Galaxy Formation and Evolution

Aims. We study galaxy clustering and explore the dependence of galaxy properties on the the environment up to a redshift z ∼ 1, on the basis of a deep multi-band survey in the Chandra Deep Field South. Methods. We have developed a new method which combines galaxy angular positions and photometric redshifts to estimate the local galaxy number-density. This allows both the detection of overdensities in the galaxy distribution and the study of the properties of the galaxy population as a function of the environmental density. Results. We detect two moderate overdensities at z ∼ 0.7 and z ∼ 1 previously identified spectroscopically. We find that the fraction of red galaxies within each structure increases with volume density, extending to z ∼ 1 previous results. We measure "red sequence" slopes consistent with the values found in X-ray selected clusters, supporting the notion that the mass-metallicity relation hold constant up to z ∼ 1. Conclusions. Our method based on photometric redshifts allows to extend structure detection and density estimates up to the limits of photometric surveys, i.e. considerably deeper than spectroscopic surveys. Since X-ray cluster detection at high redshift is presently limited to massive relaxed structures, galaxy volume density based on photometric redshift appears as a valuable tool in the study of galaxy evolution.

In this study groundwater contaminants in Owerri zone in Imo state made up of nine local government areas were investigated. Four (4) groundwater samples were collected from each local government area. This amounted to thirty-six groundwater samples. These samples were collected randomly from sites close to septic tanks and to avoid contamination from tanks, the samples were collected at the well head, before water enters into storage tanks. Three (3) liters of water were collected from sample after pumping for about 3-5 minutes to ensure collection of representative samples. Samples were analyzed for microbiological parameters like BOD, TVC and coliform. A three-in-one pH meter was used to determine the pH and total dissolved solids (TDS) of the water samples while conductivity meter was employed for the determination of electrical conductivity. Spectrophotometer was used in the determination of different chemical parameters (sodium, potassium, chloride, nitrate and sulphate). Other analysis for magnesium and calcium were done by Complexometric titration method. These results were used to ascertain the levels of groundwater contamination in Owerri zone. An equation was generated from the chemical parameters using SPSS and E-view softwares to estimate the minimum allowable distance for locating borehole from sources of contamination in Owerri zone in Imo state Nigeria. The minimum allowable distance calculated for groundwater from sources of contamination is 14.48 meters.

The investigation of distant galaxy formation and evolution is a powerful tool to constrain dark matter scenarios, supporting and in some cases surpassing other astrophysical and experimental probes. The recent completion of the Hubble Frontier Field (HFF) programme combining ultra-deep Hubble Space Telescope observations and the magnification power of gravitational lensing produced by foreground galaxy clusters has enabled the detection of the faintest primordial galaxies ever studied. Here we show how the number density of such primordial galaxies allows to constrain a variety of DM models alternative to CDM. In particular, it provides stringent limits on the mass of thermal WDM candidates, on the parameter space of sterile neutrino production models, and on other DM scenarios featuring particles in the keV mass range which is also supported by recent detections of a 3.5keV X-ray line. These constraints are robust and independent of the baryonic physics modeling of galaxy formation and evolution. Fuzzy DM (ultralight DM particles) results strongly disfavored.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Context. We introduce the Dwarf Galaxy Survey with Amateur Telescopes (DGSAT) project and report the discovery of eleven low surface brightness (LSB) galaxies in the fields of the nearby galaxies NGC 2683, NGC 3628, NGC 4594 (M 104), NGC 4631, NGC 5457 (M 101), and NGC 7814. Aims. The DGSAT project aims to use the potential of small-sized telescopes to probe LSB features around large galaxies and to increase the sample size of the dwarf satellite galaxies in the Local Volume. Methods. Using long exposure images, fields of the target spiral galaxies are explored for extended LSB objects. After identifying dwarf galaxy candidates, their observed properties are extracted by fitting models to their light profiles. Results. We find three, one, three, one, one, and two new LSB galaxies in the fields of NGC 2683, 3628, 4594, 4631, 5457, and 7814, respectively. In addition to the newly found galaxies, we analyse the structural properties of nine already known galaxies. All of these 20 dwarf galaxy candidates have effective surface brightnesses in the range 25.3 < ∼ µ e < ∼ 28.8 mag arcsec -2 and are fit with Sersic profiles with indices n < ∼ 1. Assuming that they are in the vicinity of the above mentioned massive galaxies, their r-band absolute magnitudes, their effective radii, and their luminosities are in the ranges -15.6 < ∼ M r < ∼ -7.8, 160 pc < ∼ R e < ∼ 4.1 kpc, and 0.1 × 10 6 < ∼ L L r < ∼ 127 × 10 6 , respectively. To determine whether these LSB galaxies are indeed satellites of the above mentioned massive galaxies, their distances need to be determined via further observations. Conclusions. Using small telescopes, we are readily able to detect LSB galaxies with similar properties to the known dwarf galaxies of the Local Group.

This paper, Part 2 of the Galactic Gravitational Field Measurements series, focuses on one of the most critical mechanisms in the Q-Epsilon framework: the transfer of energy and information from black holes into the Q-Epsilon field, where it becomes the source of gravitational curvature and structural organization throughout the galaxy.

Building directly on Part 1 – Galaxy Structuring & Dark Matter, which demonstrated that galactic rotation curves and spiral structure can be modeled as emergent outcomes of energy resonance and curvature (without the need for dark matter), this installment explores what happens at the center—inside the black hole.

Instead of treating black holes as singularities or endpoints, this paper presents them as active field interfaces that receive, modulate, and transmit energy into Q-Epsilon, shaping the field geometry responsible for observed galactic behavior. It introduces a reformulated black hole structure, the Môr MetriK, which replaces singularity-based reasoning with smooth resonance-based transition zones, governed by non-iterative collapse equations derived from the UMEC framework.

All modeling is consistent with quantum mechanics and general relativity but extends beyond both by treating wavefunction collapse, tunneling, and quantum behavior as resonance-based energy geometry, rather than probabilistic abstraction.

