The Wide Field Spectrograph (WiFeS)

This paper describes the Wide Field Spectrograph (WiFeS) under construction at the Research School of Astronomy and Astrophysics (RSAA) of the Australian National University (ANU) for the ANU 2.3 m telescope at the Siding Spring Observatory. WiFeS is a powerful integral field, double-beam, concentric, image-slicing spectrograph designed to deliver excellent throughput, wavelength stability, spectrophotometric performance and superb image quality along with wide spectral coverage throughout the 320–950 nm wavelength region. It provides a 25×38 arcsec field with 0.5 arcsec sampling along each of twenty five 38×1 arcsec slitlets. The output format is optimized to match the 4096×4096 pixel CCD detectors in each of two cameras individually optimized for the blue and the red ends of the spectrum, respectively. A process of “interleaved nod-and-shuffle” will be applied to permit quantum noise-limited sky subtraction. Using VPH gratings, spectral resolutions of 3000 and 7000 are provided. The full spectral range is covered in a single exposure at R=3000, and in two exposures in the R=7000 mode. The use of transmissive coated optics, VPH gratings and optimized mirror coatings ensures a throughput (including telescope atmosphere and detector) >30% over a wide spectral range. The concentric image-slicer design ensures an excellent and uniform image quality across the full field. To maximize scientific return, the whole instrument is configured for remote observing, pipeline data reduction, and the accumulation of calibration image libraries.     

IFU Unit in Scorpio-2 Focal Reducer for Integral-Field Spectroscopy on the 6-m Telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences

We describe the scheme and design features of the new IFU unit (Integral Field Unit) meant to perform integral-field spectroscopy as a part of SCORPIO-2 focal reducer, which is mounted in the prime focus of the 6-m telescope of the Special Astrophyscial Observatory of the Russian Academy of Sciences. The design of the unit is based on the principle of the formation of array spectra using a lens raster combined with optical fibers. The unit uses a rectangular raster consisting of 22×22 square 2-mm diameter lenses. The image of the object is transferred by an optical system with a 23^× magnification from the focal plane of the telescope to the plane of the lens raster. The image scale is —0.″75/lens and the field of view of the instrument has the size of 16.″5 × 16.—5². The raster also contains two extra 2 × 7 lens arrays to acquire the night-sky spectra whose images are offset by ±3′from the center. Optical fibers are used to transform micropupil images into two pseudoslits located at the IFU collimator entrance. When operating in the IFU mode a set of volume phase holographic gratings (VPHG) provides a spectral range of 4600–7300 Å and a resolution λ/δλ of 1040 to 2800. The quantum efficiency of SCORPIO-2 field spectroscopy is 6–13% depending on the grating employed.We describe the technique of data acquisition and reduction using IFU unit and report the results of test observations of the Seyfert galaxyMrk 78 performed on the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences.     

基于OMR的2．16米望远镜积分视场单元方案

基于积分视场单元的三维成像光谱技术日趋成熟,并且与传统的狭缝光谱仪相比有许多明显的优势。2．16m望远镜的OMR光谱仪是采用平面光栅分光的低色散卡焦光谱仪器,可以考虑对其进行积分视场单元的升级优化。在不改变OMR光谱仪自身结构,不影响现有功能的同时,利用“微透镜阵列＋光纤束”的技术可以实现积分视场单元与OMR光谱仪的耦合。设计了两种方案,给出了升级积分视场单元后的空间分辨率和视场。     

30m级光学/红外望远镜的宽视场多目标光谱仪

宽视场多目标光谱仪具有宽波段、多分辨率模式和高通光效率的特点,是极大望远镜终端仪器使用率最高的通用型仪器. 30 m级望远镜的宽视场多目标光谱仪因体量和成本急剧增加而面临重要挑战,同时天文学的不断发展对天文新技术的发展提出了更高的要求,尤其是多个巡天项目对于多目标光谱后随观测的迫切需求.综述了几类宽视场多目标光谱仪的发展现状,介绍了国际3架30 m望远镜宽视场多目标光谱仪概念设计的最新进展和仪器特点,着重介绍了中国参与研制的30 m望远镜(TMT)中的宽视场多目标光谱仪的相关进展.     

