FLEX low resolution spectrometer breadboard activities

The spectra of the IRAS low-resolution-spectrometer in tape form have been submitted to a systematic morphological analysis, using classical quantitative discriminants (O.Gal et al. 1987, A & A 183, 29; Y. Baron et al. 1987, A & A 186, 271; R. Papoular 1988, A & A , in press). Spectra which display the 11.5μ feature of SiC fall into 4 classes of average spectral excesses. They differ by the width of the SiC feature and by the presence or absence of secondary features at ~8.6, ~11.7 and ~12.8μm.A majority of these spectra have a lower 12-25μm colour temperature than do most optically selected C-stars, presumably because of thicker dust envelopes. While most spectra belong to LRS class 4n, 20% of the total were found among the brightest 20% of the much larger class In, suggesting that the relative abundance of C-stars is much higher than previously assumed.

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An IRAS-based search for new dusty WCL Wolf-Rayet stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900202301 ◽

1995 ◽

Vol 163 ◽

pp. 359-362

Author(s):

Martin Cohen

Keyword(s):

Point Source ◽

Optical Spectroscopy ◽

Infrared Astronomy ◽

Low Resolution ◽

Full Resolution ◽

Resolution Spectrometer ◽

Colour Indices ◽

Point Source Catalog

I have examined all InfraRed Astronomy Satellite (IRAS) data relevant to the 173 galactic Wolf-Rayet (WR) stars in an updated catalogue provided by van der Hucht (priv. comm.), including the 13 stars newly discovered by Shara et al. (1991). Using the exact coordinates given in these lists, I have examined the IRAS Point Source Catalog (PSC), the Faint Source Catalog, Faint Source Reject Catalog, and generated 1-dimensional spatial profiles (“ADDSCAN”s), and 2-dimensional full-resolution images (“FRESCO”s). The goal was to assemble the best set of observed IRAS colour indices for different WR types, in particular for known dusty WCL objects. These colour indices define zones in the IRAS colour-colour plane. By searching the PSC for otherwise unassociated sources that satisfy these colours, I have identified potential new WR candidates, too faint to have been recognized in previous optical searches. I have extracted these candidates' IRAS Low Resolution Spectrometer (LRS) data and compared the spectra with the highly characteristic LRS shape for known dusty WCL stars. Any surviving candidates must now be examined by optical spectroscopy. This work represents a much more rigorous and exhaustive version of the LRS study that identified IRAS 17380-3031 (WR98a) as the first new WR (WC9) star discovered by IRAS (Cohen et al. 1991).

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A wide field-of-view low-resolution spectrometer at APEX: Instrument design and scientific forecast

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038456 ◽

2020 ◽

Vol 642 ◽

pp. A60

Author(s):

◽

P. Ade ◽

M. Aravena ◽

E. Barria ◽

A. Beelen ◽

...

Keyword(s):

Instrument Design ◽

Field Of View ◽

Large Field ◽

Kinetic Inductance Detectors ◽

Kinetic Inductance ◽

Base Temperature ◽

Low Resolution ◽

Intensity Mapping ◽

The Universe ◽

Resolution Spectrometer

Context. Characterising the large-scale structure in the Universe from present times to the high redshift epoch of reionisation is essential to constraining the cosmology, the history of star formation, and reionisation, to measuring the gas content of the Universe, and to obtaining a better understanding of the physical processes that drive galaxy formation and evolution. Using the integrated emission from unresolved galaxies or gas clouds, line intensity mapping (LIM) provides a new observational window to measure the larger properties of structures. This very promising technique motivates the community to plan for LIM experiments. Aims. We describe the development of a large field-of-view instrument, named CONCERTO (for CarbON CII line in post-rEionisation and ReionisaTiOn epoch), operating in the range 130–310 GHz from the APEX 12-m telescope (5100 m above sea level). CONCERTO is a low-resolution spectrometer based on the lumped element kinetic inductance detectors (LEKID) technology. Spectra are obtained using a fast Fourier transform spectrometer (FTS), coupled to a dilution cryostat with a base temperature of 0.1 K. Two two kilo-pixel arrays of LEKID are mounted inside the cryostat that also contains the cold optics and the front-end electronics. Methods. We present, in detail, the technological choices leading to the instrumental concept, together with the design and fabrication of the instrument and preliminary laboratory tests on the detectors. We also give our best estimates for CONCERTO sensitivity and give predictions for two of the main scientific goals of CONCERTO, that is, a [CII]-intensity mapping survey and observations of galaxy clusters. Results. We provide a detailed description of the instrument design. Based on realistic comparisons with existing instruments developed by our group (NIKA, NIKA2, and KISS), and on the laboratory characterisation of our detectors, we provide an estimate for CONCERTO sensitivity on the sky. Finally, we describe, in detail, two of the main scientific goals offered by CONCERTO at APEX.

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