Day 436

Tuesday.

1305.5389
The AGILE science alert system (ASAS)
Trifoglio et al

ASAS habe been developed to provide prompt processing of science data for detection and alerts on gamma-ray galactic and extra galactic transients, gamma-ray bursts, Xe-ray bursts and other transients in the hard X-rays.  The system is distributed among the AGILE data center of Italian space agency, Frascati, and the AGILE team quick look sites (Bologna and Roma).  Present ASAS architecture and performances in the first 2 years of AGILE payload.

1305.5393
Cosmic-ray propagation in molecular clouds
Padovani, Galli

CRs constitute the main ionizing and heating agent in dense, starless, molecular cloud cores.  Re-examine the physical quantities necessary to determine the CR ionization rate (at E<1 GeV and the ionization cross sections), and calculate the ionization rate as a function of the column density of molecular hydrogen.  Available data support the existence of a low-energy component (<100 MeV) of CR electrons or protons responsible for the ionization of diffuse and dense clouds.  Compute the attenuation of the CR flux rate in a cloud core taking into account magnetic focusing and magnetic mirroring, following the propagation of CRs along flux tubes enclosing different amount of mass and mass-to-flux ratios.  Find that mirroring always dominates over focusing, implying a reduction of the CR ionization rate by a factor of 3-4 depending on the position inside the core and the magnetization of the core.

1305.5425
WFIRST-2.4: what every astronomer should know
Spergel, .. Donahue, .. Hirata, .. Perlmutter, .. Rhodes, .. 

WFIRST Science definition team (SDT) presents a design reference mission (DRM) for WFIRST that employs one of the 2.4m, Hubble-quality mirror assemblies recently made available to NASA.  The 2.4m primary mirror enables a mission with greater sensitivity and higher angular resolution than the smaller aperture designs previously considered for WFIRST, increasing both the science return of the primary surveys and the capabilities of WFIRST as a Guest Observer Facility.  The option of adding an on-axis, coronagraphic instrument would enable imaging and spectroscopic studies of planets around nearby stars.  This short article, produced as a companion to the SDT report, summarizes the key points of the WFIRST-2.4 DRM.  Highlights opportunities that WFIRST affords for advances in many fields of astrophysics and cosmology, including DE, the demographics and characterization of exoplanets, the evolution of galaxies and quasars, and teh stellar populations of the MW and its neighbors.

13035.5441
Why is the moon synchronously rotating?
Makarov

If the Moon's spin evolved from faster prograde rates, it could have been captured into a higher spin-orbit resonance than the current 1:1 resonance.  At the current value of orbital eccentricity, the probability of capture into the 3:2 resonance is as high as 0.6, but it strongly depends on the temperature and average viscosity of the Moon's interior.  A warmer, less viscous Moon on a higher-eccentricity orbit is even more easily captured into super-synchronous resonances.  Discuss two likely scenarios for the present spin-orbit state: a cold Moon on a low-eccentricity orbit and a retrograde initial rotation [spin, not orbital I presume].

1305.5471
Super-isothermality within the effective radius and global S-shape pattern in the mass density profile of elliptical galaxies out to the halo virial radius
Chae, Bernardi, Kravtsov

As the title says.  Results suggest that the isothermal profile is not a universal profile for elliptical galaxies, but the pseudo-phase-space density Q(r)=rho(r)/sigma_r(r)^3, where rho(r) is the total density profile and sigma_r(r) is the radial stellar velocity dispersion profile, may well have a universal profile.  Find that the slope of the Q(r) profile is ~-1.8, remarkably similar to the corresponding slope of dark matter halo profile in dissipation-less N-body simulations.

 1305.5519
Gas rotation in galaxy clusters: signatures and detectability in X-rays
Bianconi, Ettori, Nipoti

Study simple models of massive galaxy clusters in which the ICM rotates differentially in equilibrium in the cluster gravitational potential.  Obtain the X-ray surface brightness maps, evaluating the isophote flattening due to the gas rotation.  Using a set of different rotation laws, put constraint on the amplitude of the rotation velocity, finding that rotation curves with peak velocity up to ~600 km/s are consistent with the ellipticity profiles of observed clusters. Convolve each of the models with the instrument response of ASTRO-H X-ray calorimeter to calculate the simulated X-ray spectra at different distance from the X-ray center.  Demonstrate that such an instrument will allow us to measure rotation of the ICM in massive clusters, even with rotation velocities as low as ~100 km/s.

1305.5527
Using CMB polarization to constrain the anomalous nature of the cold spot with an incomplete sky-coverage
Fernandez-Cobos, et al

Cold Spot anomaly in CMB: probe its anomalous nature using X-correlation of temperature and polarization of the CMB fluctuations.  Extend such approach to deal with realistic data sets with a partial sky-coverage.  In particular, exploit the radial and tangential polarization patterns around temperature spots.  Explore the capacity of the method to distinguish between a standard Gaussian CMB scenario and an alternative one, in which the Cold Spot arises from a physical process that does not present correlated polarization features, as a function of the instrumental-noise level.  Consider more in detail the case of an ideal noise-free experiment and those ones with the expected instrumental-noise levels in QUIJOTE and Planck experiments.  Also present an application to WMAP9 data, without being able to obtain firm conclusions, with a significance level of 32%.  In the ideal case, the alternative scenario could be rejected at a significance level of around 1%, whereas for expected noise levels of QUIJOTE and Planck experiments, the corresponding significance levels are 1.5% 
 7.4%, respectively.

Day 435

Monday.  Need to catch up one more day.

1305.5254
The stellar mass growth of brightest cluster galaxies in the IRAC shallow cluster survey
Lin (YT), et al

The details of the stellar mass assembly of BCGs remain an unresolved problem in galaxy formation.  Construct a sample of clusters that form an evolutionary sequence, and apply it to the Spitzer IRAC Shallow Cluster Survey (ISCS) to examine the evolution of BCGs in progenitors of present-day clusters with mass of 2.5-4.5e14 Msun.  Follow the cluster mass growth history extracted from a high-res cosmo sim, and then use an empirical method that infers the cluster mass based on the ranking of cluster luminosity to select high-z clusters of appropriate mass from ISCS to be progenitors of the given set of z=0 clusters.  Find that, between z=1.5 and0 .5, the BCGs have grown in stellar mass by a factor of 2.3, which is well matched by the predictions from a state-of-the-art SAM.  Below z=0.5 see hints of differences in behavior between the model and observation.

1305.5256
Non-parameteric method for measuring gas inhomogeneities from X-ray observations of galaxy clusters
Morandi, Nagai, Cui

Non-parametric method to measure inhomogeneities in the ICM from X-ray observations of galaxy clusters.  Analyze mock Chandra X-ray observations of simulated clusters; show that new method enables the accurate recovery of the 3D gas density and gas clumping factor profiles out to large radii of galaxy clusters.  Then apply this method to observations of Abell 1935 and present the first determination of the gas clumping factor from the X-ray cluster data.  Find that the gas clumping factor in Abell 1835 increases with radius and reaches ~2-3 at r=R200.  This is in good agreement with the predictions of hydro sims, but it is significantly below the values inferred from recent Suzaku observations.  Further show that the radial increasing gas clumping factor causes flattening of the derived entropy profile of the ICM and affects physical interpretation of the cluster gas structure, especially at the large cluster-centric radii.  New technique should be used for improving the understanding of the cluster structure and to advance the use of galaxy clusters as cosmological probes, by helping to exploit rich datasets provided by Chandra and XMM-Newton X-ray space telescopes.