Together with foundational works such as Gravitational Field Measurements, Introduction to Q-Epsilon through Quantum Mechanics, UMEC: Non-Iterative Mathematics, and Quantum Mechanics & General Relativity: The Emergence of Physics, this paper forms a key link in a broader framework: replacing speculative models with a computable, structured alternative to ΛCDM cosmology.

The upcoming Part 3 – Galaxy Clusters will scale this system beyond individual galaxies, showing how entire cluster networks, voids, and filamentary structures emerge from interacting Q-Epsilon fields, completing the transition from local gravitational modeling to a full cosmological framework.

We determine the intrinsic shapes and orientations of 27, 450 type I and II active galactic nucleus (AGN) galaxies in the spectroscopic sample of the Sloan Digital Sky Survey Data Release 7, by studying the distribution of projected axis ratios of AGN hosts. Our aim is to study possible alignments between the AGN and host galaxy systems (e.g. the accretion disc and the galaxy angular momentum) and the effect of dust obscuration geometry on the AGN type. We define control samples of non-AGN galaxies that mimic the morphology, colour, luminosity and concentration distributions of the AGN population, taking into account the effects of dust extinction and reddening. Assuming that AGN galaxies have the same underlying three-dimensional shape distribution as their corresponding control samples, we find that the spiral and elliptical type I AGN populations are strongly skewed toward face-on galaxies, while ellipticals and spirals type II AGN are skewed toward edge-on orientations. These findings rule out random orientations for AGN hosts at high confidence for type I spirals (δχ 2 ≈ 230) and type II ellipticals (δχ 2 ≈ 15), while the signal for type I ellipticals and type II spirals is weaker (δχ 2 ≈ 3 and δχ 2 ≈ 6, respectively). We obtain a much stronger tendency for the type II spirals to be edge-on when just high [OIII] equivalent width (EW) AGN are considered, suggesting that > 20% of low [OIII] EW edge-on type II AGN may be missing from the optical sample. Galactic dust absorption of the broad-line region alone cannot explain the observed inclination angle and projected axis ratio distributions of type I and II Seyfert types, implying that obscuration by a small-scale circumnuclear torus is necessary. These results favour a scenario in which the angular momentum of the material which feeds the black hole retains a memory of its original gas source at least to some small, non-negligible degree.

We identify close pairs of galaxies from 278 deg 2 of Sloan Digital Sky Survey commissioning imaging data. The pairs are drawn from a sample of 330,041 galaxies with 18 < r * < 20. We determine the angular correlation function of galaxy pairs, and find it to be stronger than the correlation function of single galaxies by a factor of 2.9 ± 0.4. The two correlation functions have the same logarithmic slope of 0.77. We invert Limber's equation to estimate the three-dimensional correlation functions; we find clustering lengths of r 0 = 4.2 ± 0.4 h -1 Mpc for galaxies and 7.8 ± 0.7 h -1 Mpc for galaxy pairs. These results agree well with the global richness dependence of the correlation functions of galaxy systems.

The clustering of galaxies relative to the underlying mass distribution declines with cosmic time for three reasons. First, nonlinear peaks become less rare events as the density field evolves. Second, the densest regions stop forming new galaxies because their gas becomes too hot to cool and collapse. Third, after galaxies form, they are subject to the same gravitational forces as the dark matter, and thus they tend to trace the dark matter distibution more closely with time; in this sense, they are gravitationally "debiased." In order to illustrate these effects, we perform a large-scale hydrodynamic cosmological simulation of a ΛCDM model with Ω 0 = 0.37 and examine the statistics of δ * (r, z), the density field of recently formed galaxies at position r and redshift z. We find that the bias of recently formed galaxies b * ≡ δ 2 * 1/2 / δ 2 1/2 , where δ is the mass overdensity, evolves from b * ∼ 4.5 at z = 3 to b * ∼ 1 at z = 0, on 8 h -1 Mpc comoving scales. The correlation coefficient r * ≡ δδ * / δ 2 1/2 δ 2 * 1/2 evolves from r * ∼ 0.9 at

This paper represents the first in a multi-part series extending the methods introduced in Gravitational Field Measurements (Energy-Based) into the galactic regime. It provides a novel, testable alternative to the dark matter hypothesis by reinterpreting galactic rotation curves and gravitational lensing as emergent outcomes of structured energy flow within the Q-Epsilon field. Using the principles of UMEC (Universal Mathematical Extraction Computation), introduced in UMEC - Non-Iterative Computation by Pan, the paper models galaxies not as mass-bound systems requiring invisible matter, but as dynamically sustained energy flow networks centered on supermassive black holes.

Part 1 focuses on spiral galaxy structure, identifying spiral arms as coherent energy waveguides that transmit over 90% of the total galactic energy flow. The paper introduces the concept of the Low Resistance Zone (LRZ) at galactic boundaries—a region of heightened space-time elasticity that enables flat rotation curves without requiring unseen mass. This directly challenges dark matter halo models, offering a more parsimonious, energy-based explanation for persistent galactic dynamics.

The framework builds on foundational ideas from Introduction to Q-Epsilon through Quantum Mechanics, which redefines quantum behavior as structured energy modulation within Q-Epsilon, and Quantum Mechanics & General Relativity: The Emergence of Physics (formerly titled New Foundation for Understanding Reality), which unifies gravity, quantum mechanics, and energy modulation through a common resonance-based model. Part 1 applies these principles to large-scale cosmic structures, modeling galaxies as open resonant systems rather than gravitationally closed bodies.

As the opening paper in the Galactic Gravitational Field Measurements series, this work sets the stage for Part 2’s detailed modeling of black hole-Q-Epsilon coupling and Part 3’s cluster-scale gravitational dynamics. Together, these papers form the Galactic Energy Flow Framework, a comprehensive and scalable alternative to the ΛCDM cosmological model.

