Feasibility study for an earth simulating infrared source
Infrared source for simulating earthshine radiation in thermal-vacuum chamber
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Infrared source for simulating earthshine radiation in thermal-vacuum chamber
Infrared, optical, and radio observation are described of a newly discovered galactic infrared source. Most of the radiation comes from a 1.''5 diameter infrared source at a temperature of about 150 K, but some visible emission in the form of a symmetrical highly polarized reflection nebulosity is also seen. The object could represent either a very early or a very late stage in stellar evolution.
The development of mid-infrared, high-energy pulses of extremely short pulse duration is of great importance to the strong-field physics community, as it enables extension of the high-harmonic cutoff towards the keV range of photon energies. Here we demonstrate a C r 2 + : Z n S e laser amplifier delivering 7 mJ, 100 fs pulses at 1 kHz repetition rate and 2.4 µm central wavelength with excellent energy stability and beam quality. These pulses are post-compressed to 39 fs, 6.2 mJ, and 115 GW peak power in a novel nonlinear compression scheme. The laser system was used to generate coherent soft x-ray radiation up to 0.6 keV covering the entire water window, which is of high importance for bio-relevant applications. The obtained results open a wide range of applications in nonlinear optics, attosecond and strong-field physics, and remote sensing.
The Infrared Astronomical Satellite (IRAS) survey uncovered a class of Extremely Luminous Far Infrared Sources (ELFS), exhibiting luminosities up to and occasionally exceeding 10 to the 12th power L sub 0. Arguments are presented to show that sources with luminosities L equal to or greater than 3 x 10 to the 10th power L sub 0 may represent gas rich galaxies in collision. The more conventional explanation of these sources as sites of extremely active star formation fails to explain the observed low optical luminosities of ELFS as well as their high infrared excess. In contrast, a collisional model heats gas to a temperature of approx. 10 to the 6th power K where cooling takes place in the extreme ultraviolet. The UV is absorbed by dust and converted into far infrared radiation (FIR) without generation of appreciable optical luminosity. Gas recombination as it cools generates a Lyman alpha photon only once for every two extreme ultraviolet approx. 50eV photons emitted by the 10 to the 6th power gas. That accounts for the high infrared excess. Finally, the model also is able to explain the observed luminosity distribution of ELFS as well as many other traits.
Infrared and radio continuum observations of the multiple infrared source GL 437 show that it consists of a compact H II region plus two objects which are probably early B stars undergoing rapid mass loss. The group of sources appears to be a multiple system of young stars that have recently emerged from the near side of a molecular cloud. Emission in the unidentified 3.3 micron feature is associated with, but more extended than, the emission from the compact H II region; it probably arises from hot dust grains at the interface between the H II region and the molecular cloud.
Microscopic devices consume less power, run hotter, and are more reliable. Simple, compact, lightweight, rapidly-responding reference sources of broadband infrared radiation made available by integrated-circuit technology. Intended primarily for use in calibration of remote-sensing infrared instruments, devices eventually replace conventional infrared sources. New devices also replace present generation of miniature infrared sources. Self-passivating nature of poly-crystalline silicon adds to reliability of devices. Maximum operating temperature is 1,000 K, and power dissipation is only one-fourth that of prior devices.
The Infrared Astronomical Satellite (IRAS) has yielded a large and uniform sample of high quality data for various infrared sources. To interpret the IRAS observations, complementary theoretical studies have been undertaken which often involve modeling in detail the scattering, absorption, and emission of photons by dust grains. In the past decade, significant progress has been made at Rensselaer in the development of radiation transport models for infrared sources. Models with increasing degree of physical realism have been constructed. We review recent progress made in the modeling of infrared sources. Directions for future research in this area are briefly discussed.
Infrared observations from planned space facilities (e.g., ISO (Infrared Space Observatory), SIRTF (Space Infrared Telescope Facility)) will yield a large and uniform sample of high-quality data from both photometric and spectroscopic measurements. To maximize the scientific returns of these space missions, complementary theoretical studies must be undertaken to interpret these observations. A crucial step in such studies is the construction of phenomenological models in which we parameterize the observed radiation characteristics in terms of the physical source properties. In the last decade, models with increasing degree of physical realism (in terms of grain properties, physical processes, and source geometry) have been constructed for infrared sources. Here we review current capabilities available in the phenomenological modeling of infrared sources and discuss briefly directions for future research in this area.
