Search Publications
Infrared Space Observatory Measurements of [C II] Line Variations in Galaxies
Helou, G.; Stacey, G.; Malhotra, S. +11 more
We report measurements of the [C II] fine-structure line at 157.714 µm in 30 normal star-forming galaxies with the Long Wavelength Spectrometer (LWS) on the Infrared Space Observatory (ISO). The ratio of the line to total far-infrared (FIR) luminosity, L[CII]/LFIR, measures the ratio of the cooling of gas to that of dus…
Infrared Spectroscopy of Dust in the Diffuse Interstellar Medium toward Cygnus OB2 No. 12
de Graauw, Th.; Prusti, T.; van Dishoeck, E. F. +7 more
Observations made with the short-wavelength spectrometer of the Infrared Space Observatory are used to investigate the composition of interstellar dust in the line of sight to Cygnus OB2 No. 12, commonly taken as representative of the diffuse (low-density) interstellar medium. Results are compared with data for the Galactic center source Sgr A*. N…
Discovery of Interstellar Hydrogen Fluoride 1
Neufeld, David A.; Phillips, Thomas G.; Schilke, Peter +1 more
We report the first detection of interstellar hydrogen fluoride. Using the Long Wavelength Spectrometer of the Infrared Space Observatory (ISO), we have detected the 121.6973 µm J=2-1 line of HF in absorption toward the far-infrared continuum source Sagittarius B2. The detection is statistically significant at the 13 σ level. On the basis of…
Models for Dense Molecular Cloud Cores
Neufeld, David A.; Doty, Steven D.
We present a detailed theoretical model for the thermal balance, chemistry, and radiative transfer within quiescent dense molecular cloud cores that contain a central protostar. In the interior of such cores, we expect the dust and gas temperatures to be well coupled, while in the outer regions CO rotational emissions dominate the gas cooling and …
Discovery of Far-Infrared Pure Rotational Transitions of CH+ in NGC 7027
Barlow, M. J.; Cernicharo, J.; González-Alfonso, E. +4 more
We report the discovery of the rotational spectrum of CH+ in the Infrared Space Observatory Long Wavelength Spectrometer (LWS) spectrum of the planetary nebula NGC 7027. The identification relies on a 1996 reanalysis of the LWS spectrum by Liu et al. and on new LWS data. The strong line at 179.62 µm (coinciding with the 212
New Wavelength Determinations of Mid-Infrared Fine-structure Lines by Infrared Space Observatory Short Wavelength Spectrometer
Lutz, D.; Heras, A. M.; Beintema, D. A. +18 more
We report accurate new wavelengths for 29 mid-infrared ionic fine-structure lines, based on observations with the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory (ISO). Our results originate from observations of NGC 7027, NGC 6543, NGC 6302, the Circinus galaxy, Sgr A West, and W51 IRS 2. The obtained accuracies (λ/Δλ) …
Potential Measurement of the Luminosity Function of 158 Micron [C II] at High Redshifts: A Test of Galaxy Formation Models
Stark, Antony A.
Galaxy formation scenarios predict a burst of star formation in normal galaxies at a redshift between z ~ 2 and z ~ 6 (e.g., Katz & Gunn 1991); such a starburst may be accompanied by a significant brightening of the λ = 158 µm line of C+. Galaxies that will evolve to a total luminosity L* = 5 × 1010 L
Macromolecules, Very Small Grains, and Large Dust Particles in the Whirlpool Galaxy M51 and Its Companions: A Unified View
Sauvage, Marc; Elmegreen, Bruce G.; Stockton, Alan +1 more
A combined image using optical and mid-infrared ISOCAM data of the galaxy M51 and its companion reveals a unified view of the distribution of dust grains of all sizes. The image shows the large grains in extinction at blue light and the small grains in emission at 15 µm. Much of the emission from small grains coincides with extinction from l…
Charge Transfer between Neutral Atoms and Highly Ionized Species: Implications for ISO Observations
Korista, K. T.; Ferland, G. J.; Dalgarno, A. +1 more
We estimate rate coefficients for charge transfer between neutral hydrogen and helium and moderately to highly ionized heavy elements. Although charge transfer does not have much influence on hot collisionally ionized plasmas, its effects on photoionized plasmas can be profound. We present several photoionization models that illustrate the signifi…
The Nature of the Far-Infrared Emission from Seyfert Galaxies
Pérez García, A. M.; Rodríguez Espinosa, J. M.
Optical R-band imaging data and far-infrared (FIR) Infrared Space Observatory data from Seyfert galaxies are combined to show that the compact optical emission from the nuclear and circumnuclear region correlates reasonably well with the warm FIR emission that is observed in these objects, while the extended optical emission, which essentially ori…