This paper investigates the evolving World View of our Universe from geo-centric to helio-centric to primary-centric World View . In the Copernican Framework, Kepler’s Third Law places no restriction on the orbit of a secondary. In Primary Centric Framework there are two Clarke’s Orbits which are non-dissipative and equilibrium orbits called inner and outer Clarke’s Orbit equivalent to geo-synchronous orbit in Earth-Moon System.  Outer Clarke’s Orbit is permissible as a stable orbit if the mass ratio of secondary to primary is greater than 0.2, Inner Clarke’s Orbit is permissible if mass ratio is less than 10-4 . If the mass ratio is between 10-4 to 0.1 then secondary spirals-out from inner Clarke’s Orbit to outer Clarke’s Orbit in super-synchronous condition and  spirals-in if it is in sub-synchronous orbit destined to be destroyed by the primary or if the secondary is not stiff enough it gets tidally pulverized within Roche’s limit of the primary into a ring around the primary. The Author conjecture states that every cosmological sub-system has a characteristic Primary Component anchoring the given sub-system and this primary decides the stable equilibrium orbits of the secondary/secondaries. Planet-Satellite has a Planet as the primary, Solar System and exo-Solar Systems have a planet hosting star(PHS) as the primary, Galaxy has a Super-Massive Black Hole(SMBH) as the primary, Cluster has a cD galaxy (central dominant Galaxy) which is also known as Brightest Cluster Galaxy(BCG) as the primary, Super-Cluster has a massive Cluster hosting a QUASER/Blazer as the primary. This goes ad-infinitum until a Cosmic Web is woven with Cosmic filaments. This conjecture gains a definite credence after the recent discoveries of the  over-massive Black Holes in  Galaxies namely Messier 87 in Virgo Cluster, NGC 3842 in Leo Cluster, NGC 4889 in Coma Cluster and NGC 1277 in Perseus Cluster. In 2011, a group of floating planets have been discovered. This is a transitory event and is an exception to this conjecture.

This paper presents an algebraic framework that integrates recursive expansive dynamics, fractal geometry, and non-Archimedean corrections through the introduction of novel constructs such as the Inverse Zero Operator (IZO) and Influence Operators. This theory models complex physical systems where interactions are influenced by prior states and semi-SUSY-recursive feedback mechanisms. The framework addresses spacetime propagation, energy dissipation, and information storage mechanisms in higher-dimensional structures. Theoretical foundations are established through geometric templates like trochoids epicycloids, hypocycloids, and HyperLimacon caustics. Constructed through fixed-point theorems, metric deformations, holographic entropy scaling. Hyperaddition and Hypermultiplication are defined with correction functions that incorporate fractal scaling and p-adic effects. We then build a layered model that smoothly transitions from quantum-scale operations (using Jordan algebras) to macroscopic feedback (modeled via loops and near-rings). Finally, we integrate these ideas with adelic Gromov-Witten theory and p-adic quantum geometry.

This study introduces the Negentropic Stabilization Index (NSI) as a novel framework for modeling galactic dynamics. NSI is evaluated against MOND (Modified Newtonian Dynamics) and classical Newtonian gravity by analyzing the rotation curves of spiral galaxies such as NGC 3198 and the Milky Way. The model incorporates an entropy-based stabilizing potential that captures core dynamics without invoking dark matter. Comparative results include MSE-based performance metrics, correlation heatmaps with baryonic surface density (R² = 0.63), and visualized rotation curves. The findings suggest NSI provides a physically grounded and statistically consistent alternative to existing paradigms. This dataset includes the full LaTeX article, statistical results in CSV format, rotation curve plots, and supporting heatmaps.

Quantum modification of general relativity (Qmoger) is supported by cosmic data (without fitting). Qmoger equations consist of Einstein equations with two additional terms responsible for production/absorption of matter. In Qmoger cosmology there was no Big Bang and matter is continuously producing by the Vacuum. Particularly, production of the ultralight gravitons with possible tiny electric dipole moment was started about 284 billion years ago. Quantum effects dominate interaction of these particles and they form the quantum condensate. Under influence of gravitation, the condensate is forming galaxies and producing ordinary matter, including photons. As one important result of this activity, it recently created us, the people, and continues to support us. Particularly, our subjective experiences (qualia) are a result of an interaction between the background condensate and the neural system of the brain. The action potentials of neural system create traps and coherent dynamic patt...

This paper presents a comprehensive framework for understanding physical reality through a revitalized Aether concept, demonstrating its capacity to unify quantum phenomena, gravitational interactions, and conscious observation. We formulate the Aether as a turbulent, fractal medium described by quaternionic flow fields (Φ = 𝐸 + 𝑖𝐵), where electromagnetic components emerge as orthogonal projections and gravity arises from radial pressure gradients (𝐺 =-∇ ⋅ Φ). Key innovations include: (1) A deterministic resolution to quantum "weirdness" via Aethermediated measurement interactions, (2) Derivation of mass as an

Precision measurements by the Alpha Magnetic Spectrometer on the International Space Station of the primary cosmic-ray electron flux in the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500 GeV are presented. The electron flux and the positron flux each require a description beyond a single power-law spectrum. Both the electron flux and the positron flux change their behavior at ∼30  GeV but the fluxes are significantly different in their magnitude and energy dependence. Between 20 and 200 GeV the positron spectral index is significantly harder than the electron spectral index. The determination of the differing behavior of the spectral indices versus energy is a new observation and provides important information on the origins of cosmic-ray electrons and positrons.

We present the first estimate of age, stellar metallicity and chemical abundance ratios, for an individual early-type galaxy at high-redshift (z = 1.426) in the COSMOS (Cosmological Evolution Survey) field. Our analysis is based on observations obtained with the X-Shooter instrument at the Very Large Telescope (VLT), which cover the visual and near-infrared spectrum at high (R > 5000) spectral resolution. We measure the values of several spectral absorptions tracing chemical species, in particular magnesium and iron, besides determining the age-sensitive D4000 break. We compare the measured indices to stellar population models, finding good agreement. We find that our target is an old (t > 3 Gyr), high-metallicity ([Z/H] > 0.5) galaxy which formed its stars at z form >5 within a short time-scale ∼0.1 Gyr, as testified by the strong [α/Fe] ratio (>0.4), and has passively evolved in the first >3-4 Gyr of its life. We have verified that this result is robust against the choice and number of fitted spectral features, and stellar population model. The result of an old age and high-metallicity has important implications for galaxy formation and evolution confirming an early and rapid formation of the most massive galaxies in the Universe.

