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The star, B Pictoris, is a normal main sequence star with a remnant disc of cool dust around it. We present observations of the B pic dust disc in the far infrared, obtained using the photometer (ISOPHOT) on the Infrared Space Observatory (ISO) satellite.
A short outline is given of the Infrared Space Observatory Camera (ISOCAM), one of the 4 instruments onboard the Infrared Space Observatory (ISO), with the current status of its two 32x32 arrays, an InSb charge injection device (CID) and a Si:Ga direct read-out (DRO), and the results of the in orbit radiation simulation with gamma ray sources. A tentative technique for the evaluation of the flat fielding accuracy is also proposed.
Although half the luminosity of the universe appears in the band from 20-450 $\mu$m, almost nothing is known about the sources of this radiation. Moreover, many molecules, atoms, and ions of astrophysical interest have some of their strongest lines in this wavelength range. Now Infrared Astronomy Satellite (IRAS) and ISO have flown, Space Infrared Telescope Facility (SIRTF) is nearly ready, SOFIA is under construction, and NGST, ALMA, Herschel, Planck, and a dozen 8 m and a 25 m ground-based visible/near IR telescopes could all be operational by the end of decade. Nevertheless, the mid and far IR region will still not have telescopes that are comparable to neighboring bands in energy sensitivity or angular resolution, despite these many advances. What scientific questions will still be open, and what instrumentation will be required? We anticipate that cold filled-aperture telescopes operating out to 100 $\mu$m and cold imaging interferometers, operating out to about 450 $\mu$m in space could be very powerful, using direct detection rather than heterodyne systems. I will give a brief overview of the scientific questions that may still be open, the main factors governing the choice of equipment, and the technological developments that would be required to actually build and use these new facilities.
The low resolution far infrared spectrum of the galaxy Arp 220, obtained with the low wavelength spectrometer (LWS) onboard the Infrared Space Observatory (ISO), is presented. The spectrum is dominated by the OH, H2O, CH, NH3 and O I absorption lines. The upper limits on the far infrared fine structure lines indicate a softer radiation in Arp 220 than in starburst galaxies.
Energetic emitting regions have traditionally been studied via x-ray, UV and optical emission lines of highly ionized intermediate mass elements. Such lines are often referred to as 'coronal lines' since the ions, when produced by collisional ionization, reach maximum abundance at electron temperatures of approx. 10(exp 5) - 10(exp 6) K typical of the sun's upper atmosphere. However, optical and UV coronal lines are also observed in a wide variety of Galactic and extragalactic sources including the Galactic interstellar medium, nova shells, supernova remnants, galaxies and QSOs. Infrared coronal lines are providing a new window for observation of energetic emitting regions in heavily dust obscured sources such as infrared bright merging galaxies and Seyfert nuclei and new opportunities for model constraints on physical conditions in these sources. Unlike their UV and optical counterparts, infrared coronal lines can be primary coolants of collisionally ionized plasmas with 10(exp 4) less than T(sub e)(K) less than 10(exp 6) which produce little or no optical or shorter wavelength coronal line emission. In addition, they provide a means to probe heavily dust obscured emitting regions which are often inaccessible to optical or UV line studies. In this poster, we provide results from new model calculations to support upcoming Infrared Space Observatory (ISO) and current ground-based observing programs involving infrared coronal emission lines in AGN. We present a complete list of infrared (lambda greater than 1 micron) lines due to transitions within the ground configurations 2s(2)2p(k) and 3s(2)3p(k) (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (x greater than or equal to 100 eV) astrophysically abundant (n(X)/n(H) greater than or equal to 10(exp -6)) elements. Included are approximately 74 lines in ions of O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni spanning a wavelength range of approximately 1 - 280 microns. We present new results from detailed balance calculations, new critical densities for collisional de-excitation, intrinsic photon rates, branching ratios, and excitation temperatures for the majority of the compiled transitions. The temperature and density parameter space for dominant cooling via infrared coronal lines is presented, and the relationship of infrared to optical coronal lines is discussed.
