An extended catalog of long-periodic terms of the Sun tide-generating potential (STGP ver.2) is released. It contains 2.5 times of such terms than in the first version of the STGP catalog (Cionco et al. 2023). The analysis of the new data is done in order to re-examine the existence of tidal forces of ≈ 11.0-yr and ≈ 22.0-yr period able to excite the observed solar-activity cycles. In several recent studies, such tidal forcings are claimed to be a result of certain combinations of Venus, Earth and Jupiter mean motions with the multipliers (6, −10, 4) and (3, −5, 2), respectively. So, in this contribution, we specifically look for the periodic terms related to these combinations. As a result of these additional investigation we do not confirm any noticeable tidal forcing factors of ≈ 11.0-yr nor ≈ 22.0-yr period in the extended STGP spectrum either.

According to many historical records, 1P/Halley comet was reported to appear in 760 AD. In the same year in Indonesia, the Dinoyo inscription told us the story of the Kanjuruhan kingdom which held a Vedic ceremony to purify a new shrine and statue of Agastya to repel enemy forces (or dispel the epidemic). Many traditions believe that the appearance of a comet is a sign of war, plague/epidemic, death, etc. By applying this understanding to the archaeoastronomical framework, the hypothesis is proposed, that the king’s order which was written on the inscription shows the response to the 1P/Halley comet appearance in 760 AD. There are three ways to examine the hypothesis: by testing the chronological, geographical, and cultural aspects. Through some literature studies and the Stellarium Astronomy Software simulation, the initial research found that the chronological and geographical aspects support the hypothesis.

Fundamental physical quantities of the nuclear regions of the Active Galactic Nuclei can be obtained using megamaser studies. In particular, disk-masers associated with accretion disks around the supermassive black holes are used, through high angular resolution measurements, to trace the disk geometry, to estimate the BH mass and to measure accurate distances to their host galaxies. In this contribution, we present the first results in continuum and spectral-line mode of a high-sensitivity, multi-epoch VLBI study of the nuclear region of the megamaser LINER galaxy IC 485.

Large scale optical and infrared surveys have revealed numbers of accretion-derived stellar features within the halo of the Galaxy. These coherent tail-like features are produced by encounters with satellite dwarf galaxies. We conducted an SiO and H2O maser survey towards O-rich AGBs towards the orbital plane of the Sgr Stellar Stream from 2016. Up to now, maser emissions have been found from 60 sources, most of which are detected for the first time. However, their distances and kinematics suggest they are still disk stars.

We discuss the role that coherence phenomena can have on the intensity variability of spectral lines associated with maser radiation. We do so by introducing the fundamental cooperative radiation phenomenon of (Dicke’s) superradiance and discuss its complementary nature to the maser action, as well as its role in the flaring behaviour of some maser sources. We will consider examples of observational diagnostics that can help discriminate between the two, and identify superradiance as the source of the latter. More precisely, we show how superradiance readily accounts for the different time-scales observed in the multi-wavelength monitoring of the periodic flaring in G9.62+0.20E.

Eight planetary nebulae (PNe) are known to emit OH and/or H2O masers, but there is no report of an SiO maser in this type of objects. We present a search for SiO masers in 16 confirmed and candidate PNe, carried out with the Australia Telescope Compact Array. We found no evidence of association between SiO masers and PNe in our data. Previous detections of thermal SiO emission in PNe show that these molecules can be present in gas phase in this type of objects, but it is not yet clear whether they can be found where the physical conditions are appropriate for maser pumping. We suggest that the best candidates for a new search would be PNe showing high-velocity outflows.

We present dual-frequency VLBI observations of a nearby radio galaxy NGC 4261 at 22 and 43 GHz using the East Asia VLBI Network. In particular, the first sub-pc scale image of the 22 GHz water megamaser line in the circumnuclear region of NGC 4261 is shown. Our results suggest that the megamaser emission in NGC 4261 can be associated with the inner radius of the obscuring disk, as it is proposed for the nearest radio-loud megamaser source NGC 1052. An alternative hypothesis on the megamaser association is the shock region of the interaction between the jet and ambient molecular clouds.