The Catalog of Infrared Observations and its Far Infrared Supplement summarize all infrared astronomical observations at infrared wavelengths published in the scientific literature between 1965 and 1982. The Catalog includes as appendices the Bibliography of infrared astronomy which keys observations in the Catalog with the original journal references, and the index of infrared source positions which gives source positions for alphabetically listed sources in the Catalog. The Catalog data base contains over 85,000 observations of about 10,000 infrared sources, of which about 2,000 have no known visible counterpart.
The Infrared Source Cross-Index is a listing of correlated infrared source names (and positions) for astronomical objects observed at 1-1000 microns. The source names have been obtained from the database of the first edition of the Catalog of Infrared Observations (CIO: NASA RP 1118), covering observations published through l982. Additional identifications were located by correlating these names with identifications contained in other machine-readable astronomical catalogs in the NASA National Space Science Data Center (NSSDC). There are some 80,000 different source names in the Cross-Index, corresponding to over 27,000 unique infrared sources.
The spectral energy distribution and size of the source of infrared radiation from Herschel 36 in M8 have been investigated. Radiation from the diffuse source in the vicinity of the hourglass has been measured. It is shown that a significant fraction of the 10-microns flux comes from an unresolved source centered on Herschel 36. Other stars in M8 have also been investigated as potential sources of infrared radiation.
BM Sco and six other infrared sources near the cluster M6 were observed at infrared wavelengths. BM Sco has the flat free-free spectrum between 1.5 and 8 microns with a small silicate emission feature typical of the NML Tauri-type objects. IRC-30308 is also an infrared star of the NML Tauri type, and IRC-30312 has long wavelength radiation characteristic of the luminous M supergiants. The remaining four sources resemble reddened long-period variables. The presence of these infrared sources near M6 is not statistically significant and is not sufficient to associate them with the cluster.
Far-infrared and submillimeter observations of Orion Molecular Cloud-2 (OMC-2), OMC-1, OMC-3, NGC 2024 and Monoceros R2 are reported. The areas surveyed include far-infrared sources with luminosities between 100 and 250,000 solar luminosities. The data are employed to estimate masses and column densities for the radiating clouds, the radial dependence of the density in the clouds, and the masses of the stellar clusters. Brightness temperatures of both the extended and compact far-infrared sources in OMC-2 are found to be lower than the brightness temperature of the extended (C-12)O emission, indicating an important role in (C-12)O heating for stars external to the compact center.
A carbon rod furnace infrared source has been built and has proven to be a reliable and trouble-free source despite the high rod temperature of 2500 K. The furnace offers several advantages over previous furnaces. These include an increase in usable rod length to 6.35 cm, extended rod life, and a fully automated power supply for the furnace. Construction and operational details are discussed.
Inexpensive hand-held source of infrared energy is provided by a flashlight bulb coated with a paint which filters out the visible light emitted by the bulb and transmits only infrared radiation. This device can be used for checking infrared sensors and for experimental purposes.
Recent radio, infrared, and H2O maser observations show that there is a 7-arcsec angular separation between the protostarlike infrared source CRL 2591 and the compact H II region which has until now been identified with it, while the H2O maser coincides with the infrared source. This result, together with an extension of photometric measurements to 20 microns and a much improved upper limit to its angular size, reinforces the apparent similarity of CRL 2591 to the BN object in Orion and to W3/IRS 5.
In a survey of the W31 region, a compact far-infrared source was detected at the position of the radio continuum source G 10.6-0.4. Associated with this infrared source and in close coincidence with its position is an H II region with a compact core and extended halo as well as OH and H2O masers. An extended molecular cloud, centered on these sources, has also been detected. The compact source and associated masers may be located at the H II region-molecular-cloud interface in a thin shocked layer of neutral gas driven into the molecular cloud by the expansion of the H II region. The compact H II region is depleted of dust and must be surrounded by a very dense shell of dust and gas (hydrogen number density in excess of 200,000 per cu cm). The source probably represents an early stage of stellar evolution.
Source of pulsed infrared radiation for testing arrays of thermophotovoltaic cells obtained by placing infrared band-pass filter in front of large-area pulsed solar simulator (LAPSS). Source provides infrared radiation within required infrared spectral region, at required intensity and approximate spatial uniformity, over minimum area of 4 by 4 inches (10 by 10 centimeters).