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Spectroscopic Observations (spectroscopic + observation)
Kinds of Spectroscopic Observations Selected AbstractsInfrared Spectroscopic Observation of the Group 13 Metal Hydroxides, M(OH)1,2,3 (M: Al, Ga, In, and Tl) and HAl(OH2)CHEMINFORM, Issue 22 2007Xuefeng Wang Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] First Isolation and Spectroscopic Observation of Thiofulminic acid (HCNS)CHEMISTRY - A EUROPEAN JOURNAL, Issue 25 2009Tibor Pasinszki Prof. Abstract For the first time: Thiofulminic acid (HCNS), the parent member of the nitrile sulfide family of reactive intermediates and potential interstellar species, was produced and characterized by IR spectroscopy for the first time. HCNS was generated in cryogenic matrices by 254,nm UV irradiation of 1,2,5-thiadiazole (see figure). [source] Mid-Infrared Imaging and Spectroscopic Observations of the Galactic Center with Subaru/COMICSASTRONOMISCHE NACHRICHTEN, Issue S1 2003Y. Okada Abstract We report the results of mid-infrared (7.8,m,13.2 ,m) high-spatial resolution imaging and spectroscopic observations of the Galactic center region with the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru telescope. The images clearly show bright infrared sources and small structures in the diffuse emission. The spectra of all the observed positions show the 9.7 ,m silicate absorption feature. After corrected for the empirically-derived extinction, the intrinsic spectra of the infrared sources show either strong silicate emission or absorption, while the intrinsic diffuse emission has a power-law type spectrum. This difference indicates a possibility of dust processing due to the interaction between the infrared sources and their surrounding medium or a different origin of the dust grains surrounding the sources from those in the diffuse region. [source] Microscopic and Spectroscopic Observations in the Bio-Nanoworld,CHEMPHYSCHEM, Issue 9-10 2009Peter Hinterdorfer Prof. Abstract Biophysics in Linz: In February biophysicists from across the world converged on Linz for two biophysical conferences. The city which is the Cultural Capital of Europe 2009, provided the perfect environment for fruitful discussions on single-molecule techniques in biophysics, bio-nanotechnology, cell biology, and drug discovery. [source] Optical spectroscopy of GX 339,4 during the high,soft and low,hard states , II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2001Line ionization, emission region We have carried out observations of the X-ray transient GX 339,4 during its high,soft and low,hard X-ray spectral states. Our high-resolution spectroscopic observation in 1999 April suggests that the H, line has a single-peaked profile in the low,hard state as speculated in our previous paper. The He ii,4686 line, however, has a double-peaked profile in both the high,soft and low,hard states. This suggests that the line-emission mechanism is different in the two states. Our interpretation is that double-peaked lines are emitted from a temperature-inversion layer on the accretion disc surface when it is irradiatively heated by soft X-rays. Single-peaked lines may be emitted from outflow/wind matter driven by hard X-ray heating. We have constructed a simple plane-parallel model and we use it to illustrate that a temperature-inversion layer can be formed at the disc surface under X-ray illumination. We also discuss the conditions required for the formation of temperature inversion and line emission. Based on the velocity separations measured for the double-peaked lines in the high,soft state, we propose that GX 339,4 is a low-inclination binary system. The orbital inclination is about 15° if the orbital period is 14.8 h. [source] Sulfur Dioxide and Water: Structures and Energies of the Hydrated Species SO2·nH2O, [HSO3],·nH2O, [SO3H],·nH2O, and H2SO3·nH2O (n = 0,8)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2009Ralf Steudel Abstract The structures of a large number of hydrates of sulfur dioxide (SO2·nH2O), of the sulfonate ion ([HSO3],·nH2O), of the tautomeric hydrogensulfite anion ([SO3H],·nH2O), and of sulfurous acid (H2SO3·nH2O) with up to eight water molecules attached to these species have been optimized at the B3LYP/6-31G(2df,p) level of theory (DFT). The calculated vibrational frequencies allow the definite assignment of certain characteristic modes, and in this way a convincing interpretation of published spectra of aqueous SO2 as well as of SO2 adsorbed on very cold ice crystals has been achieved for the first time. Single-point calculations at the G3X(MP2) level of theory were used to calculate the binding energies of the water molecules in SO2·nH2O as well as the relative stabilities of the isomeric anionic species [HSO3],·nH2O and [SO3H],·nH2O. Generally, the water molecules tend to stick together forming clusters, whereas the particular sulfur-containing