Extragalactic integral field spectroscopy on the Gemini telescopes

We have been undertaking a programme on the Gemini 8‐m telescopes to demonstrate the power of integral field spectroscopy, using the optical GMOS spectrograph, and the new CIRPASS instrument in the near‐infrared. Here we present some preliminary results from 3D spectroscopy of extra‐galactic objects, mapping the emission lines in a 3CR radio galaxy and in a gravitationally lensed arc, exploring dark matter sub‐structure through observations of an Einstein Cross gravitational lens, and the star formation time‐scales of young massive clusters in the starburst galaxy NGC 1140. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Observing GRB host galaxies with the integral field unit of X‐shooter

Using the integral field unit of X‐shooter at VLT, we have recovered the first velocity fields of GRB host galaxies at redshift <0.6. This facility is able to recover not only the velocity fields from almost all emission lines thanks to an unrivaled wavelength coverage, but also to recover maps of physical properties. We present the preliminary analysis of X‐shooter/IFU observations dedicated to the study of GRB host galaxies undertaken in the frame of the Italian‐French GTO program. Our goal is to understand the physical processes at the origin of the GRB by analyzing in detail the spatial distributions of the kinematics, metallicities, extinction, star‐formation, and how they are inter‐related (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The GraF instrument for Imaging Spectroscopy with the Adaptive Optics

The GraF instrument using a Fabry-Perot interferometer cross-dispersed with a grating was one of the first integral-field and long-slit spectrographs built for and used with an adaptive optics system. We describe its concept, design, optimal observational procedures and the measured performances. The instrument was used in 1997–2001 at the ESO3.6 m telescope equipped with ADONIS adaptive optics and SHARPII+camera. The operating spectral range was 1.2–2.5 μm. We used the spectral resolution from 500 to 10 000 combined with the angular resolution of 0.1″–0.2″. The quality of GraF data is illustrated by the integral field spectroscopy of the complex0.9″ × 0.9″ central region of η Car in the1.7 μm spectral range at the limit of spectral and angular resolutions. This revised version was published online in July 2006 with corrections to the Cover Date.     

Gemini GMOS/integral field unit spectroscopy of NGC 1569 – II. Mapping the roots of the galactic outflow

We present a set of four Gemini-North Multi-Object Spectrograph/integral field unit (IFU) observations of the central disturbed regions of the dwarf irregular starburst galaxy NGC 1569, surrounding the well-known superstar clusters A and B. This continues on directly from a companion paper, in which we describe the data reduction and analysis techniques employed and present the analysis of one of the IFU pointings. By decomposing the emission-line profiles across the IFU fields, we map out the properties of each individual component identified and identify a number of relationships and correlations that allow us to investigate in detail the state of the ionized interstellar medium (ISM). Our observations support and expand on the main findings from the analysis of the first IFU position, where we conclude that a broad (≲400 km s⁻¹) component underlying the bright nebular emission lines is produced in a turbulent mixing layer on the surface of cool gas knots, set up by the impact of the fast-flowing cluster winds. We discuss the kinematic, electron-density and excitation maps of each region in detail and compare our results to previous studies. Our analysis reveals a very complex environment with many overlapping and superimposed components, including dissolving gas knots, rapidly expanding shocked shells and embedded ionizing sources, but no evidence for organized bulk motions. We conclude that the four IFU positions presented here lie well within the starburst region where energy is injected, and, from the lack of substantial ordered gas flows, within the quasi-hydrostatic zone of the wind interior to the sonic point. The net outflow occurs at radii beyond 100–200 pc, but our data imply that mass-loading of the hot ISM is active even at the roots of the wind.     

3D spectroscopy of z ∼ 1galaxies with gemini

Area spectroscopy has significant advantages over both traditional imaging and long-slit spectroscopy: it is more efficient in observing time, and yields substantially more information. Through Integral Field Units, area spectroscopy is becoming an essential part of new facility instruments on the latest large telescopes. We have been undertaking a programme on the Gemini 8-m telescopes to demonstrate the power of integral field spectroscopy, using the optical GMOS spectrograph, and the new CIRPASS instrument in the near-infrared. Here we present some preliminary results from 3D spectroscopy of z ∼ 1 objects, mapping the emission lines in a 3CR radio galaxy and in a gravitationally lensed arc. This revised version was published online in August 2006 with corrections to the Cover Date.     

A detailed view on the kinematics of candidate intermediate luminosity early‐type galaxies with a lack of dark matter

In several nearby L ∼ L_* early‐type galaxies, recent observations at large radii have shown indications of a lack of dark matter, substantially at odds with the prediction from the Cold Dark Matter (CDM) hierarchical merger models. Here we discuss a pilot observational project for the study of the internal kinematical and dynamical properties of this remarkable sample of galaxies. Using the VIMOS‐IFU in its high spectral resolution mode, it would be possible to investigate the regions up to ∼1.2 R_e, taking advantage of the much larger field of view and telescope diameter. This will allow to disclose the presence of any kinematical substructures which could affect the conclusion on the mass modeling and definitely clarify the inner structure of this particular class of early‐type galaxies. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

NLST: India's National Large Solar Telescope

This article introduces the new Indian 2 m telescope which has been designed by MT Mechatronics in a detailed conceptual design study for the Indian Institute of Astrophysics, Bangalore. We describe the background of the project and the science goals which shall be addressed with this telescope. NLST is a solar telescope with high optical throughput and will be equipped with an integrated Adaptive Optics system. It is optimized for a site with the kind of seeing and wind conditions as they are expected at a lake site in the Himalayan mountains. The telescope can also be used for certain night time applications. We also give the scientific rationale for this class of telescope (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The origin of [Fe ii] emission in NGC 4151

The centre of NGC 4151 has been observed in the J band with the SMIRFS integral field unit (IFU) on the UK Infrared Telescope. A map of [Fe  ii ] emission is derived, and compared with the distributions of the optical narrow-line region and radio jet. We conclude that, because the [Fe  ii ] emission is associated more closely with the visible narrow-line region than with the radio jet, it arises mainly through photoionization of gas by collimated X-rays from the Seyfert nucleus. The velocity field and strength with respect to Pa β are found to be consistent with this argument. The performance of the IFU is considered briefly, and techniques for observation and data analysis are discussed.     