1305.5257
Deep LBT/LUCI spectroscopy of a Lyman-alpha emitter candidate at z~7.7
Jiang, ... Egami, et al

A non-detection of Lya emission line of the z~7.7 candidate (brightest among the 4 candidates).  Puts a strong constraint on the LF at the bright end.

1305.5265
On the offset of barred galaxies from the black hole M_BH-sigma relationship
Brown et al

Use collisionless N-body sims to determine how the growth of a SMBH influences the nuclear kinematics in both barred and unbarred galaxies.  In the presence of a bar, the increase in the velocity dispersion sigma (within the effective radius) due to the growth of an SMBH is on average <=10%, whereas the increase is only ~4% in an unbarred galaxy.  In a barred galaxy, the increase results from a combination of three separate factors: (a) orientation and inclination effects, (b) angular momentum transport by the bar that results in an increase in the central mass density, (c) an increase in the vertical and radial velocity anisotropy of stars in the vicinity of the SMBH.  In contrast the growth of the SMBH in an unbarred galaxy causes the velocity distribution in the inner part of the nucleus to become less radially anisotropic.  Argue that using an axisymmetric stellar dynamical modeling code to measure SMBH masses in barred galaxies could result in a slight overestimate of the derived M_BH.  Conclude that the growth of a black hole in the presence of a bar could result in an offset in sigma, perhaps partially accounting for the claimed offset of barred galaxies and pseudo-bulges from the M-BH-sigma relation for unbarred galaxies.  If the BH grows significantly in a pre-existing barred galaxy, the resultant secular evolution would alter both the mass and velocity dispersion of the host bulge.

Day 434

Sunday.  One week behind.

1305.3608
Multi-color detection of gravitational arcs: method and new candidates
Maturi, Mizera, Seidel

Would like a more complete, large sample and unbiased methods of selecting candidates: A number of methods for the automatic detection of arcs have been proposed in the literature, but large amounts of spurious detections retrieved by these methods forces observed to visually inspect thousands of candidates per square degree in order to clean the samples, is subjective.  Study the statistical properties of colors of gravitational arcs; find that most of them lie in a relatively small region of the color-color diagram (g-r, r-i).  Support this observational evidence by studying lensing cross section, which peaks for sources at z~1, where the source-galaxy population is dominated by galaxies with large SF regions and hence well defined colors.  The use of this distinctive feature, in combination with an automatic arcfinder, reduces sample contamination by a factor of 6-7.  Test performance of the method against 37 sqdeg of the CARS survey, detecting 73 new arc candidates [before or after visual inspection?].

1305.3630
Is the black hole in NGC1277 really over-massive?
Emsellem

Revisit this claim by examining the predictions from dynamical realizations based on new MGE models [what is that??].  Realizations fit the observed photometry: M/L is fixed following scaling relations which predict a Salpeter-like IMF.  A model without a BH provides a surprising good fit of the observed kinematics outside the unresolved central region, but not, as expected, of the central dispersion and h4 values [what's that??].  A model with MBH of 5e9 Msun allows to fit the dispersion profile, consistent with models fit the same mass and M/L in vdB+12 [what's that?  What was the original mass?].  The h4 value only off by 2 sigma; a slightly varying M/L or the addition of high velocity stars would further lower the need for a very massive BH.  These results do not rule out the presence of an over-massive BH at the center of NGC1277, but leads them to advocate the use of 3-sigma CL for derived MBH as better, more conservative, guidelines for such studies.  [seems like a good paper, but the abstract is not very informative to those outside the field.]

1305.3652
The future of the Sun: an evolved solar twin revealed by CoRoT
do Nascimento, et al

The question of whether the Sun is peculiar within the class of solar-type stars has been the subject of active investigation over the past 3 decades.  Although several solar twins have been found with stellar parameter similar to those of the Sun (albeit in a range of Li abundances and with somewhat different compositions), their rotation periods are unknown, except for 18 Sco, which is younger than the Sun and with a rotation period shorter than solar [why is it that rotation period is important?  What are the other characteristics for comparison?  Metal abundance?  Mass?  Spectra?  Size?  (the latter three of course should be very similar if we're looking for a Sun-like G star)  Age?  Activity level?].  Difficult to obtain periods for stars of solar age from ground-based observations, as low activity level imply a shallow rotational modulation of their light curve [and what's "activity level" anyways?  The sun spots?].   CoRoT provides spaced-based long time series from which the rotation periods of solar twins as old as the Sun could be estimated.  Based on high S/N high res spectroscopic observations from Subaru, Show that the star CoRoT Sol 1 is a somewhat evolved solar twin with a low Li abundance.  Its rotation period is 29pm5 days, compatible with its age (6.7 Gyr) and low lithium content A(Li) < 0.85 dex [does older imply lower Li (consumption of Li)?].  This twin seems to have enhanced abundances of the refractory elements wrt to the Sun, a typical characteristic of most nearby twins [what does it mean to have refactory elements abundance/depleted?  Refractory <=> Volatile.  Refractory elements are: Ca, Al, U, Ti, Ce, Eu, Gd, W, Zr, Th].   This is the only solar twin older than the Sun for which a rotation period has been determined [so far].  

1305.3656
Ultra compact dwarf galaxy formation by tidal stripping of nucleated dwarf galaxies
Pfeffer, Boumgardt

UCDs and dwarf galaxy nuclei have many common properties, such as internal velocity dispersions and color-mag trends, suggesting tidally stripped dwarf galaxies as possible UCD origin.  But UCDs typically have sizes more than twice as large as nuclei as the same luminosity.  Use particle-mesh sims to study tidal stripping in a Virgo-like galaxy cluster.  Find that motion in spherical potentials, where close passages happen many times, leads to the formation of compact (r_h<20pc) star clusters/UCDs.  In contrast, orbital motion where close passages happen only once or twice leads to the formation of extended objects which are large enough to account for the full range of observed UCD sizes.  For such motion, find that dwarf galaxies need close pericenter passages with distances <10 kpc to undergo strong enough stripping so that UCD formation is possible.  As tidal stripping produces objects with similar properties to UCDs, estimates suggest dwarf galaxies have been destroyed in sufficient numbers to explain the observed number in UCDs in M87; consider tidal stripping to be a likely origin of UCDs.  However, comparison with cosmological simulations is needed to determine if the number and spatial distribution of UCDs formed by tidal stripping matches the observations of UCDs in galaxy clusters.

1305.3909
Measurement of atmospheric neutrino oscillations with IceCube
The IceCube Collaboration

Disappearance of low-energy upward-going muon neutrinos observed; the non-oscillation hypothesis rejected with more than 5 sigma significance.  In a two-neutrino flavor formalism, data best described by the atmospheric neutrino oscillation parameters Delta m^2_23=2.3 pm 0.5 10e3 eV^2 and sin^2(2 theta_23)>0.93; maximum mixing favored.

1305.3914
Anchors for the cosmic distance scale: the Cepheid QZ Normae in the Open Cluster NGC 6067
Majaess et al

Assess the membership of 3 Cephieds to the open cluster NGC 6067 whose distance is [presumably] well known (at 1.75pm0.10 kpc from BVJH photometry), determine that ZA Nor and V340 Nor are, but GU Nor isn't.  QZ nor is within cluster bounds, and should be employed as a calibrator for the cosmic distance scale.

1305.3915
H3+ spectroscopy and the ionization rate of molecular hydrogen in the central few parsecs of the galaxy
Goto et al

The elevated CR ionization rate (compared to outside the Galactic center) is still 4 orders of magnitude too short to match the proton energy spectrum as inferred from the recent discovery of the TeV gamma-ray source in the vicinity of Sgr A*.