molecule remains at the surface of the water cluster, but it is always strongly hydrogen-bonded. Only when there are more than six water molecules are the anions more or less completely surrounded by water molecules. DFT calculations erroneously predict that the gaseous hydrated sulfonate ions are more stable than the isomeric hydrogensulfite ions, even when hydrated with six water molecules. However, if these hydrated species are calculated as being embedded in a polar continuum simulating the aqueous phase, the hydrogensulfite ions are more stable than the sulfonate ions, in agreement with various spectroscopic observations on aqueous sulfite solutions. On the other hand, at the higher G3X(MP2) level, the gaseous hydrated hydrogensulfite anions are more stable than the corresponding sulfonate ions only if the number of water molecules is larger than four, whereas for the weakly hydrated anions the order of relative energies is reversed. The possible implications of these results for the enzymatic oxidation of "sulfite ions" ([HSO3], and [SO3H],) by sulfite oxidase are discussed. The conversion of SO2·6H2O into its isomer H2SO3·5H2O is predicted to be exothermic (,H°298 = ,56.1 kJ,mol,1) and exergonic (,G°298 = ,22.5 kJ,mol,1). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Rotational velocities of the giants in symbiotic stars , III.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2008Evidence of fast rotation in S-type symbiotics ABSTRACT We have measured the projected rotational velocities (v sin i) in a number of symbiotic stars and M giants using high-resolution spectroscopic observations. On the basis of our measurements and data from the literature, we compare the rotation of mass donors in symbiotics with v sin i of field giants and find that: (i) the K giants in S-type symbiotics rotate at v sin i > 4.5 km s,1, which is 2,4 times faster than the field K giants; (ii) the M giants in S-type symbiotics rotate on average 1.5 times faster than the field M giants. Statistical tests show that these differences are highly significant , p-value <10,3 in the spectral-type bins K2III-K5III, M0III-M6III and M2III-M5III and (iii) our new observations of D'-type symbiotics also confirm that they are fast rotators. As a result of the rapid rotation, the cool giants in symbiotics should have 3,30 times larger mass-loss rates. Our results suggest also that bipolar ejections in symbiotics seem to happen in objects where the mass donors rotate faster than the orbital period. All spectra used in our series of papers can be obtained upon request from the authors. [source] Multiwavelength study of the nuclei of a volume-limited sample of galaxies , II.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Optical, infrared, radio observations ABSTRACT We present optical and infrared broad-band images, radio maps, and optical spectroscopy for the nuclear region of a sample of nearby galaxies. The galaxies have been drawn from a complete volume-limited sample for which we have already presented X-ray imaging. We modelled the stellar component of the spectroscopic observations to determine the star formation history of our targets. Diagnostic diagrams were used to classify the emission-line spectra and determine the ionizing mechanism driving the nuclear regions. All those sources classified as active galactic nuclei present small Eddington ratios (,10,3,10,6), implying a very slow growth rate of their black holes. We finally investigate the relative numbers of active and normal nuclei as a function of host galaxy luminosity and find that the fraction of active galaxies slowly rises as a function of host absolute magnitude in the MB,,12 to ,22 range. [source] The polar ring galaxy AM1934,563 revisited,MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007Noah Brosch ABSTRACT We report long-slit spectroscopic observations of the dust-lane polar ring galaxy AM1934,563 obtained with the Southern African Large Telescope (SALT) during its performance verification phase. The observations target the spectral region of the H,, [N ii] and [S ii] emission lines, but also show deep Na i absorption lines, that we interpret as being produced by stars in the galaxy. We derive rotation curves along the major axis of the galaxy that extend out to about 8 kpc from the centre for both the gaseous and the stellar components, using the emission and absorption lines. We derive similar rotation curves along the major axis of the polar ring and point out differences between these and the ones of the main galaxy. We identify a small diffuse object visible only in H, emission and with a low velocity dispersion as a dwarf H ii galaxy and argue that it is probably metal poor. Its velocity indicates that it is a fourth member of the galaxy group in which AM1934,563 belongs. We discuss the observations in the context of the proposal that the object is the result of