Spectrograph

CARMENES is the new high-resolution high-stability spectrograph built for the 3.5m telescope at the Calar Alto Observatory (CAHA, Almería, Spain) by a consortium formed by German and Spanish institutions. This instrument is composed by two separated spectrographs: VIS channel (550-1050 nm) and NIR channel (950-1700 nm). The NIR-channel spectrograph's responsible institution is the Instituto de Astrofísica de Andalucía, IAA-CSIC. The contouring conditions have led CARMENES-NIR to be a schedule-driven project with a extremely tight plan. The operation start-up was mandatory to be before the end of 2015. This plays in contradiction to the very complex, calm-requiring tasks and development phases faced during the AIV, which has been fully designed and implemented at IAA through a very ambitious, zero-contingency plan. As a large cryogenic instrument, this plan includes necessarily a certain number cryo-vacuum cycles, this factor being the most important for the overall AIV duration. Indeed, each cryo-vacuum cycle of the NIR channel runs during 3 weeks. This plan has therefore been driven to minimize the amount of cryo-vacuum cycles. Such huge effort has led the AIV at system level at IAA lab to be executed in 9 months from start to end-an astonishingly short duration for a large cryogenic, complex instrument like CARMENES NIR-which has been fully compliant with the final deadline of the installation of the NIR channel at CAHA 3.5m telescope. The detailed description of this planning, as well as the way how it was actually performed, is the main aim of the present paper.

h i g h l i g h t s We analyze spectral time variations in two stars, FK Comae and V1794 Cygni. The emission lines fluxes for FK Com and V1794 Cyg vary by factors of $2-3. The fluxes of the C II, C IV, and He II lines of FK Com are comparable to V1794 Cyg. The variations are consistent with some models that have been previously proposed.

The National Science Foundation’sDaniel K. Inouye Solar Telescope(DKIST) will revolutionize our ability to measure, understand, and model the basic physical processes that control the structure and dynamics of the Sun and its atmosphere. The first-light DKIST images, released publicly on 29 January 2020, only hint at the extraordinary capabilities that will accompany full commissioning of the five facility instruments. With this Critical Science Plan (CSP) we attempt to anticipate some of what those capabilities will enable, providing a snapshot of some of the scientific pursuits that the DKIST hopes to engage as start-of-operations nears. The work builds on the combined contributions of the DKIST Science Working Group (SWG) and CSP Community members, who generously shared their experiences, plans, knowledge, and dreams. Discussion is primarily focused on those issues to which DKIST will uniquely contribute.

The study of surface activity on young solar-type stars provides an opportunity to improve understanding of stellar dynamos and indirectly gain insight into early solar evolution. Doppler Imaging (DI) can be used to map stellar surface activity, and utilises rotation-induced Doppler-broadening of spectral lines to calculate the surface distribution of a fundamental parameter such as temperature. DI requires high-resolution spectroscopic observations distributed over one or more stellar rotation periods. To date only a limited number of single young solar analogues have been observed using this technique. Observations of many stars at various evolutionary states and with varying physical parameters are necessary to comprehensively constrain stellar dynamo models. These observations require long-term access to a telescope with a high-resolution echelle spectrograph to undertake multiple epoch studies of stellar activity. This project has used the ANU 2.3 metre telescope to test Doppler Imaging with two active young stars, AB Doradus (AB Dor) and HIP43720, with the HIP43720 observations contemporaneous with the Anglo-Australian Telescope (AAT) observations. Analysis of the AB Dor mapping and comparison of the 2.3 metre and AAT results for HIP43720 indicates that the ANU 2.3 metre telescope with its high resolution echelle spectrograph is capable of undertaking scientifically useful Doppler Imaging for stellar dynamo surveys. iii Certification of Dissertation I certify that this dissertation contains no material accepted for the award of any other degree or diploma in any university. To the best of my knowledge, it contains no material published or written by another person, except where due reference is made in the text.

We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrograph's (NIRSpec's) detectors will be read out, and present a model of how noise scales with the number of multiple non-destructive reads samplingup-the-ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some non-ideal behaviors that have been observed in engineering grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is: (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.