One of the four focal plane instruments of the Infrared Space Observatory (ISO) is ISOPHOT, a photopolarimeter for the wavelength region 3 to 200 microns. Each experiment occupies a quadrant of the focal plane. The telescope beam is directed into each experiment by means of a pyramid mirror and by tilting the satellite. The diameter of the unvignetted field of view is 3 arcmin or 7.85 mm in the focal plane (1 mm = 23 arcsec). The temperatures provided are 3 K for cooling the detector systems and 8 K for the experiment structure. Available detectors are described along with the current status of the experiment.
The observations of Titan performed by the Infrared Space Observatory (ISO) short wavelength spectrometer (SWS), in the 2 micrometer to 45 micrometer region using the grating mode, are reported on. Special attention is given to data from Titan concerning 7 micrometer to 45 micrometer spectral resolution. Future work for improving Titan's spectra investigation is suggested.
A block grant supported several astronomers who executed observing programs using the Infrared Space Observatory (ISO). The ISO project in which Harriet Dinerstein participated was a study of sulfur and neon abundances in extragalactic H II regions using the ISO Short Wavelength Spectrometer (SWS). Evans and Jaffe, along with collaborators Ewine van Dishoeck and Wing-Fai Thi, and then graduate student Wenbin Li, carried out an in-depth study of the peripheral region of the molecular cloud L1204/S140, where the far ultraviolet radiation and the density are relatively low. Their observations test theories of photon-dominated regions (PDRs) in a regime that has been little explored. One ISO program was involved with PHT-32 observations of about a dozen young stars to search for extended emission that could be modeled with our dust-modeling-code at UT. The document reports on preliminary analysis of PHT 32 scanning of 10 pre-main-sequence stars at 50 and 100 microns. A small sample of R Coronae Borealis stars was observed with the SWS.
The Short Wave Spectrometer (SWS) is one of the two spectrometers for the Infrared Space Observatory (ISO). It consists of a pair of grating spectrometers and a Fabry-Perot interferometer. Together, the grating spectrometers cover the wavelength range 2.4 to 45 microns, at a resolution between 1000 and 2000. The Fabry-Perot interferometer, in series with one of the grating spectrometers, provides a resolution of about 20,000 at the wavelengths between 15 and 35 microns. The SWS is being built by the Space Research Organization of the Netherlands and the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. The spectrometer has 52 discrete detectors, most of which are bulk detectors. In the design of the spectrometer, the main emphasis is on the sensitivity of the individual channels, rather than on the number of detectors. This was one of the main reasons to select non-destructive read-out circuits, with a separate heated-JFET pre-amplifier for each individual detector. The signals are amplified and filtered in parallel. The engineering tests on the SWS detector block have not yet been completed. The design of the detector block is described and the present problem areas are indicated.
This volume consists of 37 papers which summarize results presented at the Third Infrared Detector Technology Workshop, held February 7-9, 1989, at Ames Research Center. The workshop focused on infrared (IR) detector, detector array, and cryogenic electronic technologies relevant to low-background space astronomy. Papers on discrete IR detectors, cryogenic readouts, extrinsic and intrinsic IR arrays, and recent results from ground-based observations with integrated arrays were given. Recent developments in the second-generation Hubble Space Telescope (HST) infrared spectrometer and in detectors and arrays for the European Space Agency's Infrared Space Observatory (ISO) are also included, as are status reports on the Space Infrared Telescope Facility (SIRTF) and the Stratospheric Observatory for Infrared Astronomy (SOFIA) projects.
