Search Publications
Latitude variations of ~7MeV and >300MeV cosmic ray electron fluxes in the heliosphere: ULYSSES COSPIN/KET results and implications.
Sierks, H.; Kunow, H.; Wibberenz, G. +8 more
The 160° latitude scan performed in less than one year between summer 1994 and summer 1995 by Ulysses allowed us to obtain unique data about the latitudinal dependence of the cosmic ray fluxes. We present in this paper results on the electron component derived from the COSPIN/KET instrument onboard Ulysses, both at MeV and GeV energies. The variat…
R4 in the Small Magellanic Cloud: a spectroscopic binary with a B[e]/LBV-type component.
Stahl, O.; Zickgraf, F. -J.; Wolf, B. +3 more
During the past twelve years we observed several spectra of the B[e] star R4 in the SMC with CASPEC at ESO, La Silla. We also obtained UBV(RI) and JHK photometry during various occasions at La Silla. Further photometry was available in the literature. Brightness variations typical for LBVs of about 0.7mag in V were found. The optical spectra are d…
The Metallicity Dependence of the Stellar Luminosity and Initial Mass Function: HST Observations of Open and Globular Clusters
Tanvir, Nial; Gilmore, Gerard; von Hippel, Ted +2 more
Using HST and the WFPC2 we have acquired very deep V- and I-band photometry of stars in NGC 2420 and NGC 2477 to study cluster luminosity functions at approximately solar metallicity. We have determined these cluster luminosity functions down to M1=10.5(0.2 Msun) and find that the luminosity function of NGC 2420 turns over at…
A Two-Wind Interaction Model for Proplyds
Henney, W. J.; Raga, A. C.; Curiel, S. +1 more
Recent HST observations of the Orion Nebula show the presence of compact (∼2") emission-line objects ("proplyds") with bowlike morphologies and tails pointing away from the θ1C Ori star. We model these objects as the result of the interaction between the fast wind from θ1C and slow dense winds from accretion disks around youn…
First detection of the 56-µm rotational line of HD in Saturn's atmosphere.
Ade, P. A. R.; Lellouch, E.; Encrenaz, T. +25 more
The R(1) rotational line of HD at 56.23µm has been detected for the first time on Saturn using the Long Wavelength Spectrometer (LWS) on board the Infrared Space Observatory (ISO). The measurements were made using the LWS in Fabry-Perot mode in January 1996 during the ISO performance verification phase. The measured spectrum has been compare…
The Dual Nature of Hard X-Ray Outbursts from the Superluminal X-Ray Transient Source GRO J1655-40
Rupen, M. P.; Zhang, S. N.; Livio, M. +5 more
We report the results of multiwavelength observations of the superluminal X-ray transient GRO J1655-40 during and following the prominent hard X-ray outburst of 1995 March--April. GRO J1655-40 was monitored continuously by BATSE on board the Compton Gamma Ray Observatory and observed repeatedly in the radio and optical bands from the ground. About…
``Chain'' Galaxies are Edge-on Low Surface Brightness Galaxies
Dalcanton, Julianne J.; Shectman, Stephen A.
Deep HST WFPC2 images have revealed a population of very narrow blue galaxies, which Cowie et al. have interpreted as being a new morphological class of intrinsically linear star forming galaxies at z = 0.5--3. We show that the same population exists in large numbers at low redshifts (z ~ 0.03) and are actually the edge-on manifestation of low sur…
Ultraviolet Imaging of NGC 3310: A Merger-driven Global Starburst
O'Connell, Robert W.; Bohlin, Ralph C.; Smith, Andrew M. +8 more
We present the first far-ultraviolet (FUV; lambda ~ 1500 A) image of the nearby peculiar SAB(r)bc galaxy NGC 3310. The small 15" (945 pc) diameter circumnuclear starburst ring is the most luminous structure, producing 30% of the total observed FUV luminosity. Diffuse emission from the inner disk (20" < R < 40") contributes another ~20% of th…
LWS observations of the bright rimmed globule IC 1396N.
Ade, P. A. R.; Liseau, R.; White, G. J. +36 more
We present the first far-infrared spectrum of the IRAS source associated with IC 1396N, located in the HII region IC 1396 together with submillimeter and millimeter photometry. A rich spectrum of CO, OH, and H_2_O lines are detected in the ISO-LWS spectrum, indicative of a warm, dense region, probably shock excited, around the source. Among the fi…
Molecular hydrogen observations of Cepheus A West.
de Graauw, T.; van der Werf, P. P.; Wright, C. M. +3 more
The Herbig-Haro complex GGD37 is an active region in the west of Cepheus A. We have used the ISO Short Wavelength Spectrometer (SWS) to investigate the physics of this region by observations of molecular hydrogen and forbidden atomic and ionic emission lines over a wide wavelength and excitation energy range. We find excitation temperatures of the…