The bimodality in galaxy properties has been observed at low and high redshift, with a clear distinction between star-forming galaxies in the blue cloud and passively evolving objects in the red sequence; the absence of galaxies with intermediate properties indicates that the quenching of star formation and subsequent transition between populations must happen rapidly. In this work, we present a study of over 100 transiting galaxies in the so-called “green valley” at intermediate redshifts (z ~ 0.8). By using very deep spectroscopy with the DEIMOS instrument at the Keck telescope, we are able to infer the star formation histories of these objects and measure the stellar mass flux density transiting from the blue cloud to the red sequence when the Universe was half its current age. Our results indicate that the process happened more rapidly, affecting more massive galaxies in the past, suggesting a top-down scenario whereby the massive end of the red sequence assembles first. This represents another aspect of downsizing, with the mass flux density moving towards smaller galaxies in recent times.

A diverse range of terrestrial planet compositions is believed to exist within known extrasolar planetary systems, ranging from those that are relatively Earth-like to those that are highly unusual, dominated by species such as refractory elements (Al and Ca) or C (as pure C, TiC and SiC)(Bond et al. 2010b). However, all prior simulations have ignored the impact that giant planet migration during planetary accretion may have on the final terrestrial planetary composition. Here, we combined chemical equilibrium models of the disk around five known planetary host stars (Solar, HD4203, HD19994, HD213240 and Gl777) with dynamical models of terrestrial planet formation incorporating various degrees of giant planet migration. Giant planet migration is found to drastically impact terrestrial planet composition by 1) increasing the amount of Mg-silicate species present in the final body; and 2) dramatically increasing the efficiency and amount of water delivered to the terrestrial bodies during their formation process.

We present a brief review of Very Long Baseline Array (VLBA) observations of water masers in the so-called water fountain pre-planetary nebulae, and report on new VLBA and Very Large Array (VLA) data for the water masers in the prototypical water fountain source IRAS16342–3814, taken approximately monthly in 2008–2009. A new and very strong water maser is found at an LSR velocity of −3 km s−1, which is offset from the central (likely stellar) velocity. The new VLBA observations still show a similar general structure as was observed in 2002, but there are details which are difficult to explain.

In this work we discuss the turbulent evolution of molecular clouds and the formation of dense structures within. Typically, the clumps evolution occurs apart from the secular evolution of the turbulent mother cloud due to its high density and large inertia. Despite of current theoretical assumptions we show, by means of numerical simulations, that the clump lifetimes are greater than previously thought by more than an order of magnitude. The presence of dense and long-lived clumps modifies the spectral line profiles of clouds, which are strongly related to the determination of Larson's relations. We address the main modifications of these if a realistic distribution of dense structures is taken into account.

Water fountains are evolved stars showing water masers with velocity spanning more than ~100 km/s. They usually appear at the end of the Asymptotic Giant Branch (AGB) phase or at the beginning of the post-AGB phase, and their masers trace the first manifestation of axisymmetric collimated mass-loss. For the first time, masers with water fountain characteristics have been detected towards a PN (IRAS 15103–5754), which might require a revision of the current theories about jet formation and survival times. IRAS 15103-5754 was observed using the ATCA interferometer at 22 GHz (both continuum and water maser). The main results of these observations are summarized here. The evolutionary classification of this object is also discussed.

Recent observational and theoretical results suggest that the production rates and luminosities of high-mass X-ray binaries depend on metallicity. To test this prediction, we combine HMXB population synthesis results with numerical simulations of galaxy formation to produce synthetic populations of HMXBs in star-forming galaxies, and compare the model predictions to observations of HMXB populations in nearby and high-redshift galaxies. Our models show a fair agreement with observations only when the HMXB production and luminosities are assumed to depend strongly on metallicity.

In this proceeding paper, we discuss the important underlying connections between the faint end slope αs of the stellar mass function of star-forming galaxies, the logarithmic slope β of the sSFR-mass relation and merging through the continuity approach, as we introduced in Peng et al. (2010, hereafter P10) and (2012, hereafter P12).

