Day 537

Sunday.

1310.6351
Embedded lensing time delays, the Fermat potential, and the integrated Sachs-Wolfe effect
Chen, Kantowski, Dai

* "The lens equation, which relates the placement and distortion of the images to the real source position in the thin-lens scenario, is obtained by extremizing the time of arrival among all the null paths from the source to the observer (Fermat's principle)"  (From the abstract of Frittelli, Kling, Newman 2002)

Derive the Ferman potential for a spherically symmetric lens embedded in an FLRW cosmology and use it to investigate the late-time ISW.  Present a simple analytical expression for the temperature fluctuation in the CMB across such a lens as a derivative of the lens' Fermat potential.  This formalism is applicable to both linear and NL density evolution scenarios, to arbitrarily large density contrasts, and to all open and closed BG cosmologies.  Apply this formalism to interpret the observed ISW effects extracted through stacking large numbers of cosmic voids and clusters.  For structures co-expanding with the BG cosmology, i.e., for time-independent density contrasts, find that the gravitational lensing time delay alone can produce fluctuations in the CMB temperature of the order of recent observations by Planck.

1310.6358
Confirmation of small dynamical and stellar masses for extreme emission line galaxies at z~2
Maseda, et al

Spectroscopic observations from LBT and VLT reveal kinematically narrow lines (~50 km/s) for a sample of 14 Extreme Emission Line Galaxies (EELGs) at 1.4<z<2.3.  These measurements imply that the total dynamical masses of these systems are low (<3e9 Msun).  Their large [O III] 5007 EWs (500-1100 A) and faint blue continuum emission imply young ages of 10-100 Myr and stellar masses of 1e8-9 Msun, confirming the presence of a violent SB.  The dynamical masses represent the first such determinations for low-mass galaxies at z>1.  The stellar mass formed in this vigorous SB phase represents a large fraction of the total (dynamical) mass, without a significantly massive underlying population of older stars.  The occurrence of such intense events in shallow potentials strongly suggest that SN-driven winds must be of critical importance in the subsequent evolution of these systems.