MOND and Dragon Kick galaxies.

DragonKick_MONDMOND (MOdified Newtonian Dynamics) models are popular among some scientist because they avoid one of the biggest problems in cosmology, dark matter. This misterious substance remains undetected although there is evidence from several observations that it must exist and in vast quantities. MOND models are able to explain some of these observations by modifying the laws of gravity. In particular, at cosmic distances MOND models propose that the gravitational acceleration does not decay as the inverse of the distance squared but at a smaller rate. This slower decay of the gravitational acceleration would effectively describe some of the observations without the need to invoke the existence of dark matter but it also has its own problems, like fine tunning of the parameters in the models. Together with some collaborators, we recently studied a particular galaxy behind the cluster MACS0416 that is gravitationally lensed (or bended) by another galaxy in the same cluster. We named this galaxy the Dragon Kick galaxy because it rejects the MOND hypothesis and confirms the pressence of  a halo of dark matter around the lens galaxy. The Dragon Kick galaxy is shown above as a blue arc that is  super-impossed on the legs of our would be Bruce Lee. Our results will be made public next week but basically we find that the lens galaxy (shown above as a yellowish edge-on galaxy  emerging from the private region of our Bruce Lee) requires a halo around it that aligns perpendicularly with the lens galaxy in order to explain the shape of the lensed blue arc (the Dragon Kick galaxy) . The mass of this invisible halo (the dark matter) is larger than the mass of the lens galaxy and in agreement with what is expected from the standard model that assumes the existence of vast amounts of dark matter in the universe. More Dragon Kick galaxies are expected to be studied soon that could help in providing new clues about the nature of dark matter.

 You can see the original paper here: http://arxiv.org/abs/1409.1578

Science in the 21st century. What can we learn from the BICEP2 experience?

BICEP2It was a big deal in March 2014 when the BICEP2 collaboration announced the detection of primordial gravitational waves, the echo of the Big Bang. A potentially Nobel-winning discovery, later on the same authors, following pressure from the community and evidence of systematic problems in their analysis, admitted that the detection could not be claimed yet and that more data is needed to settle the issue. The European-led Planck mission is expected to clarify the situation later this year. However, whether Planck is able to confirm or reject the hypothesis that gravitational waves where detected, what we know now is that the announcement of the alleged discovery  was premature. This rush for being the first is becoming a growing problem in science that can backfire the scientific community. If the BICEP2 result turns out to be the result of an analysis based on incomplete crucial information, the same publicity the BICEP2 collaboration got when they announced their results may turn back but not just on them but on the entire community.  Public funding is the base for science and will continue being so in the future. The impression the general public gets on how their funds are being spend by the scientific community may determine the amount of funding available for future projects. If scientist  act irresponsibly and rush their results after the sought recognition and the results turn out to be wrong, this will  affect the entire community. It is difficult to control these situations as scientist often suffer of a delusional disease where they believe their results because  they want to believe them. Consequently, in most cases they are acting in good faith when announcing their results but they should always leave the door open to the possibility that something went wrong and honestly point to the uncertainties that may be affecting their conclusions. The BICEP2 collaboration gave the impression for a while that this door was shot and locked but cracks appeared in the door soon after their announcement as a consequence of the pressure form the rest of the scientific community. Planck will soon go through that door and leave it close or wide open …