We use the adaptive mesh refinement code RAMSES to model the formation of protoplanetary disks in realistic star formation environments. The resolution scales over up to 29 powers of two (~ 9 orders of magnitude) covering a range from outer scales of 40 pc to inner scales of 0.015 AU. The accretion rate from a 1.5 solar mass envelope peaks near 10−4 M⊙ about 6 kyr after sink particle formation and then decays approximately exponentially, reaching 10−6 M⊙ in 100 kyr. The models suggest universal scalings of physical properties with radius during the main accretion phase, with kinetic and / or magnetic energy in approximate balance with gravitational energy. Efficient accretion is made possible by the braking action of the magnetic field, which nevertheless allows a near-Keplerian disk to grow to a 100 AU size. The magnetic field strength ranges from more than 10 G at 0.1 AU to less than 1 mG at 100 AU, and drives a time dependent bipolar outflow, with a collimated jet and a broader disk wind.

Coronal mass ejections observed in the corona exhibit a three-part structure, with a leading bright front indicating dense plasma, a low density cavity thought to be a signature of the embedded magnetic flux rope, and the high density core likely containing cold, prominence material. When observed in-situ, as Interplanetary CMEs (or ICMEs), the presence of all three of these signatures remains elusive, with the prominence material rarely observed. We report on a comprehensive and long-term search for prominence material inside ICMEs as observed by the Solar Wind Ion Composition Spectrometer on the Advanced Composition Explorer. Using a novel data analysis process, we are able to identify traces of low charge state plasma created during prominence eruptions associated with ICMEs. We find that the likelihood of occurrence of cold material in the heliosphere is vastly lower than that observed in the corona but that conditions during the eruption do allow low charge ions to make it into the solar wind, preserving their expansion history. We discuss the implications of these findings.

There exists a special class of X-ray pulsars that exhibit very slow pulsation of Pspin > 1000 s in the high mass X-ray binaries (HMXBs). We have studied the temporal and spectral properties of these superslow pulsation neutron star binaries in hard X-ray bands with INTEGRAL observations. Long-term monitoring observations find spin period evolution of two sources: spin-down trend for 4U 2206+54 (Pspin ~ 5560 s with Ṗspin ~ 4.9 × 10−7 s s−1) and long-term spin-up trend for 2S 0114+65 (Pspin ~ 9600 s with Ṗspin ~ −1 × 10−6 s s−1) in the last 20 years. A Be X-ray transient, SXP 1062 (Pspin ~ 1062 s), also showed a fast spin-down rate of Ṗspin ~ 3 × 10−6 s s−1 during an outburst. These superslow pulsation neutron stars cannot be produced in the standard X-ray binary evolution model unless the neutron star has a much stronger surface magnetic field (B > 1014 G). The physical origin of the superslow spin period is still unclear. The possible origin and evolution channels of the superslow pulsation X-ray pulsars are discussed. Superslow pulsation X-ray pulsars could be younger X-ray binary systems, still in the fast evolution phase preceding the final equilibrium state. Alternatively, they could be a new class of neutron star system – accreting magnetars.

We present long term site testing statistics based on DIMM and GSM data obtained at Dome C, Antarctica. These data have been collected on the bright star Canopus since the end of 2003. We give values of the integrated turbulence parameters in the visible (wavelength 500 nm). The median value we obtained for the seeing are 1.2 arcsec, 2.0 arcsec and 0.8 arcsec at respective elevations of 8m, 3m and 20m above the ground. The isoplanatic angle median value is 4.0 arcsec and the median outer scale is 7.5m. We found that both the seeing and the isoplanatic angle exhibit a strong dependence with the season (the seeing is larger in winter while the isoplanatic angle is smaller).

The theory of mean-field galactic dynamos is generalized by allowing for a finite response time of the mean electromotive force (emf) to variations in the mean magnetic field and small-scale turbulence. A non-axisymmetric forcing of the dynamo by a spiral pattern (either stationary or transient) is invoked. The resulting magnetic spiral arms are phase-shifted from the spiral arms of the pattern by an angle 15°–40°, opposite to the sense of galactic rotation. Our findings may help to explain the phase shift between material and magnetic arms observed in NGC 6946 and other galaxies.