tidal mater transfer from a major neighbour galaxy and point out some observational discrepancies from this explanation. We argue that an alternative scenario that could better fit the observations may be the slow accretion of cold intergalactic gas, focused by a dense filament of galaxies in which this object is embedded. Given the pattern of rotation we found, with the asymptotic rotation of the gas in the ring being slower than that in the disc while both components have approximately the same extent, we point out that AM1934,563 may be a galaxy in which a dark matter halo is flattened along the galactic disc and the first object in which this predicted behaviour of polar ring galaxies in dark matter haloes is fulfilled. [source] Gemini near-infrared integral field spectroscopy of the narrow-line region of ESO 428,G14: kinematics, excitation and the role of the radio jetMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2006Rogemar A. Riffel ABSTRACT We present two-dimensional (2D) gas kinematics and excitation of the inner 300 pc of the Seyfert galaxy ESO 428,G14 at a sampling of 14 pc2, from near-infrared spectroscopic observations at R, 6000 obtained with the Integral Field Unit (IFU) of the Gemini Near-Infrared Spectrograph. From measurements of fluxes and profiles of the emission lines [Fe ii],1.257 ,m, Pa,, H2, 2.121 ,m and Br,, we construct 2D maps of line intensities and ratios, radial velocities and velocity dispersions. Emission line ,tomography' is provided by velocity slices obtained across the line profiles, a unique capability of IFUs, which allows the mapping of not only the peak velocities but including also the wings. We compare these maps with a previously published high spatial resolution radio map and find a tight relation between the radio structure and the emission-line flux distributions and kinematics, revealing that the radio jet plays a fundamental role not only in shaping the narrow-line region but also in the imprint of its kinematics. Blueshifts of up to 400 km s,1 and velocity dispersions of up to 150 km s,1 are observed in association with the radio jet at a position angle (PA) = 129°, which is also the PA of the photometric major axis of the galaxy. We conclude that the radio jet is launched at a small angle relative to the galactic plane, with the north-western side slightly oriented towards us. This angle is small enough for the radio jet to shock and compress the gas in the plane of the galaxy, and for the nuclear continuum to ionize and heat it. The distinct kinematics and flux distributions observed for the different emission lines suggest different origins for their emission. The [Fe ii] shows the largest blueshifts and velocity dispersions and its flux distribution is concentrated along the jet, while the H2 shows the lowest velocity dispersions and has additional flux contribution from regions beyond the jet. Both X-rays emitted by the active galactic nucleus and shocks produced by the radio jet can excite the H2 and [Fe ii] emission lines. We use the 2D velocity dispersion maps to estimate upper limits to the contribution of the radio jet to the excitation of [Fe ii] and H2 which may reach 90 per cent for [Fe ii] and 80 per cent for H2 in the jet region. The [Fe ii]/Pa, emission-line ratios and the association of the [Fe ii] flux distribution and kinematics with the radio structure support a stronger contribution of the radio jet to the [Fe ii] excitation than that of H2. In the regions beyond the jet, the observations favour X-ray excitation. [source] Stellar haloes and elliptical galaxy formation: origin of dynamical properties of the planetary nebula systemsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2006Kenji Bekki ABSTRACT Recent spectroscopic observations of planetary nebulae (PNe) in several elliptical galaxies have revealed structural and kinematical properties of the outer stellar halo regions. In order to elucidate the origin of the properties of these planetary nebula systems (PNSs), we consider the merger scenario in which an elliptical galaxy is formed by merging of spiral galaxies. Using numerical simulations, we particularly investigate radial profiles of projected PN number densities, rotational velocities and velocity dispersions of PNSs extending to the outer halo regions of elliptical galaxies formed from major and unequal-mass merging. We find that the radial profiles of the project number densities can be fitted to the power law and the mean number density in the outer haloes of the ellipticals can be more than an order of magnitude higher than that of the original spiral's halo. The PNSs are found to show a significant amount of rotation (V/, > 0.5) in the outer halo regions (R > 5Re) of the ellipticals. Two-dimensional velocity fields of PNSs are derived from the simulations and their dependences on model parameters of galaxy merging are discussed in detail. We