Recent observations have provided evidence that the solar photospheric magnetic fields could have rapid and permanent changes in both longitudinal and transverse components associated with large (X- or M-class) solar flares. However, few observations have been reported about small flares. In this paper we find the observational evidence of changing photospheric vector magnetic fields associated with a B4.2-class flare obtained with the Solar Magnetic Field Telescope (SMFT) installed at Huairou Solar Observing Station (HSOS) of Nation Astronomical Observatories of Chinese Academy of Sciences.

Recoil velocity is examined as a back reaction to the magnetic dipole and quadrupole radiations from a pulsar/magnetar born with rapid rotation. The model is extended from notable Harrison-Tademaru one by including arbitrary field-strength of the magnetic quadrupole moment. The process is slow one operating on a spindown timescale. Resultant velocity depends on not the magnitude, but rather the ratio of the two moments and their geometrical configuration. The model does not necessarily lead to high spatial velocity for a magnetar with a strong magnetic field. This fact is consistent with the recent observational upper bound. The maximum velocity predicted with this model is slightly smaller than that of observed fast-moving pulsars.

We derive the C/O ratio for the exoplanet host star 55 Cnc based on archive Keck/HIRES spectra. The C/O ratio varies widely depending on which oxygen abundance indicator – the 6300.3 Å [O I] line, the 6363.8 Å [O I] line, or the 7774 Å O I triplet – is used, and we find there is still a large uncertainty even based on individual abundance indicators. This case study demonstrates that caution and care are necessary when determining exoplanet host star C/O ratios, and when considering host star C/O ratios in inferring exoplanet compositions.

Based on BATC and SDSS photometric data, we adopt the spectral energy distribution (SED) fitting method to evaluate stellar metallicities in the Galaxy. We find that the mean metallicity shifts from metal-rich to metal-poor with the increase of distance from the Galactic Centre.

We present evidence of a new planetary system around the K giant η Cet (HIP 5364, HD 6805, HR 334), based on 124 high-precision optical and infrared radial velocity data, taken at Lick Observatory (Hamilton) and at VLT (CRIRES). The best dynamical fit to the data is consistent with two massive planets (m1sini≈2.6MJup, m2sini≈3.3MJup) and with periods of P1≈407 days, P2≈740 days. To test the η Cet system's stability we perform ~ 10,000 dynamical investigations with maximum time spans of 108 years. We find that in case of moderate eccentricities, the planets can be effectively trapped in an anti-aligned stable 2:1 mean motion resonance (MMR), very close to the separatrix. A larger non-resonant stable region exists in low-eccentricity parameter space, although less probable than the 2:1 MMR region.

We briefly summarize the method of simulating Sgr A* polarized sub-mm spectra from the accretion flow and fitting the observed spectrum. The dynamical flow model is based on three-dimensional general relativistic magneto hydrodynamic simulations. Fully self-consistent radiative transfer of polarized cyclo-synchrotron emission is performed. We compile a mean sub-mm spectrum of Sgr A* and fit it with the mean simulated spectra. We estimate the ranges of inclination angle θ=42°–75°, mass accretion rate Ṁ=(1.4-7.0)×10−8M⊙year−1, and electron temperature Te=(3–4)×1010K at 6M. We discuss multiple caveats in dynamical modeling, which must be resolved to make further progress.

We carried out a search for pulsars in nearby galaxies with the GBT and Arecibo radio telescopes at 820 and 327 MHz, correspondingly. Currently, the Magellanic Clouds are the only galaxies except for Milky Way known to harbor radio pulsars, with a total of 20 pulsars being discovered there to date. Discovery of pulsars in other galaxies can be used to trace the history of massive star formation and would allow to probe the intermediate intergalactic medium. We selected 22 galaxies of the Local Group at high galactic latitudes, |b| > 26 deg, with most of them being dwarf spheroidals with old star population. This makes them promising targets to search for giant pulses from recycled millisecond pulsars. Both single-pulse and periodicity searches were performed for trial dispersion measures up to 1000. No extragalactic pulsars are found in half of the selected targets processed so far. I will give the overview of our targetted searches, present potential candidates and discuss the obtained results.

In this paper, we study twisting motions of the penumbral filaments of active region NOAA 10930. At first, they made unwinding motions. After unwinding, the filaments are found to twist again and developed the opposite chirality in them. These observational results indicate that penumbral filaments are more inclined to be the twisted magnetic flux tubes in nature.

During an unusually massive filament eruption on 7 June 2011, SDO/AIA imaged for the first time significant EUV emission around a magnetic reconnection region in the solar corona. The reconnection occurred between magnetic fields of the laterally expanding CME and a neighbouring active region. A pre-existing quasi-separatrix layer was activated in the process. This scenario is supported by data-constrained numerical simulations of the eruption. Observations show that dense cool filament plasma was re-directed and heated in situ, producing coronal-temperature emission around the reconnection region. These results provide the first direct observational evidence, supported by MHD simulations and magnetic modelling, that a large-scale re-configuration of the coronal magnetic field takes place during solar eruptions via the process of magnetic reconnection.

