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MEGASTAR is a stellar spectral atlas for MEGARA (Multi Espectrógrafo en GTC de Alta Resolución para Astronomía). MEGARA is an optical (3650 – 9750 Å), fiber-fed, medium-high spectral resolution (R = 6000, 12000, 20000) instrument in operation on the GTC 10.4m telescope. The scientific exploitation of MEGARA demanded a stellar-spectra library to interpret galaxy data and to estimate the contribution of the stellar populations. MEGASTAR atlas is focused on the highest resolution setups, HR-R and HR-I, and already has almost 1000 stars (twice spectra) thanks to the filler-type OpenTime obtained up to now in 7 semesters. We have developed a web-based tool and a database that allow working in the project (for MEGASTAR team) and making the observations and products available to the scientific community.

We present the main results from the analysis of the Hα-[NII] emission lines with integral field spectroscopy observations gathered with MEGARA at the GTC of the nearby Seyfert 1.5 galaxy NGC7469. We obtained maps of the ionised gas in the inner 12.5 arcsec × 11.3 arcsec, at spatial scales of 0.62 arcsec, with an unprecedented spectral resolution (R ˜ 20 000). We characterized the kinematics and ionisation mechanism of the distinct kinematic components (Cazzoli et al.2019).

SCORPIO is the next facility instrument for the Gemini South telescope at Cerro Pachon, Chile. SCORPIO’s main science driver is the detection and monitoring of faint time-domain events, in particular the follow-up of discoveries by the Vera C. Rubin Observatory, but it can also carry out with unique efficiency a large variety of astrophysical programs. The instrument has recently passed Critical Design Review and is now in its Assembly, Integration and Verification phase. In this paper we provide an updated overview of the final instrument design and the main performance parameters in light of the science drivers.

We present a comprehensive analysis of the multiphase structure of the interstellar medium (ISM) and the stellar kinematics in the edge-on nearby galaxy UGC 10205 using integral field spectroscopy (IFS) data taken with Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA) at the GTC. We explore both the neutral and the ionized gas phases using the interstellar Na i D doublet absorption (LR-V setup, R ∼ 6000) and the Hα emission line (HR-R setup, R ∼ 18000), respectively. The high-resolution data show the complexity of the Hα emission-line profile revealing the detection of up to three kinematically distinct gaseous components. Despite of this fact, a thin-disk model is able to reproduce the bulk of the ionized gas motions in the central regions of UGC 10205. The use of asymmetric drift corrections is needed to reconciliate the ionized and the stellar velocity rotation curves. We also report the detection of outflowing neutral gas material blueshifted by ∼ 87 km s-1. The main physical properties that describe the observed outflow are a total mass M out = (4.55 0.06) 107 M and a cold-gas mass outflow rate M yr-1. This work points out the necessity of exploiting high-resolution IFS data to understand the multiphase components of the ISM and the multiple kinematical components in the central regions of nearby galaxies. © 2020. The American Astronomical Society. All rights reserved.., The authors acknowledge financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under grant No. AYA2016-75808-R, which is partly funded by the European Regional Development Fund (ERDF), AYA2017-90589-REDT, RTI2018-096188-B-I00, S2018/NMT-4291, and ESP2017-83197P projects. C.C.T. gratefully acknowledges the support of the European Youth Employment Initiative (YEI) by means of the Postdoctoral Fellowship Program. G.B. acknowledges financial support from DGAPA-UNAM through PAPIIT project IG100319.

