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Molecular clouds (MCs) in space are the birthplace of various molecular species. Chemical reactions occurring on the cryogenic surfaces of cosmic icy dust grains have been considered to play important roles in the formation of these species. Radical reactions are crucial because they often have low barriers and thus proceed even at low temperatures such as ∼10 K. Since the 2000s, laboratory experiments conducted under low-temperature, high-vacuum conditions that mimic MC environments have revealed the elementary physicochemical processes on icy dust grains. In this review, experiments conducted by our group in this context are explored, with a focus on radical reactions on the surface of icy dust analogues, leading to the formation of astronomically abundant molecules such as H2, H2O, H2CO, and CH3OH and deuterium fractionation processes. The development of highly sensitive, non-destructive methods for detecting adsorbates and their utilization for clarifying the behavior of free radicals on ice, which contribute to the formation of complex organic molecules, are also described.

Molecular clouds (MCs) in space are the birthplace of various molecular species. Chemical reactions occurring on the cryogenic surfaces of cosmic icy dust grains have been considered to play important roles in the formation of these species. Radical reactions are crucial because they often have low barriers and thus proceed even at low temperatures such as ∼10 K. Since the 2000s, laboratory experiments conducted under low-temperature, high-vacuum conditions that mimic MC environments have revealed the elementary physicochemical processes on icy dust grains. In this review, experiments conducted by our group in this context are explored, with a focus on radical reactions on the surface of icy dust analogues, leading to the formation of astronomically abundant molecules such as H2, H2O, H2CO, and CH3OH and deuterium fractionation processes. The development of highly sensitive, non-destructive methods for detecting adsorbates and their utilization for clarifying the behavior of free radicals on ice, which contribute to the formation of complex organic molecules, are also described.

© ESO. We would like to thank the anonymous referee as well as the Associate Editor M. Walmsley for fruitful comments and suggestions. We would like to thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma., The W51 complex hosts the supernova remnant W51C which is known to interact with the molecular clouds in the star forming region W51B. In addition, a possible pulsar wind nebula CXO J192318.5+140305 was found likely associated with the supernova remnant. Gamma-ray emission from this region was discovered by Fermi/LAT (between 0.2 and 50 GeV) and H. E. S. S. (>1 TeV). The spatial distribution of the events could not be used to pinpoint the location of the emission among the pulsar wind nebula, the supernova remnant shell and/or the molecular cloud. However, the modeling of the spectral energy distribution presented by the Fermi/LAT collaboration suggests a hadronic emission mechanism. The possibility that the gamma-ray emission from such an object is of hadronic origin can contribute to solvingthe long-standing problem of the contribution to galactic cosmic rays by supernova remnants. Aims. Our aim is to determine the morphology of the very-high-energy gamma-ray emission of W51 and measure its spectral properties. Methods. We performed observations of the W51 complex with the MAGIC telescopes for more than 50 h. The energy range accessible with MAGIC extends from 50 GeV to several TeV, allowing for the first spectral measurement at these energies. In addition, the good angular resolution in the medium (few hundred GeV) to high (above 1 TeV) energies allow us to perform morphological studies. We look for underlying structures by means of detailed morphological studies. Multi-wavelength data from this source have been sampled to model the emission with both leptonic and hadronic processes. Results. We detect an extended emission of very-high-energy gamma rays, with a significance of 11 standard deviations. We extend the spectrum from the highest Fermi/LAT energies to similar to 5 TeV and find that it follows a single power law with an index of 2.58 +/- 0.07(stat) +/- 0.22(syst). The main part of the emission coincides with the shocked cloud region, while we find a feat, German BMBF, German MPG, Italian INFN, Swiss National Fund SNF, Spanish MICINN, Marie Curie program, Bulgarian NSF, Academy of Finland, YIP of the Helmholtz Gemeinschaft, DFG Cluster of Excelle, DFG Collaborative Research Centers, Polish MNiSzW, National Science Foundation, MultiDark, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