Infrared water line emission from protoplanetary disks, recently observed by the Spitzer and Herschel space telescopes, is thought to trace the surface layer of the inner to outer regions of the disks. We have modelled the water abundance profile and line emission, especially focusing on the effects of dust size growth and turbulent mixing. Comparison between model calculations and observations suggests a small grain model with turbulent mixing is preferred.

We study the correlations of rotation velocity and absolute magnitude with surface brightness for low surface brightness dwarf irregular galaxies (dIrrs). We find that isolated objects contribute most to the scatter in the Tully–Fisher relation (TFR). Excluding these extreme cases, we develop a three-parameter (luminosity, Hi line width at 20% of peak flux level, i.e., W20, effective surface brightness) TFR for 60 dIrrs (with revised Hubble type T > 8) in the Local Volume (LV) with Cepheid and tip-of-the-red-giant-branch distance measurements. The relation is applied to galaxies of the same morphological type with radial velocities vLG ≤ 3500 km s−1 in the Local Supercluster. We obtained surface photometry and determined structural parameters using sdss images. The rotational velocities and derived photometric parameters for most galaxies in small groups agree well with those corresponding to the three-parameter TFR. However, isolated galaxies appear to have systematically lower surface brightnesses and longer scale lengths for the same luminosity than galaxies in small groups. This may indicate on average twice larger Hi-to-optical disk size ratios for our sample of isolated dIrrs, because their Hi surface densities calculated using the optical diameters look normal.

We perform an unbiased search for outflows from YSOs along the Galactic Plane (GP). Our data has been taken as part of the UWISH2 survey (Froebrich et al. 2011). It uses as tracer the 1-0S(1) emission line of H2, and here we focus on a continuous 33 square degree sized region in Serpens and Aquila. We identify 130 outflows from which 94% are new discoveries. Thus, we increased the number of known MHOs by a factor of 15 in this area (Ioannidis & Froebrich 2012). The flux completeness limit for the flows is 3ċ10−18Wm−2. Typically, the known flows occupy the bright end of the flux distribution. Our survey thus increases the known integrated 1-0S(1) H2 flux from outflows only by a factor of two. We are able to assign possible driving sources to half of the outflows. Brighter MHOs are more likely to have a source candidate assigned to them.

Foreground star counts to GMCs associated with the outflows and the Besancon Galaxy model are used to determine distances. The method is calibrated using objects from the RMS survey. This allows us to estimate distances with a scatter of 25% (Ioannidis & Froebrich 2012). The spatial distribution of the outflows shows that they follow the GMC complexes in the GP. However, there are large areas with high extinction where no flows are detected. About 2/3 of the survey area is more or less devoid of outflows. The flows typically occur in groups of 3–5 members with a size of 5pc. The scale height of flows is ∼25–30pc, similar to young clusters and OB stars. The 1-0S(1) luminosities range from a few 10−4L⊙ to 0.1L⊙, ten times brighter than in nearby SF regions. Our sample is complete for objects brighter than 10−3L⊙ at 5kpc. This corresponds to HH211 behind AK = 1mag. The luminosity distribution of the outflows is a power law with N ∝ LH2−1.9 and the integrated luminosities indicate a Milky Way SF rate (averaged over a typical jet lifetime) of more than 0.4M⊙yr−1. The energy and momentum of the jets is insufficient to sustain the typical local turbulence levels in their parental clouds.

The projected jet length drops exponentially in number for longer jets. The fraction of parsec scale flows is 25%, twice as high as in nearby SF regions. A Monte-Carlo type model of jet speeds of 40–130kms−1 and ages between 4–20 × 103yrs can reproduce the length distribution. These lifetimes are an order of magnitude below estimates for the protostellar phase. For typical jet speeds the time gaps between the ejection of larger amounts of material are about 103yrs. According to the burst mode of SF models the creation of H2 knots is hence linked to low level fluctuations of the mass accretion rate and not FU-Ori type events. Their duty cycle is more in agreement with the total jet lifetime, which suggests these outburst as trigger (or stopping point or both) of a jet ejection phase. However, better constraints of the FU-Ori duty cycle and mechanism as well as more detailed models are required to draw any further conclusions.

