%0 Generic %1 Célérier2009 %A Célérier, Marie-Noëlle %A Bolejko, Krzysztof %A Krasiński, Andrzej %D 2009 %K Dark Energy LTB Void %T A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model %U http://arxiv.org/abs/0906.0905 %X Lemaître - Tolman (L--T) toy models with a central observer have been used to study the effect of large scale inhomogeneities on the SN Ia dimming. Claims that a giant void is mandatory to explain away dark energy in this framework are currently dominating. Our aim is to show that L-T models exist that reproduce a few features of the $Łambda$CDM model, but do not contain the giant cosmic void. We propose to use two sets of data - the angular diameter distance together with the redshift-space mass-density and the angular diameter distance together with the expansion rate - both defined on the past null cone as functions of the redshift. We assume that these functions are of the same form as in the $Łambda$CDM model. Using the Mustapha-Hellaby-Ellis algorithm, we numerically transform these initial data into the usual two L-T arbitrary functions and solve the evolution equation to calculate the mass distribution in spacetime. For both models, we find that the current density profile does not exhibit a giant void, but rather a giant hump. However, this hump is not directly observable, since it is in a spacelike relation to a present observer. The alleged existence of the giant void was a consequence of the L-T models used earlier because their generality was limited a priori by needless simplifying assumptions, like, for example, the bang-time function being constant. Instead, one can feed any mass distribution or expansion rate history on the past light cone as initial data to the L-T evolution equation. When a fully general L-T metric is used, the giant void is not implied.

@misc{Célérier2009, abstract = { Lema\^itre - Tolman (L--T) toy models with a central observer have been used to study the effect of large scale inhomogeneities on the SN Ia dimming. Claims that a giant void is mandatory to explain away dark energy in this framework are currently dominating. Our aim is to show that L-T models exist that reproduce a few features of the $\Lambda$CDM model, but do not contain the giant cosmic void. We propose to use two sets of data - the angular diameter distance together with the redshift-space mass-density and the angular diameter distance together with the expansion rate - both defined on the past null cone as functions of the redshift. We assume that these functions are of the same form as in the $\Lambda$CDM model. Using the Mustapha-Hellaby-Ellis algorithm, we numerically transform these initial data into the usual two L-T arbitrary functions and solve the evolution equation to calculate the mass distribution in spacetime. For both models, we find that the current density profile does not exhibit a giant void, but rather a giant hump. However, this hump is not directly observable, since it is in a spacelike relation to a present observer. The alleged existence of the giant void was a consequence of the L-T models used earlier because their generality was limited a priori by needless simplifying assumptions, like, for example, the bang-time function being constant. Instead, one can feed any mass distribution or expansion rate history on the past light cone as initial data to the L-T evolution equation. When a fully general L-T metric is used, the giant void is not implied. }, added-at = {2011-01-31T18:12:04.000+0100}, author = {Célérier, Marie-Noëlle and Bolejko, Krzysztof and Krasiński, Andrzej}, biburl = {https://www.bibsonomy.org/bibtex/2ac632a7aaa40bd49571470cbd2176d33/ad4}, description = {A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model}, interhash = {7f8d27173a17d02c83fa4929a74eb499}, intrahash = {ac632a7aaa40bd49571470cbd2176d33}, keywords = {Dark Energy LTB Void}, note = {cite arxiv:0906.0905 Comment: 25 pages, 20 figures, substantially revised to match the published version, figs. 9 and 19 changed to match the captions}, timestamp = {2011-01-31T18:12:04.000+0100}, title = {A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model}, url = {http://arxiv.org/abs/0906.0905}, year = 2009 }