Exo-Planets search and characterization has been the science case driving the SHARK-NIR design, which is one of the two coronagraphic instruments proposed for the Large Binocular Telescope. In fact, together with SHARK-VIS (working in the visible domain), it will offer the possibility to do binocular observations combining direct imaging, coronagraphic imaging and coronagraphic low resolution spectroscopy in a wide wavelength domain, going from 0.5μm to 1.7μm. Additionally, the contemporary usage of LMIRCam, the coronagraphic LBTI NIR camera, working from K to L band, will extend even more the covered wavelength range. The instrument has been designed with two intermediate pupil planes and three focal planes, in order to give the possibility to implement a certain number of coronagraphic techniques, with the purpose to select a few of them matching as much as possible the requirements of the different science cases in terms of contrast at various distances from the star and in term of required field of view. SHARK-NIR has been approved by the LBT board in June 2017, and the procurement phase started just after. We report here about the project status, which is currently at the beginning of the AIV phase at INAF-Padova, and should last about one year. Even if exo-planets is the main science case, the SOUL upgrade of the LBT AO will increase the instrument performance in the faint end regime, allowing to do galactic (jets and disks) and extra-galactic (AGN and QSO) science on a relatively wide sample of targets, normally not reachable in other similar facilities.
Residual speckles in adaptive optics (AO) images represent a well-known limitation on the achievement of the contrast needed for faint source detection. Speckles in AO imagery can be the result of either residual atmospheric aberrations, not corrected by the AO, or slowly evolving aberrations induced by the optical system. We take advantage of the high temporal cadence (1 ms) of the data acquired by the System for Coronagraphy with High-order Adaptive Optics from R to K bands-VIS forerunner experiment at the Large Binocular Telescope to characterize the AO residual speckles at visible wavelengths. An accurate knowledge of the speckle pattern and its dynamics is of paramount importance for the application of methods aimed at their mitigation. By means of both an automatic identification software and information theory, we study the main statistical properties of AO residuals and their dynamics. We therefore provide a speckle characterization that can be incorporated into numerical simulations to increase their realism and to optimize the performances of both real-time and postprocessing techniques aimed at the reduction of the speckle noise.
SHARK-NIR channel is one of the two coronagraphic instruments proposed for the Large Binocular Telescope, in the framework of the call for second generation instruments, issued in 2014. Together with the SHARK-VIS channel, it will offer a few observing modes (direct imaging, coronagraphic imaging and coronagraphic low resolution spectroscopy) covering a wide wavelength domain, going from 0.5μm to 1.7μm.
Initially proposed as an instrument covering also the K-band, the current design foresees a camera working from Y to H bands, exploiting in this way the synergy with other LBT instruments such as LBTI, which is actually covering wavelengths greater than L' band, and it will be soon upgraded to work also in K band. SHARK-NIR has been undergoing the conceptual design review at the end of 2015 and it has been approved to proceed to the final design phase, receiving the green light for successive construction and installation at LBT.
The current design is significantly more flexible than the previous one, having an additional intermediate pupil plane that will allow the usage of coronagraphic techniques very efficient in term of contrast and vicinity to the star, increasing the instrument coronagraphic performance. The latter is necessary to properly exploit the search of giant exo-planets, which is the main science case and the driver for the technical choices of SHARK-NIR. We also emphasize that the LBT AO SOUL upgrade will further improve the AO performance, making possible to extend the exo-planet search to target fainter than normally achieved by other 8-m class telescopes, and opening in this way to other very interesting scientific scenarios, such as the characterization of AGN and Quasars (normally too faint to be observed) and increasing considerably the sample of disks and jets to be studied.
Finally, we emphasize that SHARK-NIR will offer XAO direct imaging capability on a FoV of about 15"x15", and a simple coronagraphic spectroscopic mode offering spectral resolution ranging from few hundreds to few thousands. This article presents the current instrument design, together with the milestones for its installation at LBT.
This article presents a proposal aimed at investigating the technical feasibility and the scientific capabilities of high
contrast cameras to be implemented at LBT. Such an instrument will fully exploit the unique LBT capabilities in
Adaptive Optics (AO) as demonstrated by the First Light Adaptive Optics (FLAO) system, which is obtaining excellent
results in terms of performance and reliability. The aim of this proposal is to show the scientific interest of such a
project, together with a conceptual opto-mechanical study which shows its technical feasibility, taking advantage of the
already existing AO systems, which are delivering the highest Strehl experienced in nowadays existing telescopes.