Disky bulges in spiral galaxies are commonly thought to form out of disk materials (mainly) via bar-driven secular processes. They are structurally and dynamically distinct from >classical bulges,> which are built in violent merger events. We use high-resolution GTC/MEGARA integral-field unit spectroscopic observations of the Sa galaxy NGC 7025, obtained during the MEGARA commissioning run, together with detailed 1D and 2D decompositions of this galaxy's Sloan Digital Sky Survey i-band data to investigate the formation of its disky (bulge) component, which makes up ∼30% of the total galaxy light. With a Sérsic index n ∼ 1.80 ± 0.24, a half-light radius Re ∼ 1.70 ± 0.43 kpc, and stellar mass M ∗ ∼(4.34 ± 1.70) × 10 10 M o , this bulge dominates the galaxy light distribution in the inner (∼4.7 kpc). Measuring the spins (λ) and ellipticities (ϵ) enclosed within nine different circular apertures with radii R ≤ Re, we show that the bulge, which exhibits a spin track of outwardly rising λ and , is a fast rotator for all the apertures considered. Our findings suggest that this inner disky component is a pseudo-bulge, consistent with the stellar and dust spiral patterns seen in the galaxy down to the innermost regions but in contrast to the classical bulge interpretation favored in the past. We propose that a secular process involving the tightly wound stellar spiral arms of NGC 7025 may be driving gas and stars out of the disk into the inner regions of the galaxy, building up the massive pseudo-bulge. © 2019. The American Astronomical Society. All rights reserved., We thank the referee for their careful reading of the paper and many suggestions that improved the paper. B.T.D. acknowledges support from a Spanish postdoctoral fellowship, >Ayudas 1265 para la atraccion del talento investigador. Modalidad 2: jovenes investigadores,> funded by Comunidad de Madrid under grant no. 2016-T2/TIC-2039. We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness under grant no. AYA2016-75808-R, which is partly funded by the European Regional Development Fund, and from the Excellence Network MaegNet (AYA2017-90589-REDT). We acknowledge financial support from SpaceTec-CM: Desarrollo de nuevas tecnologias para instrumentacion espacial en la Comunidad de Madrid, S2013/ICE-2822. Funding for SDSS-IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah.

Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors – something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future.

SUMO is an Operation and Maintenance Management web tool, which allows managing the operation and maintenance activities and resources required for the exploitation of a complex facility. SUMO main capabilities are: information repository, assets and stock control, tasks scheduler, executed tasks archive, configuration and anomalies control and notification and users management. The information needed to operate and maintain the system must be initially stored at the tool database. SUMO shall automatically schedule the periodical tasks and facilitates the searching and programming of the non-periodical tasks. Tasks planning can be visualized in different formats and dynamically edited to be adjusted to the available resources, anomalies, dates and other constrains that can arise during daily operation. SUMO shall provide warnings to the users notifying potential conflicts related to the required personal availability or the spare stock for the scheduled tasks. To conclude, SUMO has been designed as a tool to help during the operation management of a scientific facility, and in particular an astronomical observatory. This is done by controlling all operating parameters: personal, assets, spare and supply stocks, tasks and time constrains.

MEGARA (Multi Espectrografo en GTC de Alta Resolucion para Astronomia) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the 10.4-m Gran Telescopio CANARIAS (GTC). MEGARA has three different fiber bundles, the Large Central Bundle covering 12.5 arcsec x 11.3 arcsec on sky, the Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec, and a Fiber MOS positioner system that is able to place up to 100 mini-bundles with 7 fibers each in MOS configuration within a 3.5 arcmin x 3.5 arcmin FOV. The MEGARA focal plane subsystems are located at one of the GTC Folded Cassegrain focal stations. A field lens provides a telecentric focal plane, where the fibers are located. Micro-lenses arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers. Finally, the fibers, organized in bundles conducted the light from the focal plane to the pseudo-slit plates at the entrance of the MEGARA spectrograph, which shall be located at one of the Nasmyth platforms. This article also summarizes the prototypes already done and describes the set-up that shall be used to integrate fibers and micro-lens and characterize the fiber bundles.

We have studied the physical conditions in the central 300 pc of the proto-typical starburst galaxy NGC 7714. Our analysis is based on ultraviolet spectroscopy with the HST+GHRS and ground-based optical observations.The data are interpreted using evolutionary models optimized for young starburst regions. The massive stellar population is derived in a self-consistent way using the continuum and stellar absorption lines in the ultraviolet and the nebular emission line optical spectrum. The central starburst has an age of about 4.5 Myr, with little evidence for an age spread. Wolf-Rayet features at the ultraviolet indicates a stellar population of $\sim$ 2000 Wolf-Rayet stars. The overall properties of the newly formed stars are quite similar to those derived, e.g., in 30 Doradus. A standard Salpeter IMF is consistent with all observational constraints. We find evidence for spatial structure within the central 300 pc sampled. Therefore it is unlikely that the nucleus of NGC 7714 hosts a single star cluster exceeding the properties of other known clusters. Contrary to previous suggestions, we find no evidence for a nuclear supernova rate that would significantly exceed the total disk-integrated rate. About one supernova event per century is predicted., 19 pages, 9 figures in a tar file. Accepted for publication in ApJ, 1999, March, issue 513

MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is a facility instrument of the 10.4m GTC (La Palma, Spain) working at optical wavelengths that provides both Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) capabilities at resolutions in the range R= 6,000-20,000. The MEGARA focal plane subsystems are located at one of the GTC focal stations, while the MEGARA refractive VPH based spectrograph is located at one of the Nasmyth platforms. The fiber bundles conduct the light from the focal plane subsystems to the pseudo-slits at the entrance of the spectrograph. The project is an initiative led by Universidad Complutense de Madrid (Spain) in collaboration with INAOE (Mexico), IAA-CSIC (Spain) and Universidad Politecnica de Madrid (Spain) and is developed under contract with GRANTECAN. The project is carried out by a multidisciplinary and geographically distributed team, which includes the in-kind contributions of the project partners and personnel from several private companies. The MEGARA system-engineering plan has been tailored to the project and is being applied to ensure the technical control of the project in order to finally meet the science high-level requirements and GTC constrains.

The project management of complex instruments for ground-based large telescopes is a challenge itself. A good management is a clue for project success in terms of performance, schedule and budget. Being on time has become a strict requirement for two reasons: to assure the arrival at the telescope due to the pressure on demanding new instrumentation for this first world-class telescopes and to not fall in over-costs. The budget and cash-flow is not always the expected one and has to be properly handled from different administrative departments at the funding centers worldwide distributed. The complexity of the organizations, the technological and scientific return to the Consortium partners and the participation in the project of all kind of professional centers working in astronomical instrumentation: universities, research centers, small and large private companies, workshops and providers, etc. make the project management strategy, and the tools and procedures tuned to the project needs, crucial for success. MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is a facility instrument of the 10.4m GTC (La Palma, Spain) working at optical wavelengths that provides both Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) capabilities at resolutions in the range R=6,000-20,000. The project is an initiative led by Universidad Complutense de Madrid (Spain) in collaboration with INAOE (Mexico), IAA-CSIC (Spain) and Universidad Politecnica de Madrid (Spain). MEGARA is being developed under contract with GRANTECAN.

High-resolution Hubble Space Telescope ultraviolet images of the Seyfert 2 galaxies NGC 1667, NGC 3982, NGC 5427, and NGC 5953, previously known to have circumnuclear star-forming rings, are presented. The UV images of all four Seyfert 2 galaxies show the presence of several compact UV-bright knots at distances of ~0.7-2 kpc from the nucleus and associated to the circumnuclear star-forming ring. The optically bright Seyfert 2 nucleus is barely detected in the UV. The UV images provide the first direct empirical evidence that the UV flux emitted by galaxies having a Seyfert 2-type nucleus surrounded by a circumnuclear star-forming ring is dominated by radiation coming from clusters of young hot stars distributed along the star-forming ring. The contribution of the Seyfert 2 nucleus amounts to ~1%-10% of the observed UV flux in these four galaxies. If circumnuclear star-forming rings of 2-3 kpc in diameter, or smaller, are a common feature of Seyfert 2 galaxies, we conclude that (a) the observed UV flux in Seyfert 2 galaxies is not dominated by the radiation from the nuclear ionizing source and (b) the observed UV flux is dominated by emission from clusters of young hot stars located in circumnuclear star-forming regions. Whatever the nature of the nuclear ionizing source in these Seyfert 2 galaxies, this must be obscured. The UV and Hα luminosities associated to the Seyfert 2 nucleus in these galaxies are consistent with the scenario of the nuclear ionizing source being an obscured power-law ionizing source or a young (2-4 Myr) obscured high-metallicity (≥Z☉) nuclear starburst.

