Recent progress on Baade–Wesselink (BW)-type techniques to determine the distances to classical Cepheids is reviewed. Particular emphasis is placed on the near-infrared surface-brightness (IRSB) version of the BW method. Its most recent calibration is described and shown to be capable of yielding individual Cepheid distances accurate to 6%, including systematic uncertainties. Cepheid distances from the IRSB method are compared to those determined from open cluster zero-age main-sequence fitting for Cepheids located in Galactic open clusters, yielding excellent agreement between the IRSB and cluster Cepheid distance scales. Results for the Cepheid period–luminosity (PL) relation in near-infrared and optical bands based on IRSB distances and the question of the universality of the Cepheid PL relation are discussed. Results from other implementations of the BW method are compared to the IRSB distance scale and possible reasons for discrepancies are identified.

In this paper, we estimated the black hole mass for some blazars with available variability time scales by assuming that the γ-ray emissions are from a distance of 200Rg from the center. The results show that the central black hole masses are in the range of log (M/M⊙) = 6.45 to 8.30.

This paper introduces a plan to detect turbulence profiles at Dome A with a Single Star Scidar (SSS), to enhance our understanding of the characteristics of the site. The development of a portable monitor for profiling vertical atmospheric optical turbulence and wind speed is presented. By analyzing the spatial auto and cross-correlation functions of very short exposure images of single star scintillation patterns, the SSS can provide the vertical profiles of turbulence intensity C2n(h) and wind speed V(h). A SSS prototype is already operational at Ali in Tibet which will be improved in order to become fully robotic and adapted to extreme weather conditions that prevail at Dome A in Antarctica.

Two flares occurred simultaneously in active region NOAA 9433 on 2001 April 25. The GOES X-ray fluxes show only one peak during the two flares. The negative magnetic polarities in the two flaring regions exhibited a clockwise rotation motion around the positive polarities, which can be seen from the evolution of the SOHO/MDI magnetograms. Through analyzing the potential fields extrapolated from the MDI magnetogram, we find that there is a channel strode by a group of magnetic field lines connecting the two flaring regions.

SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) was proposed in 2010 for a five-year M-class mission in the context of ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets located at several AUs (0.5-10 AU) from nearby stars (<25 pc) with masses ranging from a few Jupiter masses down to super-Earths (~2 Earth radii, ~10 M⊕), possibly habitable. In addition, circumstellar disks as faint as a few times the zodiacal light in the Solar System can be studied. SPICES is based on a 1.5-m off-axis telescope and can perform spectro-polarimetric measurements in the visible (450 - 900 nm) at a spectral resolution of about 40. This paper summarizes the top science program and the choices made to conceive the instrument. The performance is illustrated for a few emblematic cases.

Existence of liquid water on the planetary surface is thought to be an important condition for the origin and evolution of life. Planets with oceans (or lakes) are classified in two types: Earth-like ‘aqua planets’ and less water ‘land planets’. The latter shows stronger resistance than the former to the runaway greenhouse caused by the increase of stellar luminosity. We examined the possibility of evolution from an aqua planet to a land planet by water loss. We showed that an aqua planet with less than about 0.1 present Earth's ocean mass can evolve to a land planet without having experience of the runaway greenhouse, and maintains liquid water on its surface for about 2Gyrs longer than planets with larger amount of water. Our results mean that the initial amount of water is important for their evolution paths and habitability.

The evolution and dynamics of the molecular cores traced by 13CO J = 1 → 0 emission in the Taurus molecular cloud are studied. We performed a systematic examination of the distribution and dynamic state of cores in a large contiguous region, as well as the core ages, which lie between 106 and 107 years. The core velocity dispersion (CVD), which is the variance of the core velocity difference δ v, exhibits a power-law behavior as a function of the apparent separation L, i.e. CVD (km/s) ∝ L (pc)0.7, with similarities to Larson's law for the velocity dispersion of the gas.

