Day 571

1312.4530
The power of the three-point correlation function: disentangling interacting dark energy cosmologies and estimating the halo bias
Moresco et al

Investigate the possibility of constraining coupled dark energy (cDE) cosmologies using the 3pt correlation function (3PCF).  Use simulation to study statistical properties of CDM halos in various models (LCDM & 5 models where DE and CDM interact).  Measure both 3PCF zeta(theta) and the reduced Q(theta) at 2<r [Mpc/h] < 40 and 0<z<2.  Q is flat at low z and small scales, but builds up the characteristic V-shape anisotropy at increasing redshifts and scales.  Compared to LCDM, cDE models show lower (higher) values of the halo 3PCF for perpendicular (elongated) configurations.  The effect is also scale-dependent, with differences between LCDM and cDE models that increase at large scales. Estimate the halo bias, results in fair agreement with that computed from 2PCF.  Find that these estimates are independent of the cosmology that is assumed to model the CDM component.  In particular, they do not depend on the value of sigma_8, allowing to break the bias-sigma8 degeneracy present in 2PCF.  This study demonstrates the power of a higher-order clustering analysis in discriminating between alternative cosmological scenarios, for both present and forthcoming galaxy surveys, such as BOSS and Euclid.

1312.4533
Satellite galaxies around present-day massive ellipticals
Ruiz, Trujillo, Mármol-Queraltó

Study the satellite distribution around ~1000 massive (M*>2e11 Msun) visually classified elliptical galaxies down to a satellite mass ratio of 1:400 (4e8<M_sat<2e11 Msun), from SDSS DR7.  Host galaxies selected to be representative of mass complete sample.  The satellites of these galaxies were searched within a projected radial distance of 100 kpc to their hosts.  Found that only 17-23% of the massive ellipticals has at least a satellite down to a mass ratio 1:10.  This number increases to 40-52% if satellites down to 1:100 are observed, and is >55-70% if going down further to 1:400.  The average projected radial distance of the satellites to their hosts is ~59 kpc (49-51 kpc if incompleteness accounted for).  The number of satellites per galaxy host only increases very mildly at decreasing the satellite mass.  The fraction of mass which is contained in the satellites down to a mass ratio of 1:400 is 7.4% of the total mass contained by the hosts.  Satellites with a mass ratio from 1:2 to 1:5 (with ~27% of the total mass of the satellites) are the main contributor to the total satellite mass.  If the satellites eventually infall into the host galaxies, the merger channel will be largely dominated by satellites with a mass ratio down to 1:10 (as these objects have 66% of the total mass in satellites).  

1312.4543
Fundamental mass-spin-morphology relation of spiral galaxies
Obreschkow, Glazebrook

Present high-precision measurements of the specific baryon angular momentum jb, contained in stars, atomic gas, and molecular gas, out to ~10 scale radii, in 16 nearby spiral galaxies of the THINGS sample.  The accuracy of these measurements improves on existing studies by more than an order of magnitude, leading to the discovery of a strong correlation between the baryon mass Mb, jb, and the bulge mass fraction B/T, fitted by B/T=-0.34pm0.03*log(jb/Mb/p1e-7 kpc km/s/Msun]) - (0.04pm0.01) on the full sample range of B/T=0.00-0.32 and Mb/Msun=1e9-1e11.  The corresponding relation for the stellar quantities Ms and Js is identical within the uncertainties.  These M-j-B/T relations likely originate from the proportionality between j/M and the surface density of the disk that dictates its stability against (pseudo-)bulge formation.  Using a CDM model can approximately explain classical scaling relations, such as the fundamental plane of spiral galaxies, the TF relation, and the mass-size relation, in terms of the M-j-B/T relation.  These results advocate the use of mass and angular momentum as the most fundamental quantities of spiral galaxies.

