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A radial velocity survey of low Galactic latitude structures - I. Kinematics of the Canis Major dwarf galaxy
As part of a radial velocity survey of low Galactic latitude structuresthat we undertook with the 2dF spectrograph on the Anglo-AustralianTelescope, we present the radial velocities of more than 1500 red giantbranch and red clump stars towards the centre of the Canis Major dwarfgalaxy. With a mean velocity of 72 +/- 7kms-1 at aheliocentric distance of 5.5kpc and 114 +/- 2kms-1 at 8.5kpc,these stars present a peculiar distance - radial velocity relation thatis unlike that expected from thin or thick disc stars. Moreover, theybelong to a kinematically cold population with an intrinsic dispersionthat may be as low as 11+3-1kms-1. Acomparison of the velocity distribution obtained in this work withprevious studies shows the importance of using our new reductionpipeline and averaging the velocities obtained from different templates.The radial velocity distribution is used to select Canis Major stars inthe UCAC2.0 proper motion catalogue and derive proper motions inGalactic coordinates of (μl, μb) = (-3.6 +/-0.8masyr-1, 1.5 +/- 0.4masyr-1) for the dwarfgalaxy, which after correcting for the reflex solar motion along thisline of sight gives (μ'l, μ'b) = (-6.8 +/-0.8masyr-1, 0.8 +/- 0.4masyr-1), corresponding toa prograde orbit with a tangential velocity of ~235kms-1 atthe average distance of ~7.2kpc. All these kinematic constraints can bereproduced in simulations of the accretion of a dwarf on to the Galacticdisc. Such a process could also be responsible for the Monoceros Ringthat has recently been shown to encompass the Galactic disc. However,without constraints on the kinematics of the tidal arms emerging fromthe Canis Major dwarf, it is not yet possible to definitively prove alink between the two structures.
| First results from the ESO VLTI calibrators program
The ESO Very Large Telescope Interferometer (VLTI) is one of the leadinginterferometric facilities. It is equipped with several 8.2 and 1.8 mtelescopes, a large number of baselines up to 200 m, and with severalsubsystems designed to enable high quality measurements and to improvesignificantly the limits of sensitivities currently available tolong-baseline interferometry. The full scientific potential of the VLTIcan be exploited only if a consistent set of good quality calibrators isavailable. For this, a large number of observations of potentialcalibrators have been obtained during the commissioning phase of theVLTI. These data are publicly available. We briefly describe theinterferometer, the VINCI instrument used for the observations, the dataflow from acquisition to processed results, and we present and commenton the volume of observations gathered and scrutinized. The result is alist of 191 calibrator candidates, for which a total of 12 066observations can be deemed of satisfactory quality. We present a generalstatistical analysis of this sample, using as a starting point theangular diameters previously available in the literature. We derive thegeneral characteristics of the VLTI transfer function, and its trendwith time in the period 2001 through mid-2004. A second paper will bedevoted to a detailed investigation of a selected sample, aimed atestablishing a VLTI-based homogeneous system of calibrators.
| CHARM2: An updated Catalog of High Angular Resolution Measurements
We present an update of the Catalog of High Angular ResolutionMeasurements (CHARM, Richichi & Percheron \cite{CHARM}, A&A,386, 492), which includes results available until July 2004. CHARM2 is acompilation of direct measurements by high angular resolution methods,as well as indirect estimates of stellar diameters. Its main goal is toprovide a reference list of sources which can be used for calibrationand verification observations with long-baseline optical and near-IRinterferometers. Single and binary stars are included, as are complexobjects from circumstellar shells to extragalactic sources. The presentupdate provides an increase of almost a factor of two over the previousedition. Additionally, it includes several corrections and improvements,as well as a cross-check with the valuable public release observationsof the ESO Very Large Telescope Interferometer (VLTI). A total of 8231entries for 3238 unique sources are now present in CHARM2. Thisrepresents an increase of a factor of 3.4 and 2.0, respectively, overthe contents of the previous version of CHARM.The catalog is only available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/431/773
| On the analysis of band 3 of the ISO-SWS calibration sources
We analyse ISO-SWS 01 (R 1500) 12-27.5 μm (band 3) spectra ofthe 10 standard calibration stars with the highest flux using syntheticspectra generated from (MARCS) atmosphere models. The comparison betweenthe observed and synthetic spectra reveals the quality of (1) theatmospheric model construction and subsequent synthetic spectracomputation and of (2) the (OLP 10.1) calibration and data reduction ofthe spectrometer at these wavelengths.The models represent the general features of the observations, but thesynthetic spectrum computation is hampered by the lack of comprehensivemolecular and atomic line lists. We also suspect some problems with thetemperature distribution in the outer layers of the model andinaccuracies in the extrapolation of the collision-induced absorptioncoefficients of H2 pairs. We detect baseline ripples andfringes in the observed spectra, that survive the calibration anddetailed reduction process. Photometric calibration uncertainties areestimated by means of the scaling factors between the synthetic andobserved spectra.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.
