Performance of MEGARA spectrograph optical elements

Carrasco, E.; Паез, Гонзало; Izazaga-Pérez, Rafael; Hurtado, J. de la Luz; Pérez, Carlos Mazo; Granados, Francisca López; Aguirre-Aguirre, Daniel; Percino, E.; Reyes, Javier Escalera; Paz, A. Gil de; Gallego, J.; Iglesias, Jorge Mario Ortega

doi:10.1117/12.2232208

Cited by 6 publications

(9 citation statements)

References 7 publications

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“…As shown in Figure 7, the angle between the collimator and the camera is fixed to 68º. Details on the optical design are given in other publications 2,3,9,15,16,17 . All camera lenses have been manufactured at INAOE (Mexico).…”

Section: Cameramentioning

confidence: 99%

“…The VPHs are inserted in the pupil by means of an insertion mechanism that extracts the VPH from a wheel where up to a total of 11 VPHs can be placed (out of the 6 LR + 10 MR + 2 HR = 18 VPHs built; a number of MR VPHs are still being manufactured), both responsibility of AVS (Spain). More details on the MEGARA spectrograph optical and optomechanical design and manufacturing are given in this same volume 2,3,8,9,10,11,14,15,16,17 . The camera focuses the light onto an E2V 231-84 deep-depleted 4kx4k 15-μm pixels CCD 18 located in a cryostat designed and built by the INAOE 19,20 .…”

Section: Overviewmentioning

confidence: 99%

“…Category (1) includes the study of Planetary Nebulae, nearby galaxies, and the high-redshift IGM and category (2) Galactic open stellar clusters, resolved stellar populations in Local Group galaxies, intermediate-redshift dwarf and starburst galaxies, and high-redshift cluster galaxies. The MEGARA Science Team encompasses researchers with broad range of interests that belong to institutions of all members of the GTC community (Spain, Mexico and UF).…”

Section: Megara Sciencementioning

confidence: 99%

“…The MEGARA Fiber-MOS is designed to study point sources with high number densities (such as RGB stars in LG galaxies) as it allows reaching densities as high as 8 objects per arcmin 2 . This fact along with the short reconfiguration time of Fiber-MOS robotic positioners (<1min; see Section 4) makes of MEGARA a unique tool for the study of large numbers of sources in this kind of targets.…”

Section: Megadesmentioning

confidence: 99%

“…Section 11 provides more details on the status of system AIV and results of the laboratory tests performed during this phase. We refer the reader to other publications in this volume 1,2,3,4,5,6,7,8,9,10,11,12 for further details.…”

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confidence: 99%

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MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

et al. 2016

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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 that is being built by a Consortium led by UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain), and UPM (Spain). The instrument is currently finishing AIV and will be sent to GTC on November 2016 for its on-sky commissioning on April 2017. The MEGARA IFU fiber bundle (LCB) covers 12.5x11.3 arcsec 2 with a spaxel size of 0.62 arcsec while the MEGARA MOS mode allows observing up to 92 objects in a region of 3.5x3.5 arcmin 2 around the IFU.The IFU and MOS modes of MEGARA will provide identical 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 3700-9800ÅÅ. An x-y mechanism placed at the pseudo-slit position allows (1) exchanging between the two observing modes and (2) focusing the spectrograph for each VPH setup. 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 a 4kx4k 15-μm CCD. The unique characteristics of MEGARA in terms of throughput and versatility and the unsurpassed collecting are of GTC make of this instrument the most efficient tool to date to analyze astrophysical objects at intermediate spectral resolutions.In these proceedings we present a summary of the instrument characteristics and the results from the AIV phase. All subsystems have been successfully integrated and the system-level AIV phase is progressing as expected.

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Section: Cameramentioning

confidence: 99%

Section: Overviewmentioning

confidence: 99%

Section: Megara Sciencementioning

confidence: 99%

Section: Megadesmentioning

confidence: 99%

mentioning

confidence: 99%

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MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

et al. 2016

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The MEGARA view of outflows in LINERs

Hermosa Muñoz,

Cazzoli,

Márquez

et al. 2024

A&A

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Feedback processes, in particular those driven by outflows, are believed to play a major role in galaxy evolution. Outflows are believed to be ubiquitous in all active galactic nuclei (AGNs), although their presence in low luminosity AGNs, in particular for Low-Ionisation Nuclear Emission line Regions (LINERs), has only started to be explored. Their properties (geometry, mass, and energetics) are still far from being properly characterised. The main goal is to use integral field spectroscopic data from the MEGARA instrument at the Gran Telescopio Canarias (GTC) to analyse a small sample of nine LINERs, candidates of hosting ionised gas outflows. We aim to study the main emission lines in the optical wavelength range to identify their properties and physical origin. We obtained data cubes in several bands at the lowest (Rsim 6000) and highest (Rsim 20000) spectral resolution of MEGARA. We modelled and subtracted the stellar continuum to obtain the ionised gas contribution, and then fitted the emission lines to extract their kinematics (velocity and velocity dispersion). We identified outflows as a secondary component in the emission lines and obtained their main properties. The primary component of the emission lines was typically associated with gas in the galactic disc. For some objects, there is an enhanced-sigma region typically co-spatial with the secondary component. We associated it to turbulent gas produced due to the interaction with the outflows. We find signatures of outflows in six LINERs, with mass outflow rates ranging from 0.004 to 0.4 $M_ sun $ and energy rates from sim \,1038 to sim $, extending to distances of sim \,400\,pc at an (absolute) velocity of sim $ (on average). They tend to be compact and unresolved, although for some sources they are extended with a bubble-like morphology. Our results confirm the existence of outflows in the best LINER candidates identified using previous long-slit spectroscopic and imaging data. These outflows do not follow the scaling relations obtained for more luminous AGNs. For some objects we discuss jets as the main drivers of the outflows.

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MEGARA Optics: Sub-aperture Stitching Interferometry for Large Surfaces

Aguirre-Aguirre

Carrasco

Izazaga-Pérez

et al. 2018

PASP

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In this work, we present a detailed analysis of sub-aperture interferogram stitching software to test circular and elliptical clear apertures with diameters and long axes up to 272 and 180 mm, respectively, from the Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía (MEGARA). MEGARA is a new spectrograph for the Gran Telescopio Canarias (GTC). It offers a resolution between 6000 and 20000 via the use of volume phase holographic gratings. It has an integral field unit and a set of robots for multi-object spectroscopy at the telescope focal plane. The output end of the fibers forms the spectrograph pseudo-slit. The fixed geometry of the collimator and camera configuration requires prisms in addition to the flat windows of the volume phase holographic gratings. There are 73 optical elements of large aperture and high precision manufactured in Mexico at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE) and the Centro de Investigaciones en Óptica (CIO). The principle of stitching interferometry is to divide the surface being tested into overlapping small sections, which allows an easier analysis (Kim & Wyant 1981). This capability is ideal for non-contact tests for unique and large optics as required by astronomical instruments. We show that the results obtained with our sub-aperture stitching algorithm were consistent with other methods that analyze the entire aperture. We used this method to analyze the 24 MEGARA prisms that could not be tested otherwise. The instrument has been successfully commissioned at GTC in all the spectral configurations. The fulfillment of the irregularity specifications was one of the necessary conditions to comply with the spectral requirements.

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Performance of MEGARA spectrograph optical elements

Cited by 6 publications

References 7 publications

MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

MEGARA, the new intermediate-resolution optical IFU and MOS for GTC: getting ready for the telescope

The MEGARA view of outflows in LINERs

MEGARA Optics: Sub-aperture Stitching Interferometry for Large Surfaces

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