On the completeness of the lists of Compact Galaxy Groups

It is shown that the lists of Shakhbazian Compact Galaxy Groups (SCGGs) are not complete. The number of the detected groups in the strip between b = ±30° and b = ±20° is by four to five times smaller than expected. The most probable reason is that during the search for SCGGs it was hard to distinguish images of compact galaxies from that of stars on the POSS prints in dense areas of the sky at lower galactic latitudes. There is some deficit of the detected groups between 60° and 40° of the north galactic latitudes. The surface density of SCGGs in the southern galactic hemisphere between b = −50° and b = −30° is by about three times less than it is expected. Obviously, the southern sky has not been searched properly. The list of Hickson's groups is complete down to galactic latitude ±30°. However, some excess of HCGs is found in the southern hemisphere, where the surface density of the found groups is by about two times higher than that of in the northern hemisphere.     

Photometric catalogue of Shakhbazian compact groups of galaxies. IV.

The fourth part of the photometric catalogue of Shakhbazian compact groups of galaxies contains optical and geometrical properties of another 26 groups (Shkh 313, 314, 315, 316, 317, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, 332, 333, 334, 335, 336, 337, 357). As in the previous papers photometric data were obtained from the COSMOS/UKST catalogue of the Southern sky with δ ± +2°30'. The survey of compact galaxy groups by Shakhbazian, Petrosian, Baier, and Tiersch is a basis for studying physical properties of such groups.     

Photometric catalogue of Shakhbazian compact groups of galaxies. III.

The third part of the photometric catalogue of Shakhbazian compact groups of galaxies contains optical and geometrical properties of another 24 groups (Shkh 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 299, 300, 302, 303, 304, 305, 306, 307, 308, 309, 310, 311, 312). As in the first paper photometric data were obtained from the COSMOS/UKST catalogue of the Southern sky with δ ⩽ +2°30'. The survey of compact galaxy groups by Shakhbazian, Petrosian, Baier, and Tiersch is a basis for studying physical properties of such groups.     

Catalogue of Shakhbazian compact groups of galaxies. X

The tenth part of the catalogue of Shakhbazian groups contains the positions and references of all the galaxies of the following 35 groups (north of δ > +2°30'): Shkh 341, 342, 343, 344, 345, 346, 347, 348, 349, 350, 351, 352, 354, 355, 356, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 372, 373, 374, 375, 376, 377. For the estimation of the coordinates the Digitized Sky Survey was used.     

Catalogue of Shakhbazian compact groups of galaxies. VI.

The sixth part of the catalogue of Shakhbazian compact groups of galaxies contains the positions and references of all the galaxies of the following 48 groups (north of δ > +2°30''): Shkh 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107. For the estimation of the coordinates the Digitized Sky Survey was used.     

Catalogue of Shakhbazian compact groups of galaxies. IX

The nineth part of the catalogue of Shakhbazian groups contains the positions and references of all the galaxies of the following 48 groups (north of δ < +2°30'): Shkh 216, 217, 218, 219, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239, 240, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 253, 254, 255, 256, 257, 258, 259, 260, 328, 338, 339, 340, 340a. For the estimation of the coordinates the Digitized Sky Survey was used.     

Photometric catalogue of Shakhbazian compact groups of galaxies. II

The second part of the photometric catalogue of Shakhbazian compact groups of galaxies contains optical and geometrical properties of another 24 groups (Shkh 264, 265, 266, 267, 268, 269, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287). As in the first paper photometric data were obtained from the COSMOS/UKST catalogue of the Southern sky with δ ≤ +2°30′. The survey of compact galaxy groups by Shakhbazian, Petrosian, Baier, and Tiersch is a basis for studying dynamical processes in such groups.     

Photometric catalogue of Shakhbazian compact groups of galaxies. I

Compact groups of galaxies are fruitful laboratories to study such processes as dynamical friction, tidal interaction, collision, and galaxy mergers. The largest survey of compact galaxy groups is the one of Shakhbazian, Petrosian, Baier, Tiersch. A programme to evaluate photometrical properties of the galaxies in the Shakhbazian groups has been started using the COSMOS/UKST catalogue of the Southern sky with δ ≤ + 2°30′. About a quarter of the Shakhbazian groups lie south of this declination limit. A list of 24 groups (Shkh 21, 24, 27, 30, 32, 33, 35, 81, 82, 83, 140, 141, 143, 144, 145, 146, 147, 148, 151, 152, 154, 261, 262, 263) is our first result.     

Catalogue of Shakhbazian compact groups of galaxies. VII.

The seventh part of the catalogue of Shakhbazian groups contains the positions and references of all the galaxies of the following 48 groups (north of δ > +2°30′): Shkh 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 142, 149, 150, 153, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166. For the estimation of the coordinates the Digitized Sky Survey was used.     