| ISO-SWS calibration and the accurate modelling of cool-star atmospheres. IV. G9 to M2 stars
A detailed spectroscopic study of 11 giants with spectral type from G9to M2 is presented. The 2.38-4.08 mu m wavelength-range of band 1 ofISO-SWS (Short-Wavelength Spectrometers on board of the Infrared SpaceObservatory) in which many different molecules - with their owndependence on each of the stellar parameters - are absorbing, enables usto estimate the effective temperature, the gravity, the microturbulence,the metallicity, the CNO-abundances, the12C/13C-ratio and the angular diameter from theISO-SWS data. Using the Hipparcos' parallax, the radius, luminosity andgravity-inferred mass are derived. The stellar parameters obtained arein good agreement with other published values, though also somediscrepancies with values deduced by other authors are noted. For a fewstars (delta Dra, xi Dra, alpha Tuc, H Sco and alpha Cet) someparameters - e.g. the CNO-abundances - are derived for the first time.By examining the correspondence between different ISO-SWS observationsof the same object and between the ISO-SWS data and the correspondingsynthetic spectrum, it is shown that the relative accuracy of ISO-SWS inband 1 (2.38-4.08 mu m) is better than 2% for these high-flux sources.The high level of correspondence between observations and theoreticalpredictions, together with a confrontation of the estimatedTeff (ISO) value with Teff values derived fromcolours - which demonstrates the consistency between V-K,BCK, Teff and thetad derived fromoptical or IR data - proves that both the used MARCS models to derivethe stellar quantities and the flux calibration of the ISO-SWS detectorshave reached a high level of reliability.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.Appendices A-D are only available in electronic form athttp://www.edpsciences.org
| ISO-SWS calibration and the accurate modelling of cool-star atmospheres. II. General results
The fine calibration of the ISO-SWS detectors (Infrared SpaceObservatory - Short Wavelength Spectrometer) has proven to be a delicateproblem. We therefore present a detailed spectroscopic study in the2.38-12 mu m wavelength range of a sample of 16 A0-M2 stars used for thecalibration of ISO-SWS. By investigating the discrepancies between theISO-SWS data of these sources, the theoretical predictions of theirspectra, the high-resolution FTS-KP (Kitt Peak) spectrum of alpha Booand the solar FTS-ATMOS (Atmospheric Trace Molecule Spectroscopy)spectrum, both calibration problems and problems in computing thetheoretical models and the synthetic spectra are revealed. Theunderlying reasons for these problems are sought for and the impact onthe further calibration of ISO-SWS and on the theoretical modelling isdiscussed extensively.Based on observations with ISO, an ESA project with instruments fundedby ESA Member States (especially the PI countries France, Germany, TheNetherlands and the UK) and with the participation of ISAS and NASA.Appendix is only available in electronic form athttp://www.edpsciences.org
| Infrared spectral classification of normal stars.
Moderate resolution (~400) 2.38-45.2 mu m infrared spectra of starswithout dust features were obtained with the Short WavelengthSpectrometer (SWS) on board the Infrared Space Observatory (ISO). Theobservations are part of a larger program with the objective to extendand refine the current infrared classification schemes. In particular,our data provide the basis for a more detailed classification of the1.N-1.NO sources (ordinary and oxygen rich naked stars) as defined byKraemer et al. (\cite{kraemer}) in a comprehensive classification of theISO-SWS spectra. For our analysis, the continuum was determined byfitting Engelke's function (Engelke \cite{engelke}) to the SWS data. Thestellar angular diameters derived from these estimates of the continuumare in good agreement with values obtained by other methods. Analysis ofthe equivalent widths of the CO fundamental and first overtone molecularbands, the SiO fundamental and first overtone, as well as theH2O bending mode band as a function of MK class, reveals thatthere is sufficient information in the SWS spectra to distinguishbetween hot (B, A, F) and cool stars. Furthermore, it is possible todetermine the spectral type for the G, K and M giants, and subtyperanges in a sequence of K and M giants. The equivalent widths of the COand SiO bands are found to be well correlated in K and M stars, suchthat the equivalent widths of the CO fundamental, the SiO first overtoneand the SiO fundamental can be reasonably well extrapolated from thedepth of the CO first overtone. We have identified two stars,HR 365 and V Nor, whosemid-infrared spectrum does not correspond to their respective opticalclassification. HR 365 may have a late M companion,which dominates the observed infrared spectrum while VNor is a late type giant that was included because itsspectrum was classified as featureless under the IRAS LRS scheme.According to Kraemer et al. (\cite{kraemer}), V Norhas a thin dust shell, which distorts the analysis of its mid-infraredabsorption bands. Based on observations with ISO, an ESA project withinstruments funded by ESA Member States (especially the PI countries:France, Germany, The Netherlands and the UK) and with the participationof ISAS and NASA.