After a brief review of the Decreasing Universe (D.U.) model, we will derive a formula and the graph for the apparent velocity of stars (of a Messier_33 galaxy) as a function of their radial distance from the galactic center. This formula reproduces the same velocity curve traditionally attributed to dark matter.

Current observations suggest that the reionisation of hydrogen in the intergalactic medium had begun by z ∼ 10 and was completed around z ∼ 6. Directly observing this epoch is not possible with existing instrumentation, making it difficult to infer how the increased ionising background during this period affected galaxy formation. This thesis aims to put constraints on the galaxy formation history of the Universe with existing instruments, by modelling and observing the number densities of observed Lyα emitters in the ionised environments around z ∼ 2 − 3 quasars to mimic conditions found during the epoch of reionisation. The main work presented is a model for the ionisation state of the intergalactic medium around star forming galaxies in the vicinity of a luminous quasar, tuned by empirical relationships from conditions at z ∼ 2 − 3. This model suggests that the intense ionising radiation from a quasar offsets the increased density of the intergalactic medium found around it, impl...

We present a new distance estimation method for dust-continuum-identified molecular cloud clumps. Recent (sub-)millimeter Galactic plane surveys have cataloged tens of thousands of these objects, plausible precursors to stellar clusters, but detailed study of their physical properties requires robust distance determinations. We derive Bayesian distance probability density functions (DPDFs) for 770 objects from the Bolocam Galactic Plane Survey in the Galactic longitude range 7. • 5 ≤ ℓ ≤ 65 • . The DPDF formalism is based on kinematic distances, and uses any number of external data sets to place prior distance probabilities to resolve the kinematic distance ambiguity (KDA) for objects in the inner Galaxy. We present here priors related to the mid-infrared absorption of dust in dense molecular regions and the distribution of molecular gas in the Galactic disk. By assuming a numerical model of Galactic mid-infrared emission and simple radiative transfer, we match the morphology of (sub-)millimeter thermal dust emission with mid-infrared absorption to compute a prior DPDF for distance discrimination. Selecting objects first from (sub-)millimeter source catalogs avoids a bias towards the darkest infrared dark clouds (IRDCs) and extends the range of heliocentric distance probed by mid-infrared extinction and includes lower-contrast sources. We derive well-constrained KDA resolutions for 618 molecular cloud clumps, with approximately 15% placed at or beyond the tangent distance. Objects with mid-infrared contrast sufficient to be cataloged as IRDCs are generally placed at the near kinematic distance. Distance comparisons with Galactic Ring Survey KDA resolutions yield a 92% agreement. A face-on view of the Milky Way using resolved distances reveals sections of the Sagittarius and Scutum-Centaurus Arms. This KDA-resolution method for large catalogs of sources through the combination of (sub-)millimeter and mid-infrared observations of molecular cloud clumps is generally applicable to other dust-continuum Galactic plane surveys.

Observational studies are increasingly finding evidence against major mergers being the dominant mechanism responsible for triggering an active galactic nucleus (AGN). After studying the connection between major mergers and AGNs with the highest Eddington ratios at z = 2, we here expand our analysis to , exploring the same AGN parameter space. Using ESO VLT/FORS2 , , and color images, we examine the morphologies of 17 galaxies hosting AGNs with Eddington ratios , and 25 mass- and redshift-matched control galaxies. To match the appearance of the two samples, we add synthetic point sources to the inactive comparison galaxies. The combined sample of AGN and inactive galaxies was independently ranked by 19 experts with respect to the degree of morphological distortion. We combine the resulting individual rankings into multiple overall rankings, from which we derive the respective major merger fractions of the two samples. With a best estimate of f m,agn = 0.41 ± 0.12 for the AGN host ga...

Moh. Fahry Djuraini (451419002) Aprilia I. Kasim (451419012) PROGRAM STUDI PENDIDIKAN GEOGRAFI JURUSAN ILMU DAN TEKNOLOGI KEBUMIAN FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM UNIVERSITAS NEGERI GORONTALO 2021 i KATA PENGANTAR Puji syukur kami panjatkan kehadirat Allah SWT yang telah memberikan rahmat serta hidayah kepada kita semua, sehingga berkat Karunia-Nya kami dapat menyelesaikan makalah Mata Kuliah Kosmografi. Makalah ini berisikan tentang materi dari Galaksi. Harapan kami, makalah ini dapat meningkatkan pemahaman kami akan ilmu-ilmu sosial budaya didalam masyarakat dan dapat diterapkannya dalam kehidupan sehari-hari. Tentunya dalam penyusunan makalah ini tidak terlepas dari berbagai pihak yang telah banyak membantu. Oleh karena itu kami mengucapkan terimakasih banyak kepada pihak yang telah membantu dalam menyelesaikan makalah ini. Kami menyadari bahwa makalah ini tidaklah sempurna, oleh karena itu kami menerima Kritik dan saran dari semua pihak yang bersifat membangun. Selalu kami harapkan demi kesempurnaan makalah ini serta guna penyempurnaan pembuatan makalah selanjutnya. Semoga makalah ini memberikan manfaat bagi kita semua.

photometric performances, estimated basing on the stellar populations crucial for understanding the formation and evolution of the Galaxy, are discussed. Performance of the GAIA photometric systems (PSs) is evaluated taking into account their ability to simultaneously determine the main stellar parameters: T eff , log g, [M/H], and E B-V , for a large variety of stars down to V ∼ 20. A sample of the stars (Photometric System Test Targets, PSTTs) applicable for evaluation of the GAIA photometric systems is presented. Definitions of the 1X PS and its accuracies of stellar parameterization are given. We conclude that there is still no photometric system, which would allow to achieve the scientific objectives of the GAIA mission at the limiting magnitude V = 20, proposed to date.

