Search Publications
The first detection of Far-Infrared emission associated with an extended HI disk. The case of NGC 891
Tuffs, R. J.; Popescu, C. C.
Spiral galaxies in the local universe are commonly observed to be embedded in extended disks of neutral hydrogen - the so called ``extended HI disks''. Based on observations made using the ISOPHOT instrument on board the Infrared Space Observatory, we report the first detection of cold dust in the extended HI disk of a spiral galaxy. The detection…
Reconstructing a Cepheid Light Curve with Fourier Techniques. I. The Fourier Expansion and Interrelations
Tanvir, Nial R.; Ngeow, Chow-Choong; Kanbur, Shashi M. +2 more
Fourier decomposition is a well-established technique used in the study of stellar pulsation. However, the quality of reconstructed light curves using this method is reduced when the observed data have uneven phase coverage. We use simulated annealing techniques together with Fourier decomposition to improve the quality of the Fourier decompositio…
Unidentified infrared bands in the interstellar medium across the Galaxy
Lemke, D.; Lehtinen, K.; Mattila, K. +2 more
We present a set of 6-12 mu m ISOPHOT-S spectra of the general interstellar medium of the Milky Way. This part of the spectrum is dominated by a series of strong, wide emission features commonly called the Unidentified Infrared Bands. The sampled area covers the inner Milky Way from l = -60 degr to +60 degr with a ten-degree step in longitude and …
XMM-Newton Observation of the 5.25 Millisecond Transient Pulsar XTE J1807-294 in Outburst
Campana, S.; Belloni, T.; Israel, G. L. +2 more
We report on the results obtained for the millisecond transient X-ray pulsar XTE J1807-294 in a 40 minute orbital period system, based on an XMM-Newton target-of-opportunity observation carried out during 2003 March. The source was found at a luminosity level of about 2×1036 ergs s-1 in the 0.5-10 keV range (assuming a distan…
The Optical Counterpart of the Isolated Neutron Star RX J1605.3+3249
Kulkarni, S. R.; van Kerkwijk, M. H.; Kaplan, D. L.
We have detected the optical counterpart to the nearby isolated neutron star RX J1605.3+3249 using observations from the Space Telescope Imaging Spectrometer aboard the Hubble Space Telescope. The counterpart, with m50CCD=26.84+/-0.07 mag and very blue colors, lies close to the ROSAT HRI error circle and within the Chandra error circle.…
Prominence Motions Observed at High Cadences in Temperatures from 10 000 to 250 000 K
De Pontieu, B.; Kucera, T. A.; Tovar, M.
We report here for the first time observations of prominence velocities over a wide range of temperatures and with a high time cadence. Our study of ultraviolet movies of prominences reveals that multi-thermal features with speeds of 5-70 km s−1 perpendicular to the line of sight are common in the prominences which showed traceable moti…
Analysis of Stellar Occultation Data. II. Inversion, with Application to Pluto and Triton
Elliot, J. L.; Person, M. J.; Qu, S.
We present a method for obtaining atmospheric temperature, pressure, and number density profiles for small bodies through inversion of light curves recorded during stellar occultations. This method avoids the assumption that the atmospheric scale height is small compared with the radius of the body, and it includes the variation of gravitational a…
The Spatial Distribution of Fluorescent H2 Emission near T Tauri
Raymond, John; Hartmann, Lee; Calvet, Nuria +1 more
New subarcsecond far-UV observations of T Tau with Hubble Space Telescope STIS show spatially resolved structures in the 2''×2'' area around the star. The structures are apparent in multiline emission of fluorescent H2 pumped by Lyα. One emission structure follows the cavity walls observed around T Tau N in scatter…
Chandra discovery of an X-ray jet and lobes in 3C 15
Leahy, J. P.; Kataoka, J.; Kawai, N. +5 more
We report the Chandra detection of an X-ray jet in 3C 15. The peak of the X-ray emission in the jet is 4.1'' (a projected distance of 5.1 kpc) from the nucleus, and coincident with a component previously identified in the radio and optical jets. We construct the spectral energy distribution (SED) for this component, optical knot C, and find that X…
SPI instrumental background characteristics
Boggs, S.; Knödlseder, J.; von Kienlin, A. +22 more
In its space environment the INTEGRAL observatory is subject to an intense irradiation by energetic cosmic-ray particles that leads, via nuclear interactions with the telescope and spacecraft materials, to an important background of false events. In this paper we present the characteristics of the instrumental background that is observed in the sp…