Density Wave Streaming Motions in Stars along the Sagittarius Spiral Arm

Fresneau, A.; Vaughan, A. E.; Argyle, R. W.

doi:10.1086/497288

Cited by 13 publications

(17 citation statements)

References 95 publications

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“…We note that Fresneau et al (2007) found no colour effect when deriving p.m. at the level of 0.002 yr −1 by comparing century-old astrographic observations and second-epoch Schmidt telescope ones used in the GSC 1.2 construction. While that result was based on Tycho-2 stars (Hog et al 2000) brighter than m b = 12 (Fresneau et al 2005), we presume it is valid for even fainter stars, and hence no severe systematic effect has been introduced into the data by our proper motion determinations. We see in Fig.…”

Section: Validity Of the Rpmd For Stellar Group Classification In Sogsmentioning

confidence: 61%

“…These relations follow from the assumption that the mean dispersion of the transverse velocity of foreground stars observed along the direction of each 2 • × 2 • field of view is on the order of 45 km s −1 (Fresneau et al 2003). These relations between H b and M b are based on a different stellar sample (Fresneau et al 2005) One then finds a correlation between the statistically derived parallax π in 10 −3 arcsec and the p.m. total component μ in 10 −3 arcsec yr −1 -π = (0.072 ± 0.001)μ + (0.284 ± 0.005) -which is similar to the relation that was found using stars with measured trigonometric parallax π ≥ 10 −3 arcsec and p.m. μ ≥ 10 −2 arcsec yr −1 in the space-based Hipparcos survey of stars brighter than apparent magnitude 11 (Fresneau et al 2005 Table 9 of Chiu 1980), short-term apparent magnitude scatter σ 1 , long-term apparent magnitude scatter σ 2 , error in absolute magnitude determination due to the p.m. component error σ 3 = 2.17 Δμ μ , annual p.m. in arcsec in galactic longitude μ 1 and in galactic latitude μ 2 , derived parallax π in milliarcsec, and a correlation coefficient c, which has values from 0 to 1.0 and will be explained later in our study. We also give our adopted classification of the star as a Pop.…”

Section: Construction Of the Variability Sample Catalog (Vsc)mentioning

confidence: 99%

“…The catalog is available on line through the VizieR system 1 with catalogue identifications J/AJ/130/2701 for the section along the galactic equator and J/A+A/469/1221 for the section along the Data files are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/503/1023 1 http://vizier.u-strasbg.fr/viz-bin/VizieR galactic meridian. Additional details about the SOGS are given in Fresneau et al (2005Fresneau et al ( , 2007.…”

Section: General Characteristics Of the Sydney Observatory Galactic Smentioning

confidence: 99%

“…The 30-min plates have mean epochs 1915 or later and a limiting b-magnitude of 14.5 and were were intended to permit star images to be separated from plate defects; b. the 660 fields centered on odd-degree declinations were photographed with a single exposure of 80 min. These plates have epochs earlier than 1915 and the increased exposure time gave a limiting b-magnitude of about 16; c. some very long exposure plates (3-6 h) were taken by the SOAP observers to be used to make prints of objects of special interest (Russell 1891); these have a b-magnitude limit down to 18 as determined from a set of ten plates of the LMC (Fresneau et al 2005). …”

Section: General Characteristics Of the Sydney Observatory Galactic Smentioning

confidence: 99%

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A variability sample catalogue selected from the Sydney Observatory Galactic Survey

Fresneau

Osborn²

2009

A&A

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Context. A set of 55 × 10 3 stars brighter than about B-magnitude 14 and having at least three observations are identified in the Sydney Observatory Galactic Survey, carried out over the years 1892-1932 along the galactic equator section l ∈ [275. Short-term (30 min) and long-term (decades) magnitude variations in the data set are analyzed. Aims. Evidence is sought for a correlation between short-term and long-term variabilities which would identify stars in a non-quiescent phase. Methods. We use a reduced proper motion diagram to classify the stars in our sample into probable dwarfs, giants and other types. The validity of the kinematical classification is checked using objective-prism spectroscopic classification for 10 × 10 3 early-type stars. A search is made for statistical correlations between our variability indicators and physical and kinematical stellar properties. Results. We find that suspected photospheric activity for giant and dwarf stellar candidates is correlated with the time to cross the galactic thin disk. We estimate a significant apparent B-magnitude variation of ±0.25 over the 40 years of photographic observations, and candidates for monitoring for possible photospheric activity at the present time are selected employing a statistical colour-diagram which uses the total proper motion component as a distance indicator. Conclusions. Follow up studies of our tentative findings are suggested. Toward this aim the derived data for the set of 55 × 10 3 stars with variability information is archived as the variability Sample Catalogue. The data for a set of 2.4 × 10 5 stars along the section of the galactic equator l ∈ [275 • , 335 • ], |b| ≤ 7 • , and a set of of 1.7 × 10 5 stars along the section of the galactic meridian 330 • ± 5 • , b ∈ [−64 • , −7 • ] is also archived as a quick-look facility for seeking long-term magnitude changes since the century-old photographic observations were obtained.