TRAFICOS – an Échelle Zeeman spectrograph

We describe the TRAnsportable Flbre COupled échelle Spectrograph (TRAFICOS) equipped with a Zeeman analyzer and manufactured mainly for the observation of stellar magnetic fields. The spectrograph, designed at the Astrophysikalisches Institut Potsdam and constructed at the Thüringer Landessternwarte Tautenburg, is laid out in a quasi-Littrow configuration. The part attached to the Nasmyth focus of the 2 m telescope contains the telescope adapter for the fibre input and output of the star and calibration light, the cases for the flatfield and the wavelength calibration, and the Zeeman analyzer. The optical scheme and the reduction software are mentioned in some details and the first results of the determination of the magnetic field and radial velocity of several stars are given showing the performance of the device in comparison with existing data.     

Techniques for reducing fiber‐fed and integral‐field spectroscopy data: An implementation on R3D

This paper describes the general characteristics of raw data from fiber‐fed spectrographs in general and fiber‐fed IFUs in particular. The different steps of the data reduction are presented, and the techniques used to address the unusual characteristics of these data are described in detail. These techniques have been implemented in a specialized software package, R3D, developed to reduce fiber‐based integral field spectroscopy (IFS) data. The package comprises a set of command‐line routines adapted for each of these steps, suitable for creating pipelines. The routines have been tested against simulations, and against real data from various integral field spectrographs (PMAS, PPAK, GMOS, VIMOS and INTEGRAL). Particular attention is paid to the treatment of cross‐talk. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Wide Field Multi-object Spectrograph for 30 m Class Optical/Near-infrared Telescopes

Due to its wide wavelength coverage, multi-resolution mode, and high transmission efficiency, the wide field multi-object spectrograph becomes the most common-used universal instrument in extremely large telescopes. It's still a great challenge to build the wide field multi-object spectrograph for a 30 m class telescope because of its sharply increased volume and budget. With the rapid development of astronomy and astrophysics, the innovation of astronomical technology is fundamentally required. In this paper, the research progress of different kinds of wide-field multi-object spectrographs is illustrated and reviewed, the recent status of conceptual designs and the instrument features of the wide field multi-object spectrographs of the three 30 m class telescopes in the world, especially the current effort made by the Chinese team for the wide field multi-object spectrograph of the Thirty Meter Telescope (TMT) are introduced.     

Integral field spectroscopy of the gravitational lens HE1104‐1805

We present integral field spectroscopy of the double imaged quasar HE1104‐1805 taken with the optical fiber system INTEGRAL‐WYFFOS at theWHT telescope. From the spectra of the two components we have measured the continuum and line emission ratios, finding an offset between them that can be related to microlensing. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

FIRST RESULTS OF THE SUMER TELESCOPE AND SPECTROMETER ON SOHO – II. Imagery and Data Management

SUMER – Solar Ultraviolet Measurements of Emitted Radiation – is not only an extreme ultraviolet (EUV) spectrometer capable of obtaining detailed spectra in the range from 500 to 1610 Å, but, using the telescope mechanisms, it also provides monochromatic images over the full solar disk and beyond, into the corona, with high spatial resolution. We report on some aspects of the observation programmes that have already led us to a new view of many aspects of the Sun, including quiet Sun, chromospheric and transition region network, coronal hole, polar plume, prominence and active region studies. After an introduction, where we compare the SUMER imaging capabilities to previous experiments in our wavelength range, we describe the results of tests performed in order to characterize and optimize the telescope under operational conditions. We find the spatial resolution to be 1.2 arc sec across the slit and 2 arc sec (2 detector pixels) along the slit. Resolution and sensitivity are adequate to provide details on the structure, physical properties, and evolution of several solar features which we then present. Finally some information is given on the data availability and the data management system.     

E3D,the Euro3D visualization tool II: Mosaics,VIMOS data and large IFUs of the future

In this paper, we describe the capabilities of E3D, the Euro3D visualization tool, to handle and display data created by large Integral Field Units (IFUs) and by mosaics consisting of multiple pointings. The reliability of the software has been tested with real data, originating from the PMAS instrument in mosaic mode and from the VIMOS instrument, which features the largest IFU currently available. The capabilities and limitations of the current software are examined in view of future large IFUs, which will produce extremely large datasets. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)