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Hubble Space Telescope imaging of globular cluster candidates in low surface brightness dwarf galaxies
Sharina, M. E.; Makarov, D. I.; Puzia, T. H.
Fifty-seven nearby low surface brightness dwarf galaxies (-10⪆ MV⪆ -16) were searched for globular cluster candidates (GCCs) using Hubble Space Telescope WFPC2 imaging in V and I. The sample consists of 18 dwarf spheroidal (dSph), 36 irregular (dIrr), and 3 "transition" type (dIrr/dSph) galaxies with angular sizes less than 3.7 kpc situ…
The DEEP2 Galaxy Redshift Survey: Discovery of Luminous, Metal-poor Star-forming Galaxies at Redshifts z ~ 0.7
Hoyos, C.; Koo, D. C.; Willmer, C. N. A. +2 more
We have discovered a sample of 17 metal-poor, yet luminous, star-forming galaxies at redshifts z~0.7. They were selected from the initial phase of the DEEP2 survey of 3900 galaxies and the Team Keck Redshift Survey (TKRS) of 1536 galaxies as those showing the temperature-sensitive [O III] λ4363 auroral line. These rare galaxies have blue luminosit…
XMM-Newton X-ray spectroscopy of the high-mass X-ray binary 4U 1700-37 at low flux
Kaper, L.; van der Klis, M.; Barr, P. +4 more
We present results of a monitoring campaign of the high-mass X-ray binary system
X-Ray/Ultraviolet Observing Campaign of the Markarian 279 Active Galactic Nucleus Outflow: A Global-Fitting Analysis of the Ultraviolet Absorption
Laor, Ari; Scott, Jennifer E.; Kriss, Gerard A. +12 more
We present an analysis of the intrinsic UV absorption in the Seyfert 1 galaxy Mrk 279 based on simultaneous long observations with the Hubble Space Telescope (41 ks) and the Far Ultraviolet Spectroscopic Explorer (91 ks). To extract the line-of-sight covering factors and ionic column densities, we separately fit two groups of absorption lines: the…
Martian variable features: New insight from the Mars Express Orbiter and the Mars Exploration Rover Spirit
Greeley, Ronald; Whelley, Patrick L.; Neakrase, Lynn D. V. +12 more
Linear, low-albedo patterns (termed dark wind streaks) formed on the floor of Gusev crater between September 2003 and February 2004, as seen on High Resolution Stereo Camera images taken on board the Mars Express Orbiter. Pancam images from the Mars Exploration Rover Spirit show that the rover crossed a dark streak during its traverse to Bonnevill…
The composition and size distribution of the dust in the coma of Comet Hale Bopp
Waters, L. B. F. M.; Dominik, C.; de Koter, A. +2 more
We discuss the composition and size distribution of the dust in the coma of Comet Hale-Bopp. We do this using a model fit for the infrared emission measured by the Infrared Space Observatory (ISO) and the measured degree of linear polarization of scattered light at various phase angles and wavelengths. The effects of particle shape on the modeled …
Strong dust processing in circumstellar discs around 6 RV Tauri stars. Are dusty RV Tauri stars all binaries?
Waters, L. B. F. M.; Dominik, C.; Dejonghe, H. +2 more
We present extended Spectral Energy Distributions (SEDs) of seven classical RV Tauri stars, using newly obtained submillimetre continuum measurements and Geneva optical photometry supplemented with literature data. The broad-band SEDs show a large IR excess with a black-body slope at long wavelengths in six of the seven stars, R Sct being the noti…
On the Stellar Populations in NGC 185 and NGC 205 and the Nuclear Star Cluster in NGC 205 from Hubble Space Telescope Observations
Martínez-Delgado, D.; Butler, D. J.
We present the first detailed analysis of resolved stellar populations in the dwarf galaxies NGC 185 and NGC 205 based on archival V- and I-band WFPC2 pointings. For NGC 185 we deduce from the brightest main-sequence and blue-loop stars that star formation was probably still active about 4×108 yr ago and have three key abundance-related…
The broad-band spectrum of the persistent emission from SGR 1806-20
Hurley, K.; Sunyaev, R.; Revnivtsev, M. +3 more
We present the results of an analysis of the quiescent X-ray emission from the Soft Gamma-Ray Repeater SGR 1806-20, taken during an INTEGRAL ultra-deep survey of the Galactic center region in Aug.-Sep. 2003. The total effective exposure time spent on the source by the IBIS telescope during these observations was 1.6 million seconds. Combining the …
Supernova Explosions, 511 keV Photons, Gamma Ray Bursts and Mirror Matter
Foot, R.; Silagadze, Z. K.
There are three astroparticle physics puzzles which fire the imagination: the origin of the "Great Positron Producer" in the galactic bulge, the nature of the gamma-ray bursts central engine and the mechanism of supernova explosions. We show that the mirror matter model has the potential to solve all three of these puzzles in one beautifully simpl…