Day 104

Wednesday.  Still need to plan my work order and priorities.


1110.2165
Processing of polycyclic aromatic hydrocarbons in molecular-loop regions near the Galactic center revealed by AKARI
Kaneda, Ishihara, Mouri, Oyabu, Yamagishi, Kondo, Onaka, Fukui, Kawamura, Torii


AKARI mid-IR diffuse map of Galactic center in 9um (mostly aromatic hydrocarbon IR emissions of carbonaceous grains, at 6.2, 7.7, 8.6, 11.3 um).  9um emission structures to galactic latitude of 2.5 deg, corresponding to NANTEN 12CO (J=1-0) observations.  Surface brightness of 9um suppressed near the foot points of CO loops [what are these loops?].  Find 3.3 um aromatic hydrocarbon emission absent in the region associated with the loop; suggest processing and destruction of carbonaceous grains in the CO molecular loops.


* what on earth is a CO molecular loop?  Listing all the findings without stating significance of each is not appropriate for a abstract!


1110.2168
Star Formation and the Hall Effect
Braiding


Hall diffusion important to the magnetic field behaviour: encountered during the gravitational collapse of molecular cloud cores into protostars.  Hall diffusion also determines the strength of magnetic diffusion and centrifugal shocks that bound the pseudo and rotationally-supported disks; can introduce subshocks that further slow accretion onto the protostar.  It can also even induce rotation in cores that are not initially rotating.  The Hall effect clearly influences the dynamics of gravitational collapse and its role in controlling the magnetic breaking and radial diffusion of the field would be worth exploring.


1110.2172
Multi-zone models of superbursts from accreting neutron stars
Keek, Heger


Superbursts: rare and energetic thermonuclear carbon flashes observed to occur on accreting NSs.  Shock heating alone is sufficient for a bright precursor that follows the shock breakout on a short dynamical time scale due to the fall-back of expanded layers.  Models at the highest accretion rats lack a shock breakout, precursor and the first power law decay component (superbursts generally exhibit a shock breakout, a precursor burst due to shock heating, and a two-component power-law decay).  Ashes of superburst are predominantly composed of Fe, but a superburst leaves a Si-rich layer behind in which the next one ignites.  Difficult to constrain crustal heating; no good match with the observed accretion rate.


1110.2173
The nonlinear evolution of LSS in growing neutrino cosmologies
Baldi


* "growing neutrino cosmology"?


Neutrino lumps forming in the context of Growing Neutrino cosmologies are expected to pulsate as a consequence of the rapid oscillation of the DE scalar field; present results of N-body sims of this scenario.  Also compute realistic distribution of neutrino haloes and determine their impact on the underlying CDM structures.


1110.2177
Halo scale preductions of symmetron modified gravity
Clampitt, Jain, Khoury


* Modified gravity again, Bhuv?


Predictions of symmetron (5th force) modified gravity in DM haloes.  Compare 3 major known screening mechanisms: Vainshtein, Chameleon, and Symmetron around DM sources: discuss differences and observational tests.  Demonstrate host halo environmental screening effect ("blanket screening")  on smaller satellite haloes by solving for the modified forces around a density profile of satellites and host haloes.


* screening effect of what?


1110.2178
The optical gravitational lensing experiment.  High proper mostion stars in the OGLE-III data for magellanic clouds fields
Poleski et al


Search for high proper motion (HPM) stars with mu>100 mas/yr, in the direction of the Magellanic Clouds.  Found 549 HPM stars (uncertainty 0.5 mas/yr).  For 70% of the objects, parallaxes were also measured.  Absolute magnitude and colors show that 21 of the HPM stars are WDs.  Other 23 candidate WDs from colors had no measurable parallaxes.  Also found 27 common proper motion binaries.  Completeness of catalog estimated at >80%.


* the BG info for microlensing.


1110.2182
Supersonic baryon-CDM velocities and a CMB B-mode polarization
Ferraro, Smith, Dvorkin


Supersonic relative velocities between DM and baryonic matter can have significant effect on formation of the first structures in the universe [how?].  Effect still non-negligible during epoch of reionization; generates large-scale anisotropy in the free electron density, which gives rise to CMB B-mode.  Compute B-mode power spectrum and find characteristic shape with peaks at l=200,400... Amplitude of this signal is a free parameter which is related to the dependence of the ionization fraction on the relative baryon-CDM velocity during the epoch of reionization.  Find B-mode signal is undetectably small for currently favored reionization models in which hydrogen is reionized promptly at z~10, although constraints on the signal by future experiments may help constrain models in which partial reionization occurs at higher redshift (e.g. by accretion onto primordial BHs).


