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The SPIRE FTS Spectral Feature Finder (FF), developed within the Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) instrument team, is an automated spectral feature fitting routine that attempts to find significant features in SPIRE FTS spectra. The $^3$P$_1$ - $^3$P$_0$ and $^3$P$_2$ - $^3$P$_1$ neutral carbon fine structure lines are common features in carbon rich far-infrared astrophysical sources. These features can be difficult to detect using an automated feature detection routine due to their typically low amplitude and line blending. In this paper we describe and validate the FF sub-routine designed to detect the neutral carbon emission observed in SPIRE spectral data., 8 pages, 9 figures, 2 tables, final version accepted by MNRAS June 2020

This is the Reproduction package for the scientific article entitled "Modelling the Partially Coherent Behaviour of Few-Mode Far-Infrared Grating Spectrometers".

arXiv:2103.03584v1, We use the SPace Infrared telescope for Cosmology and Astrophysics (SPICA) project as a template to demonstrate how deep spectrophotometric surveys covering large cosmological volumes over extended fields (1–15 deg2) with a mid-IR imaging spectrometer (17–36 µm) in conjunction with deep photometry with a far-IR camera, at wavelengths which are not affected by dust extinction can answer the most crucial questions in current galaxy evolution studies. A SPICA-like mission will be able for the first time to provide an unobscured three-dimensional (3D, i.e. x, y, and redshift z) view of galaxy evolution back to an age of the universe of less than ∼ 2 Gyrs, in the mid-IR rest frame. This survey strategy will produce a full census of the Star Formation Rate (SFR) in the universe, using polycyclic aromatic hydrocarbons (PAH) bands and fine-structure ionic lines, reaching the characteristic knee of the galaxy luminosity function, where the bulk of the population is distributed, at any redshift up to z ∼ 3.5. Deep follow-up pointed spectroscopic observations with grating spectrometers onboard the satellite, across the full IR spectral range (17–210 µm), would simultaneously measure Black Hole Accretion Rate (BHAR), from high-ionisation fine-structure lines, and SFR, from PAH and low- to mid-ionisation lines in thousands of galaxies from solar to low metallicities, down to the knee of their luminosity functions. The analysis of the resulting atlas of IR spectra will reveal the physical processes at play in evolving galaxies across cosmic time, especially its heavily dust-embedded phase during the activity peak at the cosmic noon (z ∼ 1–3), through IR emission lines and features that are insensitive to the dust obscuration., LS and JAFO acknowledge financial support by the Agenzia Spaziale Italiana (ASI) under the research contract 2018-31-HH.0. AAH acknowledges support from grants PGC2018-094671-B-I00 (MCIU/AEI/FEDER,UE) and No. MDM-2017-0737 at Unidad de Excelencia María de Maeztu-Centro de Astrobiología (INTACSIC). FJC acknowledges financial support from the Spanish Ministry MCIU under project RTI2018-096686-B-C21 (MCIU/AEI/FEDER/UE), cofunded by FEDER funds and from the Agencia Estatal de Investigación, Unidad de Excelencia María de Maeztu, ref. MDM-2017-0765. HD acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under the 2014 Ramón y Cajal program RYC-2014-15686 and AYA2017-84061-P, the later one co-financed by FEDER (European Regional Development Funds). AL acknowledges the support from Comunidad de Madrid through the Atracción de Talento grant 2017-T1/TIC-5213. MPS acknowledges support from the Comunidad de Madrid, Spain, through Atracción de Talento Investigador Grant 2018-T1/TIC-11035.

This paper discusses the development of a cryogenic grating spectrometer that has been used to evaluate the performance of a post-dispersed polarizing FTS over the range of 285-500 µm.

The performance of a prototype far-infrared post-dispersed polarizing FTS has been measured using a source module consisting of unresolved emission and absorption lines and the results are compared with theoretical simulations.

We present some of the data processing challenges for a post-dispersed Fourier transform spectrometer and describe the techniques that were used to overcome them.

Post-dispersed Fourier transform spectrometers are prime candidates for up- coming far-infrared space telescopes, which achieve background limited spectral sensitivity by few-mode detectors. Straylight effects in such hybrid systems are investigated using a partially coherent modelling technique.