1305.3917
A statistical relation between the X-ray spectral index and Eddington ratio of active galactic nuclei in deep surveys
Brightman et al

From a sample of 69 X-ray bright sources (>250 counts) where Gamma can be measured with greatest precision, estimate L_Bol, and find statistically significant correlation between Gamma and lambda_Edd, which is highly significant.  A statistically significant correlation between Gamma and the FWHM of the optical lines is confirmed, but at lower significance than with lambda_Edd indicating that lambda_Edd is the key parameter driving conditions in the corona.  

1305.3921
CMB constraints on tensor-to-scalar ratio r
Lau, Tang, Chu

Make a forecast of the constraints on r for PLANCK taking into account the general reionization scenario and cut-sky effects.  Applying an N-pt interpolation analysis on the reionization history, the bias induced by the instantaneous reionizatoin assumption is removed and the value of r is constrained within 5% error, if the true value of r is greater than about 0.1.

1305.3999
Complete infrared spectral energy distributions of mm detected quasars at z>5
Leipski, ... Fan, ... Rix et al

FIR photometry of 11 quasars at z>5; perform full SED fits over the rest-frame lambda range 0.1-400mu for hose with good Herschel detections [is that the full 11 sample?  probably not].  Fits reveal the need for an additional FIR component besides the emission from a dusty AGN-powered torus.  This additional FIR component has temperatures of T_FIR~40-60K with L(8-1000mu) of 1e13 Lsun (accounting for 25-60% of the bolometric FIR luminosity).  If the FIR dust emission is due to SF it would suggest SFR in excess of 1000 Msun per year.  Show that at log wavelengths (lambda_rest>50mu) the contribution of the AGN-powered torus emission is negligible.  This explains how previous FIR studies of high-z quasars that relied on single component fits to (ground-based) observations at lambda_obs>350 mu reached T_FIR and L_FIR values similar to our complete SED fits.  ...

1305.4033
Consistency tests for Planck and WMAP in the low multiple domain
Frejsel, Hansen, Liu

Take difference between different maps, assume that difference is solely due to systematics, noise, FG and other sources, and is uncorrelated to the precise representation of CMB.  In the 3 Planck maps, no correlation found (wrt 10000 random Gaussian simulated maps).  Additionally investigate difference between WMAP ILC 9yr and 7yr map.  Difference significantly correlated with WMAP 9yr map, possibly more contaminated than the 7yr map.

1305.4113
Neutrino signal from extended Galactic sources in IceCube
Tchernin et al

Based on the observed spectral characteristics of the pion decay gamma-ray diffuse emission observed by Fermi/LAT >100 GeV, compare the neutrino flux calculated with the sensitivity of IceCube for the detection of extended sources.  After 20 years of exposure, can detect Cygnus (the only source in the northern hemisphere).  ...

1305.4123
Galactic PeV Neutrinos
Gupta

IceCube detected two neutrinos with 1-10 PeV, they might have originated from Galactic or extragalactic sources of CRs.  Consider hadronic interactions of the diffuse very high energy CRs with the ISM within the Galaxy to explain the PeV neutrino events detected in IceCube.  Also expect PeV gamma ray events along with the neutrino events if the observed PeV neutrinos where produced within the Galaxy in hadronic interactions.  PeV gamma rays are unlikely to reach us from sources outside the Galaxy due to pair production with CMB.  Suggest that in future with simultaneous detections of PeV gamma rays and neutrinos it would be possible to distinguish between Galactic and extragalactic origins of very high energy neutrinos.

1305.4174
Solar-cycle related variation of solar differential rotation
Li, et al

Investigate solar-cycle related variation of differential rotation, based on data from 1976 to 2008.  Differentiation of rotation rate pronounced at the ascending part of Schwabe cycle [the 11 year solar cycle, which can vary from 8-14 years/cycle, and is actually 22 year, taking the B-field orientation into account] than at the descending part, on average.  The differential rotation coefficient B, representing the latitudinal gradient of rotation, may be divided into 3 parts within a Schwabe cycle.  (1) start to the 4th year of Schwabe cycle [what is the beginning of Schwabe cycle?], within which the absolute B is approximately a constant; (2) 4th to 7th year, within which absolute B decreases; (3) 7th year to the end, in which absolute B increases.  Strong B-fields repress differentiation of rotation rates, so that rotation rates show less pronounced differentiations, but weak B-fields seem to just reflect differentiation of rotation rates.  The solar-cycle related variation of solar differential rotation is the result of both the latitudinal migration of the surface torsional pattern and the repression of differentiation of rotation rates by strong magnetic activity [I changed the word order a bit, I hope it means the same thing (or what was intended)].

1305.4176
Unveiling the corona of the Milky Way via ram-pressure stripping of dwarf satellites
Gatto et al

The spatial segregation between dSphs and dIrrs in the Local Group has long been regarded as evidence of an interaction with their host galaxies.  Assume that ram-pressure stripping is the dominant mechanism that removed gas from the dSphs and use this to derive a lower bound on the density of the corona of the MW at large distances  (50-90 kpc) from the Galactic center.  Also derive an upper bound by demanding that the ISM of the dSphs is in pressure equilibrium with the hot corona.  Consider Sextans and Carina dwarfs with well-determined orbits and star formation histories.  Approach introduces several novel features: use the measured SFH of the dwarfs to derive the time at which they last lost their gas, and their internal gas density at that time; use a large suite of 2d hydro sims to model the gas stripping; and include SNe feedback tied to the gas content.  Despite having very different orbits and SFH, find results for the two dSphs that are in excellent agreement with one another.  Derive an average particle density of the corona of the MW at 50-90 kpc in the range 1.3-3.6 e-4 cm^-3.  Including additional constraints from X-ray emission limits and pulsar dispersion measurements, extrapolate Galactic coronal density profiles and estimate the fraction of baryons that can exist within the virial radius of the MW.  For an isothermal corona (T=1.8e6K), this is small, 10-20% of the universal baryon fraction.  Only a hot (T=3e6K) and adiabatic corona can contain all of the Galaxy's missing baryons.  Models for the MW must explain why its corona is in a hot adiabatic thermal state or why a large fraction of its baryons lie beyond the virial radius.

1305.4184
Searching for cooling signatures in strong lensing galaxy clusters: evidence against baryons shaping the matter distribution in cluster cores
Blanchard, .. Dahle, Gladders, et al

The process by which the mass density profile of certain galaxy clusters become centrally concentrated enough to produce high SL cross-sections is not well understood.  It has been suggested that the baryonic condensation of the ICM due to cooling may drag DM to the cores and thus steepen the profile.  In this work, search for evidence of ongoing ICM cooling in a well-defined sample of SL selected galaxy clusters in the range of 0.1<z<0.6.  Based on known correlations between the ICM cooling rate and both optical emission line luminosity and SF, we measure, for a sample of 89 SL clusters, the fraction of clusters that that have [OII]3727 emission in their BCG.  Find that the fraction of line-emitting BCGs is constant as a function of redshift for z>0.2 and show no statistically significant deviation from the total cluster population.  Specific SFRs, as tranced by the strength of the 4000 A break, D_4000, are also consistent with the general cluster population.  Finally, use optical imaging of the SL clusters to measure the angular separation R_arc between the arc and the center of mass of each lensing cluster in our sample and test for evidence of changing [OII] emission and D_4000 as a function of R_arc, a proxy observable for SL cross-sections.  D_4000 is constant with all values of R_arc, and the [OII] emission fractions show no dependence on R_arc for r_arc > 10" and only very marginal evidence of increased weak [OII] emission for systems with R_arc<10".  These results argue against the ability of baryonic cooling associated with cool core activity in the cores of galaxy clusters to strongly modify the underlying DM potential, leading to an increase in SL cross-sections.

