Day 610

Tuesday.

1403.3689
3D-HST WFC3-selected photometric catalogs in the five CANDELS/3D-HST fields: photometry, photometric redshifts and stellar masses
Skelton, … van Dokkum, Franx, Kriek, Oesch, et al

The 3D-HST and CANDELS programs have obtained WFC3 and ACS spectroscopy and imaging over 5 fields, comprising a total area of ~900 sq. arcmin: EGIS, COSMOS, GOODS-North, GOODS-South, and the UKIDSS UDS field.  All these fields have a wealth of publicly available imaging datasets in addition to the HST data, which makes it possible to construct the SEDs of objects over a wide wavelength range.  In this paper, describe a photometric analysis of the CANDLES and 3D-HST HST imaging and the ancillary imaging data at wavelengths 0.3um-8um.  Objects were selected in the WFC3 NIR bands, and their SEDs were determined by carefully taking the effects of the PSF into account.  A total of 147 distinct imaging datasets were used in the analysis.  The photometry is made available in the form of 6 catalogs: one for each field, as well as a master catalog containing all objects in the entire survey.  Also provide derived data products: photo-z, determined with the EAZY code, and stellar population parameters determined with the FAST code.  Make all the imaging data that were used in the analysis available, including reductions of the WFC3 imaging in all five fields.  3D-HST is a spectroscopic survey with the WFC3 and ACS prisms, and the photometric catalogs presented here constitute a necessary first step in the analysis of these grism data.  In a companion paper (Momcheva+ in prep), present line diagnostics and improved redshifts from an analysis of the combination of the photometry with the grism spectra.  All the data presented in this paper are available through the 3D-HST website.

1403.3691
Discovery of a rich proto-cluster at z=2.9 and associated diffuse cold gas in the VIMOS Ultra-Deep Survey (VUDS)
Cucciati, Le Fevre, Capak, et al

A massive proto-cluster at z=2.895; one of the rare structures at z~3 not identified around AGNs or radio galaxies; an ideal laboratory to study galaxy formation in dense environments.  The structure comprises of 12 galaxies with secure spec-z in an area of 7'x8' within Delta z = 0.016.  The measured galaxy number overdensity is delta_g = 12pm2.  This overdensity has total mass of m~8.1e14 Msun in a volume of (15 Mpc)^3.  Simulations indicate that such an overdensity at z~2.9 is a proto-cluster that will collapse in a cluster of total mass M~2.5e15 Msun at z=0.  Compare the properties of the galaxies within the overdensity with a control sample at the same z but outside the overdensity.  Did not find any statistically significant difference between the properties (stellar mass, SFR, sSFR, NUV-r, r-K) of the galaxies inside and outside the overdensity.  The stacked spectrum of galaxies in the background of the overdensity shows a significant absorption feature at the wavelength of Lya redshifted at z=2.895 with a rest frame EW=4pm1.4A.  Stacking only BG galaxies without intervening sources at z~2.9 along their LoS, find that this absorption feature has a rest from EW of 10.8pm3.7A, with a detection S/N of ~4.  Verify that this measurement is not likely to be due to noise fluctuations.  These EW values imply a high column density (N(HI)~3-20e19cm^-2), consistent with a scenario where such absorption is due to intervening cold streams of gas, that are falling into the halo potential wells of the proto-cluster galaxies.

1403.3692
Discovering extremely compact and metal-poor, star-forming dwarf galaxies out to z~0.9 in the VIMOS Ultra-Deep survey
Amorin, Le Fèvre, Capak, et al