We describe the engineering development unit of a novel cryogenic scan mechanism suitable for post-dispersed polarizing FTS instruments. Compliance to the stringent SPICA mission requirements is demonstrated through analyses and results from proof-of- concept activities.

This paper describes the development and status of a cryogenic, far-infrared, post- dispersed, polarizing FTS (PDPFTS), a candidate instrument concept for the next generation of far- infrared astronomical space telescopes.

The mid/far infrared hosts a wealth of spectral information that allows direct determination of the physical state of matter in a large variety of astronomical objects, unhindered by foreground obscuration. Accessing this domain is essential for astronomers to much better grasp the fundamental physical processes underlying the evolution of many types of celestial objects, ranging from protoplanetary systems in our own milky way to 10-12 billion year old galaxies at the high noon of galaxy formation in our universe. The joint ESA/JAXA SPICA mission will give such access for the astronomical community at large, by providing an observatory with unprecedented mid- to far-infrared imaging, polarimetric and spectroscopic capabilities.

The continued improvement in the sensitivity of superconducting far-infrared bolometers necessitates improved designs of cryogenically cooled broadband spectrometers in order to fully exploit the potential of such detectors. While Fourier transform spectrometers (FTS) have an illustrious history in astronomical research, the sensitivity of state-of-the-art detectors is such that the multiplex disadvantage of FTS is prohibitive unless the spectral bandpass can be restricted to less than 1%. One method of achieving this goal, and the one that has been adopted for the SPICA SAFARI instrument, is to use a diffraction grating as the post-dispersing component. Unlike a typical FTS, in which a single detector simultaneously measures a broad spectral band, a post-dispersed detection system requires multiple detectors, each with their own unique spectral, spatial, and temporal responses. Moreover, the narrow spectral band viewed by each detector results in an interferogram having a large coherence length; the signal is heavily modulated, yet truncated. While simulations play a useful role in modeling instrumental performance, there is no substitute for data obtained from a real implementation of an instrument concept. In this paper we describe the development and current status of a cryogenic, far-infrared, postdispersed, polarizing FTS (PDPFTS): a demonstrator for the SPICA SAFARI instrument.

The optical modelling of far-infrared partially-coherent grating spectrometers has long been considered difficult, due to the multi-mode diffractive nature of the grating optics. However, for the next generation of far-infrared space missions the need for understanding the complex behaviour of these grating spectrometers has intensified. Conventional modelling techniques are difficult to apply because i) the field is partially coherent; ii) diffraction and focusing effects are crucially important; iii) diffraction integrals need to be sampled finely over large optical surfaces. We describe an effective approach based on propagating the correlation functions of the radiation field using the natural modes of the optical system. First, the transformation matrix of the system, T, is determined, which captures the natural modes of the optics. Next, the correlations functions are propagated through the optics using T. The result is a modal optics technique that captures all performance information, in terms of the spectral, spatial and coherence details, within a single framework. In the paper, we explain the foundations of the method and demonstrate its applicability based on a number of standard far-infrared optical systems. Our scheme is numerically powerful, and provides insights into the trade-offs needed to optimise performance. The analysis we will extended to partially coherent far-infrared grating spectrometers as a function of the incident spectral field compositions, scattering at the grating optics, and detector geometry to improve our understanding of such systems.

The high spectral resolution mode of the SpicA FAR-infrared Instrument (SAFARI) is enabled by inserting a Fourier Transform Spectrometer (FTS), based on a Martin-Puplett interferometer, into the signal path of the instrument. The cryogenic mechanism (FTSM) enables linear scans of two back-to-back rooftop mirrors sharing a common apex. ABB Inc. is under contract with the Canadian Space Agency to develop and test at 4 K an FTSM Engineering Demonstration Unit (EDU) for TRL-5 demonstration. The main SAFARI FTSM performance drivers are the stringent mechatronic demands (position stability of roof-top mirrors

Far-infrared spectroscopic observations of the universe provide a unique means of addressing some of the leading questions in modern astrophysics from the formation of stars and planets in our own galaxy to the evolution of galaxies over cosmic time. The technique of Fourier transform spectroscopy, with its ability to cover a broad spectral range at varying spectral resolution, has played a central role in such observations. The history of Fourier transform spectroscopy is reviewed and the evolving role of this technique in the era of photon counting infrared detectors discussed.