1312.4593
Halo masses of MgII absorbers at z\sim 0.5 from SDSS DR7
Gauthier et al

Present cross-correlation function of MgII absorbers with respect to a volume-limited sample of luminous red galaxies (LRGs) at z=0.45-0.60 using the largest MgII absorber sample and a new LRG sample from SDSS DR7.  Present clustering signals on projected scales r_p=0.3-35 Mpc/h in four Wr(2796) bins spanning Wr=0.4-5.6A.  Find that on average MgII absorbers reside in halos <log Mh>~12.1, similar to the halo mass of an L* galaxy.  Report that the weakest absorbers in the sample with W_r=0.4-1.1A reside in relatively massive haloes with <log Mh>~12.5, while stronger absorbers reside in halos of similar or lower masses ~11.6.  Compare bias b and the frequency distribution function of absorbers f_Wr with a simple model incorporating an isothermal density profile to mimic the distribution of absorbing gas in halos.  Also compare the bias with Tinker&Chen (2008) who developed HOD models of MgII absorbers that are constrained by b and f_Wr.  The simple isothermal model can be ruled [out] at ~2.8 sigma level mostly because of its inability to reproduce f_Wr.  However, bias is consistent with both models, including TC08.  In addition, show that the mean bias of absorbers does not decrease beyond Wr~1.6A.  The flat or potential upturn of b for Wr>~1.6 A absorbers suggests the presence of additional cool gas in massive halos.  

1312.4602
Very large array sky survey (VLASS) white paper: go deep, not wide
Hales

As the title says.  Wide will be covered by new breed of pre-SKA radio telescopes with improved surveying capabilities.

1312.4611
The clustering of galaxies in the SDSS-III braying oscillation spectroscopic survey: testing gravity with redshift-space distortions using the power spectrum multipoles
Beutler, Saito, Seo, … et al

BOSS CMASS DR11 sample (690k galaxies in 0.43<z<0.7 over 8.5k sq.deg): use a PS estimator, analyse the anisotropic clustering.  Measure the multipole PS in a self-consistent manner for the first time in the sense that they provide a proper way to treat the survey window function and the integral constraint, without the commonly used assumption of an isotropic PS and without the need to split the survey into sub-regions.  The main cosmological signals exploited in the analysis are BAO and the signal of z-space distortions, both of which are distorted by Alcock-Paczynski effect.  Together, these signals allow to constrain the distance ratio D_V/r_s=13.9pm0.2, the AP parameter = 0.68pm0.03, and the growth rate of structure f/sigma8=0.42pm0.04 at the effective redshift z_eff=0.57.  Combining dataset with Planck to test GR through the simple gamma-parameterization, where the growth rate is given by f(z)=Omega^gamma_m(z), reveals a ~2 sigma tension between the data and the prediction by GR.  The tension between the result and GR can be traced back to a tension in the clustering amplitude sigma8 between CMASS and Planck.

1312.4629
On physical scales of dark matter halos
Zemp

In general, the traditional way of characterizing sizes and masses of haloes (spherical over densities with respect to an evolving density threshold) dramatically overpredicts the degree of evolution in the last 10 Gyr, especially for low mass haloes.  This pseudo-eovlution is leading to the illusion of growth even though there are no major changes within fixed physical scales.  Such formal size definitions also surge as proxies for the vitalized region of a halo in the literature, but these spherical over density scales do not coincide with the virtualized region.  A physically more precise nomenclature would be to just characterize the by their very definition instead of calling such formal size and mass definitions 'virial'.  In general, find a discrepancy between the evolution of the underlying physical structure of dark matter haloes seen in cosmological structure formation simulations and pseudo-evolving formal virial quantities.  Question the importance of the role of formal virial quantities currently ubiquitously used in descriptions, models and relations that involve properties of DM structures.  Concepts and relations based on pseudo-evolving formal virial quantities do not properly reflect the actual evolution of DM haloes and lead to an inaccurate picture of the physical evolution of the Universe.

