Day 398

Good Friday.


1303.6783
Space based microlensing planet searches
Beaulieu, Tisserand, Batista

EUCLID and WFIRST combine exoplanet search and DE characterization.  Space-based microlensing is the optimal approach to providing a true statistical census of planetary systems in the Galaxy, over a range of likely semi-moajor axes.  This census, combined with Kepler, will determine how common Earth-like planets are over a wide range of orbital parameters.  Preset a status report of the results obtained by microlensing on exoplanets and the new objectives of the next generation of ground based wide field imager networks.  Discuss the prospect offered by space based microlensing at 2020-2025.

1303.6896
Gravitational lensing evidence against extended dark matter haloes
Magain, Chantry

Dark matter around early-type galaxies, detected by BG quasar lensing: a robust measure of total mass within the Einstein ring.  The M/L ratio of the lensing galaxies does not depend on radius, from inner galactic regions out to several half-light radii; its value does not exceed the value predicted by stellar population models by more than a factor two, which may be explained by baryonic dark matter alone, without any need for exotic matter.  Results suggest that if DM is present in early-type galaxies, its amount does not exceed the amount of luminous matter and its density follows that of luminous matter, in sharp contrast to what is found from rotation curves of spiral galaxies.

1303.6949
The pesky power asymmetry
Dai, Jeong (Donghui!), Kamionkowski, Chluba

Physical models for the hemispherical power asymmetry in the CMB reported by Planck must satisfy CMB constraints to the homogeneity of the Universe and quasar constraints to power asymmetries.  Survey a variety of models for the power asymmetry and show that consistent models include (1) a modulated scale-dependent isocurvature contribution to the matter power spectrum or (2) a modulation of the reionization optical depth, (3) gravitational-wave amplitude, or (4) scalar spectral index.  Propose further tests to distinguish between the different scenarios.

1303.6959
Cosmological zoom simulations of z=2 galaxies: the impact of galactic outflows
Angles-Alcazar, Dave, Ozel, Oppenheimer

High-res cosmo zoom sims with 200pc resolution at z=2 and various prescriptions for galactic outflows in order to explore the impact of winds on the morphological, dynamical, and structural properties of eight individual z=2 galaxies.  Present a detailed comparison to spatially- and spectrally-resolved Ha and other observations of z~2 galaxies.  Find that simulations without winds produce massive, compact galaxies with low gas fractions, super-solar metallicities, high bulge fractions, and much of the SF concentrated within the inner kpc.  Strong winds are required to maintain high gas fractions, redistribute SF gas over larger scales, and increase the velocity dispersion of simulated galaxies, more in agreement with the large, extended, turbulent disks typical of high-z SF galaxies.  Winds also suppress early SF to produce high-z cosmic SF efficiencies in better agreement with observations.  Sizes, rotation velocities, and velocity dispersions all scale with stellar mass in accord with observations.  Find a diversity of morphological characteristics - among the two most massive galaxies, one resembles a quiescent grand-design spiral while the other is a clumpy disk undergoing a minor merger; the clumps are evident in Ha but not in the stars.  Some galaxies have stellar densities above the threshold for compact ellipticals seen at these redshifts, although these galaxies are SF since quenching feedback are not included.  Rotation curves are generally slowly rising, particularly when calculated using azimuthal velocities rather than enclosed mass.  These results show that cosmological simulations including outflows can produce disk galaxies similar to those observed during the peak epoch of cosmic galaxy growth.

1303.6960
Finding core collapse supernova from the epoch of reionization behind cluster lenses
Pan, Loeb

Utilize GL by galaxy clusters with Einstein radii > 35" in the search for the highest redshift galaxies.  Associated SNe from the epoch of reionization would have their fluxes boosted above the detection threshold, extending their duration of visibility.  Predict JWST will be able to discover lensed core-collapse SNe at z>7-8.

1303.6961
Are super-luminous supernovae and long GRBs produced exclusively in young dense stellar clusters?
van den Heuvel, Zwart

Argue that both the super luminal SNe and long-duration GRBs are exclusive products of dynamical interactions and collisions in young dense star clusters, which are abundant in dwarf galaxies with active SF; present a model.

1303.7121
Cosmological magnetic fields: their generation, evolution and observation
Durrer, Neronov

Review the possible mechanisms for the generation of cosmological B-fields, discuss their evolution in an expanding Universe filled with the cosmic plasma and provide a critical review of the literature on the subject.  Put special emphasis on the prospects for observational tests of the proposed cosmological magneto genesis scenarios using radio and gamma-ray astronomy and UHE CRs.  Argue that primordial B-fields are observationally testable.  Lead to B-fields in the IGM with B-field strength and correlation length in a well-defined range.  Also state the unsolved questions in this open problem, and propose future observations to address them.

