1108.4021
The outskirts of globular clusters as modified gravity probes
Hernandez, Jimenez
* MOND picture: for a < a0, transition into MOND regime, where the equilibrium velocity scales as v^4 ~ M.
The MOND dropoff observed in outskirts of Galactic globular clusters. (?!? really?) Construct gravitational equilibrium dynamical models for these clusters: inner Newtonian region and outer modified gravity regime---reproduces observed half-light radii, total masses and LOS velocity dispersion profiles. Derive estimated total mass for each system; find asymptotic values of the velocity dispersion profiles consistent with scaling with the fourth root of the total masses, as expected from MOND.
* Which globular clusters are showing this? : Scarpa+ (2004, 2007, 2011)
NGC6171, NGC6341, NGC7078, NGC7099, NGC288
* What are their estimated mass?
* Is the acceleration smaller or larger than solar system velocity? : a0 ~ 1.2e-10 m/s^2
* Pioneer anomaly: At the edge of the solar system (20 AU = 3e9 km, where the Pioneer anomaly shows), unexplained acceleration towards the Sun of (8.74\pm1.33)e-10 m/s^2. Lunar laser ranging experiments have disproved MOND as the source of Pioneer anomaly.
* Is the v^4~M consistent with NFW profile mass distribution?
UCB SPI seminar
CO freeze-out and the origins of chemical complexity
Karin Oberg (CfA)
Organic molecules found in: low- and high-mass protostars, galactic center clouds, protostellar outflows, protoplanetary disks and comets. Demonstrates efficient astrophysical pathways to chemical complexity. Explore such pathways--constrain prebiotic chemistry during planetesimal formation and develop new tracers. Chemical evolution mostly takes place on interstellar grain surfaces, in icy mantles (?). Role of CO freeze-out for ice evolution from clouds to hot cores (?), and also its role in regulating the chemistry in protoplanetary disks. CO snowline in disks is important. Many results depend directly or indirectly on lab simulations of grain surface chemistry. New results on CO photodesorption; other experimental work required for ALMA.
1108.3950
The Cosmic Background Imager 2
Taylor et al.
* Cosmic Background Imager:
13 antennas, 0.9m replaced with 1.4m antennas. Excellent sidelobe and spillover performance at low cost. Off-the-shelf "spun primaries" used, secondary mirrors oversized, shaped relative to ... all these new improvements. Demonstrate performance of telescope and the inter-calibration with previous system using SZ effect on Abell 1689. Enhanced instruemt used to study the CMB, SZ and diffuse galactic emission.
1108.3343
The Atacama Cosmology Telescope: high-resolution SZ array observations of ACT SZE-selected clusters from the Equatorial Strip
Reese, Mroczkowski, et al
Follow-up observations with SZA of optically confirmed galaxy clusters found in the equatorial survey region of ACT (3 clusters). One of them is new--it's also massive (1e15 Msun) and at high-z (z=0.81). SZA observation probes broader range of spatial scales, disentangle cluster decrements from radio point source emission, derive more robust integrated SZE flux and mass estimates than ACT data alone. For 2 clusters, compute integrated SZE signal and derive masses from SZA data only. Abell 2631 has Chandra X-ray-based mass estimate; optical richness also used to estimate cluster masses, shows good agreement with SZE and X-ray. Based on the point sources in SZA, point source contamination is at the <=20% level from some fraction of clusters.
1108.3384
An indirect search from WIMPs in the Sun using 3109.6 days of upward-going muons in Super-K
Tanaka et al.
Search of high-E nu from WIMP annihilation in the Sun, using upmu events in Super-K. Dataset from SKI-SKIII. Searched for excess of nu signal from Sun, compared with expected atmospheric nu BG in three upmu categories: (1) stopping, (2) non-showering, (3) showering. No significant excess observed. Upper limit for muon flux from WIMP (100GeV) were ~5e-15 cm^-2 s^-1; limits spin-dependent WIMP-nucleon scatter cross section in the soft and hard annihilation channels to ~1e-39 cm^-2.