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Section: Validity Of the Rpmd For Stellar Group Classification In Sogsmentioning

confidence: 61%

Section: Construction Of the Variability Sample Catalog (Vsc)mentioning

confidence: 99%

Section: General Characteristics Of the Sydney Observatory Galactic Smentioning

confidence: 99%

Section: General Characteristics Of the Sydney Observatory Galactic Smentioning

confidence: 99%

See 2 more Smart Citations

A variability sample catalogue selected from the Sydney Observatory Galactic Survey

Fresneau

Osborn²

2009

A&A

Self Cite

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“…Shetty et al 2007), and observationally (e.g. Aalto et al 1999;Fresneau et al 2005;Riffel et al 2008;Meidt et al 2013). The cloud trapping is particularly important to the fact that clouds would rarely interact with arms more than once in a dynamical timescale.…”

Section: Discussionmentioning

confidence: 99%

The onset of large-scale turbulence in the interstellar medium of spiral galaxies

Falceta‐Gonçalves¹,

Bonnell²,

Kowal³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Turbulence is ubiquitous in the interstellar medium (ISM) of the Milky Way and other spiral galaxies. The energy source for this turbulence has been much debated with many possible origins proposed. The universality of turbulence, its reported largescale driving, and that it occurs also in starless molecular clouds, challenges models invoking any stellar source. A more general process is needed to explain the observations. In this work we study the role of galactic spiral arms. This is accomplished by means of three-dimensional hydrodynamical simulations which follow the dynamical evolution of interstellar diffuse clouds (∼ 100cm −3 ) interacting with the gravitational potential field of the spiral pattern. We find that the tidal effects of the arm's potential on the cloud result in internal vorticity, fragmentation and hydrodynamical instabilities. The triggered turbulence result in large-scale driving, on sizes of the ISM inhomogeneities, i.e. as large as ∼ 100pc, and efficiencies in converting potential energy into turbulence in the range ∼ 10 to 25 % per arm crossing. This efficiency is much higher than those found in previous models. The statistics of the turbulence in our simulations are strikingly similar to the observed power spectrum and Larson scaling relations of molecular clouds and the general ISM. The dependency found from different models indicate that the ISM turbulence is mainly related to local spiral arm properties, such as its mass density and width. This correlation seems in agreement with recent high angular resolution observations of spiral galaxies, e.g. M51 and M33.

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The Potsdam plates of the Carte du Ciel project: I. Present inventory and plate catalogue

et al. 2009

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We present an inventory ofthe Carte du Ciel (CdC) plates stored in the Astrophysical Institute Potsdam. The Potsdam CdC zone (+32° to +39°) was divided into 1232 areas and about 2200 plates from the first and second epochs were obtained within the framework of the CdC project. At present, only 977 plates (45% of all) are stored in AIP, the others got lost during the Second World War. The plates for the first epoch measurements had been obtained during the period 1893 May– 1900 February. The plates for the second epoch (1913 August–1924 February) can be separated into two time intervals according to the observer and the observing method used: from 1913 August till 1914 July, and from 1916 February to 1924 February. The present work aims to provide online access to the plate information, given in the plate catalogue and is the first step to online access to the plate images digitized with flatbed scanners.

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Density Wave Streaming Motions in Stars along the Sagittarius Spiral Arm

Cited by 13 publications

References 95 publications

A variability sample catalogue selected from the Sydney Observatory Galactic Survey

A variability sample catalogue selected from the Sydney Observatory Galactic Survey

The onset of large-scale turbulence in the interstellar medium of spiral galaxies

The Potsdam plates of the Carte du Ciel project: I. Present inventory and plate catalogue

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