1312.4724
Supernovae in paired galaxies
Nazaryan, et al

Investigate the influence of close neighbor galaxies on the properties of SNe and their host galaxies using 56 SNe located in pairs of galaxies with different levels of SF and nuclear activity.  The mean distance of SNe II from nuclei of hosts is greater by about a factor of 2 than that of type Ibc SNe.  The distribution and mean distances of SNe are consistent with previous results compiled with the larger sample.  For the first time it is shown that SNe Ibc are located in paris with significantly smaller difference of radial velocities between components than pairs containing SNe Ia and II.  Consider this as a result of higher SFR of these closer systems of galaxies.

1312.4736
The Pan-STARRS1 medium-deep survey: The role of galaxy group environment in the star formation rate versus stellar mass relation and quiescent fraction out to $z \sim 0.8$
Lin et al

Present the sSFR-M* relation, as well as the quiescent fraction vs M* relation in different environments.  Confirm that the fraction of quiescent galaxies is strongly dependent on environment at a fixed stellar mass, but the amplitude and the slope of the SF sequence is similar between the field and groups: the sSFR-density relation at a fixed stellar mass is primarily driven by the change in the SF and quiescent fractions between different environments rather than a global suppression in the SFR for the SF population.  However, restricting the sample to cluster-scale environments (M>1e14 Msun), find a global reduction in the sSFR of the SF sequence of 17% at 4 sigma confidence as opposed to its field counterpart.  After removing the stellar mass dependence of the quiescent fraction seen in field galaxies, The excess in the quiescent fraction due to the environment quenching in groups and clusters is found to increase with stellar mass.  Argue that these results are in favor of galaxy mergers to be the primary environment quenching mechanism operating in galaxy groups whereas strangulation is able to reproduce the observed trend in the environment quenching efficiency and stellar mass relation seen in clusters.  Results also suggest that the relative importance between mass quenching and environment quenching depends on stellar mass -- the mass quenching plays a dominant role in producing quiescent galaxies for more massive galaxies, while less massive galaxies are quenched mostly through the environmental effect, with the transition mass around 1-2e10 Msun in the group/cluster environment.

1312.4747
Discovery of a large number of candidate proto-clusters traced by ~15 Mpc-scale galaxy over densities in COSMOS
Chiang, Overzier, Gebhardt

Find 36 candidate progo-cluster structures at 1.6<z<3.1, from smoothed 3d galaxy density maps and a set of matched simulations incorporating the dominant observational effects (galaxy selection and photo-z uncertainties).  Confirm that the observed ~15 comoving Mpc scale clustering is consistent with LCDM.  These candidates are possible progenitors of z~0 1e15 Msun clusters.  About 15-40% of photometric galaxy candidates are expected to be true proto-cluster members that will merge into a cluster-scale halo by z=0.  Provide targets for spec-z follow-ups and studies of cluster formation.  …

1312.4755
The nature and origin of magnetic fields in early-type stars
Braithwaite

Review current knowledge of B-fields in stars more massive than around 1.5 Msun, in particular their nature and origin.  This includes the strong B-fields found in a subset of the population and the fossil field theory invoked to explain them; the sub gauss fields detected in Vega and Sirius and their possible origin; and what can be inferred about magnetic activity in massive stars and how it might be linked to subsurface convection.

1312.4841
The clustering of galaxies in the SDSS-III Baryon Oscillation spectroscopic survey: including covariance matrix errors
Percival, Ross, … et al

Improved methodology for including covariance matrices in the error budget of BOSS, revisiting DR9 analyses, and describing a method that is used in DR10/11 analyses presented in companion papers.  The precise analysis method adopted is becoming increasingly important, due to the precision that BOSS can now reach: even using as many as 600 mock catalogues to estimate covariance of 2pt clustering measurements can still lead to an increase in the errors of ~20%, depending on how the cosmo parameters of interest are measured.  In this paper, extend previous work on this contribution to the error budget, deriving formulae for errors measured by integrating over the likelihood, and to the distribution of recovered best-fit parameters fitting the simulations also used to estimate the covariance matrix.  Both are situations that previous analyses of BOSS have considered.  Apply the formulae derived to BAO and RSD measurements from BOSS in the companion papers.  To further aid these analyses, consider the optimum number of bins to use for 2pt measurements using the monopole PS or correlation function for BAO, and the monopole and quadrupole moments of the correlation function for anisotropic-BAO and RSD measurements.

