The Infrared Camera (IRC) onboard AKARI has a near-infrared (2--5μm) spectroscopic capability with high sensitivity that allows us to study the major ice components in various objects. In particular, H2O and CO2 ice absorption features have been detected towards nearby galaxies, including several young stellar objects (YSOs) in the Large Magellanic Cloud (LMC), as well as a number of HII region-PDR complexes for the first time by IRC spectroscopy. While observations in the LMC show a high ratio (~0.34) of the CO2 to H2O ice column densities, the ratios in Galactic HII-region-PDR complexes are in the range of 0.1--0.2, being compatible with those found in Galactic massive YSOs in previous studies. The good correlation supports concurrent formation of the two ice species on the grain surface and the higher ratio in the low-metallicity LMC suggests possible environmental effects in the formation process.

Long gamma-ray bursts (LGRBs) are associated to the deaths of massive stars and could thus be used as a potentially powerful tool to trace cosmic star formation. However the conditions needed to produce a LGRBs may introduce a bias in the LGRB rate versus star formation rate (SFR) relation (called LGRB efficiency hereafter).

We have undertaken a study of the properties of the host galaxies of the BAT6 complete sample of LGRB to improve our knowledge on the LGRB efficiency, its redshift evolution, and the factor affecting it. This is the base to properly use LGRBs as SFR tracers.

We show that at z < 1 LGRBs are not direct SFR tracers because they tend to avoid high-metallicity galaxies. The use of the BAT6 complete sample keeps this result from being affected by possible biases that could have influenced past results based on incomplete samples. The preference for low (but not extremely low) metallicities can be a consequence of the particular conditions needed for the progenitor star to produce a GRB.

We use 3.6 μm imaging from the S4G survey to characterize the typical stellar density profiles (Σ*) and bars as a function of fundamental galaxy parameters (e.g. the total stellar mass M*), providing observational constraints for galaxy simulation models to be compared with. We rescale galaxy images to a common frame determined by the size in physical units, by their disk scalelength, or by their bar size and orientation. We stack the resized images to obtain statistically representative average stellar disks and bars. For a given M* bin (≥ 109M⊙), we find a significant difference in the stellar density profiles of barred and non-barred systems that gives evidence for bar-induced secular evolution of disk galaxies: (i) disks in barred galaxies show larger scalelengths and fainter extrapolated central surface brightnesses, (ii) the mean surface brightness profiles of barred and non-barred galaxies intersect each other slightly beyond the mean bar length, most likely at the bar corotation, and (iii) the central mass concentration of barred galaxies is larger (by almost a factor 2 when T < 5) than in their non-barred counterparts. We also show that early- and intermediate-type spirals (0 ≤ T < 5) host intrinsically narrower bars than the later types and S0s, whose bars are oval-shaped. We show a clear correlation between galaxy family and bar ellipticity.

We present results of Herschel PACS imaging spectroscopy data toward ten massive young stellar objects taken as part of the WISH project. Our sample consists of four high mass protostellar objects (HMPOs), two hot molecular cores (HMCs), and four ultracompact HII regions (UCHIIs), and the spectra cover a broad range of wavelengths (55 to 210 μm) imaged over an ~50” field with 5×5 spaxels. By fitting the continua utilizing a modified black-body formula we estimate mass-weighted dust temperature and column density distributions of warm dust and find that UCHII regions are hottest and HMCs are most deeply embedded. We also estimate rotational temperature and column density distributions of warm CO gas using the rotational diagram analysis, which are comparable over targets in contrast to continuum results. By comparing high J CO line fluxes to the RATRAN estimates of centrally heated envelope models, we find that majority of warm CO originates from bipolar outflow shocks.

We aim at characterizing SN 2013dx, associated with GRB 130702A, and their environment, through ground-based observational campaigns in the optical-IR band. We infer a synthesized 56Ni mass of ~0.2 M⊙, a photospheric velocity of the ejected material declining from ~ 2.7 × 104 km s−1 at 8 rest frame days from the explosion, to ~ 3.5× 103 km s−1 at 40 days, a kinetic energy of ~ 35 × 1051 erg, an ejected mass of ~ 7 M⊙ and a progenitor mass of ~ 25-30 M⊙. We also find that the host belongs to a group of galaxies, an unprecedented finding for a GRB-associated SN and, to our knowledge, for long GRBs in general.

We use a 200 h−1Mpc cosmological hydrodynamical simulation to examine the alignments of galaxies with respect to the host halo. We do separate study for the different components of the halo, such as stars, gas and dark matter. We show that angular momentum of gas is more aligned with the angular momentum of host halo compared with the stellar component.

Galaxies in group and cluster environments are subject to ram pressure stripping by the hot intracluster medium, resulting in gas loss and the eventual suppression of star formation. Recent Chandra observations of galaxies in group and cluster environments show that 60 - 80% of these galaxies have compact (1-4 kpc), hot (~ 1 keV) X-ray coronae centered on their cores. These coronae have survived stripping and evaporation in the cluster, and their long-term survival poses a test of our understanding of the physical processes in the ICM. In this poster, I summarize results from Vijayaraghavan & Ricker (2015), where we simulated the evolution of populations of galaxies and their hot coronal gas in group and cluster environments, and evaluated their detectability with existing and future X-ray catalogs.

