A survey of cyclopropenylidene (C3H2) in galactic sources.

We report the results of an initial survey in a variety of Galactic sources for cyclopropenylidene (C3H2), the first interstellar hydrocarbon ring molecule. C3H2 is found to be very widespread throughout the Galaxy. This, together with its large dipole moment and many observable transitions, makes cyclopropenylidene a promising probe for physical conditions in the interstellar medium. The ortho 1(10)-1(01) transition at 18 GHz is detected in a variety of environments, including giant molecular clouds, diffuse clouds, cold dark clouds, the spiral arm clouds in the direction of distant continuum sources, and the envelope of the carbon star IRC + 10216. The 2(20)-2(11) para line at 21.6 GHz was surveyed in many sources having strong 1(10)-1(01) emission, and, when detected, it was always seen in absorption. A more limited survey of the ortho 2(12)-1(01) transition at 85.3 GHz has been conducted. In addition, the 2(11)-2(02) line of the para species at 46.8 GHz was detected in the dark clouds TMC-1 and L134N. Maps have been made of the clouds TMC-1, L134N, W51, and Orion, confirming that the C3H2 emission is extended in these objects. The data obtained thus far suggest that C3H2 is one of the more abundant organic constituents of the dense interstellar medium.

Identification of the interstellar cyanomethyl radical (CH2CN) in the molecular clouds TMC-1 and Sagittarius B2.

We report the astronomical identification of the cyanomethyl radical, CH2CN, the heaviest nonlinear molecular radical to be identified in interstellar clouds. The complex fine and hyperfine structures of the lowest rotational transitions at about 20.12 and 40.24 GHz are resolved in TMC-1, where the abundance appears to be about 5 x 10(-9) relative to that of H2. This is significantly greater than the observed abundance of CH3CN (methyl cyanide) in TMC-1. In Sgr B2 the hyperfine structure is blended in the higher frequency transitions at 40, 80, and 100 GHz, although the spin-rotation doubling is clearly evident. Preliminary searches in other sources indicate that the distribution of CH2CN is similar to that for such carbon chain species as HC3N or C4H.

A study of C3HD in cold interstellar clouds.

We have detected the 1(10)-1(01) transition of C3HD at 19.418 GHz at twelve positions in cold, dark clouds and resolved the D hyperfine components in two sources (L1498 and TMC-1C) well enough to derive values for the D quadrupole coupling constants. Simultaneous observations of C3H2 in each source yield relative integrated line intensities in the range 0.10-0.18, from which we derive relative [C3HD]/[C3H2] abundances in the range 0.05-0.15. These are among the highest deuteration ratios yet observed. Within the limits of the observational and modeling uncertainties it is possible to explain the derived [C3HD]/[C3H2] ratios by ion-molecule chemistry if [e-] approximately 3 x 10(-7).

Methanol in dark clouds.

We report observations, for the first time, of the 2(0) - 1(0)A+ and E, 2(-1) - 1(-1) E, and 1(0) - 0(0)A+ lines of methanol (CH3OH) in three dark cold clouds, TMC1, L134N, and B335. The CH3OH emission is extended in these clouds and shows a complex velocity structure. Clear indications of non LTE excitation are observed in TMC 1. Estimated column densities are a few 10(13) cm-2. Although less abundant than formaldehyde (H2CO), methanol is almost an order of magnitude more abundant than acetaldehyde (CH3CHO), in these clouds. Dimethyl ether was searched for in L134N, to an upper limit of 4 10(12) cm-2 (3 sigma). Implications for dark cloud excitation and chemistry are discussed. A new, more accurate, rest frequency 96741.39(0.01) MHz is determined for the 2(0) - 1(0) A+ E line of methanol.

Deuterium hyperfine structure in interstellar C3HD.

The deuterium nuclear quadrupole hyperfine structure of the transition 1(10)-1(01) of the ring molecule cyclopropenylidene-d1 (C3HD) has been observed in emission from interstellar molecular clouds. The narrowest linewidths (approximately 7 kHz) so far observed are in the cloud L1498. The derived D coupling constants Xzz = 186.9(1.4) kHz, eta=0.063(18) agree well with correlations based on other molecules.

Observations of OCS and a search for OC3S in the interstellar medium.

