Antifreeze in the hot core of Orion - First detection of ethylene glycol in Orion-KL

Comparison of their chemical compositions shows, to first order, a good agreement between the cometary and interstellar abundances. However, a complex O-bearing organic molecule, ethylene glycol (CH$_{2}$OH)$_{2}$, seems to depart from this correlation because it was not easily detected in the interstellar medium although it proved to be rather abundant with respect to other O-bearing species in comet Hale-Bopp. Ethylene glycol thus appears, together with the related molecules glycolaldehyde CH$_{2}$OHCHO and ethanol CH$_{3}$CH$_{2}$OH, as a key species in the comparison of interstellar and cometary ices as well as in any discussion on the formation of cometary matter. We focus here on the analysis of ethylene glycol in the nearest and best studied hot core-like region, Orion-KL. We use ALMA interferometric data because high spatial resolution observations allow us to reduce the line confusion problem with respect to single-dish observations since different molecules are expected to exhibit different spatial distributions. Furthermore, a large spectral bandwidth is needed because many individual transitions are required to securely detect large organic molecules. Confusion and continuum subtraction are major issues and have been handled with care. We have detected the aGg' conformer of ethylene glycol in Orion-KL. The emission is compact and peaks towards the Hot Core close to the main continuum peak, about 2" to the south-west; this distribution is notably different from other O-bearing species. Assuming optically thin lines and local thermodynamic equilibrium, we derive a rotational temperature of 145 K and a column density of 4.6 10$^{15}$ cm$^{-2}$. The limit on the column density of the gGg' conformer is five times lower.Comment: 19 pages, 10 figures, A&A accepte

HCOOCH3 as a probe of temperature and structure of Orion-KL

We studied the O-bearing molecule HCOOCH3 to characterize the physical conditions of the different molecular source components in Orion-KL. We identify 28 methyl formate emission peaks throughout the 50" field of observations. The two strongest peaks are in the Compact Ridge (MF1) and in the SouthWest of the Hot Core (MF2). Spectral confusion is still prevailing as half of the expected transitions are blended over the region. Assuming that the transitions are thermalized, we derive the temperature at the five main emission peaks. At the MF1 position we find a temperature of 80K in a 1.8"x0.8" beam size and 120K on a larger scale (3.6" x2.2"), suggesting an external source of heating, whereas the temperature is about 130K at the MF2 position on both scales. Transitions of HCOOCH3 in vt=1 are detected as well and the good agreement of the positions on the rotational diagrams between the vt=0 and the vt=1 transitions suggests a similar temperature. The velocity of the gas is between 7.5 and 8.0km/s depending on the positions and column density peaks vary from 1.6x10^16 to 1.6x10^17cm^-2. A second velocity component is observed around 9-10 km/s in a North-South structure stretching from the Compact Ridge up to the BN object; this component is warmer at the MF1 peak. The two other C2H4O2 isomers are not detected and the derived upper limit for the column density is <3x10^14cm^-2 for glycolaldehyde and <2x10^15cm^-2 for acetic acid. From the 223GHz continuum map, we identify several dust clumps with associated gas masses in the range 0.8 to 5.8Msun. Assuming that the HCOOCH3 is spatially distributed as the dust, we find relative abundances of HCOOCH3 in the range <0.1x10^-8 to 5.2x10^-8. We suggest a relation between the methyl formate distribution and shocks as traced by 2.12 mum H2 emission.Comment: Accepted for publication in A&

Extended Star Formation and Molecular Gas in the Tidal Arms near NGC3077

We report the detection of ongoing star formation in the prominent tidal arms near NGC 3077 (member of the M 81 triplet). In total, 36 faint compact HII regions were identified, covering an area of ~4x6 kpc^2. Most of the HII regions are found at HI column densities above 1x10^21 cm^-2 (on scales of 200 pc), well within the range of threshold columns measured in normal galaxies. The HII luminosity function resembles the ones derived for other low-mass dwarf galaxies in the same group; we derive a total star formation rate of 2.6x10^-3 M_sun/yr in the tidal feature. We also present new high-resolution imaging of the molecular gas distribution in the tidal arm using CO observations obtained with the OVRO interferometer. We recover about one sixth of the CO flux (or M_H2~2x10^6 M_sun, assuming a Galactic conversion factor) originally detected in the IRAM 30m single dish observations, indicating the presence of a diffuse molecular gas component in the tidal arm. The brightest CO peak in the interferometer map (comprising half of the detected CO flux) is coincident with one of the brightest HII regions in the feature. Assuming a constant star formation rate since the creation of the tidal feature (presumably ~3x10^8 years ago), a total mass of ~7x10^5 M_sun has been transformed from gas into stars. Over this period, the star formation in the tidal arm has resulted in an additional enrichment of Delta(Z)>0.002. The reservoir of atomic and molecular gas in the tidal arm is ~3x10^8 M_sun, allowing star formation to continue at its present rate for a Hubble time. Such wide-spread, low-level star formation would be difficult to image around more distant galaxies but may be detectable through intervening absorption in quasar spectra.Comment: Accepted for publication in the Astronomical Journa