The time delays between the multiple images of a strong gravitational-lens system, together with a model of the lens-mass distribution, provide a one-step determination of the time-delay distance, and thus a measure of cosmological parameters, particularly the Hubble constant, H0. I review the recent advances in measuring time-delay distances, and present the current status of cosmological constraints based on gravitational-lens time delays. In particular, I report the time-delay distance measurements of two gravitational lenses and their implication for cosmology from a recent study by Suyu et al.

The uncertainty of measurement of solar diameter is depending on the observational time scale. Full-disc images of SDO/HMI and the images from ground observations in Huairou Solar Observing Station have been analyzed to get the values of solar diameter. The satellite observations reach a very high precision, but the absolute image scale still need to be calibrated. The solar oblateness is a more challenging measurement than the diameter, since the signal amplitude is a few milli-arcseconds. It is a relative measurement, then not affected by the pixel scale calibration required by the diameter measurement. But the results are strongly dependent on the state of instrument such as focus plane deformation and on the calculation process.

We report 4-epoch VLBA observations of 3C 66A at 22GHz. The resulting images show a typical core-jet structure. We combine our results with some previous results to investigate the proper motions of the jet components. The kinematics of 3C 66A is quite complicated; mildly superluminal motions as well as apparent inward motions have been detected for some components. The inward motions may imply position change of the observed core.

Since November 2003, we have monitored AGB candidates in infrared wavelengths with the Kagoshima 1m telescope. We present the latest results based on the data until June 2011. For each of 400 monitored AGB stars, we estimate the periods, amplitudes, and mean apparent magnitudes in K band. Based on the two color diagram we choose 259 objects as Miras. We use the period–luminosity relation to obtain distances to them. As results we show the 3 dimensional distribution of 259 Mira variables.

Determination of trigonometric parallaxes is one of the very few direct methods available for measuring cosmic distances, and the only one capable of reaching beyond the Solar System. It is fundamental both to determine the intrinsic properties of astrophysical objects and as the first step on the cosmic distance ladder. Steady improvements of instruments and techniques have extended the applicability of the parallax method to ever greater distances. However, it is not correct to say that the method is independent of physical assumptions. This review covers ground-based optical techniques, from Bessel's time to the present, as well as space observations and radio interferometry. Some emphasis is put on the physical limitations of the method, in particular its sensitivity to source structure and photocentric variability on different timescales.

We study the properties of bars in a series of zoom cosmological simulations (Martig et al.2012, Kraljic et al.2012). We find that bars are almost absent from galaxies at z>1, and if they form they tend to be quickly destroyed by mergers and instabilities. On the contrary, at z<1 bars are long-lived, and the fraction of barred galaxies rises steadily. Bars are eventually found in ~ 80% of z=0 spiral galaxies. This redshift evolution is quantitatively consistent with existing data from the COSMOS survey (Sheth et al.2008), although the detectability of bars is presently limited to z<0.8 because of band-shifting and resolution effects. We predict later bar formation in lower-mass galaxies, also in agreement with existing data (e.g., Sheth et al.2012). We actually find that the characteristic epoch of bar formation is the epoch of massive thin disk formation, corresponding to the transition between an early violent phase at z > 1 and a later secular phase. Bar formation thus traces the emergence of the disk-dominated morphology of today's spirals.

Hydrodynamic simulations on the evolution of molecular clouds (MCs) at HII boundaries are used to show that radiation driven implosion (RDI) model can create almost all of the different morphological structures, such as a single bright-rimmed cloud (BRC), fragment structure and multiple elephant trunk (ET) structures.

Active galactic nuclei (AGN) are powered by energetic phenomena which cannot be attributed to stars. LINERs appears to be the low power end of the AGN sequence with the lowest Eddington ratios but hosting the most massive black holes (typically 109 M⊙). Whereas variability is common for high Eddington ratio emitting sources, in the low Eddington regime data are not so clear. Recent investigations at UV (Maoz et al. 2005) and X-ray frequencies (Younes et al. 2011, González-Martín et al. 2011) point out to the long term variable nature for some particular LINERs.

