Electroantennogram responses of male Sphinx perelegans hawkmoths to floral and ‘green-leaf volatiles’

Electroantennograms (EAGs) from field-collected male Sphinx perelegans hawkmoths were recorded in response to 10 individual floral scent compounds identified from Clarkia breweri (Onagraceae), 21 additional volatiles characteristic of other night-blooming flowers, and eight ‘green leaf’ volatiles. Measurable EAG responses were elicited to all compounds tested, but the most effective antennal stimulants were benzyl acetate, linalool, methyl salicylate and trans-2-hexenal. Mean, pooled EAGs to oxygenated terpenoids, aromatic esters and fatty acid derivatives were larger in magnitude than those in response to aromatic aldehydes/alcohols, monoterpenes and nitrogen-bearing compounds. The rank order of male S. perelegans' EAGs did not differ significantly from that of previously recorded responses of male Hyles lineata to the same scent compounds, and EAG magnitudes were generally larger for S. perelegans than for H. lineata. Both hawkmoth species are shown to have broad olfactory receptivities and could potentially respond to a wide array of plant volatiles as floral attractants.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42717/1/10667_2004_Article_158733.pd

Hubble Space Telescope imaging of η Carinae

We present new high spatial resolution observations of the material around η Carinae obtained with the Hubble Space Telescope Wide Field/Planetary Camera. The star η Carinae is one of the most massive and luminous stars in our Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0".2 (~10^(16)cm) scales. An extension to the northeast of the star {NN/NS using Walborn's [ApJL, 204, L17 ( 1976)] nomenclature} appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a "cap" of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow

Planetary camera observations of the central parsec of M32

Analysis of V band HST Planetary Camera images of the elliptical galaxy M32 shows that its nucleus is extremely dense and remains unresolved at even the HST diffraction limit. A combined approach of image deconvolution and model fitting is used to investigate the starlight distribution into limiting radii of 0".04 (0.14 pc at 700 kpc). The logarithmic slope of the brightness profile smoothly flattens from y= -1.2 at 3.4 pc to y= -0.5 at 0.34 pc; interior to this radius the profile is equally consistent with a singular µ(r)∝ r,^(-1/2) cusp or a small nonisothermal core with r_c<0.37 pc. The isophotes maintain constant ellipticity into tlle center, and there is no evidence for a central point source, disk, dust, or any other substructures. The cusp model implies central mass densities p_0 > 3 X 10^7 M_☉ pc^(-3) at the resolution limit and is consistent with a central M_• = 3 X 10^6 M_☉ black hole; the core model implies p_0≈4 X 10^6 M_☉ pc^(-3). From the viewpoint of long-term stability, we argue that a starlight cusp surrounding a central black hole is the more plausible interpretation of the observations. A core at the implied density and size without a black hole has a relaxation time of only ~7 X 10^7 yr and a short stellar oollision timescale implying wholesale stellar merging over the age of the universe. The core would be strongly vulnerable to collapse and concomitant runaway stellar merging. Collapse may lead to formation of a massive black hole in any case if it cannot be reversed by formation of a binary from high-mass merger products. Regardless of the ultimate fate of the core, however, structural evolution of the core will always be accompanied by strong evolution of the core population-the constant isophote shape and absence of a central color gradient appear to show that such evolution has not occurred. In contrast, the high velocities around a black hole imply long relaxation and stellar collision times for the cusp population compared to the age of the universe