We have obtained high-resolution F110W (~ J) and F160W (~ H) band observations of ten submillimeter galaxies (SMGs) with the Hubble Space Telescope's NICMOS camera, in order to resolve their rest-frame optical morphologies, determine the existence of multiple-component, merger-like configurations, and estimate their stellar masses. The selected targets have redshifts in the range 2.2≤ z ≤ 2.81 confirmed with millimeter or mid-IR spectroscopy, guaranteeing that the two bands sample the galaxies' rest-frame optical light with the Balmer break falling between them.

The South Pole Telescope is a 10 meter telescope optimized for sensitive, high-resolution measurements of the cosmic microwave background (CMB) anisotropy and millimeter-wavelength sky. In November 2011, the SPT completed the 2500 deg2 SPT-SZ survey. The survey has led to several major cosmological results, derived from measurements of the fine angular scale primary and secondary CMB anisotropies, the discovery of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect and the resulting mass-limited cluster catalog, and the discovery of a population of distant, dusty star forming galaxies (DSFGs). In January 2012, the SPT was equipped with a new polarization sensitive camera, SPTpol, which will enable detection of the contribution to the CMB polarization power spectrum from lensing by large scale structure (the so-called “lensing B-modes”) and, on larger angular scales, a detection or improved upper limit on the primordial inflationary signal (“gravitational-wave B-modes”), thereby constraining the energy scale of Inflation. Development is underway for SPT-3G, the third-generation camera for SPT. The SPT-3G survey will cross the threshold from statistical detection of B-mode CMB lensing to imaging the fluctuations at high signal-to-noise; enabling the separation of lensing and inflationary B-modes and improving the constraint on the sum of the neutrino masses Σmν to a level relevant for exploring the neutrino mass hierarchy.

The prolonged period of solar minimum between cycles 23 and 24 has invoked a great deal of interest to understand the origin of the unusually low solar activity. Even though the origin of solar activity is believed to lie in the shear layer at the base of the convection zone, the analysis of helioseismic data seem to orientate us toward the near surface. In this context, we analyze the signature of the quasi-biennial periodicity seen in the oscillation frequencies which may provide additional constraints on the solar dynamo models.

Detecting the small velocity amplitudes (≤ 10 m/s) produced by habitable zone rocky planets around M Dwarfs requires radial velocity precisions of a few m s−1. However, an iodine absorption cell, commonly used as a high precision wavelength reference on non-stabilised spectrographs, is not efficient for very red and faint objects like M Dwarfs. Instead, arc lamps have to be used. With the exception of the ultra-stabilised HARPS spectrograph, achieving ~m s−1 calibration with arc lamps has not been possible because typical spectrographs experience drifts of several hundred m s−1 due to local atmospheric changes in pressure and temperature. We outline and present results from an innovative differential wavelength calibration method that enables ~m s−1 precision from non-stabilised, high-resolution spectrographs. This technique allows the detection of rocky planets with radial velocity amplitudes of a few m s−1.

Massive stars govern the evolution of galaxies by providing ionizing photons and energy as well as enriching heavy elements into interstellar medium; however, their formation is still poorly understood. Infrared dark clouds (IRDCs) are cold (< 25 K) and very dense (> 105 cm−3) interstellar clouds which are seen silhouette against the bright Galactic background in mid-IR. With very high column densities (∼ 1023–1025cm−2), IRDCs are believed to be the precursors to massive stars and star clusters (Simon et al. 2006).

We report a remarkable IRDC at (l, b) ∼ (53°.2, 0°.0) which shows a number of bright mid-IR stellar sources along the cloud that are likely young stellar objects (YSOs). There are also several H2 (at 2.122 μm) outflow features in the cloud revealed by UWISH2 (Ukirt Widefield Infrared Survey for H2, Froebrich et al. 2011), in particular where earlier evolutionary stage of YSOs are located. The IRDC was previously partly identified as three separate IRDCs in the MSXDC catalog (Simon et al. 2006), whereas we have found that a long, filamentary cloud extending ∼ 30 pc including these three IRDCs is very well coincident with a CO cloud at v ∼ 23.5 km/s (or at d ∼ 2 kpc) which is clearly distinct from the other velocity components. Therefore, in this study, we investigate the overall star formation activity in this IRDC (IRDC G53.2, hereafter).

