Tuesday. Went to Münich for an EUCLID meeting, and back. Talked with Tim at the airport lounge, and then at a cafe in Bonn, on the way back. We have similar stories.
1112.2210
Light echoes reveal and unexpectedly cool Eta Carinae during its 19th-century Great Eruption
Rest, Bianco, et al
Eta Carinae: one of the most massive binary stars in the MW. Eruption in 19th century, unique in that it exceeded the Eddington luminosity limit for 10 years. Only 2.3 kpc away: spatially resolved studies of the nebula have constrained the ejected mass and velocity, indicating that at the eruption, it ejected more than 10 Msun in an event that had 10% of the energy of a typical core-collapse SNe without destroying the star. Report discovery of light echoes of Eta Carinae from the 1838-1858 eruption (probably). Spectra of these light echos show only absorption lines, which are blueshifted by -210 km/s, in good agreement with predicted expansion speeds. The light-echo spectra correlated best with those of G2-G5 supergiant spectra, which have effective temperatures of ~5000K. In contrast to the class of extragalactic outbursts assumed to be analogs of Eta Car's Great Eruption, The effective temperature of its outburst is significantly cooler than allowed by standard opaque wind models. This indicates that other physical mechanisms like an energetic blast wave may have triggered and influenced the eruption.
1112.2213
Evidence for inhomogeneous reionizations in the local universe from metal-poor globular cluster systems
Spitler, Romanowsky, Diemand, Strader, Forbes, Moore, Brodie
Observed spatial biasing and kinematics of metal-poor globular star clusters are used to constrain the local reioinization epoch around individual galaxies. Select 3 galaxies located in different environments, the first attempt at constraining the environmental propagation of reionization in the local Universe: The joint constraint agareems remarkably well with WMAP constraint of z_reion for a simple instantaneous model (~10.5).
* how is the galaxy stellar haloes related to the reionization epoch?
1112.2220
The origin of disks and spheroids in simulated galaxies
Sales, Navarro, Theunds, Schaye, White, Frenk, Crain, Vecchia
Assumptions: disk galaxies form in haloes with high angular momentum and quiet [?] recent assembly history, whereas spheroids are the slowly-rotating remnants of repeated merging events. Use cosmo gas sim GIMIC and look at MW galaxy haloes. At z=0, the simulated galaxies exhibit a wide variety of morphologies (from spheroids to pure disks). Morphological features are very poorly correlated with their halo properties: net spin and mergers play a negligible role in the formation of spheroid stars, most of which form in-situ. Coherent alignment of the angular momentum of baryons that accrete over time to form a galaxy is more important. Spheroids tend to form when the spin of newly accreted gas is misaligned with that of the extant galaxy, leading to episodic formation of stars with different kinematics that cancel out the net rotation of the system. Disks, on the other hand, form out of gas that flows in with similar angular momentum to that of earlier-accreted material. In this scenario, most spheroids consist of superpositions of stellar components with distinct kinematics, age, and metallicity, an arrangement that might survive to the present day given the paucity of major mergers. Since angular momentum is acquired largely at turnaround, morphology is imprinted early by the interplay of the tidal field and the shape of the material desntined to form the galaxy.
* what does this say about bulge + disk galaxies?
1112.2260
The role of galaxy interaction in environmental dependence of the star formation activity at z~1.2
Ideue, et al
Interactions and/or mergers in high-density environment could induce star formation in massive galaxies at z~1.2, increasing the fraction of star-forming galaxies with M*>1e10 Msun.
1112.2366
Discovering habitable earths, hot Jupitoers and other close planets with microlensing
Di Stefano
Evidence of close-orbit planets can be found in the low-magnification portion of the light curves generated by the central star.
1112.2479
Feeding compact bulges and SMBH with low angular-momentum cosmic gas at high z
Dubois et al
Cosmo hydro-sim show that significant fraction of the gas in high z rare massive haloes falls nearly radially to their very centre on extremely short timescales, resulting in a compact bulge. Fraction of gas radially falling to the cnter appears to increase with the mass of the halo, argue that this is most likely due to an enhanced cancellation of angular momentum in rarer haloes. This may be the reason why SMBH grow to 1e9 Msun at an epoch when universe is barely 1Gyr old.
1112.2534
Fermi/LAT observations of 1ES 0229+200: implications for extragalactic magnetic fields and background light
Vovk, Taylor ,Semikoz, Neronov
Use blasars to proble Extragalactic background light (EBL) and extragalactic magnetic field (EGMF). Derive constraints on both . Limit on the EBL depends on the EGMF strength and vice versa.
1112.2657
Pixel-z: studying substructure and stellar populations in galaxies out to z~3 using pixel colors 1. Systematics
Welikala, ... Connolly, Koekemoer, Ilbert, Kneib, Zentner, et al
Use pixel colors to study substructure and stellar populations of 467 galaxies in GOODS-VIMOS survey. Study (a) radial gradients of age, SFR, sSFR, and dust, and (b) distribution of these properties within subcomponents such as spiral arms and clumps. Preliminary results from CANDELS survey.
1112.2683
An analysis of constraints on relativistic species from primordial nucleosynthesis and the CMB
Nollett, Holder
Constraints on the number of relativistic species from CMB and light element abundances in comparison with BBN models, updated with nuclear rates. Demonstrate the CMB and BBN are in good agreement, suggesting that the number of relativistic species did not change between the time of BBN and recombination. Level of agreement between BBN and CMB, as well as the agreement with the standard model of prticle physics, depends on systemtaic differences among determinations of the primordial He abundance. Demonstrate that interesting constraints can be derived combining only CMB and D/H observations with BBN theory, suggesting than an improved D/H constraint would be an extremely valuable probe of cosmology.
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