* current DM derection limits are ~1e-41.
1108.3486 (companion paper to 1108.2323)
The US Eclipse Megamovie in 2017: a white paper on a unique outreach event
Hudson, Mcintosh, Habbel, Pasachoff, Peticolas
* 2017: First total eclipse in the continental US since 1979. Another in 2024...
Total eclipse from Oregon to South Carolina. Totality lasts for an hour and a half. Good chance for very high time resolution movie of the event: contain unprecendented information about the physics of the solar corona.
1108.3541
Constraining the axion mass through the astroseismology of the ZZ Ceti star G117-B15A
CArsico, Althaus, Romero, Miller Bertolami, GarcAa-Berro, Isern
* DAV star:
Study astroseismology on the basis of a modern set of fully evolutionary DA white dwarf models with consistent chemical profiles at the core and envelope. Model that closely reproduces the observed pulsation periods of this particular star. Use measured rate of period change for the dominant mode of the pulsating star to impose preliminary upper limit to the mass of the axion. (how in the world do they do that??)
1108.3546
Constraining DM models from a combined analysis of MW satellites with the Fermi LAT
Fermi-LAT collaboration
* good, solid limits
Satelite galaxies of the MW: most promising targets for DM searches in gamma rays (large dynamical M/L ratio, small expected BG from astrophysical sources (i.e., we're not looking into a BH). Apply joint likelihood analysis to 10 satellite galaxies with 24 months of data of Fermi LAT. No DM signal detected. Uncertainty in the DM distribution in the satellites taken into account in deriving robust upper limits on DM models. Annihilation cross section range from 1e-26 cm^3 s^-1 at 5GeV to 5e-23 cm^3/s at 1TeV, depending on the DM annihilation final state. For the first time using gamma rays, able to rule out models with the most generic cross section (~3e-26 cm^3/s for a purely s-wave cross section), w/o assuming additional astrophysical or particle physics boost factors.
1108.3512
Towards a general description of the interior structure of rotating BH
Hamilton
Present a number of proposals about the interior structure (structure where?) of a rotating BH that is accreting slowly. Proposal can possibly be tested with numerical simulations. Triggers "mass inflation instability", which happens with the outgoing and ingoing particles free-falling in the parent Kerr geometry become highly focused along the principal null directions as they approach the "inner horizon" (?). Argue: gravitational waves should behaving in the geometric optics limit, and hence the spacetime should be almost shear-free. Full set of shear-free equations derived. A specific line-element is proposed; argue that it should provide a satisfactory approximation during early inflation. Argue: super-Planckian collision between outgoing and ingoing particles will lead to "entropy production" (?!) brining inflation to an end, and precipitating collapse (?).
* what is "inflation" in a rotating black hole?
* whatever.
1106.4018
Predicted constraints on cosmic string tension from Planck and fugure CMB polarization measurements
Foreman, Moss, Scott
Fisher matrix calculation on the error estimates of cosmic string tension Gmu from Planck and future CMB experiments. Simulations are more general then commonly used in the literature: mean velocity of strings, correlation length of the string network, "wiggliness" are left as free parameters that can be observationally measured. StringFast (new code): efficient computation of the C_l spectra induced by a network of strings. If string parameters left free, the projected constraings on Gmu are larger by x2-7. If Gmu is equal to the current observational maximum, Planck will be able to make a confident detection of strings (bah). If factor of 100 smaller, then cannot detect string tension.
* how does string tension affect C_l? It must leave WL-like signatures, I guess, and the tension give the stringth of such signal?
1108.3989
Three-dimensional hydrodynamic core-collapse SNe simulations for an 11.2 M_sun star with spectral neutrino transport
Takiwaki, Kotake, Suwa
Three-dimensional hydrodynamic core-collapse SNe simulations for an 11.2 M_sun star with spectral neutrino transport
Takiwaki, Kotake, Suwa
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