1303.7124
Potential of EBL and cosmology studies with the Cherenkov telescope array
Mazin, ... Totani, et al, for the CTA consortium

VHE (E>100 GeV) gamma-rays are absorbed via interactions with low-energy photons from the extragalactic background light (EBL) if the involved photon energies are above the threshold for electron-positron pair production.  The VHE gamma-ray absorption, which is energy dependent and increases strongly with z, distorts the VHE spectra observed from distant objects.  The observed energy spectra of the AGNs carry, therefore, and imprint of the EBL.  The detection of VHE gamma-ray spectra of distant sources (z=0.11-0.54) by current generation imaging atmospheric Cherenkov telescopes (IACTs) enabled to set stronger upper limits on the EBL density, using certain basic assumptions about blazar physics.  Study how the improved sensitivity of Cherenkov Telescope Array (CTA) and its enlarged energy coverage will enlarge knowledge about EBL and its sources.  CTA will deliver a large sample of AGN at different z with detailed measured spectra.  In addition, it will provide the exciting opportunity to use GRBs as probes for the EBL density at high z.  [what is there to EBL besides the CMB?  The CIB?  Why is the EBL so interesting at different z?]

1303.7194
Evidence for AGN-driven outflows in young radio quasars
Kim, etal

NIR spectra of young radio quasars from WFISE; typical redshifts of 1.6-2.5 and bolometric luminosities ~1e47 erg/s.  Based on the intensity ratios of narrow emission lines, find that these objects are mainly powered by AGNs, although SF contribution cannot be completely ruled out.  The host galaxies experience moderate levels of extinction, A(V)~0-1.3 mag [meaning, some dust].  The observed [OIII] luminosities and rest-frame J-band magnitudes constrain the BH masses to lie in the range 1e8.9-9.7 Msun.  From the empirical correlation between BH mass and host galaxy mass, infer stellar masses of 1e11.3-12.2 Msun.  The [OIII] line is exceptionally broad, with FWHM ~1300 to 2100 km/s, significantly larger than that of ordinary distant quasars.  Argue that these large line widths can be explained by jeg-induced outflows, as predicted by theoretical models of AGN feedback.

1303.7206
Ripple effects & oscillations in the broad FeKa line as a prove of massive black hole mergers
McKernan, Ford, Kocsis, Haiman

If a sufficiently massive satellite BH is embedded in a gas disk around a primary SMBH, it can open a empty gap in the disk.  A gap-opening secondary close to the primary will leave an imprint in the broad component of the FeKa emission line, which varies in a unique and predictable manner.  If the gap persists into the innermost disk, the effect consists of a pari of dips in the broad line which ripple blue-ward and red-ward from the line centroid energy respectively, as the gap moves closer to the primary.  This ripple effect could be unambiguously detectable and allow an EM monitoring of massive BH mergers as they occur.  As the mass ratio of the secondary to the primary BH increases to q>0.01, expect the gap to widen, possibly clearing a central cavity in the inner disk, which shows up in the broad FeKa line component.  If the secondary stalls at >100 r_g in its in-migration, due to low co-rotating gas mass, a detectable ripple effect occurs in the broad line component on the disk viscous timescale as the inner disk drains and the outer disk is dammed.  If the secondary maintains an accretion disk within a central cavity, due to dam bursting or leakage, a periodic 'see-saw' oscillation effect is exhibited in the observed line profile.  Demonstrate the range of ripple effect signatures potentially detectable with Astro-H and IXO/Athena, and oscillation effects potentially detectable with XMM or LOFT for a wide variety of merger and disk conditions.  Observations of the ripple effect and periodic oscillations can be used to provide an early warning of gravitational radiation emission from the AGN.

1212.4097
Search for dark matter annihilations in the Sun with the 79-string IceCube detector
IceCube collaboration

Search for muon neutrinos from DM annihilation in the center of the Sun with the 79-string configuration of IceCube.  The DeepCore sub-array is included in the analysis, lowering the energy threshold and extending the search to the austral summer.  The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos.  Upper limits are therefore set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent WIMP-proton cross-sections for WIMP masses in the range 20-5000 GeV.   These are the most stringent spin-dependent WIMP-proton cross-sections limits to date above 35GeV.