Browsing by Subject "cosmology: observations"

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Ancient Light From Young Cosmic Cities: Physical And Observational Signatures Of Galaxy Proto-Clusters
(2013-12) Chiang, Yi-Kuan; Overzier, Roderik; Gebhardt, Karl; Chiang, Yi-Kuan; Overzier, Roderik; Gebhardt, Karl
A growing number of galaxy clusters at z = 1-2 is being discovered as part of deep optical, IR, X-ray, and Sunyaev-Zel'dovich effect surveys. For a complete picture of cluster formation, however, it is important that we also start probing the much earlier epoch, between redshifts of about 2 and 7, during which these clusters and their galaxies first began to form. Because the study of these so-called proto-clusters is currently quite limited by small number statistics, widely varying selection techniques, and many assumptions, we have performed a large systematic study of cluster formation utilizing cosmological simulations. We use the Millennium Simulations to track the evolution of dark matter and galaxies in about 3000 clusters from the earliest times to z = 0. We define an effective radius R-e for proto-clusters and characterize their growth in size and mass with cosmic time. We show that the progenitor regions of galaxy clusters (ranging in mass from similar to 10(14) to a few times 10(15) M-circle dot) can already be identified in galaxy surveys at very early times (at least up to z similar to 5), provided that the galaxy overdensities are measured on a sufficiently large scale (R-e similar to 5-10 Mpc comoving) and with sufficient statistics. We present the overdensities in matter, dark matter halos, and galaxies as functions of present-day cluster mass, redshift, bias, and window size that can be used to interpret the wide range of structures found in real surveys. We also derive the probability that a structure having a galaxy overdensity delta(gal), defined by a set of observational selection criteria, is indeed a proto-cluster, and we show how their z = 0 masses can already be estimated long before virialization. We present overdensity profiles as a function of radius, and we further show how the projected surface overdensities of proto-clusters decrease as the uncertainties in redshift measurements increase. We provide a table of proto-cluster candidates selected from the literature and discuss their properties in light of our simulation predictions. This paper provides the general framework that will allow us to extend the study of cluster formation out to much higher redshifts using the large number of proto-clusters that are expected to be discovered in, e. g., the upcoming HETDEX and Hyper Suprime-Cam surveys.
Bayesian Analysis Of An Anisotropic Universe Model: Systematics And Polarization
(2010-10) Groeneboom, Nicolaas E.; Ackerman, Lotty; Wehus, Ingunn K.; Eriksen, Hans Kristian; Ackerman, Lotty
We revisit the anisotropic universe model previously developed by Ackerman, Carroll, and Wise (ACW), and generalize both the theoretical and computational framework to include polarization and various forms of systematic effects. We apply our new tools to simulated Wilkinson Microwave Anisotropy Probe (WMAP) data in order to understand the potential impact of asymmetric beams, noise misestimation, and potential zodiacal light emission. We find that neither has any significant impact on the results. We next show that the previously reported ACW signal is also present in the one-year WMAP temperature sky map presented by Liu & Li, where data cuts are more aggressive. Finally, we re-analyze the five-year WMAP data taking into account a previously neglected (-i)(l-l')-term in the signal covariance matrix. We still find a strong detection of a preferred direction in the temperature map. Including multipoles up to l = 400, the anisotropy amplitude for the W band is found to be g = 0.29 +/- 0.031, nonzero at 9 sigma. However, the corresponding preferred direction is also shifted very close to the ecliptic poles at (l, b) = (96, 30), in agreement with the analysis of Hanson & Lewis, indicating that the signal is aligned along the plane of the solar system. This strongly suggests that the signal is not of cosmological origin, but most likely is a product of an unknown systematic effect. Determining the nature of the systematic effect is of vital importance, as it might affect other cosmological conclusions from the WMAP experiment. Finally, we provide a forecast for the Planck experiment including polarization.
