Papers by Manuel Maldonado
Ground-based and Airborne Instrumentation for Astronomy IX
EIFIS (Extreme Integral FIeld Spectrograph) is a modular integral field spectrograph, based on im... more EIFIS (Extreme Integral FIeld Spectrograph) is a modular integral field spectrograph, based on image slicers, and makes use of new, large format detectors. The concept is thought to cover the largest possible field of view while producing spectroscopy over the complete optical range (3 000 -10 000 Å) at a medium resolving power of ∼2400. In the optimal concept, each module covers a field of view of 38" x 38" with 0.3" spaxels, which is fed into a double spectrograph with common collimator optics. The blue arm covers the spectral range between 3000 and 5600 Å and the red arm between 5400 and 10100 Å, allowing for an overlap range. The spectra are imaged onto 9.2k x 9.2k detectors using a double pseudoslit. The proposed design for the 10.4m Gran Telescopio Canarias uses a total of 6 such modules to cover a total of 2.43 square arcminutes. Here we will present the conceptual design of the instrument and a feasibility study of the optical and mechanical design of the spectrographs. We discuss the limitations and alternative designs and its potential to produce leading edge science in the era of extremely large telescopes and the James Webb Space Telescope.
… de Astronomia y …, 2007
Ground-based and Airborne Instrumentation for Astronomy VI, 2016
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Inte... more MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) for the GTC 10.4m telescope. The spectrograph is currently being integrated in the laboratory for a pre-shipping review in September 2016. This paper presents the current status and final performance of the spectrograph mechanics and opto-mechanics, composed of the mechanisms and the large optomechanical elements mounts.
Elmer Mechanics: Manufacturing, Integration and Testing
Revista Mexicana de …
Ground-based and Airborne Instrumentation for Astronomy VII, 2018
On June 25th 2017, the new intermediate-resolution optical IFU and MOS of the 10.4-m GTC had its ... more On June 25th 2017, the new intermediate-resolution optical IFU and MOS of the 10.4-m GTC had its first light. As part of the tests carried out to verify the performance of the instrument in its two modes (IFU & MOS) and 18 spectral setups (identical number of VPHs with resolutions R=6000-20000 from 0.36 to 1 micron) a number of astronomical objects were observed. These observations show that MEGARA@GTC is called to fill a niche of high-throughput, intermediateresolution IFU & MOS observations of extremely-faint narrow-lined objects. Lyman-α absorbers, star-forming dwarfs or even weak absorptions in stellar spectra in our Galaxy or in the Local Group can now be explored to a new level. Thus, the versatility of MEGARA in terms of observing modes and spectral resolution and coverage will allow GTC to go beyond current observational limits in either depth or precision for all these objects. The results to be presented in this talk clearly demonstrate the potential of MEGARA in this regard.
En esta comunicación resumimos las características y estado del proyecto del instrumento MEGARA (... more En esta comunicación resumimos las características y estado del proyecto del instrumento MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía), la futura Unidad de Campo Integral (IFU) y Espectrógrafo Multi-Objeto (MOS)ópticos para el telescopio GTC de 10.4 m. MEGARA está siendo construido por un consorcio de instituciones liderado
SPIE Proceedings, 2012
In these proceedings we give a summary of the characteristics and current status of the MEGARA in... more In these proceedings we give a summary of the characteristics and current status of the MEGARA instrument, the future optical IFU and 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). The MEGARA IFU includes two different fiber bundles, one called LCB (Large Compact Bundle) with a field-of-view of 12.5×11.3 arcsec 2 and a spaxel size of 0.62 arcsec yielding spectral resolutions between R=6,800-17,000 and another one called SCB (Small Compact Bundle) covering 8.5×6.7 arcsec 2 with hexagonally-shaped and packed 0.42-arcsec spaxels and resolutions R=8,000-20,000. The MOS component allows observing up to 100 targets in 3.5×3.5 arcmin 2. Both the IFU bundles and the set of 100 robotic positioners of the MOS will be placed at one of the GTC Folded-Cass foci while the spectrographs (one in the case of the MEGARA-Basic concept) will be placed at the Nasmyth platform. On March 2012 MEGARA passed the Preliminary Design Review and its first light is expected to take place at the end of 2015.
Ground-based and Airborne Instrumentation for Astronomy V, 2014
MEGARA is the future integral-field and multi-object spectrograph for the GTC 10.4m telescope loc... more MEGARA is the future integral-field and multi-object spectrograph for the GTC 10.4m telescope located in the Observatorio del Roque de los Muchachos in La Palma. INAOE is a member of the MEGARA Consortium and it is in charge of the Optics Manufacturing work package. In addition to the manufacturing of 73 elements, the work package includes the opto-mechanics i.e. the opto-mechanical design, manufacture, tests and integration of the complete assembly of the main optics composed by the collimator and camera subsystems. MEGARA passed the Optics Detailed Design Review in May 2013 and will have the Detailed Design Review of the complete instrument early 2014. Here we describe the detailed design of the collimator and camera barrels. We also present the finite elements models developed to simulate the behavior of the barrel, sub-cells and other mechanical elements. These models verify that the expected stress fields and the gravitational displacements on the lenses are compatible with the optical quality tolerances. The design is finished and ready for fabrication.
Ground-based and Airborne Instrumentation for Astronomy IV, 2012
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the future optical Inte... more MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) 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.
