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Perez-Calpena A.,FRACTAL SLNE | Seifert W.,LSW | Amado P.,IAA | Quirrenbach A.,LSW | And 9 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

CARMENES is a high resolution spectrograph built for the 3.5m telescope at the Calar Alto Observatory by a consortium formed by 11 German and Spanish institutions. CARMENES is composed by two separated highly stabilized spectrographs covering the VIS and NIR wavelength ranges to provide high-Accuracy radial-velocity measurements with long-Term stability. The technical and managerial complexity of the instrument, with a fixed project deadline, demanded a strong system engineering control to preserve the high level requirements during the development, manufacturing, assembly, integration and verification phases. © 2016 SPIE.


Carrasco E.,National Institute of Astrophysics, Optics and Electronics | Sanchez-Blanco E.,Fractal SLNE | Garcia Vargas M.L.,Fractal SLNE | Gil De Paz A.,Complutense University of Madrid | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

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. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Garcia-Vargas M.L.,Fractal slne | Molla M.,CIEMAT | Martin-Manjon M.L.,Autonomous University of Madrid
Monthly Notices of the Royal Astronomical Society | Year: 2013

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 resulting from our POPSTAR code. Colours in the Johnson and Sloan Digital Sky Survey (SDSS) systems, Hα and Hβ luminosities and equivalent widths, and ionizing 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 calculate the evolution of the cluster and the region geometry in a consistent manner. We demonstrate the importance of the contribution of emission lines to broader band photometry when characterizing 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 ionizing cluster, when only photometric observations are available; for an isolated starforming region, the young star cluster models can be used, free from the contamination of any underlying background stellar population. In most cases, however, the ionizing 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 (SEDs), and the derived colours for mixed populations where an underlying host population is combined in different mass-ratios with a recent ionizing burst. These colours, together with other common photometric parameters, such as theHa radius of the ionized region, and Balmer line equivalent widths and luminosities, allow one to infer the physical properties of star-forming regions even in the absence of spectroscopic information. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


Sanchez-Janssen R.,European Southern Observatory | Amorin R.,Institute Astrofisica Of Andalucia Csic | Garcia-Vargas M.,FRACTAL SLNE | Gomes J.M.,University of Porto | And 13 more authors.
Astronomy and Astrophysics | Year: 2013

Context. Even though they are by far the most abundant of all galaxy types, the detailed properties of dwarf galaxies are still only poorly characterised-especially because of the observational challenge that their intrinsic faintness and weak clustering properties represent. Aims. AVOCADO aims at establishing firm conclusions on the formation and evolution of dwarf galaxies by constructing and analysing a homogeneous, multiwavelength dataset for a statistically significant sample of approximately 6500 nearby dwarfs (Mi-5 log h100 >-18 mag). The sample is selected to lie within the 20 < D < 60 h100 -1 Mpc volume covered by the SDSS-DR7 footprint, and is thus volume-limited for Mi-5 log h100 <-16 mag dwarfs-but includes ≈1500 fainter systems. We will investigate the roles of mass and environment in determining the current properties of the different dwarf morphological types-including their structure, their star formation activity, their chemical enrichment history, and a breakdown of their stellar, dust, and gas content. Methods. We present the sample selection criteria and describe the suite of analysis tools, some of them developed in the framework of the Virtual Observatory. We use optical spectra and UV-to-NIR imaging of the dwarf sample to derive star formation rates, stellar masses, ages, and metallicities-which are supplemented with structural parameters that are used to classify them morphologically. This unique dataset, coupled with a detailed characterisation of each dwarf's environment, allows for a fully comprehensive investigation of their origins and enables us to track the (potential) evolutionary paths between the different dwarf types. Results. We characterise the local environment of all dwarfs in our sample, paying special attention to trends with current star formation activity. We find that virtually all quiescent dwarfs are located in the vicinity (projected distances ≤ 1.5 h100 -1 Mpc) of a≥ L* companions, consistent with recent results. While star-forming dwarfs are preferentially found at separations of the order of 1 h100 -1 Mpc, there appears to be a tail towards low separations (≤ 100 h100 -1 kpc) in the distribution of projected distances. We speculate that, modulo projection effects, this probably represents a genuine population of late-type dwarfs caught upon first infall about their host and before environmental quenching has fully operated. In this context, these results suggest that internal mechanisms-such as gas exhaustion via star formation or feedback effects-are not sufficient to completely cease the star formation activity in dwarf galaxies, and that becoming the satellite of a massive central galaxy appears to be a necessary condition to create a quiescent dwarf. © 2013 ESO.


