In the Titan Haze Simulation (THS) experiment, Titan's atmospheric chemistry is simulated by plasma discharge in the stream of a supersonic expansion, i.e. at low Titan-like temperature (150 K). Here, we present complementary gas and solid phase analyses of four N2-CH4-based gas mixtures that demonstrate the unique capability of the THS to monitor the chemical growth evolution in order to better understand Titan's chemistry and the origin of aerosol formation.

Gamma Ray Bursts (GRBs) can be used as a powerful tool to study galactic environments at different epochs of the Universe's evolution, thanks to their bright afterglow emission ranging from X-rays to optical and radio wavebands. Important aspect of the environment is dust, which plays a central role in the astrophysical processes of interstellar medium and in the formation of stars. GRBs can be a unique probe of dust at cosmological distances, where its origin and properties are still poorly known. By using a sample of GRB afterglow spectra observed with the VLT/X-shooter spectrograph we studied the rest-frame extinction in GRB lines-of-sight by modelling the broadband near-infrared to X-ray afterglow spectral energy distributions. We present our results on the rest-frame extinction of our sample, and illustrate that the spectroscopic data, thanks to a combination of excellent resolution and coverage of the blue part of the spectral energy distributions, are more successful than photometric measurements in constraining the extinction curves and therefore the dust properties in GRB hosts.

We describe a method to identify GRB host galaxies by means of their chemical abundances. We apply this method to three GRB hosts by comparing detailed chemical evolution models, including dust, of galaxies of different morphological type to observed abundance ratios. We conclude that none of them is likely to be a dwarf irregular galaxy, as it is believed for the majority of GRB hosts, but rather two of them (GRB081008 and GRB120327A) are likely to be spirals and the third is likely to be an elliptical (GRB120815). In addition, we have derived their chemical ages: in particular, the elliptical host is only 15 Myr old, while the other two hosts are 50 Myr (GRB120327A) and 320 Myr (GRB130815).

Single-dish observations in CS(J=7-6) using the Atacama Submillimeter Telescope Experiment (ASTE) reveal emission extending out to thousands of AU from low-mass protostars, much larger than is expected based on simple models for their envelopes. Hypotheses for this emission invoke gas dispersed from the envelope surfaces facing the bipolar outflow cavities. Here, we combine interferometric data from the Submillimeter Array (SMA) with the previous single-dish data from ASTE for the low-mass protostar L483 to study the spatial-kinematic structure of its CS(J=7-6) emission on projected scales ≳600 AU. In addition to providing more detailed information for the extended component, our combined maps reveal a compact central component in CS(J=7-6) having a steeper velocity gradient. Both the compact and extended components exhibit a velocity gradient in the opposite sense to that of a bipolar molecular outflow traced in CO(J=2-1). Finding that previous models make a number of wrong predictions for the observed features, we propose that both CS(J=7-6) components are produced by rotating and infalling gas along the envelope surfaces exposed by the bipolar outflow and therefore subjected to stellar irradiation and outflow compression.

We report a non-detection of CO(J=1-0) emission from one of the brightest Hii regions in the extended UV (XUV) disks of M 83 with on-source integration time of 11 hours.

Giant radio galaxies create the well distinguishable class of sources. These sources are characterized with edge-brightened radio lobes with highly collimated radio jets and large linear sizes which make them the largest individual structures in the Universe. They are also known to be hosted by elliptical/disturbed host galaxies and avoid clusters and high galaxy density regions. Because of GRG, large linear sizes lobes extend well beyond the interstellar media and host galaxy halo the evolution of the radio lobes may depend on interaction with this environment. Using our method to extract filamentary structure of the galaxies in our local universe we study whether radio lobe properties in some giant radio galaxies are determined on an interaction of this filament ambient.

