GEP I: A globular cluster in the center of the dwarf spheroidal galaxy Andromeda XXV?

2019 ◽  
Vol 14 (S351) ◽  
pp. 64-67
Author(s):  
Felice Cusano ◽  
Alessia Garofalo ◽  
Gisella Clementini
Keyword(s):  
Globular Clusters ◽  
Linear Extension ◽  
Heliocentric Distance ◽  
Stellar Population ◽  
Variable Stars ◽  
High Resolution Imaging ◽  
Real Nature ◽  
Real Concentration ◽  
Resolution Imaging ◽  
Imaging And Spectroscopy

AbstractLooking for variable stars in the M31 dwarf spheroidal satellite Andromeda XXV (And XXV), which we have observed with the LBC at the LBT, we serendipitously discovered a clustering of stars (Gep I) of 12 arcsec in diameter, near the center of And XXV. This is one of the very few clusters known to be associated with a dwarf spheroidal galaxy. The half light radius (rh) of Gep I at the distance of And XXV corresponds to 25 pc in linear extension. Radius and absolute V (MV∼ −4.9 mag) magnitude place Gep I in the region of the MV-rh plane that seems to be forbidden to ordinary globular clusters (GCs). The seeing-limited resolution of our photometry could resolve only a few bright stars in Gep I. The CMD of these sources is compatible with an old stellar population placed at a heliocentric distance of ∼750–800 kpc, thus confirming a real concentration of old stars. The ground-based CMD of Gep I is severely incomplete. Future high resolution imaging and spectroscopy of the brightest stars will permit to disentangle the puzzle on the real nature of Gep I.

High-Resolution Imaging and Spectroscopy of Multipolar Plasmonic Resonances in Aluminum Nanoantennas

Nano Letters ◽  
2014 ◽  
Vol 14 (10) ◽  
pp. 5517-5523 ◽  
Author(s):  
Jérôme Martin ◽  
Mathieu Kociak ◽  
Zackaria Mahfoud ◽  
Julien Proust ◽  
Davy Gérard ◽  
...  
Keyword(s):  
High Resolution ◽  
High Resolution Imaging ◽  
Resolution Imaging ◽  
Imaging And Spectroscopy

scholarly journals Star-forming, rotating spheroidal galaxies in the GAMA and SAMI surveys

2019 ◽  
Vol 489 (2) ◽  
pp. 2830-2843 ◽  
Author(s):  
Amanda J Moffett ◽  
Steven Phillipps ◽  
Aaron S G Robotham ◽  
Simon P Driver ◽  
Malcolm N Bremer ◽  
...  
Keyword(s):  
Stellar Population ◽  
Elliptical Galaxies ◽  
High Resolution Imaging ◽  
Detailed Structure ◽  
Star Forming ◽  
The Galaxy ◽  
Low Mass ◽  
Resolution Imaging ◽  
Mass Assembly ◽  
Integral Field

ABSTRACT The Galaxy And Mass Assembly (GAMA) survey has morphologically identified a class of ‘Little Blue Spheroid’ (LBS) galaxies whose relationship to other classes of galaxies we now examine in detail. Considering a sample of 868 LBSs, we find that such galaxies display similar but not identical colours, specific star formation rates, stellar population ages, mass-to-light ratios, and metallicities to Sd-Irr galaxies. We also find that LBSs typically occupy environments of even lower density than those of Sd-Irr galaxies, where ∼65 per cent of LBS galaxies live in isolation. Using deep, high-resolution imaging from VST KiDS and the new Bayesian, 2D galaxy profile modelling code profit, we further examine the detailed structure of LBSs and find that their Sérsic indices, sizes, and axial ratios are compatible with those of low-mass elliptical galaxies. We then examine SAMI Galaxy survey integral field emission line kinematics for a subset of 62 LBSs and find that the majority (42) of these galaxies display ordered rotation with the remainder displaying disturbed/non-ordered dynamics. Finally, we consider potential evolutionary scenarios for a population with this unusual combination of properties, concluding that LBSs are likely formed by a mixture of merger and accretion processes still recently active in low-redshift dwarf populations. We also infer that if LBS-like galaxies were subjected to quenching in a rich environment, they would plausibly resemble cluster dwarf ellipticals.

scholarly journals A New Type of Atmospheric Dispersion Corrector Suitable for Wide-Field High-Resolution Imaging and Spectroscopy on Large Telescopes

2021 ◽  
Vol 11 (14) ◽  
pp. 6261
Author(s):  
Andrew Rakich
Keyword(s):  
High Resolution ◽  
Atmospheric Dispersion ◽  
Wide Field ◽  
High Resolution Imaging ◽  
Dispersion Correction ◽  
Atmospheric Effect ◽  
New Type ◽  
Resolution Imaging ◽  
Imaging And Spectroscopy ◽  
Large Telescopes

Atmospheric dispersion produces spectral elongation in images formed by land-based astronomical telescopes, and this elongation increases as the telescope points away from the zenith. Atmospheric Dispersion Correctors (ADCs) produce compensating dispersion that can be adjusted to best cancel out the atmospheric effect. These correctors are generally of two basic types: Rotating Atmospheric Dispersion Correctors (R-ADCs), and Linear Atmospheric Dispersion Correctors (L-ADCs). Lately, a third type, the “Compensating Lateral ADC” (CL-ADC) has been proposed. None of these design approaches allow for large corrector systems (with elements greater than 1 m in diameter), in which the secondary spectrum is corrected to small residuals, of the order of tens’ of milliarcseconds. This paper describes a new type of large corrector (>1 m diameter elements), which can achieve the correction of the secondary spectrum to the order of 10 milliarcseconds. This correction is achieved by combining the R-ADC and CL-ADC approaches to dispersion correction. Only glass types readily available in metre diameters are required.

Fabrication of CdZnTe Strip Detectors for Large Area Arrays

1997 ◽  
Vol 487 ◽  
Author(s):  
C. M. Stahle ◽  
Z. Q. Shi ◽  
K. Hu ◽  
S. D. Barthelmy ◽  
S. J. Snodgrass ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Resolution Imaging ◽  
Two Dimensional ◽  
Large Area ◽  
Array Design ◽  
Nuclear Medical Imaging ◽  
Strip Detectors ◽  
Resolution Imaging ◽  
Strip Detector ◽  
Imaging And Spectroscopy

AbstractA CdZnTe strip detector large area array (∼ 60 cm2 with 36 detectors) with capabilities for high resolution imaging and spectroscopy has been built as a prototype for a space flight gamma ray burst instrument. The detector array also has applications in nuclear medical imaging. Two dimensional orthogonal strip detectors with 100 μm pitch have been fabricated and tested. Details for the array design, fabrication and evaluation of the detectors will be presented.

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