Search Publications
Dynamical mass estimates for two luminous young stellar clusters in Messier 83
Larsen, S. S.; Richtler, T.
Using new data from the UVES spectrograph on the ESO Very Large Telescope and archive images from the Hubble Space Telescope, we have measured projected velocity dispersions and structural parameters for two bright young star clusters in the nearby spiral galaxy
Effects of Metallicity on the Rotational Velocities of Massive Stars
Gies, Douglas R.; Penny, Laura R.; Sprague, Amanda J. +1 more
Recent theoretical predictions for low-metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and so should retain most of their angular momentum. Observations of both the Be/(B+Be) ratio and the blue-to-red supergiant ratio appear to have a metallicity dependence…
The strange physics of low frequency mirror mode turbulence in the high temperature plasma of the magnetosheath
Nakamura, R.; Constantinescu, O. D.; Treumann, R. A. +3 more
Mirror mode turbulence is the lowest frequency perpendicular magnetic excitation in magnetized plasma proposed already about half a century ago by Rudakov and Sagdeev (1958) and Chandrasekhar et al. (1958) from fluid theory. Its experimental verification required a relatively long time. It was early recognized that mirror modes for being excited r…
Visible spectral properties of asteroid 21 Lutetia, target of Rosetta Mission
Barbieri, C.; Lazzarin, M.; Marchi, S. +1 more
Rosetta spacecraft was successfully launched on March 2nd 2004 after its launch postponement in January 2003. Owing to this delay all the original targets, comet and asteroids, have been changed. In particular, on its 10 years journey to the new comet 67P/Churyumov-Gerasimenko, the spacecraft will pass close to the asteroid 21 Lutetia. In this pap…
The Galactic Inner Halo: Searching for White Dwarfs and Measuring the Fundamental Galactic Constant, Θ0/R0
Rich, R. Michael; Gibson, Brad K.; Stetson, Peter B. +9 more
We establish an extragalactic, zero-motion frame of reference within the deepest optical image of a globular star cluster, a Hubble Space Telescope (HST) 123 orbit exposure of M4 (GO 8679, Cycle 9). The line of sight beyond M4 (l,b=351deg,16deg) intersects the inner halo (spheroid) of our Galaxy at a tangent-point distance of…
An Erupting Classical Nova in a Globular Cluster of M87
Zurek, David R.; Lauer, Tod R.; Shara, Michael M. +2 more
Only one certain classical nova eruption has ever been detected inside a globular cluster-nova T Sco (observed in A.D. 1860) in M80. During a survey of M87 we have detected an erupting star coincident (to within 0.08 pixels) with a globular cluster of that giant elliptical galaxy. We are able to discount variables in the foreground or background o…
Determination of the 3D structure of an EUV-filament observed by SoHO/CDS, SoHO/SUMER and VTT/MSDP
Heinzel, P.; Anzer, U.; Schmieder, B. +1 more
Heinzel et al. (\cite{hein1}) found that filaments seem to be much more extended in EUV spectral lines than in Hα. In this paper we reconstruct the 3D structure of the extensions of the EUV-filament observed on 15 October 1999 by SoHO/CDS and SoHO/SUMER. Small Hα structures were observed by VTT/MSDP. We computed the bottom and top heights of the E…
Strong Gravitational Lens Candidates in the GOODS ACS Fields
Ferguson, H. C.; Moustakas, L. A.; Lucas, R. A. +3 more
We present results from a systematic search for strong gravitational lenses in the Great Observatories Origins Deep Survey (GOODS) Advanced Camera for Surveys (ACS) data. The search technique involves creating a sample of likely lensing galaxies, which we define as massive early-type galaxies in a redshift range 0.3<z<1.3. The target galaxie…
Chandra and XMM-Newton observations of NGC 4214: the hot interstellar medium and the luminosity function of dwarf starbursts
Heckman, Timothy M.; Stevens, Ian R.; Hartwell, Joanna M. +2 more
We present results from Chandra and XMM-Newton X-ray observations of NGC 4214, a nearby dwarf starburst galaxy containing several young regions of very active star-formation. Starburst regions are known to be associated with diffuse X-ray emission, and in this case the X-ray emission from the galaxy shows an interesting morphological structure wit…
Keck Spectroscopy of Red Giant Stars in the Vicinity of M31'S Massive Globular Cluster G1
Rich, R. Michael; Guhathakurta, Puragra; Reitzel, David B.
We present results from an ongoing Keck spectroscopic survey of red giant stars in a field located along the major axis of M31, ~34 kpc in projection from the nucleus and near the luminous globular cluster G1. We use multislit LRIS spectroscopy to measure the Ca II near-infrared triplet in 41 stars ranging in apparent magnitude from 20<I<22.…