A Catalog Of Near-Infrared Spectra From Type Ia Supernovae
(2009-09) Marion, G. H.; Hoflich, P.; Gerardy, C. L.; Vacca, W. D.; Wheeler, J. C.; Robinson, E. L.; Marion, G. H.; Robinson, E. L.
We present 41 near-infrared (NIR, 0.7-2.5 mu m) spectra from normal Type Ia supernovae (SNe Ia) obtained at epochs ranging from 14 days before to 75 days with respect to the maximum light date in the V band. All data were obtained at the Infrared Telescope Facility using the SpeX instrument. We identify many spectral features, measure the Doppler velocities, and discuss the chemical distribution of explosion products in SNe Ia. We describe procedures for smoothing data, fitting continua, and measuring absorption features to ensure consistency for measurement and analysis. This sample provides the first opportunity to examine and compare a large number of SNe Ia in this wavelength region. NIR data are a rich source of information about explosion products whose signatures are blended or obscured in other spectral regions and NIR observations probe a greater radial depth than optical wavelengths. We analyze similarities and differences in the spectra and we show that the progressive development of spectral features for normal SNe Ia in the NIR is consistent with time. We confirm the presence of O I, Mg II, Ca II, Si II, Fe II, and Co II in these SNe. Possible identifications are made for S I, Si III, Mn II, and Fe III. There is no evidence in these data for H I, He I, C I, or C II. As the explosion products expand and cool, progressively deeper layers are revealed. Thus, a time sequence of spectra examines the chemical structure and provides direct evidence of the physical properties of SNe Ia from the outer layers to deep inside the SN. Measured Doppler velocities indicate that burning products in SNe Ia are distributed in distinct layers with no large-scale mixing. Carbon is not detected in these data, in agreement with previous results with NIR data establishing very low limits on carbon abundance in SNe Ia. Carbon burning products, O and Mg, are plentiful in the outer layers suggesting that the entire progenitor is burned in the explosion. The data provide a resource for investigations of cross-correlations with other data libraries that may further constrain SN Ia physics and improve the effectiveness of SNe Ia as cosmological distance indicators.
CfAIR2: Near-Infrared Light Curves of 94 Type Ia Supernovae
(2015-09) Friedman, Andrew S.; Wood-Vasey, W. M.; Marion, G. H.; Challis, Peter; Mandel, Kaisey S.; Bloom, Joshua S.; Modjaz, Maryam; Narayan, Gautham; Hicken, Malcom; Foley, Ryan J.; Klein, Christopher R.; Starr, Dan L.; Morgan, Adam; Rest, Armin; Blake, Cullen H.; Miller, Adam A.; Falco, Emilio E.; Wyatt, William F.; Mink, Jessica; Skrutskie, Mmichael F.; Kirshner, Rrobert P.; Marion, G. H.
CfAIR2 is a large, homogeneously reduced set of near-infrared (NIR) light curves (LCs) for Type Ia supernovae (SNe Ia) obtained with the 1.3 m Peters Automated InfraRed Imaging TELescope. This data set includes 4637 measurements of 94 SNe Ia and 4 additional SNe Iax observed from 2005 to 2011 at the Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona. CfAIR2 includes JHKs photometric measurements for 88 normal and 6 spectroscopically peculiar SN Ia in the nearby universe, with a median redshift of z similar to 0.021 for the normal SN Ia. CfAIR2 data span the range from -13 days to +127 days from B-band maximum. More than half of the LCs begin before the time of maximum, and the coverage typically contains similar to 13-18 epochs of observation, depending on the filter. We present extensive tests that verify the fidelity of the CfAIR2 data pipeline, including comparison to the excellent data of the Carnegie Supernova Project. CfAIR2 contributes to a firm local anchor for SN cosmology studies in the NIR. Because SN Ia are more nearly standard candles in the NIR and are less vulnerable to the vexing problems of extinction by dust, CfAIR2 will help the SN cosmology community develop more precise and accurate extragalactic distance probes to improve our knowledge of cosmological parameters, including dark energy and its potential time variation.
