The z distribution of hydrogen clouds and masers with kinematic distances

Бобылев, В. В.; Bajkova, A. T.

doi:10.1134/s1063773716030026

Cited by 23 publications

(29 citation statements)

References 32 publications

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“…The latter can be drawn using a random generator from a Gaussian distribution with a mean of 0 pc and σ = 25 pc since massive young stars are found to be born close to the Galactic plane (see e.g. Bobylev & Bajkova 2016).…”

Section: Spatial Distributionmentioning

confidence: 99%

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

Quiroga-Nuñez

Langevelde

Reid

et al. 2017

A&A

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Context. Using trigonometric parallaxes and proper motions of masers associated with massive young stars, the Bar and Spiral Structure Legacy (BeSSeL) survey has reported the most accurate values of the Galactic parameters so far. The determination of these parameters with high accuracy has a widespread impact on Galactic and extragalactic measurements. Aims. This research is aimed at establishing the confidence with which such parameters can be determined. This is relevant for the data published in the context of the BeSSeL survey collaboration, but also for future observations, in particular from the southern hemisphere. In addition, some astrophysical properties of the masers can be constrained, notably the luminosity function. Methods. We have simulated the population of maser-bearing young stars associated with Galactic spiral structure, generating several samples and comparing them with the observed samples used in the BeSSeL survey. Consequently, we checked the determination of Galactic parameters for observational biases introduced by the sample selection. Results. Galactic parameters obtained by the BeSSeL survey do not seem to be biased by the sample selection used. In fact, the published error estimates appear to be conservative for most of the parameters. We show that future BeSSeL data and future observations with southern arrays will improve the Galactic parameters estimates and smoothly reduce their mutual correlation. Moreover, by modeling future parallax data with larger distance values and, thus, greater relative uncertainties for a larger numbers of sources, we found that parallax-distance biasing is an important issue. Hence, using fractional parallax uncertainty in the weighting of the motion data is imperative. Finally, the luminosity function for 6.7 GHz methanol masers was determined, allowing us to estimate the number of Galactic methanol masers.

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Section: Spatial Distributionmentioning

confidence: 99%

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

Quiroga-Nuñez

Langevelde

Reid

et al. 2017

A&A

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“…Using the original distances to (U, V, W ) ⊙ = (16,26,9) Once all distance were multiplied by the factor 0.8, we found the following kinematic (9) and (10). When there are only the line-of-sight velocities for PNe, the components of their circular rotation velocities V circ are calculated from the well-known formula…”

Section: The Galactic Rotation Parametersmentioning

confidence: 99%

Vertical distribution and kinematics of planetary nebulae in the milky way

Бобылев

Bajkova

2017

Astron. Lett.

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Based on published data, we have produced a sample of planetary nebulae (PNe) that is complete within 2 kpc of the Sun. We have estimated the total number of PNe in the Galaxy from this sample to be 17000 ± 3000 and determined the vertical scale height of the thin disk based on an exponential density distribution to be 197 ± 10 pc. The next sample includes PNe from the Stanghellini-Haywood catalog with minor additions. For this purpose, we have used ∼200 PNe with Peimbert's types I, II, and III. In this case, we have obtained a considerably higher value of the vertical scale height that increases noticeably with sample radius. We have experimentally found that it is necessary to reduce the distance scale of this catalog approximately by 20%. Then, for example, for PNe with heliocentric distances less than 4 kpc the vertical scale height is 256 ± 12 kpc. A kinematic analysis has confirmed the necessity of such a reduction of the distance scale.

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“…After considering the effects of the local spiral arm, the Gould Belt and the Galactic warp, they obtained z ⊙ = 5.7±0.5 pc for methanol masers, z ⊙ = 7.6±0.4 pc for HII regions and z ⊙ = 10.1±0.5 pc for giant molecular clouds. Conti & Vacca (1990) Wolf-Rayet stars 15±3 Humphreys & Larsen (1995) optical stars 20.5±3.5 Chen et al (2001) optical stars 27±4 Maíz-Apellániz (2001) OB stars 24.2±1.8 Joshi (2007) OB stars 6-28 open clusters 13-20 Majaess et al (2009) Cepheid variables 26±3 Buckner & Froebrich (2014) open clusters 18.5±1.2 Olausen & Kaspi (2014) magnetars 13.9±2.5 Bobylev & Bajkova (2016) methanol masers 5.7±0.5 HII regions 7.6±0.4 giant molecular clouds 10.1±0.5 Joshi et al (2016) open clusters 6.2±1.1 clusters within 1.8 kpc of the Sun and fitted an exponential profile to the data sets, resulting in z ⊙ = 6.2±1.1 pc. An analysis by Buckner & Froebrich (2014) of a different sample of open clusters gave a much larger value of z ⊙ , 18.5 ± 1.2 pc.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Sun's offset from the Galactic plane using pulsars

Yao

Manchester

Wang

2017

Monthly Notices of the Royal Astronomical Society

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We derive the Sun's offset from the local mean Galactic plane(z ⊙ ) using the observed z distribution of young pulsars. Pulsar distances are obtained from measurements of annual parallax, HI absorption spectra or associations where available and otherwise from the observed pulsar dispersion and a model for the distribution of free electrons in the Galaxy. We fit the cumulative distribution function for a sech 2 (z) distribution function, representing an isothermal self-gravitating disk, with uncertainties being estimated using the bootstrap method. We take pulsars having characteristic age τ c < ∼ 10 6.5 yr and located within 4.5 kpc of the Sun, omitting those within the local spiral arm and those significantly affected by the Galactic warp, and solve for z ⊙ and the scale height, H, for different cutoffs in τ c . We compute these quantities using just the independently determined distances, and these together with DM-based distances separately using the YMW16 and NE2001 Galactic electron density models. We find that an age cutoff at 10 5.75 yr with YMW16 DM-distances gives the best results with a minimum uncertainty in z ⊙ and an asymptotically stable value for H showing that, at this age and below, the observed pulsar z-distribution is dominated by the dispersion in their birth locations. From this sample of 115 pulsars, we obtain z ⊙ = 13.4±4.4 pc and H = 56.9±6.5 pc, similar to estimated scale heights for OB stars and open clusters. Consistent results are obtained using the independent-only distances and using the NE2001 model for the DM-based distances.

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The z distribution of hydrogen clouds and masers with kinematic distances

Cited by 23 publications

References 32 publications

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

Simulated Galactic methanol maser distribution to constrain Milky Way parameters

Vertical distribution and kinematics of planetary nebulae in the milky way

Determination of the Sun's offset from the Galactic plane using pulsars

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