1312.4854
The clustering of galaxies in the SDSS-III baryon oscillation spectroscopy survey: cosmological implications of the full shape of the clustering wedges in the data release 10 and 11 galaxy samples
Sanchez, et al

Explore the cosmological implications of angle-averaged xi(s) and the clustering wedges, xi_perp(s) and xi_para(s), of the LOWZ and CMASS galaxy samples from DR10 and 11.  Results show no significant evidence for a deviation from the standard LCDM model.  The combination of the information from clustering measurements with recent data from the CMB is sufficient to constrain the curvature of the Universe to Omega_k=0.0010pm0.0029, the total neutrino mass to Sum m_nu<0.23 eV (95% CL) the effective number of relativistic species to N_eff=3.31pm0.27, ad the DE EoS to w_DE=-1.051 pm 0.076.  These limits are further improved by adding information from SNIa and BAO from other samples.  This data set combination is completely consistent with a time-independent DE EoS, in which case w_DE=-1.024pm0.052.  Explore the constraints on the growth-rate of cosmic structures assuming f(z)=Omega_m(z)^gamma and obtain gamma=0.69pm0.15, in agreement with the predictions from GR of gamma=0.55.

1312.4862
Black hole spin properties of 130 AGN
Daly, Sprinkle

SMBHs may be described by their mass and spin.  When active, it provides a probe of the state of the BH system; spin of a BH can be estimated when the BH mass and beam power of the source are known for sources with powerful outflows.  75 SMBH spins obtained, include radio galaxies and quasars, with 0<z<2.  Combine with previous values obtained for other galaxies and quasars, for a total of 130 spin values; all sources associated with massive elliptical galaxies.  New values obtained are similar to those obtained earlier at similar redshift, and range from about 0.1 to 1 for FRII radio sources.  The overall results are consistent with those obtained previously: the spins tend to decrease with decreasing redshift for the FRII sources studied.  There is a hint that the range of values of BH spin at a given redshift is larger for FRII quasars than for FRII radio galaxies.  There is no indication of a strong correlation between SMBH mass and spin for the SMBHs studied here.  The relation between beam power and BH mass is obtained and used as a diagnostic of the outflows and the dependence of the B-field strength on BH mass.

1312.4877
The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: baryon acoustic oscillations in the data release 10 and 11 galaxy samples
Anderson et al

DR11: 1e6 galaxies and 8500 sq. deg., 0.2<z<0.7.  Compare realists with those from DR9 and DR10 samples.  Assuming LCDM, DR11 sample covers 13 Gpc^3 and is the largest region of the Universe surveyed at this density.  Measure the correlation function and PS, including density-field reconstruction of the BAO feature.  The acoustic features are detected at a significance of over 7 sigma in both the correlation function and PS.  Fitting for the position of the acoustic features measures the distance relative to the sound horizon at the drag epoch, r_d, which has a value of r_d,fid=149.28 Mpc in this paper's fiducial cosmology.  Find D_V=1264pm24 Mpc (r_d/r_d,fid) at z=0.32 and D_V=2056pm20 Mpc (r_d/r_d,fid) at z=0.57.  At 1.0%, this patter measure is the most precise distance constraint ever obtained from a galaxy survey.  Separating the clustering along and transfers to the LoS yields measurements at z=0.57 of D_A=1421pm20(…) Mpc and H=96.8pm3.4 km/s/Mpc (…).  Measurements of the distance scale are in good agreement with previous BAO measurements and with the predictions from CMB data for a spatially flat CDM with a cosmological constant.

