Compact objects are of great interest in astrophysical research. There are active research interests in understanding better various aspects of formation and evolution of these objects. In this paper we addressed some problems related to the compact objects mass limit. We employed Einstein field equations (EFEs) to derive the equation of state (EoS). With the assumption of high densities and low temperature of compact sources, the derived equation of state is reduced to polytropic kind. Studying the polytropic equations we obtained similar physical implications, in agreement to previous works. Using the latest version of Mathematica-11 in our numerical analysis, we also obtained similar results except slight differences in accuracy.

We present the data related to the revealed astronomical oldest observatories at the territory of Ukraine and describe briefly the principles of observations which could be realized at these sites with usage of megalithic stones. Among these oldest observatories are as follows: the stone complex at the Lysyna Kosmatska mountain (Charpatian region); Bakhchysaray Menhir in Crimea; a complex of shafts at the Mavrin Maidan near Pavlograd city.

Silicate is the most popular dust species in the circumstellar envelope of evolved oxygen-rich stars, yet its seed particles have not been well identified. Among the candidates, corundum and SiO attract intense attention and study. SiO was suggested to be the seed particles in early 1980s and has received various supports as well as oppositions. In this work we investigate the relation of SiO maser and silicate dust emission powers. With both our own observation by using the PMO/Delingha 13.7-m telescope and the archival data, a sample is assembled of 21 SiO v=1, J=2-1 sources and 28 SiO v=1, J=1-0 sources that exhibit silicate emission features in the ISO/SWS spectrum. The analysis of their SiO maser and silicate emission power shows a moderate correlation, which agrees with the idea that SiO molecules are the seed nuclei of silicate dust.

Observations at high redshift reveal that a population of massive, quiescent galaxies (called red nuggets) already existed 10 Gyr ago. These objects undergo a significant size evolution over time, likely due to minor mergers. In this work we present an analysis of local massive compact galaxies to assess if their properties are consistent with what is expected for unevolved red nuggets (relic galaxies). Using integral field spectroscopy (IFS) data from the MaNGA survey from the Sloan Digital Sky Survey (SDSS), we characterized the kinematics and properties of stellar populations of massive compact galaxies, and find that these objects exhibit, on average, a higher rotational support than a control sample of average sized early-type galaxies. This is in agreement with a scenario in which these objects have a quiet accretion history, rendering them candidates for relic galaxies.

Resolved emission from gas-phase methanol can reveal the abundance and distribution of the comet-forming ice reservoir in protoplanetary disks. ALMA Cycle 4 observations of four transitions of gas-phase methanol in TW Hya allow the first model-independent determination of the rotational temperature of methanol in a prototoplanetary disk. The data confirm that the methanol is rotationally cold (Trot < 50 K), and well constrain the column density to 2 × 1012 cm−2. Astrochemical models will constrain the chemical origin of methanol in TW Hya.

Galaxy morphologies reflect the shapes of galaxies and their structural components, such as bulges, discs, bars, spiral arms, etc. The detailed knowledge of the morphology of a galaxy provides understanding of the physics behind its evolution, since the time of its formation, including interaction processes and influence of the environment. Thus, the more precisely we can describe a galaxy structure, the more we may understand about its formation and evolution. We present a method that measures curvature, using images, to describe galaxy structure and to infer the morphology of each component of a galaxy. We also include some preliminary results of curvature measurements for galaxies of the Southern Photometric Local Universe Survey (S-PLUS) DR1 data release and for jellyfish galaxies of the Omega Survey. We find that the median of the curvature parameter and the integrated area under the curvature give us clues on the morphology of a galaxy.

Astronomical observatory publications include the work of local astronomers from observatories around the world and are traditionally exchanged between observatories through their libraries. However, large collections of these publications appear to be rare and are often incomplete. In order to assess the unique properties of the collections, we compare observatories present in our own collection from the university at Copenhagen, Denmark with two collections from the USA: one at the Woodman Library at Wisconsin-Madison and another at the Dudley Observatory in Loudonville, New York.

Taking secondary particles produced from dark matter (DM) annihilation process to the origin of the extended diffuse radio emission observed in galaxy clusters, we studied both their morphology and radio spectral profile using simulated Coma like galaxy clusters. We have considered a neutralino annihilation channel dominated by $b\overline b $ species with a branching ratio of 1 and neutralino mass of 35 GeV with annihilation cross-section of 1×10-26 cm3 s-1. The radio emission maps produced for the two simulated galaxy clusters which are based on the MUsic SImulation of galaxy Clusters (MUSIC) dataset reveal the observed radio halo morphology showing radio emission both from the central regions of the cluster and substructures lying out off cluster centre. The flux density curve is in a good agreement for ν ≤ 2 GHz with the obsevational values for the Coma cluster of galaxies showing a small deviation at higher frequencies.

The formation of stars constitutes one of the basic problems in astrophysics. Understanding star formation efficiency of molecular clouds (MCs) of a galaxy is necessary for studying the galactic evolution. Present data and theoretical formulations show that the structure and dynamics of the interstellar medium (ISM) are extremely complex. Therefore, there is no simple model that can explain adequately the star formation efficiency of MCs because of its complex nature. The initial mass of the cloud needed for collapse varies based on the environment in which the cloud resides and the strength of its magnetic field, turbulence, as well as the speed of rotation. In this paper, we estimate the star formation efficiency by combining pre-determined models and the critical mass formulated by Kumssa & Tessema (2018).