1305.4364
HERMES: simulating the propagation of ultra-high energy cosmic rays
De Domenico

UHECR cannot prescind from the study of their propagation in the Universe.  HERMES is an ad hoc Monte Carlo code developed for UHECR propagation; modeling adopted to simulate the cosmology, B-fields, the interactions with relic photons, and the production of secondary particles.  Provide an estimation of the surviving probability of UHE protons, the GZK horizons of nuclei and the all-particle spectrum observed at Earth in different astrophysical scenarios.  Sow the expected arrival direction distribution of UHECR produced from nearby candidate sources.  A stable version of HERMES will be released in the next future for public use together with libraries of already propagated nuclei to allow the community to perform mass composition and energy spectrum analysis with this simulator.

1305.4380
The dust environment of main-belt comet P/2012 T1 (PANSTARRS)
Moreno et al

Observe comet [what is its orbital period?] at six epochs from Nov 2012 to Feb 2013, with the aim of monitoring its dust environment.  The dust tails brightness and morphology are best interpreted in terms of a model of sustained dust emission spanning 4 to 6 months.  The dust mass ejected is estimated at 6-25e6 kg.  Assume a time-independent power-law size distribution function, with particles in the micrometer to centimeter size range.  Based on the quality of the fits to the isophote fields, an anisotropic emission pattern is favored against an isotropic one, in which the particle ejection is concentrated toward high latitudes (pm 45 deg to pm 90 deg) in a highly obliquity object (I=80 deg) [obliquity = angle between orbital plane and that of the celestial equator].  This seasonally-driven ejection behavior, along wit the modeled particle ejection velocities, are in remarkable agreement to those found in another comet P/2010 R2 (La Sagra).

1305.4613
A maximum likelihood approach to estimating correlation functions
Baxter, Rozo

Define a ML estimator for the correlation function xi that uses the same pair counting observables (D, R, DD, DR, RR) as the standard Landy and Szalay (1993; LS) estimator.  The ML estimator outperforms the LS estimator in that it results in smaller measurement errors at any fixed random point density.  Put another way, the ML estimator can reach the same precision as the LS estimator with a significantly smaller random point catalog.  These gains are achieved without significantly increasing the computational requirements for estimating xi.  Quantify the relative improvement of the ML estimator over the LS estimator, and discuss the regimes under which these improvements are most significant.  Present a short guide on how to implement the ML estimator, and emphasize that the code alterations required to switch from a LS to a ML estimator are minimal.

1305.4930
The rapid assembly of an elliptical galaxy of 400 billion solar masses at a redshift of 2.3
Fu, Cooray, ... Boylan-Kolchin, et al

Stellar archeology shoes that massive elliptical galaxies today formed rapidly about ten billion  years ago with SFR above several hundred solar masses per year (Msun/yr).  THeir progenitors are likely the sub-millimeter-bright galaxies (SMGs) at z>2.  While SMGs mean molecular gas mass of 5e10 Msun can explain the formation of typical elliptical galaxies, it is inadequate to form ellipticals that already have stellar masses above 2e11 Msun at z~2.  Report multi-wavelength high-resolution observations of a rare merger of two massive SMBs at z=2.3.  The system is currently forming stars at a tremendous rate of 2000 Msun/yr.  With a SF efficiency an order-of-magnitude grater than that of normal galaxies, it will quench the SF by exhausting the gas reservoir in only ~200 million years.  At a projected separation of 19 kpc, the two massive starbursts are about to merger and form a passive elliptical galaxy with a stellar mass of ~4e11 Msun.  Observations show taht gas-rich major galaxy mergers, concurrent with intense SF, can form the most massive elliptical galaxies by z~1.5.

1305.4931
A physical model for cosmological simulations of galaxy formation: multi-epoch validation
Torrey, Vogelsberger, Genel, Sijacki, Springel, Hernquist

Present a multi-epoch analysis of the galaxy populations formed within the cosmological hydrodynamical simulations presented in Vogelsberger+ (2013).  These simulations explore the performance of a recently implemented feedback model which includes primordial and metal line radiative cooling with self-shielding corrections; stellar evolution with associated mass loss and chemical enrichment; feedback by stellar winds; black hole seeding, growth and merging; and AGN quasar- and radio-mode heating with a phenomenological prescription for AGN electro-magnetic feedback.  Illustrated the impact of the model parameter choices on the resulting simulated galaxy population properties at high and intermediate redshifts.  Demonstrate that the scheme is capable of producing galaxy populations that broadly reproduce the observed galaxy stellar mass function extending from redshift z=0 to 3.  Also characterize the evolving galactic B-band luminosity function, stellar mass to halo mass ratio, SF main sequence, TF relation, and gas-phase mass-metallicity relation and confront them against recent observational estimates.  This detailed comparison allows validation of elements of the feedback model, while also identifying areas of tension that will be addressed in future work.

1305.5109
Excellent daytime seeing at Dome Fuji on the Antarctic plateau
Okita et al

The free atmosphere seeing is ~0.2", and the height of the surface boundary layer can be as low as ~11m.  Seeing often has a local minimum of ~0.3" near 18h local time.  Some periods of excellent seeing, 0.3" or smaller observed, sometimes extending for several hours at local midnight.  Median seeing is higher, at 0.52"---believed to be caused by periods when the telescope was within the turbulent boundary layer.  The diurnal variation of the daytime seeing  at Dome Fuji is similar to that reported for Dome C; the height of surface boundary layer is consistent with previous simulations.

1305.5177
Infrared background signatures of the first black holes
Yue, et al

As the title says.  For z~12 direct-collapse BHs forming at virial temperature of 1e4K.

1305.5178
Formation of the first stars
Bromm

Primordial SF is unique in that its initial conditions can be directly inferred from the LCDM model of cosmological structure formation.  Combined with gas cooling that is mediated via molecular hydrogen, one can robustly identify the regions of primordial SF, the so-called mini-halos, having total masses of 1e6Msun and collapsing at redshift z~20-30.  Within this framework, a number of studies have defined a preliminary standard model, with the main result that the first stars were predominantly massive.  This model has recently been modified to include a ubiquitous made of fragmentation in the protostellar disks, such that the typical outcome of primordial SF may be the formation of a binary or small multiple stellar system.  Discuss extensions to this standard picture due to the presence of dynamically significant magnetic fields, of heating from self-annihilating WIMP dark matter, or cosmic rays.  Conclude by discussing possible strategies to empirically test theoretical models.

1305.5249
The extragalactic background light from the measurements of the attenuation of high-energy gamma-ray spectrum
Gong, Cooray

As the title says.  Use absorption features of the gamma-rays from blazars as seen by Fermi to explore the EBL flux density and constraint the EBL spectrum SFRD and photon escape fraction from galaxies out to z=6.  Results consistent with existing measurements.  Find larger escape fraction at high redshifts, especially at z=3, compared to the results from the recent Lya measurements.  The average SFRD at z>3 obtained here is higher than the results from the UV data but agrees well with that from the gamma-ray burst observations.  SFRD at z>6 obtained here is sufficiently high enough to reionize the universe.

Day 433

Wednesday.  One week behind.
1350.3020
Turbulence in the SuperModel: mass reconstruction with nonthermal pressure for Abell 1835
Fusco-Femiano, Lapi

Total mass derived from X-ray is biased low in a large number of clusters when compared with the mass estimated via SL and WL.  Some Suzaku and Chandra observation show steep temperature gradients in relaxed clusters that, assuming hydrostatic equilibrium, imply an unphysical decreasing mass profile; the gas mass fraction appears to be inconsistent with cosmic value.  Such findings can be interpreted as an evidence for an additional nonthermal pressure in the outskirts of these clusters.  This nonthermal component may be due to turbulence stirred by residual bulk motions of extragalactic gas infalling into the cluster.  SuperModel formalism can include in the equilibrium a nonthermal component whose level and distribution are derived imposing that the gas mass fraction f_gas equals the cosmic value at the virial radius.  including such a nonthermal component, and reconstruct from X-rays an increasing mass profile consistent with the hydrostatic equilibrium also in the cluster outskirts and in agreement at the virial boundary with the WL value.  The increasing f_gas profile confirms that the baryons are not missing but located at the cluster outskirts.