Data from a pinhole camera and a transmission grating spectrograph are used in multi-TW laser irradiance of thin metal films to assess the maximum laser spot size and to show tenths of a percent conversion of laser light to K-, Land nd M-band x rays. The distribution of target debris, an operational issue for the survivability of an unshielded parabola in a large laser system, is revealed by x-ray fluorescence measurements of witness samples. At the 25-J, 30-TW level, we find little evidence of damage to the f/3 parabola with an angle of incidence on target greater than 22 • .

We present Gemini-South observations of nine faint and extended planetary nebulae. Using direct images taken with the spectrograph GMOS, we built the (u − g) vs. (g − r) diagrams of the stars in the observed areas which allowed us, also considering their geometrical positions, to identify the probable central stars of the nebulae. Our stellar spectra of seven stars, also taken with GMOS, indicate that four (and probably two more) objects are white dwarfs of the DAO subtype. Moreover, the white dwarf status of the four stars is confirmed by the parameters T eff and log g derived with the help of theoretical stellar spectra. Given this evidence, we propose that these hot stars are the central ionizing sources of the nebulae. With this work we hope to help improve the current scarce statistics on central white dwarfs in planetary nebulae.

The solar physics community is entering a golden era that is ripe with next-generation ground-and space-based facilities, advanced spectral inversion techniques, and realistic simulations that are becoming more computationally streamlined and efficient. With everincreasing resolving power stemming from the newest observational telescopes, it becomes more challenging to obtain (near-)simultaneous measurements at high spatial, temporal and spectral resolutions, while operating at the diffraction limit of these new facilities. Hence, in recent years there has been increased interest in the capabilities integral field units (IFUs) offer towards obtaining the trifecta of high spatial, temporal and spectral resolutions contemporaneously. To date, IFUs developed for solar physics research have focused on mid-optical and infrared measurements. Here, we present an IFU prototype that has been designed for operation within the near-ultraviolet to mid-optical wavelength range, which enables key spectral lines (e.g., Ca II H/K, Hβ, Sr II, Na I D 1 /D 2 , etc.) to be studied, hence providing additional spectral coverage to the instrument suites developed to date. The IFU was constructed as a low-budget proof-of-concept for the upcoming 2 m class Indian National Large Solar Telescope and employs circular cross-section fibres to guide light into a Czerny-Turner configuration spectrograph, with the resulting spectra captured using a high quantum efficiency scientific CMOS camera. Mapping of each input fibre allows for the reconstruction of two-dimensional spectral images, with frame rates exceeding 20 s −1 possible while operating in a non-polarimetric configuration. Initial commissioning of the instrument was performed at the Dunn Solar Telescope, USA, during August 2022. The science verification data presented here highlights the suitability of fibre-fed IFUs operating at near-ultraviolet wavelengths for solar physics research. Importantly, the successful demonstration of this type of instrument paves the way for further technological developments to make a future variant suitable for upcoming ground-based and space-borne telescope facilities.

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HARMONI is the first light visible and near-infrared (NIR) integral field spectrograph for the Extremely Large Telescope(ELT). The HARMONI spectrograph will have four near-infrared cameras and two visible, both with seven lenses of various materials and diameters ranging from 286 to 152 mm. The lens mounts design has been optimized for each lens material to compensate for thermal stresses and maintain lens alignment at the operational temperature of 130 K. We discuss their design and mounting concept, as well as assembly and verification steps. We show initial results from two prototypes and outline improvements in the mounting procedures to reach tighter lens alignments. To conclude, we present a description of our future work to measure the decentering of the lenses when cooled down and settled.

EMIR is a near-infrared, multi-slit camera-spectrograph under development for the 10m GTC on La Palma. It will deliver up to 45 independent R=3500-4000 spectra of sources over a field of view (FOV) of 6'x3', and allow NIR (Z, J, H, K) imaging over a 6'x6' FOV, with spatial sampling of 0.175"/pixel. The prime science goal of the instrument is to open Kband, wide field multi-object spectroscopy on 10m class telescopes. Science applications range from the study of starforming galaxies beyond z=2, to observations of substellar objects and dust-enshrouded star formation regions. Main technological challenges include the large optics, the mechanical and thermal stability and the need to implement a mask exchange mechanism that does not require warming up the spectrograph. EMIR is being developed by the