Dark matter bars are structures that may form inside dark matter haloes of barred galaxies. Haloes can depart from sphericity and also be subject to some spin. The latter is known to have profound impacts on the evolution of both stellar and DM bars, such as stronger dynamical instabilities, more violent vertical bucklings and dissolution or impairment of stellar bar growth. On the other hand, dark matter bars of spherical haloes become initially stronger in the presence of spin. In this study, we add spin to triaxial halos in order to quantify and compare the strength of their bars. Using N-body simulations, we find that spin accelerates main instabilities and strengthens the halo bars, although their final strength depends only on triaxiality. The most triaxial halo barely forms a halo bar, showing that flattening opposes to DM bar strengthening and indicating that there is a limit on how flattened the parent structure can be.

In the context of the European Middle Ages as the period roughly covering from the 5th to the 15th centuries, the astronomical records are rarery found in scientific treatises. At least, not until the 15th century. A few surprinsing examples in which the observations were recorded in a particularly original way on stone are found. In this poster we will shortly review the only four cases in which this occurred in Europe.

Interstellar carbon has been detected in both gas-phase molecules and solid particles. The goal of this study is to identify the link between these two phases of cosmic carbon. Here we report preliminary results on the low temperature formation of carbonaceous dust grains from gas-phase aromatic hydrocarbon precursors. This is done using the supersonic expansion of an argon jet seeded with aromatic molecules and exposed to an electrical discharge. We report experimental evidence of efficient carbon dust condensation from aromatic molecules including benzene and naphthalene. The molecular content of the solid grains is probed with laser desorption mass spectrometry. The mass spectra reveal a rich molecular composition including fragments of the parent molecule but also growth into larger molecular species.

Multi-wavelength emission maps from dark matter (DM) annihilation processes in galaxy clusters are produced using Marenostrum-MultiDark SImulation of galaxy Clusters (MUSIC-2) high resolution cosmological simulations. Comparison made with observational radio emission flux data (spectral shape) and the spatial distribution from the simulated emission maps show that secondary particles from DM annihilation could describe the origin of energetic particles which are the sources of the diffuse radio emission observed in large number of galaxy clusters. DM sub-halos which are dominantly composed of DM, but with very little or no gas and stellar content, are ideal objects to study the nature and properties of DM. Therefore, statistical studies of a large number of them as well the emission maps of high mass-to-light ratio DM sub-halos will not only explain the observed diffused radio emission but also provide very crucial information about the nature and properties of DM particles.

We use quantum chemical techniques to model the vibrational spectra of small aromatic molecules on a proton-ordered hexagonal crystalline water ice (XIh) model. We achieve a good agreement with experimental data by accounting for vibrational anharmonicity and correcting the potential energy landscape for known failures of density functional theory. A standard harmonic description of the vibrational spectra only leads to a broad qualitative agreement.

Department of Astronomy, Kyoto University has been conducting astronomy outreach programs in Kyoto University Hospital since 2006. In this proceeding, we report our activities in the hospital, survey results from graduate students, and discuss future directions.

We present Gemini Near-Infrared Integral-Field Spectrograph (NIFS) observations of the inner 660 × 660 pc2 of the Seyfert 2 galaxy NGC 1125, which reveals that the emission-line profiles present two kinematic components: a narrow one (σ < 150 km s−1) due to emission of the gas in the disk and a broad component (σ > 150 km s−1) produced by a bipolar outflow, perpendicular to the galaxy’s disk.

The aim of this work is to explain the possible mechanism in the early Solar System, by which water-rich asteroids may have been delivered to Earth. Carbonaceous (C-type) asteroids, with a large fraction of water molecules, dominate in the outer part of the asteroid belt and the possibility of their migration toward Earth is still not well explained. In this work, we observe very efficient dynamical routes along which C-type water-bearing asteroids are delivered to Earth.

We report the results of 14 years of monitoring of G188.95+0.89 periodic 6.7 GHz methanol masers using the Hartebeesthoek 26-m radio telescope. G188.95+0.89 (S252, AFGL5180) is a radio-quiet methanol maser site that is often interpreted as precursors of ultra-compact HII regions or massive protostar sites. At least five bright spectral components were identified. The maser feature at 11.36 km s-1 was found to experience an exponential decay during the monitoring period. The millimetre continuum reveals two cores associated with the source.

We present the first results of the Deep Integral Field Spectroscopy View of Nuclei of Galaxies (DIVING3D) survey, obtained from the analysis of the nuclear emission-line spectra of a sub-sample we call mini-DIVING3D, including all southern galaxies with B < 11.2 and |b| >15°. In comparison with previous studies, very few galaxies were classified as Transition objects. A possible explanation is that at least part of the Transition objects are composite systems, with a central low-ionization nuclear emission-line region (LINER) contaminated by the emission from circumnuclear H II regions. The high spatial resolution of the DIVING3D survey allowed us to isolate the nuclear emission from circumnuclear contaminations, reducing the number of Transition objects.

The African Network of Women in Astronomy and STEM for GIRLS in Ethiopia initiatives have been established with aim to strengthen the participation of girls and women in astronomy and science in Africa and Ethiopia. We will not be able to achieve the UN Sustainable Development Goals without full participation of women and girls in all aspects of our society and without giving in future the same opportunity to all children to access education independently on their socio-economical status. In this paper both initiatives are briefly introduced.