark Energy Survey (DES) Year 1 redMaGiC galaxy sample to address this question. We use either 2D slices in projection, or the 3D distribution of galaxies based on photometric redshifts to identify voids. For the mass profile, we measure the tangential shear profiles of background galaxies to infer the excess surface mass density. The signal-to-noise ratio for our lensing measurement ranges between 10.7 and 14.0 for the two void samples. We infer their 3D density profiles by fitting models based on N-body simulations and find good agreement for void radii in the range 15–85 Mpc. Comparison with their galaxy profiles then allows us to test the relation between mass and light at the 10 per cent level, the most stringent test to date. We find very similar shapes for the two profiles, consistent with a linear relationship between mass and light both within and outside the void radius. We validate our analysis with the help of simulated mock catalogues and estimate the impact of photometric redshift uncertainties on the measurement. Our methodology can be used for cosmological applications, including tests of gravity with voids. Finally, this is especially promising when the lensing profiles are combined with spectroscopic measurements of void dynamics via redshift-space distortions.

79 ASTRONOMY AND ASTROPHYSICS↗

Allosteric autoregulation of DNA binding via a DNA-mimicking protein domain: a biophysical study of ZNF410–DNA interaction using small angle X-ray scattering

ZNF410 is a highly-conserved transcription factor, remarkable in that it recognizes a 15-base pair DNA element but has just a single responsive target gene in mammalian erythroid cells. ZNF410 includes a tandem array of five zinc-fingers (ZFs), surrounded by uncharacterized N- and C-terminal regions. Unexpectedly, full-length ZNF410 has reduced DNA binding affinity, compared to that of the isolated DNA binding ZF array, both in vitro and in cells. AlphaFold predicts a partially-folded N-terminal subdomain that includes a 30-residue long helix, preceded by a hairpin loop rich in acidic (aspartate/glutamate) and serine/threonine residues. This hairpin loop is predicted by AlphaFold to lie against the DNA binding interface of the ZF array. In solution, ZNF410 is a monomer and binds to DNA with 1:1 stoichiometry. Surprisingly, the single best-fit model for the experimental small angle X-ray scattering profile, in the absence of DNA, is the original AlphaFold model with the N-terminal long-helix and the hairpin loop occupying the ZF DNA binding surface. For DNA binding, the hairpin loop presumably must be displaced. After combining biophysical, biochemical, bioinformatic and artificial intelligence-based AlphaFold analyses, we suggest that the hairpin loop mimics the structure and electrostatics of DNA, and provides an additional mechanism, supplementary to sequence specificity, of regulating ZNF410 DNA binding.

59 BASIC BIOLOGICAL SCIENCES↗

Resonant scattering at the center of the galaxy cluster PKS 0745-191 with XRISM

We report evidence of the resonant scattering effect at the center of the galaxy cluster PKS 0745-191 with XRISM. We analyzed XRISM/Resolve commissioning-phase observations of the distant cluster PKS 0745-191 ($z = 0.103$) with a $54$ ks exposure. The gain drift was corrected using the onboard modulated X-ray source (MXS), and spectra were extracted from all the pixels that were well illuminated by MXS, the core region (four central pixels, $\sim$100 kpc), and the surrounding region. A single-temperature collisional ionization equilibrium (CIE) model fits the full field-of-view spectrum with $kT \approx 6$ keV and a turbulent velocity of ${\approx}120$ km s$^{-1}$. From the core ($r < 50$ kpc) spectrum, we detected a ${\approx}22\%$ suppression of the Fe xxv He$\alpha$ resonance (w) line relative to the CIE prediction. We performed a Monte Carlo simulation to calculate the resonant scattering (RS) effect using radial profiles from Chandra data. The RS-inferred turbulence agrees with that by Resolve line-broadening, demonstrating that RS provides an independent and consistent constraint on ICM turbulence. These results highlight XRISM/Resolve’s potential for turbulence studies in galaxy clusters.

Astronomy and AstroPhysics↗

The Role of Extracellular Fluid in Biokinetic Modeling

Here, the pharmacokinetic equations of Pierson et al. describing the behavior of bromide in rat provide a general approach to the modeling of extracellular fluid (ECF). The movement of material into ECF spaces is rapid and is completely characterized by tissue volumes and vascular flow rates to and from a tissue, the volumes of the tissue, and the ECF associated with the tissue. Early-time measurements are needed to characterize ECF. Measurements of DTPA disappearance from plasma by Wedeking et al. are discussed as an example of such measurements. In any biokinetic model, the fastest transfer rates are not determinable with the usual datasets, and if determined empirically, these rates will have very large and highly correlated uncertainties, so particular values of these rates, even though the model fits the available data, are not significant. A pharmacokinetic front-end provides values for these fast rates. An example of such a front-end for a 200–g rat is given.

