A major difficulty hampering the accuracy of UV/optical star formation rate tracers is the effect of interstellar dust, absorbing and scattering light produced by both young and old stellar populations (SPs). Although empirically calibrated corrections or energy balance SED fitting are often used for fast de-reddening of galaxy stellar emission, eventually only radiative transfer calculations can provide self-consistent predictions of galaxy model spectra, taking into account important factors such as galaxy inclination, different morphological components, non-local heating of the dust and scattered radiation. In addition, dust radiative transfer can be used to determine the fraction of monochromatic dust emission powered by either young or old SPs. This calculation needs to take into account the different response of the dust grains to the UV and optical radiation field, depending on the grain size and composition. We determined the dust heating fractions, on both global and local scales, for a high-resolution galaxy model by using our 3D ray-tracing dust radiative transfer code “DART-Ray”. We show the results obtained using this method and discuss the consequences for star formation rate indicators.

Current Cherenkov Telescopes for VHE gamma ray astrophysics are pointing instruments with a field of view up to a few tens of deg2. We propose to build an array of two non-steerable telescopes with a FoV of 5×60 deg2 oriented along the meridian. Roughly half of the sky drifts through this FoV in a year. We have performed a MC simulation to estimate the performance of this instrument, which we dub MACHETE. The sensitivity that MACHETE would achieve after 5 years of operation for every source in this half of the sky is comparable to the sensitivity that a current IACT achieves for a specific source after a 50 h devoted observation. The analysis energy threshold would be 150 GeV and the angular resolution 0.1 deg. For astronomical objects that transit over MACHETE for a specific night, it would achieve an integral sensitivity of 12% of Crab in a night. This makes MACHETE a powerful tool to trigger observations of variable sources at VHE or any other wavelengths.

Gufa, one of the traditional rituals, has been performed in Nepal since time immemorial by indigenous Newar people. In Gufa, a young girl who just had her first period is hidden in a sunless room for twelve consecutive days. This paper expounds the importance of ritual and its nexus with astronomy especially while interpreting how the daily motions of celestial objects have influenced the establishment and devolvement of a deep-rooted custom of Gufa.

An estimation of the mass of the main asteroid belt was made on the basis of the new version of EPM2014 ephemerides of the Institute of Applied Astronomy of Russian Academy of Sciences using about 800000 positional observations of planets and spacecraft. We obtained the individual estimations of masses of large asteroids from radar data, as well as estimates of the masses of asteroids by using known diameters and estimated average densities for the three taxonomic types (C, S, M), and used the known mass values of binary asteroids and asteroids to which spacecraft approached. A two-dimensional homogeneous annulus with dimensions corresponding observed width of the main asteroid belt (2.06 au and 3.27 au) was used instead of a previous massive one-dimensional ring for modeling total perturbations from small asteroids. The obtained value of the total mass of the main asteroid belt is (12.25 ± 0.19)10−10M⊙.

The majority of young massive stars are found in close binary systems. Recently, dedicated observing campaigns have provided strong constraints on the binary fraction as well as the distribution of the parameters that characterize the binary systems: the masses of both components, the orbital period and eccentricities. Most strikingly these findings imply that the majority of massive stars experience strong interaction (roche lobe overflow, a common envelope phase and or a merger) with a binary companion before their final explosion. I will discuss recent results from detailed binary star models and population synthesis models.

A large fraction of extremely metal-poor halo stars are strongly enriched in carbon (CEMP stars). The standard scenario for their origin is mass transfer in binary systems, but this assumes that they are binaries. If not, the C must have been implanted in their natal clouds from a distant production site(s) in the preceding - possibly first - generation of stars. The binary population of CEMP subgroups can shed light on these processes.

