Context. Disc galaxies exhibit radial metallicity gradients in both their stellar and gaseous components. The star-forming gas (SFG) in H II regions and young stars (YSs) trace the recent evolutionary history of the galaxy. By analysing their metallicity gradients in tandem, we can shed light on the different physical processes that interact in a complex manner, modifying the distribution of chemical elements in the discs, thereby influencing the chemical evolution of galaxies.
Aims. We aim to assess the extent to which the joint analysis of metallicity gradient alignment in YSs and SFG can constrain the recent evolutionary history of galaxies.
Methods. Using the high-resolution run of the EAGLE project, we derived radial, azimuthally averaged oxygen abundance profiles for YSs (age < 2 Gyr) and SFG and measured their gradients as the slopes of linear fits to these profiles. We classified galaxies into four groups based on the signs (N for negative and P for positive) of the slopes: NN, NP, PP, and PN (the first letter is for YSs and the second for SFG).
Results. We found that galaxies with NN, NP, PP, and PN combinations of metallicity profiles reflect different evolutionary paths over the past ∼2 Gyr. NN galaxies exhibit sustained inside-out growth accompanied by high star formation efficiency, whereas NP and PP systems show evidence of recent or ongoing feedback-driven disruption, with PP galaxies likely being predominantly shaped by supernova feedback. PN galaxies, by contrast, show evidence of past violent events followed by gradient recovery, highlighting the interplay between inflows, feedback, and gas cooling in shaping metallicity distributions.
Conclusions. The degree of alignment between the stellar and gas metallicity gradients provides a way to time the occurrence of significant events in the evolutionary history of galaxies, which contribute through a combination of gas inflows, star formation triggering, and metal mixing. They could also serve as probes of sub-grid physics when observations provide suitable comparison datasets.
Daniel J. D’Orazio, Christopher Tiede, Lorenz Zwick
et al.
If supermassive black hole binaries (SMBHBs) are driven together by gas disks in galactic nuclei, then a surrounding nuclear star cluster or in situ star formation should deliver stars to the disk plane. Migration through the circumbinary disk will quickly bring stars to the edge of a low-density cavity cleared by the binary, where the stellar orbit becomes trapped and locked with the binary decay. Here we explore the scenario where the trapped stellar orbit decays with the binary until the binary tidally strips the star in a runaway process. For Sun-like stars, this occurs preferentially for 10 ^4 –10 ^6 M _⊙ SMBHBs, as the SMBHB enters the LISA band. We estimate that the runaway stripping process will generate Eddington-level X-ray flares repeating on hours-to-days timescales and lasting for decades. The flaring timescales and energetics of these circumbinary disk tidal disruption events (CBD-TDEs) match well with the recently discovered quasiperiodic eruptions. However, the inferred rates of the two phenomena are in tension, unless low-mass SMBHB mergers are more common than expected. For less-dense stars, stripping begins earlier in the SMBHB inspiral, has longer repetition times, lasts longer, is dimmer, and can occur for more-massive SMBHBs. Whether CBD-TDEs are a known or a yet-undiscovered class of repeating nuclear transients, they could provide a new probe of the elusive SMBH mergers in low mass/dwarf galaxies, which lie in the sweet-spot of the LISA sensitivity.
Michael Buehlmann, Lukas Winkler, Oliver Hahn
et al.
We present the online service cosmICweb (**COSM**ological **I**nitial **C**onditions on the **WEB**) - the first database and web interface to store, analyze, and disseminate initial conditions for zoom simulations of objects forming in cosmological simulations: from galaxy clusters to galaxies and more. Specifically, we store compressed information about the Lagrangian proto-halo patches for all objects in a typical simulation merger tree along with properties of the halo/galaxy across cosmic time. This enables a convenient web-based selection of the desired zoom region for an object fitting user-specified selection criteria. The information about the region can then be used with the MUSIC code to generate the zoom ICs for the simulation. In addition to some other simulations, we currently support all objects in the EAGLE simulation database, so that for example the Auriga simulations are easily reproduced, which we demonstrate explicitly. The framework is extensible to include other simulations through an API that can be added to an existing database structure and with which cosmICweb can then be interfaced. We make the web portal and database publicly available to the community.