Peculiarities of galactic rotation in the solar neighborhood from the data on red clump giants

The three-dimensional Ogorodnikov-Milne model was used to investigate the local velocity field on the basis of the tangential velocities of more than 53 000 red giants which were identified as most probable Red Clump members from the Tycho-2 catalog. Galactic rotation parameters were determined for two star groups at the galactic latitudes |b| < 30° and |b| ≥ 30°. The galactic rotation of the first star group was found to have some peculiarities characterized by the statistically significant parameters of contraction (K = ?6.3 ± 1.1 km s^?1 kpc^?1) and phase shift (? = 6.9° ± 0.6°) in the Ogorodnikov-Miln model. The vertex deflection and the semiaxes of peculiar velocity ellipsoid were determined for both star groups together with the components of the Sun’s motion with respect to these groups. The greatest distinction between two groups manifests itself in the vertex deflection, which is equal to 5.9° ± 0.7° at |b| < 30° and 0.1° ± 0.6° at |b| ≥ 30°.     

Catalogue of Shakhbazian compact groups of galaxies. V.

We present the position and references (if available) of all the galaxies of the Shakhbazian survey being the largest survey of compact galaxy groups. For the estimation of the coordinates the Digitized Sky Survey was used. This paper contains the data of 48 Shakhbazian groups north of δ > + 2deg;30' (Shkh 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 25, 26, 28, 29, 31, 34, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56).     

Chondrule thermal history from unequilibrated H chondrites: A transmission and analytical electron microscopy study

Abstract— Sixteen texturally different (porphyritic, barred, radial, cryptocrystalline) FeO‐rich chondrules from the unequilibrated ordinary chondrites Brownfield, Frontier Mountain (FRO) 90003 and FRO 90032 were characterized by optical and scanning electron microscopy and then thoroughly studied by transmission and analytical electron microscopy. Nanotextural and nanochemical data indicate similar thermal evolution for chondrules of the same textural groups; minor, yet meaningful differences occur among the different groups. Olivine is the earliest phase formed and crystallizes between 1500 and 1400 °C. Protoenstatite crystallizes at temperatures higher than 1350–1200 °C; it later inverts to clinoenstatite in the 1250–1200 °C range. Enstatite is surrounded by pigeonitic or (less frequently) augitic rims; the minimal crystallization temperature for the rims is 1000 °C; high pigeonite later inverts to low pigeonite, between 935 and 845 °C. The outer pigeonitic or augitic rims are constantly exsolved, producing sigmoidal augite or enstatite precipitates; sigmoidal precipitates record exsolution temperatures between 1000 and 640 °C. Cooling rate (determined using the speedometer based upon ortho‐clinoenstatite intergrowth) was in the order of 50–3000 °C/h at the clinoenstatite‐orthoenstatite transition temperature (close to 1250–1200 °C), but decreased to 5–10 °C/h or slower at the exsolution temperature (between 1000 and 650 °C), thus revealing nonlinear cooling paths. Nanoscale observations indicate that the individual chondrules formed and cooled separately from 1500 °C down to at least 650 °C. Accretion into chondritic parent body occurred at temperatures lower than 650 °C.     

The Ursa Major supercluster of galaxies: II. The structure and peculiar velocities

Kormendy’s relation (μ_e-logR _e) is used to investigate the structure of the compact Ursa Major supercluster of galaxies (11^h30^m+55°, cz=18 000 km s^?1); this relation allows the distances of early-type galaxies to be estimated. The relative distances of 13 clusters in the supercluster and their peculiar velocities are determined with a mean statistical accuracy of 6%. In general, the supercluster obeys the Hubble relation between radial velocity and distance. However, there is reason to suggest that the supercluster consists of two subsystems with mean radial velocities of 16 200 and 19 700 km s^?1. For a velocity dispersion in the subsystems of ～1100 km s^?1, the fact that each of them is gravitationally bound is not ruled out.     

New probable dwarf galaxies in northern groups of the Local Supercluster

We have searched for nearby dwarf galaxies in 27 northern groups with characteristic distances 8–15 Mpc based on the Second Palomar Sky Survey prints. In a total area of about 2000 square degrees, we have found 90 low-surface-brightness objects, more than 60% of which are absent from known catalogs and lists. We have classified most of these objects (～80%) as irregular dwarf systems. The first 21-cm line observations of the new objects with the 100-m Effelsberg radio telescope showed that the typical linear diameters (1–2 kpc), internal motions (～30 km s^?1), and hydrogen masses (～2 × 10⁷ M _⊙) of the new galaxies correspond to those expected for the dwarf population of nearby groups.     

Kinematics of the Gould Belt based on open clusters

We have redetermined the kinematic parameters of the Gould Belt using currently available data on the motion of nearby young (log t < 7.91) open clusters, OB associations, and moving stellar groups. Our modeling shows that the residual velocities reach their maximum values of ?4 km s^?1 for rotation (in the direction of Galactic rotation) and +4 km s^?1 for expansion at a distance from the kinematic center of ≈300 pc. We have taken the following parameters of the Gould Belt center: R ₀ = 150 pc and l ₀ = 128°. The whole structure is shown to move relative to the local standard of rest at a velocity of 10.7 ± 0.7 km s^?1 in the direction l = 274° ± 4° and b = ?1° ± 3°. Using the derived rotation velocity, we have estimated the virial mass of the Gould Belt to be 1.5 × 10⁶ M _⊙.     