1110.2194
Testing the accuracy of radiative cooling approximations in SPH simulations
Wilkins, Clarke


Test polytropic cooling method in SPH (uses local density and potential to estimate the column density and optical depth to each particle, and then uses these quantities to evaluate an approximate expression for the net radiative cooling).  Evaluate algorithm: method OK for spherical systems, but systematically underestimates total cooling rate by a factor of 200 for disk geometries.  Probably dues to the method's systematic over-estimate of the disc column density and optical depth, and doesn't take into account the low column density route for photon escape, normal to the disc plane.  Introduce analytic self-gravitating disc structure method.


1110.2208
How axi-symmetric is the inner HI disc of the MW?
Marasco, Fraternali


Despite the barred potential, the neutral gas in the inner MW (outside of 2kpc) is distributed fairly axi-symmetric.


1110.2245
Some remarks on the methods of investigations of alignment of galaxies
Godlowski


Hawley & Peebles (1975): use tree statistical test for investigations of the galaxy orientation in the large structures.  Some improvement proposed on this method.  Statistical tests: chisq test, Fourier test, Autocorrelation test, and Kolmogorov test.  Mean value (of 247 Abell clusters) compared to simulation results.  Find orientation of galaxies are not random.


1110.2250
Gap opening beyond dead zones by photoevaporation
Morishima


Origin of protoplanetary discs with large inner holes (gaps), "transition discs".  Model takes into account layered accretion: poorly-ionized low-viscosity dead zones are sandwitched by high-viscosity surface layers, and photoevaporative winds induced by X-rays from the central stars.  Gap opens at radius outside a dead zone if mass loss rate due to winds exceeds the mass accretion rate in the dead zone region.  Since the dead zone survives after the gap opens, mass accretion onto the central star continues for a long time.  Model can reproduce large gap sizes and high mass accretion rates seen in observed transition discs.


* what is a "dead zone"?


1110.2294
Query driven visualization of astronomical catalogs
Buddelmeijer, Valentijn


Interactive visualization of astronomical catalogs requires novel techniques due to huge volumes and complex structure of the data.  Present query driven visualization; set process parameters directly from within the visualization.  Implemented in Astro-WISE.


1110.2310
Galaxy cluster number count data constraints on DE
Campanelli, Fogli, Kahniashvili, Marrone, Ratra


Results in substantial agreement with concordance cosmological model.


* they don't say which dataset they're using. 


1110.2334
Probing spectral properties of radio-quiet quasars searched for optical microvariability-II.
Joshi, Chand, Wiita, Gupta, Srianand


For AGN unification: rapid variability important in understanding any intrinsic differences between sources in different classes.  Got spectra for microvariable quasars; emission lines (H_beta and MgII) to determine FWHM and EW due to broad emission line components.  Line widths used to estimate BH masses and Eddington ratio ell; ell is anticorrelated with EW and FWHM.  Luminosity does not seem to correlate with microvariability; no evidence for hypothesis that weak jet component in radio quiet AGNs is responsible for microvariability.


1110.2412
Evolution of violent gravitational disc instability in galaxies: Late stabilization by transition from gas to stellar dominance
Cacciato, Dekel, Genel


Violent instability in high-z, massive, star-forming galactic discs.  Mass and energy conservation under self-regulated instability of 2-component disc of gas and stars. Disk continuously fed by cold gas at cosmological rate; gas forms stars and partially driven away by stellar feedback; gas and stars flow inward through the disk to a central bulge; gravitational energy released by mass inflow down the gravitational potential gradient drives the disc turbulence that maintains the disc unstable with a Toomre instability parmeter Q~1, compensating for the dissipative losses of the gas turbulence and raising the stellar velocity dispersion [what's being compensated?].  Follow velocity dispersion of stars and gas as they heat and cool and search for disc 'stabilization' (marked by a low gas velocity dispersion comparable to the speed of sound, ~10 km/s).  Vary:accreted gas fraction, turbulence dissipation rate, SFR, stellar feedback.  Find: as long as the gas input roughly follows average cosmological rate, the disc instability is a robust phenomenon at high z till z~1, driven by the high surface density and high gas fraction due to intense cosmological accretion.  The discs tend to 'stabilize' at z~0-0.5 as they become dominated by hot stars.  Model parameters are pushed to extreme values, then discs may stabilize as early as z~2, with the gas loss by strong outflows serving as the dominant stabilizing factor.


* what is disc instability in galaxies?


1110.2236
Superluminal neutrinos in a pseudoscalar potential
Sahu, Zhang


Interpret as neutrinos traveling in a pseudoscalar potential generated by a medium.


1110.2293
Neutrinos as hot or warm dark matter
Li, Xing


keV sterile neutrinos could e a good candidate for warm DM.  The beta-decaying (H-3 and Ru-106) and EC-decaying (Ho-163) nuclei are considered as the most promising targets to capture those extremely low energy neutrinos and antineutrinos, respectively.  Calculate capture rates of relic electron neutrinos and antineutrinos against the corresponding beta-decay or EC-decay backgrounds in different flavor mixing schemes.  Direct laboratory measurements of hot or warm DM might not be hopeless in the long term.