Discovery of 31 low-luminosity (-14.5<M_AB(B)<-18.8) extreme emission line galaxies (EELGs) at 0.3<z<0.9 identified by their unusually high rest-frame EWs (100<EW[OIII]<1700A) as part of the VIMOS VUDS.  VIMOS poetical spectra of I_AB~25 mag along with multi wavelength photometry and HST imaging are used to investigate spectrophotometric properties of this sample and explore the very low stellar mass end (M*<1e8 Msun) of the luminosity-metallicity (LZR) and mass-metallicty (MZR) relations at z<1.  Characterized by their extreme compactness (R50 < 1 kpc), low stellar mass and enhanced sSFRs (SFR/M*~1e-9-1e-7 /yr), the VUDS EELGs are blue dwarf galaxies likely experiencing the first stages of a vigorous galaxy-wide starburst.  Using T_e sensitive direct and strong-line methods, find that VUDS EELGs are low-metallicity (7.5<12+log(O/H)<8.3) galaxies with high ionization conditions i.e., median OIII/OII=4(pm5).  Moreover, find at least 3 objects showing HeII 4686A emission and four EELGs of extremely low metallicities (<10% solar).  The LAR and MZR followed by EELGs are broadly consistent with the extrapolation toward low mass of these relations from previous studies at similar redshift.  However, find evidences that galaxies with younger and more vigorous SF -- as characterized by their larger Hbeta and [OIII] EWs, sSFR and higher ionization parameters -- tend to be more metal-poor at a given luminosity and stellar mass.  These results are discussed in the context of the fundamental metallicity relation linking mass metallicity and SFR.

1403.3693
The VIMOS Ultra-Deep Survey (VUDS): fast increase of the fraction of strong Lyman alpha emitters from z=2 to z=6
Cassata, et al

The aim is to constrain the evolution of the fraction of Lya emitters among UV selected SF galaxies at 2<z<6, and to measure the stellar escape fraction of Lya photons over the same z range.  Use 4000 spectroscopically confirmed SF galaxies at 2<z<6; sample consists of UV luminosities brighter than M* at 2<z<6, and luminosities down one magnitude fainter than M* at 2<z<3.5.  Find that 80% of the SF galaxies have EW0(Lya)<10A, and correspondingly f_esc(Lya)<1%.  By comparing these results with literature, conclude that the bulk of the Lya luminosity at 2<z<6 comes from galaxies that are fainter in the UV than those sampled in this work.  The strong Lya emitters constitute, at each redshfit, the tail of the distribution of the galaxies with extreme EW0(Lya) and f_exc(Lya).  This tail of large EW0 and f_esc(Lya) becomes more important as the z increases, and causes the fraction of Lya with E0>25A to increase from 5% at z=2 to 30% at z=6, with the increase being relatively stronger beyond z=4.  Observe no difference for the narrow range of UV luminosities explored in this work, between the fraction of strong Lya emitters among galaxies fainter or brighter than M*, although the fraction for the FUV faint galaxies evolves faster, at 2<z<3.5, than for the bright ones.  Observe an anti correlation between E(B-V) and f_esc(Lya): generally galaxies with high f_esc(Lya) have also small amounts of dust (and vice versa).  However, when the dust content is low (E(B-V)<0.05) observe a very broad range of f_esc(Lya), ranging from 1e-3 to 1.  This implies that the dust alone is not the only regulator of the amount of escaping Lya photons.

1403.3697
Silk damping at a redshift of a billion: a new limit on small-scale adiabatic perturbations
Jeong, Pradler, Chluba, Kamionkowski

Study the dissipation of small-scale adiabatic perturbations at early times when the Universe is hotter than T~0.5 keV.  When the wavelength falls below the damping scale 1/kD, the acoustic modes diffuse and thermalize, causing entropy production.  Before neutrino decoupling, kD is primarily set by the neutrino shear viscosity; study the effect of acoustic damping on the relic neutrino number, primordial nucleosynthesis, DM freeze-out and baryogensis.  This sets a new limit on the amplitude of primordial fluctuations of DeltaR^2<0.007 at 1e4 Mpc^-1<k<1e5Mpc^-1 and a model dependent limit of DeltaR^2 < 0.3 at k<1e(20-25) Mpc^-1.

1403.3727
Cosmological spectral deconvolution
de Putter, Holder, Chang, Dore

Exploit the specific intensity of extragalactic light as a function of wavelength and direction on the sky, to measure spatial variations in the total extragalactic light emission and use these as a tracer of the cluttering of matter.  A main challenge is that the observed intensity as a function of wavelength is a convolution of the source luminosity density with the rest-frame SED.  In this paper, introduce the method of spectral deconvolution as a way to invert this convolution and extract the clustering information.  Show how one can use observations of the mean and angular fluctuations of extragalactic light as a function of wavelength, assuming statistical isotropy, to reconstruct jointly the rest-frame SED of the sources and the source spatial density fluctuations.  This method is more general than the all known line mapping technique as it does not rely on spectral lines in the emitted spectra.  After introducing the general formalism, discuss its implementation and limitations.  This formal paper sets the stage for future more practical studies.



