Modeling and predicting the shape of the far-infrared to submillimeter emission in ultra-compact HII regions and cold clumps

Dust properties are very likely affected by the environment in which dust grains evolve. For instance, some analyses of cold clumps (7 K- 17 K) indicate that the aggregation process is favored in dense environments. However, studying warm (30 K-40 K) dust emission at long wavelength ($\lambda$$>$300 $\mu$m) has been limited because it is difficult to combine far infared-to-millimeter (FIR-to-mm) spectral coverage and high angular resolution for observations of warm dust grains. Using Herschel data from 70 to 500 $\mu$m, which are part of the Herschel infrared Galactic (Hi-GAL) survey combined with 1.1 mm data from the Bolocam Galactic Plane Survey (BGPS), we compared emission in two types of environments: ultra-compact HII (UCHII) regions, and cold molecular clumps (denoted as cold clumps). With this comparison we tested dust emission models in the FIR-to-mm domain that reproduce emission in the diffuse medium, in these two environments (UCHII regions and cold clumps). We also investigated their ability to predict the dust emission in our Galaxy. We determined the emission spectra in twelve UCHII regions and twelve cold clumps, and derived the dust temperature (T) using the recent two-level system (TLS) model with three sets of parameters and the so-called T-$\beta$ (temperature-dust emissvity index) phenomenological models, with $\beta$ set to 1.5, 2 and 2.5. We tested the applicability of the TLS model in warm regions for the first time. This analysis indicates distinct trends in the dust emission between cold and warm environments that are visible through changes in the dust emissivity index. However, with the use of standard parameters, the TLS model is able to reproduce the spectral behavior observed in cold and warm regions, from the change of the dust temperature alone, whereas a T-$\beta$ model requires $\beta$ to be known.Comment: Accepted for publication in A&A. 19 pages, 8 figures, 7 table

Distance to the SNR CTB 109/AXP 1E 2259+586 by HI absorption and self-absorption

We suggest a revised distance to the supernova remnant (SNR) G109.1-1.0 (CTB 109) and its associated anomalous X-ray pulsar (AXP) 1E 2259+586 by analyzing 21cm HI-line and 12CO-line spectra of CTB 109, HII region Sh 152, and the adjacent molecular cloud complex. CTB 109 has been established to be interacting with a large molecular cloud (recession velocity at v=-55 km s^-1). The highest radial velocities of absorption features towards CTB 109 (-56 km s^-1) and Sh 152 (-65 km s^-1) are larger than the recombination line velocity (-50 km s^-1) of Sh 152 demonstrating the velocity reversal within the Perseus arm. The molecular cloud has cold HI column density large enough to produce HI self-absorption (HISA) and HI narrow self-absorption (HINSA) if it was at the near side of the velocity reversal. Absence of both HISA and HINSA indicates that the cloud is at the far side of the velocity reversal within the Perseus Arm, so we obtain a distance for CTB 109 of 4+/-0.8 kpc. The new distance still leads to a normal explosion energy for CTB 109/AXP 1E 2259+586.Comment: 5 pages, 3 figures. Accepted by MNRAS Letter

Herschelobservations of the W3 GMC (II): clues to the formation of clusters of high-mass stars

The W3 giant molecular cloud is a prime target for investigating the formation of high-mass stars and clusters. This second study of W3 within the HOBYS Key Program provides a comparative analysis of subfields within W3 to further constrain the processes leading to the observed structures and stellar population. Probability density functions (PDFs) and cumulative mass distributions (CMDs) were created from dust column density maps, quantified as extinction AV. The shape of the PDF, typically represented with a lognormal function at low Av “breaking” to a power-law tail at high Av, is influenced by various processes including turbulence and selfgravity. The breaks can also be identified, often more readily, in the CMDs. The PDF break from lognormal (Av(SF)» 6–10 mag) appears to shift to higher Av by stellar feedback, so that high-mass star-forming regions tend to have higher PDF breaks. A second break at Av> 50 mag traces structures formed or influenced by a dynamic process. Because such a process has been suggested to drive high-mass star formation in W3, this second break might then identify regions with potential for hosting high-mass stars/clusters. Stellar feedback appears to be a major mechanism driving the local evolution and state of regions within W3. A high initial star formation efficiency in a dense medium could result in a self-enhancing process, leading to more compression and favorable star formation conditions (e.g., colliding flows), a richer stellar content, and massive stars. This scenario would be compatible with the “convergent constructive feedback” model introduced in our previous Herschel study