This paper will review our current knowledge of circumstellar and interstellar dust with the emphasis on infrared spectroscopy with ISO. Objects embedded in or located behind molecular clouds show a wealth of absorption features due to simple molecules in an icy mantle. The SWS on ISO has provided us, for the first time, with complete 3-45 um spectra which allow an inventory of interstellar ice. Among the species identified are H2O, CH3OH, CH4, CO2, CO, and OCS. These species are formed through simple reactions among gas phase species accreted on grain surfaces, possibly modified by FUV photolysis and warm-up (ie., outgassing). The implications of the observations for our understanding of these processes will be reviewed. The IR spectra of many UV bright objects are dominated by strong emission features at 3.3, 6.2, 7.7, and 11.3 micrometers. These are generally attributed to Polycyclic Aromatic Hydrocarbons (PAHs) molecules. The observational evidence will be reviewed. The emphasis will be on recent data which show widespread spectral variations, particularly among protoplanetary and planetary nebulae, and their implications. One of the most exciting, recent discoveries on interstellar and circumstellar dust has been the detection of spectral structure due to crystalline olivine and enstatite in a variety of objects surrounded by circumstellar silicates. These spectra will be reviewed and circumstellar silicate mineralogy will be discussed.
The software which is currently being developed for the Short Wavelength Spectrometer (SWS) of the Infrared Space Observatory (ISO) is described. The spectrometer has a wide range of capabilities in the 2-45 micron infrared band. SWS contains two independent gratings, one for the long and one for the short wavelength section of the band. With the gratings a spectral resolution of approximately 1000 to approximately 2500 can be obtained. The instrument also contains two Fabry-Perault's yielding a resolution between approximately 1000 and approximately 20000. Software is currently being developed for the acquisition, calibration, and analysis of SWS data. The software is firstly required to run in a pipeline mode without human interaction, to process data as they are received from the telescope. However, both for testing and calibration of the instrument as well as for evaluation of the planned operating procedures the software should also be suitable for interactive use. Thirdly the same software will be used for long term characterization of the instrument. The software must work properly within the environment designed by the European Space Agency (ESA) for the spacecraft operations. As a result strict constraints are put on I/O devices, throughput etc.
We present the results of imaging spectroscopy of the reflection nebula vdB 133, obtained with the infrared camera and circular varable filter wheel on the Infrared Space Observatory (ISO).
We discuss the photometric calibration of ISOPHOT for point sources in the wavelength range from 3.2 to 240 ??or the aperture photometer and the FIR camera section.
The origin of the infrared emission in Active Galactic Nuclei (AGN), whose strength is comparable to the optical/ultraviolet (OUV) emission, is generally thought to be a combination of thermal emission from dust and non-thermal, synchrotron emission. Although data are sparse, particularly in the far-infrared, the broad wavelength range of this emission suggests a wide range of temperatures and a combination of AGN and starburst heating mechanisms. The strength of the non-thermal emission is expected to be related to the radio emission. While this scenario is well-established, basic questions, such as the spatial and temperature distribution of the dust, the relative importance of AGN and starburst heating, and the significance of the non-thermal contribution remain largely undetermined. The wide wavelength range of the Infrared Space Observatory (ISO) combined with its arcmin spatial resolution and increased sensitivity facilitated the observation of a larger subset of the AGN population than previously covered, allowing these questions to be investigated in more detail. This paper will review the spectral energy distributions (SED) of AGN with particular emphasis on the infrared emission and on ISO's contributions to our knowledge. Preliminary results from ISO observations of X-ray selected and high-redshift AGN will be described.
We have observed 19 Virgo cluster spiral galaxies with the Long Wavelength Spectrometer (LWS) onboard ESAs Infrared Space Observatory (ISO) obtaining spectra around the [CII] 157.741 ??ine structure line.
ESA's Infrared Space Observatory (ISO), scheduled for launch within the next 2-3 years, will place a complement of powerful infrared imagers and spectrometers into high orbit, with an operational life anticipated to be about 18 months. During this time, numerous scientific investigations of every conceivable astrophysical target will be made. The purpose of this paper is to consider the instrumental complement in terms of specific observations of Vega-like systems with cold, infrared excesses, in order to investigate problems relating to the evolution of planetary systems, and to optimize the scientific results possible with ISO on such topics.
The photometer (ISOPHOT) on the Infrared Space Observatory (ISO) has proved to be invaluable for investigating the dust around main sequence stars (both prototypes and candidate Vega-like Stars).