Recent advances in far-infrared detector technology have led to increases in raw sensitivity of more than an order of magnitude over previous state-of-the-art detectors. With such sensitivity, photon noise becomes the dominant noise component, even when using cryogenically cooled optics, unless a method of restricting the spectral bandpass is employed. One method is to use a low-resolution diffraction grating spectrometer to post-disperse the signal from a high-resolution instrument, such as a Fourier transform spectrometer (FTS). This concept has been adopted for the SAFARI instrument on the SPICA mission. This paper discusses the development of a prototype cryogenic grating spectrometer that has been used to evaluate the concept of a post-dispersed polarizing FTS over the range from 285-500 μm.

The sensitivity of state-of-the-art superconducting far-infrared (FIR) detectors is such that wideband spectroscopic observations, particularly those employing Fourier transform spectrometers (FTS), will require techniques to reduce the spectral bandwidth of a detector to limit the photon noise from an astronomical source. The proposed SPICA SAFARI instrument employs grating spectrometers to post-disperse the light that has been modulated by a polarizing FTS onto a detector array, thereby reducing the photon noise on each detector. While the principles of this method are understood, to date an integrated system has not been realized in the laboratory. We present the development of a FIR post-dispersed polarizing FTS (PDPFTS) consisting of a warm FTS and a 4 K grating spectrometer as a first step to a fully cryogenic PDPFTS demonstrator. Realistic astronomical spectra are generated by combining line emission from a tunable THz photomixer source with continuum emission from a variable blackbody source.

The sensitivity of state-of-the-art superconducting far-infrared detectors used in conjunction with cryogenically cooled space telescopes and instrumentation is such that spectroscopic observations are generally limited by photon noise from the astronomical source or by galactic foreground or zodiacal emission within the field-of-view. Therefore, an instrument design that restricts the spectral bandpass viewed by the detector must be employed. One method of achieving background limited, high resolution spectroscopy is to combine a high resolution component such as a Fabry-Pérot interferometer (FPI) with a lower resolution, post-dispersing system, such as a grating spectrometer, the latter serving to restrict the spectral bandpass. The resonant wavelength of an FPI is most often tuned by changing the spacing or medium between the parallel reflecting plates of the etalon. In this paper, we present a novel design for an FPI in which the wavelength is tuned by scanning the angle of incidence on a high refractive index etalon. This concept simplifies the cryomechanical design, actuation, and metrology. The first results from the realized instrument are presented and compared with theory. The effects on the spectral response as a function of the incident angle have been simulated and shown to agree well with the observation.

The ESA Herschel Spectral and Photometric Imaging Receiver (SPIRE) Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF) project is an automated spectral feature fitting routine developed within the SPIRE instrument team to extract all prominent spectral features from all publicly available SPIRE FTS observations. We present the extension of the FF to include the off-axis detectors of the FTS in sparsely sampled single-pointing observations, the results of which have been ingested into the catalogue. We also present the results from an automated routine for identifications of the atomic/molecular transitions that correspond to the spectral features extracted by the FF. We use a template of 307 atomic fine structure and molecular lines that are commonly found in SPIRE FTS spectra for the cross-match. The routine makes use of information provided by the line identification to search for low signal-to-noise ratio features that have been excluded or missed by the iterative FF. In total, the atomic/molecular transitions of 178,942 lines are identified (corresponding to 83% of the entire FF catalogue), and an additional 33,840 spectral lines associated with missing features from SPIRE FTS observations are added to the FF catalogue., 15 pages (+2 appendix pages), 14 figures, 7 tables, final version accepted by MNRAS June 2020