We present high resolution, multiwavelength continuum and molecular line images of the massive star-forming region IRAS 18317-0757. The global infrared through millimeter spectral energy distribution can be approximated by a two temperature model (25K and 63K) with a total luminosity of approximately log(L/L ⊙ ) = 5.2. Previous submillimeter imaging resolved this region into a cluster of five dust cores, one of which is associated with the ultracompact H II region G23.955+0.150, and another with a water maser. In our new 2.7mm continuum image obtained with BIMA, only the UCH II region is detected, with total flux and morphology in good agreement with the free-free emission in the VLA centimeterwave maps. For the other four objects, the non-detections at 2.7mm and in the MSX mid-infrared bands are consistent with cool dust emission with a temperature of 13-40K and a luminosity of 1000-40000 L ⊙ . By combining single-dish and interferometric data, we have identified over two dozen virialized C 18 O cores in this region which contain ≈ 40% of the total molecular gas mass present. While the overall extent of the C 18 O and dust emission is similar, their emission peaks do not correlate well in detail. At least 11 of the 123 infrared stars identified by 2MASS in this region are likely to be associated with the star-forming cluster. Two of these objects (both associated with UCH II) were previously identified as O stars via infrared spectroscopy. Most of the rest of the reddened stars have no obvious correlation with the C 18 O cores or the dust continuum sources. In summary, our observations indicate that considerable fragmentation of the molecular cloud has taken place during the time required for the UCH II region to form and for the O stars to become detectable at infrared wavelengths. Additional star formation appears to be ongoing on the periphery of the central region where up to four B-type (proto)stars have formed amongst a substantial number of C 18 O cores.

The intracluster medium (ICM) is a multi-phase environment, dynamically regulated by active galactic nuclei (AGN), the motions of cluster galaxies, and mergers with other clusters or groups. AGN provide a central heating source capable of preventing runaway cooling flows and quenching star formation, but how they achieve this is still poorly understood. We investigate the effects of AGN feedback and mergers on the ICM using the high-resolution RomulusC cosmological simulation of a 10 14 M galaxy cluster. We demonstrate that AGN feedback regulates and quenches star formation in the brightest cluster galaxy gently, without any explosive episodes, and co-exists with a low entropy core with sub-Gyr cooling times. In contrast, the merger disrupts the ICM structure, heating the core and cutting off the supply of low-entropy, infalling gas that until then fuelled the AGN. We find that this removal of the low-entropy phase correlates with the ratio t cool / t ff increasing above 30 in the core, matching observations that cooling gas is only found in clusters where this ratio is 5-30. Importantly, we find that evolution in the inner entropy profile and the ratio of cooling to free-fall timescale are directly connected to the quenching of star formation in the BCG. This is in line with previous results from idealized simulations and confirmed here within a fully cosmological simulation for the first time.

The majority of the ordinary matter in the local Universe has been heated by strong structure formation shocks and resides in a largely unexplored hot, diffuse, X-ray emitting plasma that permeates the halos of galaxies, galaxy groups and clusters, and the cosmic web. We propose a next-generation "Cosmic Web Explorer" that will permit a complete and exhaustive understanding of these unseen baryons. This will be the first mission capable to reach the accretion shocks located several times farther than the virial radii of galaxy clusters, and reveal the out-of-equilibrium parts of the intra-cluster medium which are live witnesses to the physics of cosmic accretion. It will also enable a view of the thermodynamics, kinematics, and chemical composition of the circumgalactic medium in galaxies with masses similar to the Milky Way, at the same level of detail that Athena will unravel for the virialized regions of massive galaxy clusters, delivering a transformative understanding of the evolution of those galaxies in which most of the stars and metals in the Universe were formed. Finally, the proposed X-ray satellite will connect the dots of the large-scale structure by mapping, at high spectral resolution, as much as 100% of the diffuse gas hotter than 10 6 K that fills the filaments of the cosmic web at low redshifts, down to an over-density of 1, both in emission and in absorption against the ubiquitous cosmic X-ray background, surveying at least 1600 square degrees over 5 years in orbit. This requires a large effective area (∼10 m 2 at 1 keV) over a large field of view (∼ 1 deg 2 ), a megapixel cryogenic microcalorimeter array providing integral field spectroscopy with a resolving power E/∆E = 2000 at 0.6 keV and a spatial resolution of 5 in the soft X-ray band, and a low and stable instrumental background ensuring high sensitivity to faint, extended emission. Keywords large-scale structure • clusters of galaxies • circumgalactic medium • warm-hot intergalactic medium

Achieving a precise understanding of galaxy formation in a cosmological context is one of the great challenges in theoretical astrophysics, due to the vast range of spatial scales involved in the relevant physical processes. Observations in the millimeter bands, particularly those using the cosmic microwave background (CMB) radiation as a "backlight", provide a unique probe of the thermodynamics of these processes, with the capability to directly measure the density, pressure, and temperature of ionized gas. Moreover, these observations have uniquely high sensitivity into the outskirts of the halos of galaxies and clusters, including systems at high redshift. In the next decade, the combination of large spectroscopic and photometric optical galaxy surveys and widefield, low-noise CMB surveys will transform our understanding of galaxy formation via these probes.

The Las Campanas Distant Cluster Survey (LCDCS), which contains over 1000 cluster candidates at z>0.3, is a unique sample with which to probe the evolution of both cluster galaxies and the properties of the cluster population. Programs are now underway to utilize the LCDCS for both purposes. We provide a brief overview of these programs, and also present new results for the LCDCS cluster correlation function. Utilizing well-defined, approximately dispersion-limited subsamples, we measure the angular correlation function for clusters at z≈0.5. Spatial correlation lengths are then derived via Limber inversion. We find that the correlation length depends upon mass, as parameterized by the mean cluster separation, in a manner that is consistent with both local observations and CDM predictions for the clustering strength at z=0.5.

We propose a new theoretical framework, Quantum Entropic Repulsion (QER), as a fundamental driver of cosmic expansion. Unlike dark energy models that assume a cosmological constant (\(\Lambda\)), QER posits that the universe expands due to an emergent entropic force arising from the growth of quantum entanglement entropy. We derive a modified Friedmann equation incorporating entanglement entropy and demonstrate how QER naturally explains the observed acceleration of the universe. This model solves the Hubble tension problem and replaces dark energy with quantum reality. QER remains consistent from the singularity to present day and to the late stages of the Universe where radiation dominates.

