Day 556

Post-Thanksgiving Monday.  Tuesday.

1311.7147
Radio-loud AGNs at high redshifts and the cosmic microwave background
Ghisellini, et al

How the interaction between the electrons in a relativistic jet and the CMB affects the observable properties of radio-loud AGN at early epochs.  At high z the magnetic energy density in the radio lobes of radio-loud quasars can be exceeded by the energy density of the CMB, because of its (1+z)^4 dependence.  In this case, relativistic electrons cool preferentially by scattering off CMB photons, rather than by synchrotron.  Thus, sources sharing the same intrinsic properties have different extended radio and X-ray luminosities when located at different z: more distant sources are less luminous in radio and more luminous in X-rays than their closer counterparts.  Instead, in compact regions where the local magnetic field still exceeds the CMB in terms of energy density, synchrotron radiation would be unaffected by the presence of the CMB.  Such regions include the compact inter jet and the so-called hot spot in the radio lobes.  The decrease in radio luminosity is larger in misaligned sources, where radio flux is dominated by the extended isotropic component.  These sources can fail detection in current flux limited radio surveys, and therefore they are possibly under-represented […in radio surveys!] in the associated samples.  As the cooling time is longer for lower energy electrons, the radio luminosity deficit due to the CMB photons is less important at low radio frequencies.  Therefore objects not detected so far in current surveys at a few GHz could be picked up by low frequency deep surveys, such as LOFAR and SKA.  Until then, estimate the number of high redshift radio-loud AGNs through the census of their aligned proxies, i.e., blazars.  Indeed, their observed radio emission arises in the inner and strongly magnetized compact core of the relativistic jet, and not affected by inverse Compton scattering off CMB photons.  [At what redshift does this effect become observable?]

Nature
The martian soil as a planetary gas pump
??

* Knusden pump: A pump with no moving parts, using thermal transpiration, the phenomenon that gas molecules drift from the cold end to the hot end of a narrow channel.  This thermal transpiration flow is induced when the boundary walls of the pump have a temperature gradient.  Because the pump is based simply on temperature differences and have no moving parts, it could provide reliable and precise control of gas flow for a variety of applications, such as gas-sensing breath analyzers, chemical weapons detectors, and even in satellites.  From Wikipedia.

Mars has an active surface, with omnipresent small dust particles and larger debris.  With an ambient pressure below 10 mbar (<1% of surface pressure on Earth), its CO2 atmosphere is tenuous.  Aeolian [relating to the action of wind] processes on the surface such as drifting dunes, dust storms and dust devils are nevertheless still active.  The transport of volatiles below the surface, that is, through the porous soil, is unseen but needs to be known for balancing mass flows.  Here, we describe a mechanism of forced convection within porous soils.  At an average ambient gas pressure of 6 mbar, gas flow through the porous ground of Mars by thermal creep is possible and the soil acts as a (Knusden) pump [Higher pressure at the poles, it seems?].  Temperature gradients provided by local and temporal variations in solar insolation lead to systematic gas flows.  Measurements show that the flow rates can outnumber diffusion rates.  Mars is the only body in the Solar System on which this can occur naturally.  Laboratory experiments reveal that the surface of Mars is efficient in cycling gas through layers at least centimeters above and below the soil with a turnover time of only seconds to minutes.
1311.7187
Massive gravity wrapped in the cosmic web
Shim, Lee, Li

Study how the filamentary patter of the cosmic web changes if the true gravity deviates from GR on the large scale.  The f(R) gravity whose strength is controlled to satisfy the current observational constraints on the cluster scale is adopted as our fiducial model and large N-body simulation of high-resolution is utilized for this study.  By applying the minimal spanning tree algorithm to the halo catalogs from the simulation at various epochs, identify the main stems of the rich superclusters located in the most prominent filamentary section of the cosmic web and determine their spatial extents per member cluster as the agree of their straightness.  Found: the f(R) gravity has an effect of significantly bending [in which way?] the superclusters and that the effect becomes stronger as the universe evolves.  Even in the case where the deviation from GR is too small to be detectable by any other observable, the degree of the supercluster straightness exhibits conspicuous difference between the f(R) and the GR models.  Results also imply that the supercluster straightness could be a useful discriminator of f(R ) gravity from the coupled DE since it is shown to evolve differently between the two models.  The degree of the straightness of the rich superclusters should provide a cosmological test of large scale gravity.
1311.7188
Neutrino events at IceCube and the Fermi Bubbles
Lunardini et al

Discuss the possibility that the IceCube neutrino telescope might be observing Fermi Bubbles.  28 events of ~30 TeV; 5-7 more years should be sufficient to discover this flux at high significance.  For lower primary CR cutoff energies, longer running times will be required to overcome the background.