Search Publications
The Spatially Resolved Mass Function of the Globular Cluster M22
Albrow, Michael D.; Sahu, Kailash C.; De Marchi, Guido
Hubble Space Telescope imaging of M22 has allowed, for the first time, a detailed and uniform mapping of mass segregation in a globular cluster. Luminosity and mass functions from the turnoff down to the mid to lower main sequence are presented for M22 in annular bins from the center of the cluster out to five core radii. Within the core, a signif…
Proper Motions in the Knotty, Bipolar Jet in Henize 2-90
Sahai, R.; Brandner, W.; Grebel, E. K. +4 more
Using second-epoch Hubble Space Telescope imaging of the unusual, bipolar jet source He 2-90, we have discovered proper motions of 0.03" yr-1 in the jet knots. Combining the proper motion with the knots' radial velocity measured from ground-based long-slit data, we find that the jet speed is roughly 150-360 km s-1, the source…
MERLIN Radio Detection of an Interaction Zone within a Binary Orion Proplyd System
O'Dell, C. R.; Henney, W. J.; Meaburn, J. +3 more
Presented here are high angular resolution MERLIN 5 GHz (6 cm) continuum observations of the binary proplyd system LV 1 in the Orion nebula, which consists of proplyd 168-326 SE and its binary proplyd companion 168-326 NW (separation 0.4"). Accurate astrometric alignment allows a detailed comparison between these data and published Hubble Space Te…
Is a Minor Merger Driving the Nuclear Activity in the Seyfert 2 Galaxy NGC 2110?
Arribas, Santiago; Heckman, Timothy; Pérez, Enrique +1 more
We report on a detailed morphological and kinematic study of the isolated nonbarred nearby Seyfert 2 galaxy NGC 2110. We combine integral field optical spectroscopy with long-slit and WFPC2 imaging available in the Hubble Space Telescope archive to investigate the fueling mechanism in this galaxy. Previous work (Wilson & Baldwin) concluded tha…
Ultraviolet Imaging Polarimetry of the Seyfert 2 Galaxy Markarian 3
Cohen, Ross D.; Antonucci, Robert; Kishimoto, Makoto +3 more
We present ultraviolet (UV) imaging polarimetry data of the Seyfert 2 galaxy Mrk 3, taken by the Hubble Space Telescope. The polarized flux is found to be extended to ~1 kpc from the nucleus, and the position angles of polarization are centrosymmetric, confirming that the polarization is caused by scattering. We determine the location of the hidde…
The Extraordinary Cataclysmic Binary RU Pegasi: The Hottest White Dwarf in a Dwarf Nova?
Sion, Edward M.; Urban, Joel
We present the results of the first multicomponent synthetic spectral analysis of International Ultraviolet Explorer (IUE) archival spectra of the long-period dwarf nova RU Peg during quiescence. The best-fit, high-gravity, solar composition photosphere models yield Teff=50,000-53,000 K with scale factor distances of 250 pc. Optically t…
LOTIS, Super-LOTIS, Sloan Digital Sky Survey, and Tautenburg Observations of GRB 010921
Cline, T.; Hurley, K.; Brinkmann, J. +36 more
We present multi-instrument optical observations of the High Energy Transient Explorer (HETE-2) and Interplanetary Network error box of GRB 010921. This event was the first gamma-ray burst (GRB) partly localized by HETE-2 that has resulted in the detection of an optical afterglow. In this Letter, we report the earliest known observations of the GR…
The Helium Focusing Cone of the Local Interstellar Medium Close to the Sun
Romoli, M.; Raymond, J. C.; Bertaux, J. L. +13 more
The Solar and Heliospheric Observatory (SOHO) Ultraviolet Coronagraph Spectrometer is used to observe the interplanetary He focusing cone within 1 AU. Taken over 2 yr and from differing orbit positions, the series of observations includes measurements of He I 584 Å and Lyβ intensities. The cone itself is spatially well defined, and the He I intens…
POX 186: A Dwarf Galaxy in the Process of Formation?
Vacca, William D.; Corbin, Michael R.
We present deep U-, V-, and I-band images of the ``ultracompact'' blue dwarf galaxy POX 186 obtained with the Planetary Camera 2 of the Hubble Space Telescope. We have also obtained a near-ultraviolet spectrum of the object with the Space Telescope Imaging Spectrograph and combine this with a new ground-based optical spectrum. The images confirm t…
Tomographic Separation of Composite Spectra. IX. The Massive Close Binary HD 115071
Gies, Douglas R.; Stickland, D. J.; Lloyd, C. +2 more
We present the first orbital elements for the massive close binary HD 115071, a double-lined spectroscopic binary in a circular orbit with a period of 2.73135+/-0.00003 days. The orbital semiamplitudes indicate a mass ratio of M2/M1=0.58+/-0.02, and yet the stars have similar luminosities. We used a Doppler tomography algorit…