We present the discovery of a candidate of giant radio-quiet Lyα blob (RQLAB) in a large-scale structure around a high-redshift radio galaxy (HzRG) lying in a giant Lyα halo B3 J2330+3927 at redshift z = 3.087. We obtained narrow-and broad-band imaging around B3 J2330+3927 with Subaru/Suprime-Cam to search for Lyα emitters (LAEs) and absorbers (LAAs) at redshift z = 3.09 ± 0.03. We detected candidate 127 LAEs and 26 LAAs in the field of view of 31 × 24 arcmin 2 (58 × 44 comoving Mpc). We found that B3 J2330+3927 is surrounded by a 130 kpc Lyα halo and a large-scale (∼60 × 20 comoving Mpc) filamentary structure. The large-scale structure contains one prominent local density peak with an overdensity of greater than 5, which is 8 arcmin (15 comoving Mpc) away from B3 J2330+3927. In this peak, we discovered a candidate 100 kpc RQLAB. The existence of both types of Lyα nebulae in the same large-scale structure suggests that giant Lyα nebulae need special large-scale environments to form. On smaller scales, however, the location of B3 J2330+3927 is not a significant local density peak in this structure, in contrast to the RQLAB. There are two possible interpretations of the difference of the local environments of these two Lyα nebulae. First, RQLAB may need a prominent (δ ∼ 5) density peak of galaxies to form through intense starbursts due to frequent galaxy interactions/mergers and/or continuous gas accretion in an overdense environment. On the other hand, Lyα halo around HzRG may not always need a prominent density peak to form if the surrounding Lyα halo is mainly powered by its radio and active galactic nucleus activities. Alternatively, both RQLAB and Lyα halo around HzRG may need prominent density peaks to form but we could not completely trace the density of galaxies because we missed evolved and dusty galaxies in this survey.

We report the first result of a supernova search program designed to measure the evolution of the supernova rate with redshift. To make the comparison with local rates more significant we copied, as much as possible, the same computation recipes as for the measurements of local rates. Moreover, we exploited the multicolor images and the photometric redshift technique to characterize the galaxy sample and accurately estimate the detection efficiency. Combining our data with the recently published measurements of the SN Ia rate at different redshifts, we derived the first, direct measurement of the core collapse supernova rate at z = 0.26 as r cc = 1.45 +0.55 -0.45 h 2 SNu [h = H 0 /75]. This is a factor of three (±50%) larger than the local estimate. The increase for a look back time of 2.8 Gyr is more rapid than predicted by most of the published models of SN rate evolution. Core-collapse SN rates measure the death rate of massive stars and, because of the short time scale of evolution, can be translated into a measurement of the ongoing SFR. Assuming a Salpeter IMF and the standard scenario for core-collapse progenitors we derived an estimate of the star formation rate at redshift 3.1 +1.1 -1.0 × 10 -2 h 3 M yr -1 Mpc -3 which compares very well with a recent estimate based on the measurement of the Hα luminosity density at the same redshift.

This paper presents significant developments in cosmological theory, synthesizing insights from the Energy Flow and Grid-Higgs models. Detailed statistical analyses (ACT, WMAP data) o er empirical support, providing a compelling alternative to traditional cosmological assumptions.

Key findings include redefining dark matter and dark energy through entropy-driven energy flow dynamics, identifying the Higgs field as structural regulators of spacetime, and interpreting the cosmic microwave background (CMB) as a dynamic energy recycling process rather than a static relic of a singular event.

3C 400.2 is a supernova remnant (SNR) with a complex morphology consisting of two overlapped shells of different diameters: a large shell at the southeast and a small shell at the northwest. High-resolution radio-continuum observations carried out by Dubner et al. (1994) suggested that this complex morphology could be due to the interaction of two SNRs. However, this view has been challenged by recent studies of the H I distribution around this SNR (Giacani et al. 1998) and by the confrontation of theoretical evolutionary models with the morphology at H alpha of this remnant (Velazquez et al. 2001). These recent results suggest that the double shell structure is produced by a single supernova explosion initially expanding into a dense medium encountering a lower density medium and producing a blowout. In this work we present the results of H alpha Fabry-Perot observations obtained with the PUMA equipment at the 2.1 m telescope of the Observatorio Astronómico Nacional at San Pedro Má...

We present Globular Cluster Luminosity Functions for four ellipticals and one S0-Galaxy in the Fornax cluster of galaxies, derived from CCD photometry in V and I. The averaged turnover magnitudes are V T O = 23.80 ± 0.06 mag and I T O = 22.39 ± 0.05 mag, respectively. We derive a relative distance modulus (m -M ) F ornax -(m -M ) M87 = 0.08 ± 0.09 mag using the turnover of M87 based on HST data.

ABSTRACTUnderstanding quenching mechanisms in low-mass galaxies is essential for understanding galaxy evolution overall. In particular, isolated galaxies are important tools to help disentangle the complex internal and external processes that impact star formation. Comparisons between quenched field and satellite galaxies in the low-mass regime offer a substantial opportunity for discovery, although very few quenched galaxies with masses below $M_{\star }\, \sim \, 10^{9} {\rm M}_{\odot }$ are known outside the virial radius, Rvir, of any host halo. Importantly, simulations and observations suggest that an in-between population of backsplash galaxies also exists that may complement interpretations of environmental quenching. Backsplash galaxies – like field galaxies – reside outside the virial radius of a host halo, but their star formation can be deeply impacted by previous interactions with more massive systems. In this paper, we report the concurrent discovery of a low-mass ($M_{...

The front page illustrates the essence of this work, under the directives given by the University Design Guidelines, which seem to be very preoccupied with bubbles. The lower bubble displays a snapshot from a cosmological simulation at the time when the Universe was two and a half billion years old. The region is some 13 million lightyears across. Roughly one thousand galaxies float around in this volume, organized in beautiful filamentary structures, separated by huge voids of nothingness. Zooming in on one of the little dots, the middle bubble shows a pencil drawing of a few galaxies, slightly smeared out with my finger to create the effect of gaseous nebulae, and subsequently color-inverted. The upper bubble shows the closest zoom-in, symbolizing the fact that this work is predominantly numerical. In the simulations, the physical properties of the galaxies are represented by millions of numbers arranged in a threedimensional irregular matrix of cells. Two different projections of this matrix are shown in red and cyan, respectively, generating an anaglyph image which can be viewed with a pair of 3D glasses (although in the printed version the cyan may come out a bit too dark). In between the cells is seen a few lines from the computer code.

