The performance of the blue prime focus large binocular camera at the large binocular telescope

Giallongo, E.; Ragazzoni, Roberto; Grazian, A.; Baruffolo, A.; Beccari, G.; Santis, C. De; Diolaiti, Emiliano; Paola, Andrea; Farinato, Jacopo; Fontana, A.; Gallozzi, S.; Gasparo, F.; Gentile, G.; Green, R.; Hill, John M.; Kuhn, O.; Pasian, F.; Pedichini, Fernando; Radovich, M.; Salinari, Piero; Smareglia, R.; Speziali, R.; Testa, V.; Thompson, D. J.; Vernet, Elise; Wagner, R. M.

doi:10.1051/0004-6361:20078402

Cited by 113 publications

(124 citation statements)

References 20 publications

(23 reference statements)

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“…In addition, a mask with an exposure map was used to mask low exposure time regions that were the result of the dithering technique. A detailed description of the reduction procedure can be found in Giallongo et al (2008). Finally, visual inspection was needed to mask spikes caused by to saturation, bright star haloes (due to reflections within the cameras), and artifacts.…”

Section: Observationsmentioning

confidence: 99%

“…In this work, we study the fields around four of the most distant QSOs known to date using wide-area, deep images in the r-, i-and z-bands, obtained with the Large Binocular Cameras (LBC; Giallongo et al 2008) at the Large Binocular Telescope (LBT 1 ) on Mount Graham in Arizona. LBC is caracterized by a unique etendue, the product between collecting area and field of 1 The LBT is an international collaboration among institutions in the United States, Italy, and Germany.…”

Section: Introductionmentioning

confidence: 99%

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Primordial environment of super massive black holes: large-scale galaxy overdensities aroundz ~ 6 quasars with LBT

Morselli

Mignoli

Gilli

et al. 2014

A&A

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Context. In the current model of structure formation, bright quasars (QSOs) at z ∼ 6 are assumed to be hosted by the most massive dark matter halos that collapsed at that time. The large-scale structures in which these halos are embedded may extend up to 10 physical Mpc, and probably can be traced by overdensities of star-forming galaxies. To date, the search for these overdensities has been limited to scales of 1-2 physical Mpc around the QSO and did not produce coherent results. Aims. We aim at studying the environment of z ∼ 6 QSOs and verify whether they are associated with large-scale overdensities of galaxies selected at the same redshift as i-band dropouts. Methods. With the wide-field (∼23 × 25 ) Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT), we obtained deep r-, i-and z-band imaging of the fields around four high-z QSOs, namely SDSS J1030+0524 (z = 6.28), SDSS J1148+5251 (z = 6.41), SDSS J1048+4637 (z = 6.20), and SDSS J1411+1217 (z = 5.95). Our photometric catalogs are based on source detection in the z-band image (5σ) and contain from ∼2.3 × 10 4 to ∼2.9 × 10 4 objects, down to a 50% completeness limit of z = 25.0-25.2 AB mag. We adopted color-color selections within the i − z vs. r − z plane to identify samples of i-band dropouts at the QSO redshift and measured their relative abundance and spatial distribution in the four LBC fields, each covering ∼8 × 8 physical Mpc at z ∼ 6. The same selection criteria were then applied to z-band-selected sources in the ∼1 deg 2 wide-and-deep Subaru-XMM Newton Deep Survey (SXDS) to derive the expected number of dropouts over a blank LBC-sized field (∼0.14 deg 2 after removing masked regions). Results. The four observed QSO fields host more candidates than expected in a blank field. By defining objects with z AB < 25 and i − z > 1.4 that are undetected in the r-band as i-band dropouts, we found 16, 10, 9, and 12 dropouts in SDSS J1030+0524, SDSS J1148+5251, SDSS J1048+4637, and SDSS J1411+1217, respectively, whereas only 4.3 such objects are expected over a 0.14 deg 2 blank field. This corresponds to overdensity significances of 3.3, 1.9, 1.7, and 2.5σ, respectively, after accounting for cosmic variance and for the contamination by bluer objects in our dropout samples produced by photometric errors. By considering the total number of dropouts in the four LBC fields and comparing it with what is expected in four blank fields of 0.14 deg 2 each, we find that high-z QSOs reside in overdense environments at the 3.7σ level. This is the first direct and unambiguous measurement of the large-scale structures around z ∼ 6 QSOs.

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Section: Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Primordial environment of super massive black holes: large-scale galaxy overdensities aroundz ~ 6 quasars with LBT

Morselli

Mignoli

Gilli

et al. 2014

A&A

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“…For each star, the luminosity and effective temperature were derived according to evolutionary tracks by the BaSTI database, then magnitudes in the photometric bands of the LBT/LBC channels (both red and blue) were computed using colour-temperature relations derived from the stellar atmospheres by Castelli & Kurucz (2003, and references therein). The LBC-filter response curves were taken from Giallongo et al (2008) and Speziali et al (2008). We explored different assumptions on stellar population parameters, such as total mass, age, metallicity, and different parameterizations of the HB star distribution (the Reimers mass-loss parameter η R , its dispersion σ R , etc.).…”

Section: Colour-magnitude Diagramsmentioning

confidence: 99%

A bag of tricks: Using proper motions of Galactic stars to identify the Hercules ultra-faint dwarf galaxy members