We provide a detailed description of the Herschel-SPIRE Fourier Transform Spectrometer (FTS) Spectral Feature Finder (FF). The FF is an automated process designed to extract significant spectral features from SPIRE FTS data products. Optimising the number of features found in SPIRE-FTS spectra is challenging. The wide SPIRE-FTS frequency range (447-1568 GHz) leads to many molecular species and atomic fine structure lines falling within the observed bands. As the best spectral resolution of the SPIRE-FTS is ~1.2 GHz, there can be significant line blending, depending on the source type. In order to find, both efficiently and reliably, features in spectra associated with a wide range of sources, the FF iteratively searches for peaks over a number of signal-to-noise ratio (SNR) thresholds. For each threshold, newly identified features are rigorously checked before being added to the fitting model. At the end of each iteration, the FF simultaneously fits the continuum and features found, with the resulting residual spectrum used in the next iteration. The final FF products report the frequency of the features found and the associated SNRs. Line flux determination is not included as part of the FF products, as extracting reliable line flux from SPIRE-FTS data is a complex process that requires careful evaluation and analysis of the spectra on a case-by-case basis. The FF results are 100% complete for features with SNR greater than 10 and 50-70% complete at SNR of 5. The FF code and all FF products are publicly available via the Herschel Science Archive., Comment: 20 pages, 8 figures, 8 tables, final version accepted by MNRAS June 2020

The most intensively star-forming galaxies are extremely luminous at far-infrared (FIR) wavelengths, highly obscured at optical and ultraviolet wavelengths, and lie at $z\ge 1-3$. We present a programme of ${\it Herschel}$ FIR spectroscopic observations with the SPIRE FTS and photometric observations with PACS, both on board ${\it Herschel}$, towards a sample of 45 gravitationally lensed, dusty starbursts across $z\sim 1-3.6$. In total, we detected 27 individual lines down to 3-$\sigma$, including nine $[\rm C{\small II}]$ 158-$\mu$m lines with confirmed spectroscopic redshifts, five possible $[\rm C{\small II}]$ lines consistent with their far-infrared photometric redshifts, and in some individual sources a few $[\rm O{\small III}]$ 88-$\mu$m, $[\rm O{\small III}]$ 52-$\mu$m, $[\rm O{\small I}]$ 145-$\mu$m, $[\rm O{\small I}]$ 63-$\mu$m, $[\rm N{\small II}]$ 122-$\mu$m, and OH 119-$\mu$m (in absorption) lines. To derive the typical physical properties of the gas in the sample, we stack all spectra weighted by their intrinsic luminosity and by their 500-$\mu$m flux densities, with the spectra scaled to a common redshift. In the stacked spectra, we detect emission lines of $[\rm C{\small II}]$ 158-$\mu$m, $[\rm N{\small II}]$ 122-$\mu$m, $[\rm O{\small III}]$ 88-$\mu$m, $[\rm O{\small III}]$ 52-$\mu$m, $[\rm O{\small I}]$ 63-$\mu$m, and the absorption doublet of OH at 119-$\mu$m, at high fidelity. We find that the average electron densities traced by the $[\rm N{\small II}]$ and $[\rm O{\small III}]$ lines are higher than the average values in local star-forming galaxies and ULIRGs, using the same tracers. From the $[\rm N{\small II}]/[\rm C{\small II}]$ and $[\rm O{\small I}]/[\rm C{\small II}]$ ratios, we find that the $[\rm C{\small II}]$ emission is likely dominated by the photo-dominated regions (PDR), instead of by ionised gas or large-scale shocks., Comment: 39 pages, 19 figures, Accepted for publication in MNRAS. For extra pptx slides prepared for this work, please see http://www.eso.org/~zzhang/download/FTS_SMG_survey_ZhiyuZhang.pdf

The sensitivity of state-of-the-art superconducting far-infrared detectors is such that astronomical observations at these wavelengths are limited by photon noise from the astronomical source unless a method of restricting the spectral bandpass is employed. One such method is to use a high resolution Fabry-Perot interferometer (FPI) in conjunction with a lower resolution, post-dispersing system, such as a grating spectrometer. The resonant wavelength of an FPI is typically tuned by changing the spacing or medium between the parallel reflecting plates of the etalon. We previously reported on a novel design in which the wavelength is tuned by scanning the angle of incidence, which simplifies the cryo-mechanical design, actuation and metrology. Here we present first light results from the realized instrument.