The activities and some research progress of IAU Commission 19 (C19) - Rotation of the Earth - in the past triennial term (2012-2015) is reported in this paper, including the scientific session and business meeting of C19, as well as a business meeting of the IAU/IAG Joint Working Group of “Theory of Earth Rotation” (JWG_ThER) during the XXIX IAU General Assembly in Hawaii, USA. Three reports of JWG_ThER progress, IERS and IAG, eleven reports of national projects and individual institutions, a short summary of the history and heritage of C19, and an Overview of the status and outlook of new Commission A2 are also presented.

ChemiX is a Bragg crystal spectrometer that will fly on the two Interhelioprobe spacecraft due for launch in 2025 and 2026. The spacecraft perihelion will be only 0.3 a.u. and the orbit inclination up to 30°, and so instruments on board will have a close view of solar active regions and flares and regions near each solar pole. The ChemiX X-ray spectrometer, built by a consortium of groups led by the Space Research Centre, Polish Academy of Sciences, will fly on each of the spacecraft, and observe X-ray spectra in the 1.5 - 9 Å range. Spectral lines in this range include resonance lines of helium-like and hydrogen-like ions of elements such as Fe, Ca, Ar, S, and Si, with less abundant elements such as K and Cl represented by weaker lines which the high sensitivity of ChemiX should be able to detect. The free–free and free–bound continua should also be detected since instrumental background will be eliminated. Three of the seven channels of ChemiX will be in a “dopplerometer” arrangement by which spatial and spectral shifts present in flare impulsive stages can be disentangled.

Abundant observations in recent years show that the flares are more complex than the 2D standard flare model presents. This proposes a challenge to the 2D flare model and 3D flare model has been developed. We report the complex evolution of flare ribbons and a flux rope in a C8.9 flare event. The two ribbons slipped in opposite directions along the neutral line and the eastern ribbon seemed a hook-like structure. The flare loops were crossed each other, composing a “bi-fan” system. The slipping magnetic reconnection is involved in the flare and leads to slipping motion of flare ribbons and complex evolution of flare loops. Overlying the flare loops, a large-scale flux rope was erupted and meanwhile the eastern end of the flux rope changed with time and slipped along the hook-like ribbon. The fine structures of the flux rope delineated a “triangle-flag” surface, which may imply one-half of the coronal quasi-separatrix layers that surrounds a flux rope. We suggest that the heating process of slipping magnetic reconnection during the flare caused the apparent motion of the flux rope ends.

The discovery of binary pulsar PSR 1913+16 by Hulse & Taylor in 1974 established the existence of gravitational waves, for which the 1983 Nobel Prize was awarded. However, the measurement of astrophysical parameters from gravitational waves will open an entirely new spectrum for discovery and understanding of the Universe, not simply a new window in the electromagnetic spectrum like gamma ray telescopes in the 1970s. Two types of ground-based detectors, Advanced LIGO/Virgo and Pulsar Timing Arrays, are expected to directly detect gravitational waves in their respective frequency bands before the end of the decade. However, many of the most exciting sources are in the band from 0.1–100 mHz, accessible only from space due to seismic and gravity gradient noise on Earth. The European Space Agency (ESA) has chosen the 'Gravitational Universe' as the science theme for its L3 Cosmic Visions opportunity, planned for launch in 2034. NASA is planning to participate as a junior partner. Here we summarize progress toward realizing a gravitational wave observatory in space.

We report our systematic survey observations of protostellar sources with the SubMillimeter Array (SMA) and Atacama Large Millimeter/submillimeter Array (ALMA). The purpose of our survey is to investigate formation mechanism of protoplanetary disks, precursors of planetary systems, out of ~1000 AU-scale protostellar envelopes surrounding the protostars. We found that in the early protostars (B335, NGC1333 IRAS 4B), the envelopes do not show significant rotating motions but infalling motions toward the central protostars. In more evolved protostars (L1527 IRS, L1448-mm, L1551 IRS 5), the envelopes are infalling and rotating with the conserved specific angular momenta (that is, v rot ∝ r −1). In most evolved sources (L1551 NE, TMC-1A, L1489 IRS) large-scale (≳100 AU) disks in Keplerian rotation or protoplanetary disks are evident. These results demonstrate a systematic evolutionary trend of envelope gas motions toward the disk formation.

