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A 0.4-20 mu m spectroscopic study of the clumped wind of WR 147
Hillier, D. J.; Crowther, P. A.; Willis, A. J. +4 more
We present a detailed spectroscopic study of the WN8(h)+B0.5 V binary system WR 147 using a non-LTE model that incorporates advances in line blanketing and allows for clumping in the wind. Ground-based optical and near-infrared observations, and high-resolution spectra obtained with the ISO Short Wavelength Spectrometer are combined for this study…
Fundamental parameters of Galactic luminous OB stars. IV. The upper HR diagram
Herrero, A.; Puls, J.; Villamariz, M. R.
We present observations and analyses of seven Galactic O stars of type O6 and earlier. The analyses are carried out using NLTE plane-parallel, hydrostatic models as well as NLTE spherical models with mass-loss. With detailed calculations for the former and simulations for the latter, it is shown that the flux blocking due to UV metal lines is impo…
Dust in PG quasars as seen by ISO
Meisenheimer, K.; Lemke, D.; Klaas, U. +5 more
Infrared to millimeter spectral energy distributions (SEDs) have been obtained for a random sample of 17 Palomar Green quasars. The observations were carried out between 4.8 and 200 mu m with ISO and supplemented for ten sources with IRAM at 1.3 mm. Eight sources were detected in the far infrared for the first time. The SEDs provide evidence for c…
The HST view of the FR I / FR II dichotomy
Capetti, A.; Chiaberge, M.; Celotti, A.
In order to explore how the FR I / FR II dichotomy is related to the nuclear properties of radio galaxies, we studied a complete sample of 26 nearby FR II radio galaxies using Hubble Space Telescope (HST) images and compared them with a sample of FR I previously analyzed. FR I nuclei lie in the radio-optical luminosity plane along a tight linear c…
The ISOPHOT 170 µ m serendipity survey. I. Compact sources with galaxy associations
Kessler, M. F.; Lemke, D.; Rowan-Robinson, M. +6 more
The first set of compact sources observed in the ISOPHOT 170 µm Serendipity Survey is presented. From the slew data with low (I100 µm <= 15 MJy/sr) cirrus background, 115 well-observed sources with a high signal-to-noise ratio in all detector pixels having a galaxy association were extracted. Of the galaxies with known op…
Mid-infrared imaging and spectrophotometry of N 66 in the SMC with ISOCAM
Boulanger, F.; Sauvage, M.; Contursi, A. +8 more
We present observations with the mid-infrared camera ISOCAM on board the Infrared Space Observatory of the major star-forming region N 66 in the Small Magellanic Cloud (SMC) and of its surroundings. These observations were performed with broad filters and Circular Variable Filters giving a spectral resolution of about 40. In addition, CO(2-1) data…
ISO deep far-infrared survey in the ``Lockman Hole". II. Power spectrum analysis: evidence of a strong evolution in number counts
Sanders, D. B.; Kawara, K.; Taniguchi, Y. +8 more
We investigate the characteristics of FIR brightness fluctuations at 90 mu m and 170 mu m in the Lockman Hole, which were surveyed with ISOPHOT aboard the Infrared Space Observatory (ISO). We first calculated the angular correlation function of each field and then its Fourier transform (the angular Power Spectral Density: PSD) over the spatial fre…
The cometary blue compact dwarf galaxies Mkn 59 and Mkn 71. A clue to dwarf galaxy evolution?
Thuan, T. X.; Izotov, Y. I.; Papaderos, P. +3 more
``Cometary'' Blue Compact Dwarf Galaxies (iI,C BCDs) are characterized by an off-center starburst close to the end of their elongated stellar bodies. This rare phenomenon may carry some clues on how collective star formation ignites and propagates in gas-rich low-mass stellar systems. This off-center burst may be a fortuitous enhancement of the ot…
The evolution of the color gradients of early-type cluster galaxies
Greggio, L.; Saglia, R. P.; Bender, R. +2 more
We investigate the origin of color gradients in cluster early-type galaxies to probe whether pure age or pure metallicity gradients can explain the observed data in local and distant (z ≈ 0.4) samples. We measure the surface brightness profiles of the 20 brightest early-type galaxies of CL0949+44 (hereafter CL0949) at redshift z=0.35-0.38 from HST…
The elusive active nucleus of NGC 4945
Maiolino, R.; Marconi, A.; Macchetto, F. +4 more
We present new HST NICMOS observations of NGC 4945, a starburst galaxy hosting a highly obscured active nucleus that is one of the brightest extragalactic sources at 100 keV. The HST data are complemented with ground based Fe II line and mid-IR observations. A 100pc-scale starburst ring is detected in Paα, while H2 traces the walls of a…