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A deep XMM-Newton observation of the ultraluminous X-ray source Holmberg II X-1: the case against a 1000-Msolar black hole
Uttley, P.; Reeves, J. N.; Roberts, T. P. +1 more
We present results from a 112-ks long look by XMM-Newton at the ultraluminous X-ray source (ULX) Holmberg II X-1 (Ho II X-1), long thought to be the one of best candidates for the missing class of intermediate-mass black holes (IMBHs). Our data comprises the first high-quality XMM-Newton/RGS (reflection grating spectrometer) spectrum of an ULX, an…
The Orbits of Saturn's Small Satellites Derived from Combined Historic and Cassini Imaging Observations
Porco, C. C.; Spitale, J. N.; Jacobson, R. A. +1 more
We report on the orbits of the small, inner Saturnian satellites, either recovered or newly discovered in recent Cassini imaging observations. The orbits presented here reflect improvements over our previously published values in that the time base of Cassini observations has been extended, and numerical orbital integrations have been performed in…
The Araucaria Project: The Distance to the Local Group Galaxy IC 1613 from Near-Infrared Photometry of Cepheid Variables
Soszyński, Igor; Dall'Ora, Massimo; Bono, Giuseppe +5 more
We have measured accurate near-infrared magnitudes in the J and K bands of 39 Cepheid variables in the irregular Local Group galaxy IC 1613 with well-determined periods and optical VI light curves. Using the template light curve approach of Soszyński, Gieren, & Pietrzyński, accurate mean magnitudes were obtained from these data, which allowed …
The supermassive black hole in Centaurus A: a benchmark for gas kinematical measurements
Marconi, A.; Capetti, A.; Koekemoer, A. M. +5 more
We present new HST Space Telescope Imaging Spectrograph observations of the nearby radio galaxy NGC 5128 (Centaurus A). The bright emission line with longest wavelength accessible from HST, [S III]λ 9533 Å, was used to study the kinematics of the ionized gas in the nuclear region with a 0.1 arcsec spatial resolution. The STIS data were analized in…
Multifrequency variability of the blazar AO 0235+164 . The WEBT campaign in 2004-2005 and long-term SED analysis
Lee, C. -U.; Ilyin, I.; Lähteenmäki, A. +58 more
Aims.A huge multiwavelength campaign targeting the blazar
Methods: .Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointing…
Cassini observations of planetary-period magnetic field oscillations in Saturn's magnetosphere: Doppler shifts and phase motion
Dougherty, M. K.; Nichols, J. D.; Cowley, S. W. H. +5 more
Cassini magnetic field observations show that few-nT oscillations near the planetary rotation period, first observed in Pioneer-11 and Voyager-1 and -2 fly-by data, are essentially ubiquitous in Saturn's magnetosphere, though their character differs between the quasi-dipolar ring current region and the dawn tail. Examination of data from the ring-…
Annihilation Emission from the Galactic Black Hole
Cheng, K. S.; Chernyshov, D. O.; Dogiel, V. A.
Both diffuse high-energy gamma rays and an extended electron-positron annihilation line emission have been observed in the Galactic Center (GC) region. Although X-ray observations indicate that the Galactic black hole Sgr A* is inactive now, we suggest that Sgr A* can become active when a captured star is tidally disrupted and matter is accreted i…
The Absence of Adiabatic Contraction of the Radial Dark Matter Profile in the Galaxy Cluster A2589
Humphrey, Philip J.; Buote, David A.; Brighenti, Fabrizio +4 more
We present an X-ray analysis of the radial mass profile of the radio-quiet galaxy cluster A2589 between 0.015 and 0.25rvir, using an XMM-Newton observation. Except for a ~16 kpc shift of the X-ray center of the R=45-60 kpc annulus, A2589 possesses a remarkably symmetrical X-ray image and is therefore an exceptional candidate for precisi…
The Effects of Space Weathering at UV Wavelengths: S-Class Asteroids
Vilas, Faith; Hendrix, Amanda R.
We present evidence that space weathering manifests itself at near-UV wavelengths as a bluing of the spectrum, in contrast with the spectral reddening that has been seen at visible-near-IR wavelengths. Furthermore, the effects of space weathering at UV wavelengths tend to appear with less weathering than do the longer wavelength effects, suggestin…
GRB 060121: Implications of a Short-/Intermediate-Duration γ-Ray Burst at High Redshift
Sakamoto, T.; McBreen, S.; Pandey, S. B. +23 more
Since the discovery of the first short-population γ-ray burst (GRB) afterglows in 2005, the handful of observed events have been found to be embedded in nearby (z < 1), bright underlying galaxies. We present multiwavelength observations of GRB 060121, the first short burst observed to clearly outshine its host galaxy (by a factor >102