Photometry of distant clusters of galaxies : evolutionary features in the cluster 2158+0351 (z = 0.45)

Results of detailed three-colour photometry of the distant cluster 21 58 + 035 (z = 0.445) are presented. A photometric catalogue has been produced using the INVENTORY package, for which we give an estimate of completeness and photometry errors. In total we measured Gunn g, r, i magnitudes for 294 objects, down to r = 23.5, with a typical error of 0.1 mag. On the basis of a statistical analysis, about 60 per cent of these are suggested to be cluster members. Luminosity functions ar shown along with colour-magnitude and two-colour diagrams. We find that the bright- cluster galaxy population is dominated by ellipticals, while a population of spirals becomes relevant at the faint luminosities. Such an overabundance of faint spiral leads us to calculate a high fraction of blue objects, according to the Butcher-Oemler effect. We find f_B_ = 0.3 +/- 0.13. We evidence possible photometric effects on magnitudes and colours due to galactic evolution. In particular, elliptical galaxies in the cluster are recognized to be bluer than present-day descendants, and the first-rank galaxy is intrinsically brighter by about 0.8 mag. An independent estimate of the redshift of the cluster, through photometric properties of its galaxy population, - attempted, deriving z = 0.44 +/- 0.05. This is obtained taking into account appropriate evolutionary k-corrections from population-synthesis models. The importance of such a correction when studying high redshift (young) galaxies is stressed

Galaxy Colors in Distant Clusters as a Test for the World Model

The operational advantage of using colors of galaxies rather than magnitudes is that they are much less sensitive to deceleration parameter-dependent aperture corrections in photometry; in addition, their estimate is not strongly influenced by distance (as is the case for apparent magnitudes). A study is presently conducted of the colors of elliptical galaxies in nine distant clusters, with reference to theoretical models for evolutionary population synthesis. The admissible ranges of the relevant cosmological parameters are inferred

The very red halo of the cD galaxy in A 3284

We present deep CCD surface photometry in the Gunn g, r, i system and spectroscopy of the cD galaxy at the centre of the cluster A 3284 at z=0.15. The brightness profile of the galaxy has been tracked up to 40 arcsec (142kpc) from the centre, and down to 26 mag/arcsec^+2^. The core and halo components in the galaxy have been singled out deriving geometrical parameters of the fitting isophotes as well as magnitudes and colours. The spectral properties of the galaxy core indicate a stellar population super metal-rich with [Fe/H]=+0.5. The cD halo is clearly dominant at 45kpc from the galactic centre and has exceedingly red colours (g-r=1.03, g-i=1.82), about 0.7mag redder than the core g-i. A match with the models for evolutionary population synthesis by Buzzoni (1989) shows that the halo is consistent with a population of unevolved M-dwarf stars lower than 0.7 Msun_. The M/L ratio in B for the halo is estimated to range between 50 and 200 implying a total mass for the cD galaxy of 1.6-3.1x10^13^Msun_ and a total B luminosity of 6.0x10^11^Lsun_

The HARPS-N archive through a Cassandra, NoSQL database suite?

The TNG-INAF is developing the science archive for the WEAVE instrument. The underlying architecture of the archive is based on a non relational database, more precisely, on Apache Cassandra cluster, which uses a NoSQL technology. In order to test and validate the use of this architecture, we created a local archive which we populated with all the HARPSN spectra collected at the TNG since the instrument's start of operations in mid-2012, as well as developed tools for the analysis of this data set. The HARPS-N data set is two orders of magnitude smaller than WEAVE, but we want to demonstrate the ability to walk through a complete data set and produce scientific output, as valuable as that produced by an ordinary pipeline, though without accessing directly the FITS files. The analytics is done by Apache Solr and Spark and on a relational PostgreSQL database. As an example, we produce observables like metallicity indexes for the targets in the archive and compare the results with the ones coming from the HARPS-N regular data reduction software. The aim of this experiment is to explore the viability of a high availability cluster and distributed NoSQL database as a platform for complex scientific analytics on a large data set, which will then be ported to the WEAVE Archive System (WAS) which we are developing for the WEAVE multi object, fiber spectrograph