61 RADIATION PROTECTION AND DOSIMETRY↗

Refining the two-band model for highly compensated semimetals using thermoelectric coefficients

In studying compensated semimetals, the two-band model has proven extremely useful in capturing electrical conductivity under magnetic field, as a function of density and mobility of electronlike and holelike carriers. However, it rarely offers practical insight into magnetothermoelectric properties. Here, in this work, we report the field dependence of thermoelectric (TE) coefficients in a highly compensated semimetal NbSb 2 , where we find the Seebeck (𝑆 𝑥⁢𝑥 ) and Nernst (𝑆 𝑥⁢𝑦 ) coefficients increase quadratically and linearly with applied magnetic field, respectively. Such field dependence was predicted in previous work that studied a system of two parabolic bands, within semiclassical Boltzmann transport theory when the following two conditions are simultaneously met: 𝜔 𝑐 ⁢𝜏 ≫ 1 and tan ⁡𝜃 𝐻 ≪ 1, where 𝜔 𝑐 and 𝜏 refer to the cyclotron frequency and relaxation time, respectively, and 𝜃 𝐻 is the Hall angle. Under these conditions, we find the field dependence of the TE coefficients directly provides a relation between the electronlike (𝑛 𝑒 ) and holelike (𝑛 ℎ ) carrier densities, which in turn can be used to refine two-band model fitting. With this, we find the compensation factor ($\frac{|Δ⁢𝑛|}{𝑛_{𝑒}}$, where Δ⁢𝑛 = 𝑛 𝑒 −𝑛 ℎ ) of NbSb 2 is two orders of magnitude smaller than what was found in unrestricted fitting, resulting in a larger saturation-field scale for magnetoresistance. Within the same framework of the semiclassical theory, we also deduce that the thermoelectric Hall angle tan⁡ 𝜃 𝛾 = $\frac{𝑆_{𝑥⁢𝑦}}{𝑆_{𝑥⁢𝑥}}$ can be expressed as ($\frac{Δ⁢𝑛}{𝑛_{𝑒}}$ ×𝜔 𝑐 ⁢𝜏) −1 , which serves as a parameter to predict the degree of compensation. Our findings offer crucial insights into identifying empirical conditions for field-induced enhancement of TE performance and into engineering-efficient thermoelectric devices based on semimetallic materials.

electrical conductivity↗

Observing pre-edge K -shell resonances in Kr, Xe, and XeF 2

The 1s→np Rydberg transitions below the 1s ionization thresholds of Kr and Xe are obscured in x-ray absorption spectra due to core-hole lifetime broadening. However, the np spectator electrons associated with those resonances can affect the core-hole decay spectra. We report on ion charge-state distributions of Kr and Xe measured in coincidence with KL 2,3 (K α1,2 ), KM 2,3 (Kβ 1,3 ), and KN 2,3 (Kβ 2 ) x-ray fluorescence as the incident x-ray energy is scanned through pre-edge resonances and ionization thresholds. The coincidence measurements select vacancy cascades that begin with a radiative transition that transfers 1s holes to the 2p, 3p, and 4p shells followed by emission of Auger electrons. We observe shifts of ion yields from higher to lower charge states that we attribute to np spectator electrons. For the special case of Kr 1+ that is produced in coincidence with Kβ 2 x rays, the ion yield decreases in the pre-edge region. This is attributed to production of neutral, metastable Kr 4p –1 np states that reduce the Kr 1+ yield. Model fits to the x-ray absorption spectra are presented to show the lifetime broadened pre-edge resonances and ionization thresholds. High-level relativistic coupled-cluster calculations that treat relativistic, electron correlation, and wave function relaxation effects on the same footing obtain agreement with the experimental 1s ionization energies of Kr and Xe to <2 eV. The Xe K-edge x-ray absorption spectrum and ion charge-state distributions of XeF2 were also recorded. Excitation of the 7σ u lowest unoccupied molecular orbital (LUMO) in XeF 2 is observed in the pre-edge region. Our ab initio calculations find that the 6p z Rydberg state is strongly perturbed by the presence of the 7σu LUMO. A fit to the measured LUMO, 6p x , 6p y , 6p z Rydberg states, and ionization threshold is guided by the relativistic coupled-cluster calculations. The F ligands modify the valence electron charge distribution and result in a ~2.3 eV chemical shift of the Xe 1s ionization energy relative to atomic Xe. Xe 1s –1 core-hole decay in XeF 2 results in ionization of the F ligands and energetic fragmentation into atomic ions. Ion charge-state spectra of XeF 2 were recorded in coincidence with x-ray fluorescence for excitation on the LUMO resonance and above the Xe 1s ionization threshold. For the ion time of flight spectra recorded on the LUMO resonance, the F q+ (q = 1–4) peaks are split into two peaks along the linear polarization direction of the incident x-ray beam. This effect is attributed to spatial alignment of XeF 2 molecules by resonant x-ray absorption, and the peak splittings are used to measure the F ion fragmentation energies following Kα 1,2 , Kβ 1,3 , and Kβ 2 x-ray fluorescence. Here, we observe variations of the F ion charge state yields and fragmentation energies for the three fluorescence pathways that leave the molecule in different outer-shell hole states.

