Mass Scale Research Articles

Zingiber Officinale-assisted Graphene Oxide Green Reduction for Excellent Photocatalysis

Introduction: A facile approach for producing graphene nanosheets (GNs) has been established by reducing graphene oxide (GO) with ginger extract (GEx) at low temperature. The elimination of oxygen characteristics from GO has been validated by a Raman study. Method: FTIR analysis also supports the Raman signatures of the removal of oxygen species from the carbon core. Surface analysis confirms the remarkable deoxidation of GO and settles the production of GNs. After that, synthesized GNs were tested for their capability to photodegrade Methylene blue (MB) dye under visible and UV (both 125 W) light. Result: At low concentrations (0.5 mg), GNs are an effective photocatalyst for the degradation of MB, with a maximum degradation efficiency of 91.84% in 45 minutes when exposed to UV light irradiation. Conclusion: Results favor that the GEx provides a potential substitute for toxic or harmful reducing agents for the ecologically sustainable production of GNs on a mass scale and synthesized GNs act as an excellent photocatalyst against MB.

Copacabana: A probabilistic membership assignment method for galaxy clusters

Abstract Cosmological analyses using galaxy clusters in optical/NIR photometric surveys require robust characterization of their galaxy content. Precisely determining which galaxies belong to a cluster is crucial. In this paper, we present the COlor Probabilistic Assignment of Clusters And BAyesiaN Analysis (Copacabana) algorithm. Copacabana computes membership probabilities for all galaxies within an aperture centred on the cluster using photometric redshifts, colours, and projected radial probability density functions. We use simulations to validate Copacabana and we show that it achieves up to 89% membership accuracy with a mild dependency on photometric redshift uncertainties and choice of aperture size. We find that the precision of the photometric redshifts has the largest impact on the determination of the membership probabilities followed by the choice of the cluster aperture size. We also quantify how much these uncertainties in the membership probabilities affect the stellar mass–cluster mass scaling relation, a relation that directly impacts cosmology. Using the sum of the stellar masses weighted by membership probabilities ($\rm \mu _{\star }$) as the observable, we find that Copacabana can reach an accuracy of 0.06 dex in the measurement of the scaling relation at low redshift for a LSST type survey. These results indicate the potential of Copacabana and $\rm \mu _{\star }$ to be used in cosmological analyses of optically selected clusters in the future.

HOLISMOKES. XIII. Strong-lens candidates at all mass scales and their environments from the Hyper-Suprime Cam and deep learning

HOLISMOKES. XIII. Strong-lens candidates at all mass scales and their environments from the Hyper-Suprime Cam and deep learning

Observational prospects of self-interacting scalar superradiance with next-generation gravitational-wave detectors

Abstract Current- and next-generation gravitational-wave observatories may reveal new, ultralight bosons. Through the superradiance process, these theoretical particle candidates can form clouds around astrophysical black holes and result in detectable gravitational-wave radiation. In the absence of detections, constraints—contingent on astrophysical assumptions—have been derived using LIGO-Virgo-KAGRA data on boson masses. However, the searches for ultralight scalars to date have not adequately considered self-interactions between particles. Self-interactions that significantly alter superradiance dynamics are generically present for many scalar models, including axion-like dark matter candidates and string axions. We implement the most complete treatment of particle self-interactions available to determine the gravitational-wave signatures expected from superradiant scalar clouds and revisit the constraints obtained in a past gravitational-wave search targeting the black hole in Cygnus X-1. We also project the reach of next-generation gravitational-wave observatories to scalar particle parameter space in the mass-coupling plane. We find that while proposed observatories have insufficient reach to self-interactions that can halt black hole spin down, next-generation observatories are essential for expanding the search beyond gravitational parameter space and can reach a mass and interaction scale of ∽ 10-13–10-12 eV/c2 and ≥ 1017 GeV, respectively.