Silicon monoxide maser emission has been detected in the circumstellar envelopes of many evolved stars. It is a good tracer of the wind dynamics within a few stellar radii of the central star. We investigated the polarization morphology in the circumstellar envelope of an AGB star, R Cas, by using the VLBA to map the linear and circular polarization of the v=1, J=1-0 SiO maser transition during 23 epochs over two stellar cycles. The average fractional circular polarization is a few percent. The average fractional linear polarization per epoch is 11–58%, but some isolated features exceed 100%, probably because the total intensity emission is smoother and more resolved-out. The maser electric polarization vector angle has a preferrential tendency to be either parallel or perpendicular to the radial direction to the star.

Present day massive (Mstellar > 1011 M⊙) galaxies are composed mostly of early-type objects. To ascertain whether this was also the case at higher redshift, we have compiled over a thousand massive galaxies at 0 < z < 3 with HST imaging and spectroscopic redshifts for the majority of them. We have also analyzed using 3D spectroscopy another sample of 10 massive galaxies at z = 1.4. Both works highlight the progressive change between a late-type/peculiar nature at z > 2 and a predominance of early-type morphologies only since z = 1.

The Vela pulsar, like many other young pulsars, undergoes occasional sudden “spin-ups” in rotational frequency known as glitches. These glitches are characterised by a sudden (less than 30s) rise in the rotation frequency accompanied by a jump in the spin-down. This is generally followed by rapidly decaying transients in the spin-down and a gradual linear recovery. This recovery provides insight into the internal structure of the neutron star.

The telescopes at HartRAO was been used to monitor the Vela pulsar almost daily from 1985 in order to monitor these glitches. The vast majority of these observations were made using the 26m antenna at 1.6 GHz and 2.3 Ghz. When the 26m antenna was offline due to a bearing failure for two years from 2008 the 15m MeerKAT prototype antenna was used to observe Vela.

During the entire monitoring campaign 10 large glitches have been observed. The majority of the glitches show a similar recovery pattern. We discuss the characteristics of this common recovery. We compare the standard glitch recovery to that predicted by a hydrodynamic model of the neutron star interior.

An exception to the standard glitch are the two glitches which occurred in 1994 separated by 32 days. This “double” glitch is unique amongst Vela glitches. The event is accompanied by typical transients in rotation frequency derivative but all of the long-term offset occurs at the first event and the rapidly-decaying transient is only seen with the second spin-up.

During an active star formation phase, it is conceivable that the turbulent level of a galaxy increases and consequently an increase in magnetic field by turbulent dynamo process. We point out that the thickness of the dynamo region is sensitive to the turbulent level. We examine the linear growth rate of three different dynamos, namely, αω, α2ω and α2 dynamos. We find that the dependence of the growth rate on turbulent level is quite different for different dynamos. Moreover, the growth rate is not necessary monotonic to turbulence level even in the linear regime.

The tip of the red giant branch (TRGB) is one of the most accurate distance indicators to galaxies in the Local Universe (for distances up to 8–10 Mpc). A distance accuracy as high as 5% can be achieved with the recently developed maximum-likelihood implementation of the TRGB method and modern calibrations. In this paper, we consider in detail TRGB distance determinations to nearby groups of galaxies (within 8 Mpc). We discuss the photometric accuracy and describe colour–magnitude-diagram features of nearby dwarf galaxies and their influence on the accuracy of distance determination. We have determined accurate structures of the two nearest galaxy groups, M81 and Cen A, using observations of galaxies in these groups with the Hubble Space Telescope's WFPC2 and ACS instruments. The new technique allows us to see new details in the distribution of galaxies in the Canes Venatici i Cloud.