A high-resolution Hubble Space Telescope WFPC2 F218W UV image of the barred spiral NGC 4303 (classified as a LINER-type active galactic nucleus [AGN]) reveals for the first time the existence of a nuclear spiral structure of massive star-forming regions all the way down to the UV-bright unresolved core (size ≤ 8 pc) of an active galaxy. The spiral structure, as traced by the UV-bright star-forming regions, has an outer radius of 225 pc and widens as the distance from the core increases. The UV luminosity of NGC 4303 is dominated by the massive star-forming regions, and the unresolved LINER-type core contributes only 16% of the integrated UV luminosity. The nature of the UV-bright LINER-type core—stellar cluster or pure AGN—is still unknown. In contrast to NGC 4303, the UV F218W image of the non-AGN barred galaxy NGC 3351 shows a nuclear star-forming ring of 315 pc (semimajor axis) with a faint core. In the ring, the star formation is arranged in clumps of about 60-85 pc in diameter. Each clump consists of a few compact UV-bright clusters embedded in a more diffuse component. The integrated IUE spectrum of NGC 3351 shows the presence of Si IV 1400 A and C IV 1550 A absorption lines, typical features of young, 4-5 Myr old, massive star clusters. The presence of ring and spiral star-forming structures in the nuclear regions of these two barred spirals supports the bar-induced gas-fueling scenario by which bars accumulate gas in the nuclear regions of galaxies, produce nuclear star-forming rings (NGC 3351), and might eventually generate or feed an AGN (NGC 4303).

In this work we investigate the stellar content of three circumnuclear giant H II regions in the starburst galaxy NGC 7714. We model the stellar population that best reproduces the observational constraints given by the Hα image and the optical spectroscopy from 3710 to 9700 A. In this paper we address a robust method for analyzing the stellar content of giant extragalactic H II regions (GEHRs) as a first step in a strategy that should allow us to understand better how star formation proceeds. To test the power of the method, we have chosen three very well-studied regions in which many observational constraints are known. The models reproduce simultaneously the observed sizes derived from the Hα image, the emission-line spectrum from the gaseous component, and the optical features from the massive stars such as Wolf-Rayet bumps in emission, and the near-infrared calcium triplet, CaT, in absorption when detected. We fit the stellar populations through evolutionary synthesis models plus the photoionization code CLOUDY, under the assumption of a shell geometry for the regions. This approach allows us to derive the physical properties of the star clusters, such as mass, age, and metallicity, inside these GEHRs. The method is based on previous work of a complete grid of photoionization models for giant H II regions ionized by evolving star clusters of different metallicities (from 0.05 to 2.5 times solar) and ages between 1 and 5.4 Myr. For the present work, we have followed the cluster evolution further, even after the ionization phase has come to an end, in order to reproduce the observed values of the continuum luminosity at 9000 A and the equivalent widths of Hβ in emission and CaT in absorption. From the results, we find in two of the three studied regions that a single ionizing stellar burst is sufficient to explain all the observational constraints if no reddening is affecting the cluster continuum. Otherwise, the observed values of the Hβ equivalent widths imply the existence of an older component. In this latter case, we find that a model in which two bursts of star formation are considered, a young ionizing one, with ages 3-5 Myr and an older one of 7-9 Myr, that can reproduce the observations. In the third region, the presence of CaT in the near-IR indicates the presence of a non-ionizing population, whose origin is thoroughly discussed.

This is the third paper of a series reporting the results from the POPSTAR evolutionary synthesis models. The main goal of this work is to present and discuss the synthetic photometric properties of Single Stellar Populations (SSPs) resulting from our POPSTAR code. Colours in the Johnson and SDSS systems, halpha and hbeta luminosities and equivalent widths, and ionising region size, have been computed for a wide range of metallicity (Z = 0.0001 - 0.05) and age (0.1 Myr to 20 Gyr). We demonstrate the importance of the contribution of emission lines to broader-band photometry when characterising stellar populations, through the presentation of both contaminated and non-contaminated colours (in both the Johnson and SDSS systems). The tabulated colours include stellar and nebular components, in addition to line emission. The main application of these models is the determination of physical properties of a given young ionising cluster, when only photometric observations are available; for an isolated star forming region, the young star cluster models can be used, free from the contamination of any underlying background stellar population. In most cases, however, the ionising population is usually embedded in a large and complex system, and the observed photometric properties result from the combination of a young star-forming burst and the underlying older population of the host. Therefore, the second objective of this paper is to provide a grid of models useful in the interpretation of mixed regions where the separation of young and old populations is not sufficiently reliable. We describe the set of PopStar Spectral Energy Distributions, the derived colours and other photometric parameters, for mixed populations where an underlying host population is combined in different mass ratios with a recent ionising burst., 28 pages, 23 figures, accepted for MNRAS

We describe the optical design of MEGARA, the future optical Integral Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the 10.4-m Gran Telescopio CANARIAS (GTC). MEGARA is being built by a Consortium of public research institutions led by the Universidad Complutense de Madrid (UCM, Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain).