Ammonia (NH3) was the first polyatomic molecule observed in the ISM. Its importance in interstellar molecules is only second to CO because its rovibrational spectroscopic signature can be used very effectively at deducing the conditions of the interstellar environment such as temperature and density, and because it is found in so many different interstellar objects in a wide temperature range. However, experimental determination of NH3 IR spectra is extremely difficult due to the large-amplutide inversion vibration, and the existing HITRAN2008 database for NH3 is limited in temperature, coverage, completeness, and accuracy. With rapid progress in theoretical chemistry and computational resources, now we are able to generate a highly reliable/accurate IR line list of NH3 (and its isotopologues) for astronomical studies. Exact quantum rovibrational computations on an empirically refined potential energy surface (with nonadiabatic corrections included) have achieved accuracies of 0.02-0.05 cm−1 (for line position) and better than 85-95% (for line intensity) for both NH3 and 15NH3 spectra. The unique feature of our work is that our predictions are essentially as accurate as reproducing existing measurements, suitable for synthetic simulation of various astrophysical environments or objects. The reliabilty and accuracy of our predictions for missing bands and higher energies computed on HSL-2 (Fig. 1) have been proved by the most recent high-resolution experiments and extended up to 7000 cm−1. See Huang et al. 2008, Huang et al. 2011, & Sung et al. 2012 for more details.

We study an EUV wave initiated in active region (AR) 11261 on 2011 August 4 by using the SDO/AIA and the Hinode/EIS. We found that: (1) the EUV wave interacted with AR loops between AR 11261 and AR 11263, and exited mass flows in these loops. (2) EIS observations of AR loops in AR 11263 revealed that at the time of the wave transit, the original red-shifted feature had an increase of about 3 km s−1, and the original blue-shifted feature slightly weakened. These findings could be explained in the framework of a fast-mode magnetosonic wave interpretation for EUV waves.

Radiation of supersoft X-ray sources (SSS) dominates both the supersof X-ray and the far-UV domain, and can be detected also within the optical/near-IR wavelengths. To determine fundamental parameters of SSSs, a multiwavelength approach in modeling their spectra is essential. By this way, the basic physical parameters of a SSS (the temperature, radius, luminosity and column density of the neutral hydrogen) can be determined unambiguously. Here I demonstrate this case for the symbiotic X-ray binary RXJ0059.1-7505 (LIN 358) in the Small Magellanic Cloud (SMC).

We use the full spectrum fitting ability of ULySS, with the Pegase.HR stellar population model to fit the observed spectra of 40 brightest cluster galaxies in order to determine whether a single or a composite stellar population provided the most probable representation of the star formation history (SFH). We find that some galaxies in the sample have more complex SFHs.

The Next Generation Transit Survey (NGTS) is a new ground-based survey for transiting exoplanets. Our primary goal is to find the first statistically-significant sample of Neptunes and super-Earths that are bright enough for radial velocity confirmation. By measuring precise masses and radii we will constrain the bulk composition and internal structure of planets that span the transition between the gas giants and terrestrial planets. Our brightest exoplanets will also be suitable for atmospheric characterisation with large facilities such as the VLT, JWST and the E-ELT. NGTS construction began in June 2013, and the survey is due to commence in 2014.

We describe an on-going 194-671 μm spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs) with Herschel SPIRE Fourier Transform Spectrometer (FTS). The survey targets primarily the CO spectral line energy distribution (SLED), from J = 4-3 up to J = 13-12, to probe dense and warm molecular gas that should play an intimate role in star formation and/or active galactic nuclear activities in these galaxies. The program is about 75% finished. At S/N > 5, besides the CO lines, we also detected [N ii] 205 μm and [C i] 370 μm (3P2 − 3P1) lines in every target observed. In about half of the observed targets, we also detected [C i] 609 μm (3P1 – 3P0).

We present the results from nearly three years of monitoring of the variations in dispersion measure (DM) along the line-of-sight to 11 millisecond pulsars using the Giant Metrewave Radio Telescope (GMRT). These results demonstrate accuracies of single epoch DM estimates of the order of 5 × 10−4 cm−3 pc. A preliminary comparison with the Parkes Pulsar Timing Array (PPTA) data shows that the measured DM fluctuations are comparable. We show effects of DM variations due to the solar wind and solar corona and compare with the existing models.

By using the data of Solar Dynamics Observatory (SDO), we present a case study of the contraction of the overlying coronal loop and the rotation motion of a sigmoid filament on 2012 May 22. At the beginning of the filament eruption, the overlying coronal loop experienced a significant contraction. In the following, the filament started to rotate counterclockwise. We also carried the simulation to investigate the process of the filament eruption.

We test observational consequences of primordial Kerr superspinars indicated by string theories. We demonstrate that Kerr superspinars can serve as ultra-high energy accelerators and explore specific optical phenomena related to accretion discs orbiting them.