The SPIRE Fourier Transform Spectrometer on board the Herschel Space Observatory had two standard spectral resolution modes for science observations: high resolution (HR) and low resolution (LR), which could also be performed in sequence (H+LR). A comparison of the HR and LR resolution spectra taken in this sequential mode, revealed a systematic discrepancy in the continuum level. Analysing the data at different stages during standard pipeline processing, demonstrates the telescope and instrument emission affect HR and H+LR observations in a systematically different way. The origin of this difference is found to lie in the variation of both the telescope and instrument response functions, while it is triggered by fast variation of the instrument temperatures. As it is not possible to trace the evolution of the response functions through auxiliary housekeeping parameters, the calibration cannot be corrected analytically. Therefore an empirical correction for LR spectra has been developed, which removes the systematic noise introduced by the variation of the response functions., 13 pages, 17 figures, 4 tables. Accepted for publication in MNRAS

The initiation and maintenance phases of cholinergic status epilepticus (SE) are associated with maladaptive trafficking of synaptic GABAA and glutamate receptors. The resulting pharmacoresistance reflects a decrease in synaptic GABAA receptors and increase in NMDA and AMPA receptors, which tilt the balance between inhibition and excitation in favor of the latter. If these changes are important to the pathophysiology of SE, both should be treated, and blocking their consequences should have therapeutic potential. We used a model of benzodiazepine-refractory SE (RSE) (Tetz et al., 2006) and a model of soman-induced SE to test this hypothesis. Treatment of RSE with combinations of the GABAAR agonists midazolam or diazepam and the NMDAR antagonists MK-801 or ketamine terminated RSE unresponsive to high-dose monotherapy with benzodiazepines, ketamine or other antiepileptic drugs (AEDs). It also reduced RSE-associated neuronal injury, spatial memory deficits and the occurrence of spontaneous recurrent seizures (SRS), tested several weeks after SE. Treatment of sc soman-induced SE similarly showed much greater reduction of EEG power by a combination of midazolam with ketamine, compared to midazolam monotherapy. When treating late (40 min after seizure onset), there may not be enough synaptic GABAAR left to be able to restore inhibition with maximal GABAAR stimulation, and further benefit is derived from the addition of an AED which increases inhibition or reduces excitation by a non-GABAergic mechanism. The midazolam-ketamine-valproate combination is effective in terminating RSE. 3-D isobolograms demonstrate positive cooperativity between midazolam, ketamine and valproate, without any interaction between the toxicity of these drugs, so that the therapeutic index is increased by combination therapy between GABAAR agonist, NMDAR antagonist and selective AEDs. We compared this drug combination based on the receptor trafficking hypothesis to treatments based on clinical practice. The midazolam-ketamine-valproate combination is far more effective in stopping RSE than the midazolam-fosphenytoin-valproate combination inspired from clinical guidelines. Furthermore, sequential administration of midazolam, ketamine and valproate is far less effective than simultaneous treatment with the same drugs at the same dose. These data suggest that we should re-evaluate our traditional treatment of RSE, and that treatment should be based on pathophysiology. The search for a better drug has to deal with the fact that most monotherapy leaves half the problem untreated. The search for a better benzodiazepine should acknowledge the main cause of pharmacoresistance, which is loss of synaptic GABAAR. Future clinical trials should consider treating both the failure of inhibition and the runaway excitation which characterize RSE, and should include an early polytherapy arm.

Over half of the light incident on the Earth from the Universe falls within the Far-Infrared (FIR) region of the spectrum. Due to the deleterious effects of the Earth's atmosphere and instrument self-emission, astronomical measurements in the FIR require space-borne instrumentation operating at cryogenic temperatures. These instruments place stringent constraints on the mechanical and thermal properties of the support structures at low temperatures. With high stiffness, tensile strength, strength-to-mass ratio, and extremely low thermal conductivity, carbon fibre reinforced polymers (CFRPs) are an important material for aerospace and FIR astronomical applications, however, little is known about their properties at cryogenic temperatures. We have developed a test facility for exploring CFRP properties down to 4 K. We present results from our ongoing study in which we compare and contrast the performance of CFRP samples using different materials, and multiple layup configurations. Current results include an evaluation of a cryostat dedicated for materials testing and a custom cryogenic metrology system, and preliminary cryogenic thermal expansion measurements. The goal of this research is to explore the feasibility of making CFRP-based, lightweight, cryogenic astronomical instruments.