© The American Astronomical Society. We would like to thank the IAC for the excellent working conditions at the Observatory de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, and the Spanish CICYT is gratefully acknowledged. This work was also supported by ETH research grant TH 34/04 3 and the Polish MNiI grant 1P03D01028., We report the detection of a new source of very high energy (VHE; E-gamma >= 100 GeV) gamma- ray emission located close to the Galactic plane, MAGIC J0616 + 225, which is spatially coincident with supernova remnant IC 443. The observations were carried out with the MAGIC telescope in the periods 2005 December-2006 January and 2006 December-2007 January. Here we present results from this source, leading to a VHE gamma-ray signal with a statistical significance of 5.7 sigma in the 2006/2007 data and a measured differential gamma-ray flux consistent with a power law, described as dN(gamma)/(dA dt dE) = (1.0 +/- 0.2) x 10(-11) (E/0.4 TeV)(-3.1 +/- 0.3) cm(-2) s(-1) TeV-1. We briefly discuss the observational technique used and the procedure implemented for the data analysis. The results are placed in the context of the multiwavelength emission and the molecular environment found in the region of IC 443., German BMBF, German MPG, Italian INFN, Spanish CICYT, ETH, Polish MNiI, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

This article has been accepted for publication in Monthly notices of the Royal Astronomical Society © 2013 MNRAS. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. MAL-G and JL-S acknowledge support by the Spanish Ministerio de Ciencía e Innovación under grant AYA2008-06423-C03-03. JFA-C is a researcher of the CONICET and acknowledges support by grant PICT 2007-02177 (SecyT). PGP-G acknowledges support from the Spanish Programa Nacional de Astronomía y Astrofísica under grants AYA2009-10368 and AYA2009-07723-E. We would like to acknowledge the anonymous referee for a fruitful discussion about the results of this work. His/her comments on the text content have allowed us to notoriously improve this manuscript., Nearby star-forming regions are ideal laboratories to study high-energy emission of different stellar populations, from very massive stars to brown dwarfs. NGC 2023 is a reflection nebula situated to the south of the Flame Nebula (NGC 2024) and at the edge of the H II region IC 434, which also contains the Horsehead Nebula (Barnard 33). NGC 2023, NGC 2024, Barnard 33 and the surroundings of the O-type supergiant star zeta Ori constitute the south part of the Orion B molecular complex. In this work, we present a comprehensive study of X-ray emitters in the region of NGC 2023 and its surroundings. We combine optical and infrared data to determine physical properties (mass, temperature, luminosity and the presence of accretion discs) of the stars detected in an XMM-Newton observation. This study has allowed us to analyse spectral energy distribution of these stars for the first time and determine their evolutionary stage. Properties of the X-ray emitting plasma of these stars are compared to those found in other nearby star-forming regions. The results indicate that the stars that are being formed in this region have characteristics, in terms of physical properties and luminosity function, similar to those found in the Taurus-Auriga molecular complex., Spanish Ministerio de Ciencía e Innovación, SecyT, Spanish Programa Nacional de Astronomía y Astrofísica, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

An optical study (high resolution images and long-slit spectra in the Her range) of the Serpens reflection nebula (SRN) is presented. The SRN is a bipolar nebula illuminated by the low mass pre-main-sequence (PMS) star Serpens/SVS 2. The Ho profile of Serpens/SVS 2 is shown to be very broad (the width at a 10% of the peak intensity is 13.1 Angstrom (similar to 600 km/s)). The profile has three emission peaks centered at -137, 5 and 100 km/s. The relative strength of the peaks varies with the slit orientation. The blue and redshifted components have similar intensities at low inclinations (PA = -55 degrees and PA = -30 degrees) while at high inclinations the blueshifted component is weaker than the redshifted suggesting a significant contribution of absorption by low latitude outflowing gas. These profiles could be produced in a rotating, latitude dependent wind with the outflow axis parallel to the disk axis. The nebular H alpha profile is double peaked; it has a blue and a redshifted component at the same velocities as the star. The profile shows no significant variations along a given PA; the emission is best explained by single scattering of the stellar radiation. The absence of the 0-velocity emission component is suggestive of the presence of warm absorbing gas within a few stellar radii. There are several knots of gas and dust embedded within the north-western (NW) nebular lobe. These knots are connected by a faint emission, defining a helical path around the major axis of the nebula. This area is also characterized by an unusually large polarization that reaches a 30-40% at 0.95 mu m that is consistent with a concentration of large and reflecting dust grains that are presumably ice coated carbon grains. This region coincides with a ridge of hot (T similar or equal to 35 K) dust detected by IRAS along: the major axis of the SRN., Unidad Deptal. de Astronomía y Geodesia, Fac. de Ciencias Matemáticas, TRUE, pub

