The Pulkovo Compilation of Radial Velocities (PCRV) has been made to study the stellar kinematics in the local spiral arm. The PCRV contains weighted mean absolute radial velocities for 35 495 Hipparcos stars of various spectral types and luminosity classes over the entire celestial sphere mainly within 500 pc of the Sun. The median accuracy of the radial velocities obtained is 0.7 km s −1 . Results from 203 publications were used in the catalogue. Four of them were used to improve the radial velocities of standard stars from the IAU list. The radial velocities of 155 standard stars turned out to be constant within 0.3 km s −1 . These stars were used to analyze 47 768 mean radial velocities for 37 200 stars from 12 major publications (∼ 80% of all the data used). Zero-point discrepancies and systematic dependences on radial velocity, (B − V ) color index, right ascension, and declination were found in radial velocity differences of the form "publication minus IAU list of standards". These discrepancies and dependences were approximated and taken into account when calculating the weighted mean radial velocities. 1128 stars whose independent radial-velocity determinations were available at least in three of these publications and agreed within 3 km s −1 were chosen as the work list of secondary standards. Radial-velocity differences of the form "publication minus list of secondary standards" were used by analogy to correct the zero points and systematic dependences in the radial velocities from 33 more publications ( 13% of the data used). In addition, the radial * E-mail: georgegontcharov@yahoo.com 1 velocities from 154 minor publications (∼ 7% of the data used) pertaining to well-known instruments were used without any corrections. 2 INTRODUCTIONThe stellar kinematics in the solar neighborhood within the local spiral arm of the Galaxy is being studied at the Pulkovo Astronomical Observatory of the Russian Academy of Sciences and the Astronomical Institute of the St. Petersburg State University as part of the OSACA (Orion Spiral Arm Catalogue, http://www.geocities.com/orionspiral/) project (Gontcharov 2004). The study is based on six quantities that describe the stellar positions and velocities: α, δ, π, µ α , µ δ , and V r , as well as the coordinates X, Y , and Z and space velocities U, V , and W calculated from them in the standard Galactic rectangular coordinate system, where X, Y , and Z increase in the directions of the Galactic center, the Galactic rotation, and the Galactic North Pole, respectively.At present, the coordinates and proper motions are known for a larger number of stars and with a higher relative accuracy than the parallaxes and radial velocities. For example, the coordinates and proper motions of ∼ 96000 Hipparcos stars (ESA 1997) within 500 pc of the Sun are known with a relative accuracy higher than 10 −7 and an accuracy higher than 3 km s −1 , respectively, while the parallaxes of only ∼ 69000 Hipparcos stars are known with a relative accuracy higher than 0.3 and the radial velocities of ...

A new analytical 3D model of interstellar extinction within 500 pc of the Sun as a function of the Galactic spherical coordinates is suggested. This model is physically more justified than the widely used Arenou model, since it takes into account the presence of absorbing matter both in the layer along the equatorial Galactic plane and in the Gould Belt. The extinction in the equatorial layer varies as the sine of the Galactic longitude and in the Gould Belt as the sine of twice the longitude in the Belt plane. The extinction across the layers varies according to a barometric law. It has been found that the absorbing layers intersect at an angle of 17 • and that the Sun is located near the axial plane of the absorbing layer of the Gould Belt and is probably several parsecs below the axial plane of the equatorial absorbing layer but above the Galactic plane. The model has been tested using the extinction of real stars from three catalogs.

The Tycho-2 proper motions and Tycho-2 and 2MASS photometry are used to select 97348 red giant clump (RGC) stars. The interstellar extinction and photometric distance are calculated for each of the stars. The selected stars are shown to form a selection-unbiased sample of RGC stars within about 350 pc of the Sun with the addition of more distant stars. The distribution of the selected stars in space and their motion are consistent with the assumption that the RGC contains Galactic disk stars with various ages and metallicities, including a significant fraction of stars younger than 1 Gyr with masses of more than 2 M ⊙ . These young stars show differences of their statistical characteristics from those of older RGC stars, including differences in the variations of their distribution density with distance from the Galactic plane and in the dispersion of their velocities found using radial velocities and proper motions. The Sun has been found to rise above the Galactic plane by 13 ± 1 pc. The distribution density of the stars under consideration in space is probably determined by the Local Spiral Arm and the distribution of absorbing matter in the plane of the

Pulkovo Astronomical Observatory, Russian Academy of Sciences, Pulkovskoe sh. 65, St. Petersburg, 196140 Russia Key words: Galactic solar neighborhood, characteristics and properties of the Milky Way Galaxy, interstellar medium, nebulae in the Milky Way.The product of the previously constructed 3D maps of stellar reddening (Gontcharov 2010) and R V variations (Gontcharov 2012) has allowed us to produce a 3D interstellar extinction map within the nearest kiloparsec from the Sun with a spatial resolution of 50 pc and an accuracy of 0.2 m . This map is compared with the 2D reddening map by Schlegel et al. (1998), the 3D extinction map at high latitudes by Jones et al. (2011), and the analytical extinction models by Arenou et al. (1992) and Gontcharov (2009). In all cases, we have found good agreement and show that there are no systematic errors in the new map everywhere except the direction toward the Galactic center. We have found that the map by Schlegel et al. (1998) reaches saturation near the Galactic equator at E (B−V ) > 0.8 m , has a zero-point error and systematic errors gradually increasing with reddening, and among the analytical models those that take into account the extinction in the Gould Belt are more accurate. Our extinction map shows that it is determined by reddening variations at low latitudes and R V variations at high ones. This naturally explains the contradictory data on the correlation or anticorrelation between reddening and R V available in the literature. There is a correlation in a thin layer near the Galactic equator, because both reddening and R V here increase toward the Galactic center. There is an anticorrelation outside this layer, because higher values of R V correspond to lower reddening at high *

lar neighborhood. The variations of kinematic parameters with age are considered for a sample of 15 402 thin-disk O-F stars with accurate α, δ, µ, and π > 3 mas from the Hipparcos catalogue and radial velocities from the PCRV catalogue. The ages have been calculated from the positions of the stars on the Hertzsprung-Russell diagram relative to the isochrones from the Padova database by taking into account the extinction from the previously constructed 3D analytical model and extinction coefficient R V from the 3D map of its variations. Smooth, mutually reconciled variations of the velocity dispersions σ(U), σ(V ), σ(W ), solar motion components U ⊙ , V ⊙ , W ⊙ , Ogorodnikov-Milne model parameters, Oort constants, and vertex deviation l xy consistent with all of the extraneous results for which the stellar ages were determined have been found. The velocity dispersion variations are well fitted by power laws the deviations from which are explained by the influence of predominantly radial stellar streams: Sirius, Hyades, α Cet/Wolf 630, and Hercules. The accuracy of determining the solar motion relative to the local standard of rest is shown to be fundamentally limited due to these variations of stellar kinematics. The deviations of our results from those of Dehnen and Binney (1998), the Geneva-Copenhagen survey of dwarfs, and the Besancon model of the Galaxy are explained by the use of PCRV radial velocities with corrected systematic errors. *