We have initiated a survey using the newly commissioned X-shooter spectrograph to target candidate relatively metal-rich damped Lyα absorbers (DLAs). Our rationale is that highmetallicity DLAs due to the luminosity-metallicity relation likely will have the most luminous galaxy counterparts. In addition, the spectral coverage of X-shooter allows us to search for not only Lyα emission, but also rest-frame optical emission lines. We have chosen DLAs where the strongest rest-frame optical lines ([O II], [O III], Hβ and Hα) fall in the nearinfrared atmospheric transmission bands. In this first paper resulting from the survey, we report on the discovery of the galaxy counterpart of the z abs = 2.354 DLA towards the z = 2.926 quasar Q 2222-0946. This DLA is amongst the most metal-rich z > 2 DLAs studied so far at comparable redshifts and there is evidence for substantial depletion of refractory elements on to dust grains. We measure metallicities from Zn II, Si II, Ni II, Mn II and Fe II of -0.46 ± 0.07, -0.51 ± 0.06, -0.85 ± 0.06, -1.23 ± 0.06 and -0.99 ± 0.06, respectively. The galaxy is detected in the Lyα, [O III] λλ4959, 5007 and Hα emission lines at an impact parameter of about 0.8 arcsec (6 kpc at z abs = 2.354). Based on the Hα line, we infer a star formation rate of 10 M yr -1 , which is a lower limit due to the possibility of slit loss. Compared to the recently determined Hα luminosity function for z = 2.2 galaxies, the DLAgalaxy counterpart has a luminosity of L ∼ 0.1L * Hα . The emission-line ratios are 4.0 (Lyα/Hα) and 1.2 ([O III]/Hα). In particular, the Lyα line shows clear evidence for resonant scattering effects, namely an asymmetric, redshifted (relative to the systemic redshift) component and a much weaker blueshifted component. The fact that the blueshifted component is relatively weak indicates the presence of a galactic wind. The properties of the galaxy counterpart of this DLA are consistent with the prediction that metal-rich DLAs are associated with the most luminous of the DLA-galaxy counterparts.

As an idealized model of the effects of energy release by supernovae during galaxy formation, we consider an explosion at the center of a halo which forms at the intersection of filaments in the plane of a cosmological pancake by gravitational instability during pancake collapse. Such halos resemble the virialized objects found in N-body simulations in a CDM universe and, therefore, serve as a convenient, scale-free test-bed model for galaxy formation. ASPH/P3M simulations reveal that such explosions are anisotropic. The energy and metals are channeled into the low density regions, away from the pancake plane. The pancake remains essentially undisturbed, even if the explosion is strong enough to blow away all the gas located inside the halo at the onset of the explosion and reheat the IGM surrounding the pancake. Infall quickly replenishes this ejected gas and gradually restores the gas fraction as the halo mass continues to grow. Estimates of the collapse epoch and SN energy-releas...

This article extends the five-dimensional (5D) model of wave-particle duality presented in [1] by integrating gravitational effects through a curved 5D metric and a generalized Lorentz factor that accommodates frame-dependent light speed. The original framework interpreted quantum phenomena, such as wave-particle duality, as projections from a higher-dimensional spacetime with a variable speed of light. Here, we enhance this model by introducing gravity and modifying the Lorentz factor, providing a novel linkage between quantum mechanics, relativity, and gravitational physics. This approach suggests a potential pathway toward unifying these domains.

EMU is a wide-field radio continuum survey planned for the new Australian Square Kilometre Array Pathfinder (ASKAP) telescope. The primary goal of EMU is to make a deep (rms ∼ 10 μJy/beam) radio continuum survey of the entire Southern sky at 1.3 GHz, extending as far North as +30° declination, with a resolution of 10 arcsec. EMU is expected to detect and catalogue about 70 million galaxies, including typical star-forming galaxies up to z ∼ 1, powerful starbursts to even greater redshifts, and active galactic nuclei to the edge of the visible Universe. It will undoubtedly discover new classes of object. This paper defines the science goals and parameters of the survey, and describes the development of techniques necessary to maximise the science return from EMU.

We present a detailed study of a galaxy merger taking place at 𝑧 = 1.89 in the GOODS-S field. Here we analyze Keck/MOSFIRE spectroscopic observations from the MOSFIRE Deep Evolution Field (MOSDEF) survey along with multi-wavelength photometry assembled by the 3D-HST survey. The combined dataset is modeled to infer the past star-formation histories (SFHs) of both merging galaxies. They are found to be massive, with log 10 (𝑀 * /𝑀 ) > 11, with a close mass ratio satisfying the typical major-merger definition. Additionally, in the context of delayed-𝜏 models, GOODS-S 43114 and GOODS-S 43683 have similar SFHs and low star-formation rates (log 10 (SFR(SED)/𝑀 /yr -1 ) < 1.0) compared to their past averages. The best-fit model SEDs show elevated H𝛿 A values for both galaxies, indicating that their stellar spectra are dominated by A-type stars, and that star formation peaked ∼ 0.5 -1 Gyr ago and has recently declined. Additionally, based on SED fitting both merging galaxies turned on and shut off star formation within a few hundred Myr of each other, suggesting that their bursts of star formation may be linked. Combining the SFHs and H𝛿 A results with recent galaxy merger simulations, we infer that these galaxies have recently completed their first pericentric passage and are moving apart. Finally, the relatively low second velocity moment of GOODS-S 43114 given its stellar mass, suggests a disk-like structure. However, including the geometry of the galaxy in the modeling does not completely resolve the discrepancy between the dynamical and stellar masses. Future work is needed to resolve this inconsistency in mass.