We perform the PRF photometry of Spitzer MIPSGAL 24 μm data using MOPEX and build a catalog of YSOs by matching the detected 24 μm sources with published catalogs. The limiting magnitude in 24 μm is ∼ 7.8 mag, and YSO candidates which have counterparts in GLIMPSE I catalog are 354. The YSO candidates are classified using spectral index derived between 2 and 24 μm, following Greene et al. (1994). We also remove the field-star contamination using reference fields where there is no CO cloud; the fraction of each class after reference field analysis is 18, 22, 45, 10, and 5% for Class I, Flat, Class II, Class III, and sources which cannot be classified due to the lack of data. The spatial distribution that earlier classes (i.e., Class I and Flat) are concentrated where far-IR or millimeter emission is strong and larger fraction of Flat objects compared to other low-mass star forming regions (e.g., Evans et al. 2009 and Billot et al. 2010) may imply that the IRDC G53.2 is indeed an active star-forming region in rather early evolutionary stage. Further investigation of each YSO such as SED modeling will reveal detailed information on star formation activity in this intriguing IRDC.

Astrometric observations of neutron stars have been conducted with a variety of techniques and over a wide range of wavelengths, ranging from radio-pulse timing and Very Long Baseline Interferometry to optical and X-ray imaging. Here I review the techniques and scientific goals behind recent high-precision neutron-star astrometry. Such measurements can yield model-independent distances and velocities that can be exploited, for example, to locate neutron-star birth sites, establish reference-frame ties, model the Galactic electron-density distribution, and constrain the astrophysics of supernova explosions. Recently, the Fermi gamma-ray space telescope has identified several highly luminous recycled pulsars, and precise measurement of their distances is of paramount importance to understand their energetics and astrophysics. The ongoing science returns from precision astrometry will continue in the long term with improvements in technology such as focal-plane arrays and synergies with new telescopes such as Gaia and the Square Kilometer Array.

The neutron superfluid permeating the inner crust of mature neutron stars is expected to play a key role in various astrophysical phenomena like pulsar glitches. Despite the absence of viscous drag, the neutron superfluid can still be coupled to the solid crust due to non-dissipative entrainment effects. Entrainment challenges the interpretation of pulsar glitches and suggests that a revision of the interpretation of other observed neutron-star phenomena might be necessary.

We present results of Very Long Baseline Array (VLBA) polarimetric 22 GHz H2O maser observations of a number of low/intermediate mass evolved stars. We observed 3 Miras (Ap Lyn, IK Tau and IRC+60370), 1 semi-regular variable (RT Vir) and 1 pPN (OH231.8+4.2). Circular polarization is detected in the H2O maser region of OH231.8+4.2 and we infer a magnetic field of |B||| = ~45 mG. This implies an extrapolated magnetic field of ~2.5 G on the surface of the central star. The preliminary results on RT Vir and IRC+60370 also indicate the first detection of weak H2O maser linear polarization.

The Apodizing Phase Plate (APP) coronagraph has been used to image the exoplanet β Pictoris b and the protoplanet candidate around HD 100546, and is currently in use in surveys with NaCo at the VLT. Its success is due to its tolerance to tip-tilt pointing errors in current AO systems, which degrade the performance of nearly all other coronagraphs. Currently the sensitivity of the APP is limited by non-common path errors in the science camera systems and by its chromatic behaviour. We present the achromatized Vector APP coronagraph and address how we will measure and minimise non-common path errors with Focal Plane Wavefront Sensing algorithms.