The 21 cm emission from neutral hydrogen surveys holds great potential as a valuable method for exploring the large-scale structure (LSS) of the Universe. In this paper, we forecast for the cross-correlation between the thermal Sunyaev–Zel’dovich (SZ) fluctuations as probed by the Planck satellite and fluctuations in the H i brightness temperature as probed by the ground-based Five-hundred-meter Aperture Spherical Telescope to trace the connection between galaxy clusters and the H i LSS. Assuming that the measurement is limited by instrumental noise rather than by foreground, we estimate the potential detectability of the cross-correlation signal and the improvement in the measurement of the H i cosmic density, the hydrostatic mass bias parameter, and the universal pressure profile parameters. We obtain a constraint on the cosmic neutral hydrogen density parameter significantly to σ (Ω _H I ) = 1.0 × 10 ^−6 . We also find that the average halo masses contributing to the H i − y cross-power spectrum in the one-halo regime is ∼1.5 × 10 ^14 M _⊙ . Our results also show that the H i –SZ cross-correlation has great potential to probe the distribution of neutral hydrogen (H i ) within halos at low redshift.
High purity germanium detectors play an increasingly significant role in particle physics and astrophysics, particularly in low-background radiation measurement experiments, due to their exceptional energy resolution, high detection efficiency. These detectors are especially critical in the search for rare events, such as neutrinoless double-beta decay (0vββ) and direct detection of dark matter, as they operate effectively under extremely low-background conditions. To fully leverage the advantages of HPGe detectors, a specifically tailored front-end readout system was required to minimize the contribution of electronic noise from the system itself. This noise minimization is critical to ensure that weak event signals from inside the detector are not obscured by the system’s inherent noise. In this paper, the design of a multi-channel, low-noise charge-sensitive amplifier (CSA) optimized for use with coaxial HPGe detectors was proposed, particularly those with large input capacitance. Large-capacitance detectors tend to introduce significant input noise, which degrades the overall energy resolution of the system. Therefore, higher standards are necessary for the noise performance of front-end electronics in such systems to preserve the excellent resolution that HPGe detectors can achieve. In multi-stage amplification systems, the noise performance is primarily influenced by the first amplification stage, where the noise characteristics of the input transistor play a crucial role. To address this, the input transistor was designed using an optimized noise model, iterative simulations, and a specially engineered layout structure to ensure low noise. However, larger transistor sizes can lead to gate leakage currents, which can alter the baseline of the amplifier output. To address this issue, a low-noise CSA circuit with a feedback resistor module for leakage current compensation was developed. This resistor feedback module mitigates sensitivity to power supply variations, temperature changes, and process deviations, and can compensate for leakage currents up to several micro amperes. Importantly, the circuit is self-biased, eliminating the need for external bias to adjust the feedback resistance value. The proposed amplifier demonstrated a rise time of less than 50 ns when used with a detector capacitance of 10 pF, and no oscillations were observed under these conditions. At low temperatures, the amplifier exhibits outstanding noise performance, with a noise level as low as 5.6 electrons. Additionally, it provides an output conversion gain of 5 mV/fC, a linearity deviation of only 0.15%, and a low static power consumption of 12.5 milliwatts. The performance achieved is sufficient for gamma-ray spectroscopy and pulse shape analysis using coaxial high purity germanium detectors.
F. E. A. de Souza, M. O. Tahim, R.I. de Oliveira Junior
et al.
Abstract In this work we discuss the issue of localization of $$N=2$$ N = 2 spinning particles. More specifically, we show that we can not confine the spinning particle within the Randall–Sundrum scenario. We argue that this result directly affects studies related to localization of p-form fields. We show that, due to the non confinement of the superparticle, we can not localize p-forms on the membrane.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Kabelo Tsiane, Sidney Mau, Alex Drlica-Wagner
et al.
