Search Publications
Steady Flows Detected in Extreme-Ultraviolet Loops
Golub, Leon; Winebarger, Amy R.; Warren, Harry +2 more
Recent Transition Region and Coronal Explorer (TRACE) observations have detected a class of active region loops whose physical properties are inconsistent with previous hydrostatic loop models. In this Letter we present the first co-aligned TRACE and the Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of these loops. Althou…
Crystalline silicate dust around evolved stars. III. A correlations study of crystalline silicate features
Waters, L. B. F. M.; Tielens, A. G. G. M.; Koike, C. +2 more
We have carried out a quantitative trend analysis of the crystalline silicates observed in the ISO spectra of a sample of 14 stars with different evolutionary backgrounds. We have modeled the spectra using a simple dust radiative transfer model and have correlated the results with other known parameters. We confirm the abundance difference of the …
Correlation of the Coronal Mass Ejection Productivity of Solar Active Regions with Measures of Their Global Nonpotentiality from Vector Magnetograms: Baseline Results
Falconer, D. A.; Moore, R. L.; Gary, G. A.
From conventional magnetograms and chromospheric and coronal images, it is known qualitatively that the fastest coronal mass ejections (CMEs) are magnetic explosions from sunspot active regions in which the magnetic field is globally strongly sheared and twisted from its minimum-energy potential configuration. In this paper, we present measurement…
The mass function of the Arches cluster from Gemini adaptive optics data
Brandner, W.; Grebel, E. K.; Stolte, A. +1 more
We have analysed high resolution adaptive optics (AO) science demonstration data of the young, massive stellar cluster Arches near the Galactic Center, obtained with the Gemini North telescope in combination with the University of Hawai'i AO system Hokupa'a. The AO H and K' photometry is calibrated using HST/NICMOS observations in the equivalent f…
XMM-Newton discovery of a sharp spectral feature at ~ 7 keV in the narrow-line Seyfert 1 galaxy 1H 0707 - 49
Sunyaev, R.; Brandt, W. N.; Iwasawa, K. +6 more
We report the first detection of a sharp spectral feature in a narrow-line Seyfert 1 galaxy. Using XMM-Newton we have observed 1H 0707-495 and find a drop in flux by a factor of more than 2 at a rest-frame energy of ~7 keV without any detectable narrow Fe Kα line emission. The energy of this feature suggests a connection with the neutral iron K ph…
Star formation and dust extinction in nearby star-forming and starburst galaxies
Buat, V.; Boselli, A.; Gavazzi, G. +1 more
We study the star formation rate and dust extinction properties of a sample of nearby star-forming galaxies as derived from Hα and UV ( ~ 2000 Å) observations and we compare them to those of a sample of starburst galaxies. The dust extinction in Hα is estimated from the Balmer decrement and the extinction in UV using the FIR to UV flux ratio or th…
Extragalactic globular clusters in the near-infrared. II. The globular clusters systems of NGC 3115 and NGC 4365
Minniti, D.; Hilker, M.; Kissler-Patig, M. +3 more
We combine near-infrared photometry obtained with the VLT/ISAAC instrument and archival HST/WFPC2 optical images to determine VIK magnitudes and colours of globular clusters in two early-type galaxies, NGC 3115 and NGC 4365. The combination of near-IR and optical photometry provides a way to lift the age-metallicity degeneracy. For NGC 3115, the g…
The FIR/Radio correlation of high redshift galaxies in the region of the HDF-N
Garrett, M. A.
The correlation between the far-infrared (FIR) and radio emission is well established for nearby star forming galaxies. Many applications, in particular the radio-to-submm spectral index redshift indicator, tacitly assume that the relation holds well beyond our local neighbourhood, to systems located at cosmological distances. In order to test thi…
Spatiotemporal variability and propagation of equatorial noise observed by Cluster
Gurnett, D. A.; Pickett, J. S.; Maksimovic, M. +2 more
We report a multipoint case study of the electromagnetic equatorial noise observed by the Cluster project. High-resolution data were measured in three close points in space located in the morning sector of the outer plasmasphere. We demonstrate a narrow latitudinal extent of the emissions with a typical width of 2°, centered near the minimum-B equ…
A High Angular Resolution Multiplicity Survey of the Open Clusters α Persei and Praesepe
Ghez, A. M.; Matthews, K.; Patience, J. +1 more
Two hundred forty-two members of the Praesepe and α Persei clusters have been surveyed with high angular resolution 2.2 µm speckle imaging on the 3 m Infrared Telescope Facility, the 5 m Hale, and the 10 m Keck telescopes, along with direct imaging using the near-infrared camera (NICMOS) aboard the Hubble Space Telescope. The observed stars …