Revista Mexicana de …
Elmer es un instrumentoóptico multi-propósito para el GTC que ha sido diseñado y gestionado dentr... more Elmer es un instrumentoóptico multi-propósito para el GTC que ha sido diseñado y gestionado dentro de la Oficina de Proyecto. En esta contribución se presentan tanto la descripción general del proyecto instrumental (alcance, organización, calendario y presupuesto global) como un resumen de las prestaciones científicas del instrumento para los diferentes modos de observación.
Ground-based and Airborne Instrumentation for Astronomy VII, 2018
MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio... more MEGARA is the new generation IFU and MOS optical spectrograph built for the 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) and UPM (Spain). The instrument arrived to GTC on March 28 th 2017 and was successfully integrated and commissioned at the telescope from May to August 2017. During the on-sky commissioning we demonstrated that MEGARA is a powerful and robust instrument that provides on-sky intermediate-to-high spectral resolutions R FWHM ~ 6,000, 12,000 and 20,000 at an unprecedented efficiency for these resolving powers in both its IFU and MOS modes. The IFU covers 12.5 x 11.3 arcsec 2 while the MOS mode allows observing up to 92 objects in a region of 3.5 x 3.5 arcmin 2. In this paper we describe the instrument main subsystems, including the Folded-Cassegrain unit, the fiber link, the spectrograph, the cryostat, the detector and the control subsystems, and its performance numbers obtained during commissioning where the fulfillment of the instrument requirements is demonstrated.
MEGARA is an IFU & MOS medium-resolution spectrograph that finished its commissioning at the GTC ... more MEGARA is an IFU & MOS medium-resolution spectrograph that finished its commissioning at the GTC 10m telescope on August 2017. MEGARA is a fiber-fed high-resolution spectrograph with two major units, Fiber-MOS & Spectrograph, that are now located at the Folded-Cass F and Nasmyth-A foci of GTC respectively. These are linked by more than 1200 fibers 44.5m-length split between two observing modes, the LCB (Integral Field Unit, IFU) and a Multi- Object (MOS) capability with 92 robotic positioners each one provided with a mini-bundle of 7 fibers. The spectrograph can accommodate 18 VPHs (11 of them can be simultaneously mounted) covering the visible wavelength range at Resolving Powers between R=6000-20000. This paper presents the sequence of tasks carried out after Laboratory Acceptance at the Universidad Complutense de Madrid to move the whole instrument to the GTC. A detailed day-to-day plan was followed to disassemble, pack, transport, reintegrate the full instrument at the GTC and t...
22nd Congress of the International Commission for Optics: Light for the Development of the World, 2011
This paper presents the opto-mechanical design of a novel spectroscopic element-sliced pupil grat... more This paper presents the opto-mechanical design of a novel spectroscopic element-sliced pupil grating-that allows increasing the spectral resolution while keeping the instrument geometry. The concept is based on "cutting" the pupil into different slices by placing a number of prisms at the two sites of a VPH grating. The independent beams are guided through a precise opto-mechanical assembly to assure the recombination of the individual images on the detector within the available error budget, producing a single spectrum. To probe the feasibility of the concept, we have designed and manufactured a 3-slice prototype for an already-built spectrograph (Elmer, for the GTC 10-m telescope).
Ground-based and Airborne Instrumentation for Astronomy V, 2014
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Fie... more MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the GTC 10.4m telescope in La Palma. MEGARA offers two IFU fiber bundles, one covering 12.5x11.3 arcsec 2 with a spaxel size of 0.62 arcsec (Large Compact Bundle; LCB) and another one covering 8.5x6.7 arcsec 2 with a spaxel size of 0.42 arcsec (Small Compact Bundle; SCB). The MEGARA MOS mode will allow observing up to 100 objects in a region of 3.5x3.5 arcmin 2 around the two IFU bundles. Both the LCB IFU and MOS capabilities of MEGARA will provide intermediate-to-high spectral resolutions (R FWHM~6 ,000, 12,000 and 18,700, respectively for the low-, mid-and high-resolution Volume Phase Holographic gratings) in the range 3650-9700ÅÅ. These values become R FWHM~7 ,000, 13,500, and 21,500 when the SCB is used. A mechanism placed at the pseudo-slit position allows exchanging the three observing modes and also acts as focusing mechanism. The spectrograph is a collimator-camera system that has a total of 11 VPHs simultaneously available (out of the 18 VPHs designed and being built) that are placed in the pupil by means of a wheel and an insertion mechanism. The custom-made cryostat hosts an E2V231-84 4kx4k CCD. The UCM (Spain) leads the MEGARA Consortium that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). MEGARA is being developed under a contract between GRANTECAN and UCM. The detailed design, construction and AIV phases are now funded and the instrument should be delivered to GTC before the end of 2016.
Elmer es un instrumento para el GTC diseñado para observar en el intervalo espectral entre 365 y ... more Elmer es un instrumento para el GTC diseñado para observar en el intervalo espectral entre 365 y 1000 nm. Los modos de observación para Día Uno son: Imagen, Espectroscopía de rendija larga y multi-objeto, Espectroscopía sin rendija, Fotometría rápida y Espectroscopía rápida con rendija corta; en un campo de 4.2 arcmin de diámetro. Elmer dispone de resoluciones espectrales de 250, 1000 y 2500, cubriendo todo el intervalo de longitud de onda. Elmer ha sido diseñado y gestionado en la Oficina de Proyecto de GTC. El instrumento se encuentra en las fases finales de pruebas previas a su envío al ORM. En esta contribución se da una descripción general y un resumen de sus prestaciones científicas ABSTRACT 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 multiobject 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.
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Papers by Manuel Maldonado