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We present the New Online Database of Symbiotic Variables (NODSV), a comprehensive and publicly accessible catalog of known and candidate symbiotic stars in the Milky Way and nearby galaxies. The database provides an up-to-date census of confirmed symbiotic binaries and systematically compiles information previously scattered across the literature, including photometric and spectroscopic properties, orbital parameters, and characteristics of both their cool and hot stellar components. It further records auxiliary diagnostics such as detected emission lines, flickering, X-ray emission, jets, or information about outburst activity. In its current release, NODSV contains nearly 1400 objects, classified into confirmed symbiotic stars, three categories of candidates, and misidentified sources. Based on the collected data, though originating from heterogeneous studies, we present a statistical overview of the confirmed symbiotic population, highlighting the distributions of orbital parameters and the properties of the cool giants and their hot companions. Designed as a dynamic and evolving resource, NODSV provides a foundation for future observational campaigns and theoretical investigations of symbiotic binaries.

Gamma-ray-emitting narrow-line Seyfert 1 (γ-NLSy1) galaxies represent an enigmatic class of active galactic nuclei (AGNs) bridging populations of radio-quiet and radio-loud AGNs. Here we report the multi-wavelength investigation of a rare γ-ray flaring episode of an NLSy1 galaxy, 1H 0323+342 (<mml:math><mml:mrow><mml:mi>z</mml:mi><mml:mo>=</mml:mo><mml:mn>0.063</mml:mn></mml:mrow></mml:math>), using data from Fermi-Large Area Telescope, Swift, and Nuclear Spectroscopic Telescopic Array. The source exhibited a significant enhancement in γ-ray flux along with rapid variability on ∼ sub-hour timescales in both γ-ray and hard X-ray wavelengths, hinting that the energy dissipation is happening from a compact region close to the central supermassive black-hole. The time-resolved X-ray spectral study revealed a transition between a jet-dominated and a mixed jet+corona emission state. Reproducing the broadband spectral energy distribution with a one-zone leptonic model suggested that the high-energy emission is mainly produced by external Compton scattering of the accretion disc and broad line region (BLR) photons. The inferred jet power reaches values of the order of 10<SUP>46</SUP> erg s<mml:math><mml:msup><mml:mrow></mml:mrow><mml:mrow><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:math> comparable to those of powerful flat-spectrum radio quasars, suggesting that even low black-hole mass systems can occasionally produce powerful γ-ray outbursts.

Ultraviolet (UV) observations provide a uniquely powerful window into the hot and evolved stellar populations that shape the structure, evolution and integrated light of star clusters. Because UV wavelengths are highly sensitive to massive main-sequence stars, blue straggler stars (BSS), extreme-horizontal-branch (extreme-HB) stars, post-AGB objects, interacting binaries and compact remnants, UV studies enable constraints on fundamental processes that are inaccessible at optical and infrared wavelengths. This review synthesises five decades of UV investigations of star clusters across the Milky Way, the Magellanic Clouds (MCs) and nearby galaxies, drawing on results from early space telescopes, wide-field surveys, high-resolution imagers and the recent capabilities of AstroSat/UVIT and Swift/UVOT. In Galactic open clusters, UV photometry has revealed diverse compact companions—including white dwarfs, hot subdwarfs and stripped stars—and has been essential for establishing the mass-transfer origins of BSS and related populations such as Blue Lurkers and yellow stragglers. In globular clusters, UV imaging is indispensable for identifying multiple stellar populations through UV-sensitive molecular bands, probing helium enrichment and mapping HB morphologies from cluster cores to tidal radii. Wide-field UVIT surveys have provided homogeneous catalogues of HB and post-HB stars, extending earlier Hubble Space Telescope results to full-cluster scales. In the MCs, UV observations have transformed our understanding of multiple populations in intermediate-age clusters, rotation-driven extended main-sequence turn-offs and the recently identified UV-dim phenomenon. UV spectroscopic surveys have advanced constraints on massive-star evolution, winds and binarity at low metallicity. Meanwhile, UV mapping of the Magellanic Bridge demonstrates ongoing massive-star formation in low-density tidal environments. Beyond the Local Group, UV studies of extragalactic clusters reveal star-formation histories, stellar feedback and population synthesis constraints in diverse galactic environments. Collectively, UV observations now form a cornerstone of star cluster astrophysics and will continue to do so with upcoming missions.

The aim of the present work is two-fold: {\it(i)} Compute the drift of comoving extragalactic sources in axial Bianchi IX universes, in particular in those satisfying Einstein's equations with positive cosmological constant and comoving dust. {\it(ii)} Linearize this drift (and for comparison the previously calculated Lema{î}tre-Hubble diagram) simultaneously in small anisotropy and in small positive curvature. We find that the drift in this linear approximation coincides with the drift in axial Bianchi I universes. This is not true for Lema{î}tre-Hubble diagrams.

Neutrinos and dark energy (DE) have entered a new era of investigation, as the latest DESI baryon acoustic oscillation measurements tighten the constraints on the neutrino mass and suggest that DE may be dynamical rather than a cosmological constant. In this work, we obtain a high-confidence measurement of the neutrino mass within a dynamical DE framework. A joint analysis of DESI DR2, cosmic microwave background, DESY5 supernova, and DESY1 weak lensing data yields a total neutrino mass of <inline-formula><mml:math><mml:mo>∑</mml:mo><mml:msub><mml:mi>m</mml:mi><mml:mrow><mml:mi>ν</mml:mi></mml:mrow></mml:msub><mml:mo>=</mml:mo><mml:msubsup><mml:mn>0.098</mml:mn><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.037</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo><mml:mn>0.016</mml:mn></mml:mrow></mml:msubsup><mml:mspace></mml:mspace><mml:mtext>eV</mml:mtext></mml:math></inline-formula>, indicating a measurement for a non-zero, positive neutrino mass at the 2.7σ level within the w<SUB>0</SUB>w<SUB>a</SUB>CDM framework. This high-confidence measurement is driven mainly by these factors: (i) the DESI's preference for a dynamical DE with its equation of state evolving from w &lt; -1 at early times to w &gt; -1 at late times, thus leading to a larger neutrino mass; (ii) treating N<SUB>eff</SUB> as a free parameter together with the inclusion of weak lensing data, which likewise allows for an increased neutrino mass. In the future, even higher-confidence measurements of neutrino mass are expected with stronger preferences for dynamical DE in light of more complete DESI data releases.