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Infrared dark clouds from the ISOGAL survey. Constraints on the interstellar extinction curve
Ganesh, S.; Teyssier, D.; Pérault, M. +1 more
The ISO galactic survey provides images of the inner disk in two broad filters (around 7 and 15 mu m) over some 15 square degrees, away from the brightest star forming regions. A multiresolution analysis of the images leads to a catalogue of infrared dark clouds, most of which are condensed cores of large molecular clouds, several kpc away from th…
Structure and Mass of a Young Globular Cluster in NGC 6946
Brodie, Jean P.; Elmegreen, Bruce G.; Hodge, Paul W. +3 more
Using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope, we have imaged a luminous young star cluster in the nearby spiral galaxy NGC 6946. Within a radius of 65 pc, the cluster has an absolute visual magnitude, MV=-13.2, comparable to the most luminous young ``super star clusters'' in the Antennae merger galaxy. UBV…
The MACHO Project: Microlensing Detection Efficiency
Alcock, C.; Allsman, R. A.; Alves, D. R. +21 more
The MACHO project is a search for dark matter in the form of massive compact halo objects (MACHOs). The project has photometrically monitored over forty million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud (SMC), and Galactic bulge in search of rare gravitational microlensing events caused by these otherwise invisible objects.…
Hubble Space Telescope Optical-Near-Infrared Colors of Nearby R1/4 and Exponential Bulges
Stiavelli, Massimo; de Zeeuw, P. Tim; Carollo, C. Marcella +2 more
We have analyzed V, H, and J Hubble Space Telescope (HST) images for a sample of early- to late-type spiral galaxies and have reported elsewhere the statistical frequency of R1/4-law and exponential bulges in our sample as a function of Hubble type and the frequency of occurrence and structural properties of the resolved central nuclei …
An XMM-Newton study of the X-ray binary MXB 1659-298 and the discovery of narrow X-ray absorption lines
Parmar, A. N.; Sidoli, L.; Oosterbroek, T. +2 more
We report the discovery of narrow X-ray absorption lines from the low-mass X-ray binary MXB 1659-298 during an XMM-Newton observation in 2001 February. The 7.1 hr orbital cycle is clearly evident with narrow X-ray eclipses preceded by intense dipping activity. A sinusoid-like OM B-band modulation with a peak-to-peak modulation of ~ 0.5 mag and a m…
Evidence for Dust Grain Growth in Young Circumstellar Disks
Throop, Henry B.; Bally, John; Esposito, Larry W. +1 more
Hundreds of circumstellar disks in the Orion nebula are being rapidly destroyed by the intense ultraviolet radiation produced by nearby bright stars. These young, million-year-old disks may not survive long enough to form planetary systems. Nevertheless, the first stage of planet formation-the growth of dust grains into larger particles-may have b…
Unusual Depletions toward the SMC Star SK 155-Differences in Dust Composition in the SMC Interstellar Medium?
York, Donald G.; Blades, J. Chris; Welty, Daniel E. +2 more
We report initial results from an analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph echelle spectra of interstellar absorption toward Sk 155, located in the ``wing'' region of the SMC. There are at least 12 Milky Way (disk and halo) and at least 25 SMC components discernible in the profiles of various neutral and singly ioniz…
The Proper Motion of the Globular Cluster NGC 6553 and of Bulge Stars with the Hubble Space Telescope
Zoccali, M.; Bica, E.; Barbuy, B. +2 more
WFPC2 images obtained with the Hubble Space Telescope (HST) 4.16 years apart have allowed us to measure the proper motion of the metal-rich globular cluster NGC 6553 with respect to the background bulge stars. With a space velocity of (Π, Θ, W)=(-3.5, 230, -3) km s-1, NGC 6553 follows the mean rotation of both disk and bulge stars at a …
Structure of Protostellar Collapse Candidate B335 Derived from Near-Infrared Extinction Maps
Wilner, David J.; Myers, Philip C.; Lada, Charles J. +3 more
We present a near-infrared extinction study of the dark globule B335, a protostellar collapse candidate, using data from the Hubble Space Telescope/Near Infrared Camera and Multi-Object Spectrometer and the W. M. Keck Observatory. These data allow a new quantitative test of the ``inside-out'' collapse model previously proposed to explain molecular…
Mid-Infrared observations of NGC 1068 with the Infrared Space Observatory
Le Floc'h, E.; Cesarsky, C.; Sauvage, M. +5 more
We report on Mid-Infrared (MIR) observations of the Seyfert 2 galaxy NGC 1068, obtained with ISOCAM in low-resolution spectro-imaging mode. The spatial resolution ( ~ 5 arcsec) allows us to disentangle the circumnuclear starburst regions from the emission of the active galactic nucleus (AGN). The global spatial distribution of the Unidentified Inf…