Discovery of a Large Number of Candidate Protoclusters Traced By Similar to 15 Mpc-Scale Galaxy Overdensities in COSMOS
(2014-02) Chiang, Yi-Kuan; Overzier, Roderick; Gebhardt, Karl; Chiang, Yi-Kuan; Overzier, Roderick; Gebhardt, Karl
To demonstrate the feasibility of studying the epoch of massive galaxy cluster Formation in a more systematic manner using current and future galaxy surveys, we report the discovery of a large sample of protocluster candidates in the 1.62 deg(2) COSMOS/UltraVISTA field traced by optical/infrared selected galaxies using photometric redshifts. By comparing properly smoothed three-dimensional galaxy density maps of the observations and a set of matched simulations incorporating the dominant observational effects (galaxy selection and photometric redshift uncertainties), we first confirm that the observed similar to 15 comoving Mpc-scale galaxy clustering is consistent with Lambda CDM models. Using further the relation between high-z overdensity and the present day cluster mass calibrated in these matched simulations, we found 36 candidate structures at 1.6 < z < 3.1, showing overdensities consistent with the progenitors of M-z=0 similar to 10(15) M-circle dot clusters. Taking into account the significant upward scattering of lower mass structures, the probabilities for the candidates to have at least M-z=0 similar to 10(14) M-circle dot are similar to 70%. For each structure, about 15%-40% of photometric galaxy candidates are expected to be true protocluster members that will merge into a cluster-scale halo by z = 0. With solely photometric redshifts, we successfully rediscover two spectroscopically confirmed structures in this field, suggesting that our algorithm is robust. This work generates a large sample of uniformly selected protocluster candidates, providing rich targets for spectroscopic follow-up and subsequent studies of cluster Formation. Meanwhile, it demonstrates the potential for probing early cluster Formation with upcoming redshift surveys such as the Hobby-Eberly Telescope Dark Energy Experiment and the Subaru Prime Focus Spectrograph survey.
Evidence For A Correlation Between The Si II Lambda 4000 Width And Type Ia Supernova Color
(2011-06) Nordin, Jakob; Ostman, Linda; Goobar, Ariel; Balland, C.; Lampeitl, Hubert; Nichol, Robert C.; Sako, Masao; Schneider, Donald P.; Smith, Mathew; Sollerman, Jesper; Wheeler, J. Craig; Wheeler, J. Craig
We study the pseudo-equivalent width of the Si II lambda 4000 feature of Type Ia supernovae (SNe Ia) in the redshift range 0.0024 <= z <= 0.634. We find that this spectral indicator correlates with the light curve color excess (SALT2c) as well as previously defined spectroscopic subclasses (Branch types) and the evolution of the Si II lambda 6150 velocity, i.e., the so-called velocity gradient. Based on our study of 55 objects from different surveys, we find indications that the Si II lambda 4000 spectral indicator could provide important information to improve cosmological distance measurements with SNe Ia.