Measurements in the infrared wavelength domain allow us to assess directly the physical state and energy balance of cool matter in space, thus enabling the detailed study of the various processes that govern the formation and early evolution of stars and planetary systems in the Milky Way and of galaxies over cosmic time. Previous infrared missions, from IRAS to Herschel, have revealed a great deal about the obscured Universe, but sensitivity has been limited because up to now it has not been possible to fly a telescope that is both large and cold. Such a facility is essential to address key astrophysical questions, especially concerning galaxy evolution and the development of planetary systems. SPICA is a mission concept aimed at taking the next step in mid- and far-infrared observational capability by combining a large and cold telescope with instruments employing state-of-the-art ultra-sensitive detectors. The mission concept foresees a 2.5-meter diameter telescope cooled to below 8 K. Rather than using liquid cryogen, a combination of passive cooling and mechanical coolers will be used to cool both the telescope and the instruments. With cooling not dependent on a limited cryogen supply, the mission lifetime can extend significantly beyond the required three years. The combination of low telescope background and instruments with state-of-the-art detectors means that SPICA can provide a huge advance on the capabilities of previous missions. The SPICA instrument complement offers spectral resolving power ranging from ~50 through 11000 in the 17-230 µm domain as well as ~28.000 spectroscopy between 12 and 18 µm. Additionally, SPICA will be capable of efficient 30-37 µm broad band mapping, and small field spectroscopic and polarimetric imaging in the 100-350 µm range. SPICA will enable far infrared spectroscopy with an unprecedented sensitivity of ~5x10-20 W/m2 (5σ/1hr) - at least two orders of magnitude improvement over what has been attained to date. With this exceptional leap in performance, new domains in infrared astronomy will become accessible, allowing us, for example, to unravel definitively galaxy evolution and metal production over cosmic time, to study dust formation and evolution from very early epochs onwards, and to trace the formation history of planetary systems.

The European/Japanese SPace Infrared telescope for Cosmology and Astrophysics, SPICA, will provide astronomers with a long awaited new window on the universe. Having a large cold telescope cooled to less than 8K above absolute zero, SPICA will provide a unique environment where instruments are limited only by the cosmic background itself. A consortium of European, north American and Asian institutes has been established to design and implement the SpicA FAR infrared Instrument SAFARI, an extremely sensitive spectrometer designed to fully exploit this extremely low far infrared background environment provided by the SPICA observatory. SAFARI’s extremely sensitive Transition Edge Sensing detectors will allow astronomers to very efficiently obtain moderate to high resolution spectra of many thousands of obscured celestial objects in the far infrared, allowing a full spectroscopic characterisation of this objects. Efficiently obtaining such a large number of complete spectra will be essential to address several fundamental questions in current astrophysics: how do galaxies form and evolve over cosmic time?, what is the true nature of our own Milky Way?, and why and where do planets like those in our own solar system come into being? The basic SAFARI instrument is a highly sensitive Grating Spectrometer with a spectral resolution R of about 300 and a line sensitivity of a few x 10^-20 W/√Hz (5σ-1h). By routing the signal through a Martin-Puplett interferometer a high resolution mode is implemented providing R~11000 at 34 μm to R~1500 at 230 μm. The instrument operates in four wavelength bands, simultaneously covering the full 34-230μm range. Each band has three arrays of about 300 TES sensors providing three spatial and 300 spectral outputs. To limit the number of signal wires between the cold focal plan and the warm electronics units a 160 pixel/channel Frequency Domain Multiplexing scheme is employed.

We present the design and performance of a cryogenic, angle-scanned Fabry-Perot interferometer for far infrared astronomical spectroscopy. Novel features of the design are discussed, and the spectral response of the instrument is modeled. Experimental methods being developed to validate the spectral response are presented.

We describe an update to the Herschel-SPIRE Fourier-Transform Spectrometer (FTS) calibration for extended sources, which incorporates a correction for the frequency-dependent far-field feedhorn efficiency, $\eta_\mathrm{FF}$. This significant correction affects all FTS extended-source calibrated spectra in sparse or mapping mode, regardless of the spectral resolution. Line fluxes and continuum levels are underestimated by factors of 1.3-2 in the Spectrometer Long-Wavelength band (SLW, 447-1018 GHz; 671-294 $\mu$m) and 1.4-1.5 in the Spectrometer Short-Wavelength band (SSW, 944-1568 GHz; 318-191 $\mu$m). The correction was implemented in the FTS pipeline version 14.1 and has also been described in the SPIRE Handbook since Feb 2017. Studies based on extended-source calibrated spectra produced prior to this pipeline version should be critically reconsidered using the current products available in the Herschel Science Archive. Once the extended-source calibrated spectra are corrected for $\eta_\mathrm{FF}$, the synthetic photometry and the broadband intensities from SPIRE photometer maps agree within 2-4% -- similar levels to the comparison of point-source calibrated spectra and photometry from point-source calibrated maps. The two calibration schemes for the FTS are now self-consistent: the conversion between the corrected extended-source and point-source calibrated spectra can be achieved with the beam solid angle and a gain correction that accounts for the diffraction loss., Comment: 9 pages, 6 figures, 1 table, MNRAS in press