Exploring the Thermodynamic Uncertainty Constant: Insights from a Quasi-Ideal Nano-Gas Model

In previous work, we investigated thermodynamic processes in systems at the mesoscopic level where traditional thermodynamic descriptions (macroscopic or microscopic) may not be fully adequate. The key result is that entropy in such systems does not change continuously, as in macroscopic systems, but rather in discrete steps characterized by the quantization constant β. This quantization reflects the underlying discrete nature of the collision process in low-dimensional systems and the essential role played by thermodynamic fluctuations at this scale. Thermodynamic variables conjugate to the forces, along with Glansdorff–Prigogine’s dissipative variable can be discretized, enabling a mesoscopic-scale formulation of canonical commutation rules (CCRs). In this framework, measurements correspond to determining the eigenvalues of operators associated with key thermodynamic quantities. This work investigates the quantization parameter β in the CCRs using a nano-gas model analyzed through classical statistical physics. Our findings suggest that β is not an unknown fundamental constant. Instead, it emerges as the minimum achievable value derived from optimizing the uncertainty relation within the framework of our model. The expression for β is determined in terms of the ratio χ, which provides a dimensionless number that reflects the relative scales of volume and mass between entities at the Bohr (atomic level) and the molecular scales. This latter parameter quantifies the relative influence of quantum effects versus classical dynamics in a given scattering process.

WALLABY Pilot Survey: Gas-rich Galaxy Scaling Relations from Marginally Resolved Kinematic Models

We present the first set of galaxy scaling relations derived from kinematic models of the Widefield Australian Square Kilometer Array Pathfinder (ASKAP) L-band Legacy All-sky Blind surveY (WALLABY) pilot phase observations. Combining the results of the first and second pilot data releases, there are 236 available kinematic models. We develop a framework for robustly measuring H i disk structural properties from these kinematic models, applicable to the full WALLABY survey. Utilizing this framework, we obtained the H i size, a measure of the rotational velocity, and angular momentum for 148 galaxies. These comprise the largest sample of galaxy properties from an untargeted, uniformly observed, and modeled H i survey to date. We study the neutral atomic hydrogen (H i) size–mass, size–velocity, mass–velocity, and angular momentum–mass scaling relations. We calculate the slope, intercept, and scatter for these scaling relations and find that they are similar to those obtained from other H i surveys. We also obtain stellar masses for 92 of the 148 robustly measured galaxies using multiband photometry through Dark Energy Sky Instrument Legacy Imaging Survey Data Release 10 images. We use a subset of 61 of these galaxies that have consistent optical and kinematic inclinations to examine the stellar and baryonic Tully–Fisher relations as well as the gas fraction–disk stability and gas fraction–baryonic mass relations. These measurements and relations demonstrate the unprecedented resource that WALLABY will represent for resolved galaxy scaling relations in H i.

Gravitationally misaligned ultralight dark matter and implications for neutron stars

We examine the possibility that dark matter (DM) may be an ultralight scalar that was misaligned via nonminimal coupling to gravity, in the early Universe. For a certain regime of scalar masses, gravitational effects in neutron stars could place interesting bounds on the viable parameter space of the model, even in the absence of nongravitational interactions between DM and ordinary matter. Published by the American Physical Society 2024

U(1)-charged Dark Matter in three-Higgs-doublet models

We explore three-Higgs-doublet models that may accommodate scalar Dark Matter where the stability is based on an unbroken U(1)-based symmetry, rather than the familiar ℤ2 symmetry. Our aim is to classify all possible ways of embedding a U(1) symmetry in a three-Higgs-doublet model. The different possibilities are presented and compared. All these models contain mass-degenerate pairs of Dark Matter candidates due to a U(1) symmetry unbroken (conserved) by the vacuum. Most of these models preserve CP. In the CP-conserving case the pairs can be seen as one being even and the other being odd under CP or as having opposite charges under U(1). Not all symmetries presented here were identified before in the literature, which points to the fact that there are still many open questions in three-Higgs-doublet models. We also perform a numerical exploration of the U(1) × U(1)-symmetric 3HDM, this is the most general phase-invariant (real) three-Higgs-doublet model. The model contains a multi-component Dark Matter sector, with two independent mass scales. After imposing relevant experimental constraints we find that there are possible solutions throughout a broad Dark Matter mass range, 45–2000 GeV, the latter being a scan cutoff.

