The center of our Galaxy hosts a Super-Massive Black Hole (SMBH) of about 4 × 106 M⊙. Since it has been argued that the SMBH might accelerate particles up to very high energies, its current and past activity could contribute to the population of Galactic cosmic-rays (CRs). Additionally, the condition in the Galactic Center (GC) are often compared with the one of a starburst system. The high supernovae (SN) rate associated with the strong massive star formation in the region must create a sustained CR injection in the GC via the shocks produced at the time of their explosion.

The presence of an excess of very high energy (VHE) cosmic rays in the inner 100 pc of the Galaxy in close correlation with the massive gas complex known as the central molecular zone (CMZ) has been revealed in 2006 by the H.E.S.S. collaboration. Recently, by analysing 10 years of H.E.S.S. data, the H.E.S.S. collaboration confirmed the presence of this extended VHE diffuse emission and deduced a CR density peaked toward the GC. The origin of the CR over-abundance in the GC still remains mysterious: Is it due to a single accelerator at the center or to multiple accelerators filling the region?

In order to investigate the presence of these multiple CR accelerators, and in particular the impact of their spatial distribution on the VHE emission morphology, we build a 3D model of CR injection and diffusive propagation with a realistic 3D gas distribution. We discuss the CR injection in the region by a spectral and morphological comparison with H.E.S.S. data.

We show that a peaked γ-ray profile towards the GC center is obtained using a realistic SN spatial distribution taking into account the central massive star clusters. The contribution of theses sources cannot be neglected in particular at high longitudes. In order to fit the very central excess observed with H.E.S.S., another central VHE component is probably necessary.

Comparison of galaxy flows with those predicted from the local galaxy distribution ended as an active field after two analyses came to vastly different conclusions 25 years ago, but that was due to faulty data. All the old results are therefore suspect. With new data collected in the last several years, the problem deserves another look. The goal is to explain the 640 km/s dipole anisotropy of the CMBR. For this we analyze the gravity field inferred from the enormous data set derived from the 2MASS collection of galaxies (Huchra et al. 2005), and compare it to the velocity field derived from the well calibrated SFI++ Tully-Fisher catalog (Springob et al. 2007). Using the “Inverse Method” to minimize Malmquist biases, within 10,000 km/s the gravity field is seen to predict the velocity field (Davis et al. 2011) to remarkable consistency. This is a beautiful demonstration of linear perturbation theory and is fully consistent with standard values of the cosmological variables.

Cold molecular and atomic gas plays a central role in our understanding of early galaxy formation and evolution. It represents the component of the interstellar medium (ISM) that stars form out of, and its mass, distribution, excitation, and dynamics provide crucial insight into the physical processes that support the ongoing star formation and stellar mass buildup. We here present results that demonstrate the capability of the Atacama Large (sub-)Millimeter Array (ALMA) to detect the cold ISM and dust in “normal” galaxies at redshifts z=5–6. We also show detailed studies of the ISM in massive, dust-obscured starburst galaxies out to z>6 with ALMA, the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the Plateau de Bure Interferometer (PdBI), and the Karl G. Jansky Very Large Array (VLA). These observations place some of the most direct constraints on the dust-obscured fraction of the star formation history of the universe at z>5 to date, showing that “typical” galaxies at these epochs have low dust content, but also that highly-enriched, dusty starbursts already exist within the first billion years after the Big Bang.

Time-series photometry and spectroscopy of transiting exoplanets allow us to study their atmospheres. Unfortunately, the required precision to extract atmospheric information surpasses the design specifications of most general purpose instrumentation. This results in instrumental systematics in the light curves that are typically larger than the target precision. Systematics must therefore be modelled, leaving the inference of light-curve parameters conditioned on the subjective choice of systematics models and model-selection criteria. Here, I briefly review the use of systematics models commonly used for transmission and emission spectroscopy, including model selection, marginalisation over models, and stochastic processes. These form a hierarchy of models with increasing degree of objectivity. I argue that marginalisation over many systematics models is a minimal requirement for robust inference. Stochastic models provide even more flexibility and objectivity, and therefore produce the most reliable results. However, no systematics models are perfect, and the best strategy is to compare multiple methods and repeat observations where possible.

We use semi-analytic models of galaxy formation L-Galaxies based on ΛCDM cosmology to study the HI gas component in galaxy outskirts. We adopt the radially-resolved version of the models by Fu et al. (2013), which includes both atomic and molecular gas component in interstellar medium. This model has been recently updated by Luo et al. (2016) to include cold gas stripping in the outer disk regions of the satellite galaxies by ram pressure. In our models, we can perfectly reproduce the HI size-mass relation, which is discovered by Broeils & Rhee (1997) and confirmed by many subsequent observations. In our model, the reason for such tight correlation between HI size and mass is atomic-molecular phase conversion in high gas surface density regions while HI ionization in low gas surface density region, which leads to very narrow distribution of HI mean surface density. The models also reproduce the universal exponential HI radial profiles in galaxy outskirts found by Bluedisk (Wang et al. 2013), which arises from cold gas accretion onto the galaxy disks in exponentially profiles.

