James M De Buizer

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When viewed in optical starlight scattered by dust, the nearly edge-on debris disk surrounding the A5V star beta Pictoris (distance 19.3 pc; ref. 1) extends farther than 1,450 au from the star. Its large-scale complexity has been well characterized, but the detailed structure of the disk's central approximately 200-au region has remained elusive. This(More)
We present the mass function (MF) of the Arches cluster obtained from ground-based adaptive optics data in comparison with results derived from HST/NICMOS data. A MF slope of Γ = −0.8 ± 0.2 is obtained. Both datasets reveal a strong radial variation in the MF, with a flat slope in the cluster center, which increases with increasing radius.
When viewed in optical starlight scattered by dust, the nearly edge-on debris disk surrounding the A5V star b Pictoris (distance 19.3 pc; ref. 1) extends farther than 1,450 AU from the star 2. Its large-scale complexity has been well characterized, but the detailed structure of the disk's central ,200-AU region has remained elusive. This region is of(More)
Context. Methanol masers are often found in linear distributions, and it has been hypothesized that these masers are tracing circumstellar accretion disks around young massive stars. However, recent observations in H2 emission have shown what appear to be outflows at similar angles to the maser distribution angles, not perpendicular as expected in the(More)
We present spatially resolved mid-infrared spectroscopy of the class I/flat-spectrum protostellar binary system SVS20 in the Serpens cloud core. The spectra were obtained with the mid-infrared instrument T-ReCS on Gemini-South. SVS20-South, the more luminous of the two sources, exhibits a mid-infrared emission spectrum peaking near 11.3 µm, while(More)
A brief review is given of the basic observed features of the stellar IMF, and also of some of the theoretical ideas and simulations that may help to explain these features. The characteristic stellar mass of order one solar mass may derive from the typical masses of the observed star-forming clumps in molecular clouds, and the typical clump mass may in(More)
Using the Thermal-Region Camera and Spectrograph (T-ReCS) attached to the Gemini South 8m telescope, we have detected and resolved 10µm emission at the position of the inner equatorial ring (ER) of supernova SN 1987A at day 6067. " Hot spots " similar to those found in the optical and near-IR are clearly present. The morphology of the 10µm emission is(More)
We present subarcsecond resolution mid infrared images of NGC 4151 at 10.8µm and 18.2µm. These images were taken with the University of Florida mid-IR camera/spectrometer OSCIR at the Gemini North 8 m telescope. We resolve emission at both 10.8µm and 18.2µm extending ∼ 3.5 ′′ across at a P.A. of ∼ 60 •. This coincides with the the narrow line region of NGC(More)
We present high-resolution (<0. ′′ 5) mid-infrared Keck II images of individual sources in the central region of NGC 6334 I. We compare these images to images at a variety of other wavelengths from the near infrared to cm radio continuum and speculate on the nature of the NGC 6334 I sources. We assert that the cometary shape of the UCHII region here, NGC(More)