EMIR is a multiobject intermediate resolution near infrared (1.0-2.5 microns) spectrograph with image capabilities to be mounted on the 10m Gran Telescopio de Canarias (GTC), located on the Spanish island of La Palma. This paper shows an overview of the EMIR electronics and mechanism control. First, a description of the detector (a Hawaii-2 array) electronics is given, which involves the use of commercial components (resistors, capacitors and operational amplifiers) working under cryogenic conditions (around 77K). This paper describes the particularities of the cold electronics, showing the problems found and the way to solve them. Preliminary results of the detector characterization are also presented in this paper. Secondly, an overview of the different mechanisms of the instrument is presented. They are cryogenic mechanisms with pretty stringent positioning requirements. The technological solutions used to meet the tight control requirements will be described.

EMIR, currently entering into its fabrication and AIV phase, will be one of the first common user instruments for the GTC, the 10 meter telescope under construction by GRANTECAN at the Roque de los Muchachos Observatory (Canary Islands, Spain). EMIR is being built by a Consortium of Spanish and French institutes led by the Instituto de Astrofísica de Canarias (IAC). EMIR is designed to realize one of the central goals of 10m class telescopes, allowing observers to obtain spectra for large numbers of faint sources in an time-efficient manner. EMIR is primarily designed to be operated as a MOS in the K band, but offers a wide range of observing modes, including imaging and spectroscopy, both long slit and multiobject, in the wavelength range 0.9 to 2.5 µm. It is equipped with two innovative subsystems: a robotic reconfigurable multislit mask and disperssive elements formed by the combination of high quality difracction grating and conventional prisms, both at the heart of the instrument. The present status of development, expected performances, schedule and plans for scientific exploitation are described and discussed. The development and fabrication of EMIR is funded by GRANTECAN and the Plan Nacional de Astronomía y Astrofísica (National Plan for Astronomy and Astrophysics, Spain).

MOSAIC is a concept for a multi-object spectrograph for the Extremely Large Telescope (ELT). It is planned to cover the wavelength range from 460 nm to 1800 nm with two types of spectrographs, optimized for the visible and the near-infrared. There are two observing modes; multiplex mode with 200 sampling points and Integral Field Unit (IFU) mode with 10 fields. The instrument consists of 5 visible spectrographs and 5 near-infrared spectrographs. The ELT is far from diffraction limited in the visible wavelength range. Rather than developing a large and complex AO system, it was decided that the instrument will be seeing limited in the visible. Spot sizes are therefore about 2.8 mm in diameter in the ELT focal plane, and need to be sampled by multiple fibers with large core diameter. As a result, large optics is required to achieve the science requirements on spectral resolution, bandwidth and multiplex. We work in close collaboration with manufacturers to design an instrument that is feasible and meets the scientific requirements.

We report the results of a wide-field narrowband survey for redshift z ∼ 5.7 Lyα emitters carried out with the 34 ′ × 27 ′ field-of-view SuprimeCam mosaic CCD camera on the Subaru 8.3-m telescope. Deep narrowband imaging of the SSA22 field through a 120Å bandpass filter centered at a nominal wavelength of 8150Å was combined with deep multicolor RIz ′ broadband imaging with SuprimeCam, then supplemented with BV RZ imaging taken with the 42 ′ × 28 ′ field-of-view CFH12K camera on the Canada-France-Hawaii 3.6-m telescope to select high-redshift galaxy candidates. Spectroscopic observations were made using the new wide-field multi-object DEIMOS spectrograph on the 10-m Keck II Telescope for 22 of the 26 candidate objects. Eighteen of these objects were identified as z ∼ 5.7 Lyman alpha emitters, and a further nineteenth object from the candidate list was identified based on an LRIS spectrum. At the 3.3Å resolution of the DEIMOS observations the asymmetric profile for Lyα emission with its steep blue fall-off can be clearly seen in the spectra of the identified galaxies. This is by far the largest spectroscopic sample of galaxies at these redshifts, and we use it to describe the distribution of equivalent widths and continuum color break properties for identified Lyα galaxies compared with the foreground population. The large majority (at least 75%) of the lines have rest frame Lyα equivalent widths substantially less than 240Å and can be understood in terms of young star forming galaxies with a Salpeter initial mass function for the stars. With the narrowband selection criteria of (I − N) > 0.7 and N < 25.05 (AB mags) we find a surface density of Lyα emitters of 0.03 per square arcminute in the filter bandpass (∆z = 0.1) down to a limiting flux of just under 2 × 10 −17 erg cm −2 s −1. The luminosity function of the Lyα emitters is similar to that at lower redshifts to the lowest measurable luminosity of 10 43 erg s −1 as is the universal star formation rate based on their continuum properties. However, we note that the objects are highly structured in both their spatial and spectral properties on the angular scale of the fields (≈ 60 Mpc), and that multiple fields will have to be averaged to accurately measure their ensemble properties.