The luminous accretion flares from tidally disrupted stars represent a powerful probe of the presence of supermassive black holes (SMBHs) in otherwise non-active galaxies, of accretion physics and BH spin, of jet formation, and relativistic effects. Further, the reprocessing of the continuum radiation of the flare into IR, optical and UV emission lines provides us with multiple new diagnostics of the properties of any gaseous material in the vicinity of the SMBH and in the host galaxy itself. While first events were discovered in the course of the ROSAT all-sky survey in X-rays, the last few years have seen the detection of several more flares, including in the UV, optical and radio band and via their emission-line “echoes”. A wealth of applications will become feasible in upcoming years, once flares are detected in large numbers in current and future sky surveys.

Using the Fast Imaging Solar Spectrograph of the 1.6 meter New Solar Telescope at Big Bear, we simultaneously took the spectral profiles of the Hα line and the Ca ii line at 854.2 nm from prominences beyond the solar limb and filaments on the disk. The spectral data were fitted by the slab model of radiative transfer with constant source function, either with zero background intensity profile (in prominences) or with carefully constructed background intensity profile (in filaments). These observations with different perspectives and different analyses produced consistent results: temperature inside prominences/filaments ranges from 4000 to 20000 K with a mean of about 9500 K. We expect that this kind of observation and analysis with higher spatial resolution and higher temporal resolution will allow us to study in detail the thermal structure and evolution of plasma in prominences.

Nearby galaxies come in two flavors: red quiescent galaxies (QGs) with old stellar populations, and blue young star-forming galaxies (SFGs). This color bimodality seems to be already in place at z = 2 − 3, presenting also strong correlations with size and morphology. Surprisingly, massive QGs at higher redshifts are ~5 times smaller than local, equal mass analogs. In contrast, most of the massive SFGs at these redshifts are still relatively large disks. The strong bimodality in both SFR and sizes indicates that some SFGs must experience strong structural transformations accompanied by a rapid truncation of the star-formation to match the observed properties of QGs. Using high-resolution HST/WFC3 F160W imaging from the CANDELS survey in GOODS-S and UDS, along with multi-wavelength ancillary data, we analyze stellar masses, SFRs and sizes of a sample of massive (M* > 1010M⊙) galaxies at z = 1.4 − 3.0 to identify a population of compact SFGs with similar structural properties as compact QGs at z~2. We also find that the number density of QGs increases rapidly since z = 3. Among these, the number of compact QGs builds up first, and only at z < 1.8 we do start finding a sizable number of extended QGs. This suggests that the bulk of these galaxies are assembled at late times by both continuous migration (quenching) of non-compact SFGs and size growth of cQGs. As a result of this growth, the population of cQGs disappears by z~1. Simultaneously, we identify a population of compact SFGs (cSFGs) whose number density decreases steadily with time since z = 3.0, being almost completely absent at z < 1.4. The number of cSFGs makes up less than 20% of all massive SFGs, but they present similar number densities as cQGs down to z~2, suggesting an evolutionary link between the two populations.

We study Rayleigh–Taylor instability (RTI) at the coronal–prominence boundary by means of 2.5D numerical simulations in a single-fluid MHD approach including a generalized Ohm's law. The initial configuration includes a homogeneous magnetic field forming an angle with the direction in which the plasma is perturbed. For each field inclination we compare two simulations, one for the pure MHD case, and one including the ambipolar diffusion in the Ohm's law, otherwise identical. We find that the configuration containing neutral atoms is always unstable. The growth rate of the small-scale modes in the non-linear regime is larger than in the purely MHD case.

A common approach to determining distances to stars without astrometric information is to compare stellar evolution models with parameters obtained from spectroscopic techniques. This method is routinely applied in the context of large-scale stellar surveys out to distances of several kpc. However, systematic errors may arise because of inaccurate spectroscopic parameters. We explore the effects of non-local thermodynamic equilibrium (NLTE) on the determination of surface gravities and metallicities for a large sample of metal-poor stars within approximately 10 kpc of the Sun. Using the improved Teff scale, we then show that stellar parameters estimated based on the widely used method of 1D LTE excitation-ionization balance of Fe results in distances which are systematically in error. For metal-poor giants, [Fe/H] ~ −2 dex, the distances can be overestimated by up to 70%. We compare the results with those from the Radial Velocity Experiment Survey catalogue (rave) for the stars in common, and find similar offsets.