We present a detailed study of a galaxy merger taking place at 𝑧 = 1.89 in the GOODS-S field. Here we analyze Keck/MOSFIRE spectroscopic observations from the MOSFIRE Deep Evolution Field (MOSDEF) survey along with multi-wavelength photometry assembled by the 3D-HST survey. The combined dataset is modeled to infer the past star-formation histories (SFHs) of both merging galaxies. They are found to be massive, with log 10 (𝑀 * /𝑀 ) > 11, with a close mass ratio satisfying the typical major-merger definition. Additionally, in the context of delayed-𝜏 models, GOODS-S 43114 and GOODS-S 43683 have similar SFHs and low star-formation rates (log 10 (SFR(SED)/𝑀 /yr -1 ) < 1.0) compared to their past averages. The best-fit model SEDs show elevated H𝛿 A values for both galaxies, indicating that their stellar spectra are dominated by A-type stars, and that star formation peaked ∼ 0.5 -1 Gyr ago and has recently declined. Additionally, based on SED fitting both merging galaxies turned on and shut off star formation within a few hundred Myr of each other, suggesting that their bursts of star formation may be linked. Combining the SFHs and H𝛿 A results with recent galaxy merger simulations, we infer that these galaxies have recently completed their first pericentric passage and are moving apart. Finally, the relatively low second velocity moment of GOODS-S 43114 given its stellar mass, suggests a disk-like structure. However, including the geometry of the galaxy in the modeling does not completely resolve the discrepancy between the dynamical and stellar masses. Future work is needed to resolve this inconsistency in mass.

We describe results from a search for high-redshift J-band "dropout" galaxies in the portion of the Great Observatories Origins Deep Survey (GOODS) southern field that is covered by extremely deep imaging from the Hubble Ultradeep Field (HUDF). Using observations at optical, near-infrared and mid-infrared wavelengths from the Hubble and Spitzer Space Telescopes and the European Southern Observatory Very Large Telescope, we find one particularly remarkable candidate, which we designate as HUDF-JD2. Its spectral energy distribution has distinctive features that are consistent with those of a galaxy at z ∼ 6.5,

In fitting galactic rotation curves to data, most standard theories make use of a single exponential disk approximation of the gas distribution to account for the HI synthesis data observed at various radio telescope facilities. We take a sample of surface brightness profiles from The HI Nearby Galaxy Survey (THINGS), and apply both single disk exponentials and Multi-Disk exponentials, and use these various models to see how the modelling procedure changes the Newtonian prediction of the mass of the galaxy. Since the missing mass problem has not been fully explained in large spiral galaxies, different modelling procedures could account for some of the missing matter.

Starting with a brief review of Born Reciprocal (Non-inertial) Relativity Theory (BRRT), it is shown how massless photons in one frame of reference can appear massive, even tachyonic, in an acccelerated frame. An immediate application can be found in the behavior of in-falling/outgoing photons propagating in a black hole gravitational background. When the in-falling photon gains energy one learns that (dτ ′)^2 > 0 such that the blue-shifted photon from the point of view of an accelerated frame of reference (with respect to a static spherically symmetric Schwarzschild black hole, for example) will appear massive and subluminal. However, when the outgoing photon loses energy one has (dτ ′)^2 < 0 and the red-shifted photon from the point of view of an accelerated frame will appear tachyonic and superluminal. This is an interesting physical feature because no particle (inside the horizon) can escape the interior of black hole unless it moves faster than light; i.e. it is tachyonic (superluminal). These effects may have important consequences in cosmology (dark energy, dark matter problem).

The capability of extremely large telescopes (ELTs) to resolve stellar populations in distant galaxies has been investigated through simulation. With real stellar clusters as templates, images were created using a realistic point spread function model. Through variation of parameters such as aperture, Strehl ratio and exposure, as well as use of various stellar populations and densities, we study ELT capability to probe galaxy formation and evolution history. We conclude that a 50m ELT should allow study of these processes in the Virgo galaxy cluster.

We present the imaging observations made with the Space Telescope Imaging Spectrograph of the Hubble Deep Field -South. The field was imaged in 4 bandpasses: a clear CCD bandpass for 156 ksec, a long-pass filter for 22-25 ksec per pixel typical exposure, a near-UV bandpass for 23 ksec, and a far-UV bandpass for 52 ksec. The clear visible image is the deepest observation ever made in the UV-optical wavelength region, reaching a 10σ AB magnitude of 29.4 for an object of area 0.2 square arcseconds. The field contains QSO J2233-606, the target of the STIS spectroscopy, and extends 50 × 50 for the visible images, and 25 × 25 for the ultraviolet images. We present the images, catalog of objects, and galaxy counts obtained in the field.

Deep, multiband observations of high Galactic latitude Ðelds are an essential tool for studying topics ranging from Galactic structure to extragalactic background radiation. The Hubble Deep Field (HDF-N) observations obtained in 1995 December established a standard for such narrow, deep surveys. The Ðeld has been extensively analyzed by a variety of groups and has been widely studied with imaging and spectroscopy over wavelengths ranging from 10~3 to 2 ] 105 km. We describe here a second deep Ðeld campaign (HDF-S), this time in the southern hemisphere, undertaken by the Hubble Space T elescope (HST ) in 1998 October in a program very similar to the northern Hubble Deep Field. Imaging and spectroscopy of three adjacent Ðelds in the southern continuous viewing zone were obtained simultaneously for 150 orbits, and a mosaic of Ñanking Ðelds was imaged for 27 additional orbits. Two important features of the HDF-S distinguish it from the HDF-N : the campaign included parallel observations by the three main HST instrumentsÈWFPC2, STIS, and NICMOSÈand the HDF-S location was selected to place a bright z \ 2.24 quasar in the STIS Ðeld of view. The HDF-S observations consist of WFPC2 images in Ðlters close to U, B, V , and I, a deep STIS image of the Ðeld surrounding the quasar, spectroscopy of the quasar with STIS from 1150 to 3560 and deep imaging of an adjacent Ðeld with Ó, NICMOS camera 3 at 1.1, 1.6, and 2.2 km. All of the HDF-S data were fully reduced and made publicly available within 2 months of the observations, and we describe here the selection of the Ðelds and the observing strategy that was employed. Detailed descriptions of the data and the reduction techniques for each Ðeld, together with the corresponding source catalogs, appear in separate papers.