Two channels are foreseen for SHARK, a near infrared channel (2.5-0.9 um) and a visible one (0.9 – 0.6 um), both
providing imaging and coronagraphic modes. The visible channel is equipped with a very fast and low noise detector
running at 1.0 kfps and an IFU spectroscopic port to provide low and medium resolution spectra of 1.5 x 1.5 arcsec
fields.
The search of extra solar giant planets is the main science case and the driver for the technical choices of SHARK, but
leaving room for several other interesting scientific topics, which will be briefly depicted here.
C. Evans, M. Puech, B. Barbuy, P. Bonifacio, J.-G. Cuby, E. Guenther, F. Hammer, P. Jagourel, L. Kaper, S. Morris, J. Afonso, P. Amram, H. Aussel, A. Basden, N. Bastian, G. Battaglia, B. Biller, N. Bouché, E. Caffau, S. Charlot, Y. Clénet, F. Combes, C. Conselice, T. Contini, G. Dalton, B. Davies, K. Disseau, J. Dunlop, F. Fiore, H. Flores, T. Fusco, D. Gadotti, A. Gallazzi, E. Giallongo, T. Gonçalves, D. Gratadour, V. Hill, M. Huertas-Company, R. Ibata, S. Larsen, O. Le Fèvre, B. Lemasle, C. Maraston, S. Mei, Y. Mellier, G. Östlin, T. Paumard, R. Pello, L. Pentericci, P. Petitjean, M. Roth, D. Rouan, D. Schaerer, E. Telles, S. Trager, N. Welikala, S. Zibetti, B. Ziegler
Over the past 18 months we have revisited the science requirements for a multi-object spectrograph (MOS) for the
European Extremely Large Telescope (E-ELT). These efforts span the full range of E-ELT science and include input
from a broad cross-section of astronomers across the ESO partner countries. In this contribution we summarise the key
cases relating to studies of high-redshift galaxies, galaxy evolution, and stellar populations, with a more expansive
presentation of a new case relating to detection of exoplanets in stellar clusters. A general requirement is the need for
two observational modes to best exploit the large (≥40 arcmin2) patrol field of the E-ELT. The first mode (‘high
multiplex’) requires integrated-light (or coarsely resolved) optical/near-IR spectroscopy of >100 objects simultaneously.
The second (‘high definition’), enabled by wide-field adaptive optics, requires spatially-resolved, near-IR of >10
objects/sub-fields. Within the context of the conceptual study for an ELT-MOS called MOSAIC, we summarise the toplevel
requirements from each case and introduce the next steps in the design process.
By exploiting the high strehl ratio PSF (point spread function) provided by the large binocular telescope (LBT), a high
contrast visual camera working in the range 650-700 nm can deliver impressive results with the help of a simple
coronagraph. In the framework of a feasibility study of such instrument, numerical simulations have been conducted to
assess its performances in terms of contrast enhancement in real seeing conditions. Both simulated and recorded time
series of adaptive optics residual aberrations are in fact used to estimate the contrast enhancement achieved with this
imager in different seeing conditions and with different occulting masks. The results obtained are extremely promising
and provide useful information for the detection of reflected light of Jupiter-like planets orbiting nearby stars in the range
of 5÷10 pc.
Wide field spectrograph at the largest optical telescopes will be decisive to address the main open questions in modern
astrophysics. The key feature of this instrument is the modular concept: the spectrograph is the combination of about one
thousand identical small cameras, each carrying a few slits and operating at low to moderate spectral resolution, to be
illuminated at the Cassegrain focus of an existing 8m class telescope. The dispersing element to be used in these small
cameras has to satisfy some requirements in term of efficiency, resolution, size, small series production. Moreover the
cameras have to work both in imaging and spectroscopy modes, therefore a GRISM configuration of the dispersing
element is suitable. Based on these considerations, we have focused our attention to Volume Phase Holographic Gratings
(VPHGs) since they show large peak efficiency in the target spectral range (400-800 nm), they can be arranged in a
GRISM configuration reaching relative large resolution. The main constrains concern the available room for the
dispersing element, indeed the camera design is very compact. As a consequence, slanted VPHGs are studied and
optimized in combination with normal and Fresnel prisms.