1312.4889
The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: single-probe measurements from CMASS and LOWZ anisotropic galaxy clustering
Chuang, et al

Provide accurate measurements on H^-1 R_fid^(-1.0), D_A R_fid^(-0.96), f sigma8(Omega_m h^2)^0.45, where R_fid == r_s/r_s,fid, r_s is the comoving sound horizon at the drag epoch, and f_s,fid is the sound scale of the fiducial cosmology used in this study.  Also extract cosmological constraints from BOSS DR11 LOWZ sample, at the effective z=0.32, by including small scales (down to 30 Mpc/h), and model small scales with FoG effect.  The parameters which are not well constrained by galaxy clustering analysis are marginalized over  with wide flat priors.  Since no priors from other data sets, e.g., CMB, are adopted and no DE models are assumed, results from BOSS CMASS and LOWZ galaxy clustering alone may be combined with other data sets, i.e., CMB, SNe, lensing or other galaxy clustering data to constraint the parameters of a given cosmo model.  Find the redshift distortion measurements from most of the galaxy clustering analyses (including this study) favor WMAP9 than Planck and favor wCDM than LCDM or oLCDM.  The uncertainty on the DE EoS parameter from CMB+CMASS is about 8 %.

1312.4899
The clustering of galaxies in the SDSS-III baryon oscillation spectroscopic survey: measuring growth rate and geometry with anisotropic clustering
Samushia, Reid, White, Percival, et al

Use the anisotropic clustering of galaxies in BOSS DR11 CMASS sample to measure the linear growth rate of structure, the Hubble expansion rate and the comoving distance scale.  Sample covers 8498 sq.deg and encloses an effective volume of 6.0 Gpc^3 at an effective z of 0.57.  Find f sigma8 = 0.441 pm 0.044, H=93.1pm3.0 km/s/Mpc [what?] and D_A = 1380 pm 23 Mpc when fitting the growth and expansion rate simultaneously.  When the BG expansion is fixed to flat LCDM prediction by Planck, find f sigma8=0.447pm0.028 (6% accuracy).  While measurements are generally consistent with the predictions of LCDM and GR, they mildly favor models in which the strength of gravitational interactions is weaker than what is predicted by GR.  Combining measurements with recent CMB data results in tight constraints on basic cosmological parameters and deviations from the standard cosmological model.  Separately varying these parameters, find w=--0.983 pm 0.075 (8% accuracy) and gamma = 0.69 pm 0.11 (16% accuracy) for the effective equation of state of DE and the growth rate index, respectively.  Both constraints are in good agreement with the standard model values of w=-1 and gamma=0.554.

1312.4938
What astroseismology can do for exoplanets: Kepler-410A b is a small Neptune around aright star, in an eccentric orbit consistent with low obliquity
Van Eylen et al

Employing astroseismology, using constraints from the transit light curve, adaptive optics and speckle images, and Spitzer transit observations, demonstrate that the candidate can only be an exoplanet orbiting Kepler-410A, with a fainter star Kepler-410B.  In addition, rotational splitting of the pulsation modes allows for a measurement of Kepler 410A's inclination and rotation rate, indicating low obliquity.  Transit timing variations indicate the presence of at least one additional (non-transiting) planet in the system.

