High atmospheric abundances of oxygen has been widely considered to be a reliable biosignature for life on exoplanets in the habitable zones of all types of stars. Recently it was proposed that the unique UV spectra of observed planet-hosting M dwarfs could lead to the buildup of molecular oxygen in the atmospheres of habitable but lifeless planets around these stars (Tian et al. 2014). However, the detectability of the accumulated O2 was not modeled. In this work we developed a new line by line radiative transfer model based on HITRAN database and used the model to simulate the reflectivity in the visible and near IR range. We show that abiotically produced and maintained O2 in the 0.2% level is observable at 13105 cm−1 (0.76 μm) with the spectra resolution of 70.

Concordia is a French-Italian permanent station located at Dome C, Antarctica. The station provides accommodation for up to 16 people over winter and more than 70 scientists and technicians during the austral summer. The scientific projects implemented at Concordia are strictly dependent on the characteristics of the site: a) the presence of a 3 300 m thick ice cap that allows access to the planet's climate archives and the reconstruction of glacial-interglacial cycles over more than 800 000 years; b) a particularly stable pure and dry atmosphere ideal for astronomy observations and for research on the chemical composition of the atmosphere; c) a distant location from coastal perturbations favourable to magnetic and seismological observatories to complement a poor world data network in the southern hemisphere; and d) a small totally isolated group of people confined to the station over a long winter, offering an opportunity for a range of medical and psychological studies useful to prepare long duration deep space missions.

We will address the main characteristics of this station and its interest for science.

Galactic gravitational microlensing is a powerful technique to detect extrasolar planets at large orbital distances from their stars, from giant down to Earth-mass planets. We report a statistical analysis (Cassan et al. 2012) that combines six years of microlensing observations gathered between 2002 to 2007 by the PLANET and OGLE collaborations. From these data, we estimate the frequency of cool extrasolar planets, with masses ranging from 5 Earths to 10 Jupiters and orbits between 0.5 to 10 Astronomical Units. We find that in average, one in six stars has a Jupiter-like gas giant as companion planet, that about half the stars are orbited by a Neptune-like giant, and two-thirds are associated to super-Earths. Our study also suggests that planets should be ubiquitous throughout the Galaxy. Current deployment of wide-field imagers and possible space-based observations onboard ESA spacecraft EUCLID will soon allow a large increase of the number of monitored microlensing events. These new observatories should provide in a near future a more detailed view on planet abundance as a function of mass.

We present high-sensitivity XMM/LOFAR observations that show for the first time that mode switching extends from radio to X-ray. In pulsar B0943+10, the known changes in radio profile and drift rate are confidently tied to simultaneous changes in X-ray emission.

In mode switching, seen in many pulsars, profile and subpulse-drift behavior change almost instantaneously. The mechanism for these drastic changes, or for the bi-stable emission behavior, is not understood; while even for the basic emission mechanism different families of theories (e.g. vacuum gap, or space-charge limited flow models) exist.

To discriminate between such models, we carried out a campaign of 42 hours of simultaneous LOFAR/XMM-Newton observations on PSR B0943+10. Through LOFAR's unparalleled low-frequency sensitivity, mode changes were pinpointed to 10-second accuracy. XMM X-ray photons were next separated by the two radio modes. We discovered large modal differences in the X-ray pulsations, flux, and spectral shapes: in the radio-bright mode, no X-ray pulsations are detected – but in the radio-quiet mode, B0943+10 is strongly pulsating in X-ray.

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 derive the optical afterglow luminosity distributions at different epoches for gamma-ray bursts (GRBs) from a sample of 146 GRBs that have a well-sampled optical afterglow lightcurve, then explore the luminosity function of GRB optical afterglows using the Monte Carlo simulation. We show that an intrinsic broken power-law luminosity function can well reproduced the observed magnitude distributions.

There are different methods for finding exoplanets such as radial spectral shifts, astrometrical measurements, transits, timing, etc. Gravitational microlensing (including pixel-lensing) is among the most promising techniques with the potential of detecting Earth-like planets at distances about a few astronomical units from their host stars. Here we emphasize the importance of polarization measurements which can help to resolve degeneracies in theoretical models. In particular, the polarization angle could give additional information about the relative position of the lens with respect to the source.

In astronomy it is important to promote observation and the quality of the sky is essential for a good observation impact. It is important that children have a nice memory of their observations in a non-polluted sky. Using students as agents of change it is possible to promote good practice for sky protection in society.

We investigated the variations of 74 microwave ZP structures observed by Chinese Solar Broadband Radio Spectrometer at 2.6–3.8 GHz in 9 solar flares, found that the ratio between the plasma density scale height LN and the magnetic field scale height LB in emission source displays a tendency of decrease during the flaring process, indicates that LB increases faster than the LN during solar flares. The detailed analysis of the step-wise decrease of LN/LB in three typical X-class flares reveals the magnetic field relaxation relative to the plasma density.

From the extreme position of disk motion, we infer the neutron star (NS) surface magnetic field strength (B0) of Z-source GX 17+2 and Cyg X-2. The inferred B0 of GX 17+2 and Cyg X-2 are ~(1–5)×108 G and ~(1–3)×108 G, respectively, which are not inferior to that of millisecond X-ray pulsars or atoll sources. It is likely that the NS magnetic axis of Z sources is parallel to the axis of rotation, which could result in the lack of pulsations in these sources.

Social media is a new trend in communicating and connecting to people. It is also a good choice to build awareness of astronomy as issues spread easily and quickly, creating hot topics. This paper will analyze the trend of astro talk in Indonesia and hope to inspire astronomers to use social media in raising awareness.