The concept of segmenting the focal plane of an existing 8m class telescope in order to fill it with an array of several fast
cameras has been developed further and in this work the status of an engineering program aimed to produce a design
qualified for the construction, and to assess its cost estimates is presented. The original concept of just having simple
cameras with all identical optical components other than a pupil plane corrector to remove the fixed aberrations at the
off-axis field of a telescope has been extended to introduce a spectroscopic capability and to assess a trade-off between a
very large number (of the order of thousand) of cameras with a small single Field of View with a smaller number of
cameras able to compensate the aberration on a much larger Field of View with a combination of different optical
elements and different ways to mount and align them.
The scientific target of a few thousands multi-slit spectra over a Field of View of a few square degrees, combined with
the ambition to mount this on an existing 8m class telescope makes the scientific rationale of such an instrument a very
interesting one. In the paper we describe the different options for a possible optical design, the trade off between
variations on the theme of the large segmentation and we describe briefly the way this kind of instrument can handle a
multi-slit configuration. Finally, the feasibility of the components and a brief description of how the cost analysis is
being performed are given. Perspectives on the construction of this spectrograph are given as well.
Since the very beginning of 2008, the Large Binocular Telescope (LBT) is officially equipped with it's first binocular
instrument ready for science observations: the Large Binocular Camera (LBC). This is a double CCD imager, installed at
the prime focus stations of the two 8.4m telescopes of LBT, able to obtain deep and wide field images in the whole
optical spectrum from UV to NIR wavelengths.
We present here the overall architecture of the instrument, a brief hardware review of the two imagers and notes how
observations are carried on. At the end we report preliminary results on the performances of the instrument along with
some images obtained during the first months of observations in binocular mode.
It is generally believed that very fast cameras imaging large Fields of View translate into huge optomechanics
and mosaics of very large contiguous CCDs. It has already been suggested that seeing limited imaging cameras
for telescopes whose diameters are larger than 20m are considered virtually impossible for a reasonable cost.
It has also been suggested that using existing technology and at a moderate price, one can build a Smart Fast
Camera, a device that placed on aberrated Field of View, including those of slow focal ratios, is able to provide
imaging at an equivalent focal ratio as low as F/1, with a size that is identical to the large focal ratio focal plane
size. The design allows for easy correction of aberrations over the Field of View. It has low weight and size
with respect to any focal reducer or prime focus station of the same performance. It can be applied to existing
8m-class telescopes to provide a wide field fast focal plane or to achieve seeing-limited imaging on Extremely
Large Telescopes. As it offers inherently fast read-out in a massive parallel mode, the SFC can be used as a
pupil or focal plane camera for pupil-plane or Shack-Hartmann wavefront sensing for 30-100m class telescopes.
Basing upon Smart Fast Camera concept, we present a study turned to explain the pliability of this instrument
for different existing telescopes.
The Large Binocular Telescope is currently equipped with a couple of wide field Prime Focus. The two cameras are optimized for, respectively, the blue and the red portion of the visible spectrum. The history of this project is here sketched up and the current status is shown. The Blue channel is currently working onboard the telescope and provided what has been named the first-light of the telescope in single eye configuration.
The Prime Focus for the Large Binocular Telescope are a couple of Prime Focus stations each equipped with four 4kx2k CCDs and a six lenses corrector with an aspheric surface and the first lens as large as roughly 800mm in diameter. These cameras will cover almost half degree of Field of View on 8m-class telescopes with unprecedented velocity of F/1.4. The two units are optimized for the Red and Blue portions of the visible wavelength and additionally an extension to J and H bands is foreseen. An overview of the project, including the optomechanics, the cryogenics, the electronics, and the software is given along with a preliminary account of lessons learned and on how much the second unit, the Red one, the schedule of which is shifted with respect to the Blue one by several months, will take advantage from the experience gained in the Blue unit assembly and integration.
The Large Binocular Camera (LBC) is the double optical imager whose blue channel is going to start the commissioning phase at the Large Binocular Telescope (2x8.4 m). We present the updated characteristics of the CCD camera and its characterization performed in the laboratory of the Rome Observatory and in the integration room of the Arcetri Observatory.