Colliding plasmas are ubiquitous in astrophysical environments and allow conversion of kinetic energy into heat and, most importantly, the acceleration of particles to extremely high energies to form the cosmic ray spectrum. In collisionless astrophysical plasmas, kinetic plasma processes govern the interaction and particle acceleration processes, including shock formation, self-generation of magnetic fields by kinetic plasma instabilities, and magnetic field compression and reconnection. How each of these contribute to the observed spectra of cosmic rays is not fully understood, in particular both shock acceleration processes and magnetic reconnection have been proposed. We will review recent results of laboratory astrophysics experiments conducted at high-power, inertial-fusion-class laser facilities, which have uncovered significant results relevant to these processes. Recent experiments have now observed the long-sought Weibel instability between two interpenetrating high temperature plasma plumes, which has been proposed to generate the magnetic field necessary for shock formation in unmagnetized regimes. Secondly, magnetic reconnection has been studied in systems of colliding plasmas using either self-generated magnetic fields or externally applied magnetic fields, and show extremely fast reconnection rates, indicating fast destruction of magnetic energy and further possibilities to accelerate particles. Finally, we highlight kinetic plasma simulations, which have proven to be essential tools in the design and interpretation of these experiments.

The LAMOST Complete Spectroscopic Survey of Pointing Area (LCSSPA) at Southern Galactic Cap (SGC), is one of the LAMOST Key Project, designed to complete the spectroscopic observations of all Galactic and extra-galactic sources in two selected fields of 20 degrees2 at SGC, with the limiting magnitude of r = 18.1 mag. The main purposes of the project are focused on the completeness of the LAMOST ExtraGAlactic Surveys (LEGAS), testing the selection methods of galaxies and stars, and obtaining the basic performance parameters of the LAMOST telescope. Meanwhile the scientific studies include galaxies, clusters of galaxies, variable sources (quasars and variable stars), infrared excess stars and luminous infrared galaxies. The project has considerable scientific value since it is the most complete spectral data in LEGAS up to now. The project completed its observation in the early of 2014, and obtained at least 5000 spectra of galaxies and 25000 spectra of stars.

The progenitors of stripped-envelope supernovae (SNe Ibc) remain to be conclsuively identified, but correlations between SN rates and host-galaxy properties can constrain progenitor models. Here, we present one result from a re-analysis of the rates from the Lick Observatory Supernova Search. Galaxies with stellar masses ≲1010 M⊙ are less efficient at producing SNe Ibc than more massive galaxies. Any progenitor scenario must seek to explain this new observation.

The Planck satellite has mapped the polarized microwave sky (from 30 GHz to 353 GHz) with unprecedented sensitivity and angular resolution. This wealth of data yields the first complete map of polarized thermal emission from dust in our own Galaxy, shedding new light on the formation of dense cold structures within which new stars and planetary systems are born, under the combined effects of gravity, turbulence and magnetic fields. We present a statistical analysis of this polarized emission from nearby molecular clouds, with an emphasis on the evolution of the maximum polarization fraction observed as a function of column density, and on the anti-correlation between the polarization fraction and the local dispersion of polarization angles. To interpret this data, numerical simulations of anisotropic MHD turbulence underline the essential role played by the topology of the interstellar magnetic field, in particular its large-scale component. As an extension to this work published in Planck Intermediate Results XX (A&A, 576, 105, 2015), the statistical properties of the random component of the interstellar magnetic field are explored using a toy model based on fractional Brownian motion (fBm) fields.

Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors will be set up. We plan to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies, such as 25Mg(p,γ)26Al, 19F(p,α)16O, 13C(α,n)16O and 12C(α,γ)16O.

The direct collapse model of supermassive black hole seed formation requires that the gas cools predominantly via atomic hydrogen. To this end we simulate the effect of an anisotropic radiation source on the collapse of a halo at high redshift. The radiation source is placed at a distance of 3 kpc (physical) from the collapsing object and is set to emit monochromatically in the center of the Lyman-Werner (LW) band. The LW radiation emitted from the high redshift source is followed self-consistently using ray tracing techniques. Due to self-shielding, a small amount of H2 is able to form at the very center of the collapsing halo even under very strong LW radiation. Furthermore, we find that a radiation source, emitting < 1054 (∼103 J21) photons per second is required to cause the collapse of a clump of M ∼ 105 M⊙. The resulting accretion rate onto the collapsing object is ∼ 0.25 M⊙ yr−1. Our results display significant differences, compared to the isotropic radiation field case, in terms of H2 fraction at an equivalent radius. These differences will significantly effect the dynamics of the collapse. With the inclusion of a strong anisotropic radiation source, the final mass of the collapsing object is found to be M ∼ 105 M⊙. This is consistent with predictions for the formation of a supermassive star or quasi-star leading to a supermassive black hole.

