Day 46

Wednesday.  Did get SExtractor to work yesterday, now onto SCAMP.  But before that, I gotta make some plots with GGLens.


1107.0009
Confronting 2D delayed-detonation models with light curves and spectra of Type Ia supernovae
Blondin, Kasen, Roepke, Kirshner, Mandel


Compare theoretical SNIa explosions with 251 SNe lightcurves and 2231 (low dispersion) spectra,  and data from literature.  Use commonly used data analysis software (MLCS2k2, SALT2, SNooPy, SNID) to assess how well the models match the data.  Models that fare well lie systematically on the observed width-luminosity relation.  Reject six high-ly asymmetric ignition conditions and a large amount (>1 M_sun) of synthesized 56Ni that yield poor matches to observed SNIa spectra.  Models have general difficulty to match the U-band flux at early times (caused by hot ionized ejecta that affect the subsequent redistribution of flux at longer wavelengths).  Examine ways in which the asymptotic kinetic energy of the explosion affects both the predicted velocity and velocity gradient in the SiII and CaII lines.  Models with asymmetric distribution of 56Ni are found to result in a larger variation of photometric and spectroscopic properties with viewing angle, regardless of the initial ignition setup.  Discuss whether highly anisotropic conditions are ruled out (well, are they?), and how detailed comparison between models and data (light curves and spectra) can lead to better understanding of SN Ia explosion mechanisms.


* Well, how well the the anisotropic conditions constrained?


1107.2665
Toward early-warning detection of gravitational waves from compact binary coalescence
Cannon et al


Rapid detection of compact binary coalescence with a network of advanced gravitational wave detectors will offer unique opportunities--e.g., to observe EM counterpart.  Demonstrate computationally practical filtering strategy that can do early warning.


* how do they do it?


1107.2651
Spatially-resolved spectroscopy of SDSS J0952+2552: a confirmed dual AGN


* I read this one.


You can find dual AGNs from double-peaked narrow OIII emission lines, but they need to be confirmed both by image (AO at Keck) and spectra.  This one is confirmed AGN, type 1 and 2 pair, separated by 4.8kpc.


1107.3151
Segue 3: An old, extremely low luminosity star cluster in the milky way's halo
Fadely, Willman, Geha, Walsh, Munoz, Jerjen, Vargas, Da Costa


Kinematic and photometric properties of Segue 3, a MW companion, with Keck/DEIMOS spetroscopy and Magellan/IMACS g/r band imaging.  Structure and stellar population of Segue 3 studied w/ ML method.  Half-light radius is 2.1pc (26"\pm5") and M_V = 0.0\pm0.8 mag--the least luminous old stellar system known.  Consistent with single stellar population, 12.0Gyr and [Fe/H] = -1.7.  Determine 32 stars associated with Segue 3 via LOS velocities from spectra + photometry; stars w/in 3 half-light radii have velocity dispersion of 1.2 km/s (whoa! that's low); spread in [Fe/H] of < 0.3dex.  Segue 3 is likely and old, faint stellar cluster which contains no significant dark matter.  Find tentative evidence of mass loss through 11 candidate members outside 3 half-light radii (expected).  Interpretation outside this radii is complicated by the coincidence with a previously known halo substructure, may contaminate member sample.


1106.5494
The cosmological impact of luminous TeV blasars I: Implications of plasma instabilities for the intergalactic magnetic field and extragalactic gamma-ray background
Broderick, Chang, Pfrommer


* inverse Compton: photon gains energy upon interaction with (high-kinetic energy) matter.


Inverse Compton cascades initiated by high (>100GeV) energy gamma rays enhance GeV emission of bright, TeV sources; however, this is not seen in bright TeV blazars, and that's used to constrain the intergalactic magnetic field (IGMF); limits on unresolved extragalactic gamma-ray background (EGRB) by Fermi is used to argue against a large number of such objects at high-z.  But plasma-beam instabilities (?) --the "oblique" instability--present a plausible mechanism by which the energy of the produced (presumably particle) pair can be dissipated locally, heating the IGM.  These instabilities grow on timescales shorter than inv-Comp cooling rate, so they suppress cascades.  This is an obstacle in trying to limit the IGMF from the lack of discernible GeV bump in TeV sources; also weakens the Fermi limits upon the evolution of blazar populations (why?).  Specifically, construct TeV-blazar luminosity function from these objects, and find that it is very well described by the quasar luminosity function at z~0.1, shifted to lower luminosity and number densities, suggesting that both classes of sources are regulated by similar processes.  Extending this relationship to higher redshifts show that the magnitude and shape of EGRB above 10GeV is naturally reproduced with this rapidly evolving TeV-blazar luminosity function.


* subtle points being made.


1106.5493
Dark Matter and synchrotron emission from galactic center radio fliaments
Linden, Hooper, Yusef-Zadeh


Non-thermal radio filaments trance magnetic field lines, has hard synchrotron emission spectra.  Origin of filaments not understood.  Light DM particle (5-10GeV) annihilation matches the intensity, spectral shape, and flux variation of NRFs.  NRF explanation also covers excess gamma-ray emission from Galactic center by Fermi-LAT, as well as direct detection from CoGeNT and DAMA/LIBRA.


* I'm curious bout the NRF, but also about the origin of the magnetic field lines.