HINOTORI (Hybrid Integration Project in Nobeyama, Triple-band Oriented) has constructed a higher sensitivity 22/43 GHz and a 22/43/86 GHz simultaneous observation systems in the Nobeyama 45-m telescope by introducing new frequency separation filters in the telescope’s quasi-optics. The performance of the observation systems, such as the beam squint, the aperture efficiency, the system noise temperature when inserting the filters, and the phase stability of the signal path have been evaluated. It is indicated that the established systems have sufficient performance for single-dish and VLBI observations. The single-dish observation demonstrations using the triple-band system were successfully conducted in acquiring scientific data including multiple maser lines.

Galaxy-galaxy strong lensing in galaxy clusters is a unique tool for studying the subhalo mass distribution, as well as for testing predictions from cosmological simulations. We describe a novel method that simulates realistic lensed features embedded inside the complexity of observed data by exploiting high-precision cluster lens models. Such methodology is used to build a large dataset with which Convolutional Neural Networks have been trained to identify strong lensing events in galaxy clusters. In particular, we inject lensed sources around cluster members using the images acquired by the Hubble Space Telescope. The resulting simulated mock data preserve the complexity of observation by taking into account all the physical components that could affect the morphology and the luminosity of the lensing events. The trained networks achieve a purity-completeness level of ∼ 91% in detecting such events. The methodology presented can be extended to other data-intensive surveys carried out with the next-generation facilities.

Gravitationally lensed supernovae (SNe) are rare and valuable probes of astrophysics and cosmology. While only seven lensed SNe have currently been discovered, these numbers are predicted to increase by orders of magnitudes with future transient surveys such as the Legacy Survey of Space and Time (LSST). These proceedings describe the ongoing live search with the Zwicky Transient Facility (ZTF), including the discovery of SN ‘Zwicky’: a lensed SN found in a remarkably low-mass lens galaxy. Finally, we look ahead at predictions for detecting lensed SNe with LSST.

We present our systematic infrared and (sub)millimeter spectroscopic observations of gas/dust-rich merging ultraluminous infrared galaxies (ULIRGs) to scrutinize deeply buried AGNs (mass-accreting supermassive black holes [SMBHs]). We have found signatures of optically elusive, but intrinsically luminous buried AGNs in a large fraction of nearby (z < 0.3) ULIRGs, suggesting that SMBH mass growth is ongoing in the ULIRG population. Using ALMA, we have detected compact (<100 pc), very luminous (>104Lʘ), AGN-origin, 183 GHz (1.6 mm) H2O megamaser emission in one merging ULIRG, demonstrating that the megamaser emission can be a very powerful tool to dynamically estimate SMBH masses, with the smallest modeling uncertainty of kpc-wide stellar and gas mass distribution, at dusty ULIRGs’ nuclei, because of minimum extinction effects at millimeter. We present our current results and future prospect for the study of the SMBH mass growth in gas/dust-rich galaxy mergers, using (sub)millimeter AGN-origin H2O megamaser emission lines.

The gravitational lens SDSS J1004+4112 was the first discovered system where a background quasar is lensed by a galaxy cluster instead of a single galaxy. We use the 14.5-year r-band light curves together with the recently measured time delay of the fourth brightest quasar image (Munõz et al. (2022)) and the mass model from Forés-Toribio et al. (2022) to study the microlensing effect in this system. We constrain the quasar accretion disk size to light-days at 2407Å in the restframe which is compatible with most previous estimates. We also infer the fraction of mass in stars at the positions of the quasar images: $${\alpha _A} = 0.058_{ - 0.032}^{ + 0.024},{\alpha _B} = 0.048_{ - 0.014}^{ + 0.032},{\alpha _C} = 0.018_{ - 0.018}^{ + 0.015}$$ and $${\alpha _D} = 0.008_{ - 0.008}^{ + 0.033}$$. The stellar fraction estimates are reasonable for intracluster medium although the stellar fractions at images A and B are slightly larger, suggesting the presence of a near undetected galaxy.

In this contribution we describe the jet transport techniques that we used in Pérez-Hernández and Benet (2022) for the estimation of the Yarkovsky transversal acceleration for (99942) Apophis, which included optical and radar astrometry observations obtained during 2021 Apophis’ fly-by. Our numerical approach exploits automatic differentiation techniques which improve the orbital determination problem. We obtain a non-zero Yarkovsky parameter A2 = (−2.899±0.025) × 10−14 au d−2 which is consistent with other recent determinations of this parameter. Our results allow to constrain the collision probabilities for the close approaches in 2029, 2036 and 2068.