Barlenses are morphological features present in barred galaxies with morphological types between S0 and Sb. Recently, they have been suggested to be the more face-on counterparts of the boxy/peanut bulges generally observed in edge-on galaxies. In this work we test this idea by looking at the orientations and colors of barlenses, and by comparing them with those of the bars and disks in the same galaxies. We find that barlenses have colors which are similar to those of bars, and also similar to those of elliptical galaxies.

Comet composition and properties provide information on chemical and physical processes that occurred in the early Solar system, 4.6 Gyr ago. The study of comets and of star-forming regions both help for a better understanding of the formation of planetary systems. A review of our present knowledge of cometary composition is presented. We also discuss laboratory studies that would be helpful for data analysis.

As part of the Herschel Gould Belt Survey (HGBS), the Ophiuchus molecular cloud was imaged in the submillimeter range. Here, we summarize and briefly discuss the main results.

FeLoBAL quasars may be an early evolutionary stage of merger-triggered quasar activity. We test this hypothesis using HST imaging of four FeLoBAL quasars. The host galaxy colors are consistent with early-type quiescent galaxies or heavily-obscured starbursts.

Since 2009 X-shooter has collected spectroscopy of over 80 gamma-ray burst afterglows with redshifts ranging from 0.05 to 6.3. Thanks to its efficiency, broad wavelength coverage (3,000 to 24,800 Å), and intermediate spectral resolution (R~8,000) it has become the most efficient tool for gamma-ray burst afterglow spectroscopy. In this Focus Meeting we presented the sample and some preliminary results of the analysis of absorption systems.

We found the alignement of elongated clusters of BM type I and III (the excess of small values of the Δθ angles is observed), having range till about 60 h−1Mpc. The first one is probably connected with the origin of supergiant galaxy, while the second one with environmental effects in clusters, originated on the long filament or plane.

We present new deep co-adds of data taken within Stripe 82 of the Sloan Digital Sky Survey (SDSS), especially stacked to reach the faintest surface brightness limits of this data set. Our reduction puts special emphasis on preserving the characteristics of the background (sky + diffuse light) in the input images using a non-aggressive sky subtraction strategy, resulting in an exquisite quality on extremely faint structures. The IAC Stripe 82 co-adds offer a rather unique possibility to study the low surface brightness Universe like stellar haloes and disc truncations, low surface brightness, tidal galactic interactions, extremely faint dwarf galaxies, intra-cluster light or diffuse light from galactic dust. The imaging data is publicly available at http://www.iac.es/proyecto/stripe82/.

We tested the spatial distribution of UCDs and GCs in the halo of NGC 1399 in the Fornax cluster. In particular we tried to find out if globular clusters are more abundant in the vicinity of UCDs than what is expected from their global distribution. A local overabundance of globular clusters was found around UCDs on a scale of 1 kpc compared to what is expected from the large scale distribution of globulars in the host galaxy. This effect is stronger for the metal-poor blue GCs and weaker for the red GCs. An explanation for these clustered globulars is either that they are the remains of a GC system of an ancestor dwarf galaxy before it was stripped to its nucleus, which appears as UCD today. Alternatively these clustered GCs could have been originally part of a super star cluster complex.

We look at applications of recent work in theoretical and experimental spectroscopy for the analysis of IR data concerning giant planets, Titan and possibly exoplanets.

Throughout the past decade, significant advances have been made in the size and scope of large-scale spectroscopic surveys, allowing for the opportunity to study in-depth the formation history of the Milky Way. Using the fourth data release of the RAdial Velocity Experiment (RAVE), we study the age-metallicity-velocity space of ~ 100,000 FGK stars in the extended solar neighborhood in order to explore evolutionary processes. Combining these three parameters, we better constrain our understanding of these interconnected, fundamental processes.

We constructed and studied the luminosity function of 6188 galaxy clusters. This was performed by counting brightness of galaxies belonging to clusters in the PF catalogue, taking galaxy data from MRSS. Our result shows that the investigated structures are characterized by a luminosity function different from that of optical galaxies and radiogalaxies (Machalski & Godłowski 2000). The implications of this result for theories of galaxy formation are briefly discussed.

We characterise steady, one-dimensional fast and slow magnetohydrodynamic (MHD) shocks using a two-fluid model. Fast MHD shocks are magnetically driven, forcing ions to stream through the neutral gas ahead of the shock front. This magnetic precursor heats the gas sufficiently to create a large, warm transition zone where all fluid variables only weakly change in the shock front. In contrast, slow MHD shocks are driven by gas pressure where neutral species collide with ion species in a thin hot slab that closely resembles an ordinary gas dynamic shock.

We computed observational diagnostics for fast and slow shocks at velocities vs=2–4 km/s and preshock Hydrogen nuclei densities nH = 102-4 cm−3. We followed the abundances of molecules relevant for a simple oxygen chemistry and include cooling by CO, H2 and H2O. Estimates of intensities of 12CO rotational lines show that high-J lines, above J = 6 → 5, are more strongly excited in slow MHD shocks.

The decomposition of the 21 cm rotation curve of galaxies into contribution from the disk and dark halo depends on the adopted mass to light ratio (M/L) of the disk. Given the vertical velocity dispersion (σz) of stars in the disk and its scale height (h), the disk surface density and hence the M/L can be estimated. Earlier works have used this technique to conclude that galaxy disks are submaximal. Here we address an important conceptual problem: σz and h must pertain to the same population. Our analysis concludes that previous studies underestimate the disk surface mass density by ~ 2, sufficient to make a maximal disk for M74 appear like a submaximal disk.