India is a country with a large number of languages which not only differ in scripts but are essentially part of different language families. “Marathi“ is one such Indian regional language spoken by nearly 70 million people and is the native language of the author. Like all major regional languages, there is a strong and vibrant media in Marathi with 45 odd newspapers and 6 television news channels.

The lifetime of contact binaries is an important parameter for studying the evolution of contact binaries. By reproducing the relative frequency of occurrence for contact binaries, we found that the lifetime of contact binaries decreases with increasing mass of the primaries. The lifetime of contact binaries is about 4%–10% of the main sequence lifetime of the primaries, and is about 0.006–0.65 Gyr. This suggests that the lifetime of contact binaries strongly depends on the mass of the primaries.

Dark Skies Rangers is an awareness program aimed at students of all ages to stimulate them to make an audit of light pollution in their school/district. The young light pollution fighters evaluate the level of light pollution, how much energy is being wasted, and produce a report to be delivered to the local authorities. They are also advised to promote a light pollution awareness campaign to the local community targeting not only the dark skies but also other implications such as effects in our health, to the flora and fauna, etc.

According to a popular scenario supported by numerical models, the mass assembly and growth of massive galaxies, in particular the Early-Type Galaxies (ETGs), is, below a redshift of 1, mainly due to the accretion of multiple gas–poor satellites. In order to get observational evidence of the role played by minor dry mergers, we are obtaining extremely deep optical images of a complete volume limited sample of nearby ETGs. These observations, done with the CFHT as part of the ATLAS3D, NGVS and MATLAS projects, reach a stunning 28.5 – 29 mag.arcsec−2 surface brightness limit in the g' band. They allow us to detect the relics of past collisions such as faint stellar tidal tails as well as the very extended stellar halos which keep the memory of the last episodes of galactic accretion. Images and preliminary results from this on-going survey are presented, in particular a possible correlation between the fine structure index (which parametrizes the amount of tidal perturbation) of the ETGs, their stellar mass, effective radius and gas content.

We investigate the properties of the galaxies hosting quasars in ~400 low redshift (z < 0.5) SDSS QSO that are in the “Stripe 82” sky area. For this region deep (r ~ 22.4 mag) u, b, v, r and i images are available and allow us to study both the host galaxies and the Mpc scale environments. This sample outnumbers previous studies of low-z QSOs. We present preliminary results of the properties of quasars activity and in particular we focus on the relationships among host galaxy luminosity, black hole mass, radio emission and the surrounding galaxy environments. We select from the SDSS - QSO Catalogue all the QSOs in the range of redshift 0.1<z<0.5 and in the Stripe82 region. This gives a total of 416 QSO. In this sample we are dominated by radio quiet quasars (about 5% are radio loud). In Fig. 1 we report the distribution of QSO in the plane redshift-MR (H0 = 70). The mean redshift of the sample is <z> = 0.39 and the average absolute magnitude is: <Mi> = −22.68. We implemented an automated procedure using AIDA (Uslenghi & Falomo 2011) to decompose the QSO images into nucleus and host galaxy luminosity. After masking of all contaminating sources in the field a 2D fitting is performed using PSF + galaxy model. In Fig. 1 we show an example of a QSO image in the sample and the distribution of the host galaxy absolute magnitude of the resolved objects.

In 2011, Bailes et al. reported on the discovery of a detached companion in a 131 minute orbit around PSR J1719–1438, a 173 Hz millisecond pulsar. The combination of the very low mass function and such a short orbital period is unique. The discoverers suggested that the progenitor system could be an ultracompact X-ray binary (UCXB), which is a binary with a sub-hour orbital period in which a (semi-)degenerate donor fills its Roche lobe and transfers mass to a neutron star. The standard gravitational-wave driven UCXB scenario, however, cannot produce a system like PSR J1719–1438 as it would take longer than the age of the Universe to reach an orbital period of 131 min. We investigate two modifications to the standard UCXB evolution that may resolve this discrepancy. The first involves significant heating and bloating of the donor by pulsar irradiation, and in the second modification the system loses orbital angular momentum via a fast stellar wind from the irradiated donor, additional to the losses via the usual gravitational wave radiation. In particular a donor wind is effective in accelerating orbital expansion, and even a mild wind could produce the 131 minute period within the age of the Universe. We note that UCXBs could be an important class of progenitors of solitary millisecond radio pulsars.

The dissipation of turbulence is a key process in the evolution of diffuse gas towards denser structures. The vast range of coupled scales and the variety of dissipative processes in interstellar turbulence make it a complex system to analyze. Observations now provide powerful statistics of the gas velocity field, density and magnetic field orientations, opening a rich field of investigation. On-going comparisons of the orientation of intense velocity-shears, magnetic field and tenuous filaments of matter in a turbulent high-latitude cloud are promising.

Enormous progress is being made in developing observational facilities. As a result, there are new opportunities to observe structures at sub-mas resolution. To explore gravitationally lensed systems, we simulate radio-lobe images distorted by microlensing. We show that the positions of ‘holes’ in lensed images may indicate the positions of microlens groups or overdensities.

We study how the solar magnetic field evolves from antisymmetric (dipolar) to symmetric (quadrupolar) state during the course of its 11-yr cycle. We show that based on equatorial symmetries of the induction equation, flux transport solar mean field dynamo models excite mostly the antisymmetric (dipolar) family whereas a decomposition of the solar magnetic field data reveals that both families should be excited to similar amplitude levels. We propose an alternative solar dynamo solution based on North-South asymmetry of the meridional circulation to better reconcile models and observations.