Nature is such that observations at far-infrared wavelengths are optimal for exploring both the nearby and distant Universe. The minute amount of energy carried by far-infrared photons, however, requires extremely sensitive instrumentation for their detection. Moreover, the instrumentation itself must be cooled to

We present an analysis of the updated publicly available Herschel SPIRE spectral Feature Finder data products, focusing primarily on mapping observations, radial velocity estimates, and neutral carbon detection.

The far-infrared spectrometer SAFARI is one of the three scientific instruments on the SPICA mission, a joint European-Japanese project, which was recently selected as one of the three mission candidates for further study in ESA's M5 call. SPICA employs a 2.5m large telescope deeply cooled to below 8K, improving sensitivities by more than two orders of magnitude with respect to Herschel and Spitzer, filling in the spectral gap between JWST, ELT and ALMA. SAFARI will provide unprecedented spectroscopic observing capabilities in the far-infrared targeting the physical processes governing the formation and evolution of galaxies over cosmic time, and of planetary systems.SAFARI will provide limiting line sensitivities of order of a few times 10--20 W/m2 (5$-10hr) instantaneously covering the 34-230 textmum wavelength range. The extremely high sensitivity of the instrument is realized by utilization of TES detector arrays distributed over four grating modules, offering a native spectral resolving power of 300. The high-resolution spectroscopy mode of the instrument is carefully designed around a post-dispersed Martin-Puplett polarizing interferometer yielding R up to 11000 at the short wavelength limit. The cryogenic translation mechanism in the heart of the FTS spectrometer layout, presents challenging development goals within the context of SAFARI, and is provided by a Canadian consortium sponsored by the CSA.In this paper we provide a comprehensive overview of the instrument architecture and key technologies currently baselined for the subsystems, units and components of SAFARI. We will present the rationale of the FTS architecture employing a MP interferometer as the best way to meet the high-resolution spectroscopic and sensitivity requirements of SAFARI, and we will discuss the different spectroscopic modes in which the instrument can be configured. We conclude the paper by discussing the projected instrument performance and spectroscopic characteristics in view of the scientific goals.

The SPICA mission will employ ultra-sensitive superconducting detectors. In this case the multiplex disadvantage of Fourier transform spectroscopy dictates the use of a post-dispersed, diffraction grating detection system. The challenges of reconstructing astronomical spectra will be reviewed.

The high resolution spectroscopic mode of the SPICA SAFARI instrument will be achieved using a Martin-Puplett interferometer. The key science and technology requirements of the spectrometer will be reviewed and the current instrumental concept presented.

Characterization results are presented for a double-Fourier spatial/spectral laboratory interferometer. This instrument is a testbed platform for developing imaging techniques, data processing algorithms, and component characterization for space-based astronomical applications in the far-infrared.

著者人数: 70名(所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 芝井, 広; 船木, 一幸; 磯部, 直樹; 川田, 光伸; 權, 靜美; 松原, 英雄; 中川, 貴雄; 小川, 博之; 佐藤, 洋一; 篠崎, 慶亮; 杉田, 寛之; 和田, 武彦; 山田, 亨; 山村, 一誠), Number of authors: 70(Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS): Shibai, Hiroshi; Funaki, Ikkoh; Isobe, Naoki; Kawada, Mitsunobu; Kwon, Jungmi; Matsuhara, Hideo; Nakagawa, Takao; Ogawa, Hiroyuki; Sato, Yoichi; Shinozaki, Keisuke; Sugita, Hiroyuki; Wada, Takehiko; Yamada, Toru; Yamamura, Issei), 資料番号: SA1180106000