We study the large time behavior of nonnegative solutions to the Cauchy problem for a fast diffusion equation with critical zero order absorption
with
16000747&_mathId=si2.gif&_user=111111111&_pii=S0022039616000747&_rdoc=1&_issn=00220396&md5=7710bdef4dc8eb3a0d40568a26dfd765" title="Click to view the MathML source">mc:=(N−2)+/N<m<1 and
16000747&_mathId=si3.gif&_user=111111111&_pii=S0022039616000747&_rdoc=1&_issn=00220396&md5=15b341ab8c2b1d45f4b5f56b1825c864" title="Click to view the MathML source">q=m+2/N. Given an initial condition
16000747&_mathId=si4.gif&_user=111111111&_pii=S0022039616000747&_rdoc=1&_issn=00220396&md5=a1bcccbe1cf8669ace34a40cd23f54a4" title="Click to view the MathML source">u0 decaying arbitrarily fast at infinity, we show that the asymptotic behavior of the corresponding solution
u is given by a Barenblatt profile with a logarithmic scaling, thereby extending a previous result requiring a specific algebraic lower bound on
16000747&_mathId=si4.gif&_user=111111111&_pii=S0022039616000747&_rdoc=1&_issn=00220396&md5=a1bcccbe1cf8669ace34a40cd23f54a4" title="Click to view the MathML source">u0. A by-product of our analysis is the derivation of sharp gradient estimates and a universal lower bound, which have their own interest and hold true for general exponents
16000747&_mathId=si42.gif&_user=111111111&_pii=S0022039616000747&_rdoc=1&_issn=00220396&md5=366d3a7e9d40cbfd63d3fd12a57806c1" title="Click to view the MathML source">q>1.