scholarly journals The Pristine survey XI: the FORS2 sample

2020 ◽  
Vol 493 (4) ◽  
pp. 4677-4691 ◽  
Author(s):  
E Caffau ◽  
P Bonifacio ◽  
L Sbordone ◽  
A M Matas Pinto ◽  
P François ◽  
...  
Keyword(s):  
Narrow Band ◽  
Broad Band ◽  
Wide Band ◽  
Big Bang ◽  
Wide Field ◽  
Low Resolution ◽  
Giant Stars ◽  
Carbon Abundance ◽  
The Big Bang

Abstract Extremely metal-poor (EMP) stars are old objects that mostly formed very early after the big bang. They are rare and, to select them, we have to rely on low-resolution spectroscopic or photometric surveys; specifically the combination of narrow- and broad-band photometry provides a powerful and time efficient way to select MP stars. The Pristine photometric survey is using the Canada–France–Hawaii Telescope MegaCam wide-field imager to obtain narrow-band photometry by utilizing a filter centred at 395.2 nm on the Ca ii-H and -K lines. Gaia DR 2 is providing us the wide-band photometry as well as parallaxes. Follow-up observations of MP candidates allowed us to improve our photometric calibrations. In this paper of the series we analyse MP stars observed with FORS2 at VLT. We demonstrate the Pristine calibration adopted in this work to be able to provide metallicities accurate to ±0.3 dex for MP giant stars with good parallaxes, while it performs poorly for dwarf and turn-off stars, whatever the accuracy on the parallaxes. We find some MP and very MP stars that are not enhanced in α elements. Such stars have already been found in several other searches, and a higher resolution follow-up of our sample would be useful to put our findings on a firmer ground. This sample of stars analysed has a low fraction of carbon-enhanced MP stars, regardless of the definition adopted. This deficiency could indicate a small sensitivity of the Pristine filter to carbon abundance, issue to be addressed in the future.

scholarly journals JPCAM: A 1.2 GPIXEL CAMERA FOR THE J-PAS SURVEY

2014 ◽  
Vol 03 (01) ◽  
pp. 1350010 ◽  
Author(s):  
K. TAYLOR ◽  
A. MARÍN-FRANCH ◽  
R. LAPORTE ◽  
F. G. SANTORO ◽  
L. MARRARA ◽  
...  
Keyword(s):  
Image Quality ◽  
Narrow Band ◽  
Broad Band ◽  
Red Shift ◽  
Wide Field ◽  
Acoustic Oscillations ◽  
Mechanical Structure ◽  
Science Projects ◽  
Actuator System ◽  
Survey Strategy

JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10 μm-pixel 16-channel detectors, to be deployed on a dedicated 2.55 m wide-field telescope at the OAJ (Observatorio Astrofísico de Javalambre) in Aragon, Spain. The camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band (~ 13.8 nm) filters equi-spaced between 370 and 920 nm plus 3 broad-band filters to achieve unprecedented photometric red-shift accuracies for faint galaxies over ~8000 square degrees of sky. The cryostat, detector mosaic and read electronics, is being supplied by e2v under contract to J-PAS while the mechanical structure, housing the shutter and filter assembly, is being designed and constructed by a Brazilian consortium led by INPE (Instituto Nacional de Pesquisas Espaciais). The cryostat is bridged to the telescope via a hexapod actuator system to maintain image quality across the field. Four sets of 14 filters are placed in the ambient environment, just above the dewar window but directly in line with the detectors, leading to a mosaic having ~ 10 mm gaps between each CCD. The massive 500 mm aperture shutter is expected to be supplied by the Bonn-Shutter UG. We will present an overview of JPCam, from the filter configuration through to the CCD mosaic camera. A brief outline of the main J-PAS science projects will be included.

scholarly journals Tetrachromacy in a butterfly that has eight varieties of spectral receptors

2008 ◽  
Vol 275 (1637) ◽  
pp. 947-954 ◽  
Author(s):  
Hisaharu Koshitaka ◽  
Michiyo Kinoshita ◽  
Misha Vorobyev ◽  
Kentaro Arikawa
Keyword(s):  
Colour Vision ◽  
Narrow Band ◽  
Monochromatic Light ◽  
Broad Band ◽  
Wide Band ◽  
Swallowtail Butterfly ◽  
Discrimination Ability ◽  
Papilio Xuthus ◽  
Wavelength Discrimination