We predict the sensitivity of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) to faint, resolved Milky Way satellite galaxies and outer-halo star clusters. We characterize the expected sensitivity using simulated LSST data from the LSST Dark Energy Science Collaboration (DESC) Data Challenge 2 (DC2) accessed and analyzed with the Rubin Science Platform as part of the Rubin Early Science Program. We simulate resolved stellar populations of Milky Way satellite galaxies and outer-halo star clusters over a wide range of sizes, luminosities, and heliocentric distances, which are broadly consistent with expectations for the Milky Way satellite system. We inject simulated stars into the DC2 catalog with realistic photometric uncertainties and star/galaxy separation derived from the DC2 data itself. We assess the probability that each simulated system would be detected by LSST using a conventional isochrone matched-filter technique. We find that assuming perfect star/galaxy separation enables the detection of resolved stellar systems with $M_V$ = 0 mag and $r_{1/2}$ = 10 pc with >50% efficiency out to a heliocentric distance of ~250 kpc. Similar detection efficiency is possible with a simple star/galaxy separation criterion based on measured quantities, although the false positive rate is higher due to leakage of background galaxies into the stellar sample. When assuming perfect star/galaxy classification and a model for the galaxy-halo connection fit to current data, we predict that 89 +/- 20 Milky Way satellite galaxies will be detectable with a simple matched-filter algorithm applied to the LSST wide-fast-deep data set. Different assumptions about the performance of star/galaxy classification efficiency can decrease this estimate by ~7-25%, which emphasizes the importance of high-quality star/galaxy separation for studies of the Milky Way satellite population with LSST.
Ilkham Galiullin, Antonio C. Rodriguez, Kareem El-Badry
et al.
Accreting white dwarfs (WDs) in close binary systems, commonly known as cataclysmic variables (CVs), with orbital periods below the canonical period minimum (≈80 minutes) are rare. Such short periods can only be reached if the donor star in the CV is either significantly evolved before initiating mass transfer to the WD or is metal-poor. We present optical photometry and spectroscopy of Gaia19bxc, a high-amplitude variable identified as a polar CV with an exceptionally short orbital period of 64.42 minutes—well below the canonical CV period minimum. High-speed photometry confirms persistent double-peaked variability consistent with cyclotron beaming, thus indicating the presence of a magnetic WD. Phase-resolved Keck/Low-Resolution Imaging Spectrometer (LRIS) spectroscopy reveals strong hydrogen and helium emission lines but no donor features, indicating the accretor is a magnetic WD and the donor is hydrogen-rich, but cold and faint. The absence of a detectable donor and the low inferred temperature (≲3500 K) disfavor an evolved donor scenario. Instead, the short period and the system’s halo-like kinematics suggest Gaia19bxc may be the first known metal-poor polar. Because metal-poor donors are more compact than solar-metallicity donors of the same mass, they can reach shorter minimum periods. Gaia19bxc is one of only a handful of known metal-poor CVs below the canonical period minimum and has the shortest period of any such magnetic system discovered to date.
We use a sample of 54 compact symmetric objects (CSOs) to confirm that there are two unrelated CSO classes: an edge-dimmed, low-luminosity class (CSO 1), and an edge-brightened, high-luminosity class (CSO 2). Using blind tests, we show that CSO 2s consist of three subclasses: CSO 2.0, having prominent hot spots at the leading edges of narrow jets and/or narrow lobes; CSO 2.2, without prominent hot spots and with broad jets and/or lobes; and CSO 2.1, which exhibit mixed properties. Most CSO 2s do not evolve into larger jetted active galactic nuclei (AGN), but spend their whole life cycle as CSOs of size ≲500 pc and age ≲5000 yr. The minimum energies needed to produce the radio luminosity and structure in CSO 2s range from ∼10 ^−4 M _⊙ c ^2 to ∼7 M _⊙ c ^2 . We show that the transient nature of most CSO 2s, and their birth rate, can be explained through ignition in the tidal disruption events of stars. We also consider possibilities of tapping the spin energy of the supermassive black hole, and tapping the energy of the accretion disk. Our results demonstrate that CSOs constitute a large family of AGN in which we have thus far studied only the brightest. More comprehensive CSO studies, with higher sensitivity, resolution, and dynamic range, will revolutionize our understanding of AGN and the central engines that power them.