compare the simulated kinematics of PNSs with that of the PNS observed in NGC 5128 and thereby discuss advantages and disadvantages of the merger model in explaining the observed kinematics of the PNS. We also find that the kinematics of PNSs in elliptical galaxies are quite diverse depending on the orbital configurations of galaxy merging, the mass ratio of merger progenitor spirals and the viewing angle of the galaxies. This variation translates directly into possible biases by a factor of 2 in observational mass estimation. However, the biases in the total mass estimates can be even larger. The best case systems viewed edge-on can appear to have masses lower than their true mass by a factor of 5, which suggests that current observational studies on PN kinematics of elliptical galaxies can significantly underestimate their real masses. [source] New photometric and spectroscopic observations of the Seyfert galaxy Mrk 315MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2005S. Ciroi ABSTRACT We present new important results about the intermediate-type Seyfert galaxy Mrk 315, recently observed through optical imaging and integral-field spectroscopy. Broad-band images were used to study the morphology of the host galaxy, narrow-band H, images to trace the star-forming regions, and middle-band [O iii] images to evidence the distribution of the highly ionized gas. Some extended emission regions were isolated and their physical properties studied by means of flux-calibrated spectra. High-resolution spectroscopy was used to separate different kinematic components in the velocity fields of gas and stars. Some peculiar features characterize this apparently undisturbed and moderately isolated active galaxy. Such features, already investigated by other authors, are re-analysed and discussed in the light of these new observations. The most relevant results we obtained are: the multitiers structure of the disc; the presence of a quasi-ring of regions with star formation much higher than previous claims; a secondary nucleus confirmed by a stellar component kinematically decoupled by the main galaxy; a new hypothesis about the controversial nature of the long filament, initially described as hook shaped, and more likely made of two independent filaments caused by interaction events between the main galaxy and two dwarf companions. [source] Near-infrared identification of the counterpart to X1908+075: a new OB-supergiant X-ray binaryMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2005T. Morel ABSTRACT We report the near-infrared (near-IR) identification of the likely counterpart to X1908+075, a highly absorbed Galactic X-ray source recently suspected to belong to the rare class of OB supergiant,neutron star binary systems. Our JHKs -band imaging of the field reveals the existence within the X-ray error boxes of a near-IR source consistent with an early-type star lying at d, 7 kpc and suffering AV, 16 mag of extinction, the latter value being in good agreement with the hydrogen column density derived from modelling of the X-ray spectrum. Our follow-up, near-IR spectroscopic observations confirm the nature of this candidate and lead to a late O-type supergiant classification, thereby supporting the identification of a new Galactic OB-supergiant X-ray binary. [source] Eclipsing binaries in open clusters , III.MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2004Persei, V621 Per in ABSTRACT V621 Persei is a detached eclipsing binary in the open cluster , Persei, which is composed of an early B-type giant star and a main-sequence secondary component. From high-resolution spectroscopic observations and radial velocities from the literature, we determine the orbital period to be 25.5 d and the primary velocity semi-amplitude to be K= 64.5 ± 0.4 km s,1. No trace of the secondary star has been found in the spectrum. We solve the discovery light curves of this totally eclipsing binary and find that the surface gravity of the secondary star is log gB= 4.244 ± 0.054. We compare the absolute masses and radii of the two stars in the mass,radius diagram, for different possible values of the primary surface gravity, with the predictions of stellar models. We find that log gA, 3.55, in agreement with values found from fitting Balmer lines with synthetic profiles. The expected masses of the two stars are 12 and 6 M, and the expected radii are 10 and 3 R,. The primary component is near the blue loop stage in its evolution. [source] Evolution of the 3.3-,m emission feature in the Red RectangleMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2003In-Ok Song ABSTRACT Medium-resolution infrared spectroscopic observations of the biconical Red Rectangle nebula in the region of the 3.3-,m unidentified infrared (UIR) emission band are reported. The data were recorded at UKIRT using CGS4 and have allowed the peak wavelength, width, profile and intensity of the 