This paper presents the first evidence of tetrachromacy among invertebrates. The Japanese yellow swallowtail butterfly, Papilio xuthus , uses colour vision when foraging. The retina of Papilio is furnished with eight varieties of spectral receptors of six classes that are the ultraviolet (UV), violet, blue (narrow-band and wide-band), green (single-peaked and double-peaked), red and broad-band classes. We investigated whether all of the spectral receptors are involved in colour vision by measuring the wavelength discrimination ability of foraging Papilio . We trained Papilio to take nectar while seeing a certain monochromatic light. We then let the trained Papilio choose between two lights of different wavelengths and determined the minimum discriminable wavelength difference Δ λ . The Δ λ function of Papilio has three minima at approximately 430, 480 and 560 nm, where the Δ λ values approximately 1 nm. This is the smallest value found for wavelength discrimination so far, including that of humans. The profile of the Δ λ function of Papilio can be best reproduced by postulating that the UV, blue (narrow-band and wide-band), green (double-peaked) and red classes are involved in foraging. Papilio colour vision is therefore tetrachromatic.

scholarly journals Ultra-Wideband Networking

2021 ◽  
pp. 565-569
Author(s):  
Prachi Kandalkar
Keyword(s):  
Narrow Band ◽  
Broad Band ◽  
Wide Band ◽  
Ultra Wideband ◽  
Ultra Wide Band ◽  
Future Change ◽  
Wireless Applications ◽  
Advantages And Disadvantages ◽  
The World ◽  
Recent Developments

Ultra broad band (UWB) has emerged as a leading technology for potential wireless applications due to recent developments in wideband impulse technology, low power and communication. When opposed to traditional narrow band networks, ultra-wide band (UWB) wireless communications takes a completely different approach to wireless communication. The technology is generating a lot of buzz around the world. This paper outlines the characteristics, its applications, and advantages and disadvantages. It main focuses on the future change of UWB.

scholarly journals Searching for planetary nebulae at the Galactic halo via J-PAS

2015 ◽  
Vol 11 (S317) ◽  
pp. 304-305
Author(s):  
Denise R. Gonçalves ◽  
T. Aparício-Villegas ◽  
S. Akras ◽  
A. Cortesi ◽  
M. Borges-Fernandes ◽  
...  
Keyword(s):  
Galactic Halo ◽  
Narrow Band ◽  
Narrow Band Imaging ◽  
Broad Band ◽  
Planetary Nebulae ◽  
Accelerating Universe ◽  
Wide Field ◽  
The Galaxy ◽  
First Results ◽  
Chemical Conditions

AbstractThe Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow-band imaging, very wide field cosmological survey. It will last 5 years and will observe 8500 sq. deg. of the sky. There will be 54 contiguous narrow-band filters of 145Å FWHM, from 3,500 to 10,000Å. Two broad-band filters will be added at the extremes, UV and IR, plus the 3–g, r, and i– SDSS filters. Thus, J-PAS can be an important tool to search for new planetary nebulae (PNe) at the halo, increasing their numbers, because only 14 of them have been convincingly identified in the literature. Halo PNe are able to reveal precious information for the study of stellar evolution and the early chemical conditions of the Galaxy. The characteristic low continuum and intense emission lines of PNe make them good objects to be searched by J-PAS. Though covering a significantly smaller sky area, data from the ALHAMBRA survey were used to test our J-PAS strategy to search for PNe. Our first results are shown in this contribution.

scholarly journals Unveiling the most luminous Lyman-α emitters in the epoch of reionisation

2019 ◽  
Vol 15 (S352) ◽  
pp. 21-25
Author(s):  
Jorryt Matthee ◽  
David Sobral
Keyword(s):  
Interstellar Medium ◽  
Complex Systems ◽  
Rest Frame ◽  
Big Bang ◽  
Young Stars ◽  
Spatially Resolved ◽  
Luminous Galaxies ◽  
Follow Up Studies ◽  
The Big Bang

AbstractDistant luminous Lyman-α emitters are excellent targets for detailed observations of galaxies in the epoch of reionisation. Spatially resolved observations of these galaxies allow us to simultaneously probe the emission from young stars, partially ionised gas in the interstellar medium and to constrain the properties of the surrounding hydrogen in the circumgalactic medium. We review recent results from (spectroscopic) follow-up studies of the rest-frame UV, Lyman-α and [CII] emission in luminous galaxies observed ∼500 Myr after the Big Bang with ALMA, HST/WFC3 and VLT/X-SHOOTER. These galaxies likely reside in early ionised bubbles and are complex systems, consisting of multiple well separated and resolved components where traces of metals are already present.

scholarly journals Beauty and Astrophysics

2000 ◽  
Vol 17 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Michael S. Bessell
Keyword(s):  
Milky Way ◽  
Galactic Plane ◽  
Narrow Band ◽  
Public Awareness ◽  
Broad Band ◽  
Wide Field ◽  
Single Exposure ◽  
Star Forming ◽  
Star Forming Regions ◽  
Telephoto Lens