1305.4633
Evolution of giant molecular clouds in nearby galaxies
Koda

GMC evolution appears different between the local, predominantly atom-rich small galaxies and a typical spiral galaxy with a rich molecular content.  GMCs exist almost exclusively along HI spiral arms and filaments in the disks of local small galaxies, suggesting that GMCs form and end their short lives there.  In a more molecular rich environment, GMCs are present everywhere independent of HI structures.  The molecular gas fraction remains high and almost constant during arm passage into the next inter-arm region.  The gas remains molecular, presumably in GMCs for a long time.  A transitional case has been found recently in the central regions of the atom-rich galaxy M33; GMCs do not coincide with HI there.  Evolution of the physical conditions of molecular gas from spiral arms to inter-arm regions is also being revealed in molecule-rich galaxies.  An increase of the CO J=2-1 and 1-0 line ratio in spiral arms in M51 suggests density and/or temperature increases by a factor of 2-3 in GMCs in the arms, compared to their counterparts in the inter-arm regions.  An analysis of high-resolution MW survey data revealed that the fraction of dense (or warm) clumps increases dramatically in the spiral arms.

1305.4641
Third-epoch Magellatnic cloud proper motions II: the Large Magellanic Cloud rotation field in three dimensions
van der Marel, Kallivayalil

LMC large-scale rotation on full 3-dimensional velocity measurements, based on HST proper motion (PM) measurements for stars in 22 fields, with existing LoS velocity measurements of 6790 stars.  Interpret these data with a model of circular rotation in a flat disk.  PM and LoS data paint a consistent picture of the LMC rotation and their combination yields several new insights.  The PM data imply a stellar dynamical center that coincides with the HI dynamical center, and a rotation curve amplitude consistent with that inferred from LoS velocity studies. The implied disk viewing angles agree with the range of values found in the literature, but continue to indicate variations with stellar population and/or radius.  Young (RSG) stars rotate faster than old (RGB/AGB) stars due to asymmetric drift.  Outside the central region, the circular velocity is approximately flat at 91pm19 km/s.  This is consistent with baryonic TF relation, and implies an enclosed mass M(8.7 kpc)=1.7e10 Msun.  The virial mass is larger and depends on the full extent of the dark halo.  The tidal radius is 22.3 kpc (24 deg).  Combination of the PM and LoS data yields kinematic distance estimates for the LMC, but these are not yet competitive with other methods.

1305.4642
One-point remapping of Lagrangian perturbation theory in the mildly non-linear regime of cosmic structure formation
Leclercq et al

Remap by replacing the one-point distribution of a relevant quantity (the Eulerian density contrast of the Lagrangian divergence of the displacement field) by one which accounts for the full gravitational dynamics.  Obtain a physically more pertinent density field on a point-by-point basis, while also improving higher-order statistics as predicted by LPT.  Improves one-, two- and three-point statistics at scales smaller than 60 Mpc/h.

1305.4768
The host haloes of OI absorbers in the reionization epoch
Finlator, Munoz, Oppenheimer, Oh, Özel, Dave

Radiation hydrodynamic simulation that models the growth of galaxies and the extragalactic UV ionizing background (EUVB) self-consistently to study the sources of OI absorption during the H reionization epoch.  Diffuse regions in the IGM are reionzed before they are enriched; hence OI absorption is closely associated with DM haloes.  At z=10, all haloes above the hydrogen cooling limit [10^4 K?] produce visible absorption out to a substantial fraction of the virial radius.  As reionization proceeds, the nascent EUVB ionized and removes gas from low-mass haloes, leading to a cutoff mass below which the geometric cross section for producing observable absorption vanishes.  The cutoff grows from 1e8 at z=10 to 1e8.4 at z=5.  This is 10-100 times less massive than the host haloes of LBGs and LAEs, suggesting that OI absorption probes the mass scale of ionizing sources that drove reionization more directly.  OI absorbers are predicted to have neutral hydrogen columns of 1e19-21 cm^-2 suggesting a close resemblance between objects selected in OI and HI.  The predicted abundance of OI absorbers at z=6 is in reasonable agreement with observations although in detail it may be slightly low, consistent with evidence from the Lya forest that the predicted EUVB is slightly too strong.  Also consider the upper limits on the OI column density of the absorber in the FG of the z=7.085 quasar and find that they cannot be satisfied by halo gas because gas at the observed HI column density enriches too quickly.  By contrast, gas at less than one third the mean density readily satisfies the constraints at z>=7.  Hence the FG absorption in this quasar likely originates in the diffuse IGM rather than in a discrete system.

1305.3269
Detection of X-rays from the jet-driving symbiotic star Hen 3-1341
Stute

Hen 3 is a symbiotic binary system consisting of a WD and a RG star that is one of about 10 symbiotics that show hints of jets.  The bipolar jets have been detected through displaced components of emission lines during its outburst from 1998 to 2004, but these components disappeared when Hen 3 reached quiescence.  In 2012, Hen 3 started a new outburst with the emergence of new bipolar jets.  ToO observations with 10 ks exposure to probe the interaction of the jet with the ambient medium and also the accretion onto the WD, as well as quiescence observation of 10 ks in 2010.  Detect X-ray emission during quiescence from Hen 3 with XMM-Newton.  Spectrum fitting with an absorbed one-temperature plasma or an absorbed BB.  Did not detect Hen 3 during the short Swift exposure.  Neither periodic or aperiodic X-ray nor UV variability were found  XMM-Newton data suggest that interaction of the residual jet with the ISM might survive for a long time after outbursts and might be responsible for the observed X-ray emission during quiescence.  Additional data are strongly needed to confirm these suggestions.

1305.3276
Hybrid cosmological simulations with stream velocities
Richardson, Scannapieco, Thacker

Relative "stream" velocities between the gas and DM arise due to radiation pressure and persist after recombination.  High-res AMR cosmo sims, which use SPH datasets as initial conditions; resolves 100 Msun mass, focus on 1e6 Msun mini-haloes at high z in which the first stars formed.  At z=17, the presence of stream velocities has only a minor effect on the number density of haloes below 1e6 Msun, but it greatly suppresses gas accretion onto all halos and the DM structures around them.  Stream velocities lead to significantly lower halo gas fractions, especially for ~1e5 Msun objects, and effect that is likely to depend on the orientation of a halo's accretion lanes.  This reduction in gas density leads to colder, more compact radial profiles, and it substantially delays the redshift of collapse of the largest haloes, leading to delayed star formation and possibly delayed reionization.  These many differences suggest that future simulations of early cosmological structure formation should include stream velocities to properly predict gas evolution, SF, and the epoch of reionization.

1305.3277
Discovery of an intermediate mass black hole at the center of the starburst/Seyfert composite galay IRAS 01072+4954
Valencia-S.

As the title says.