Fabrizio

Raimondo

Brocato

et al. 2014

A&A

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Context. Discovered in the last decade as overdensities of resolved stars, the ultra-faint dwarfs (UFDs) are among the least luminous, most dark-matter dominated, and most metal-poor galaxies known today. They appear as sparse, loose objects with high mass-to-light ratios. Hercules is the prototype of the UFD galaxies. To date, there are still no firm constraints on its total luminosity due to the difficulty of disentangling Hercules bona-fide stars from the severe Galactic field contamination. Aims. To better constrain Hercules properties, we aim at removing foreground and background contaminants in the galaxy field using the proper motions of the Milky Way stars and the colour-colour diagram. Methods. We have obtained images of Hercules in the r Sloan , B Bessel and U spec bands with the Large Binocular Telescope (LBT) and LBC-BIN mode capabilities. The r Sloan new dataset combined with data from the LBT archive span a time baseline of about 5 yr, allowing us to measure proper motions of stars in the Hercules direction for the first time. The U spec data along with existing LBT photometry allowed us to use colour-colour diagram to further remove the field contamination.Results. Thanks to a highly-accurate procedure to derive the r Sloan -filter geometric distortion solution for the LBC-red, we were able to measure stellar relative proper motions to a precision of better than 5 mas yr −1 down to r Sloan 22 mag and disentangle a significant fraction (>90%) of Milky Way contaminants. We ended up with a sample of 528 sources distributed over a large portion of the galaxy body (∼0.12 deg 2 ). Of these sources, 171 turned out to be background galaxies and additional foreground stars from the analysis of the U spec − B Bessel vs. B Bessel − r Sloan colour-colour diagram. This leaves us with a sample of 357 likely members of the Hercules UFD. We compared the cleaned colour-magnitude diagram (CMD) with evolutionary models and synthetic CMDs, confirming the presence in Hercules of an old population (t = 12 ± 2 Gyr) with wide spread metallicity (−3.3 < [Fe/H] < −1.8). Conclusions. Our procedure to estimate star proper motions proved to be a very effective way to identify likely members for stellar systems as far as 130 kpc. The present selection, based on both proper motions and colour-colour diagram, provides a robust identification of Hercules members and a new target list for more spectroscopic investigations.

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“…Deep g and r photometry was acquired on the night of December 2, 2008, at LBT, using the blue channel of the Large Binocular Camera (Giallongo et al 2008). LBC optics feed a mosaic of four 4608 px × 2048 px CCDs, with a pixel scale of 0.225 arcsec px −1 .…”

Section: Lbt Observations and Data Reductionmentioning

confidence: 99%

“…Chips 1, 2, and 3 are flanking one another, being adjacent along their long sides; Chip 4 is placed perpendicular to this array, with its long side adjacent to the short sides of the other chips (see Fig. 4 of Giallongo et al 2008). During our observations the pointing was chosen to place VV124 at the center of Chip 2, with the long side nearly aligned with the major axis of the galaxy (see Fig.…”

Section: Lbt Observations and Data Reductionmentioning

confidence: 99%

An optical and H i study of the dwarf Local Group galaxy VV124 = UGC4879

Bellazzini

Beccari

Oosterloo

et al. 2011

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We present a detailed study of the dwarf galaxy VV124 (UGC4879), recently recognized as a remarkably isolated member of the Local Group. We have obtained deep (r 26.5) wide-field (23 × 23 ) g,r photometry of individual stars with the LBC camera at the Large Binocular Telescope under sub-arcsec seeing conditions. The color-magnitude diagram suggests that the stellar content of the galaxy is dominated by an old, metal-poor population, with a significant metallicity spread. A very clean detection of the RGB tip allows us to derive an accurate distance of D = 1.3 ± 0.1 Mpc. Combining surface photometry with star counts, we are able to trace the surface brightness profile of VV124 out to ∼5 1.9 kpc radius (where μ r 30 mag/arcsec 2 ), showing that it is much more extended than previously believed. Moreover, the surface density map reveals the presence of two symmetric flattened wings emanating from the central elongated spheroid and aligned with its major axis, resembling a stellar disk seen nearly edge-on. We also present H i observations obtained with the Westerbork Synthesis Radio Telescope (WSRT), the first ever of this object. A total amount of 10 6 M of H i gas is detected in VV124. Compared to the total luminosity, this gives a value of M HI /L V = 0.11, which is particularly low for isolated Local Group dwarfs. The spatial distribution of the gas does not correlate with the observed stellar wings. The systemic velocity of the H i in the region superposed to the stellar main body of the galaxy is V h = −25 km s −1 . The velocity field shows substructures typical of galaxies of this size but no sign of rotation. The H i spectra indicates the presence of a two-phase interstellar medium, again typical of many dwarf galaxies.

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The performance of the blue prime focus large binocular camera at the large binocular telescope

Cited by 113 publications

References 20 publications

Primordial environment of super massive black holes: large-scale galaxy overdensities aroundz ~ 6 quasars with LBT

Primordial environment of super massive black holes: large-scale galaxy overdensities aroundz ~ 6 quasars with LBT

A bag of tricks: Using proper motions of Galactic stars to identify the Hercules ultra-faint dwarf galaxy members

An optical and H i study of the dwarf Local Group galaxy VV124 = UGC4879

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