| A catalogue of calibrator stars for long baseline stellar interferometry
Long baseline stellar interferometry shares with other techniques theneed for calibrator stars in order to correct for instrumental andatmospheric effects. We present a catalogue of 374 stars carefullyselected to be used for that purpose in the near infrared. Owing toseveral convergent criteria with the work of Cohen et al.(\cite{cohen99}), this catalogue is in essence a subset of theirself-consistent all-sky network of spectro-photometric calibrator stars.For every star, we provide the angular limb-darkened diameter, uniformdisc angular diameters in the J, H and K bands, the Johnson photometryand other useful parameters. Most stars are type III giants withspectral types K or M0, magnitudes V=3-7 and K=0-3. Their angularlimb-darkened diameters range from 1 to 3 mas with a median uncertaintyas low as 1.2%. The median distance from a given point on the sky to theclosest reference is 5.2degr , whereas this distance never exceeds16.4degr for any celestial location. The catalogue is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/393/183
| The ISO-SWS post-helium atlas of near-infrared stellar spectra
We present an atlas of near-infrared spectra (2.36 mu m-4.1 mu m) of ~300 stars at moderate resolution (lambda /delta lambda ~ 1500-2000). Thespectra were recorded using the Short-Wavelength Spectrometer aboard theInfrared Space Observatory (ISO-SWS). The bulk of the observations wereperformed during a dedicated observation campaign after the liquidhelium depletion of the ISO satellite, the so-called post-heliumprogramme. This programme was aimed at extending the MK-classificationto the near-infrared. Therefore the programme covers a large range ofspectral types and luminosity classes. The 2.36 mu m-4.05 mu m region isa valuable spectral probe for both hot and cool stars. H I lines(Bracket, Pfund and Humphreys series), He I and He II lines, atomiclines and molecular lines (CO, H2O, NH, OH, SiO, HCN,C2H2, ...) are sensitive to temperature, gravityand/or the nature of the outer layers of the stellar atmosphere(outflows, hot circumstellar discs, etc.). Another objective of theprogramme was to construct a homogeneous dataset of near-infraredstellar spectra that can be used for population synthesis studies ofgalaxies. At near-infrared wavelengths these objects emit the integratedlight of all stars in the system. In this paper we present the datasetof post-helium spectra completed with observations obtained during thenominal operations of the ISO-SWS. We discuss the calibration of the SWSdata obtained after the liquid helium boil-off and the data reduction.We also give a first qualitative overview of how the spectral featuresin this wavelength range change with spectral type. The dataset isscrutinised in two papers on the quantitative classification ofnear-infrared spectra of early-type stars ({Lenorzer} et al.\cite{lenorzer:2002a}) and late-type stars (Vandenbussche et al., inprep). Based on observations with ISO, an ESA project with instrumentsfunded by ESA Members States (especially the PI countries France,Germany, the Netherlands and the United Kingdom) and with theparticipation of ISAS and NASA. The full atlas is available inelectronic form at www.edpsciences.org Table 1 is only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?/A+A/390/1033
| CHARM: A Catalog of High Angular Resolution Measurements
The Catalog of High Angular Resolution Measurements (CHARM) includesmost of the measurements obtained by the techniques of lunaroccultations and long-baseline interferometry at visual and infraredwavelengths, which have appeared in the literature or have otherwisebeen made public until mid-2001. A total of 2432 measurements of 1625sources are included, along with extensive auxiliary information. Inparticular, visual and infrared photometry is included for almost allthe sources. This has been partly extracted from currently availablecatalogs, and partly obtained specifically for CHARM. The main aim is toprovide a compilation of sources which could be used as calibrators orfor science verification purposes by the new generation of largeground-based facilities such as the ESO Very Large Interferometer andthe Keck Interferometer. The Catalog is available in electronic form atthe CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/386/492, and from theauthors on CD-Rom.