Establishing the Institute of Independent Evaluation of Higher Education in the Russian Federation

The paper presents the results of the search, systematization and analysis of independent higher education evaluation systems that have been developed in the country in the recent decade. The research has been carried out using standardised evaluation mechanisms that adhere to the criteria of mass scale, openness, and stability. The analysis of the independent evaluation of higher education’s present situation revealed certain inconsistencies between the legislative and regulatory framework and real practice. It should be emphasised that, while different processes have now been developed for this type of evaluation, they still require enhancement. The assessment mechanisms themselves need to undergo an external, independent evaluation to ensure their reliability, integrity, and trustworthy evidence. It has been indicated that independent evaluation procedures have jointly developed into a system: the institution of independent evaluation. This system is characterised by integrity, orderliness, and definite linkages. One may consider the aggregating technology of the aforementioned evalu-ations to be the synergistic outcome of the system’s establishment. In order to achieve a synergistic effect on the evaluation of all higher education institutions and educational programmes in the country, the authors suggest a method for aggregating the outcomes of the described evaluation procedures. The obtained research outcomes prove their applicability to the internal and external evaluation of a higher education institution’s performance and to the strategic planning of the development of both the institution and the higher education system.

The atomic gas sequence and mass–metallicity relation from dwarfs to massive galaxies

ABSTRACT Galaxy scaling relations provide insights into the processes that drive galaxy evolution. The extension of these scaling relations into the dwarf galaxy regime is of particular interest. This is because dwarf galaxies represent a crucial stage in galaxy evolution, and understanding them could also shed light on their role in reionizing the early Universe. There is currently no consensus on the processes that dominate the evolution of dwarfs. In this work, we constrain the atomic gas sequence (stellar mass versus atomic gas fraction) and mass–metallicity relation (stellar mass versus gas-phase metallicity) from dwarf ($10^{6.5} \, {\rm M}_{\odot }$) to massive ($10^{11.5} \, {\rm M}_{\odot }$) galaxies in the local Universe. The combined optical and 21-cm spectroscopic observations of the Dark Energy Spectroscopic Instrument and Arecibo Legacy Fast ALFA surveys allow us to constrain both scaling relations simultaneously. We find a slope change of the atomic gas sequence at a stellar mass of ${\sim} 10^{9} \, \textrm{M}_{\odot }$. We also find that the shape and scatter of the atomic gas sequence and mass–metallicity relation are strongly linked for both dwarfs and more massive galaxies. Consequently, the low-mass slope change of the atomic gas sequence is imprinted onto the mass–metallicity relation of dwarf galaxies. The mass scale of the measured slope change is consistent with a predicted escape velocity threshold below which low-mass galaxies experience significant supernova-driven gas loss, as well as with a reduction in cold gas accretion onto more massive galaxies.

Tetraquarks made of sufficiently unequal-mass heavy quarks are bound in QCD

Tetraquarks, bound states composed of two quarks and two antiquarks, have been the subject of intense study but are challenging to understand from first principles. We apply variational and Green’s function Monte Carlo methods to compute tetraquark ground-state energies in potential nonrelativistic QCD using a wide range of color and spatial wave functions. We find no evidence for bound tetraquarks composed of equal-mass quarks and antiquarks. Conversely, we find clear evidence for the existence of bound tetraquarks for sufficiently unequal quark/antiquark mass ratios at all overall mass scales where our effective theory results are applicable. We predict the critical mass ratios for bound state formation and study tetraquark bound states’ spatial and color structure at leading order and next-to-leading order in potential nonrelativistic QCD. Published by the American Physical Society 2024