1403.3804
Cosmic backgrounds due to the formation of the first generation of supermassive black holes
Biermann et al

The statistics of BHs and their masses strongly suggests that their mass distribution has a cutoff towards lower masses near 3e6 Msun.  This is consistent with a classical formation mechanism from the agglomeration of the first massive stars in the universe.  However, when the masses of the stars approach 1e6 Msun, the stars become unstable and collapse, possibly forming the first generation of cosmological BHs.  Speculate that the claimed detection of an isotropic radio background may constitute evidence of the formation of these first SMBHs, since their data are compatible in spectrum and intensity with synchrotron emission from the remnants.  The model proposed fulfills all observational conditions for the background, in terms of single-source strength, number of sources, FIR and gamma-ray emission.  The observed high energy neutrino flux is consistent with our calculations in flux and spectrum.  The proposal described in this paper may also explain the early formulation and growth of massive bulge-less disk galaxies as derived from the massive, gaseous shell formed during the explosion prior to the formation of a SMBH.

1403.3911
CMB lensing reconstruction using cut sky polarization maps and pure-$B$ modes
Pearson, Sherwin, Lewis

Simulate CMB polarization lensing reconstruction for the EE and EB quadratic estimators with current-generation noise levels and resolution, and show that without boundary effects the known and expected zeroth and first order N(0) and N(1) biases provide an adequate model for non-signal contributions to the lensing power spectrum estimators.  Small sky areas present a number of additional challenges for polarization lensing reconstruction, including leakage of E modes into B modes.  Show how simple windowed estimators using filtered pure-B modes can greatly reduce the mask-induced mean-field lensing signal and reduce variance in the estimators.  This provides a simple method (used with recent observations) that gives an alternative to more optimal but expensive inverse-variance filtering.

1403.3938
THe VIMOS Ultra-Deep Survey: ~10,000 galaxies with spectroscopic redshifts to study galaxy assembly at early epochs 2<z<~6
Le Fevre et al

Present VUDS, a spectroscopic z survey of ~10,000 very faint galaxies to study the major phase of galaxy assembly 2<z<~6.  The survey covers 1 deg^2 in 3 separate fields: COSMOS, ECDFS and VVDS-02h, with target selection based on an inclusive combination of photometric z and color properties.  Spectra covering 3650<lambda<9350A are obtained with VIMOS on the ESO-VLT with integration times of 14h.  Present the survey strategy, the target selection, the data processing, ad well as the z measurement process, emphasizing the specific methods adapted to this high z range.  The spectra quality and z reliability are discussed, and derive a completeness in z measurement of 91%, or 74% for the most reliable measurements, down to i_AB=25, and measurements are performed all the way down to i_AB=27.  The redshift distribution of the main sample peaks at z=3-4 and extends over a large z range mainly in 2<z<6.  At 3<z<5, the galaxies cover a large range of luminosities -23<M_U<-20.5, stellar mass 1e9 Msun<M*<1e11 Msun, and SFRs comparison between spectroscopic and photometric redshifts as well as color selection demonstrate the effectiveness of the selection scheme.  With ~6000 galaxies with reliable spectroscopic z in 2<z<6 expected when complete, this survey is the largest at these redshifts and offers the opportunity for unprecedented studies of the SF galaxy population and its distribution in large scale structures during the major phase of galaxy assembly.