Context. We explore the stellar content of the Javalambre Photometric Local Universe Survey (J-PLUS) Data Release 2 and show its potential for identifying low-metallicity stars using the Stellar Parameters Estimation based on Ensemble Methods (SPEEM) pipeline. Aims. SPEEM is a tool used to provide determinations of atmospheric parameters for stars and separate stellar sources from quasars based on the unique J-PLUS photometric system. The adoption of adequate selection criteria allows for the identification of metal-poor star candidates that are suitable for spectroscopic follow-up investigations. Methods. SPEEM consists of a series of machine-learning models that use a training sample observed by both J-PLUS and the SEGUE spectroscopic survey. The training sample has temperatures, Teff, between 4800 K and 9000 K, values of log g between 1.0 and 4.5, as well as −3.1 &lt; [Fe/H] &lt; +0.5. The performance of the pipeline was tested with a sample of stars observed by the LAMOST survey...

A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument ...

We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrograph's (NIRSpec's) detectors will be read out, and present a model of how noise scales with the number of multiple non-destructive reads samplingup-the-ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some non-ideal behaviors that have been observed in engineering grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is: (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.

We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution (R = 30− 330) prism spectroscopy over the wavelength range 0.6 − 5.3µm and higher resolution (R = 500− 1340 or R = 1320− 3600) grating spectroscopy over 0.7 − 5.2µm, both in singleobject mode employing any one of five fixed slits, or a 3.1×3.2 arcsec 2 integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6×3.4 arcmin 2 field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed.

We are conducting a long-term project to observe a wide sample of cataclysmic variables with high resolution spectroscopy ( R ˜ 20000) using the echelle spectrograph at the 2.1 m telescope at the Observatorio Astronómico Nacional at San Pedro Mártir Observatory in Baja California, Mexico. Time series of a number of objects covering several orbital periods have been used to map their accretion disks using the Doppler tomography technique. We present preliminary results and discuss how can we take advantage of the GTC high resolution spectrograph to improve these kinds of observations.

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We have developed and standardized a novel hybrid laser-induced breakdown spectroscopy (LIBS)-Raman system using a single pulsed laser and a high-resolution intensified charge coupled device coupled echelle spectrograph. LIBS and Raman spectroscopy are highly complementary techniques which yield elemental and molecular information. Both techniques share an apparently similar instrumental configuration but need entirely different requirements like spectral range covered, resolution, and light-gathering efficiencies. There are thus many challenges to be faced in developing a combined system. In the present work, we show that an echelle spectrograph combined with a compact Q-switched Nd:YAG laser operating at 532 nm as an excitation source in a portable configuration can be efficiently used for such multi-purpose spectroscopy. Atomic and molecular emissions from the sample surface have been recorded in a gated mode using this setup. Compared to conventional spectrographs, echelle provi...

Context. Pulsars are well studied all over the electromagnetic spectrum, and the Crab pulsar may be the most studied object in the sky. Nevertheless, a high-quality optical to near-infrared (NIR) spectrum of the Crab or any other pulsar has not been published to date. Aims. Obtaining a properly flux-calibrated spectrum enables us to measure the spectral index of the pulsar emission, without many of the caveats from previous studies. This was the main aim of this project, but in addition we could also detect absorption and emission features from the pulsar and nebula over an unprecedentedly wide wavelength range. Methods. A spectrum was obtained with the X-shooter spectrograph on the Very Large Telescope. Special care was given to the flux-calibration of these data. Results. A high signal-to-noise spectrum of the Crab pulsar was obtained from 300 nm to 2400 nm. The spectral index fit to this spectrum is flat with α ν = 0.16 ± 0.07. For the emission lines we measured a maximum velocity of ∼1600 km s -1 , whereas the absorption lines from the material between us and the pulsar is unresolved at the ∼50 km s -1 resolution. A number of diffuse interstellar bands and a few NIR emission lines that have previously not been reported from the Crab are highlighted.

The GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite measures the vertical composition of the atmosphere using the stellar occultation technique. While the night-time data of GOMOS are proved to be of good quality, the daytime observations are more challenging due to poorer signalto-noise ratio. In this paper we present an alternative technique, which uses GOMOS limb scattered radiances instead of the stellar signal, to retrieve stratospheric ozone profiles. Like for many other limb-viewing instruments, GOMOS observations contain stray light at high altitudes. We introduce a method for removing the stray light and demonstrate its feasibility by comparing the corrected radiances against those from the OSIRIS (Optical Spectrograph & Infra Red Imaging System) instrument. For the retrieval of ozone profiles, an onion peeling method is used. The first validation results suggest that the retrieval of stratospheric ozone is possible with a typical accuracy better than 10% at 22-50 km. GOMOS has measured about 350 000 daytime profiles since 2002. The new retrieval method presented here makes this large amount of data finally available for scientific use.

The 4MOST instrument is a multi-object spectrograph that will address Galactic and extragalactic science cases simultaneously by observing targets from a large number of different surveys within each science exposure. This parallel mode of operation and the survey nature of 4MOST require some distinct 4MOST- specific operational features within the overall operations model of ESO. The main feature is that the 4MOST Consortium will deliver, not only the instrument, but also contractual services to the user community, which is why 4MOST is also described as a facility. This white paper concentrates on information particularly useful to answering the forthcoming Call for Letters of Intent.

Fast cadence time resolved spectra taken at the CTIO-4m telescope with the RC-spectrograph during 2 consecutive nights revealed a long term modulation of the binary radial velocity. Chandra hard X-ray spectra taken with the HETGS instrument showed features typically observed in magnetic white dwarfs (WD). Here, we present the new data and suggest that CP Pup is possibly a long orbital period intermediate polar.

Preliminary experiments using a long pulse laser generated X-ray source to backlight a short pulse laser heated thin foil have been performed at the Laboratoire pour l'utilisation des Lasers Intenses (LULI) at Ecole Polytechnique in France. In these experiment, a 2 J, 300 ps, 532 nm laser was used to create the X-ray back-lighter. The primary diagnostic was a von Hamiss spectrograph coupled to a 500 fs X-ray streak camera (TREX-VHS) developed at LLNL-This diagnostic combines high collection efficiency (M lov4 steradims) with fast temporal response (FZ 500 fs), allowing resolution of extremely transient spectral variations. The TFWX-VHS was used to determine the time history, intensity, and spectra3 content of the back-lighter. The second diagnostic, Fourier Domain Interferometry (FDI), provides information about the position of the critical density of the taxget and thus the expansion hydrodynamics, laying the ground work for the plasma characterization. The plasmas were determined to be moderately to strongly coupled, resulting in absorption measurements that provide insight into bound states under such conditions.

NIRSpec (Near Infrared Spectrograph) is one of the four science instruments of the James Webb Space Telescope (JWST) and its focal plane consists of two HAWAII-2RG sensors operating in the wavelength range 0.6 − 5.0µm. As part of characterizing NIRSpec, we studied the noise properties of these detectors under dark and illuminated conditions. Under dark conditions, and as already known, 1/f noise in the detector system produces somewhat more noise than can be accounted for by a simple model that includes white read noise and shot noise on integrated charge. More surprisingly, at high flux, we observe significantly lower total noise levels than expected. We show this effect to be due to pixel-to-pixel correlations introduced by signal dependent inter-pixel crosstalk, with an inter-pixel coupling factor, α, that ranges from ∼ 0.01 for zero signal to ∼ 0.03 close to saturation.

The James Webb Space Telescope, an infrared-optimized space telescope being developed by NASA for launch in 2013, will utilize cutting-edge detector technology in its investigation of fundamental questions in astrophysics. JWST's near infrared spectrograph, NIRSpec utilizes two 2048 x 2048 HdCdTe arrays with Sidecar ASIC readout electronics developed by Teledyne to provide spectral coverage from 0.6 microns to 5 microns. We present recent test and calibration results for the NIRSpec flight arrays as well as data processing routines for noise reduction and cosmic ray rejection.