The LBC (Large Binocular Camera) Image Simulator is a package for generating artificial images in the typical FITS format. It operates on real or artificial images, simulating the expected performances of real instruments including several observing conditions (filters, air-mass, flat-field, exposure time) and creating images with the LBC instrumental artifacts (optical deformations, noise, CCD architectures). This simulator can be used also to produce artificial images for other existing and future telescopes, since it is very flexible on its structure. The main aim of LBCSIM is to support the development of pipeline and data analysis procedure able to cope with wide field imaging and fast reduction of huge amount of photometric data. The software consists of three stand alone programs written in C language, using IRAF and running under Linux OS. The LBC Image Simulator is built with particular attention to the Virtual Observatory and Data Grid applications. In this paper, we first describe the software, the performances and several tests carried out before the public release and some examples for the users. In particular, we compared the Hubble Deep Field South (HDFS) as seen by FORS1 with a simulated image and found that the agreement is good. Then, we use this software to predict the expected performances of the LBC instrument by means of realistic simulations of deep field observations with the LBT telescope.
The Large Binocular Camera (LBC) is a double prime focus station to be mounted on the Large Binocular Telescope (LBT). The two channels, called Blue and Red, are optimized for the UB and VRIZ bands respectively and are characterized by two optical correctors with very fast focal ratio (F/1.45) and challenging optical and mechanical specifications. We present here a review of the optical and mechanical design of both the optical correctors and report on the current status of the manufacturing and integration.
The Large Binocular Camera (LBC) is the double optical imager that will be installed at the prime foci of the Large Binocular Telescope (2x8.4 m). Four Italian observatories are cooperating in this project: Rome (CCD Camera), Arcetri-Padua (Optical Corrector) and Trieste (Software). LBC is composed by two separated large field (27 arcmin FOV) cameras, one optimized for the UBV bands and the second for the VRIZ bands. An optical corrector balances the aberrations induced by the fast (F#=1.14) parabolic primary mirror of LBT, assuring that the 80% of the PSF encircled energy falls inside one pixel for more of the 90% of the field. Each corrector uses six lenses with the first having a diameter of 80cm and the third with an aspherical surface. Two filter wheels allow the use of 8 filters. The two channels have similar optical designs satisfying the same requirements, but differ in the lens glasses: fused silica for the "blue" arm and BK7 for the "red" one. The two focal plane cameras use an array of four 4290 chips (4.5x2 K) provided
by Marconi optimized for the maximum quantum efficiency (85%) in each channel. The sampling is 0.23 arcseconds/pixel. The arrays are cooled by LN2 cryostats assuring 24 hours of operation. Here we present a description of the project and its current status including a report about the Blue camera and its laboratory tests. This instrument is planned to be the first light instrument of LBT.
An analysis of the galaxy evolution from deep multicolor imaging of optically and infrared selected galaxies is presented and compared with current models of galaxy formation and evolution. A very deep K=20-23) sample of optically and infrared selected galaxies from ESO/VLT and HST surveys like the HDF South, Chandra Deep Field, NTT Deep Field is being analyzed. First results are shown in terms of the high redshift rest frame UV luminosity density and rest frame blue luminosity function and compared with predictions of CDM hierarchical models for galaxy formation and evolution. The observations show an excess of bright sources at very high redshifts 5<z<6 respect to the expectations of the CDM models. At the same time the models predict too many dwarfs especially at intermediate and high redshifts. Possible explanations for these discrepancies are briefly discussed.
The large Binocular Telescope is currently in the pre- erection phase. The instrument has been already funded and its first-light is expected shortly after that of the LBT. Given the peculiarity of the telescope optics we designed tow prime focus cameras with two five-lens refractive correctors, optimized in the blue-side and red-side of the visible spectrum respectively. This independent coating. Detectors also reflect this choice, being optimized separately. We present the most relevant features of the instrument, the optical design as well as the structural and mechanical layout. Each of the two Prime Focus cameras gather light form a very fast, F/1.14 parabolic primary mirror. The field is corrected over roughly half a degree in size, allowing optical performances in terms of 80 percent of Encircled Energy in better than approximately 0.3 inch. Focal length is slightly increased in order to provide a better sampling using 13.5 micrometers pixel size chips. The CCD array is made up with 4 EEV 42-90 chips, per channel, to obtain an equivalent 6000 by 6000 pixels optimizing the AR coating to the U,B,V and V,R,I,Z bands respectively. The array will be read out in 10 seconds using a 1Meegapixel/second controller with four video channels. The cryostat will use a state of the art dewar to reach an holding time of several days using a limited amount of liquid nitrogen. The whole mechanical design has bene modeled using Finite Elements analysis in order to check for mechanical flexures of the mount tube and of the optical components by themselves. A brief overview of the informative facilities to be provided with the instrument and of a few science case studies that can be attacked by this instrument are also given.
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