The role of the large-scale structure is one of the most important theme in studying galaxy formation and evolution. However, it has been still mystery especially at z>2. On the basis of our ALMA 1.1 mm observations in a z ~ 3 protocluster field, it is suggested that submillimeter galaxies (SMGs) preferentially reside in the densest environment at z ~ 3. Furthermore we find a rich cluster of AGN-host SMGs at the core of the protocluster, combining with Chandra X-ray data. Our results indicate the vigorous star-formation and accelerated super massive black hole (SMBH) growth in the node of the cosmic web.

We present spectral data cubes of the [CI] 809 GHz, 12CO 115 GHz, 13CO 110 GHz and HI 1.4 GHz line emission from a ~1° region along the l = 328° (G328) sightline in the Galactic Plane. The [CI] data comes from the High Elevation Antarctic Terahertz telescope at Ridge A on the summit of the Antarctic plateau, where the extremely low levels of precipitable water vapour open atmospheric windows for THz observations. The CO data comes from the Southern Galactic Plane Survey being conducted with the Mopra telescope. Emission arises principally from gas in three spiral arm crossings along the sight line. The distribution of the emission in the CO and [CI] lines is found to be similar, with the [CI] slightly more extended, and both are enveloped in extensive HI. Spectral line ratios are similar across the entire extent of the Galaxy. However, towards the edges of the molecular clouds the [CI]/13CO and 12CO/13CO line ratios rise by ~ 50%, and the [CI]/Hi ratio falls by ~ 10%. We attribute this to sightlines passing predominantly through the surfaces of photodissociation regions (PDRs), where the carbon is found mainly as C or C+ rather than CO, while the gas is mostly molecular. This is the signature of dark molecular gas.

We present the first measurement of the anisotropy parameter β using 3D kinematic information outside of the solar neighborhood. Our sample consists of 13 Milky Way halo stars with measured proper motions and radial velocities in the line of sight of M31. Proper motions were measured using deep, multi-epoch HST imaging, and radial velocities were measured from Keck II/DEIMOS spectra. We measure β = −0.3−0.9+0.4, which is consistent with isotropy, and inconsistent with measurements in the solar neighborhood. We suggest that this may be the kinematic signature of a relatively early, massive accretion event, or perhaps several such events.

Using redshifts from the 2M++ redshift compilation, we reconstruct the density of galaxies within 200 h−1 Mpc, and compare the predicted peculiar velocities Tully-Fisher and SNe peculiar velocities. The comparison yields a best-fit value of β ≡ Ωm0.55/b* = 0.431 ± 0.021, suggesting Ωm0.55σ8,lin = 0.401 ± 0.024, in good agreement with other probes. The predicted peculiar velocity of the Local Group from sources within the 2M++ volume is 540 ± 40 km s−1, towards l = 268° ± 4°, b = 38° ± 6°, which is misaligned by only 10° with the Cosmic Microwave Background dipole. To account for sources outside the 2M++ volume, we fit simultaneously for β* and an external bulk flow in our analysis. The external bulk flow has a velocity of 159 ± 23 km s−1 towards l = 304° ± 11°, b6° ± 13°.

A new apodized Keplerian model is proposed for the analysis of precision radial velocity (RV) data to model both planetary and stellar activity (SA) induced RV signals. A symmetrical Gaussian apodization function with unknown width and center can distinguish planetary signals from SA signals on the basis of the width of the apodization function. The general model for m apodized Keplerian signals also includes a linear regression term between RV and the stellar activity diagnostic In (R'hk), as well as an extra Gaussian noise term with unknown standard deviation. The model parameters are explored using a Bayesian fusion MCMC code. A differential version of the Generalized Lomb-Scargle periodogram provides an additional way of distinguishing SA signals and helps guide the choice of new periods. Sample results are reported for a recent international RV blind challenge which included multiple state of the art simulated data sets supported by a variety of stellar activity diagnostics.

It has been indicated that low-luminosity active galactic nuclei (LLAGNs) are accelerating high-energy cosmic-ray (CR) protons in their radiatively inefficient accretion flows (RIAFs). If this is the case, Sagittarius A* (Sgr A*) should also be generating CR protons, because Sgr A* is a LLAGN. Based on this scenario, we calculate a production rate of CR protons in Sgr A* and their diffusion in the central molecular zone (CMZ) around Sgr A*. The CR protons diffusing in the CMZ create gamma-rays through pp interaction. We show that the gamma-ray luminosity and spectrum are consistent with observations if Sgr A* was active in the past.