3.3-,m feature to be investigated as a function of offset from the central star HD 44179. Analysis of the profile of the feature along the north-western bicone interface shows an evolution from Type 2 to Type 1 in the classification of Tokunaga et al. The 3.3-,m band recorded on-star shows a close fit to a Lorentzian profile, possibly suggesting a single class of carriers. Subtraction of the Lorentzian fit to the on-star spectrum from the spectrum at each offset reveals a new ,3.28'-,m emission feature that grows in intensity relative to the main 3.3-,m band as a function of distance from the central star. The 3.28-,m emission band at large offset appears to correspond well in wavelength and FWHM with an absorption feature seen towards the Galactic Centre. [source] Optical gravitational lensing experiment: OGLE-1999-BUL-19 , the first multipeak parallax eventMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2002Martin C. Smith Abstract We describe a highly unusual microlensing event, OGLE-1999-BUL-19. Unlike most standard microlensing events, this event exhibits multiple peaks in its light curve. The Einstein radius crossing time for this event is approximately 1 yr, which is unusually long. We show that the additional peaks in the light curve can be caused by the very small value for the relative transverse velocity of the lens projected on to the observer plane (). Since this value is significantly less than the speed of the orbit of the Earth around the Sun (v,, 30km s,1), the motion of the Earth induces these multiple peaks in the light curve. This value for is the lowest velocity so far published and we believe that this is the first multiple-peak parallax event ever observed. We also found that the event can be somewhat better fitted by a rotating binary-source model, although this is to be expected since every parallax microlensing event can be exactly reproduced by a suitable binary-source model. A face-on rotating binary-lens model was also identified, but this provides a significantly worse fit. We conclude that the most likely cause for this multipeak behaviour is parallax microlensing rather than microlensing by a binary source. However, this event may be exhibiting a slight binary-source signature in addition to these parallax-induced multiple peaks. With spectroscopic observations it is possible to test this ,parallax plus binary-source' hypothesis and (in the instance that the hypothesis turns out to be correct) to simultaneously fit both models and obtain a measurement of the lens mass. Furthermore, spectroscopic observations could also supply information regarding the lens properties, possibly providing another avenue for determining the lens mass. We also investigated the nature of the blending for this event, and found that the majority of the I -band blending is contributed by a source roughly aligned with the lensed source. This implies that most of the I -band blending is caused by light from the lens or a binary companion to the source. However, in the V band, there appears to be a second blended source 0.35 arcsec away from the lensed source. Hubble Space Telescope observations will be very useful for understanding the nature of the blends. We also suggest that a radial velocity survey of all parallax events will be very useful for further constraining the lensing kinematics and understanding the origins of these events and the excess of long events toward the bulge. [source] Emission-line outflows in PKS1549,79: the effects of the early stages of radio-source evolution?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001C. Tadhunter We present new spectroscopic observations of the southern radio galaxy . Despite the flat-spectrum character of the radio emission from this source, our optical spectra show no sign of the broad permitted lines and non-stellar continuum characteristic of quasar nuclei and broad-line radio galaxies. However, the high-ionization forbidden lines, including [O iii],,5007, 4959, are unusually broad for a narrow-line radio galaxy , and are blueshifted by 600 km s,1 relative to the low-ionization lines such as [O ii],,3726,3729. The [O ii] lines are also considerably narrower than the [O iii] lines, and have a redshift consistent with that of the recently detected H i 21-cm absorption-line system. Whereas the kinematics of the [O iii] emission lines are consistent with outflow in an inner narrow-line region, the properties of the [O ii] emission lines suggest that they are emitted by a more extended and quiescent gaseous component. We argue that, given the radio properties of the source, our line of sight is likely to be lying close to the direction of bulk outflow of the radio jets. In this case it is probable that the quasar nucleus is entirely obscured at optical wavelengths by the material responsible for the H i absorption-line system. The unusually broad [O iii] emission lines