| Infrared optical properties of spinels. A study of the carrier of the 13, 17 and 32 mu m emission features observed in ISO-SWS spectra of oxygen-rich AGB stars
In a previous paper, we have proposed magnesium aluminium spinel to bethe carrier of the 13 and 17 mu m band features observed in the ISOspectra of some red giants. The IR optical properties of spinel stronglydepend on its chemistry and its internal structure. To study thedependence of spinel's IR-spectra on its aluminium content, we havesynthesized a number of crystals with different Al/Mg-ratios.Additionally, we performed an annealing experiment to investigate thephase transition between ordered and partially disordered spinel takingplace at about 1200 K. We derived sets of optical constants of ournatural, annealed and synthetic spinels in order to calculate theabsorption efficiencies of small (sub-mu m-sized) spherical particles.Thereby, it turned out that natural as well as near-stoichiometricsynthetic spinel can indeed be considered as a suitable candidate forthe carrier of the 13 mu m feature observed in the spectra of someoxygen rich circumstellar shells. To illustrate this, we reinvestigatedthe mean profile of the residual dust emission in the 12-18 mu mwavelength range (i.e., in the so-called trough region between the twosilicate bands). The reality of the emission feature at 16.8 mu m isconfirmed by our new investigation. We demonstrated that it is not aninstrumental artifact since it is not present in ISO spectra of K-stars.In the course of our laboratory work, we found a third prominentemissivity maximum of spinel at 32 mu m. This feature could also bedetected in the spectra of the brightest 13 mu m band emission sources;we derived its mean band profile, too. The new sets of optical constantshere presented have been made available for public access in theelectronic database http://www.astro.uni-jena.de. Based on observationswith ISO, an ESA project with instruments funded by ESA Member States(especially the PI countries: France, Germany, The Netherlands and theUK) and with the participation of ISAS and NASA.
| Spectroscopic binary orbits from photoelectric radial velocities. Paper 148: HR 7955
Not Available
| Spectral Irradiance Calibration in the Infrared. X. A Self-Consistent Radiometric All-Sky Network of Absolutely Calibrated Stellar Spectra
We start from our six absolutely calibrated continuous stellar spectrafrom 1.2 to 35 μm for K0, K1.5, K3, K5, and M0 giants. These wereconstructed as far as possible from actual observed spectral fragmentstaken from the ground, the Kuiper Airborne Observatory, and the IRAS LowResolution Spectrometer, and all have a common calibration pedigree.From these we spawn 422 calibrated ``spectral templates'' for stars withspectral types in the ranges G9.5-K3.5 III and K4.5-M0.5 III. Wenormalize each template by photometry for the individual stars usingpublished and/or newly secured near- and mid-infrared photometryobtained through fully characterized, absolutely calibrated,combinations of filter passband, detector radiance response, and meanterrestrial atmospheric transmission. These templates continue ourongoing effort to provide an all-sky network of absolutely calibrated,spectrally continuous, stellar standards for general infrared usage, allwith a common, traceable calibration heritage. The wavelength coverageis ideal for calibration of many existing and proposed ground-based,airborne, and satellite sensors, particularly low- tomoderate-resolution spectrometers. We analyze the statistics of probableuncertainties, in the normalization of these templates to actualphotometry, that quantify the confidence with which we can assert thatthese templates truly represent the individual stars. Each calibratedtemplate provides an angular diameter for that star. These radiometricangular diameters compare very favorably with those directly observedacross the range from 1.6 to 21 mas.
| Classification and Identification of IRAS Sources with Low-Resolution Spectra
IRAS low-resolution spectra were extracted for 11,224 IRAS sources.These spectra were classified into astrophysical classes, based on thepresence of emission and absorption features and on the shape of thecontinuum. Counterparts of these IRAS sources in existing optical andinfrared catalogs are identified, and their optical spectral types arelisted if they are known. The correlations between thephotospheric/optical and circumstellar/infrared classification arediscussed.
| The Pulkovo Spectrophotometric Catalog of Bright Stars in the Range from 320 TO 1080 NM
A spectrophotometric catalog is presented, combining results of numerousobservations made by Pulkovo astronomers at different observing sites.The catalog consists of three parts: the first contains the data for 602stars in the spectral range of 320--735 nm with a resolution of 5 nm,the second one contains 285 stars in the spectral range of 500--1080 nmwith a resolution of 10 nm and the third one contains 278 stars combinedfrom the preceding catalogs in the spectral range of 320--1080 nm with aresolution of 10 nm. The data are presented in absolute energy unitsW/m(2) m, with a step of 2.5 nm and with an accuracy not lower than1.5--2.0%.
| Vitesses radiales. Catalogue WEB: Wilson Evans Batten. Subtittle: Radial velocities: The Wilson-Evans-Batten catalogue.