This paper describes MANATEE, which is the Management project web tool developed by FRACTAL, specifically designed for managing large astronomical projects. MANATEE facilitates the management by providing an overall view of the project and the capabilities to control the three main projects parameters: scope, schedule and budget. MANATEE is one of the three tools of the FRACTAL System & Project Suite, which is composed also by GECO (System Engineering Tool) and DOCMA (Documentation Management Tool). These tools are especially suited for those Consortia and teams collaborating in a multi-discipline, complex project in a geographically distributed environment. Our Management view has been applied successfully in several projects and currently is being used for Managing MEGARA, the next instrument for the GTC 10m telescope.

MEGARA (Multi-Espectrografo en GTC de Alta Resolucion para Astronomia) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the GTC 10.4m telescope. This contribution summarizes the current mechanical design of the spectrograph and the adopted solutions for the mechanisms and the opto-mechanical components.

MEGARA is a multi-object spectrograph project for the 10.4m Gran Telescopio Canarias with medium to high resolution: R ~ 5600 - 17000. The instrument operates in three modes that cover different sky areas and that can run simultaneously: (1) the compact mode through a large central Integral Field Unit with minimum fiber pitch, covering a field of view on sky of 12 arcsec × 14 arcsec, (2) the sparse mode with fibers covering 1 arcmin × 1arcmin in three pointings and (3) the dispersed mode with a grid of nearly 100 robotics positioners able to place 7-fiber minibundles over a large field of view of 3.5 arcmin × 3.5 arcmin. The spectrograph is composed by a pseudo-slit, where the fibers are placed simulating a long slit; a slit shutter is placed just behind the pseudo-slit, a collimator, a 162mm pupil where the volume phase holographic gratings are placed, and the camera with the detector. Here we describe the spectrograph optical rationale, the conceptual optical design and the expected system performance.

We report IUE observations of two extremely low-metallicity H II galaxies. Ly α emission was detected in both galaxies. Our results confirm previous findings that young or unevolved galaxies exhibit weak or absent Lyα emission combined with a strong UV continuum, and that the Lyα/Hβ ratio and metal content are correlated in the sense that the lower the abundance, the larger the ratio. This supports the hypothesis that in the higher metallicity systems Lyα is destroyed by dust absorption.

In the frame of the Starburst Model, we show that the evolution of a massive stellar cluster in a high metallicity environment can reproduce the observed emission-line spectrum and the UV-optical Spectral Energy Distribution of the Seyfert 2 galaxies and LINERs. We apply the results of our models to three objects: NGC 5506, NGC 5643 and Mk 348.

This paper describes the FRACTAL Systems & Projects suite. This suite is composed by several tools (GECO, DOCMA and SUMO) that provide the capabilities that all organizations need to store and manage the system information generated along the project's lifetime, from the design phase to the operation phase. The amount of information that is generated in a project keeps growing in size and complexity along the project's lifetime, to an extent that it becomes impossible to manage it without the aid of specific computer-based tools. The suite described in this paper is the solution developed by FRACTAL to assist the execution of different scientific projects, mainly related with telescopes and instruments, for astronomical research centres. These tools help the system and project engineers to maintain the technical control of the systems and to ensure an optimal use of the resources. GECO eases the control of the system configuration data; DOCMA provides the means to organise and manage the documents generated in the project; SUMO allows managing and scheduling the operation, the maintenance activities and the resources during the operational phase of a system. These tools improve the project communication making the information available to the authorized users (project team, customers, Consortium's members, etc). Finally and depending on the project needs, these three tools can be used integrated or in an independent manner.