Evidence For Type Ia Supernova Diversity From Ultraviolet Observations With The Hubble Space Telescope
(2012-04) Wang, Xiaofeng; Wang, Lifan; Filippenko, Alexei V.; Baron, Eddie; Kromer, Markus; Jack, Dennis; Zhang, Tianmeng; Aldering, Greg; Antilogus, Pierre; Arnett, W. David; Baade, Dietrich; Barris, Brian J.; Benetti, Stefano; Bouchet, Patrice; Burrows, Adam S.; Canal, Ramon; Cappellaro, Enrico; Carlberg, Raymond G.; di Carlo, Elisa; Challis, Peter J.; Crotts, Arlin P. S.; Danziger, John I.; Della Valle, Massimo; Fink, Michael; Foley, Ryan J.; Fransson, Claes; Gal-Yam, Avishay; Garnavich, Peter M.; Gerardy, Chris L.; Goldhaber, Gerson; Hamuy, Mario; Hillebrandt, Wolfgang; Hoeflich, Peter; Holland, Stephen T.; Holz, Daniel E.; Hughes, John P.; Jeffery, David J.; Jha, Saurabh W.; Kasen, Dan; Khokhlov, Alexei M.; Kirshner, Robert P.; Knop, Robert A.; Kozma, Cecilia; Krisciunas, Kevin; Lee, Brian C.; Leibundgut, Bruno; Lentz, Eric J.; Leonard, Douglas C.; Lewin, Walter H. G.; Li, Weidong; Livio, Mario; Lundqvist, Peter; Maoz, Dan; Matheson, Thomas; Mazzali, Paolo A.; Meikle, Peter; Miknaitis, Gajus; Milne, Peter A.; Mochnacki, Stefan W.; Nomoto, Ken'ichi; Nugent, Peter E.; Oran, Elaine S.; Panagia, Nino; Perlmutter, Saul; Phillips, Mark M.; Pinto, Philip; Poznanski, Dovi; Pritchet, Christopher J.; Reinecke, Martin; Riess, Adam G.; Ruiz-Lapuente, Pilar; Scalzo, Richard A.; Schlegel, Eric M.; Schmidt, Brian P.; Siegrist, James; Soderberg, Alicia M.; Sollerman, Jesper; Sonneborn, George; Spadafora, Anthony; Spyromilio, Jason; Sramek, Richard A.; Starrfield, Sumner G.; Strolger, Louis G.; Suntzeff, Nicholas B.; Thomas, Rollin C.; Tonry, John L.; Tornambe, Amedeo; Truran, James W.; Turatto, Massimo; Turner, Michael; Van Dyk, Schuyler D.; Weiler, Kurt W.; Wheeler, J. Craig; Wood-Vasey, Michael; Woosley, Stanford E.; Yamaoka, Hitoshi; Wheeler, J. Craig
We present ultraviolet (UV) spectroscopy and photometry of four Type Ia supernovae (SNe 2004dt, 2004ef, 2005M, and 2005cf) obtained with the UV prism of the Advanced Camera for Surveys on the Hubble Space Telescope. This data set provides unique spectral time series down to 2000 angstrom. Significant diversity is seen in the near-maximum-light spectra (similar to 2000-3500 angstrom) for this small sample. The corresponding photometric data, together with archival data from Swift Ultraviolet/Optical Telescope observations, provide further evidence of increased dispersion in the UV emission with respect to the optical. The peak luminositiesmeasured in the uvw1/F250W filter are found to correlate with the B-band light-curve shape parameter Delta m(15)(B), but with much larger scatter relative to the correlation in the broadband B band (e.g., similar to 0.4 mag versus similar to 0.2 mag for those with 0.8 mag < Delta m(15)(B) < 1.7 mag). SN 2004dt is found as an outlier of this correlation (at > 3 sigma), being brighter than normal SNe Ia such as SN 2005cf by similar to 0.9 mag and similar to 2.0 mag in the uvw1/F250W and uvm2/F220W filters, respectively. We show that different progenitor metallicity or line-expansion velocities alone cannot explain such a large discrepancy. Viewing-angle effects, such as due to an asymmetric explosion, may have a significant influence on the flux emitted in the UV region. Detailed modeling is needed to disentangle and quantify the above effects.