The baryon census and the mass-density of stars, neutral gas, and hot gas as a function of halo mass

Abstract We study the stellar, neutral gas content within halos over a halo mass range 1010to1015.5M⊙ and hot X-ray gas content over a halo mass range 1012.8to1015.5M⊙ in the local universe. We combine various empirical datasets of stellar, H i and X-ray observations of galaxies, groups and clusters to establish fundamental baryonic mass vs halo mass scaling relations. These scaling relations are combined with halo mass function to obtain the baryon densities of stars, neutral gas and hot gas (T > 106K), as a function of halo mass. We calculate the contributions of the individual baryonic components to the cosmic baryon fraction. Cosmic stellar mass density ($\Omega _\text{star}=2.09^{+0.21}_{-0.18} \times 10^{-3}$), cosmic H i mass density ($\Omega _\rm{H\,{\small I}}=0.49^{+0.25}_{-0.12} \times 10^{-3}$) and cosmic neutral gas mass density ($\Omega _\text{neutral gas}=0.71^{+0.39}_{-0.18} \times 10^{-3}$) estimates are consistent with previous more direct method measurements of these values, thereby establishing the veracity of our method. We also give an estimate of the cosmic hot plasma density ($\Omega _\text{hot gas}=2.58^{+2.1}_{-0.66} \times 10^{-3}$).

Genomic surveillance of Canadian airport wastewater samples allows early detection of emerging SARS-CoV-2 lineages

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has shown wastewater (WW) surveillance to be an effective means of tracking the emergence of viral lineages which arrive by many routes of transmission including via transportation hubs. In the Canadian province of Ontario, numerous municipal wastewater treatment plants (WWTPs) participate in WW surveillance of infectious disease targets such as SARS-CoV-2 by qPCR and whole genome sequencing (WGS). The Greater Toronto Airports Authority (GTAA), operator of Toronto Pearson International Airport (Toronto Pearson), has been participating in WW surveillance since January 2022. As a major international airport in Canada and the largest national hub, this airport is an ideal location for tracking globally emerging SARS-CoV-2 variants of concern (VOCs). In this study, WW collected from Toronto Pearson’s two terminals and pooled aircraft sewage was processed for WGS using a tiled-amplicon approach targeting the SARS-CoV-2 virus genome. Data generated was analyzed to monitor trends of SARS-CoV-2 lineage frequencies. Initial detections of emerging lineages were compared between Toronto Pearson WW samples, municipal WW samples collected from the surrounding regions, and Ontario clinical data as published by Public Health Ontario. Results enabled the early detection of VOCs and individual mutations emerging in Ontario. On average, the emergence of novel lineages at the airport preceded clinical detections by 1–4 weeks, and up to 16 weeks in one case. This project illustrates the efficacy of WW surveillance at transitory transportation hubs and sets an example that could be applied to other viruses as part of a pandemic preparedness strategy and to provide monitoring on a mass scale.

Environmental Quenching of Low-surface-brightness Galaxies Near Hosts from Large Magellanic Cloud to Milky Way Mass Scales

Low-surface-brightness galaxies (LSBGs) are excellent probes of quenching and other environmental processes near massive galaxies. We study an extensive sample of LSBGs near massive hosts in the local universe that are distributed across a diverse range of environments. The LSBGs with surface-brightness μeff,g>24.2magarcsec−2 are drawn from the Dark Energy Survey Year 3 catalog while the hosts with masses 9.0<log(M⋆/M⊙)<11.0 comparable to the Milky Way and the Large Magellanic Cloud are selected from the z0MGS sample. We study the projected radial density profiles of LSBGs as a function of their color and surface brightness around hosts in both the rich Fornax–Eridanus cluster environment and the low-density field. We detect an overdensity with respect to the background density, out to 2.5 times the virial radius for both hosts in the cluster environment and the isolated field galaxies. When the LSBG sample is split by g − i color or surface brightness μ eff, g , we find the LSBGs closer to their hosts are significantly redder and brighter, like their high-surface-brightness counterparts. The LSBGs form a clear “red sequence” in both the cluster and isolated environments that is visible beyond the virial radius of the hosts. This suggests preprocessing of infalling LSBGs and a quenched backsplash population around both host samples. More so, the relative prominence of the “blue cloud” feature implies that preprocessing is ongoing near the isolated hosts compared to the cluster environment where the LSBGs are already well processed.