1305.3286
Scaling relations for galaxy clusters: properties and evolution
Giodini, .. Reiprich, Hoekstra, et al

[Review paper.]  Need well-calibrated scaling relations between observables and the total masses of clusters, to understand the physical processes that give rise to these relations.  They are also a critical ingredient for studies that aim to constrain cosmological parameters using galaxy clusters.  For this reason, much effort has been spent during the last decade to better understand and interpret relations of the properties of the ICM.  Improved X-ray data have expanded the mass range down to galaxy groups, whereas SZ surveys have opened a new observational window on the ICM.  In addition, continued progress in the performance of cosmological sims has allowed a better understanding of the physical processes and selection effects affecting the observed scaling relations.  Here we review the recent literature on various scaling relations, focussing on the latest observational measurements and the progress in the understanding of the deviations from self similarity.  

1305.3348
Full-sky formulae for weak lensing power spectra from total angular momentum method
Yamauchi, Namikawa, Taruya

Systematically derive full-sky formulae for the WL PS generated by scalar, vector and tensor perturbations from the total angular momentum (TAM) method.  Based on both the geodesic and geodesic deviation equations, first give the gauge-invariant expressions for the deflection angle and Jacobi map as observables of the CMB lensing and cosmic shear experiments.  Then apply the TAM method, originally developed in theoretical studies of CMB, to a systematic derivation of the angular power spectra.  The TAM representation, which characterizes the total angular dependence of the spatial modes projected along the LoS, can carry all the information of the lensing modes generated by scalar, vector, and tensor metric perturbations.  This greatly simplifies the calculation, and present a complete set of the full-sky formulae for angular PS in both the E-/B-mode cosmic shear and gradient-/curl-mode lensing potential of deflection angle.  Based on the formulae, give illustrative examples of non-vanishing B-mode cosmic shear and curl-mode of deflection angle in the presence of the vector and tensor perturbations, and explicitly compute the PS.

1305.3436
The progenitor of supernova 2011dh has vanished
Van Dyk, ... Filippenko, Cenko, Smith, .... Ganeshalingam et al

Observation at age ~641 days after SN type IIb show that the yellow supergiant star, clearly detected in pre-SN HST images, has disappeared, implying that this star was almost certainly the progenitor of the SN, hence ruling out compact progenitor and the yellow supergiant survival.  Also present ground-based UBVRI light curves obtained with KAIT up to SN age ~70 days.  From the light-curve shape including the very late-time HST data, and from recent interacting binary models for SN 2011dh, estimate that a putative surviving companion star to the now deceased yellow supergiant could be detectable by late 2013, especially in the UV.

1305.3516
Testing MOND with galaxy-galaxy gravitational lensing
Milgrom

As the title says.  [Why did you vote for this, E?!]  Compare MOND predictions with recent results of gg lensing, and find agreement on all counts, through MOND's phi(R) lensing signal generation (due solely to baryons).

1305.3576
WFC3 grism confirmation of the distant cluster Cl J1449+0856 at z=2.00: Quiescent and star-forming galaxy populations
Gobat ... Finoguenov, et al

Spectroscopically confirm 10 early-type galaxies in the field up to z~3, 5 of which in the cluster core; first direct spectroscopic confirmation of passive galaxies in a z=2 cluster environment.  140 redshifts in a 6 arcmin^2 field, trace the spatial and redshift galaxy distribution in the cluster core and background field.  Find two strong peaks at z=2.00 and 2.07, where only one was seen in the previously published ground-based data.  Now the cluster redshift is re-evaluated at z=2.00, with the background overdensity being revealed to be sparse and "sheet"-like.  ...

1305.3577
Galaxy evolution in overdense environments at high redshift: passive early-type galaxies in a cluster at redshift 2
Strazzullo, et al

[Related to the paper above]  Investigate stellar populations and morphological structure of cluster galaxies over an area of ~0.7Mpc^2 around the cluster core.  The cluster stands out as a clear overdensity both in redshift space, and in the spatial distribution of galaxies close to the center of the extended X-ray emission.  The cluster core region (r<200 kpc) shows a clearly enhanced passive fraction with respect to field levels.  However, together with a population of massive passive galaxies mostly with early-type morphologies, it also hosts massive actively star-forming, often highly dust-reddened sources.  Close to the cluster center, a multi-component system of passive and SF galaxies could be the future BCG still assembling.  Observe a clear correlation between passive stellar populations and an early-type morphology, in agreement with field studies at similar redshift.  Passive early-type galaxies in this cluster are typically a factor 2-3 smaller than similarly massive early-types at z~0, but also on average larger by a factor ~2 than their field analogs at z~2, lending support to recent claims of an accelerated structural evolution in high-redshift dense environments.  These results point towards the early formation of a population of massive galaxies, already evolved both in their structure and stellar populations, coexisting with still-actively forming massive galaxies in the central regions of young clusters 10 billion years ago.

Day 432

Saturday.  Sunday.  Monday.

1305.2413
Ultra-faint Ultravioldet galaxies at z~2 behind the lensing cluster Abell 1689: the luminosity function, dust extinction and star formation rate density
Alavi, et al

HST UV (F275W/F336W) imaging, used to identify z~2 SF galaxies via their Lyman break.  Detect galaxies 100x fainter than previous surveys at this redshift.  After removing multiple images, there are 58 galaxies between -19.5<M_UV<-13.  Determine effective volume by calculating the intrinsic sensitivity of the observations as a function of source plane position (possible because Abell 1689 mass distribution is well constrained).  Faint-end slope of LF is alpha=-1.56pm0.13, somewhat shallower than z>3.  No turnover in the LF down to MUV=-13. Increasingly redder UV spectral slopes with L observed at higher redshifts, but with redder slopes at all L and average reddening of <E(B-V)>=0.15.  Assume the stars in these galaxies are metal poor (0.2 Z_sun) compared to their brighter counterparts (Z_sun), resulting in bluer assumed intrinsic UV slopes and larger derived dust extinction.  The total UV L density at z~2 is 4.3e26 erg/s/Hz/Mpc^3, 80% of which is emitted by galaxies in the L range of this sample.  Determine the SFR density from UV-selected galaxies at z~2 (assuming constant dust extinction correction of 4.2 over all luminosities and a Kroupa IMF) of 0.147 M_sun/yr/Mpc^3, significantly higher than previous determinations because of the additional fainter galaxies and the larger dust correction factors.

1305.2418
Modified gravity-GADGET: a new code for cosmological hydrodynamical simulations of modified gravity models
Puchwein, Baldi, Springel

New code with modified gravity models presented (N-body & cosmo hydro sims).  Employs multigrid-accelerated Newton-Gauss-Seidel relaxation solver on an adaptive mesh to efficiently solve for perturbations in the scalar degree of freedom of the modified gravity model.  It is a new algorithm for P-Gadget3 code; can at the same time follow the baryonic physics included in P-Gadget3 (hydrodynamics, radiative cooling and star formation).  Demonstrate that the code works reliably by comparison with analytical results of simple cases, and by comparing cosmo sims to results from the literature.  Perform non-radiative and radiative cosmo hydro sims of f(R)-gravity model; also discuss the impact of AGN feedback on the matter PS, as well as degeneracies between the influence of baryonic processes and modifications of gravity.

1305.2420
Abell 2142 at large scales: an extreme case for sloshing?
Rossetti et al

Has multiple cold fronts, discovery of a new cold front at ~1 Mpc from the center.  Residual images, thermodynamics and metal abundance maps are qualitatively in agreement with predictions from numerical simulations of the sloshing phenomenon, but at larger scales.  Sloshing not confined to cores, but extends cluster-wide, extending well beyond the cooling region involving a large fraction of the ICM up to almost half of the virial radius.  Absence of a cool core and a newly discovered giant radio halo in A2142, in spite of its relaxed X-ray morphology, suggest that large scale sloshing, or the intermediate merger which caused it, may trigger Mpc-scale radio emission and may lead to the disruption of the cluster cool core.

