Search Publications
Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group
Adelman, Saul J.; Soderblom, David R.; King, Jeremy R. +2 more
Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca II H and K emission measurements, literature-based abundance estimates, and updated photometry (including recent resolved measurements of close doubles), we revisit the Ursa Major moving group membership status of some 220 stars to produce a final clean…
The Globular Cluster System of NGC 1399. I. A Wide-Field Photometric Study
Geisler, D.; Dirsch, B.; Richtler, T. +3 more
We present a photometric investigation of the globular cluster population of NGC 1399, the central galaxy in the Fornax cluster, in Washington C and Kron R filters within a field of 36'×36', corresponding to about 200×200 kpc at the Fornax distance. This is the largest area around this galaxy ever studied with CCD photometry. The cluster system of…
OMC: An Optical Monitoring Camera for INTEGRAL. Instrument description and performance
Hanlon, L.; McBreen, B.; Mas-Hesse, J. M. +48 more
The Optical Monitoring Camera (OMC) will observe the optical emission from the prime targets of the gamma-ray instruments onboard the ESA mission INTEGRAL, with the support of the JEM-X monitor in the X-ray domain. This capability will provide invaluable diagnostic information on the nature and the physics of the sources over a broad wavelength ra…
The origin of crystalline silicates in the Herbig Be star HD 100546 and in comet Hale-Bopp
Waters, L. B. F. M.; Dominik, C.; de Koter, A. +1 more
We have investigated the spatial distribution, and the properties and chemical composition of the dust orbiting HD 100546. This system is remarkably different from other isolated Herbig Ae/Be stars in both the strength of the mid-IR excess and the composition of the circumstellar dust. To explain spectral features and the amount of mid-IR dust emi…
Kinematic Masses of Super-Star Clusters in M82 from High-Resolution Near-Infrared Spectroscopy
Graham, James R.; McCrady, Nate; Gilbert, Andrea M.
Using high-resolution (R~22,000) near-infrared (1.51-1.75 µm) spectra from Keck Observatory, we measure the kinematic masses of two super-star clusters in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives stellar velocity dispersions of σr=15.9+/-0.8 km s-1 for J0955505+694045 (MGG-…
Lyman break galaxies and the star formation rate of the Universe at z~ 6
Bunker, Andrew J.; McMahon, Richard G.; Stanway, Elizabeth R.
We determine the space density of UV-luminous starburst galaxies at z~ 6 using deep HST ACS SDSS-i' (F775W) and SDSS-z' (F850LP) and VLT ISAAC J and Ks band imaging of the Chandra Deep Field South. We find eight galaxies and one star with (i'-z') > 1.5 to a depth of z'AB= 25.6 (an 8σ detection in each of the 3 available AC…
Hot coronal loop oscillations observed with SUMER: Examples and statistics
Solanki, S. K.; Curdt, W.; Innes, D. E. +3 more
We give an extensive overview of Doppler shift oscillations in hot active region loops obtained with SUMER. The oscillations have been detected in loops sampled 50-100 arcsec off the limb of the Sun in ultraviolet lines, mainly Fe Xix and Fe Xxi, with formation temperature greater than 6 MK. The spectra were recorded along a 300 arcsec slit placed…
Chandra Observation of the Cooling Flow Cluster Abell 2052
Sarazin, Craig L.; McNamara, Brian R.; Blanton, Elizabeth L.
We present an analysis of the Chandra X-ray observation of A2052, including large-scale properties of the cluster as well as the central region, which includes the bright radio source 3C 317. We present temperature and abundance profiles using both projected and deprojected spectral analyses. The cluster shows the cooling flow signatures of excess…
The thermal radiation of the isolated neutron star RX J1856.5-3754 observed with Chandra and XMM-Newton
Haberl, F.; Burwitz, V.; Neuhäuser, R. +3 more
We present results of the analysis of data collected in 57-ks XMM-Newton and 505-ks Chandra observations of the nearby ( =~ 120 pc) isolated neutron star RX J1856.5-3754. We confirm most of the statements made by Burwitz et al. (\cite{Buretal01}) who discussed the original 55-ks Chandra data. Detailed spectral analysis of the combined X-ray and op…
Grain growth in the inner regions of Herbig Ae/Be star disks
Waters, L. B. F. M.; Dominik, C.; van Boekel, R. +4 more
We present new mid-infrared spectroscopy of the emission from warm circumstellar dust grains in Herbig Ae/Be stars. Our survey significantly extends the sample that was studied by Bouwman et al. (2001). We find a correlation between the strength of the silicate feature and its shape. We interpret this as evidence for the removal of small (0.1 mu m…