We present a large class of new backgrounds that are solutions of type IIB supergravity with a warped AdS 5 factor, non-trivial axion-dilaton, B-field and three-form Ramond-Ramond flux but yet have no five-form flux. We obtain these solutions and many of their variations by judiciously applying non-Abelian and Abelian T-dualities, as well as coordinate shifts to AdS 5 × X 5 IIB supergravity solutions with X 5 = S 5 , T 1,1 , Y p,q . We address a number of issues pertaining to charge quantization in the context of non-Abelian T-duality. We comment on some properties of the expected dual super conformal field theories by studying their CFT central charge holographically. We also use the structure of the supergravity Page charges, central charges and some probe branes to infer aspects of the dual super conformal field theories.

Faraday rotation measurements of the solar corona made with the VLA at frequencies of 1465 and 1665 MHz are reported. The measurements were made along 20 lines of sight to 19 extragalactic radio sources in 2005 March and April. The closest heliocentric distances of the lines of sight ranged from 5.6 to 9.7 R . Measured rotation measures range from À25 to +6 rad m À2 , and perhaps as high as +61 rad m À2 . The purpose of these observations is to probe the three-dimensional structure of the coronal plasma in the heliocentric distance range 5Y10 R , and particularly the strength and structure of the coronal magnetic field. The measured rotation measures are compared with two types of models for the coronal plasma structure. For the majority of the lines of sight, the observed rotation measures are reasonably well represented by the predictions from either type of model. However, 3 or 4 of the 20 lines of sight have large observed-model residuals. These anomalous sources do not seem to be affected by coronal mass ejections (which did occur during the program), but there may be an association between anomalous rotation measures and the presence of streamers along the line of sight. The magnitude of the coronal field necessary to reproduce the majority of the observations is in the range of 46Y120 mG at a fiducial heliocentric distance of 5 R , with a smaller, preferred range of 46Y52 mG.

We confirm the reality of a reversal of the sign of the Faraday Rotation Measure in the Galactic plane in Cygnus (Lazio et al 1990), possibly associated with the Cygnus OB1 association. The rotation measure changes by several hundred rad/m 2 over an angular scale of 2 − 5 • . We show that a simple model of an expanding plasma shell with an enhanced density and magnetic field, consistent with observations of Hα emission in this part of sky, and physically associated with a superbubble of the Cygnus OB1 association, can account for the magnitude and angular scale of this feature.

We show that the near horizon regime of a Kerr–Newman AdS (KNAdS) black hole, given by its two-dimensional analogue a là Robinson and Wilczek (Phys. Rev. Lett.95, 011303 (2005)), is asymptotically AdS2 and dual to a one-dimensional quantum conformal field theory (CFT). The s-wave contribution of the resulting CFT's energy–momentum tensor together with the asymptotic symmetries, generate a centrally extended Virasoro algebra, whose central charge reproduces the Bekenstein–Hawking entropy via Cardy's formula. Our derived central charge also agrees with the near extremal Kerr/CFT correspondence (Phys. Rev. D80, 124008 (2009)) in the appropriate limits. We also compute the Hawking temperature of the KNAdS black hole by coupling its Robinson and Wilczek two-dimensional analogue (RW2DA) to conformal matter.

We present a large class of new backgrounds that are solutions of type II supergravity with a warped AdS 4 factor, non-trivial axion-dilaton, B-field, and three-and five-form Ramond-Ramond fluxes. We obtain these solutions by applying non-Abelian T-dualities with respect to SU(2) or SU(2)/U(1) isometries to reductions to 10d IIA of 11d sugra solutions of the form AdS 4 × Y 7 , with Y 7 = S 7 /Z k , S 7 , M 1,1,1 , Q 1,1,1 and N (1, 1). The main class of reductions to IIA is along the Hopf fiber and leads to solutions of the form AdS 4 × K 6 , where K 6 is Kähler Einstein with K 6 = CP 3 , S 2 × CP 2 , S 2 × S 2 × S 2 ; the first member of this class is dual to the ABJM field theory in the 't Hooft limit. We also consider other less symmetric but susy preserving reductions along circles that are not the Hopf fiber. In the case of N (1, 1) we find an additional breaking of isometries in the NAT-dual background. To initiate the study of some properties of the field theory dual, we explicitly compute the central charge holographically.