Search Publications
Evidence for a magnetic neutron star in high-mass X-ray binary 4U 2206+54 with INTEGRAL/IBIS observations
Wang, Wei
The hard X-ray source 4U 2206+54 is a peculiar high-mass X-ray binary with a main-sequence donor star. Recent X-ray observations suggested that the compact object in 4U 2206+54 may be a neutron star. The X-ray emission comes from the accretion of stellar winds from the massive donor star, and variability of its luminosity may be due to changes in …
Color Bimodality in M87 Globular Clusters
Zepf, Stephen E.; Lauer, Tod R.; Waters, Christopher Z. +1 more
We present an analysis of a 50 orbit Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) observation of the M87 globular cluster system. We use the extraordinary depth of this data set to test whether the colors and magnitudes show evidence for a mass-metallicity relation in globular cluster populations. We find only a weak or absent re…
High-resolution Atlases of Mimas, Tethys, and Iapetus derived from Cassini-ISS images
Scholten, F.; Matz, K. -D.; Neukum, G. +8 more
The Cassini Imaging Science Subsystem (ISS) acquired 282, 258, and 513 high-resolution images (<800 m/pixel) of Mimas, Tethys, and Iapetus, respectively, during two close flyby of Tethys and Iapetus and eight non-targeted flybys between 2004 and 2007. We combined these images with lower-resolution Cassini images and others taken by Voyager came…
Stellar population of the irregular galaxy IC 10
Tikhonov, N. A.; Galazutdinova, O. A.
Based on our observations with the 6-m BTA telescope at the Special Astrophysical Observatory, the Russian Academy of Sciences, and archival Hubble Space Telescope images, we have performed stellar photometry for several regions of the irregular galaxy IC 10, a member of the Local Group. Distance moduli with a median value of m - M = 24.47, D = 78…
The expected detection of dust emission from high-redshift Lyman α galaxies
Finkelstein, Steven L.; Hathi, Nimish P.; Pirzkal, Norbert +2 more
Recent results have shown that a substantial fraction of high-redshift Lyman α (Lyα) galaxies contain considerable amounts of dust. This implies that Lyα galaxies are not primordial, as has been thought in the past. However, this dust has not been directly detected in emission; rather it has been inferred based on extinction estimates from rest-fr…
Long-term chromospheric activity of non-eclipsing RS CVn-type stars
Buccino, A. P.; Mauas, P. J. D.
Context: The IUE database provides several UV high and low-resolution spectra of RS CVn-type stars from 1978 to 1996. In particular, many of these stars were monitored continuously during several seasons by IUE.
Aims: Our main purpose is to study the short and long-term chromospheric activity of the RS CVn systems most observed by IUE: HD 22 4…
Discovery of Fog at the South Pole of Titan
Brown, M. E.; Chen, C.; Ádámkovics, M. +1 more
While Saturn's moon Titan appears to support an active methane hydrological cycle, no direct evidence for surface-atmosphere exchange has yet appeared. The indirect evidence, while compelling, could be misleading. It is possible, for example, that the identified lake features could be filled with ethane, an involatile long-term residue of atmosphe…
Star clusters in the interacting galaxy system Arp 284
Peterson, Bradley W.; Struck, Curtis; Smith, Beverly J. +1 more
We present results from a study of protoglobular cluster candidates in the interacting galaxy system Arp 284 (NGC 7714/5) using data from the Hubble Space Telescope (HST). Previous studies of the Antennae and M51 have suggested that the majority of young massive star clusters dissolve within 20 Myr due to mass loss. We use the evolutionary synthes…
Cluster survey of the mid-altitude cusp - Part 2: Large-scale morphology
Escoubet, C. P.; Pitout, F.; Dandouras, I. +1 more
In this second part of our statistical study of the mid-altitude cusp, we compare the cusp morphology, as seen in the Cluster ion spectrometer (CIS), to the interplanetary magnetic field (IMF) orientation. We first recall the method we have used a) to define the cusp properties, b) to sort IMF conditions or behaviour in classes, c) to determine th…
The unusual 2006 dwarf nova outburst of GK Persei
Osborne, J. P.; Beardmore, A. P.; Evans, P. A. +1 more
The 2006 outburst of GK Persei differed significantly at optical and ultraviolet (UV) wavelengths from typical outbursts of this object. We present multiwavelength (X-ray, UV and optical) Swift and AAVSO data, giving unprecedented broad-band coverage of the outburst, allowing us to follow the evolution of the longer-than-normal 2006 outburst acros…