Martin-Manjon M.L.,Autonomous University of Madrid | Garcia-Vargas M.L.,FRACTAL SLNE | Garcia-Vargas M.L.,Institute of Astrophysics of Canarias | Molla M.,CIEMAT | Diaz A.I.,Autonomous University of Madrid
Monthly Notices of the Royal Astronomical Society | Year: 2010

This is the second paper of a series reporting the results from the popstar evolutionary synthesis models. Here, we present synthetic emission-line spectra of H ii regions photoionized by young star clusters, for seven values of cluster masses and for ages between 0.1 and 5.2 Myr. The ionizing spectral energy distributions (SEDs) are those obtained by the popstar code for six different metallicities, with a very low-metallicity set,Z = 0.0001, not included in previous similar works. We assume that the radius of the H ii region is the distance at which the ionized gas is deposited by the action of the mechanical energy of the winds and supernovae from the central ionizing young cluster. In this way, the ionization parameter is eliminated as free argument, since now its value is obtained from the cluster physical properties (mass, age and metallicity) and from the gaseous medium characteristics (density and abundances). We discuss our results and compare them with those from previous models and also with a large data set of giant H ii regions for which abundances have been derived in a homogeneous manner. The values of the [O iii] lines (at λλ 4363, 4959, 5007 Å) in the lowest metallicity nebulae are found to be very weak and similar to those coming from very high-metallicity regions (solar or oversolar). Thus, the sole use of the oxygen lines is not enough to distinguish between very low and very high metallicity regions. In these cases, we emphasize the need of the additional support of alternative metallicity tracers, like the [S iii] lines in the near-infrared. © 2010 The Authors. Journal compilation © 2010 RAS.


Garcia-Vargas M.L.,FRACTAL SLNE | Perez-Calpena A.,FRACTAL SLNE | Gallego J.,Complutense University of Madrid | Gil De Paz A.,Complutense University of Madrid | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

The goal of VIENTOS project is to analyze pupil innovative systems that could be used in the new generation of instruments for the large telescopes. This study tries to identify the current scientific needs, to understand why some of them have not been fulfilled yet (due to pre-conceived technical ideas or to managerial reasons) and to propose optomechanical solutions for these pupil elements that could produce a qualitative leap in the performance of the instruments to operate in the large telescopes. VIENTOS is currently on-going as a collaborative project between FRACTAL and the University Complutense of Madrid (UCM) and is being partially funded by a CDTI grant under the program Industry for Science. CDTI is the Development and Industrial Transfer Center from the Minister of Science and Innovation (Spain). Among the different innovative systems that we have carried out, our team has explored potential solutions for narrow band Imaging with tunable filters in the near-IR and a novel pupil system called sliced-pupil grating, a device designed for increasing the spectral resolution in astronomical spectrographs, without changing the geometry of the main optics. Nanotechnology customized filters to be applicable to astronomical systems are under study. © 2012 SPIE.


Perez-Calpena A.,FRACTAL SLNE | Arrillaga X.,AVS | Gil De Paz A.,Complutense University of Madrid | Sanchez-Blanco E.,FRACTAL SLNE | And 6 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for GTC. The Fiber Units are placed at one Folded Cassegrain focus and feed the spectrograph located on a Nasmyth-type platform. This paper summarizes the status of the design of the MEGARA Folded Cassegrain Subsystems after the PDR (held on March 2012), as well as the prototyping that has been carried out during this phase. The MEGARA Fiber Unit has two IFUs: a Large Compact Bundle covering 12.5 arcsec x 11.3 arcsec on sky (100 microns fiber-core), and a Small Compact Bundle, of 8.5 arcsec x 6.7 arcsec (70 microns fiber-core), plus a Fiber MOS positioner, able to place up to 100 mini-bundles 7 fibers each (100 microns fiber-core) in MOS configuration within a 3.5arcmin x 3.5arcmin FOV. A field lens provides a telecentric focal plane where the fibers are located. Microlens arrays couple the telescope beam to the collimator focal ratio at the entrance of the fibers (providing the f/17 to f/3 focal ratio reduction to enter into the fibers). Finally, the fibers, organized in bundles, end in the pseudo-slit plate, which will be placed at the entrance focal plane of the MEGARA spectrographs. © 2012 SPIE.


Tulloch S.,FRACTAL SLNE | Gil De Paz A.,Complutense University of Madrid | Gallego J.,Complutense University of Madrid | Zamorano J.,Complutense University of Madrid | Tapia C.,Complutense University of Madrid
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

A CCD test-bench has been built at the Universidad Complutense's LICA laboratory. It is initially intended for commissioning of the MEGARA1 (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) instrument but can be considered as a general purpose scientific CCD test-bench. The test-bench uses an incandescent broad-band light source in combination with a monochromator and two filter wheels to provide programmable narrow-band illumination across the visible band. Light from the monochromator can be directed to an integrating sphere for flat-field measurements or sent via a small aperture directly onto the CCD under test for high accuracy diode-mode quantum efficiency measurements. Point spread function measurements can also be performed by interposing additional optics between sphere and the CCD under test. The whole system is under LabView control via a clickable GUI. Automated measurement scans of quantum efficiency can be performed requiring only that the user replace the CCD under test with a calibrated photodiode after each measurement run. A 20cm diameter cryostat with a 10cm window and Brooks Polycold PCC closed-cycle cooler also form part of the test-bench. This cryostat is large enough to accommodate almost all scientific CCD formats has initially been used to house an E2V CCD230 in order to fully prove the test-bench functionality. This device is read-out using an Astronomical Research Camera controller connected to the UKATC's UCAM data acquisition system. © 2012 SPIE.


Perez-Calpena A.,Fractal Slne | Garcia-Vargas M.L.,Fractal Slne | Gil De Paz A.,Complutense University of Madrid | Gallego Maestro J.,Complutense University of Madrid | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) 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 Politécnica 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. © 2014 SPIE.


Garcia-Vargas M.L.,FRACTAL SLNE | Mujica-Alvarez E.,FRACTAL SLNE | Perez-Calpena A.,FRACTAL SLNE
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

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. © 2012 SPIE.

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