AbstractSpectacular colour images have been made by combining CCD images in three different passbands using Adobe Photoshop. These beautiful images highlight a variety of astrophysical phenomena and should be a valuable resource for science education and public awareness of science. The wide field images were obtained at the Siding Spring Observatory (SSO) by mounting a Hasselblad or Nikkor telephoto lens in front of a 2K × 2K CCD. Options of more than 30 degrees or 6 degrees square coverage are produced in a single exposure in this way. Narrow band or broad band filters were placed between lens and CCD enabling deep, linear images in a variety of passbands to be obtained. We have mapped the LMC and SMC and are mapping the Galactic Plane for comparison with the Molonglo Radio Survey. Higher resolution images have also been made with the 40 inch telescope of galaxies and star forming regions in the Milky Way.

scholarly journals Impact of a caries preventive intervention in remote Indigenous Australian children

2019 ◽  
Author(s):  
Ratilal Lalloo ◽  
TADAKAMADLA SANTOSH KUMAR ◽  
Jeroen Kroon ◽  
Lisa M Jamieson ◽  
Newell Johnson
Keyword(s):  
Comparison Group ◽  
Preventive Intervention ◽  
Big Bang ◽  
Carious Lesions ◽  
Caries Increment ◽  
Indigenous Children ◽  
Preventive Fraction ◽  
The Big Bang ◽  
Experimental Group

IMPORTANCE: The burden of dental caries in remote Indigenous communities in Australia is unacceptably high. OBJECTIVES: We tested the impact of an annual caries preventive intervention, delivered by a fly-in/fly-out professional team, on Indigenous children residing in a remote Australian community, involving selective fissure sealants, topical povidone iodine and fluoride varnish application. The outcome was caries increment at 12- and 24-month follow-up. DESIGN, SETTING, PARTICIPANTS: Around 600 Indigenous children aged 5 to 17 years were invited to participate at baseline, of which 408 had caregiver consent provided. Of these, 196 consented to both the study and the treatment arm and comprised the experimental group. Two hundred and twelve consented to the epidemiological examination only, and constituted the comparison group. INTERVENTION: The Big Bang intervention, which occurred annually, comprised placement of fissure sealants, and application of povidone-iodine and fluoride varnish, following completion of each childs dental treatment plan. Standard diet and oral hygiene advice was provided. MAIN OUTCOMES AND MEASURES: Caries increment (number of tooth surfaces with new dental caries) in both primary and permanent dentitions at 12- and 24-month follow-up. RESULTS: At 12-month follow-up, children in the experimental group had, on average, 5.05 (5.47) new carious lesions compared to 7.49 (6.94) in the comparison group (p=0.001). The preventive fraction was 33%. At 24-month follow-up, children in the experimental group had, on average, 6.47 (6.07) new carious lesions compared to 8.43 (5.83) in the comparison group (p=0.002). The preventive fraction was 23%. CONCLUSIONS AND RELEVANCE: Indigenous children exposed to the Big Bang caries intervention had significantly less increment in dental disease than those not exposed to the intervention. Benefits were demonstrated at both 12- and 24-month follow-ups, suggesting that the intervention is likely to be sustained if delivered across a childs life. The cost-effectiveness of this approach is being evaluated.

scholarly journals Hα imaging for BeXRBs in the Small Magellanic Cloud

2016 ◽  
Vol 12 (S329) ◽  
pp. 373-375 ◽  
Author(s):  
G. Maravelias ◽  
A. Zezas ◽  
V. Antoniou ◽  
D. Hatzidimitriou ◽  
F. Haberl
Keyword(s):  
Narrow Band ◽  
Formation Rate ◽  
Broad Band ◽  
Magellanic Cloud ◽  
High Mass ◽  
Wide Field ◽  
Small Magellanic Cloud ◽  
X Ray ◽  
Hα Emission ◽  
X Ray Binaries

AbstractThe Small Magellanic Cloud (SMC) hosts a large number of high-mass X-ray binaries, and in particular of Be/X-ray Binaries (BeXRBs; neutron stars orbiting OBe-type stars), offering a unique laboratory to address the effect of metalicity. One key property of their optical companion is Hα in emission, which makes them bright sources when observed through a narrow-band Hα filter. We performed a survey of the SMC Bar and Wing regions using wide-field cameras (WFI@MPG/ESO and MOSAIC@CTIO/Blanco) in order to identify the counterparts of the sources detected in our XMM-Newton survey of the same area. We obtained broad-band R and narrow-band Hα photometry, and identified ~10000 Hα emission sources down to a sensitivity limit of 18.7 mag (equivalent to ~B8 type Main Sequence stars). We find the fraction of OBe/OB stars to be 13% down to this limit, and by investigating this fraction as a function of the brightness of the stars we deduce that Hα excess peaks at the O9-B2 spectral range. Using the most up-to-date numbers of SMC BeXRBs we find their fraction over their parent population to be ~0.002 − 0.025 BeXRBs/OBe, a direct measurement of their formation rate.

A view of the universe before the big bang

2006 ◽  
Vol 190 ◽  
pp. 15-15
Author(s):  
D CASTELVECCHI
Keyword(s):  
Big Bang ◽  
The Big Bang ◽  
The Universe
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