Day 574

Thursday.

1312.5981
Weak gravitational lensing
Hoekstra

Lecture notes on gravitational lensing.

1312.6318
The Atlas3D project -- XXXVII. Cold gas and the colors and ages of early-type galaxies
Young et al

Early-type (elliptical and lenticular) galaxies are not as gas-poor as previously thought, and at least 40% of local early-type galaxies are now known to contain molecular and/or atomic gas.  This cold gas offers the opportunity to study recent galaxy evolution through the processes of cold gas acquisition, consumption (SF), and removal.  Molecular and atomic gas detection rates range from 10% to 34% in red sequence early-type galaxies, depending on how the red sequence is defined, and from 50% to 70% in blue early-type galaxies.  Massive red sequence early-type galaxies (M*>5e10 Msun derived from dynamical models [how?]) are found to have HI masses up to M(HI)/M* ~ 0.06 and H2 masses up to M(H2)/M*~0.01.  Some 20% of all massive early-type galaxies may have retained atomic and/or molecular gas through their transition to the red sequence.  However, kinematic and metallicity signatures of external gas accretion (either from satellite galaxies or the IGM) are also common, particularly at M*<=5e10 Msun, where such signatures are found in ~50% of H2-rich early-type galaxies.  Data are thus consistent with a scenario in which fast rotator early-type galaxies are quenched former spiral galaxies with have undergone some bulge growth processes, and in addition, some of them also experience cold gas accretion which can initiate a period of modest SF activity.  Discuss implications for the interpretation of color-magnitude diagrams.

1312.6330
Detecting ancient supernovae at z~5-12 with CLASH
Whalen, Smidt, Johnson, Holz, Stiavelli, Fryer

Possible with JWST, WFIRST and next generation of extremely large telescopes.  SL by massive clusters, like those in CLASH, could reveal such events now by magnifying their flux by factors of 10 or more.  Find that CLASH will likely discover at least 2-3 core-collapse SNe at 5<z<12 and perhaps as many as ten.  Future surveys of cluster lenses similar in scope to CLASH by the JWST might find hundreds out to z~15-17.  Besides revealing the masses of early stars, these ancient SNe will also constrain cosmic SFRs in the era of first galaxy formation.

1312.6645
Evidence for gravitational lensing of the cosmic microwave background polarization from cross-correlation with the cosmic infrared background
POLARBEAR collaboration, et al

As the title says: 4.0 sigma evidence; presence of a lensing B-mode at 2.3 sigma.  Demonstrate that results are not biased by instrumental and astrophysical systematic errors by performing null-tests, checks with simulated and real data, and analytical calculations.  This measurement of polarization lensing, made via the robust cross-correlation channel, not only reinforces POLARBEAR auto-correlation measurements, but also represents one of the early steps towards establishing CMB polarization lensing as a new probe of cosmology and astrophysics.

1312.6692
Generalized microlensing effective timescale
Gould [!!]

Microlensing effective timescale t_eff=beta*t_E is used frequently in high-magnification (beta <<1) microlensing events, because it is better constrained than either the impact parameter beta or the einstein timescale t_E separately.  It also facilitates intuitive understanding of light curves prior to determination of a model.  Similar considerations may apply to very low magnification events.  Therefore, provide a generalization of this quantity to all events: t_eff = beta * t_E * sqrt((1+beta^2/2)(1+beta^2/4)).  

1312.6693
Astrophysics source code library: Incite to Cite!
DuPrie et al

ASCL: http://ascl.net: online registry of >700 source codes that are of interest to astrophysicists, with more being added regularly.  Description of ASCL.

1312.6694
Constraining sub-parsec binary supermassive black holes in quasars with multi-epoch spectroscopy.  II.  The population with kinematically offset board Balmer emission lines
Liu, Shen, Bian, Loeb, Tremaine