In this work, we present a set of M-type star candidates selected from the LAMOST DR1. A discrimination method with the spectral index diagram is used to separate M giants and M dwarfs. Then, we have successfully assembled a set of M giants templates from M0 to M6, using the spectra identified from the LAMOST spectral database. After combining the M dwarf templates in Zhong et al. (2015a) and the new created M giant templates, we use the M-type spectral library to perform the template-fit method to classify and identify M-type stars in the LAMOST DR1. A catalog of M-type star candidates including 8639 M giants and 101690 M dwarfs/subdwarfs is provided. As an additional results, we also present other fundamental parameters like proper motion, photometry, radial velocity and spectroscopic distance.

The aim of this study is to determine abundance ratios and star formation histories (SFH) of dwarf ellipticals in the nearby Virgo cluster. We perform a stellar population analysis of 39 dEs and study them using index-index and scaling relations. We find an unusual behaviour where [Na/Fe] is under-abundant w.r.t. solar while [Ca/Fe] is over-abundant.

We study the assembly history of the stellar halo of Milky Way-like galaxies using the six high-resolution Aquarius dark matter simulations combined with the Munich-Groningen semi-analytic galaxy formation model. Our goal is to understand the stellar population contents of the building blocks of the Milky Way halo, including their star formation histories and chemical evolution, as well as their internal dynamical properties. We are also interested in how they relate or are different from the surviving satellite population. Finally, we will use our models to compare to observations of halo stars in an attempt to reconstruct the assembly history of the Milky Way's stellar halo itself.

Quasars are tracers of the cosmological evolution of the Black Hole mass – host galaxy relation, and indicate that the formation of BH anticipated that of the host galaxies. We find that selection effects and statistical biases dominate the interpretation of the observational results; and co-evolution (= constant BH/galaxy mass ratio) is still compatible with observations.

Gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. The Cherenkov Telescope Array (CTA) is an international initiative to build the next-generation ground-based gamma-ray observatory which will have a factor of 5-10 improvement in sensitivity in the 100 GeV - 10 TeV range and an extension to energies well below 100 GeV and above 100 TeV. CTA is planned to consist of two arrays (one in the North and another in the South Hemisphere) and will provide the deepest insight ever reached into the non-thermal high-energy Universe and its particle accelerators.

Submillimetre observations of externally irradiated low-mass protostellar envelopes show that the gas temperature in the envelopes is dominated by the external irradiation. Detailed studies of the protostar IRS7B in Corona Australis also show that the chemistry is strongly affected by the irradiation, depleting the abundances of complex organic molecules.

We describe new conversion laws, from CO molecular line data to inferred mass column, based on observations of the three main CO isotopologues in several surveys of the Galactic Plane. The new conversion laws replace the use of the single “X-factor” in widespread use, with a more physically-based relationship between the CO line’s optical depth, excitation, and column density. It has the effect of increasing the inferred mass column, over the single X-factor, by typically a factor of 2–3. This means that the molecular mass of the Milky Way may have been substantially underestimated in previous studies, and suggests that scaling laws like the Kennicutt-Schmidt relations may also need to be recalibrated. Because of its statistical basis on a large fraction of our Galaxy’s ISM, this new law is also recommended for use in studies of other Milky-Way-analogue spiral galaxies.

Superluminous supernovae (SLSNe) are an emerging class of SNe that exhibit luminosities exceeding those of SN Ia by an order of magnitude and have light curves with characteristic timescales of hundreds of days. Here we present observations of the host galaxies of 21 SLSNe observed with the Hubble Space Telescope, and show that their ultraviolet (UV) and near-infrared (nIR) luminosities and sizes and very different from those of the hosts of other core collapse events, with significant implications for their progenitors.