Deflection missions to near-Earth asteroids will encounter non-negligible uncertainties in the physical and orbital parameters of the target object. In order to reliably assess future impact threat mitigation operations such uncertainties have to be quantified and incorporated into the mission design. The implementation of deflection demonstration missions offers the great opportunity to test our current understanding of deflection relevant uncertainties and their consequences, e.g., regarding kinetic impacts on asteroid surfaces. In this contribution, we discuss the role of uncertainties in the NEOTωIST asteroid deflection demonstration concept, a low-cost kinetic impactor design elaborated in the framework of the NEOShield project. The aim of NEOTωIST is to change the spin state of a known and well characterized near-Earth object, in this case the asteroid (25143) Itokawa. Fast events such as the production of the impact crater and ejecta are studied via cube-sat chasers and a flyby vehicle. Long term changes, for instance, in the asteroid's spin and orbit, can be assessed using ground based observations. We find that such a mission can indeed provide valuable constraints on mitigation relevant parameters. Furthermore, the here proposed kinetic impact scenarios can be implemented within the next two decades without threatening Earth's safety.

Galaxy nuclei are a unique laboratory to study gas flows. Their high-resolution imaging in galactic nuclei are instrumental in the study of the fueling and feedback of star formation and nuclear activity in nearby galaxies. Several fueling mechanisms can now be confronted in detail with observations done with state-of-the-art interferometers. Furthermore, the study of gas flows in galactic nuclei can probe the feedback of activity on the interstellar medium of galaxies. Feedback action from star formation and AGN activity is invoked to prevent galaxies from becoming overly massive, but also to explain scaling laws like black hole (BH)-bulge mass correlations and the bimodal color distribution of galaxies. This close relationship between galaxies and their central supermassive BH can be described as co-evolution. There is mounting observational evidence for the existence of gas outflows in different populations of starbursts and active galaxies, a manifestation of the feedback of activity. We summarize the main results recently obtained from the observation of galactic inflows and outflows in a variety of active galaxies with current millimeter interferometers such as ALMA or the IRAM array.

How large, 100-AU scale, rotationally supported disks form around protostars remains unsettled, both observationally and theoretically. In this contribution, we discuss the theoretical difficulties with disk formation in the presence of a dynamically significant magnetic field and their possible resolutions. These difficulties are caused by the concentration of magnetic field lines close to the forming star by protostellar collapse, and the strong magnetic braking associated with the concentrated field. Possible resolutions include magnetic field-rotation axis misalignment, non-ideal MHD effects, and turbulence. The field-rotation misalignment has been shown to promote disk formation, especially when the field is relatively weak and the misalignment angle is relatively large. Non-ideal MHD effects can enable the formation of small disks at early times. How such disks grow at later times remains to be fully quantified. Turbulence has been found to enable disk formation in a number of simulations, but the exact reason for its beneficial effect is debated.

A population of young, massive stellar cluster complexes with near-infrared (NIR) colors indicating high extinction (i.e. Av ~ 7m) was identified on HAWK-I/VLT images of several nearby, grand-design spiral galaxies. Models suggest that they are very young cluster complexes still embedded in a dust/gas envelope which will be expelled after 5-7 Myr. This type of very young, embedded clusters are not seen in optical studies using HST data.

A detailed comparison of HST and HAWK-I images was done to better understand the discrepancy between the optical and NIR detection of stellar clusters in nearby galaxies. More than 70% of the NIR clusters are located close to dust lanes which would make an optical detection difficult. A comparison of the ALMA CO(1-0)-map of NGC 4321 and the young, massive clusters shows that 60% of them have CO emission within 2“ indicating a correlation between giant molecular clouds and formation of massive clusters.

