Day 143

Friday.  Thanksgiving at Emilio and Giovanna's last night was great fun.  Stayed until 3am.  Journal club went well too (I think).  And I will get the key to the new apartment this Sunday!


1111.5378
First law for BH binaries
Le Tiec, Blanchet, Whiting


* first law of thermodynamics: conservation of work.  Energy can be transformed, but cannot be created nor destroyed.  Change in internal energy of the system is equal to the amount of heat supplied to the system, minus the amount of work performed by the system on its surroundings.  dU = TdS - PdV


Obtain first law for binary [BH] systems of point masses moving along an exact circular orbit.  Calculation valid through 3PN order, and includes contributions of logarithmic terms at 4PN and 5PN orders.  First law of binary point-particle mechanics is derived from first principles in GR, and analogies are drawn with the single and binary black hole cases.  Some consequences of the first law explored for PN spacetimes: a simple relation between the PN binding energy and Detweiler's redshift observable is established.  Determine value of some previously unknown high order PN coefficients in the circular-orbit binding energy.  Propose new gauge invariant notions for the energy and angular momentum of a particle in a binary system.


1111.5486
Pumping the eccentricity of exoplanets by tidal effect
Correia, Boue, Laskar


When the orbit of the planet is excited by an outer companion, tidal effects combined with gravitational interactions may give rise to a secular increasing drift on the eccentricity.  (Usually, tidal interactions lead to progressing damping of the eccentricity.)  This mechanism may explain why some of the moderate close-in exoplanets are observed with substantial eccentricity values.


1111.5491
The contagion of star-formation: its origin
Anathpindika


Dense pockets of cold, molecular gas preclude the formation of stars.  Molecular cloud shocked by interstellar shock-waves propagating at supersonic velocities is examined for the possibility of dense structure-formation and future stellar wombs.  SPH simulation.


1111.5511
VVV DR1: the first data release of the MW bulge and southern plane from the near-infrared ESO public survey VISTA variables in the Via Lactea
Saito et al


ZYJHK survey on the galactic plane.


1111.5544
Constraining CR and magnetic fields in the perseus galaxy cluster with TeV observations by the MAGIC telescopes
MAGIC collaboration


Gamma-ray emission from CR expected in galaxy clusters, from powerful shocks that contribute to a substantial energy density of CRs.  Additional CR sources at AGN and SNe-driven galactic winds.  Detect gamma-ray emission from CR interactions with the ambient clutser gas in Perseus cluster for ~85 hr.  Central radio galaxy NGC 1275 at E>100 Gev has very steep energy spectrum.  Detect no significant gamma-ray excess.  Constrains the average CR-to-thermal pressure ratio to be <= 1-2%, depending on assumptions and the model for CR emission.    Maximum CR acceleration efficiency at structure formation shocks to be 4-9 microG.


1111.5567
Three fluid cosmological model using Lie and Noether symmetries
Tsamparlis, Paliathanasis


FRW flat spacetime with DE, DM and perfect fluid with a linear equation of state.  DM=dust, and DE=V(phi) scalar field with Lie symmetry invariance, selects the exponential scalar field potential.  Require: analytic solution is invariant under the point transformation generated by the Lie symmetry, eliminates DM and leads to a quintessence and phantom cosmological model containing a perfect fluid and scalar field.  ...  find new analytic solutions to quintessence and phantom cosmologies which contain all three fluids.  These solutions compute analytically all main cosmological functions (scale factor, scalar field, Hubble expansion rate, etc.)


* is this something significant?  I don't get it.  I thought these symmetries were meant to imply  conservation laws.


1111.5573
The polytropic approximation and x-ray scaling relations: constraints on gas and dark matter profiles for galaxy groups and clusters
Capelo, Coppi, Natarajan


Find polytropic parameters assuming hydrostatic equilibrium of DM and gas; M-T relation independent of T_xi (temperature at large radii xi) and c_vir (concentration).  A simple theoretical model that accounts for much of the complexity of recent, improved x-ray scaling relations.