Galactic cold cores. VI. Dust opacity spectral index

Context. The Galactic Cold Cores project has carried out Herschel photometric observations of 116 fields where the Planck survey has found signs of cold dust emission. The fields contain sources in different environments and different phases of star formation. Previous studies have revealed variations in their dust submillimetre opacity. Aims. The aim is to measure the value of dust opacity spectral index and to understand its variations spatially and with respect to other parameters, such as temperature, column density, and Galactic location. Methods. The dust opacity spectral index β and the dust colour temperature T are derived using Herschel and Planck data. The relation between β and T is examined for the whole sample and inside individual fields. Results. Based on IRAS and Planck data, the fields are characterised by a median colour temperature of 16.1 K and a median opacity spectral index of β = 1.84. The values are not correlated with Galactic longitude. We observe a clear T–β anti-correlation. In Herschel observations, constrained at lower resolution by Planck data, the variations follow the column density structure and β_(FIR) can rise to ~2.2 in individual clumps. The highest values are found in starless clumps. The Planck 217 GHz band shows a systematic excess that is not restricted to cold clumps and is thus consistent with a general flattening of the dust emission spectrum at millimetre wavelengths. When fitted separately below and above 700 μm, the median spectral index values are β_(FIR) ~ 1.91 and β(mm) ~ 1.66. Conclusions. The spectral index changes as a function of column density and wavelength. The comparison of different data sets and the examination of possible error sources show that our results are robust. However, β variations are partly masked by temperature gradients and the changes in the intrinsic grain properties may be even greater

Microrreservas marinas artificiales en la línea de costa. Hacia un nuevo modelo de gestión de la biodiversidad en áreas litorales

Recientemente se ha propuesto a la comunidad científica la nueva figura de protección MRMA (Microrreserva Marina Artificial; AMMR en inglés) la cual también ha sido formalmente solicitada a la UNESCO para que esta institución considere reconocerla y consecuentemente, validarla. Se expone la contribución de las MRMAs a la preservación de especies protegidas, particularmente a las consideradas en peligro de extinción que propendan, de forma natural, a establecerse en escolleras y diques de abrigo de instalaciones costeras. Se mencionan las especies protegidas localizadas en las MRMAs, así como sus figuras de protección y disposiciones oficiales que les conciernen. Se exponen criterios generales de designación de MRMAs, posibles vías de solución ante problemas previsibles que puedan surgir (entendimiento entre administraciones, calidad de aguas, medidas de contingencia ante vertidos accidentales, etc.) y se deja entrever las potencialidades de las MRMAs como activo ecológico, medioambiental, urbanístico y educativo, así como el futuro papel que desempeñarán las MRMAs en la gestión del medio litoral y en el campo de la biología de la conservación. Finalmente, se establece una revisión de la legislación actual que más pudiera concernirles, destacándose los aspectos más importantes que en ellas pudieran influir. Al respecto, se destaca que ley 41/2010 de Protección del Medio Marino (Artº 26) establece que podrán formar parte de la red de Áreas Marinas Protegidas “ las áreas protegidas por instrumentos internacionales, sin perjuicio de que su declaración y gestión se ajustará a lo dispuesto en su correspondiente normativa internacional ” por lo que, si la nueva figura de protección “Microrreserva Marina Artificial” consiguiera marchamo UNESCO, aquélla podría incorporarse a la legislación española sin ninguna dificultad especial

Galactic cold cores VIII. Filament formation and evolution : Filament properties in context with evolutionary models

Context. The onset of star formation is intimately linked with the presence of massive unstable filamentary structures. These filaments are therefore key for theoretical models that aim to reproduce the observed characteristics of the star formation process in the Galaxy. Aims. As part of the filament study carried out by the Herschel Galactic Cold Cores Key Programme, here we study and discuss the filament properties presented in GCC VII (Paper I) in context with theoretical models of filament formation and evolution. Methods. A conservatively selected sample of filaments located at a distance D <500 pc was extracted from the GCC fields with the getfilaments algorithm. The physical structure of the filaments was quantified according to two main components: the central (Gaussian) region of the filament (core component), and the power-law-like region dominating the filament column density profile at larger radii (wing component). The properties and behaviour of these components relative to the total linear mass density of the filament and the column density of its environment were compared with the predictions from theoretical models describing the evolution of filaments under gravity-dominated conditions. Results. The feasibility of a transition from a subcritical to supercritical state by accretion at any given time is dependent on the combined effect of filament intrinsic properties and environmental conditions. Reasonably self-gravitating (high M-line,M-core) filaments in dense environments (Av greater than or similar to 3 mag) can become supercritical on timescales of t similar to 1 Myr by accreting mass at constant or decreasing width. The trend of increasing M-line,M-tot (M-line,M-core and M-line,M-wing) and ridge A(v) with background for the filament population also indicates that the precursors of star-forming filaments evolve coevally with their environment. The simultaneous increase of environment and filament Av explains the observed association between dense environments and high Mlille,co values, and it argues against filaments remaining in constant single-pressure equilibrium states. The simultaneous growth of filament and background in locations with efficient mass assembly, predicted in numerical models of filaments in collapsing clouds, presents a suitable scenario for the fulfillment of the combined filament mass-environment criterium that is in quantitative agreement with Herschel observations.Peer reviewe

