BAORadio : Cartographie 3D de la distribution de gaz HI_I dans l'Univers

3D mapping of matter distribution in the universe through the 21 cm radio emission of atomic hydrogen is a complementary approach to optical surveys for the study of the Large Scale Structures, in particular for measuring the BAO (Baryon Acoustic Oscillation) scale up to redshifts z <~ 3 and constrain dark energy. We propose to carry such a survey through a novel method, called intensity mapping, without detecting individual galaxies radio emission. This method requires a wide band instrument, 100 MHz or larger, and multiple beams, while a rather modest angular resolution of 10 arcmin would be sufficient. The instrument would have a few thousand square meters of collecting area and few hundreds of simultaneous beams. These constraints could be fulfilled with a dense array of receivers in interferometric mode, or a phased array at the focal plane of a large antenna

Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide

A spectral survey in the 1 mm wavelength range was undertaken in the long-period comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy) using the 30 m telescope of the Institut de radioastronomie millim\'etrique (IRAM) in April and November-December 2013. We report the detection of ethylene glycol (CH$_2$OH)$_2$ (aGg' conformer) and formamide (NH$_2$CHO) in the two comets. The abundances relative to water of ethylene glycol and formamide are 0.2-0.3% and 0.02% in the two comets, similar to the values measured in comet C/1995 O1 (Hale-Bopp). We also report the detection of HCOOH and CH$_3$CHO in comet C/2013 R1 (Lovejoy), and a search for other complex species (methyl formate, glycolaldehyde).Comment: Accepted for publication as a Letter in Astronomy and Astrophysic

Ethylene glycol in comet C/1995 O1 (Hale-Bopp)

We report the detection of ethylene glycol (HOCH_2CH_2OH) in comet C/1995 O1 (Hale-Bopp) from the analysis of archival radio spectra. Its production rate is ≈0.25% that of water, making it one of the most abundant organic molecules in cometary ices. This detection strengthens the similarity between interstellar and cometary material

Modelling the influence of RKIP on the ERK signalling pathway using the stochastic process algebra PEPA

This paper examines the influence of the Raf Kinase Inhibitor Protein (RKIP) on the Extracellular signal Regulated Kinase (ERK) signalling pathway [5] through modelling in a Markovian process algebra, PEPA [11]. Two models of the system are presented, a reagent-centric view and a pathway-centric view. The models capture functionality at the level of subpathway, rather than at a molecular level. Each model affords a different perspective of the pathway and analysis. We demonstrate the two models to be formally equivalent using the timing-aware bisimulation defined over PEPA models and discuss the biological significance

The composition of ices in comet C/1995 O1 (Hale-Bopp) from radio spectroscopy - Further results and upper limits on undetected species

From radio spectroscopic observations of comets, more than 22 molecules, radicals and ions, plus several isotopologues, were detected, the majority of them being recently revealed in comets C/1996 B2 (Hyakutake) and C/1995 O1 (Hale-Bopp). Among them, 6 molecules were detected for the first time (Bockelée-Morvan et al. [CITE]) in the course of a spectral survey conducted at radio wavelengths in comet Hale-Bopp with the CSO, the IRAM 30-m telescope and Plateau de Bure interferometer. In addition, many species were searched for unsuccessfully, some of them with stringent upper limits. We present here a review of these observations and further analysis of their results. This include: (i) confirmed detection of acetaldehyde (CH_3CHO); (ii) limits on small molecules such as ketene (H_2CCO) or methanimine (CH_2NH); (iii) limits on the abundance ratios in homologous series such as HC_5N/HC_3N, ethanol/methanol, acetic acid/formic acid; (iv) searches for precursors of key cometary species such as atomic Na and HNC; (v) constraints on more exotic species ranging from water dimer (H_2O)_2 to glycine; (vi) detection of the H_2^(34)S isotopic species and independent observations of HDO and DCN; (vii) limits on several other deuterated species; (viii) limits on several radicals and ions and a tentative detection of the C_2H radical; (ix) the presence of unidentified lines. Typical abundance upper limits of 2–5 x 10^(-4) relative to water are achieved for many species. Better upper limits are obtained for some linear molecules with high dipole moments. But more complex molecules such as dimethyl ether or glycine are poorly constrained. These results should give important clues to the chemical composition of cometary ices, to the formation mechanisms of cometary material, and to the chemical processes which occur in the inner coma

Large excess of heavy nitrogen in both hydrogen cyanide and cyanogen from comet 17P/Holmes

From millimeter and optical observations of the Jupiter-family comet 17P/Holmes performed soon after its huge outburst of October 24, 2007, we derive 14 N/15N = 139 +/- 26 in HCN, and 14N/15N = 165 +/- 40 in CN, establishing that HCN has the same non-terrestrial isotopic composition as CN. The same conclusion is obtained for the long-period comet C/1995 O1 (Hale-Bopp) after a reanalysis of previously published measurements. These results are compatible with HCN being the prime parent of CN in cometary atmospheres. The 15N excess relative to the Earth atmospheric value indicates that N-bearing volatiles in the solar nebula underwent important N isotopic fractionation at some stage of Solar System formation. HCN molecules never isotopically equilibrated with the main nitrogen reservoir in the solar nebula before being incorporated in Oort-cloud and Kuiper-belt comets. The 12C/13C ratios in HCN and CN are measured to be consistent with the terrestrial value.Comment: Accepted for publication in the Astrophysical Journal (Letters) 4 page