OB Stars in the Solar Neighborhood. II. Kinematics

Elías, Federico; Alfaro, E. J.; Cabrera-Caño, J.

doi:10.1086/505941

Cited by 34 publications

(45 citation statements)

References 42 publications

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“…Constraints on the quantity (A − B) have been derived by measuring the proper motions of different tracers. From the Cepheid proper motions measured by the Hipparcos satellite [27] [29] 1 . A value of (A − B) at the high end side is favored also by the recent fit of the proper motions of a sample of masers in massive star forming regions (one of the sample quoted above for local standard of rest velocities) to a linear parameterization of the galactic rotation curve, which finds A − B = (30.3 ± 0.9) km s −1 kpc −1 [24].…”

Section: Local Circular Velocity and Galactocentric Distancementioning

confidence: 99%

A novel determination of the local dark matter density

Catena

Ullio

2010

J. Cosmol. Astropart. Phys.

529

486

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We present a novel study on the problem of constructing mass models for the Milky Way, concentrating on features regarding the dark matter halo component. We have considered a variegated sample of dynamical observables for the Galaxy, including several results which have appeared recently, and studied a 7-or 8-dimensional parameter space -defining the Galaxy model -by implementing a Bayesian approach to the parameter estimation based on a Markov Chain Monte Carlo method. The main result of this analysis is a novel determination of the local dark matter halo density which, assuming spherical symmetry and either an Einasto or an NFW density profile is found to be around 0.39 GeV cm −3 with a 1-σ error bar of about 7%; more precisely we find a ρ DM (R 0 ) = 0.385±0.027 GeV cm −3 for the Einasto profile and ρ DM (R 0 ) = 0.389 ± 0.025 GeV cm −3 for the NFW. This is in contrast to the standard assumption that ρ DM (R 0 ) is about 0.3 GeV cm −3 with an uncertainty of a factor of 2 to 3. A very precise determination of the local halo density is very important for interpreting direct dark matter detection experiments. Indeed the results we produced, together with the recent accurate determination of the local circular velocity, should be very useful to considerably narrow astrophysical uncertainties on direct dark matter detection.

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Section: Local Circular Velocity and Galactocentric Distancementioning

confidence: 99%

A novel determination of the local dark matter density

Catena

Ullio

2010

J. Cosmol. Astropart. Phys.

529

486

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“…In fact, most authors reporting higherthan-average values selectively compared their results with previously published values for similar populations (e.g., Elias et al 2006). This could be considered selective publication bias.…”

Section: Is There a Need For Reassessment Of The Iau Recommendation?mentioning

confidence: 99%

Clustering of Local Group Distances: Publication Bias or Correlated Measurements? V. Galactic Rotation Constants

Grijs

Bono

2017

ApJS

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As part of on an extensive data mining effort, we have compiled a database of 162 Galactic rotation speed measurements at R 0 (the solar Galactocentric distance), Θ 0 . Published between 1927 and 2017 June, this represents the most comprehensive set of Θ 0 values since the 1985 meta analysis that led to the last revision of the International Astronomical Union's recommended Galactic rotation constants. Although we do not find any compelling evidence of the presence of 'publication bias' in recent decades, we find clear differences among the Θ 0 values and the Θ 0 /R 0 ratios resulting from the use of different tracer populations. Specifically, young tracers (including OB and supergiant stars, masers, Cepheid variables, Hii regions, and young open clusters), as well as kinematic measurements of Sgr A* near the Galactic Center, imply a significantly larger Galactic rotation speed at the solar circle and a higher Θ 0 /R 0 ratio (i.e., Θ 0 = 247 ± 3 km s −1 and Θ 0 /R 0 = 29.81 ± 0.32 km s −1 kpc −1 ; statistical uncertainties only) than any of the tracers dominating the Galaxy's mass budget (i.e., field stars and the Hi/CO distributions). Using the latter as most representative of the bulk of the Galaxy's matter distribution, we arrive at an updated set of Galactic rotation constants, Θ 0 = 225 ± 3 (statistical) ± 10 (systematic) km s −1 , R 0 = 8.3 ± 0.2 (statistical) ± 0.4 (systematic) kpc, and Θ 0 /R 0 = 27.12 ± 0.39 (statistical) ± 1.78 (systematic) km s −1 kpc −1 .

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“…However, we consider that the main factors are probably related to different physical conditions in the parental clouds or different internal structure for the gas associated with a multiscale scenario. Finally, we want to mention that besides the different geometry and kinematics shown by the GB and the LGD (see Elias et al 2006aElias et al , 2006b and references therein) the internal distribution of stars with spectral types earlier than B4 (quantified through the fractal dimension) allows us clearly to differentiate both systems. This difference could be explained in terms of a hierarchical star formation scenario.…”

Section: The Fractal Dimension Of the Gould Beltmentioning

confidence: 99%

“…Moreover, the analysis of the stellar spatial velocity diagram in the U -V plane shows a clear bimodal distribution ( Elias et al 2006a). All these results make it difficult to imagine a single monoparental origin for the GB and suggest a GB formed by a spurious concatenation of different stellar subsystems whose formation processes were not necessarily connected among them.…”

Section: Introductionmentioning

confidence: 99%

The Nature of the Gould Belt from a Fractal Analysis of Its Stellar Population

Sánchez

Alfaro

Elías

et al. 2007

ApJ

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The Gould Belt (GB) is a system of gas and young, bright stars distributed along a plane that is inclined with respect to the main plane of the Milky Way. Observational evidence suggests that the GB is our closest star formation complex, but its true nature and origin remain rather controversial. In this work we analyze the fractal structure of the stellar component of the GB. In order to do this, we tailor and apply an algorithm that estimates the fractal dimension in a precise and accurate way, avoiding both boundary and smallYdata set problems. We find that early OB stars (of spectral types earlier than B4) in the GB have a fractal dimension very similar to that of the gas clouds in our Galaxy. On the contrary, stars in the GB of later spectral types show a larger fractal dimension, similar to that found for OB stars of both age groups in the local Galactic disk (LGD). This result seems to indicate that while the younger OB stars in the GB preserve the memory of the spatial structure of the cloud where they were born, older stars are distributed following a similar morphology as that found for the LGD stars. The possible causes for these differences are discussed.

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OB Stars in the Solar Neighborhood. II. Kinematics

Cited by 34 publications

References 42 publications

A novel determination of the local dark matter density

A novel determination of the local dark matter density

Clustering of Local Group Distances: Publication Bias or Correlated Measurements? V. Galactic Rotation Constants

The Nature of the Gould Belt from a Fractal Analysis of Its Stellar Population

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