74 ATOMIC AND MOLECULAR PHYSICS↗

Quantum-accurate spectral neighbor analysis potential models for Ni-Mo binary alloys and fcc metals

In recent years, efficient interatomic potentials approaching the accuracy of density functional theory (DFT) calculations have been developed using rigorous atomic descriptors satisfying strict invariances, for example, for translation, rotation, permutation of homonuclear atoms, among others. In this work, we generalize the spectral neighbor analysis potential (SNAP) model to bcc-fcc binary alloy systems. We demonstrate that machine-learned SNAP models can yield significant improvements even over the well-established high-performing embedded atom method (EAM) and modified EAM potentials for fcc Cu and Ni. We also report on the development of a SNAP model for the fcc Ni-bcc Mo binary system by machine learning a carefully constructed large computed data set of elemental and intermetallic compounds. We demonstrate that this binary Ni-Mo SNAP model can achieve excellent agreement with experiments in the prediction of a Ni-Mo phase diagram as well as near-DFT accuracy in the prediction of many key properties, such as elastic constants, formation energies, melting points, etc., across the entire binary composition range. In contrast, the existing Ni-Mo EAM has significant errors in the prediction of the phase diagram and completely fails in binary compounds. Lastly, this paper provides a systematic model development process for multicomponent alloy systems, including an efficient procedure to optimize the hyperparameters in the model fitting, and paves the way for long-time large-scale simulations of such systems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Semiclassical shell-structure micro-macroscopic approach for the level density

Level density ρ(E,A) is derived for a one-component nucleon system with a given energy E and particle number A within the mean-field semiclassical periodic-orbit theory beyond the saddle-point method of the Fermi gas model. We obtain ρ∝I ν (S)/S ν , with I ν (S) being the modified Bessel function of the entropy S. Within the micro-macro-canonical approximation (MMA), for a small thermal excitation energy U, with respect to rotational excitations E rot , one obtains ν = 3/2 for ρ(E,A). In the case of excitation energy U larger than E rot but smaller than the neutron separation energy, one finds a larger value of ν = 5/2. A role of the fixed spin variables for rotating nuclei is discussed. The MMA level density ρ reaches the well-known grand-canonical ensemble limit (Fermi gas asymptote) for large S related to large excitation energies, and also reaches the finite micro-canonical limit for small combinatorial entropy S at low excitation energies (the constant “temperature” model). Fitting the ρ(E,A) of the MMA to the experimental data for low excitation energies, taking into account shell and, qualitatively, pairing effects, one obtains for the inverse level density parameter K a value which differs essentially from that parameter derived from data on neutron resonances.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Measurement of the higher-order anisotropic flow coefficients for identified hadrons in Au + Au collisions at s N N = 200 GeV

In this paper, measurements of the anisotropic flow coefficients v 2 {Ψ 2 }, v 3 {Ψ 3 }, v 4 {Ψ 4 }, and v 4 {Ψ 2 } for identified particles (π ± , K ± , and p + ¯p) at midrapidity, obtained relative to the event planes Ψ m at forward rapidities in Au + Au collisions at s N N = 200 GeV , are presented as a function of collision centrality and particle transverse momenta p T . The v n coefficients show characteristic patterns consistent with hydrodynamical expansion of the matter produced in the collisions. For each harmonic n, a modified valence quark-number N q scaling [plotting v n {Ψ m }/(N q ) n/2 versus transverse kinetic energies (KE T )/N q ] is observed to yield a single curve for all the measured particle species for a broad range of KE T . A simultaneous blast-wave model fit to the observed v n {Ψ m }(p T ) coefficients and published particle spectra identifies radial flow anisotropies ρ n {Ψ m } and spatial eccentricities s n {Ψ m } at freeze-out. Finally, these are generally smaller than the initial-state participant-plane geometric eccentricities ε n {Ψ PP m } as also observed in the final eccentricity from quantum interferometry measurements with respect to the event plane.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Modeling intrinsic galaxy alignment in the MICE simulation