The Near Infrared Spectrograph (NIRSpec) is one of the four science instruments aboard the James Webb Space Telescope (JWST) scheduled for launch in 2014. NIRSpec is sensitive in the wavelength range from ∼ 0.6 to 5.0 µm and will be capable of obtaining spectra of more than a 100 objects simultaneously, as well as fixed slit high contrast spectroscopy of individual sources. It also features an integral field unit for 3D spectroscopy. The key scientific objectives of the instrument include studies of star formation and chemical abundances of young distant galaxies and tracing the creation of the chemical elements back in time. In this paper, we present the status of the NIRSpec instrument as it is currently being prepared for its extensive ground calibration campaign later in 2010.

Tlie Janies Webb Space Telescope's (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 p i 1 cutoff (A,, = 5 kim) 2048x2048 pixel Teledy~ie HgCdTe HAWAII-2RG sensor chip assemblies. These detect)or arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space a t T-37 K. I11 t,liis article, we provide a brief introductioii to NIRSpec, its detector subsystenl (DS), detector readout in tlie space radintioii eilvironiiiel~t,, and present a snapshot of tlie developineiital status of the NIRSpec DS as iiitegration and test,ing of tlie engi~ieering test unit begins.

The James Webb Space Telescope (JWST) Near Infrared Spectrograph (NIRSpec) incorporates two 5 µm cutoff (λ co = 5 µm) 2048×2048 pixel Teledyne HgCdTe HAWAII-2RG sensor chip assemblies. These detector arrays, and the two Teledyne SIDECAR application specific integrated circuits that control them, are operated in space at T ∼ 37 K. This article focuses on the measured performance of the first flight-candidate, and near-flight candidate, detector arrays. These are the first flight-packaged detector arrays that meet NIRSpec's challenging 6 e − rms total noise requirement.

The Near-Infrared Spectrograph NIRSpec is one of the four instruments of the James Webb Space Telescope (JWST). NIRSpec will cover the 0.6-5.0 micron range and will be capable of obtaining spectra of more than 100 objects simultaneously in its multi-object spectroscopy (MOS) mode. It also features a set of slits and an aperture for high contrast spectroscopy of individual sources, as well as an integral-field unit (IFU) for 3D spectroscopy. We will first show how these capabilities are linked to the four main JWST scientific themes. We will then give an overview of the NIRpec modes and spectral configurations with an emphasis on the layout of the field of view and of the spectra. Last, we will provide an update on the status of the instrument.

We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrograph's (NIRSpec's) detectors will be read out, and present a model of how noise scales with the number of multiple non-destructive reads samplingup-the-ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some non-ideal behaviors that have been observed in engineering grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is: (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.

Background and Objective: MS-2 fibrosarcoma implanted in BALB-CDF1 mice was investigated by frequency and time domain measurements of the autofluorescence (AF) radiation emitted upon excitation by a N 2 laser beam (337.1 nm). Study Design/Materials and Methods: AF spectra were obtained by using a spectrograph, a multichannel plate and an optical multichannel analyzer for the steady state detection. Time-resolved spectra were performed by means of a monochromator, a photomultiplier, and a digital signal analyzer. Results: Spectral measurements show that the autofluorescence intensity of pathologic tissue is lower than that of healthy one in the 400-to 500-spectral region. In the same spectral range, we found the fluorescence decay to be the sum of a fast and a slow component. The lifetime of the fast component of tumoral tissue is significantly lower than that of healthy samples. Conclusion: Frequency and time domain measurements used in combination show that MS2-fibrosarcoma is characterized by the probable presence of the free form of NADH.

Differential Speckle Interferometry (DSI) combines high angular resolution techniques with medium to high resolution spectroscopy. For non resolved sources, it yields the displacement of the object photocenter with wavelength. Combined with the spectrum s (λ), can give information with spatial and/or spectral resolution well beyond the telescope or spectrograph limits. This complementarity is illustrated here with experimental results. For the binary system Capella, we measure the angular separation, separate the spectra of the components and derive the radial velocity difference and the rotation velocity of each component. For the slowly rotating star Aldebaran we obtain the position angle of the stellar rotation axis and a relation between the angular diameter and the rotation velocity which in this case gives the latest.

