Search Publications
ISM parameters in the normal galaxy NGC 5713.
Helou, G.; Lord, S. D.; Malhotra, S. +11 more
We report ISO Long Wavelength Spectrometer (LWS) observations of the Sbc galaxy NGC 5713. We have obtained strong detections of the fine-structure forbidden transitions [CII] 158µm, [OI] 63µm, and [OIII] 88µm, and significant upper limits for [NII] 122µm, [OIII] 52µm, and [NIII] 57µm, and have measured the galax…
Observations of galactic cosmic rays and the anomalous helium during ULYSSES passage from the south to the north solar pole.
Simpson, J. A.; McKibben, R. B.; Zhang, M. +2 more
We compare observations of the modulated intensities and spectra of galactic cosmic ray nuclei and anomalous helium above 30 MeV/n measured by the COsmic and Solar Particle INvestigations (COSPIN) High Energy Telescope (HET) on Ulysses with similar observations from the IMP-8 earth-orbiting satellite between September 1994 and August 1995. During …
The SWS survey for rotational H_2_ lines in late-type galaxies. Observations of the central regions of NGC 6946.
de Graauw, T.; van der Werf, P. P.; de Jong, T. +1 more
We report the first extragalactic detection of the pure rotational H_2_ S(0) and S(1) lines at 28.2 and 17.0µm in the central 130pc molecular complex of the nearby Scd galaxy NGC 6946. We deduce a temperature of this gas component of 170K and a mass of 5x10^6^Msun_ for an ortho/para ratio of 3, corresponding to the ratio of statis…
Extragalactic symbiotic systems. III. The stellar components of the systems in the Magellanic Clouds.
Vogel, M.; Schild, H.; Muerset, U.
We present multifrequency data, ranging from ultraviolet and optical spectroscopy to infrared photometry, of the confirmed symbiotic systems in both Magellanic Clouds (SMC1, SMC2, SMC3, N60, Ln358, N73, S154, S147, LMC1, N67, and S63), as well as of Sanduleak's star, whose nature remains unclear. Because of the known distance, the Magellanic symbi…
Bimodal dust emission in three classical Seyfert galaxies: NGC 3227, NGC 4051 and NGC 4151.
Meisenheimer, K.; Lemke, D.; Rodriguez Espinosa, J. M. +1 more
Far Infrared observations of the Seyfert galaxies NGC 3227, NGC 4051 and NGC 4151 are presented. These are the first data from a complete sample of Seyfert galaxies that is being observed by ISO as part of the ISOPHOT guaranteed time. The new ISO data, in combination with the IRAS data, show that the mid to far IR emission in all three objects can…
Iron and nickel abundances of subluminous O-stars. I. NLTE-model atmospheres with line blanketing by iron group elements.
Werner, K.; Dreizler, S.; Heber, U. +2 more
NLTE model atmospheres for hot evolved stars including line blanketing of all iron group elements were first constructed by Dreizler & Werner (1993). In this paper we improve computational details and check the adopted simplifications. We also present a systematic investigation of the consequences of iron group line blanketing on the atmospher…
The mid-infrared color of NGC 6946.
Helou, G.; Lord, S. D.; Malhotra, S. +10 more
We analyze the new mid-infrared maps of NGC 6946 for variations in the color ratio of the 7-to-15µm emission. Our preliminary findings are that this mid-infrared color is remarkably constant between arms and inter-arm regions, and as a function of radius in the disk, excluding the nuclear region. As surface brightness ranges by more than an …
Theoretical amplitudes of solar g-modes.
Andersen, B. N.
This work presents predictions on the amplitudes of solar g-modes. It is based on the assumption that convective overshoot into the convectively stable interior generates gravity waves. Based on this assumption it is possible to estimate values for the amplitude of the g-modes below the solar convection zone. Numerical simulations, giving the tran…
The regular structure of shock-accelerated ~40-100keV electrons in the high latitude heliosphere.
Simnett, G. M.; Tappin, S. J.; Roelof, E. C.
The passage of Ulysses through the high latitude heliosphere has given us a new insight into the interplanetary dynamical processes which are occurring, at any rate near solar minimum, in the heliosphere above the streamer belt. We report here observations of ~40-100keV electrons and ~0.5MeV protons detected by HI-SCALE from 1992-96. Apart from a …
ULYSSES observations of pressure-balance structures in the polar solar wind.
Forsyth, R.; Balogh, A.; McComas, D. J. +4 more
Throughout its high-latitude excursion Ulysses has observed several types of solar wind structures. In addition to structures such as Alfven waves, compressional features, and microstreams, the solar wind also contains low contrast pressure-balance structures (PBSs). The PBSs are marked by an anti-correlation of the plasma and field pressures; the…