The intrinsic alignment (IA) of galaxies is potentially a major limitation in deriving cosmological constraints from weak lensing surveys. In order to investigate this effect, we assign intrinsic shapes and orientations to galaxies in the light-cone output of the MICE simulation, spanning ~ 5000 deg 2 and reaching redshift Z = 1.4. This assignment is based on a semianalytic IA model that uses photometric properties of galaxies as well as the spin and shape of their host halos. Advancing on previous work, we include more realistic distributions of galaxy shapes and a luminosity-dependent galaxy-halo alignment. The IA model parameters are calibrated against COSMOS and BOSS LOWZ observations. The null detection of IA in observations of blue galaxies is accounted for by setting random orientations for these objects. We compare the two-point alignment statistics measured in the simulation against predictions from the analytical IA models NLA and TATT over a wide range of scales, redshifts, and luminosities for red and blue galaxies separately. We find that both models fit the measurements well at scales above 8h -1 Mpc, while TATT outperforms NLA at smaller scales. The IA parameters derived from our fits are in broad agreement with various observational constraints from red galaxies. Finally, we build a realistic source sample, mimicking DES Year 3 observations and use it to predict the IA contamination to the observed shear statistics. We find this prediction to be within the measurement uncertainty, which might be a consequence of the random alignment of blue galaxies in the simulation.

79 ASTRONOMY AND ASTROPHYSICS↗

Measurement of lepton universality parameters in B + → K + ℓ + ℓ – and B 0 → K* 0 ℓ + ℓ – decays

A simultaneous analysis of the B + → K + ℓ + ℓ – and B 0 → K* 0 ℓ + ℓ – decays is performed to test muon-electron universality in two ranges of the square of the dilepton invariant mass, q 2 . The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb –1 . A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes. Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model. Each of the four lepton universality measurements reported is either the first in the given q 2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.

79 ASTRONOMY AND ASTROPHYSICS↗

Lattice B -field correlators for heavy quarks

We analyze the color-magnetic (or “ B ”) field two-point function that encodes the finite-mass correction to the heavy-quark momentum-diffusion coefficient. The simulations are done on fine isotropic lattices in the quenched approximation at 1.5 T c , using a range of gradient flow times for noise suppression and operator renormalization. The continuum extrapolation is performed at fixed flow time followed by a second extrapolation to zero flow time. Perturbative calculations to next-to-leading order of this correlation function, matching gradient-flowed correlators to MS ¯ , are used to resolve nontrivial renormalization issues. We perform a spectral reconstruction based on perturbative model fits to estimate the coefficient κ B of the finite-mass correction to the heavy-quark momentum-diffusion coefficient. The approach we present here yields high-precision data for the correlator with all renormalization issues incorporated at next-to-leading order and is also applicable for actions with dynamical fermions. Published by the American Physical Society 2024

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Strangeness-correlations on the pseudocritical line in ( 2 + 1 )-flavor QCD

We present some lattice QCD results on first ( χ 1 i ) and second ( χ 2 i ) cumulants of and correlations ( χ 11 i j ) among net baryon-number ( B ), strangeness ( S ) and electric charge ( Q ) along the pseudocritical line [ T p c ( μ B ) ] in the temperature ( T )–baryon chemical potential ( μ B ) phase diagram of ( 2 + 1 )-flavor QCD. We point out that violations of sum rules among second order cumulants, which hold in the isospin symmetric limit of vanishing electric charge chemical potential, are small along the T p c ( μ B ) for the entire range of μ B covered in the RHIC beam energy scan. For the strangeness neutral matter produced in heavy-ion collisions this leads to a close relation between χ 11 B S and χ 11 Q S . We compare lattice QCD results for χ 11 B S / χ 2 S along the T p c ( μ B ) line with preliminary experimental measurements of χ 11 B S / χ 2 S for collision energies 7.7 GeV ≤ s N N ≤ 62.4 GeV . While we find good agreements for s N N ≥ 39 GeV , differences are sizeable at smaller values of s N N . Moreover, we compare lattice QCD results for the ratio of the strangeness ( μ S ) to baryon ( μ B ) chemical potentials, which define a strangeness neutral system with fixed electric charge to baryon number density, with experimental results obtained by the STAR collaboration for μ S / μ B using strange baryon yields on the freeze-out line. Finally, we determine the baryon chemical potential at the freeze-out ( μ B f ) by comparing χ 1 B / χ 2 B along the T p c ( μ B ) with the experimentally measured net-proton cumulants χ 1 p / χ 2 p . We find that { μ B f , T p c ( μ B f ) } are consistent with the freeze-out parameters of the statistical-model fits to experimentally measured hadron yields for s N N ≥ 11.5 GeV . Published by the American Physical Society 2024

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