[en] High-resolution (2.4-arcsec) CO observations of the interacting system Arp 299 (Mrk 171: IC 694 and NGC 3690) reveal major gas condensations at the nuclei of both galaxies and in the disk overlap region. The 0.9 x 10 to the 9th solar masses of H2 at the nucleus of NGC 3690 extends to radii of 310 pc and probably sustains a starburst. A compact source (radius not greater than 250 pc) of mass 3.9 x 10 to the 9th solar masses is found at the nucleus of IC 694; this galaxy may harbor an AGN. At least three discrete subcondensations, probably active star-forming knots, are detected in the 1800 x 640 pc overlap region. 24 refs

[en] Advantages of the G-banding technique for chromosomal analysis are discussed and the technique is described. A table is presented to show chromosomal counts on radioinduced osteosarcomas in ²²⁶Ra- and ⁹⁰Sr-treated beagles and representative photographs of banded chromosomes are shown

[en] A set of 1.4-mm continuum measurements for a sample of 15 Galactic and extragalactic sources obtained with a millimeter-wave interferometer are presented. Maps at 3 arcsec resolution reveal compact dust emission regions in L1551 IRS 5, HH 7-11, NGC 7538 IRS 1, DR 21(OH) and Arp 220. In Arp 220 about 50 percent of the total 1.4-mm flux originates from a compact source less than 650 pc in radius centered on the NIR nucleus. The mass of interstellar matter in the central source of Arp 220 is approximately 3 X 10 to the 9th solar masses. Comparison of the 1.4 and 2.7-mm dust emission in 10 Galactic sources indicates a spectra index of 3.0 + or - 0.2 for the frequency dependence of the observed small-scale flux. 15 refs

[en] High-resolution (3 arcsec) aperture synthesis maps in the J = 2 to 1 transition of CO-18 have been obtained for the star formation regions DR 21(OH) and L1551 IRS 5. Two compact sources, separated by 7 arcsec, have been discovered at the centers of H2O maser activity associated with DR 21(OH). Mass estimates from the 1.4 mm continuum and CO-18 line emission are similar to the 110 solar masses required for a bound system with the observed 4 km/s radial velocity difference, suggesting that a massive multiple star system is forming. The CO-18 emission from L1551 IRS 5 is extended in an elongated structure of radius 700 AU and mass of 0.1 solar masses. 17 refs

[en] Five bright-rimmed molecular clouds, NGC 1977, IC 1396, IC 1848 A, B35, and NGC 7822, have been mapped with 30'' resolution in the J = 2--1 lines of ¹²co. For the first three, ¹³CO maps have also been made. The spatial distributions of temperature, density, and molecular abundance in these clouds have been determined, particularly in the vicinity of the rims. In general, the gas densities increase close to the rims, but temperature enhancements occur over comparatively extended regions. Near the rims the gas kinematics is varied: velocity gradients are observed in several regions, and in IC 1396 line broadening is distinguishable. A detailed study of the excitation of ¹³CO demonstrates that near the well-resolved rim in NGC 1977 where C I and carbon recombination lines have been observed, there is a definite decline in the CO abundance. These molecular clouds span a variety of stages of star formation, but in none does the interaction with the adjacent H II region appear to have substantially affected the course of the star-forming history of the cloud

[en] The authors observed ¹²CO (J=2-1) emission in the direction of several galactic HII regions. At a frequency of 230 GHz the angular resolution was 30 arcsec and the velocity resolutions were 0.3 and 1.3 km s^-1. The cores of 16 molecular clouds associated mainly with compact and subcompact HII regions were observed: S88, S106, S157, S158 (NGC 7538), S159, S187, S228, S255 (IC 2162), S269, ON-1, G45.5-0.1, W1 (center), W58 (K3-50), Cep A and Mon R2. Observations of all sources were in a cross pattern of at least five points. Four sources - Cep A, Mon R2, S158 and W58 - were mapped in more detail. (Auth.)

[en] In this paper, we study the determinants of starless core temperatures in the Perseus molecular cloud. We use NH₃ (1,1) and (2,2) observations to derive core temperatures (T _kin) and data from the COMPLETE Survey of Star-Forming Regions and the c2d Spitzer Legacy Survey for observations of the other core and molecular cloud properties. The kinetic temperature distribution probed by NH₃ is in the fairly narrow range of ∼ 9-15 K. We find that cores within the clusters IC348 and NGC1333 are significantly warmer than ^fieldstarless cores, and T _kin is higher within regions of larger extinction-derived column density. Starless cores in the field are warmer when they are closer to Class 0/I protostars, but this effect is not seen for those cores in clusters. For field starless cores, T _kin is higher in regions in which the ¹³CO line width and the 1.1 mm flux from the core are larger, and T _kin is lower when the the peak column density within the core and average volume density of the core are larger. There is no correlation between T _kin and ¹³CO line width, 1.1 mm flux, density, or peak column density for those cores in clusters. The temperature of the cloud material along the line of sight to the core, as measured by CO or far-infrared emission from dust, is positively correlated with core temperature when considering the collection of cores in the field and in clusters, but this effect is not apparent when the two subsamples of cores are considered separately.

[en] We present new near-infrared interferometric data from the CHARA array and the Keck Interferometer on the circumstellar disk of the young star, TW Hya, a proposed 'transition disk'. We use these data, as well as previously published, spatially resolved data at 10 μm and 7 mm, to constrain disk models based on a standard flared disk structure. We find that we can match the interferometry data sets and the overall spectral energy distribution with a three-component model, which combines elements at spatial scales proposed by previous studies: optically thin, emission nearest the star, an inner optically thick ring of emission at roughly 0.5 AU followed by an opacity gap and, finally, an outer optically thick disk starting at ∼4 AU. The model demonstrates that the constraints imposed by the spatially resolved data can be met with a physically plausible disk but this requires a disk containing not only an inner gap in the optically thick disk as previously suggested, but also a gap between the inner and outer optically thick disks. Our model is consistent with the suggestion by Calvet et al. of a planet with an orbital radius of a few AU. We discuss the implications of an opacity gap within the optically thick disk.