New Findings By Hubble-VLT Data Could be The Key Link to The Missing Piece of Puzzle of Current Dark Matter Theory
New Findings By Hubble-VLT Data Could be The Key Link to The Missing Piece of Puzzle of Current Dark Matter Theory
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| Image Credit: NASA, ESA, G. Caminha (University of Groningen), M. Meneghetti (Observatory of Astrophysics and Space Science of Bologna), P. Natarajan (Yale University), and the CLASH team |
What is dark matter?
Dark matter is the only thing which binds all the stars, gases and dust in a galaxy together. Without presence of dark matter, it is impossible to bound these objects, which are moving and rotation in such a high speed, to form a galaxy are rotating at such a high speed. The gravity produced by the visible matter of the galaxy is not enough to hold these components together to form a galaxy. Same is true for Galaxy clusters, where large number of individual galaxies are bound together.
Dark matter is invisible because it does not interact with electromagnetic force. Dark matters do not absorb, reflect or emit of e.m. radiation of any frequency. This is why its called dark matter. E.M. radiation whether it is gamma, radio wave or infrared, is most important probing tool for astrophysicists. Only method to probe the presence of dark matter is its gravitational effect on visible matter.
Mapping of Dark Matter in Three Galaxy Clusters
The only way scientists can map the distribution of dark matter is by measuring the enhanced gravitational lensing effect on light coming from a distant galaxy in background. The presence of dark matter in the galaxy cluster highly enhances the gravitational lensing effect. Gravitational lensing effect could wrap light coming from distant galactic source causing the galaxy to appear distorted and sometimes multiple images of same galaxy. The higher the dark matter concentration more enhanced the gravitational lensing effect.
Scientists were involved in studying gravitational lensing effects in three galaxy clusters, namely- MACS J1206.2-0847, MACS J0416.1-2403 and Abell S1063. By coupling the Hubble’s crisp images, taken by its Wide Field Camera 3 and Advanced Camera for Surveys, with the spectra from European Southern Observatory’s VLT, scientists analysed the lensing effect in the three galaxy clusters and were able to calculate the amount of dark matter present and a detailed map about the distribution of dark matter was constructed.
The Findings
Scientists were surprised when they found out an unexpected number of smaller scale arcs and distorted image nested near the core of each cluster apart from the dramatic arcs and elongated features of distant galaxies which was normally expected to be produced by gravitational lensing of the cluster galaxies.
The reason behind the unexpected number of nested arcs could be due to high concentration of high concentration of matter (dark matter) near the core of the clusters.
No computer simulated cluster models with similar masses and roughly the same cluster- background galaxy distances could show the presence of same amount of dark matter concentration as obtained from Hubble-VLT data.
This discrepancy in dark matter concentration as obtained by the computer simulations, indicates that current Dark Matter theory clearly missing some important features about dark matter.
References--
1)CERN
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