We give a common version of the two catalogues of Mean Radial Velocitiesby Wilson (1963) and Evans (1978) to which we have added the catalogueof spectroscopic binary systems (Batten et al. 1989). For each star,when possible, we give: 1) an acronym to enter SIMBAD (Set ofIdentifications Measurements and Bibliography for Astronomical Data) ofthe CDS (Centre de Donnees Astronomiques de Strasbourg). 2) the numberHIC of the HIPPARCOS catalogue (Turon 1992). 3) the CCDM number(Catalogue des Composantes des etoiles Doubles et Multiples) byDommanget & Nys (1994). For the cluster stars, a precise study hasbeen done, on the identificator numbers. Numerous remarks point out theproblems we have had to deal with.
| A Spectrophotometric Catalogue of 60 Selected Southern Stars
Not Available
| Einstein Observatory magnitude-limited X-ray survey of late-type giant and supergiant stars
Results are presented of an extensive X-ray survey of 380 giant andsupergiant stars of spectral types from F to M, carried out with theEinstein Observatory. It was found that the observed F giants orsubgiants (slightly evolved stars with a mass M less than about 2 solarmasses) are X-ray emitters at the same level of main-sequence stars ofsimilar spectral type. The G giants show a range of emissions more than3 orders of magnitude wide; some single G giants exist with X-rayluminosities comparable to RS CVn systems, while some nearby large Ggiants have upper limits on the X-ray emission below typical solarvalues. The K giants have an observed X-ray emission level significantlylower than F and F giants. None of the 29 M giants were detected, exceptfor one spectroscopic binary.
| Walraven photometry of nearby southern OB associations
Homogeneous Walraven (VBLUW) photometry is presented for 5260 stars inthe regions of five nearby southern OB associations: Scorpio Centaurus(Sco OB2), Orion OB1, Canis Major OB1, Monoceros OB1, and Scutum OB2.Derived V and (B - V) in the Johnson system are included.
| IRAS catalogues and atlases - Atlas of low-resolution spectra
Plots of all 5425 spectra in the IRAS catalogue of low-resolutionspectra are presented. The catalogue contains the average spectra ofmost IRAS poiont sources with 12 micron flux densities above 10 Jy.
| CO observations of dark clouds in Lupus
C-12O observations covering 170 square degrees toward the southern TAssociation Lupus have revealed the presence of an extended physicallyrelated complex of dark clouds which have recently formed low massstars. The estimated mass of the clouds (about 30,000 solar masses) iscomparable to that of the nearby Ophiuchus dust clouds. The Lupus cloudsare projected onto a gap between two subgroups of the Scorpio-CentaurusOB association suggesting that this long accepted subgrouping mayrequire reinterpretation.
| Trigonometric parallax results for southern luminosity class III stars
New trigonometric parallaxes are reported for ten bright, southernlate-type MK giants ranging in spectral type from K0 to M3.5. The listincludes HR 794, 1247, 2245, 2773, 3518, 3803, 5287, 5603, 6832, and6913. The modern parallaxes are compared with earlier results, and theluminosity calibration for these stars is discussed. A list of giants ispresented containing the best prospects for future parallax work onlate-type MK giants.
| A Luminosity Index for Bright K0-K5 Stars
Not Available
| Luminosity and velocity distribution of high-luminosity stars near the sun. II. The young disk giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973PASP...85..379E&db_key=AST
| Narrow-Band and Broad-Band Photometry of Red Stars. III. Southern Giants
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1970ApJ...161..199E&db_key=AST
| Results of an infrared stellar survey.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1968AJ.....73..431P&db_key=AST
| Stellar groups, VI. Space motions of the dwarf A-type and giant M-type stars in the solar neighbourhood
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1960MNRAS.120..448E&db_key=AST
| The radial velocities of 185 stars observed at the Cape.
Not Available
| The radial velocities of 60 southern stars.
Not Available
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משמש של הקבוצה הבאה
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תצפית ומידע אסטרומטרי
| קבוצת-כוכבים: | עקרב |
| התרוממות ימנית: | 16h36m22.50s |
| סירוב: | -35°15'20.0" |
| גודל גלוי: | 4.16 |
| מרחק: | 103.842 פארסק |
| תנועה נכונה: | 15.2 |
| תנועה נכונה: | 12.3 |
| B-T magnitude: | 6.238 |
| V-T magnitude: | 4.346 |
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INHABITED SKY