Tomography of flavoured leptogenesis with primordial blue gravitational waves

We explore a scenario where an early epoch of matter domination is driven by the mass scale MN of the right-handed neutrinos, which also characterizes the different flavour regimes of leptogenesis. Such a matter-domination epoch gives rise to peculiar spectral imprints on primordial Gravitational Waves (GWs) produced during inflation. We point out that the characteristic spectral features are detectable in multiple frequency bands with current and future GW experiments in case of Blue GWs (BGWs) described by a power-law with a positive spectral index (nT > 0) and an amplitude compatible with Cosmic Microwave Background (CMB) measurements at the CMB scale. We find that the three-flavour leptogenesis regime with MN ≲ 109 GeV imprints BGWs more prominently than the two-flavour and one-flavour regimes characterized by a higher right-handed neutrino mass. In particular, a two-flavour (three-flavour) leptogenesis regime is expected to leave distinct imprints in the mHz–Hz (μHz–mHz) band. Moreover, we translate the current Big Bang Nucleosynthesis (BBN) and LIGO limits on the GW energy density into constraints on the flavour leptogenesis parameter space for different GW spectral indices nT . We provide a rigorous statistical analysis of how the future GW detectors would be conjointly able to distinguish the flavour regimes. Interestingly, the scenario also offers unique GW signals testable in the next LIGO run with a correlated signature in the PTA frequency band with an amplitude comparable to the one expected from supermassive black holes.

Dust Drift Timescales in Protoplanetary Disks at the Cusp of Gravitational Instability

Millimeter emitting dust grains have sizes that make them susceptible to drift in protoplanetary disks due to the difference between their orbital speed and that of the gas. The characteristic drift timescale depends on the surface density of the gas. By comparing disk radius measurements from Atacama Large Millimeter/submillimeter Array CO and continuum observations at millimeter wavelengths, the gas surface density profile and dust drift time can be self-consistently determined. We find that profiles which match the measured dust mass have very short drift timescales, an order of magnitude or more shorter than the stellar age, whereas profiles for disks that are on the cusp of gravitational instability, defined via the minimum value of the Toomre parameter, Qmin∼1−2 , have drift timescales comparable to the stellar lifetime. This holds for disks with masses of dust ≳5 M ⊕ across a range of absolute ages from less than 1 Myr to over 10 Myr. The inferred disk masses scale with stellar mass as Mdisk≈M*/5Qmin . This interpretation of the gas and dust disk sizes simultaneously solves two long standing issues regarding the dust lifetime and exoplanet mass budget, and suggests that we consider millimeter wavelength observations as a window into an underlying population of particles with a wide size distribution in secular evolution with a massive planetesimal disk.

Reverberation Mapping of High-mass and High-redshift Quasars Using Gravitational Time Delays