The First Galaxies: Assembly Of Disks And Prospects For Direct Detection
(2011-04) Pawlik, Andreas H.; Milosavljevic, Milos; Bromm, Volker; Pawlik, Andreas H.; Milosavljevic, Milos; Bromm, Volker
The James Webb Space Telescope (JWST) will enable observations of galaxies at redshifts z greater than or similar to 10 and hence allow us to test our current understanding of structure formation at very early times. Previous work has shown that the very first galaxies inside halos with virial temperatures T-vir less than or similar to 10(4) K and masses M-vir less than or similar to 10(8) M circle dot at z greater than or similar to 10 are probably too faint, by at least one order of magnitude, to be detected even in deep exposures with JWST. The light collected with JWST may therefore be dominated by radiation from galaxies inside 10 times more massive halos. We use cosmological zoomed smoothed particle hydrodynamics simulations to investigate the assembly of such galaxies and assess their observability with JWST. We compare two simulations that are identical except for the inclusion of non-equilibrium H/D chemistry and radiative cooling by molecular hydrogen. In both simulations a large fraction of the halo gas settles in two nested, extended gas disks which surround a compact massive gas core. The presence of molecular hydrogen allows the disk gas to reach low temperatures and to develop marked spiral structure but does not qualitatively change its stability against fragmentation. We post-process the simulated galaxies by combining idealized models for star formation with stellar population synthesis models to estimate the luminosities in nebular recombination lines as well as in the ultraviolet continuum. We demonstrate that JWST will be able to constrain the nature of the stellar populations in galaxies such as simulated here based on the detection of the He1640 recombination line. Extrapolation of our results to halos with masses both lower and higher than those simulated shows that JWST may find up to a thousand star-bursting galaxies in future deep exposures of the z greater than or similar to 10 universe.
The First Galaxies: Assembly With Black Hole Feedback
(2012-07) Jeon, Myoungwon; Pawlik, Andreas H.; Greif, Thomas H.; Glover, Simon C. O.; Bromm, Volker; Milosavljevic, Milos; Klessen, Ralf S.; Jeon, Myoungwon; Pawlik, Andreas H.; Bromm, Volker; Milosavljevic, Milos
We study how the first galaxies were assembled under feedback from the accretion onto a central black hole (BH) that is left behind by the first generation of metal-free stars through self-consistent, cosmological simulations. X-ray radiation from the accretion of gas onto BH remnants of Population III (Pop III) stars, or from high-mass X-ray binaries (HMXBs), again involving Pop III stars, influences the mode of second generation star formation. We track the evolution of the BH accretion rate and the associated X-ray feedback starting with the death of the Pop III progenitor star inside a minihalo and following the subsequent evolution of the BH as the minihalo grows to become an atomically cooling galaxy. We find that X-ray photoionization heating from a stellar-mass BH is able to quench further star formation in the host halo at all times before the halo enters the atomic cooling phase. X-ray radiation from an HMXB, assuming a luminosity close to the Eddington value, exerts an even stronger, and more diverse, feedback on star formation. It photoheats the gas inside the host halo, but also promotes the formation of molecular hydrogen and cooling of gas in the intergalactic medium and in nearby minihalos, leading to a net increase in the number of stars formed at early times. Our simulations further show that the radiative feedback from the first BHs may strongly suppress early BH growth, thus constraining models for the formation of supermassive BHs.
The First Galaxies: Chemical Enrichment, Mixing, And Star Formation
(2010-06) Greif, Thomas H.; Glover, Simon C. O.; Bromm, Volker; Klessen, Ralf S.; Bromm, Volker
Using three-dimensional cosmological simulations, we study the assembly process of one of the first galaxies, with a total mass of similar to 10(8) M(circle dot), collapsing at z similar or equal to 10. Our main goal is to trace the transport of the heavy chemical elements produced and dispersed by a pair-instability supernova exploding in one of the minihalo progenitors. To this extent, we incorporate an efficient algorithm into our smoothed particle hydrodynamics code that approximately models turbulent mixing as a diffusion process. We study this mixing with and without the radiative feedback from Population III (Pop III) stars that subsequently form in neighboring minihalos. Our simulations allow us to constrain the initial conditions for second-generation star formation, within the first galaxy itself, and inside of minihalos that virialize after the supernova explosion. We find that most minihalos remain unscathed by ionizing radiation or the supernova remnant, while some are substantially photoheated and enriched to supercritical levels, likely resulting in the formation of low-mass Pop III or even Population II (Pop II) stars. At the center of the newly formed galaxy, similar to 10(5) M(circle dot) of cold, dense gas uniformly enriched to similar to 10(-3) Z(circle dot) is in a Stateof collapse, suggesting that a cluster of Pop II stars will form. The first galaxies, as may be detected by the James Webb Space Telescope, would therefore already contain stellar populations familiar from lower redshifts.