Multicolor photometry of clusters of galaxies: A3284, A3305, A1942

We present complete multicolor photometry in the Gunn system for the three clusters of galaxies A3284, A3305 and A1942 at redshift z~0.2. INVENTORY magnitudes and colours have been obtained for over 1,000 objects in the three fields down to g=24, and with a good completeness level in the detections (85% or better) about one magnitude brighter. By fitting with King profiles the r counts we derived the total number of galaxies and the core radius down to the r magnitude limit in each cluster. These are N_TOT_=146 galaxies and R_c_=0.24 Mpc for A3284, N_TOT_=129 and R_c_=0.20 Mpc for A3305, N_TOT_=130 and R_c_=0.24 Mpc for A1942. The observed mean redshift of the clusters is z=0.150+/-0.001 for A3284, z=0.157+/-0.001 for A3305, and z=0.226+/-0.001 for A1942. The c-m diagrams and the g-i colour distribution as well as the two-colour diagrams are used to single out early-type galaxies and spirals on the basis of their different photometric properties. This approach aimed at a self-consistent classification of galaxies on the basis of photometric indicators will be further developed for a systematic study of the galaxy population in distant clusters

Celebrating 20 years of scientific and technical results with the INAF-TNG Telescope

June 9th, 2018 marks the 20th anniversary of the first light of the INAF-Telescopio Nazionale Galileo. This paper is a resume of the main scientific and technical results obtained with the TNG, together with the history of the telescope, the instruments and the people who allowed for several successes and many lessons learned. We will point out what made the TNG a telescope which still can make competitive research in the large and extremely large size telescopes era

The GAPS Project: First Results

The GAPS programme is an Italian project aiming to search and characterize extra-solar planetary systems around stars with different characteristics (mass, metallicity, environment). GAPS was born in 2012, when single research groups joined in order to propose a long-term multi-purpose observing program for the exploitation of the extraordinary performances of the HARPS-N spectrograph, mounted at the Telescopio Nazionale Galileo. Now this group is a concerted community in which wide range of expertise and capabilities are shared in order to reach a more important role in the wider international context. We present the results achieved up to now from the GAPS radial velocity survey: they were obtained in both the two main objectives of the project, the planet detection and the characterization of already known exoplanetary systems. With GAPS we detected, for instance, the first confirmed binary system in which both components host planets (Desidera et al. 2014), the first planetary system around a star in an open cluster (Malavolta et al. 2016), a system of Super-Earths orbiting an M-dwarf star (Affer et al. 2016)

Global Architecture of Planetary Systems (GAPS), a project for the whole Italian Community

The GAPS project is running since 2012 with the goal to optimize the science return of the HARPS-N instrument mounted at Telescopio Nazionale Galileo. A large number of astronomers is working together to allow the Italian community to gain an international position adequate to the HARPS-N capabilities in the exoplanetary researches. Relevant scientific results are being obtained on both the main guidelines of the collaboration, i.e., the discovery surveys and the characterization studies. The planetary system discovered around the southern component of the binary XO-2 and its characterization together with that of the system orbiting the northern component are a good example of the completeness of the topics matched by the GAPS project. The dynamics of some planetary systems are investigated by studying the Rossiter-McLaughlin effect, while host stars are characterized by means of asteroseismology and star-planet interaction

BATMAN: MOS Spectroscopy on Demand

Multi-Object Spectrographs (MOS) are the major instruments for studying primary galaxies and remote and faint objects. Current object selection systems are limited and/or difficult to implement in next generation MOS for space and ground-based telescopes. A promising solution is the use of MOEMS devices such as micromirror arrays, which allow the remote control of the multi-slit configuration in real time. TNG is hosting a novelty project for real-time, on-demand MOS masks based on MOEMS programmable slits. We are developing a 2048×1080 Digital-Micromirror-Device-based (DMD) MOS instrument to be mounted on the Galileo telescope, called BATMAN. It is a two-arm instrument designed for providing in parallel imaging and spectroscopic capabilities. With a field of view of 6.8×3.6 arcmin and a plate scale of 0.2 arcsec per micromirror, this astronomical setup can be used to investigate the formation and evolution of galaxies. The wavelength range is in the visible and the spectral resolution is R=560 for a 1 arcsec object, and the two arms will have 2k × 4k CCD detectors. ROBIN, a BATMAN demonstrator, has been designed, realized and integrated. We plan to have BATMAN first light by mid-2016

MISTRAL and its KIDs

The MIllimetric Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs, MISTRAL, is a cryogenic W-band (77–103 GH) LEKID camera which will be integrated at the Gregorian focus of the 64 m aperture Sardinia Radio Telescope, in Italy, in Autumn 2022. This instrument, thanks to its high angular resolution (∼13arcsec) and the wide instantaneous field of view (∼4arcmin), will allow continuum surveys of the mm-wave sky with a variety of scientific targets, spanning from extragalactic astrophysics to solar system science. In this contribution, we will describe the design of the MISTRAL camera, with a particular focus on the optimisation and test of a prototype of the focal plane