Context. High resolution observations of the asteroids Iris and Juno have been performed by means of the UV-Visual Echelle Spectrograph (UVES) at the European Southern Observatory (ESO) Very Large Telescope (VLT) to obtain the effective accuracy of the spectrograph's radial velocity. The knowledge of this quantity has important bearings on studies searching for a variability in the fine structure constant carried out with this instrument. Aims. Asteroids provide a precise radial velocity reference at the level of 1 m s −1 , which allows for instrumental calibration and the recognition of small instrumental drifts and calibration systematics. In particular, radial velocity drifts due to nonuniform slit illumination and slit optical misalignment in the two UVES spectrograph arms can be investigated. Methods. We compare the position of the solar spectrum reflected by the asteroids with the solar wavelength positions and with that of asteroid and twilight observations at other epochs to asses the UVES instrumental accuracy. Results. We observe radial velocities offsets in the range of ≈10−50 m s −1 , likely due to a nonuniform slit illumination. However, no radial velocity patterns with wavelengths are detected and the two UVES arms provide consistent radial velocities. These results suggest that the detected ∆α/α variability by Levshakov et al. (2007) deduced from a drift of −180 ± 85 m s −1 at z abs = 1.84, between two sets of Fe ii lines falling in the two UVES arms, may be real or induced by other kinds of systematics than those investigated here. The proposed technique allows us to make a real time quality check of the spectrograph and should be followed for very accurate measurements.

Solar jets are impulsive, collimated plasma ejections that are triggered by magnetic reconnection. They are observed for many decades in various temperatures and wavelengths, therefore their kinematic characteristics, such as velocity and recurrence, have been extensively studied. Nevertheless, the high spatial resolution of the Interface Region Imaging Spectrograph (IRIS) launched in 2013 allowed us to make a step forward in the understanding of the relationship between surges and hot jets. In this paper we report on several results of recent studies of jets observed by IRIS. Cool and hot plasma have been detected with ejections of cool blobs having a speed reaching 300 km s −1 during the impulsive phase of jet formation and slow velocity surges surrounding hot jets after the reconnection phase. Plasma characteristics of solar jets, such as the emission measure, temperature, and density have been quantified. A multi-layer atmosphere at the reconnection site based on observed IRIS spectra has been proposed. IRIS evidenced bidirectional flows at reconnection sites, and tilt along the spectra which were interpreted as the signature of twist in jets. The search of possible sites for reconnection could be achieved by the analysis of magnetic topology. Combining Solar Dynamics Observatory/Helioseismic Magnetic Imager (SDO/HMI) vector magnetograms and IRIS observations, it was found that reconnection site could be located at null points in the corona as well as in bald patch regions low in the photosphere. In one case study a magnetic sketch could explain the initiation of a jet starting in a bald patch transformed to a current sheet in a dynamical way, and the transfer of twist from a flux rope to the jet during the magnetic reconnection process.

The Fiber Optical Cable and Connector System (FOCCoS), provides optical connection between 2400 positioners and a set of spectrographs by an optical fibers cable as part of Subaru PFS instrument. Each positioner retains one fiber entrance attached at a microlens, which is responsible for the F-ratio transformation into a larger one so that difficulties of spectrograph design are eased. The optical fibers cable will be segmented in 3 parts at long of the way, cable A, cable B and cable C, connected by a set of multi-fibers connectors. Cable B will be permanently attached at the Subaru telescope. The first set of multi-fibers connectors will connect the cable A to the cable C from the spectrograph system at the Nasmith platform. The cable A, is an extension of a pseudo-slit device obtained with the linear disposition of the extremities of the optical fibers and fixed by epoxy at a base of composite substrate. The second set of multi-fibers connectors will connect the other extremity of cable A to the cable B, which is part of the positioner's device structure. The optical fiber under study for this project is the Polymicro FBP120170190, which has shown very encouraging results. The kind of test involves FRD measurements caused by stress induced by rotation and twist of the fiber extremity, similar conditions to those produced by positioners of the PFS instrument. The multi-fibers connector under study is produced by USCONEC Company and may connect 32 optical fibers. The tests involve throughput of light and stability after many connections and disconnections. This paper will review the general design of the FOCCoS subsystem, methods used to fabricate the devices involved and the tests results necessary to evaluate the total efficiency of the set.