In the phenomenon of gravitational lensing, predicted by Einstein's General Theory of Relativity, the mass of a galaxy acts on the light of a more distant object, as if it were a huge lens, producing a distorted image with the form of a so-called Einstein ring or multiple images and a magnification of the total flux, allowing to see details which would otherwise be too faint to detect. GTC/OSIRIS spectroscopic observations allowed to discover one of the brightest galaxies in the early Universe, BG1429+1202, located at a redshift of 2.82 (we see it as it was some 2,300 million years after the Big Bang). BG1429+1202 is a Lyman-Alpha Emitting galaxy (LAE) gravitationally lensed by a massive Early Type galaxy close to the line of sight at a redshift of 0.55. Although typical LAEs are faint and not very luminous, BG1429+1202 is not only apparently bright but also intrinsically very luminous after accounting for the lensing magnification, showing indications of massive star formation. This galaxy-scale strong gravitational system was found in the BELLS GALLERY project that analysed around a million and a half spectra of galaxies obtained with the Sloan Telescope, at the Apache Point Observatory in New Mexico (USA), by the BOSS survey, part of the Sloan Digital Sky Survey III.
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Dark matter is an invisible substance that makes up more than eighty percent of the matter content of the universe. We know of its existence due to its gravitational influence, being a key ingredient to understand everything from the large-scale evolution of the universe to the formation of galaxies like the Milky Way, of which we are part of . However, very little is known about its nature, which constitutes one of the greatest unsolved problems in contemporary physics. The fuzzy dark matter model has recently been studied as a promising candidate. In this model , it is postulated that dark
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The cosmic evolution of the barred galaxy population provides key information about the secular evolution of galaxies and the settling of rotationally dominated discs. We study the bar fraction in the SMACSJ0723.37323 (SMACS0723) cluster of galaxies at z = 0.39 using the Early Release Observations obtained with the NIRCam instrument mounted on the JWST telescope. We visually inspected all cluster member galaxies using the images from the NIRCam F200W filter. We classified the galaxies into ellipticals and discs and determine the presence of a bar. The cluster member selection was based on a
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Stellar ages are key to several fields of astrophysics such as exoplanet research, galactic-archeology, and of course stellar physics. Obtaining the ages of stars is however not straightforward and requires stellar modeling. The most widely used technique only requires stellar colors or temperature and surface gravity, but the uncertainties are quite large. This technique is most efficient for stars belonging to clusters, as they were born from the same molecular cloud and share the same ages. In the last decades, based on the study of stellar acoustic waves, asteroseismology became the most
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