Correlation of gas dynamics and dust in the evolved filament G82.65-02.00

Context. The combination of line and continuum observations can provide vital insight into the formation and fragmentation of filaments and the initial conditions for star formation. We have carried out line observations to map the kinematics of an evolved, actively star forming filament G82.65-2.00. The filament was first identified from the Planck data as a region of particularly cold dust emission and was mapped at 100-500 mu m as a part of the Herschel key program Galactic Cold Cores. The Herschel observations cover the central part of the filament, corresponding to a filament length of similar to 12 pc at the assumed distance of 620 pc.& para;& para;Aims. CO observations show that the filament has an intriguing velocity field with several velocity components around the filament. In this paper, we study the velocity structure in detail, to quantify possible mass accretion rate onto the filament, and study the masses of the cold cores located in the filament.& para;& para;Methods. We have carried out line observations of several molecules, including CO isotopologues, HCO+, HCN, and CS with the Osaka 1.85 m telescope and the Nobeyama 45 m telescope. The spectral line data are used to derive velocity and column density information.& para;& para;Results. The observations reveal several velocity components in the field, with strongest line emission concentrated to velocity range similar to[3,5] km s(-1). The column density of molecular hydrogen along the filament varies from 1.0 to 2.3 x 10(22) cm(2). We have examined six cold clumps from the central part of the filament. The clumps have masses in the range 10-20 M circle dot (similar to 70 M circle dot in total) and are close to or above the virial mass. Furthermore, the main filament is heavily fragmented and most of the substructures have a mass lower than or close to the virial mass, suggesting that the filament is dispersing as a whole. Position-velocity maps of (CO)-C-12 and (CO)-C-13 lines indicate that at least one of the striations is kinematically connected to two of the clumps, potentially indicating mass accretion from the striation onto the main filament. We tentatively estimate the accretion rate to be M = 2.23 x 10(-6) M circle dot/yr.& para;& para;Conclusions. Our line observations have revealed two or possibly three velocity components connected to the filament G82.65-2.00 and putative signs of mass accretion onto the filament. The line observations combined with Herschel and WISE maps suggest a possible collision between two cloud components.Peer reviewe

Using the MitoB method to assess levels of reactive oxygen species in ecological studies of oxidative stress

In recent years evolutionary ecologists have become increasingly interested in the effects of reactive oxygen species (ROS) on the life-histories of animals. ROS levels have mostly been inferred indirectly due to the limitations of estimating ROS from in vitro methods. However, measuring ROS (hydrogen peroxide, H2O2) content in vivo is now possible using the MitoB probe. Here, we extend and refine the MitoB method to make it suitable for ecological studies of oxidative stress using the brown trout Salmo trutta as model. The MitoB method allows an evaluation of H2O2 levels in living organisms over a timescale from hours to days. The method is flexible with regard to the duration of exposure and initial concentration of the MitoB probe, and there is no transfer of the MitoB probe between fish. H2O2 levels were consistent across subsamples of the same liver but differed between muscle subsamples and between tissues of the same animal. The MitoB method provides a convenient method for measuring ROS levels in living animals over a significant period of time. Given its wide range of possible applications, it opens the opportunity to study the role of ROS in mediating life history trade-offs in ecological settings

Far-infrared observations of a massive cluster forming in the Monoceros R2 filament hub

We present far-infrared observations of Monoceros R2 (a giant molecular cloud at approximately 830 pc distance, containing several sites of active star formation), as observed at 70 μm, 160 μm, 250 μm, 350 μm, and 500 μm by the Photodetector Array Camera and Spectrometer (PACS) and Spectral and Photometric Imaging Receiver (SPIRE) instruments on the Herschel Space Observatory as part of the Herschel imaging survey of OB young stellar objects (HOBYS) Key programme. The Herschel data are complemented by SCUBA-2 data in the submillimetre range, and WISE and Spitzer data in the mid-infrared. In addition, C18O data from the IRAM 30-m Telescope are presented, and used for kinematic information. Sources were extracted from the maps with getsources, and from the fluxes measured, spectral energy distributions were constructed, allowing measurements of source mass and dust temperature. Of 177 Herschel sources robustly detected in the region (a detection with high signal-to-noise and low axis ratio at multiple wavelengths), including protostars and starless cores, 29 are found in a filamentary hub at the centre of the region (a little over 1% of the observed area). These objects are on average smaller, more massive, and more luminous than those in the surrounding regions (which together suggest that they are at a later stage of evolution), a result that cannot be explained entirely by selection effects. These results suggest a picture in which the hub may have begun star formation at a point significantly earlier than the outer regions, possibly forming as a result of feedback from earlier star formation. Furthermore, the hub may be sustaining its star formation by accreting material from the surrounding filaments