1312.4944
Radiation magnetohydrodynamic simulations of protostellar collapse: low-metallicity environments
Tomida

Radiation transfer is one of the key processes among many physical processes involved in SF, since it dominantly controls the thermodynamics.  Because metallicities control opacities, they are one of the important environmental parameters which affect SF processes.  Investigate protostellar collapse in solar-metallicity and low-metallicity (Z=0.1 Zsun) environments using 3d radiation hydrodynamic and magnetohydrodynamic simulations.  Because radiation cooling is more effective in the low-metallicity environments, first cores are colder and have lower entropies.  As a result, first cores are smaller, less massive and have shorter lifetimes in the low-metallicity clouds.  Therefore, first cores would be less likely to be found in low-metallicity SF clouds.  This also implies that first cores tend to be more gravitationally unstable and susceptible to fragmentation.  The evolution and structure of protostellar cores formed after the second collapse weakly depend on metallicities in the spherical and magnetized models despite the large difference in the metallicities.  Because this is due to the change of the heat capacity by dissociation and ionization of hydrogen, it is a general consequence of the second collapse as long as the effects of radiation cooling are not very large during the second collapse.  On the other hand, the effects of different metallicities are more significant in the rotating models without magnetic fields, because they evolve slower than other models and therefore more affected by radiation cooling.

19-3




1312.5310
Simulated star formation rate functions at $\bf{z\sim4-7}$, and the role of feedback in high-$\bf{z}$ galaxies
Tescari, … Borgani, et al

Study the role of feedback from SNe and BHs in the evolution of SFR function (SFRF) of z~4-7 galaxies.  Use a new set of cosmological hydrosims, ANGUS (AustraliaN Gadget-3 early Universe Simulations), run with a modified and improved version of the parallel TreePM-smoothed particle hydrodynamics code GADGET-3 called P-GADGET3(XXL), that includes a self-consistent implementation of stellar evolution and metal enrichment.  SN driven galactic winds and AGN act simultaneously in a complex interplay.  The SFRF is insensitive to feedback prescription at z>5, meaning that it cannot be used to discriminate between feedback models during reioiniation.  However, the SFRF is sensitive to the details of feedback prescription at lower z.  By exploring different SN driven wind velocities and regimes for the AGN feedback, find that the key factor for reproducing the observed SFRFs is a combination of "strong" SN winds and early AGN feedback in low mass galaxies.  Conversely, show that the choice of initial mass function and inclusion of metal cooling have less impact on the evolution of the SFRF.  When variable winds are considered, find that a non-aggressive wind scaling is needed to reproduce the SFRFs at z>=4.  Otherwise, the amount of objects with low SFRs is greatly suppressed and at the same time winds are not effective enough in the most massive systems.  

1312.5324
Constraining the variation in fine-structure constant using SDSS DR8 QSO spectra
Rahmani, Maheshwari, Srianand

Find Delta alpha/alpha = -2.1pm1.6e-5 based on a well selected sample of 2347 QSOs from SDSS DR8 with 0.02<z<0.74, using O III nebular emission lines from QSOs.  A factor of ~4 improvement due to larger sample is expected based on a 14x bigger sample used here, suggesting errors are mainly dominated by statistical uncertainty.  Also find the ration of transition probabilities corresponding to the O III 5007 A and 4959 A lines to be 2.933pm0.002, in good agreement with the NIST measurements.

1312.5326
The origin and universality of the stellar initial mass function
Offner, … Hopkins, et al

Review current theories for the origin of the stellar IMF with particular focus on the extent to which the IMF can be considered universe across various environments.  Place the issue in an observational context: summarize the techniques used to determine the IMF for different stellar populations, the uncertainties affecting the results, and the evidence for systematic departures from universality under extreme circumstances.  Next, consider theories for the formation of pre-stellar cores by turbulent fragmentation and the possible impact of various thermal, hydrodynamic and magneto-hydrodynamic instabilities.  Address the conversion of pre-stellar cores into stars and evaluate the roles played by different processes: competitive accretion, dynamical fragmentation, ejection and starvation, filament fragmentation and filamentary accretion flows, disk formation and fragmentation, critical scales imposed by thermodynamics, and magnetic breaking.  Present explanations for the characteristic shapes of the present-day pre-stellar core mass function and the IMF and consider what significance can be attached to their apparent similarity.  Substantial computational advances have occurred in recent years; review the numerical simulations that have been performed to predict the IMF directly and discuss the influence of dynamics, time-dependent phenomena, and initial conditions.