1305.2430
The structure of the Milky Way's hot gas halo
Miller, Bregman

Use LoS to 26 AGN, 1 LMC source and 2 galactic sources to find OVII Ka absorption to measure 1e6K gaseous halo around the MW.  Beta model fit shows hot gas accounts for 10-50% of the missing baryons in the MW.  Find Z>~0.2 Z_sun metallicity based on pulsar dispersion measure towards the LMC.

1305.2542
Magnetic fields of neutron stars
Reisenegger

NSs contain the strongest B-fields known in the Universe.  Discuss briefly how these B-fields are inferred from observations, as well as the evidence for their time-evolution.  Show: how these extremely strong fields are actually weak in terms of their effects on the stellar structure, as is also the case for magnetic stars on the upper MS and magnetic WDs, which have similar total magnetic fluxes.  Propose a scenario in which a stable hydromagnetic equilibrium (containing a poloidal and toroidal field component) is established soon after the birth of the NS, aided by the strong compositional stratification of NS matter, and this state is slowly eroded by a non-ideal magneto-hydrodynamic processes such as beta decays and ambipolar diffusion in the core of the star and Hall drift and breaking of the solid in its crust.  Over sufficiently long timescales, the fluid in the NS core will behave as if it were barotropic [i.e., density is only a function of pressure (and vice versa)], because, depending on temperature and magnetic field strength, beta decays will keep adjusting the composition to the chemical equilibrium state, or ambipolar diffusion will decouple the charged component from the neutrons.  Therefore, the still open question regarding stable hydromagnetic equilibria in barotropic fluids will become relevant for the evolution, at least for "magnetar" fields, too strong to be stabilized by the solid crust.

1305.2619
Dark matter distributions around massive black holes: a general relativistic analysis
Sadeghian, Ferrer, Will

The CDM at the center of a galaxy will be redistributed by the presence of a massive BH.  The redistribution may be determined using an approach pioneered by Gondolo and Silk: begin with a model distribution function for the DM, and "grow" the BH adiabatically, holding the adiabatic invariants of the motion constant.  Unlike the approach of G&S, which adopted Newtonian theory together with ad hoc correction factors to mimic GR effects, carry out the calculation fully relativistically, using the exact Schwarzschild geometry of the BH.  Find that the density of DM generically vanishes at r=2R_S, not 4R_S as found by G&S, where R_S is the Schwarzschild radius, and that the spike very close to the BH reaches significantly higher densities.  Apply the relativistic adiabatic growth framework to obtain the final DM density for both cored and cusped initial distributions.  Besides the implications of these results for indirect detection estimates, show that the gravitational effects of such a DM spike are significantly smaller than the relativistic effects of the BH, including frame dragging and quadrupolar effects, for stars orbiting close to the BH that might be candidates for testing the BH no-hair theorems.

1305.2628
An overview of the dwarf galaxy survey
Madden, et al

DGS is a 230h program of FIR and submm photometric and spectroscopic observations of Herschel which trace dust, gas and stars of a sample of 50 galaxies (selected with largest metallicity range achievable in the local universe) and span 4 orders of magnitude in SFR.  Designed to get a handle on the physics of the ISM of low metallicity dwarf galaxies, especially on their dust and gas properties and the ISM heating and cooling processes.  Gas cooling in neutral and ionized phases also studied.  Describe the sample selection and global properties of the galaxies, the observing strategy, as well as the vast ancillary database available to complement the Herschel observations.  Full DGS survey's scientific potential described.

1305.3130
HERschel Observations of Edge-on Spirals (HEROES). I: Far-infrared morphology and dust mass determination
Verstappen et al

Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them.  HEROS set up to observe a sample of 7 large edge-on galaxies across various wavelengths for this investigation.  Determine horizontal and vertical profiles from Herschel observations of the galaxies in the sample and describe the morphology.  Modified BB fits to the global fluxes, measured using aperture photometry, result in dust temperatures and dust masses.  The latter values are compared to these that are derived from radiative transfer models taken from the literature.  On the whole, the Herschel flux measurements agree well with archival values.  Find that the exponential horizontal dust distribution model often used in the literature generally provides a good description of the observed horizontal profiles.  Three out of the 7 galaxies show signatures of extended vertical emission at 100 and 160 um at the 5 sigma level, but in two of these it is probably due to deviations from an exactly edge-on orientation.  Only for NGC 4013, a galaxy in which vertically extended dust has already been detected in optical images, we can detect vertically extended dust, and the derived scale height agrees with the value estimated through radiative transfer modeling.  Analysis hints at a correlation between the dust scale height and its degree of clumpiness, which we infer from the difference between the dust masses as calculated from modeling of optical data and from fitting the spectral energy distribution of Herschel datapoints.

Day 431

Thursday.  Friday.

1305.2222
STIS Coronagraphic imaging of Fomalhaut: Main belt structure and the orbit of Fomalhaut b
Kalas, Graham, Fitzgerald, Clampin

Observed Fomalhaut b is recovered with optical coronagraph with HST; tenuous nebulosity beyond the main dust belt detected to at least 209 AU and a ~50 AU wide azimuthal gap north of Fom b.  Fom b appears elliptical in STIS detection.  Orbit of Fom b is highly eccentric with e=0.8, a=177 pm68 AU and q=32 pm24 AU.  Fom b apsidally aligned with the belt and 90% of allowed orbits (from MCMC) have mutual inclination 36 deg or less.  Fom b's orbit is belt-crossing in projection, but only 12% of possible orbits have nodes ithin a 25 AU wide belt annulus.  The high e invokes a dynamical history where Fom b may have experienced a significant dynamical interaction with a hypothetical planet Fom c, and the current orbital configuration may be relatively short-lived.  Any weakly bound satellite system surrounding a planet would be sheared and dynamically heated at periapse.  Argue that Fom b's minimum mass is that of a dwarf planet in order for a circumplanetary satellite system to remain bound to a sufficient radius from the planet to be consistent with the dust scattered light hypothesis.  Fom b may be optically bright because the recent passage through periapse and/or the ascending node has increased the erosion rates of planetary satellites.  In the coplanar case, Fom b will collite with the main belt around 2032, and the subsequent emergent phenomena may help determine its physical nature.

1305.2267

Bimodality of galaxy disk central surface brightness distribution in the Spitzer 3.6 micron band
Source, Courtois, Sheth, Tully

Disk central surface brightnesses (mu0) at 3.6 um for 438 galaxies (distance and absolute magnitude cutoffs) from a MIR survey S4G (Spitzer Survey of Stellar Structure in Galaxies).  Demonstrate that there is a bimodality in the distribution of mu0.  Investigate caveats (small number statistics, knowledge of the environmental influences, biases from low S/N or corrections for galaxy inclination).  Analyses show that the bimodal distribution of mu0 cannot be due to any of these.  Two modes: DM dominated mode where the DM dominates at all radii (low SB galaxies) and baryonic matter dominated mode (baryons dominate the DM in the central parts), giving rides to high SB disks.  Lack of intermediate SB suggests that galaxies avoid a mode where DM and baryons are co-dominant in the central parts of galaxies.

1305.2297
Dependence of low redshift Type Ia supernovae luminosities on host galaxies
Liang, Wang

SNIa in high L hosts are brighter after light-curve correction, at 3 sigma CL.  Also find: SNIa in large galaxies are brighter after correction at 2 sig.  Demonstrate that the residual linearly depends on host L at a confidence of 4 sig or host size at 3.3sig CL.

Day 430

Monday.  Tuesday.  Wednesday.  Euclid meeting at Leiden.