Mass estimates of black holes (BHs) in the centers of active galactic nuclei (AGNs) often rely on the radius–luminosity relation. However, this relation, usually probed by reverberation mapping (RM), is poorly constrained in the high-luminosity and high-redshift ends due to the very long expected RM lag times. Multiply imaged AGNs may offer a unique opportunity to explore the radius–luminosity relation at these ends. In addition to comprising several magnified images enabling a more efficient light-curve sampling, the time delay between multiple images of strongly lensed quasars can also aid in making such RM measurements feasible on reasonable timescales: if the strong-lensing time delay is, for example, of the order of the expected RM time lag, changes in the emission lines in the leading image can be observed around the same time as the changes in the continuum in the trailing image. In this work we probe the typical time-delay distribution in galaxy-cluster lenses and estimate the number of both high-mass (∼109−1010 M ⊙) and high-redshift (z ≳ 4−12) quasars that are expected to be strongly lensed by clusters. We find that up to several tens of thousands of M BH ∼ 106–108 M ⊙ broad-line AGNs at z > 4 should be multiply imaged by galaxy clusters and detectable with JWST, hundreds with Euclid, and several thousand with the Roman Space Telescope, across the whole sky. These could supply an important calibration for the BH mass scaling in the early Universe.

Limits on scalar dark matter interactions with particles other than the photon via loop corrections to the scalar-photon coupling

There is limited information about the interaction strength of a scalar dark matter candidate with hadrons and leptons for a scalar particle mass exceeding 10−3 eV while its interaction with photon is well studied. The scalar-photon coupling constant receives quantum corrections from one-loop Feynman diagrams which involve the scalar-lepton, scalar-quark, and scalar-W-boson vertices. We calculate these one-loop quantum corrections and find new limits on the scalar particle interactions with electron, muon, tau, quarks, nucleons, gluons, Higgs, and W-bosons by repurposing the results of experiments measuring the scalar-photon interaction. Limits on interactions of heavy leptons and quarks have been obtained for the first time, and limits on other interactions in certain mass intervals are 2 to 15 orders of magnitude stronger than those presented in previous publications and exclude the resolution of the muon g−2 anomaly with scalar particle. Published by the American Physical Society 2024

Primordial Black Holes Generated by Fast-roll Mechanism in Noncanonical Natural Inflation

In this work, a new fast-roll (FR) mechanism to generate primordial black holes (PBHs) and gravitational waves (GWs) in generalized noncanonical natural inflation is introduced. In this model, choosing a suitable function for noncanonical mass scale parameter M(ϕ) gives rise to produce a cliff-like region in the field evolution path. When inflaton rolls down the steep cliff, its kinetic energy during an FR stage increases in comparison with a slow-roll stage. Hence, seeds of PBH production are born in this transient FR stage. Depending on the position of the cliff, appropriate cases of PBHs for explaining total dark matter, microlensing effects, LIGO–Virgo events, and NANOGrav 15 yr data can be formed. The density spectrum of GWs related to one case of the model lies in the NANOGrav 15 yr domain and behaves like ΩGW0∼f5−γ . The spectral index γ = 3.42 for this case satisfies the NANOGrav 15 yr constraint. Moreover, regarding reheating considerations, it is demonstrated that PBHs are born in the radiation-dominated era. Furthermore, viability of the model in light of theoretical swampland criteria and observational constraints on cosmic microwave background scales are illustrated.

Massive scalar clouds and black hole spacetimes in Gauss-Bonnet gravity

We study static black holes in scalar-Gauss-Bonnet (sGB) gravity with a massive scalar field as an example of higher curvature gravity. The scalar mass introduces an additional scale and leads to a strong suppression of the scalar field beyond its Compton wavelength. We numerically compute sGB black hole spacetimes and scalar configurations and also compare with perturbative results for small couplings, where we focus on a dilatonic coupling function. We analyze the constraints on the parameters from requiring the curvature singularity to be located inside the black hole horizon r_hrh and the relation to the regularity condition for the scalar field. For scalar field masses m r_h \gtrsim 10^{-1}mrh≳10−1, this leads to a new and currently most stringent bound on sGB coupling constant \alphaα of \alpha/r_h^2\sim 10^{-1}α/rh2∼10−1 in the context of stellar mass black holes. Lastly, we look at several properties of the black hole configurations relevant for further work on observational consequences, including the scalar monopole charge, Arnowitt–Deser–Misner mass, curvature invariants and the frequencies of the innermost stable circular orbit and light ring.