A small fraction of quasars have long been known to show bulk velocity offsets in the broad Balmer lines wrt the systemic redshift of the host galaxy.  Models to explain these offsets usually invoke broad line region gas kinematics/asymmetry around single BHs, orbital motion of massive (~sub-pc) binary BHs (BBHs), or recoil BHs, but single-epoch spectra are unable to distinguish between these scenarios.  The LoS radial velocity shifts from long-term spectroscopic monitoring can be used to test the BBH hypothesis.  Select a sample of 399 quasars with offset broad H-beta lines from the SDSS DR7 quasar catalog, and have conducted second-epoch optical spectroscopy for 50 of them.  Combined wit hthe existing SDSS spectra, the new observations enable LOS RV shift constraint on broad H-beta lines with a rest-frame baseline of a few years to nearly a decade.  Using cross-correlation analysis, detect (99% CL) radial accelerations in the broad H-beta lines in 24/50 objects.  Suggest that 9/24 detections are sub-pc BBH candidates, which show consistent velocity shifts independently measured from a second broad line (either H-alpha or Mg II) without significant changes in the broad line profiles.  Combining the results on the general quasar population studied in Paper I, find a tentative anti-correlation between the velocity offset in the first-epoch spectrum and the average acceleration between two epochs, which could be explained by orbital phase modulation when the time separation between two epochs is a non-negligible fraction of the orbital period of the motion causing the line displacement.  DIscuss the implications of results for the identification of sub-pc BBH candidates in offset-line quasars and for the constraints on their frequency and orbital parameters.

1312.6698
Observational evidence for black holes
Narayan, McClintock

Two populations of BHs: (i) stellar mass (5-30 Msun), millions present in each galaxy, and (ii) SMBHs (1e6-10 Msun), one each in the nucleus of every galaxy.  Strong circumstantial evidence that these are true BHs with even horizons.  SMBH masses strongly correlated with properties of their host galaxies, suggesting that these black holes have strong influence on the formation and evolution of entire galaxies.  Spin parameters have recently been measured for a handful of BHs.  Indication that the kinetic power of at least one class of relativistic jet ejected from accreting BHs may be correlated with BH spin.  If verified, it would suggest that these jets are powered by a generalized Penrose process mediated by B-fields.

1312.6135
Jellyfish: evidence of extreme ram-pressure stripping in massive galaxy clusters
Ebeling, Stephenson, Edge

A jellyfish-like (ram-pressure stripping: shock compressed and then removed from galaxies falling into the cluster) galaxy, can be bright enough to outshine the BCG.

1312.7297
New method to measure proper motions of microlensed sources: Application to candidate free-floating-planet event MOA-2011-BLG-262
Skowron, … Gould, et al

Take advantage of the fact that the source position is known from the event itself  Apply to a system of high proper (relative) motion of 20mas/yr or 12 mas/yr (depending on the model).  Characteristics imply that the lens could be a brown dwarf or a massive planet with a roughly Earth-mass "moon".  

1312.7619
Inflationary paradigm after Planck 2013
Guth, Kaiser, Nomura

"Cosmic inflation is on a stronger footing than ever before."

1312.7877
Self-calibration of BICEP1 three-year data and constraints on astrophysical polarization rotation
Kaufman et al

B-mode CMB signature from inflationary gravitational waves; also have the potential to constrain cosmic birefringence [?], which would produce non-zero expectation values for the CMB's TB and EB spectra.  However, instrumental systematic effects can also cause these TB and EB correlations to be non-zero (overall miscalibration of the polarization orientation of the detectors; also produces small bias in the BB spectrum).  Revise estimate of systematic error on the polarization rotation angle from the two-year analysis by comparing multiple calibration methods.  Investigate the polarization oration for the 100 GHz and 150 GHz separately to investigate theoretical models that produce frequency-denendent cosmic birefringence.  Find no evidence in the data supporting either these models or Faraday rotation of the CMB polarization by the MW's B-field.  Assuming that there is no cosmic birefringence, can use the TB and EB spectra to calibrate detector polarization orations, thus reducing bias of the cosmological B-mode spectrum from leaked E-modes due to possible polarization orientation miscalibration.  After applying this "self-calibration" process, find that the upper limit on the tensor-to-scalar ratio decreases slightly, from r<0.70 to r<0.65 at 95% CL.

1401.0046
Dark Energy: A short review
Mortonson, Weinberg, White

Briefly summarize theories for the origin of cosmic acceleration and the observational methods being used to test these theories.  Discuss current observational state of the field, with constraints from CMB, BAO, SN Ia, direct measurements of H0, and measurements of galaxy and matter clustering.  Assuming a flat universe and DE with a constant EoS parameter w = P/rho, the combination of Planck CMB T anisotropies, WMAP CMB polarization, Union2.1 SN compilation, and a compilation of BAO measurements yields w=-1.10pm0.08, consistent with a cosmological constant w=-1.  However, with these constraints the cosmological constant model predicts a value of H0 that is lower than several of the leading recent estimates, and it predicts a parameter combination sigma8 Omega_m^0.5 that is higher than many estimates from WL, galaxy clusters, and z-space distortions.  Individually these tensions are only significant at the 2 sigma level, but they arise in multiple data sets with independent statistics and distinct sources of systematic uncertainty.  The tensions are stronger with Planck CMB data than they were with WMAP because of the smaller statistical errors and the higher central value of Omega_m.  Wit hthe improved measurements expected from the next generation of data sets, these tensions may diminish, or they may sharpen in a way that points towards a more complete physical understanding of cosmic acceleration.