suggest that the radio source is intrinsically compact. Overall, our data are consistent the idea that is a radio source in an early stage of evolution. [source] Constraining the star formation histories of spiral bulgesMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2000R. N. Proctor Stellar populations in spiral bulges are investigated using the Lick system of spectral indices. Long-slit spectroscopic observations of line strengths and kinematics made along the minor axes of four spiral bulges are reported. Comparisons are made between central line strengths in spiral bulges and those in other morphological types [elliptical, spheroidal (Sph) and S0]. The bulges investigated are found to have central line strengths comparable to those of single stellar populations of approximately solar abundance or above. Negative radial gradients are observed in line strengths, similar to those exhibited by elliptical galaxies. The bulge data are also consistent with correlations between Mg2, Mg2 gradient and central velocity dispersion observed in elliptical galaxies. In contrast to elliptical galaxies, central line strengths lie within the loci defining the range of ,Fe, and Mg2 achieved by Worthey's solar abundance ratio, single stellar populations (SSPs). The implication of solar abundance ratios indicates significant differences in the star formation histories of spiral bulges and elliptical galaxies. A ,single zone with infall' model of galactic chemical evolution, using Worthey's SSPs, is used to constrain the possible star formation histories of our sample. We show that the ,Fe,, Mg2 and H, line strengths observed in these bulges cannot be reproduced using primordial collapse models of formation but can be reproduced by models with extended infall of gas and star formation (2,17 Gyr) in the region modelled. One galaxy (NGC 5689) shows a central population with a luminosity-weighted average age of ,5 Gyr, supporting the idea of extended star formation. Kinematic substructure, possibly associated with a central spike in metallicity, is observed at the centre of the Sa galaxy NGC 3623. [source] Photometric and spectroscopic observations of three rapidly rotating late-type stars: EY Dra, V374 Peg, and GSC 02038-00293,ASTRONOMISCHE NACHRICHTEN, Issue 8 2010H. Korhonen Abstract Here, BV (RI)C broad band photometry and intermediate resolution spectroscopy in H, region are presented for two rapidly rotating late-type stars: EY Dra and V374 Peg. For a third rapid rotator, GSC 02038-00293, intermediate resolution H, spectroscopy and low resolution spectroscopy are used for spectral classification and stellar parameter investigation of this poorly known object. The low resolution spectrum of GSC 02038-00293 clearly indicates that it is a K-type star. Its intermediate resolution spectrum can be best fitted with a model with Teff = 4750 K and v sin i = 90 km s,1, indicating a very rapidly rotating mid-K star. The H, line strength is variable, indicating changing chromospheric emission on GSC 02038-00293. In the case of EY Dra and V374 Peg, the stellar activity in the photosphere is investigated from the photometric observations, and in the chromosphere from the H, line. The enhanced chromospheric emission in EY Dra correlates well with the location of the photospheric active regions, indicating that these features are spatially collocated. Hints of this behaviour are also seen in V374 Peg, but it cannot be confirmed from the current data. The photospheric activity patterns in EY Dra are stable during one observing run lasting several nights, whereas in V374 Peg large night-tonight variations are seen. Two large flares, one in the H, observations and one from the broadband photometry, and twelve smaller ones were detected in V374 Peg during the observations spanning nine nights. The energy of the photometrically detected largest flare is estimated to be 4.25 × 1031, 4.3 × 1032 erg, depending on the waveband. Comparing the activity patterns in these two stars, which are just below and above the mass limit of full convection, is crucial for understanding dynamo operation in stars with different internal structures (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Orbital eccentricity of the symbiotic star MWC 560,ASTRONOMISCHE NACHRICHTEN, Issue 3 2010R.K. Zamanov Abstract We present projected rotational velocity measurements of the red giant in the symbiotic star MWC 560, using the high-resolution spectroscopic observations with the FEROS spectrograph. We find that the projected rotational velocity of the red giant is v sin i = 8.2 ± 1.5 km s,1, and estimate its rotational period tobe Prot = 144,306 days. Using the theoretical predictions of tidal interaction and pseudosynchronization, we estimate the orbital eccentricity e = 0.68,0.82. We briefly discuss the connection of our results with the photometric variability of the object (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The chromospherically active binary star EI Eridani: II.ASTRONOMISCHE NACHRICHTEN, Issue 4 2009Long-term Doppler imaging Abstract Data from 11 years of continuous spectroscopic observations of the active RS CVn-type binary star EI Eridani , gained at NSO/McMath-Pierce, KPNO/Coudé Feed and during the MUSICOS 98 campaign , were used to obtain 34 Doppler maps in three spectroscopic lines for 32 epochs, 28 of which are independent of each other. Various parameters are extracted from our Doppler maps: average temperature, fractional spottedness, and longitudinal and latitudinal spot-occurrence functions. We find that none of these parameters show a distinct variation nor a correlation with the proposed activity cycle as seen from photometric long-term observations. This suggests that the photometric brightness cycle may not necessarily be due to just a cool spot cycle. The general morphology of the spot pattern remains persistent over the whole period of 11 years. A large cap-like polar spot was recovered from all our images. A high degree of variable activity was noticed near latitudes of ,60,70° where the appendages of the polar spot emerged and dissolved (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Nearby stars of the Galactic disk and halo.ASTRONOMISCHE NACHRICHTEN, Issue 1 2004Abstract High-resolution spectroscopic observations of about 150 nearby stars or star systems are presented and discussed. The study of these and another 100 objects of the previous papers of this series implies that the Galaxy became reality 13 or 14 Gyr ago with the implementation of a massive, rotationally-supported population of thick-disk stars. The very high star formation rate in that phase gave rise to a rapid metal enrichment and an expulsion of gas in supernovae-driven Galactic winds, but was followed by a star formation gap for no less than three billion years at the Sun's galactocentric distance. In a second phase, then, the thin disk , our "familiar Milky Way" , came on stage. Nowadays it traces the bright side of the Galaxy, but it is also embedded in a huge coffin of dead thick-disk stars that account for a large amount of baryonic dark matter. As opposed to this, cold-dark-matter-dominated cosmologies that suggest a more gradual hierarchical buildup through mergers of minor structures, though popular, are a poor description for the Milky Way Galaxy , and by inference many other spirals as well , if, as the sample implies, the fossil records of its long-lived stars do not stick to this paradigm. Apart from this general picture that emerges with reference to the entire sample stars, a good deal of the present work is however also concerned with detailed discussions of many individual objects. Among the most interesting we mention the blue straggler or merger candidates HD 165401 and HD 137763/HD 137778, the likely accretion of a giant planet or brown dwarf on 59 Vir in its recent history, and HD 63433 that proves to be a young solar analog at , , 200 Myr. Likewise, the secondary to HR 4867, formerly suspected non-single from the Hipparcos astrometry, is directly detectable in the highresolution spectroscopic tracings, whereas the visual binary , Cet is instead at least triple, and presumably even quadruple. With respect to the nearby young stars a complete account of the UrsaMajor Association is presented, and we provide as well plain evidence for another, the "Hercules-Lyra Association", the likely existence of which was only realized in recent years. On account of its rotation, chemistry, and age we do confirm that the Sun is very typical among its G-type neighbors; as to its kinematics, it appears however not unlikely that the Sun's known low peculiar space velocity could indeed be the cause for the weak paleontological record of mass extinctions and major impact events on our parent planet during the most recent Galactic plane passage of the solar system. Although the significance of this correlation certainly remains a matter of debate for years to come, we point in this context to the principal importance of the thick disk for a complete census with respect to the local surface and volume densities. Other important effects that can be ascribed to this dark stellar population comprise (i) the observed plateau in the shape of the luminosity function of the local FGK stars, (ii) a small though systematic effect on the basic solar motion, (iii) a reassessment of the term "asymmetrical drift velocity" for the remainder (i.e. the thin disk) of the stellar objects, (iv) its ability to account for the bulk of the recently discovered high-velocity blue white dwarfs, (v) its major contribution to the Sun's ,220 km s,1 rotational velocity around the Galactic center, and (vi) the significant flattening that it imposes on the Milky Way's rotation curve. Finally we note a high multiplicity fraction in the small but volume-complete local sample of stars of this ancient population. This in turn is highly suggestive for a star formation scenario wherein the few existing single stellar objects might only arise from either late mergers or the dynamical ejection of former triple or higher level star systems. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Mid-Infrared Imaging and Spectroscopic Observations of the Galactic Center with Subaru/COMICSASTRONOMISCHE NACHRICHTEN, Issue S1 2003Y. Okada Abstract We report the results of mid-infrared (7.8,m,13.2 ,m) high-spatial resolution imaging and spectroscopic observations of the Galactic center region with the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru telescope. The images clearly show bright infrared sources and small structures in the diffuse emission. The spectra of all the observed positions show the 9.7 ,m silicate absorption feature. After corrected for the empirically-derived extinction, the intrinsic spectra of the infrared sources show either strong silicate emission or absorption, while the intrinsic diffuse emission has a power-law type spectrum. This difference indicates a possibility of dust processing due to the interaction between the infrared sources and their surrounding medium or a different origin of the dust grains surrounding the sources from those in the diffuse region. [source] The source content of low galactic latitude XMM-Newton surveysASTRONOMISCHE NACHRICHTEN, Issue 1-2 2003C. Motch Abstract We present results from a project conducted by the Survey Science Center of the XMM-Newton satellite and aiming at the identification and characterisation of serendipitous EPIC sources at low galactic latitudes. Deep multi-colour optical imaging and spectroscopic observations have been obtained in the framework of several observing campaigns carried out at ING, CFHT and ESO. These observations have lead to a number of optical identifications, mostly with active stars. We describe the identified source content at low galactic latitudes and compare stellar populations properties at low and high galactic latitudes with those expected from stellar X-ray count models. [source] Characterization of O2,CeO2 Interactions Using In Situ Raman Spectroscopy and First-Principle CalculationsCHEMPHYSCHEM, Issue 9 2006Y. M. Choi Dr. Abstract Interactions between O2 and CeO2 are examined experimentally using in situ Raman spectroscopy and theoretically using density-functional slab-model calculations. Two distinct oxygen bands appear at 825 and 1131 cm,1, corresponding to peroxo- and superoxo-like species, respectively, when partially reduced CeO2 is exposed to 10,% O2. Periodic density-functional theory (DFT) calculations aid the interpretation of spectroscopic observations and provide energetic and geometric information for the dioxygen species adsorbed on CeO2. The O2 adsorption energies on unreduced CeO2 surfaces are endothermic (0.91<,Eads<0.98 eV), while those on reduced surfaces are exothermic (,4. 0<,Eads<,0.9 eV), depending on other relevant surface processes such as chemisorption and diffusion into the bulk. Partial reduction of surface Ce4+ to Ce3+ (together with formation of oxygen vacancies) alters geometrical parameters and, accordingly, leads to a shift in the vibrational frequencies of adsorbed oxygen species compared to those on unreduced CeO2. Moreover, the location of oxygen vacancies affects the formation and subsequent dissociation of oxygen species on the surfaces. DFT predictions of the energetics support the experimental observation that the reduced surfaces are energetically more favorable than the unreduced surfaces for oxygen adsorption and reduction. [source] Spectroscopic rationalization of the separation abilities of decaproline chiral selector in dichloromethane,isopropanol solvent mixtureCHIRALITY, Issue 2 2007Peng Zhang Abstract A chiral column, with decaproline as the chiral selector, has broad chiral selectivity. To understand the separation mechanism of this chiral column, multiple spectroscopic techniques, including optical rotation, electronic circular dichroism, infrared absorption and vibrational circular dichroism, have been used here to study the conformation of the decaproline oligomer in isopropanol(IPA)/dichloromethane(DCM) mixtures. These studies indicate that decaproline oligomer adopts polyproline II conformation in IPA/DCM solvent system (0% IPA , 100% IPA). Hydrogen bonding interactions between CO groups of decaproline and IPA molecules increase as the content of IPA in the solvent mixture increases up to 60% and become less significant from then onwards. These spectroscopic observations are found to have a good correlation with the enantiomeric separation of racemic 2,2,2-trifluoro-1-[10-(2,2,2-trifluoro-1-hydroxy-ethyl-anthracen-9-yl]-ethanol by the decaproline column. Chirality 2006. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||