As a giant compact filamentary cloud, Orion A has a similar morphology with those more distant filaments in infrared dark clouds as revealed in Herschel surveys. We compared their core mass functions and found a similar power law index of N(>m)∝ m −1.0 for the high-mass end, which may possibly indicates a common case for massive filamentary clouds. We also show that the measured mass function for a certain cloud would largely depend on its distance, thus call for caution in interpreting individual measurements of CMF.

We are analysing late-time (older than about 150 d past explosion) optical spectra of Type II-Plateau (IIP) supernovae (SNe), which are H-rich SNe that come from red supergiant (RSG) progenitors. The dataset includes nearly 100 spectra of about 40 objects, making this the largest sample of SN IIP nebular spectra ever investigated. Quantitative criteria from within the spectra themselves are employed to determine if an observation is truly nebular, and thus should be included in the study. We present the temporal evolution of the fluxes, shapes, and velocities of various emission lines (see, for example, Fig. 1). These measured values are also compared to photometric data in order to search for correlations that can allow us to gain insight into the diversity of RSG progenitors and learn more about the details of the explosion itself.

IC5146 is one of the filamentary clouds observed in Herschel Gould Belt Survey. Here we present our polarization observations toward IC5146 taken with AIMPOL, TRIPOL and Mimir. Our results reveal that the large scale structure of magnetic field is well perpendicular to the main filament, but is likely parallel to the sub-filaments, which are structure extended out from the main filaments. We have also conducted CO observations to reveal the gas kinematics along the filaments or magnetic field; this result suggests the gas is possibly confined by magnetic field in most of the region until reaching supercritical. Based on our results, we suggests that at least four types of filaments can be found in IC5146, behaving different physical properties and consistent with different formation mechanisms. Our conclusions reveal that filaments are a combination of a variety types of objects.

Tidal interactions are a key process to understand the evolution history of close-in exoplanets. But tidals still have a large uncertainty in their prediction for the damping timescales of stellar obliquity and semi-major axis. We have worked on a search for transiting giant planets around evolved stars, for which few close-in planets were discovered. It has been reported that evolved stars lack close-in planets, which is often attributed to the tidal evolution and/or engulfment of close-in planets by the hosts. Meanwhile, Kepler has detected a certain fraction of transiting planet candidates around evolved stars. Confirming the planetary nature for these candidates is especially important since the comparison between the occurrence rates of close-in planets around main sequence stars and evolved stars provides a unique opportunity to discuss the final stage of close-in planets. With the aim of confirming KOI planet candidates around evolved stars, we measured precision radial velocities (RVs) for evolved stars with transiting planet candidates using Subaru/HDS. We also developed a new code which simultaneously models and fits the observed RVs and phase-curve variations in the Kepler data (e.g., transits, stellar ellipsoidal variations, and planet emission/reflected light). As a result of applying the global fit to KOI giants/subgiants, we confirmed two giant planets around evolved stars (Kepler-91 and KOI-1894), as well as revealed that KOI-977 is more likely a false positive.

Exceptionally deep observations of the distant universe with the Hubble Space Telescope have consistently pushed the frontiers of human knowledge. How deep can we go? What are the faintest and most distant galaxies we can see with the Hubble Space Telescope now, before the launch of the James Webb Space Telescope? This is the challenge taken up by the Frontier Fields, a director's discretionary time campaign with HST and the Spitzer Space Telescope to see deeper into the universe than ever before. The Frontier Fields combines the power of HST with the natural gravitational telescopes of high-magnification clusters of galaxies to produce the deepest observations of clusters and their lensed galaxies ever obtained. I will review the original goals of the Frontier Fields program and its progress over the last several years. In addition to pushing forward the study of the most distant galaxies, the Frontier Fields have been transformative in the study of galaxy clusters and their lensing properties. Finally, I will discuss the prospects for studying galaxies at cosmic dawn with JWST, extremely large ground-based telescopes, and future space missions over the next decade and beyond.