1401.0197
A new hybrid framework to efficiently model lines of sight to gravitational lenses
McCully, Keeton, Wong, Zabludoff

SL systems affected by other mass long the LoS; shear and convergence can be used to approximate the contributions from objects projected far from the lens, but higher-order effects need to be included for objects that are closer.  Develop a framework for multi-plane lensing that can handle arbitrary combination of planes treated with shear and convergence and planes treated exactly (including higher order terms).  This framework addresses all of the traditional lensing observables including image positions, fluxes, and time delays to facilitate lens modeling that incudes LoS effects.  It balances accuracy with efficiency.  Identify a generalized multi-plane mass sheet degeneracy in which the effective shear and convergence are sums over the lensing planes with specific, redshift-dependent weighting factors.

1401.0385
Super-sample covariance in simulations
Li, Hu, Takada

Using separate universe simulations, accurately quantify super-sample covariance (SSC), type typically dominant sampling error for matter PS estimators in a finite volume, which arises from the presence of super survey modes.  By quantifying the PS response to BG mode, this approach automatically captures the separate effects of beat coupling in the quasilinear regime, halo sample variance in the NL regime and a new dilation effect which changes scales in the PS coherently across the survey volume, including the BAO scale.  It models these effects at typically the few percent level or better with a handful of small volume simulations for any survey geometry compared with directly using many thousands of survey volumes in a suite of large volume simulations.  The stochasticity of the response is sufficiently small that in the quasilinear regime, SSC can be alternately included by fitting the mean density in the volume with these fixed templates in parameter estimation.  Also test the halo model prescription and find agreement typically at better than the 10% level for the response.  

1401.0392
Galaxy-wide outflows: cold gas and star formation at high speeds
Zubovas, King

Several active galaxies show strong evidence for fast (~1000 km/s) massive (dot M=1e3 Msun/yr) gas outflows.  Such outflows are expected on theoretical grounds once the central SMBH reaches the mass set by the M-sigma relation, and may be what makes galaxies become red and dead.  Despite their high velocities (imply T far above those necessary for molecule dissociation) the outflows contain large amounts of molecular gas.  To understand this surprising result, investigate the gas cooling and show that the outflows cannot stably persist in high-T states.  Instead the outflowing gas forms a two-phase medium, with cold dense molecular clumps mixed with hot tenuous gas, as observed.  Also show that efficient cooling leads to SF, providing an observable outflow signature.  The central parts of the outflows can be intrinsically luminous gamma-ray sources, provided that the central BH is still strongly accreting.  Note also that these outflows can persist for ~1e8 yr after the central AGN has turned off, so that many observed outflows (particularly with high speeds) otherwise assumed to be driven by starbursts might also be of this type.

1401.0484
Parallax beyond a kilo parsec from spatially scanning the wide field camera 3 on the Hubble space telescope
Riess, … Filippenko, et al

Use spatial scanning (a newly developed observing mode on HST and WFC3) to increase source sampling 1000x and measure changes in source positions to a precision of 20-40 microarcseconds, more than an order of magnitude better than attainable in pointed observations.  This observing mode can usefully measure the parallaxes of bright stars at distances of up to 5 kpc, a factor of 10 farther than achieved thus far with HST.  Long-period classical Cepheid variable stars in the MW, nearly all of which reside beyond 1kpc, are especially compelling targets for parallax measurements from scanning ,as they may be used to anchor determination of the Hubble constant to ~1%.  Illustrate the method by measuring to high precision the parallax of a classical Cepheid, SY Aurigae, at a distance of >2kpc, using 5 epochs of spatial-scan data obtained at intervals of 6 months.  Rapid spatial scans also enable photometric measurements of bright MW Cepheids---which would otherwise saturate even in the shorted possible pointed observations --- on the same flux scale as extragalactic Cepheids, which is a necessity for reducing a leading source of systematic error in the Hubble constant.  Demonstrate this capability with photometric measurements of SY Aur on the same system used for Cephids in Type Ia SN host galaxies.  While the technique and results presented here are preliminary, an ongoing program with HST is collecting such parallax measurements for another 18 Cepheids to produce a better anchor for the distance scale.