Relations between cognition and motricity in children with neonatal arterial ischemic stroke

Introduction and goalPerinatal arterial ischemic stroke (PAIS) affects one child for 4000 births. The few studies about cognitive development specific to PAIS showed that cognitive performances in this population do not follow up a normal development (Westmacott et al., 2010; Ricci et al., 2008). Based on new data about relation between motricity and cognition (Smits-Engelsman et Hill, 2012), and on the theory of the embodied cognition, led us to hypothesize that cognitive performances would be correlated to the motor performances in children with PAIS.Patients and methodologyWe tested 77 7 years old children meeting the criteria of neonatal AIS, with a diagnosis before the 28th day of life relying on cerebral imagery. After excluding children with seizure and bi-hemispheric lesion, 56 children participated to our study. The cognitive evaluation was performed with the Wechsler Intelligence Scale for Children (WISC-4), the motor evaluation relied on testing of gross motor of the upper arm (Box and Block Test) and fine prehension test (“Nine Hole Peg Test”). The localisation of the lesion, the economic level of parents, the gender, sensory impairments and the presence of hemiplegia were collected. We analyzed these results with simple linear regression.ResultsThe main result of our study is the significative correlation (P<0.03) between scores of the WISC4 (except for working memory index) and motor results. In contrast we did not find any correlation between the scores of the WISC4 and the presence of hemiplegia or with lesion localization.DiscussionMany brain networks develop during the first year through sensorimotor experiences, which contribute to the emergence of knowledge. This concept of development, supported by the approach embodied cognition, can explain the correlations between cognition and motor found in our work and in several studies with children with other early neurological damage

Gemini Spectroscopy and HST Imaging of the Stellar Cluster Population in Region B of M82

We present new spectroscopic observations of the stellar cluster population of region B in the prototype starburst galaxy M82 obtained with the Gillett Gemini-North 8.1-metre telescope. By coupling the spectroscopy with UBVI photometry acquired with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), we derive ages, extinctions and radial velocities for seven young massive clusters (YMCs) in region B. We find the clusters to have ages between 70 and 200 Myr and velocities in the range 230 to 350 km/s, while extinctions Av vary between ~1-2.5 mag. We also find evidence of differential extinction across the faces of some clusters which hinders the photometric determination of ages and extinctions in these cases. The cluster radial velocities indicate that the clusters are located at different depths within the disk, and are on regular disk orbits. Our results overall contradict the findings of previous studies, where region B was thought to be a bound region populated by intermediate-age clusters that formed in an independent, offset starburst episode that commenced 600 Myr-1 Gyr ago. Our findings instead suggest that region B is optically bright because of low extinction patches, and this allows us to view the cluster population of the inner M82 disk, which probably formed as a result of the last encounter with M81. This study forms part of a series of papers aimed at studying the cluster population of M82 using deep optical spectroscopy and multi-band photometry.Comment: 12 pages, 8 figures; accepted for publication in The Astrophysical Journa

Molecular clouds in the center of M81

We investigate the molecular gas content and the excitation and fragmentation properties in the central region of the spiral galaxy Messier 81 in both the ^{12}CO(1-0) and ^{12}CO(2-1) transitions. We have recently observed the two transitions of CO in the M~81 center with A, B, and HERA receivers of the IRAM 30-m telescope. We find no CO emission in the inner $\sim$ 300 pc and a weak molecular gas clump structure at a distance of around 460 pc from the nucleus. Observations of the first two CO transitions allowed us to compute the line ratio, and the average I_{21}/I_{10} ratio is 0.68 for the M~81 center. This low value, atypical both of the galactic nuclei of spiral galaxies and of interacting systems, is probably associated to diffuse gas with molecular hydrogen density that is not high enough to excite the CO molecules. After analyzing the clumping properties of the molecular gas in detail, we identify very massive giant molecular associations (GMAs) in CO(2-1) emission with masses of $\sim$ 10$^{5}$ M$_\odot$ and diameters of $\sim$ 250 pc. The deduced N(H_{2})/I_{CO} ratio for the individually resolved GMAs, assumed to be virialized, is a factor of $\sim$ 15 higher than the \textit{standard} Galactic value, showing - as suspected - that the X ratio departs significantly from the mean for galaxies with an unusual physics of the molecular gas.Comment: 12 pages, 7 figures, 6 tables. Accepted for pubblication in A&