Several ongoing and upcoming large-scale structure surveys aim to explore the nonlinear regime of structure formation with high precision. Making reliable cosmological inferences from these observations necessitates precise theoretical modeling of the mildly nonlinear regime. In this work we explore how the choice of nonlinear prescription would impact parameter estimation from cosmic shear measurements for a Euclid-like survey. Specifically, we employ two different nonlinear prescriptions of halofit and the Effective Field Theory of the Large Scale Structure and compare their measurements for the three different cosmological scenarios of ΛCDM, w CDM, and ( w _0 , w _a ) CDM. We also investigate the impact of different nonlinear cutoff schemes on parameter estimation. We find that the predicted errors on most parameters shrink considerably as smaller scales are included in the analysis, with the amount depending on the nonlinear prescription and the cutoff scheme used. We use predictions from the halofit model to analyze the mock data from DarkSky N -body simulations and quantify the parameter bias introduced in the measurements due to the choice of nonlinear prescription. We observe that σ _8 and n _s have the largest measurement bias induced by inaccuracies of the halofit model.
Emily K. Deibert, Ernst J. W. de Mooij, Ray Jayawardhana
et al.
We present high-resolution transmission spectroscopy of WASP-76b with Gemini Remote Access to CFHT ESPaDOnS Spectrograph (GRACES)/Gemini North obtained as part of the ExoGemS survey. With a broad spectral range of 400–1050 nm and a relatively high resolution of ∼66,000, these observations are particularly well suited to searching for atomic and molecular atmospheric species via the Doppler cross-correlation technique. We recover absorption features due to neutral iron (Fe i ), sodium (Na i ), and ionized calcium (Ca ii ) at high significance (>5 σ ), and investigate possible atmospheric temperatures and wind speeds. We also report tentative (>3 σ ) detections of Li i , K i , Cr i , and V i in the atmosphere of WASP-76b. Finally, we report nondetections of a number of other species, some of which have previously been detected with other instruments. Through model injection/recovery tests, we demonstrate that many of these species are not expected to be detected in our observations. These results allow us to place GRACES and the ExoGemS survey in context with other high-resolution optical spectrographs.
Both entropy and complexity are central concepts for the understanding and development of Information Theory, playing an essential role in the increasingly numerous applications in a huge diversity of fields [...]
Abstract In this article, cracking technique is developed for spherically symmetric compact sources in the framework of f(R, T) gravity, where R denotes Ricci scalar and T stands for trace of energy momentum tensor. The characteristics of a star with anisotropic pressure stresses are investigated by utilizing the Tolman–Kuchowicz spacetime solutions. Modified field equations are developed for a particular model i.e., $$f(R,T)=R+2\gamma T$$ f ( R , T ) = R + 2 γ T , where $$\gamma $$ γ is constant, that are further used to develop expressions for matter density, radial and tangential pressures. A generalized form of the Tolman Oppenheimer Volkoff (TOV) equation is developed for the modified field equations. The consequence of the local density perturbation scheme, as presented by Biswas et al. (Eur Phys J C 80:175, 2020) is considered. The mathematical framework for cracking has been tested on five realistic stars namely, Vela X-1, Cen X-3, SMC X-1, PSR J1614-2230 and PSR J1903+327. The graph of forces distribution of these stars have been observed to check the stability regions. The results of cracking/overturning for various values of the parameters involved in this model are observed by checking the instability regions in the form intervals.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Jiale Gu, Shafqat Riaz, Askar B. Abdikamalov
et al.
Abstract Bumblebee gravity is one of the simplest gravity theories with spontaneous Lorentz symmetry breaking. Since we know a rotating black hole solution in bumblebee gravity, we can potentially test this model with the available astrophysical observations of black holes. In this work, we construct a reflection model in bumblebee gravity and we use our model to analyze the reflection features of a NuSTAR spectrum of the Galactic black hole EXO 1846-031 in order to constrain the Lorentz-violating parameter $$\ell $$ ℓ . We find that the analysis of the reflection features in the spectrum of EXO 1846-031 cannot constrain the parameter $$\ell $$ ℓ because of a very strong degeneracy between the estimates of $$\ell $$ ℓ and of the black hole spin parameter $$a_*$$ a ∗ . Such a degeneracy may be broken by combining other observations.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Elias Riedel Gårding, Nicolas Schwaller, Chun Lam Chan
et al.