Surface environment of habitable exoplanets will be important for astrobiologists on exoplanets in near future. Diverse surface environments on the Earth including continents, ocean, and meteorological condition (clouds and rains) serve as the backbone of biodiversity. One of the promising approaches to know the landscape of the terrestrial exoplanets is to use scattered light of the planet through direct imaging.

Since spin rotation and orbital revolution change illuminating area on planetary surface and cause time variation to disk-integrated brightness, light curves carry spatial information on the planetary surface. We propose an inversion technique of annual reflected light curves to sketch a two-dimensional albedo map of exoplanets, named the spin-orbit tomography (SOT). Applying the SOT to realistic simulations of the reflected light of an Earth-twin, we demonstrate how the SOT works. The mean cloud and continental distributions can be roughly obtained with single band photometry and difference of two-bands photometry, respectively. The SOT retrieves the planetary image without actually resolving the planet, which can be used to know the habitat of the exoplanets in near future.

We collected 27 outflows from the literature and found 8 new ones in the FCRAO CO maps of the Taurus molecular cloud. The total kinetic energy of the 35 outflows is found to be about 3% of the gravitational potential energy from the whole cloud. The feedback effect due to the outflows is minor in Taurus.

SiO masers are often observed in the near-circumstellar envelope of late-type evolved stars. The polarisation of the masers can be used as a probe of the magnetic field in this region, subject to maser polarisation radiative transfer model. Two main maser polarisation models have been developed for the weak Zeeman splitting case applicable to circumstellar SiO masers. Observational tests aimed at discriminating between these models were performed at maser component level, using VLBA observations of v=1 J=1-0, v=2 J=1-0 and v=1 J=2-1 SiO masers towards the high-luminosity source VY CMa.

In this paper, we introduce two compact, large-throughput CMB polarimeter designs (POLAR1 and BICEP3). These pathfinder experiments will pave the way for a comprehensive multi-frequency South Pole B-mode survey that, when jointly analyzed with arcminute-scale polarization data, can conclusively answer the question whether there is an appreciable fraction (>1%) of the primordial perturbations in the form of tensor modes (gravitational waves).

We investigate the MgII 2800 and CIV 1540 absorption features of the gas in the halo of a foreground QSO through the absorption imprinting on the spectra of a background QSO that is closely aligned with the nearest quasar. We present the results for 13 QSO pairs (0.7 < z < 2.2) that allow us to probe the gas at distances between 60 kpc and 120 kpc from the QSO nucleus. We identify absorption features associated with the foreground QSO in 7 out of 10 systems for MgII, and one out of 3 for CIV (see example in Fig. 1). At variance with the case of inactive and less massive galaxies we find that relatively strong (EW ~ 1 Ang) absorption features are present out to a radius of 100 kpc. This suggests that a large extended halo is associated with massive galaxies.

The comparison of these results with those for inactive (not hosting active black holes) galaxies (see e.g. Chen et al. 2010a) shows that the halo of QSOs is similar to that of inactive galaxies. In the observed sample we do not detect a significant enhancement of the absorption strengths, as it could be expected if the QSO nuclear activity were driven by intense gas accretion onto the black hole. Moreover along the line of sight of the QSO we do not detect any Mg II absorbers of the same strength of the transverse one. These results are in agreement with models that consider a non-isotropic emission of the QSO, which are hosted by massive gaseous halos.

There are faint contaminants near primary stars in the direct imaging of exoplanets. Our goal is to estimate statistically the ratio of exoplanets in the detected batch of point sources by calculating the fraction of contamination. In this study, we compared the detected number of stars with the number of contaminants predicted by our model. We found that the observed number of faint stars were fewer than the predicted results towards the Pleiades and GOODS-South field when the parameters of the conventional stellar distribution models were employed. We thus estimated new model parameters in correspondence to the results of the observations.