In this work we add more evidence about the X-ray variability in LINERs and investigate its nature. The data set comprises X-ray archival spectroscopy from observations taken from Chandra and XMM-Newton, selecting LINERs with several observations at different epochs. Up to now we analysed two LINER 1.9 objects, NGC 1052 and NGC 4278, and checked that variability is due to different mechanisms based on the results of spectral fittings.

The role of large-scale stellar feedback in the formation of molecular clouds has been investigated observationally by examining the relationship between Hi and 12CO(J = 1−0) in supershells. Detailed parsec-resolution case studies of two Milky Way supershells demonstrate an enhanced level of molecularisation over both objects, and hence provide the first quantitative observational evidence of increased molecular cloud production in volumes of space affected by supershell activity. Recent results on supergiant shells in the LMC suggest that while they do indeed help to organise the ISM into over-dense structures, their global contribution to molecular cloud formation is of the order of only ∼ 10%.

The on-going PALFA survey is searching the Galactic plane (|b| < 5°, 32° < l < 77° and 168° < l < 214°) for radio pulsars at 1.4 GHz using ALFA, the 7-beam receiver installed at the Arecibo Observatory. By the end of August 2012, the PALFA survey has discovered 100 pulsars, including 17 millisecond pulsars (P < 30 ms). Many of these discoveries are among the pulsars with the largest DM/P ratios, proving that the PALFA survey is capable of probing the Galactic plane for millisecond pulsars to a much greater depth than any previous survey. This is due to the survey's high sensitivity, relatively high observing frequency, and its high time and frequency resolution. Recently the rate of discoveries has increased, due to a new more sensitive spectrometer, two updated complementary search pipelines, the development of online collaborative tools, and access to new computing resources. Looking forward, focus has shifted to the application of artificial intelligence systems to identify pulsar-like candidates, and the development of an improved full-resolution pipeline incorporating more sophisticated radio interference rejection. The new pipeline will be used in a complete second analysis of data already taken, and will be applied to future survey observations. An overview of recent developments, and highlights of exciting discoveries will be presented.

I model changes in cyclotron line energy with luminosity, considering the effect of polar cap dimensions and changes in beam pattern as well as shock height. Cyclotron lines are calculated by a superposition of a large number of cyclotron lines formed in different heights of an accretion column. Cyclotron line energy has been observed to change with luminosity in a number of accreting X-ray pulsars. In X0115+63 and V0332+53, the fundamental cyclotron line energy has been observed to decrease with increasing luminosity. This phenomenon has been interpreted as a change in shock height with luminosity. However, the rate of the change seems to be very different, in which the line energy in V0332+53 seems to vary slowly with luminosity compared with that in X0115+63. I found that the changes in the cyclotron line energies with luminosity can be explained by changes in beam pattern and the size of a polar cap rather than a shock height.

The Herschel Reference Survey is a guaranteed time key project aimed at studying the physical properties of the interstellar medium (ISM) of 323 nearby galaxies, covered by multi-wavelength data. This volume limited, K-band selected sample is composed of galaxies spanning the whole range of morphological types and environments. We conduct a statistical study on the ISM properties of nearby galaxies based on the analysis of their SED. To achieve this goal, we fit the data with the models of Draine & Li (2007) to obtain the intensity of interstellar radiation field, the PAH abundance, the contribution of photodissociation regions, and the dust mass.

We study the gravitational fragmentation of a thick shell comparing the analytical theory to 3D hydrodynamic simulations and to observations of the Carina Flare supershell. We use both grid-based (AMR) and particle-based (SPH) codes to follow the idealised model of the fragmenting shell and found an excellent agreement between the two codes. Growth rates of fragments at different wavelength are well described by the pressure assisted gravitational instability (PAGI) - a new theory of the thick shell fragmentation. Using the APEX telescope we observe a part of the surface of the Carina Flare supershell (GSH287+04-17) in the 13CO(2–1) line. We apply a new clump-finding algorithm DENDROFIND to identify 50 clumps. We determine the clump mass function and we construct the minimum spanning tree connecting clumps positions to estimate the typical distance among clumps. We conclude that the observed masses and distances correspond well to the prediction of PAGI.