Features of quasi-stationary precipitations according to the data obtained with the AVS-F instrument onboard the CORONAS-F satellite

In the absence of burst events, the typical count-rate temporal profile of the AVS-F instrument in the low-energy gamma-ray band has a single broad maximum in the geomagnetic-equator region at latitudes from ?30° to +40°). However, the so-called quasi-stationary precipitations, i.e., increases in the count rate by up to 15–30% with respect to the average level determined using polynomial fits, were observed in some equatorial regions at latitudes from ?25° to +30°. At least four (type I, II, III, and IV) groups of such events can be distinguished according to their temporal profiles. The temporal profiles of about 44% events show a rapid increase to the south from the geomagnetic equator and a gradual decrease in the northern direction. For about 21% of analyzed events, on the contrary, the count rate increases sharply to the north of the geomagnetic equator and decreases gradually to the south. About 4% of events have symmetric temporal profiles. Finally, another 4% of the detected events have the form of a significant (a factor of 1.3–1.8) increase in the count rate with a central maximum. Typical durations of precipitations are 7–10 min (the size of the precipitation region is 20°–35°). However, short events lasting for ～3 min (the size of the precipitation region is ～10°) were observed. The mean time interval in which the precipitations were observed in regions with dimensions of 10° in geographic latitude by 30° in geographic longitude was about 24 h (the maximum interval exceeded 8 days). The majority of precipitations were observed in a zone of width 40° centered at the geomagnetic equator. Quasi-stationary precipitations can be related to the precipitations of charged particles in certain regions of the Earth’s magnetosphere periodically crossed by the satellite.     

Asteroid spin‐axis longitudes from the Lowell Observatory database

By analyzing brightness variation with ecliptic longitude and using the Lowell Observatory photometric database, we estimate spin‐axis longitudes for more than 350,000 asteroids. Hitherto, spin‐axis longitude estimates have been made for fewer than 200 asteroids. We investigate longitude distributions in different dynamical groups and asteroid families. We show that asteroid spin‐axis longitudes are not isotropically distributed as previously considered. We find that the spin‐axis longitude distribution for Main Belt asteroids is clearly nonrandom, with an excess of longitudes from the interval 30°–110° and a paucity between 120° and 180°. The explanation of the nonisotropic distribution is unknown at this point. Further studies have to be conducted to determine if the shape of the distribution can be explained by observational bias, selection effects, a real physical process, or other mechanism.     

Radiants of the Leonids 1999 and 2001 Obtained by Lltv Systems Using Automatic Software Tools

Both amateur and professional meteor groups are more frequently using Low-Light level TV (LLTV) systems to record meteors. Double-station observations can yield orbit data. However, data analysis normally is still done by hand and thus time consuming. This paper addresses the question of whether available automated tools can be used to determine reasonably accurate orbits with minimum human intervention. The European Space Agency performed several observing campaigns to observe the Leonid meteor stream. In November 1999, the ESA meteor group was stationed at two locations in Southern Spain, in November 2001 at two stations close to Broome in North-Western Australia. Double-station observations with LLTV systems were conducted. The data was recorded on S-VHS video tapes. The tapes were processed using automatic detection software from which meteor heights, velocities and radiants were computed. This paper shows the results for the two maximum nights. The radiants determined in 1999 show a very large scatter due to unfortunate observing geometry and inaccurate position determination since one of the cameras was moving because of the wind. The 2001 data is excellent and the radiant was determined to be at RA = 153.96°±0.3° and Dec = 21.09°±0.2°. The error bars for individual meteor radiants are about 0.2° to 0.4°. This demonstrates that is indeed possible to determine good radiant positions using totally automated tools. Orbits, on the other hand, are not well defined due to the fact that the velocity of individual meteors shows large errors. Reasons for this are described.     

A search for possible stellar members of the α-spiral arm

The proper motions of groups of stars, selected according to magnitude and colour, near (l, b.)=(140°, 0°), were analysed in an attempt to identify possible members of the α-spiral arm defined by Verschuur fromHi observations. Other than late type giants the only objects whose distance corresponded to that of this arm were a small group of reddened early type stars.     

Morphology and Luminosity Segregations in Galaxy Groups

We study morphology and luminosity segregation of galaxies in groups. We analyze the two catalogs of (∼2×400) groups which have been identified in the Nearby Optical Galaxy sample, by means of hierarchical and percolation `friends-of-friends' methods. We find that earlier-type (brighter) galaxies are more clustered and lie closer to the group centers, both in position and in velocity, than later-type (fainter) galaxies. Spatial segregations are stronger than kinematical segregations. These effects are generally detected at the ≳3-sigma level, with the exception of morphological segregation in velocity, which is the weakest effect. Our main results are confirmed by the analysis of statistically more reliable groups (with at least five members), and are strengthened by the detection of segregation in both hierarchical and percolation catalogs. Luminosity segregation is shown to be independent of morphology segregation. Our conclusions agree with a continuum of segregation properties of galaxies in systems, from low-mass groups to massive clusters. This revised version was published online in July 2006 with corrections to the Cover Date.