I review the implementation of the effects from varying chemical element abundance ratios in stellar population modelling. Recent highlights include the adoption of new flux calibrated libraries, the inclusion of a wide range of chemical elements, the calculation of error estimates on the model, and the consideration of element variation effects on full spectra. Some key results on the element ratios measured in early-type galaxies are discussed.

The Sun drives most events of space weather in the vicinity of the Earth. Because the activities of the Sun are complicated, a visualized chart with key objects of solar activities is needed for space weather forecast. This work investigates the key objects in research during the past forty years and surveys a variety of solar observational data. We design the solar synoptic chart (SSC) that covers the key objects of solar activities, i.e., active regions, coronal holes, filaments/prominences, flares and coronal mass ejections, and synthesizes images from different heights and temperatures of solar atmosphere. The SSC is used to analyze the condition of the Sun in March 2012 and October 2014 as examples. The result shows that the SSC is timely, comprehensive, concise and easy to understand. It has the potentiality for space weather forecast and can help in improving the public education.

We exploit stellar population models of absorption features in the ultraviolet to assess their power in determining the age of the stellar population in galaxies. We focus in particular on features that can differentiate between an old UV-bright population, contributing to the UV upturn, and a young population due to recent star formation. We use a system of 8 indices between 2200 - 3200Å, tracing several chemical elements including Mg and Fe. We apply these models to a large sample of z ~ 0.6 massive galaxies from the Sloan Digital Sky Survey (SDSS) - III / Baryon Oscillation Spectroscopic Survey (BOSS) to derive the ages of the UV-bright populations. We find a subset of indices to be non-degenerate between old and young UV ages allowing us to find evidence for old stars contributing to the UV, rather than new star formation. We find up to 84% of our working sample (274,661 galaxies) to contain a contribution from old UV-bright stars. Those found to have higher contributing mass fractions being on average more massive and redder then those with lower mass fractions.

During the declining phase of the Solar cycle 24, a new peak appeared on January 7, 2014. The release of x-class flares, with the high energetic particles, were found to be more intense than that occurred during the main peak of the same cycle. Few X-class flares were released, lately, during the year 2014. We note that during the last 5 solar cycles, a new peak has appeared, releasing high energetic particles and X-class solar flares, which are called the secondary peak or the double peak of solar cycle. The aim of this descriptive study is to follow the morphological and magnetic changes of the active region before, during, and after the production of X-class flares according to data analysis. Furthermore, the causes of the release of such eruptive storms have been discussed for the period, year 2014, during the double peak of the solar cycle 24.

The origin of the IceCube astrophysical neutrinos is an outstanding question. Star-forming activities which can accelerate particles to very high energies have been suggested as possible origin of these neutrinos. I will present a scenario where a subset of the neutrino events originate from the Galactic center region and Fermi Bubbles, resulting from star-forming activities. Multi-messenger signal in high energy gamma rays and neutrinos can probe this scenario. I will also present an analysis of the statistical association of the star-forming sources in our Galaxy and outside, with astrophysical neutrinos, as well as expected neutrino signal from these sources by fitting gamma-ray data.

We use the UCAC4 and SDSS proper motions of about 7500 RR Lyrae type variables located within ~10 kpc from the Sun to study the dependence of their velocity ellipsoid on Galactocentric distance in the RG = 3–17 kpc interval. The radial velocity dispersion, σVR, decreases from ~190 km/s at RG = 3.5–5.5 kpc down to ~100 km/s at RG = 13–15 kpc, and the σVT/σVR ratio remains virtually constant (σVT/σVR ~0.54–0.64) in the Galactocentric distance interval from RG = 4.5 kpc to RG = 10.5 kpc increasing to ~0.9 both toward the Galactic center and beyond RG = 11 kpc.

We present an evolutionary model for the origin of Andromeda II, a dwarf spheroidal satellite of M31. The model is an extension of the scenario proposed by Łokas et al. (2014) involving a major merger between two gas-rich disky dwarf galaxies.

Our aim is to study the Star Formation Rate (SFR) by galaxy components such as bulges, bars and disks in a representative sample of nearby galaxies. A 2-dimensional (2D) photometric decomposition approach (GASP2D) is used to obtain these components. The availability of IFS data for the CALIFA galaxies makes possible to go one step further as we can apply the previous decompositions over 3D datacubes to disentangle the spatial distribution of the SFR over different components free from the limitations associated to narrow-band imaging.

Measuring the masses of rocky planets is quite difficult, as the relevant signal produced by such planets is often dwarfed by stellar activity by an order of magnitude or more. Developing a more robust way to isolate the stellar activity in these measurements is crucial to the search for Earth-like planets. We estimate the mass of Earth-size planet Kepler-78b using a Gaussian process estimator to describe the stellar activity in both photometric and radial velocity (RV) data, confirming previous results with a more robust technique that can be extended toward Earth analogues.