1305.2195
Following the flow: tracer particles in astrophysical fluid simulations
Genel, Vogelsberger, ... Springel, Hernquist

Present two independent numerical schemes for passive tracer particles in the hydrodynamical moving-mesh code Arepo, and compare their performance for various problems, from simple tests to cosmological simulations.  Purpose of tracer particles: allow the flow to be followed in a Lagrangian way, reliably tracing the evolution of the fluid; subsequently measure local instantaneous fluid property, thereby recording the thermodynamical hisotry of individual fluid parcels.  "Velocity field tracers": advected according to the local velocity field of the fluid; find that such tracers do not in general follow the mass flow correctly (particularly complex flows).  Discuss a novel implementation of "Monte Carlo tracers" which are moved along with fluid cells, and are exchanged probabilistically between them following the mass flux.  This method reproduces the mass distribution of the fuild correctly by construction, but is more diffusive than the fluid itself.  Show that this novel approach is more reliable and is appropriate for following hydrodynamical flows in mesh-based codes.  The MC tracers can also naturally be transferred between fluid cells and other types of particles, such as stellar particles, so that the mass flow in cosmological simulations can be followed in its entirety.  Demonstrate a possible use of the tracer particles by studying the thermodynamical history of the halo atmosphere in the Santa Barbara Cluster [?].

1305.2199
The most luminous quasars do not live in the most massive dark matter haloes at any redshift
Fanidakis, Maccio, Baugh, Lacey, Frenk

In contrast to expectation, in a galaxy formation model which includes AGN feedback, quasars are predicted to live in average DM halo environments with typical masses of a few times 1e12 Msun.  This fundamental prediction arises from the fact that quasar activity (BH accretion with luminosity greater than 1e46 erg/sec) is inhibited in DM haloes where AGN feedback operates.  The galaxy hosts of quasars in simulations are identified with over massive (in gas and stars) spheroidal galaxies, in which BH accretion is triggered via a galaxy merger or secular processes.  Further show that the z=0 descendants of high redshift (z~6) QSOs span a wide range of morphologies, galaxy and halo masses.  The z~6 BHs typically grow only by a modest factor by the present day.  High z QSOs never inhabit the largest DM haloes at that time and their descendants are very seldom found in the most massive haloes at z=0.  [Is this compatible with observations?]  Also show that observationally it is very likely to find an enhancement in the abundance of galaxies around quasars at z~5.  However, these enhancements are considerably weaker compared to the overdensities expected at the extreme peaks of the DM distribution.  Thus, it is very unlikely that a quasar detected in the z>5 Universe pinpoints the location of the progenitors of superclusters in the local Universe.

1305.2200
Constraints on black hole fuelling modes from the clustering of X-ray AGN
Fanidakis, et al

Clustering analysis of X-ray selected AGN by compiling X-ray samples from the literature and re-estimating the DM halo masses of AGN in a uniform manner.  Find: moderate luminosity AGN (1e42-44 erg/sec) in the z=0-1.3 Universe are typically found in DM haloes with mases of 1e13 Msun.  Compare to theoretical predictions of the coupled galaxy and BH formation model GALFORM.  Find good agreement when calculation includes the hot-halo mode of accretion onto the central BH.  This type of accretion, which is additional to the common cold accretion during disk instabilities and galaxy mergers, is tightly coupled to the AGN feedback in the model.  The hot-halo mode becomes prominent in DM haloes with masses greater than 1e12.5 Msun, where AGN feedback typically operates, giving rise to a distinct class of moderate luminosity AGN that inhabit rich clusters and superclusters.  Cold gas fueling of the BH cannot produce the observationally inferred DM halo masses of X-ray AGN.  Switching off AGN feedback in the model results in a large population of luminous quasars (>1e44 erg/sec) in DM haloes with masses up to 1d14 Msun, which is inconsistent with the observed clustering of quasars.  The abundance of hot-halo AGN decreases significantly in the z~3-4 universe.  At such high redshifts, the cold accretion mode is solely responsible for shaping the environment of moderate luminosity AGN.  Analysis supports two accretion modes (cold and hot) for the fueling of supermassive BHs and strongly underlines the importance of AGN feedback in cosmological models both of galaxy formation and BH growth.  

1305.2194
Galileon forces in the solar system
Andrews, Chu, Trodden

Obtain an analytic understanding of realistic astrophysical dynamics in the presence of a Vainshtein screened fifth force arising from IR modifications of GR.  Attempt to solve (general flat spacetime galileon model) the scalar force law between well separated bodies located well within the Vainshtein radius of the Sun.  Derive the exact static Green's function of the galileon wave equation linearized about the background field generated by the Sun, for the minimal cubic and maximally quartic galileon theories, and then introduce a method to compute the general leading order force law perturbatively away from these limits.  Also show that the same NLs which produce the V screening effect present obstacles to an analytic calculation of the galileon forces between closely bound systems within the SS, such as that of the Earth and Moon.  Within the test mass approximation, deduce that a large enough quartic gaileon interaction would suppress the effect on planetary perihelion precession below the level detectable by even the next-generation experiments.

1305.2198
Oscillations and stability of polytropic filaments
Breysse, Kamionkowski, Benson

Study the oscillations and stability of self-gravitating cylindrically symmetric fluid systems and collisionless systems.  Study small perturbations to the equilibrium system and find the normal modes, using methods similar to those used in astroseismology.  Find that there is a single sequence of purely radial modes that become unstable if the adiabatic exponent is less than 1.  Nonradial modes can be divided into p modes, which are stable and pressure-driven, and g modes, which are gravity driven.  The g modes become unstable if the adiabatic exponent is greater than the polytrope index [?].  These modes are analogous to the modes of a spherical star, but their behavior is somewhat different because a cylindrical geometry has less symmetry than a spherical geometry.  This implies that perturbations are classified by a radial quantum number, an azimuthal quantum number, and wavelength in the z direction, which can become arbitrarily large.  Find that decreasing this wavelength increases the frequency of stable modes and increases the growth rate of unstable modes.  Use variational arguments to demonstrate that filaments of collisionless matter with ergodic distribution [?] functions are stable to purely radial perturbations, and that filaments with ergodic power-law distribution functions are stable to all perturbations.

1305.2204
The redshift and mass dependence on the formation of the Hubble sequence at z>1 from CANDELS/UDS
Mortlock, ... et al

Sample of 1188 massive galaxies with M*>1e10 Msun between 1<z<3 within UDS of CANDELS field; study structures and morphologies.  Using this sample, determine how galaxy structure and morphology evolve with time.  Visually classify sample into disks, ellipticals and peculiar systems and correct for z effects on the classifications through simulations.  Find evolution in the fractions of galaxies at a given visual classification as a function of z.  The peculiar population is dominant at z>2 with a substantial spheroid population, and a negligible disk population.  [spheroid is elliptical?]  Compute the transition redshift, z_trans, where the combined fraction of spheroids and disks is equal to that of peculiar galaxies, at z_trans=1.86 pm 0.62 for galaxies in the sample's stellar mass range.  Find that this changes as a function of stellar mass, with Hubble-type systems becoming dominant at higher redshifts for higher mass galaxies (z_trans=2.2 pm 0.82), rather than for the lower mass galaxies (z_trans=1.73 pm 0.57).  Higher mass galaxies become morphologically settled before their lower mass counterparts, a form of morphological downsizing.  Compre visual classifications with Sersic index, the concentration, asymmetry and clumpiness (CAS) parameters, SFR and rest frame U-B color.  Find links between the color of a galaxy, its star formation rate and how extended or peculiar it appears.  Finally, discuss the negligible z>2 disk fraction based on visual morphologies and speculate that this is an effect of forming disks appearing peculiar through processes such as violent disk instabilities or mergers.  Conclude that to properly define high z morphology, a new and more exact classification scheme is needed.