© 2009. The American Astronomical Society. All rights reserved. We are grateful to the anonymous referee, J. F. Albacete Colombo, and J. Sánz Forcada for helpful discussion and advice. Financial support was provided by the Universidad Complutense de Madrid, the Comunidad Autónoma de Madrid, the Spanish Ministerio Educación y Ciencia, and the European Social Fund under grants: AyA200502750, AyA2005-04286, AyA2005-24102-E, AyA2008-06423C03-03, AyA2008-00695, PRICITS-0505/ESP-0237, and CSD2006-0070. This research has made use of the SIMBAD, operated at Centre de Données astronomiques de Strasbourg, France, and the NASA's Astrophysics Data System., We used the Aladin Virtual Observatory tool and High Resolution Imager ROSAT archival data to search for X-ray variability in scale of days in 23 young stars in the sigma Orionis cluster and a background galaxy. Five stars displayed unambiguous flares and had probabilities p(var) >> 99% of being actual variables. Two of the detected flares were violent and long lasting, with maximum duration of six days and amplitude of eight times above the quiescent level. We classified another four stars as possible X-ray variables, including the binary system formed by the B2Vp star sigma Ori E and its close late-type companion. This makes a minimum frequency of high-amplitude X-ray variability in excess of a day of 39% among sigma Orionis stars. The incidence of this kind of X-ray variability seems to be lower among classical T Tauri stars with mid-infrared flux excesses than among fast-rotating, disk-less young stars., Universidad Complutense de Madrid, Comunidad Autónoma de Madrid, Spanish Ministerio Educación y Ciencia, European Social Fund, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

© The Royal Astronomical Society. This work has been partially funded by the Ministry of Science and Innovation of Spain through grant: AYA2011-29754-C03-C01 and AYA2011-29754-C03-C03. This paper is based on data obtained by the NASA mission GALEX., The Taurus-Aurigamolecular complex (TMC) is the main laboratory for the study of low-mass star formation. The density and properties of interstellar dust are expected to vary across the TMC. These variations trace important processes such as dust nucleation or the magnetic field coupling with the cloud. In this paper, we show how the combination of near ultraviolet (NUV) and infrared (IR) photometry can be used to derive the strength of the 2175 Å bump and thus any enhancement in the abundance of small dust grains and polycyclic aromatic hydrocarbons in the dust grains size distribution. This technique is applied to the envelope of the TMC, mapped by the GALEXAll Sky Survey (AIS). Ultraviolet and IR photometric data have been retrieved from the GALEX-AIS and the 2MASS catalogues. NUV and K-band star counts have been used to identify the areas in the cloud envelope where the 2175 Å bump is weaker than in the diffuse interstellar medium namely, the low column density extensions of L1495, L1498 and L1524 in Taurus, L1545, L1548, L1519, L1513 in Auriga and L1482-83 in the California region. This finding agrees with previous results on dust evolution derived from Spitzer data and suggests that dust grains begin to decouple from the environmental Galactic magnetic field already in the envelope., Ministerio de Ciencia e Innovación (MCINN), España, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Molecular clouds (MCs) in space are the birthplace of various molecular species. Chemical reactions occurring on the cryogenic surfaces of cosmic icy dust grains have been considered to play important roles in the formation of these species. Radical reactions are crucial because they often have low barriers and thus proceed even at low temperatures such as ∼10 K. Since the 2000s, laboratory experiments conducted under low-temperature, high-vacuum conditions that mimic MC environments have revealed the elementary physicochemical processes on icy dust grains. In this review, experiments conducted by our group in this context are explored, with a focus on radical reactions on the surface of icy dust analogues, leading to the formation of astronomically abundant molecules such as H2, H2O, H2CO, and CH3OH and deuterium fractionation processes. The development of highly sensitive, non-destructive methods for detecting adsorbates and their utilization for clarifying the behavior of free radicals on ice, which contribute to the formation of complex organic molecules, are also described.