The Discovery of a Molecular Complex in the Tidal Arms near NGC 3077

We present the discovery of a giant molecular complex (r=350 pc, M_ vir=10^7 M_sun) in the tidal arms south-east of NGC 3077, a member of the M 81 triplet. The complex is clearly detected in the 12CO (J=1-0) transition at five independent positions. The position relative to NGC 3077, the systemic velocity (v_hel=14km/s) and the cloud averaged line width (15km/s) indicate that the object is not related to Galactic cirrus but is extragalactic. The tidal HI arm where the molecular complex is located has an total HI mass of M_HI=3x10^8 M_sun. This tidal material was presumably stripped off the outer parts of NGC 3077 during the closest encounter with M 81, about 3x10^8 years ago. After the complex detected along a torn-out spiral arm of M 81 by Brouillet et al., it is the second of its kind reported so far. Based on published optical observations, we have no evidence for on--going star formation in the newly detected molecular complex. Since the system has all the ingredients to form stars in the future, we speculate that it might eventually resemble the young dwarf galaxies in the M 81 group.Comment: 12 pages (including 3 figures), accepted for publication in the ApJ Letter

Exposing elusive cationic magnesium-chloro aggregates in aluminate complexes through donor control

The cationic magnesium moiety of magnesium organohalo aluminate complexes, relevant to rechargeable Mg battery electrolytes, typically takes the thermodynamically favourable dinuclear [Mg2Cl3]+ form in the solid-state. We now report that judicious choice of Lewis donor allows the deliberate synthesis and isolation of the hitherto only postulated mononuclear [MgCl]+ and trinuclear [Mg3Cl5]+ modifications, forming a comparable series with a common aluminate anion [(Dipp)(Me3Si)NAlCl3]. By pre-forming the Al-N bond prior to introduction of the Mg source, a consistently reproducible protocol is reported. Usage of the green solvent 2-methyltetrahydrofuran in place of THF in the context of Mg/Al battery electrolyte type complexes is also promoted

Tracing high density gas in M 82 and NGC 4038

We present the first detection of CS in the Antennae galaxies towards the NGC 4038 nucleus, as well as the first detections of two high-J (5-4 and 7-6) CS lines in the center of M 82. The CS(7-6) line in M 82 shows a profile that is surprisingly different to those of other low-J CS transitions we observed. This implies the presence of a separate, denser and warmer molecular gas component. The derived physical properties and the likely location of the CS(7-6) emission suggests an association with the supershell in the centre of M 82.Comment: 10 pages, 3 figures, ApJ Letter - ACCEPTE

Dense Molecular Gas Associated with the Circumnuclear Star Forming Ring in the Barred Spiral Galaxy NGC 6951

We present high resolution (3" - 5") observations of CO(1-0) and HCN(1-0) emission from the circumnuclear star forming ring in the barred spiral galaxy NGC 6951, a host of a type-2 Seyfert, using the Nobeyama Millimeter Array and 45 m telescope. We find that most of the HCN emission is associated with the circumnuclear ring, where vigorous star formation occurs. The HCN to CO integrated intensity ratio is also enhanced in the star forming ring; the peak value of HCN/CO ratio is 0.18, which is comparable to the ratio in the starbursts NGC 253 and M82. The formation mechanism of dense molecular gas has been investigated. We find that the shocks along the orbit crowding do not promote the formation of the dense molecular gas effectively but enhance the presence of low density GMCs. Instead, gravitational instabilities of the gas can account for the dense molecular gas formation. The HCN/CO ratio toward the Seyfert nucleus of NGC 6951 is a rather normal value (0.086), in contrast with other Seyferts NGC 1068 and M51 where extremely high HCN/CO value of ~ 0.5 have been reported.Comment: 33 pages, 17 figures, to appear in the Astrophysical Journa