We propose the first correct special-purpose quantum circuits for preparation of Bell diagonal states (BDS), and implement them on the IBM Quantum computer, characterizing and testing complex aspects of their quantum correlations in the full parameter space. Among the circuits proposed, one involves only two quantum bits but requires adapted quantum tomography routines handling classical bits in parallel. The entire class of Bell diagonal states is generated, and several characteristic indicators, namely entanglement of formation and concurrence, CHSH non-locality, steering and discord, are experimentally evaluated over the full parameter space and compared with theory. As a by-product of this work, we also find a remarkable general inequality between “quantum discord” and “asymmetric relative entropy of discord”: the former never exceeds the latter. We also prove that for all BDS the two coincide.
Osvaldo L. Santos-Pereira, Everton M. C. Abreu, Marcelo B. Ribeiro
Abstract The Alcubierre warp drive metric is a spacetime geometry featuring a spacetime distortion, called a warp bubble, where a massive particle inside it acquires global superluminal velocities, or warp speeds. This work presents solutions of the Einstein equations for the Alcubierre metric having fluid matter as gravity source. The energy–momentum tensor considered has two fluid contents, the perfect fluid and the parametrized perfect fluid (PPF), a tentative more flexible model whose aim is to explore the possibilities of warp drive solutions with positive matter density content. Santos-Pereira et al. (Eur Phys J C 80:786, 2020) already showed that the Alcubierre metric having dust as source connects this geometry to the Burgers equation, which describes shock waves moving through an inviscid fluid, but led the solutions back to vacuum. The same happened for two out of four solutions subcases for the perfect fluid. Other solutions for the perfect fluid indicate the possibility of warp drive with positive matter density, but at the cost of a complex solution for the warp drive regulating function. Regarding the PPF, solutions were also obtained indicating that warp speeds could be created with positive matter density. Weak, dominant, strong and null energy conditions were calculated for all studied subcases, being satisfied for the perfect fluid and creating constraints in the PPF quantities such that a positive matter density is also possible for creating a warp bubble. Summing up all results, energy–momentum tensors describing more complex forms of matter or field distributions generate solutions for the Einstein equations with the warp drive metric where a negative matter density might not be a strict precondition for attaining warp speeds.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
Fernando E. Serna, Roberto Correa da Silveira, J. J. Cobos-Martínez
et al.
Abstract The ladder kernel of the Bethe–Salpeter equation is amended by introducing a different flavor dependence of the dressing functions in the heavy-quark sector. Compared with earlier work this allows for the simultaneous calculation of the mass spectrum and leptonic decay constants of light pseudoscalar mesons, the $$D_u$$ D u , $$D_s$$ D s , $$B_u$$ B u , $$B_s$$ B s and $$B_c$$ B c mesons and the heavy quarkonia $$\eta _c$$ η c and $$\eta _b$$ η b within the same framework at a physical pion mass. The corresponding Bethe–Salpeter amplitudes are projected onto the light front and we reconstruct the distribution amplitudes of the mesons in the full theory. A comparison with the first inverse moment of the heavy meson distribution amplitude in heavy quark effective theory is made.
Astrophysics, Nuclear and particle physics. Atomic energy. Radioactivity
The CMS collaboration, A. M. Sirunyan, A. Tumasyan
et al.
Abstract A search for dark matter (DM) particles is performed using events with a Higgs boson candidate and large missing transverse momentum. The analysis is based on proton- proton collision data at a center-of-mass energy of 13 TeV collected by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 fb −1. The search is performed in five Higgs boson decay channels: h → b b ¯ $$ \mathrm{h}\to \mathrm{b}\overline{\mathrm{b}} $$ , γγ, τ + τ − , W+W − , and ZZ. The results from the individual channels are combined to maximize the sensitivity of the analysis. No significant excess over the expected standard model background is observed in any of the five channels or in their combination. Limits are set on DM production in the context of two simplified models. The results are also interpreted in terms of a spin-independent DM-nucleon scattering cross section and compared to those from direct-detection DM experiments. This is the first search for DM particles produced in association with a Higgs boson decaying to a pair of W or Z bosons, and the first statistical combination based on five Higgs boson decay channels.
Nuclear and particle physics. Atomic energy. Radioactivity