In this Review, I discuss recent developments on the long-term dynamical evolution of exoplanet systems, focusing on how distinctive dynamical processes may have shaped the orbital architectures of observed populations. I include three applications that highlight part of my own work. First, I examine the high-eccentricity tidal migration of hot Jupiters from a phase of dynamical instability and subsequent secular interactions in two-planet systems. Second, secular chaos as the origin of ultra-short-period planets with extreme period ratios. Third, secular resonance sweeping driven by a dispersing protoplanetary disk as the origin hot Neptunes residing in polar orbits. Finally, I discuss how upcoming observations will allow further constraining the prevalence of these dynamical processes.

In the last five years, the number of periodic variable stars has increased by two million. We used the ZTF DR2 data to find and build a catalog that includes 780,000 periodic variable stars. These periodic variable stars were classified into 11 types, which greatly complemented the variable stars in Galactic disk. Based on the latest ZTF DR16 data, we found 2 million variable candidates. We trained a machine learner to classify variable stars, and the learner had a prediction accuracy of 94%. Using millions of variable stars, we carried out studies to optimize the period–luminosity relations and the Galactic structure and the extinction law. With the future China Space Station Telescope, millions of variable stars in the Local Group will be discovered. They help to study the structure of our Local Group and also to cross-check the distance ladders based on different variable stars.

The lightcurves of strongly lensed AGNs get distorted due to gravitational microlensing, which differently magnifies the emission regions of AGNs depending on their size. This effect has been used to measure the size of the AGN accretion disc, but high photometric accuracy lightcurves reveal coherent variations on short time-scales that are not expected by standard accretion disc models. I show that this signal can be produced by emission from the Broad Line Region (BLR) but also by extended (diffuse) continuum emission. I explain how these features can be used to measure the size of the BLR but also reveal additional sources of emission. The multi-colour lightcurves of lensed AGNs, such as those to be obtained with the Vera Rubin Observatory, may become a powerful new tool to reveal the sub-parsec structure of AGNs, and shed light on elusive AGN emitting regions such as the one producing diffuse continuum emission.

We are investigating the extended outflow from G25.82–W1, which is one of the members of the high-mass protocluster G25.82–0.17. The aim is to study the star-forming environment of G25.82–W1. To identify the outflow, we obtained CO 2-1 data using the Atacama Large Millimeter/submillimeter Array.

We have identified several spatial and spectral outflows, including: 1) an extended N1–S1 CO outflow, driven by a high-mass young stellar object (HM-YSO) named G25.82–W1; 2) an elongated SE–NW outflow powered by G25.82–W2; 3) a compact and curved N2–S2 CO outflow originating from G25.82–E; and 4) a pair of knotty lobes centered on G25.82–W.

Furthermore, the innermost region of the N1–S1 CO outflow, traced by the 22 GHz H2O maser, reveals a complex spatial and velocity structure within a 2” from its launching point.

To accurately calculate the properties of the N1–S1 CO outflow, we have utilized an accurate distance measurement of d=4.5 kpc, derived from the annual parallax of the H2O masers. The outflow rate and force are comparable to those observed in outflows from other HM-YSOs. The physical properties of the N1–S1 CO outflow follow a trend connecting the low and high-mass regimes, supporting the idea that the star-forming mode in G25.82–W1 is likely a scaled-up version of low-mass star formation.

We present a progress report of our project aiming to increase the number of known Cepheids in double-lined binary (SB2) systems from six to 100 or more. This will allow us, among other goals, to accurately measure masses for a large sample of Cepheids. Currently, only six accurate Cepheid masses are available, which hinders our understanding of their physical properties and renders the Cepheid mass–luminosity relation poorly constrained. At the same time, Cepheids are widely used for essential measurements (e.g., extragalactic distances, the Hubble constant). To examine Cepheid period–luminosity relations, we selected as binary candidates Cepheids that are too bright for their periods. To date, we have confirmed 56 SB2 systems, including the detection of significant orbital motions of the components for 32. We identified systems with orbital periods up to five times shorter than the shortest reported period to date, as well as systems with mass ratios significantly different from unity (suggesting past merger events). Both features are essential to understand how multiplicity affects the formation and destruction of Cepheid progenitors and what effect this has on global Cepheid properties. We also present eight new systems composed of two Cepheids (only one such system was known before). Among confirmed SB2 Cepheids, there are also several wide-orbit systems. In the future, these may facilitate independent accurate geometric distance measurements to the Large and Small Magellanic Clouds.