The Gran Telescopio Canarias (GTC) 10.4m telescope will be having its first light soon after this meeting. A fairly complete set of science instruments are being prepared for installation at the GTC soon after first light or a couple of year after in the case of the second generation instruments. In this talk I will describe the main features of the various instruments and discuss their completion status. In particular I will dwell on the Tuneable filters combined with a wide field and charge shuffling capabilities of OSIRIS, Elmer's outstanding throughput, and the thermal IR polarimetry and coronagraphy capabilities of CanariCam. I will also show the wide field multi-object K band spectroscopic capabilities of EMIR, the first of the second-generation instruments. Finally, I will describe CIRCE, a near IR camera being offered by the UF for GTC, and FRIDA, a near IR AO geared imager and IFU spectrograph meant to exploit the GTC AO system.

The Gran Telescopio Canarias (GTC1) 10m telescope is now being integrated at the ORM, in La Palma Spain. Likewise, three instruments are being prepared for first light and, as of this writing, are about to start their laboratory integration. These first light instruments are: 1) OSIRIS, a large field of view imager and multi-object spectrograph, optimized for tuneable filter imaging, 2) ELMER a very sensitive imager and spectrograph, also for the visible range, and 3) CANARICAM, a diffraction-limited imager, spectrograph, polarimeter and coronagrapher for the mid-IR. The GTC set of first light instruments will offer some special observational capabilities to the astronomical community, namely Tuneable filter Imaging in OSIRIS, fast spectroscopy and photometry in both, ELMER and OSIRIS, and 10 microns Coronagraphy and Polarimetry with CANARICAM. Yet another instrument, EMIR, a large field, near-IR multi-object spectrograph and imager is in the Detailed Design phase. EMIR will be the first of the GTC second generation set of instruments. At the planning stage are several future instruments that will arrive to the GTC with different calendars after Day One. In particular, FRIDA, a near-IR diffraction-limited imager and spectrograph, that will operate with the GTC Adaptive Optics system. FRIDA's conceptual design is being started by a consortium lead by UNAM (Mexico) and in which the IAC and the University of Florida also participate. FRIDA should be at the telescope by the time that the AO system is having first light. This is expected by late 2007 early 2008. There is interest in the GTC community for installing visiting instruments on the GTC, thus the GTC board is discussing a policy to allow visitor instruments, some of which have already been proposed to be hosted by the GTC. In particular, CIRCE is a near IR camera that is being built by the Department of Astronomy of the University of Florida in Gainesville for the GTC using private funds, under the GTC visitor instrument scheme. CIRCE should bridge the gap between Day One and the arrival of EMIR enabling near IR imaging capabilities to the GTC.

ELMER is a visible imager and spectrograph for the GTC. ELMER is currently in the final stage of testing (at the PO in La Laguna, Tenerife) previous to be shipped to the Observatorio del Roque de los Muchachos in the island of La Palma, where the GTC telescope is being integrated. ELMER Optics has been exhaustively tested at different steps, from the blanks to the final assemblies in order to guarantee the required performance. In this contribution, we will describe the tests done to the different optical components until now. Blank testing, WFE Image quality and transmission tests have been carried out for most of the components. A brief review of some of these tests is included in the following sections as well as a list of references where the test assemblies and the results are discussed in detail.

ELMER is an instrument for the GTC designed to observe between 365 and 1000 nm. The observing modes for the instrument at Day One shall be: Imaging, Long Slit and Mask-Multi-object Spectroscopy, Slit-less multi-object spectroscopy, Fast Photometry and Fast short-slit spectroscopy, over a FOV of 4.2 arcmin diameter. Spectral resolutions of 250, 1000 and 2500, covering the whole spectral range, will be available. ELMER has been designed and managed within the GTC Project Office. ELMER is currently in the final stage of testing previous to be shipped to the Observatory. The general description of this instrument and its expected scientific performance are summarised.