1403.3985
BICEP2 I: detection of B-mode polarization at degree angular scales
BICEP2 Collaboration

Report results from CMB polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode PS around ell=80.  The telescope comprised a 26 cm aperture all-cold refracting optical system equipped with a focal plane of 512 antenna coupled transition edge sensor (TES) 150 GHz bolometers each with temperature sensitivity of apprix 300 uk.sqrt(s).  BISEP2 observed from the PS for 3 seasons from 2010 to 2012.  A low-foreground region of sky with an effective area of 380 sq. deg was observed to a depth of 87 nK-degrees in Stokes Q and U.  In this paper, describe the observations, data reduction, maps, simulations and results.  Find an excess of B-mode power over the base lensed -LCDM expectation in the range 30<ell<150, inconsistent with the null hypothesis at a significance of >5sigma.  Through jackknife tests and simulations based on detailed calibration measurements, show that systematic contamination is much smaller than the observed excess.  Also estimate potential FG signals and find that available models predict these to be considerably smaller than the observed signal.  These FG models possess no significant cross-correlation with the maps.  Additionally, cross-correlating BISEP2 against 100 GHz maps from the BICEP1 experiment, the excess signal is confirmed with 3 sigma significance and its spectral index is found to be consistent with that of the CMB, disfavoring synchrotron or dust at 2.3 sigma and 2.2 sigma, respectively.  The observed B-mode PS is well-fit by a lensed-LCDM+tensor theoretical model with tensor/scalar ratio r=0.20pm0.05, with r=0 disfavored at 7.0 sigma.  Subtracting the best available estimate for FG dust modifiers the likelihood slightly so that r=0 is disfavored at 5.9 sigma.

1403.4215
Galaxy shapes and intrinsic alignments in the MassiveBlack-II simulation
Tenneti, Mandelbaum, Matteo, Feng, Khandai

Investigate the shapes and relative orientations of the stars and DM of halos and sub halos (central and satellite) extracted form the MassiveBlack-II simulation, a state-of-the-art high resolution hydro cosmo sim which includes stellar and AGN feedback in a volume of (100Mpc/h)^3.  Consider redshift evolution from z=1 to 0.06 and mass evolution within the range of sub halo masses, 1e10-6e14Msun/h.  The shapes of the DM distributions are generally more round than the shapes defined by stellar matter.  The projected RMS ellipticity per component for stellar matter is measured to be e_rms=0.28 at z=0.3 for M_subhalo>1e12 Msun/h, which compares favorably with observational measurements.  Find that the shapes of stellar and DM are more round for less massive subhaloes and at lower zs.  By directly measuring the relative orientation of the stellar matter and DM of subgroups, find that, on average, the misalignment between the two components is larger for less massive subhaloes.  The mean misalignment angle varies from ~30-10deg for M~1e10-14 Msun/h and shows a weak dependence on z.  Also compare the misalignment angles in central and satellite subhaloes at fixed subhalo mass, and find that centrals are more misaligned than satellites.  Present fitting formulae for the shapes of dark and stellar matter in sub haloes and also the probability distributions of misalignment angles.

1403.4230
VIMOS Ultra-deep survey (VUDS): witnessing the assembly of a massive cluster at $z\sim3.3$
Lemaux et al

Systematic search for over dense environments in z>2 early universe, and report on a massive proto-cluster at z=3.29.  This pro to-cluster is characterized by both the large overdensity of spectroscopically confirmed members, and a significant overdensity in photo-z members.  The halo mass of this proto-cluster is estimated, by a variety of methods, to be roughly 3e14 Msun at z~3.3, which, evolved to z=0 results in a halo mass rivaling or exceeding that of the Coma cluster.  The properties of 19 spectroscopically confirmed member galaxies are compared with a large sample of VUDS/VVDS galaxies in lower density field environments at similar redshifts.  Find tentative evidence for an excess of redder, brighter, and more massive galaxies within the confines of the proto-cluster relative to the field populations, which suggests that the beginning of environmentally-induced quenching is being observed.  The properties of these galaxies are investigated, including a discussion of the brightest proto-cluster galaxy which appears to be undergoing vigorous coeval nuclear and starburst activity.  The remaining member galaxies appear to have characteristics which are largely similar to the field population.  Though find weaker evidence of the suppression of the median SFRs amongst and differences in stacked spectra of member galaxies with respect to the field, defer any conclusions of these trends to future work with the ensemble of proto-structures that are found in the full VUDS sample.