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An XMM-Newton observation of the dynamically active binary cluster A1750
Pratt, G. W.; Bourdin, H.; Sauvageot, J. -L. +1 more
We present results from the XMM-Newton observation of the binary cluster A1750 at z = 0.086. We have performed a detailed study of the surface brightness, temperature and entropy distribution and confirm that the two main clusters of the system (A1750 N and A1750 C) have just started to interact. From the temperature distribution, we calculate tha…
The Araucaria Project: An Improved Distance to the Sculptor Spiral Galaxy NGC 300 from Its Cepheid Variables
Udalski, Andrzej; Soszyński, Igor; Minniti, Dante +8 more
In a previous paper, we reported on the discovery of more than a hundred new Cepheid variables in the Sculptor Group spiral galaxy NGC 300 from wide-field images taken in the B and V photometric bands at ESO/La Silla. In this paper, we present additional VI data, derive improved periods and mean magnitudes for the variables, and construct period-l…
Lightning on Jupiter observed in the Hα line by the Cassini imaging science subsystem
West, Robert A.; Porco, Carolyn C.; Dyudina, Ulyana A. +4 more
Night side images of Jupiter taken by the Cassini Imaging Science Subsystem (ISS) camera with the H filter reveal four lightning clusters; two of them are repeated observations of the same storm. All of these flashes are associated with storm clouds seen a few hours earlier on the day side of Jupiter. Some of the clouds associated with lightning d…
The Nature of the Mid-Infrared Population from Optical Identifications of the ELAIS-S1 Sample
Pozzi, F.; Danese, L.; Alexander, D. M. +16 more
We present a multiwavelength catalog (15 µm, R-band, K-band, and 1.4 GHz flux) plus spectroscopic identifications for 406 15 µm sources detected in the European Large Area ISO Survey (ELAIS) region S1, over the flux density range 0.5<S15µm<150 mJy. Three hundred thirty-two (~82%) sources are optically identified …
Optical observations of Comet 67P/Churyumov-Gerasimenko
Rauer, H.; Weiler, M.; Helbert, J.
From longslit spectra obtained during the 1996 perihelion passage of Comet 67P/Churyumov-Gerasimenko, a CN production rate of (1.35 ± 0.35) × 1025 molecules s-1 was determined and an upper limit for the C3 production rate of 1 × 1025 molecules s-1 was derived. The dust color and dust activity …
Activity-related Changes in Local Solar Acoustic Mode Parameters from Michelson Doppler Imager and Global Oscillations Network Group
Howe, R.; Hill, F.; Hindman, B. W. +2 more
We use the ring-diagram technique of local helioseismology to study the amplitude and line width of high-degree solar acoustic modes from 474 days of data from the Michelson Doppler Imager Dynamics program, covering the period 1996-2002. The 2002 data are compared with contemporaneous data from the Global Oscillations Network Group network. The re…
Is M82 X-1 Really an Intermediate-Mass Black Hole? X-Ray Spectral and Timing Evidence
Titarchuk, Lev; Fiorito, Ralph
Ultraluminous X-ray sources (ULXs) with apparent luminosities up to hundreds of times the Eddington luminosity for a neutron star have been discovered in external galaxies. The existence of intermediate-mass black holes has been proposed to explain these sources. We present evidence for an intermediate-mass black hole in the ULX M82 X-1 based on t…
Intrinsic Absorption in the Spectrum of Markarian 279: Simultaneous Chandra, FUSE, and STIS Observations
Kaiser, Mary Elizabeth; Green, Richard F.; Scott, Jennifer E. +12 more
We present a study of the intrinsic X-ray and far-ultraviolet absorption in the Seyfert 1.5 galaxy Markarian 279 using simultaneous observations from the Chandra X-ray Observatory, the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope, and the Far Ultraviolet Spectroscopic Explorer (FUSE). We also present FUSE observations mad…
X-Ray Pulsars in the Small Magellanic Cloud
Lamb, R. C.; Macomb, D. J.; Majid, W. A.
XMM-Newton archival data for the Small Magellanic Cloud have been examined for the presence of previously undetected X-ray pulsars. One such pulsar, with a period of 202 s, is detected. Its position is consistent with an early B star in the SMC, and we identify it as a high-mass X-ray binary (HMXB). In the course of this study we determined the pu…
Multi-wavelength study of a high-latitude EUV filament
Heinzel, Petr; Schmieder, Brigitte; Schwartz, Pavol +1 more
A large filament was observed during a multi-wavelength coordinated campaign on June 19, 1998 in the Hα line with the Swedish Vacuum Solar Telescope (SVST) at La Palma, in the coronal lines Fe ix/x 171 Å and Fe xi 195 Å with the Transition Region and Coronal Explorer (TRACE) and in EUV lines with the SOHO/CDS spectrometer and the hydrogen Lyman se…