ELMER is an optical instrument for the GTC designed to observe between 3650 and 10000 Armstrong. The observing modes for the instrument at Day One shall be: Imaging, Long Slit Spectroscopy, Mask-multi-object spectroscopy, Slit-less multi-object spectroscopy, Fast Photometry and Fast short-slit spectroscopy. It will be installed at the Nasmyth-B focal station at Day One, but it will also be designed to operate at the Folded Cassegrain focal station. The physical configuration of the instrument consists of a front section where the focal plane components are mounted (Slit Unit) and a rear section with the rest of the components (Field Lens, Prism/Grism/VPH Wheel, Filter Wheel, Collimator, Camera, Folder Mirrors, Shutter and Cryostat with the detector). Both sections are connected through a hexapod type structure. The optical path is bent twice with the two folder mirrors providing a compact system. The design phase of the ELMER Structure and Mechanisms finished on November 2002. Procurement and manufacturing covered from December 2002 to June 2003. Mechanical and electrical integration was accomplished on September 2003. Test campaign at factory covered from the end of September to mid November. Critical performance of the mechanics has been carefully tested during this period: positional tolerances of optical interfaces, repeatability of the 5 mechanisms (4 rotating wheels and collimator linear stage) and deflections of the instrument due to gravity. Results from the tests are widely within the specified values, providing a top performance instrument.

We present long-slit observations in the optical and near infrared of eight HII regions in the spiral galaxy NGC 4258. Six of the observed regions are located in the SE inner spiral arms and the other two are isolated in the northern outer arms. A detailed analysis of the physical conditions of the gas has been performed. For two of the regions, an electron temperature has been derived from the [SIII] 6312 A line. For the rest, an empirical calibration based on the red and near infrared sulphur lines has been used. The oxygen abundances derived by both methods are found to be significantly lower (by a factor of two) than previously derived by using empirical calibrations based on the optical oxygen lines. In the brightest region, 74C, the observation of a prominent feature due to Wolf-Rayet stars provides an excellent constraint over some properties of the ionizing clusters. In the light of the current evolutionary synthesis models, no consistent solution is found to explain at the same time both the WR feature characteristics and the emission line spectrum of this region. In principle, the presence of WR stars could lead to large temperature fluctuations and also to a hardening of the ionizing radiation. None of these effects are found in region 74C for which the electron temperatures found from the [SIII] 6312A and the Paschen discontinuity at 8200A are equal within the errors and the effective temperature of the ionizing radiation is estimated at around 35,300K. Both more observations of confirmed high metallicity regions and a finer metallicity grid for the evolutionary synthesis models are needed in order to understand the ionizing populations of HII regions., 16 pages, 16 figures. To appear in MNRAS

This is an electronic version of an article published in The Astrophysical Journal Supplement Series. Garcia Vargas, M.L. and A.I. Diaz. Evolutionary models for high-metallicity giant extragalactic H II regions. The Astrophysical Journal Supplement Series 91 (1994): 553-581

In the frame of the Starburst Model for AGN, we show that the evolution of a massive stellar cluster in a high metallicity environment can reproduce the observed equivalent widths of Ca II triplet lines in absorption in Starburst and active galactic nuclei. In the case of Starburst galaxies, this strength, together with the emission-line ratio [O II]/[O III],can be used to determine the age of the cluster. The strength of the Ca II lines is mainly governed by the age of the stellar cluster through the presence of red supergiant stars.

We report IUE observations of two extremely low metallicity HII galaxies. Lyman alpha emission was detected in both galaxies.

We report the observation of a prominent Wolf-Rayet feature in the high excitation H II region 74C (Courtés et al. 1993) of the spiral galaxy NGC4258. In order to reproduce the observed HeII λ4686 Å line luminosity, around 38 Wolf-Rayet stars in this region are needed.

The spectral energy distribution of the Seyfert type-2 galaxy Mk 348 is analyzed based on IUE observations and published data. It is found that most of the optical and near-IR flux comes from the underlying galaxy bulge population. The rest of the emission can be fitted by a power law of the formF v ∼v −α with α=0.6. In order to explain the X-ray emission this power law requires either a change of slope or a cutoff before 2 keV. The possibility that the emission originates in a young star cluster is discussed and a simple population synthesis model for the continuum of the galaxy is presented.

This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. Terlevich, E., Díaz, A.I., Terlevich, R., González-Delgado, R.M., Pérez, E. and M.L. García Vargas. A spectroscopic search for red supergiants in the M33 giant H II region NGC 604. Monthly Notices of the Royal Astronomical Society 279 (1996): 1219-1234

This is an electronic version of an article published in The Astrophysical Journal. Gonzalez-Delgado, R.M. et al. Violent star formation in NGC 2363. The Astrophysical Journal 437 (1994): 239-261