1312.5334
The astrophysics source code library: where do we go from here?
Allen et al

Started in 1999, grown from repository of 40 codes to 700 in the past 3 years, now indexed by ADS.  Examine the future of ASCL, the challenges, the rational, and the need to balance what might be done with what resources are available to accomplish [?].

1312.5341
The thermal Sunyaev Zel'dovich effect power spectrum in light of Planck
McCarthy, et al

The amplitude of the tSZ power spectrum is extremely sensitive to the abundance of galaxy clusters and therefore to fundamental cosmological parameters that control their growth, such as sigma8 and Omega_m.  Explore the sensitivity of the tSZ PS to important non-graviational ('sub-grid') physics by employing the cosmo-OWLS suite of large-volume cosmological hydrosims, run in both the Planck and WMAP7 best-fit cosmologies.  On intermediate and small scales (ell>~1000), accessible with SPT and ACT, the predicted tSZ PS is highly model dependent, with AGN feedback having a particularly large effect.  However, at large scales, observable with the Planck telescope, the effects of sub-grid physics are minor.  Comparing the simulations with observations, find a significant amplitude offset on all measured angular scales (including large scales), if the Planck best-fit cosmology is assumed by the simulations.  This is shown to be a generic result for all current tSZ models.  By contrast, if the WMAP7 cosmology is adopted, there is full consistency [has the "current tSZ models" been affected by WMAP7 cosmology in the first place?!] with the Planck PS measurements on large scales and agreement at the 2 sigma level with the SPT/ACT measurements at intermediate scales for this fiducial AGN model, which LeBrun+ (2014) have shown reproduces the 'resolved' properties of the local cluster population remarkably well.  These findings strongly suggest that there are significantly fewer massive galaxy clusters than expected for the Planck best-fit cosmology, which is consistent with recent measurements of the tSZ number counts.  The findings here therefore pose a significant challenge to the cosmological parameter values preferred by the Planck primary CMB analyses.

1312.5360
Pair-instability supernovae in the local universe
Whalen, et al

The discovery of 150-300 Msun stars in the Local Group and pair-instability supernova (PI SN) candidates at low z has excited interest in this exotic explosion mechanism and poses serious challenges to current theories of galactic SF.  Realistic light curves for PI SNe at near-solar metallicities are key to identifying and properly interpreting these events as more are found.  Model the evolution and explosions of Z~0.1-0.4 Z_sun PI SN progenitors.  These stars must be 150-500 Msun at birth because they lose up to 80% of their mass to strong line-driven winds and explode as bare He cores.  Their light curves and spectra are quite different from those of Pop III pair-instability explosions, which therefore cannot be used as templates for low-z events.  Numerical models show that non-zero metallicity PI SNe are generally dimmer than Pop III explosions but can still be detected at z~0.1-1 by the new SN factories.  They also reveal that pair-instability explosions can masquerade as dim, short-duration SNe, and that under the right conditions they could be hidden in a wide variety of SN classes.  Also report for the first time that some PI SNe can create BHs with masses of ~100 Msun.

1312.5365
The star formation rate of molecular clouds
Padoan et al

Molecular clouds are shaped into a complex filamentary structure by supersonic turbulence, with only a small fraction of the cloud mass channeled into collapsing protostars over a free-fall time of the system.  In recent years, the physics of supersonic turbulence has been widely explored with computer simulations, leading to statistical models of this fragmentation process, and to the prediction of the SFR as a function of fundamental physical parameters of molecular clouds, such as the virial parameter,r the rms Mach number, the compressive fraction of the turbulence driver, and the ratio of gas to magnetic pressure.  Infrared space telescopes, as well as ground-based observatories have provided unprecedented probes of the filamentary structure of molecular clouds and the location of forming stars within them.