Observations of OCS and a search for OC3S are reported, with particular reference to cold dust clouds. OCS has been detected for the first time in dark clouds with a mean fractional abundance relative to hydrogen of approximately 3 x 10(-9); this is approximately 4 times greater than that observed for giant molecular clouds. This results is discussed in the context of molecule formation mechanisms. Observations of the J = 1 --> 0 transition of OCS indicate that this transition is amplifying the background continuum radiation in the direction of Sgr B2.

Detections of 13C-substituted C3H2 in astronomical sources.

We report observations of the 2(12)-1(01) rotational transition of the 13C isotopic species of cyclopropenylidene (C3H2) toward TMC-1, Sgr B2, and IRC +10216 using the laboratory rest frequencies which have recently become available. Our detections allow estimates to be made of the fractional abundance of the unsubstituted similar species in these sources. The fractional abundance relative to H2, f(C3H2), is 1-2 x 10(-8) in TMC-1, and this is similar to the abundance of HCN, one of the more abundant organic molecules in the interstellar medium. In IRC +10216 f(C3H2) is one order of magnitude greater than in TMC-1. The 12C species in Sgr B2 shows a self-absorbed profile and the relative abundance of C3H2 estimated to be about an order of magnitude less than in TMC-1.

The C3H2 2(20)-2(11) transition: absorption in cold dark clouds.

The first observations of the 2(20)-2(11) transition of cyclopropenylidene (C3H2) at 21.6 GHz are described. In all cases where it has been detected, the line appears in absorption, showing that this transition is "refrigerated" (i.e., Tex < 2.7 K) in cold dust clouds. These results are compared with those for the 1(10)-1(01) transition of C3H2, and the consequences for the excitation of C3H2 qualitatively discussed.

New interstellar masers in nonmetastable ammonia.

We report the astronomical detections of several ammonia inversion transitions involving nonmetastable levels with energies as high s 1090 K above the ground state. The (J, K) = (9, 6) inversion transition shows maser-like emission in the directions of W51, NGC 7538, W49, and DR 21(OH). The NH3 (6, 3) line exhibits similar characteristics in W51 but is seen in absorption in NGC 7538. These are the first definite detections of ammonia masers in space. The intensities and narrow line widths (0.5-1.5 km s-1) for the emission features are in contrast to the previously detected broad, weak, nonmetastable lines attributed to thermal emission in these sources. Temporal variability appears to be evident in the (9, 6) emission in W49 over a 4 month period. The highly excited (J, K) = (9, 6) and (6, 3) ammonia lines are found in regions containing compact H II regions and strong infrared sources with associated H2O and OH masers; i.e., in regions of active star formation.

Isolation and gas chromatographic characterization of some toxaphene components.

Column chromatography of technical toxaphene on activated alumina reproducibly yields eight major fractions from which 2,2,5-endo,6-exo,8,9,10-heptachlorobornane and 2,5,6-exo,8,8,9,10-heptachlorodihydrocamphene may be readily isolated by preparative gas--liquid chromatogrpahy. These and some other reported toxaphene components were characterized by gas--liquid chromatographic retentions relative to aldrin on packed columns of OV-101, OV-17, and QF-1, and on a capillary open-tubular column of OV-101. Structural assignments were revised for some components on the basis of retentions. The fractionation and isolation procedure may have general utility for separating toxaphene components, and the retention data form a convenient basis for component comparison.

Fine structural alterations of interphase nuclei of lymphocytes stimulated to grwoth activity in vitro.

This report describes fine structural changes of interphase nuclei of human peripheral blood lymphocytes stimulated to growth by short-term culture with phytohemagglutinin. Chromatin is found highly labile, its changes accompanying the sequential increases of RNA and DNA synthesis which are known to occur in lymphocyte cultures. In "resting" lymphocytes, abundant condensed chromatin appears as a network of large and small aggregates. Early in the response to phytohemagglutinin, small aggregates disappear during increase of diffuse chromatin regions. Small aggregates soon reappear, probably resulting from disaggregation of large masses of condensed chromatin. Loosened and highly dispersed forms then appear prior to the formation of prophase chromosomes. The loosened state is found by radioautography to be most active in DNA synthesis. Small nucleoli of resting lymphocytes have concentric agranular, fibrillar, and granular zones with small amounts of intranucleolar chromatin. Enlarging interphase nucleoli change chiefly (1) by increase in amount of intranucleolar chromatin and alteration of its state of aggregation and (2) by increase in granular components in close association with fibrillar components.