First-Year Sloan Digital Sky Survey-II (SDSS-II) Supernova Results: Constraints On Nonstandard Cosmological Models
(2009-10) Sollerman, Jesper; Mortsell, E.; Davis, T. M.; Blomqvist, M.; Bassett, Bruce; Becker, A. C.; Cinabro, David; Filippenko, Alexei V.; Foley, Ryan J.; Frieman, J.; Garnavich, Peter; Lampeitl, Hubert; Marriner, J.; Miquel, Ramon; Nichol, Robert C.; Richmond, M. W.; Sako, Masao; Schneider, Donald P.; Smith, Mathew; Vanderplas, J. T.; Wheeler, J. Craig; Wheeler, J. Craig
We use the new Type Ia supernovae discovered by the Sloan Digital Sky Survey-II supernova survey, together with additional supernova data sets as well as observations of the cosmic microwave background and baryon acoustic oscillations to constrain cosmological models. This complements the standard cosmology analysis presented by Kessler et al. in that we discuss and rank a number of the most popular nonstandard cosmology scenarios. When this combined data set is analyzed using the MLCS2k2 light-curve fitter, we find that more exotic models for cosmic acceleration provide a better fit to the data than the.CDM model. For example, the flat Dvali-Gabadadze-Porrati model is ranked higher by our information-criteria (IC) tests than the standard model with a flat universe and a cosmological constant. When the supernova data set is instead analyzed using the SALT-II light-curve fitter, the standard cosmological-constant model fares best. This investigation of how sensitive cosmological model selection is to assumptions about, and within, the light-curve fitters thereby highlights the need for an improved understanding of these unresolved systematic effects. Our investigation also includes inhomogeneous Lemaitre-Tolman-Bondi (LTB) models. While our LTB models can be made to fit the supernova data as well as any other model, the extra parameters they require are not supported by our IC analysis. Finally, we explore more model-independent ways to investigate the cosmic expansion based on this new data set.
Five-Year Wilkinson Microwave Anisotropy Probe (WMAP*) Observations: Bayesian Estimation Of Cosmic Microwave Background Polarization Maps
(2009-08) Dunkley, J.; Spergel, D. N.; Komatsu, Eiichiro; Hinshaw, G.; Larson, D.; Nolta, M. R.; Odegard, N.; Page, L.; Bennett, C. L.; Gold, B.; Hill, R. S.; Jarosik, N.; Weiland, J. L.; Halpern, M.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wollack, E.; Wright, Edward L.; Komatsu, Eiichiro
We describe a sampling method to estimate the polarized cosmic microwave background (CMB) signal from observed maps of the sky. We use a Metropolis-within-Gibbs algorithm to estimate the polarized CMB map, containing Q and U Stokes parameters at each pixel, and its covariance matrix. These can be used as inputs for cosmological analyses. The polarized sky signal is parameterized as the sum of three components: CMB, synchrotron emission, and thermal dust emission. The polarized Galactic components are modeled with spatially varying power-law spectral indices for the synchrotron, and a fixed power law for the dust, and their component maps are estimated as by-products. We apply the method to simulated low-resolution maps with pixels of side 7.2 deg, using diagonal and full noise realizations drawn from the WMAP noise matrices. The CMB maps are recovered with goodness of fit consistent with errors. Computing the likelihood of the E-mode power in the maps as a function of optical depth to reionization, tau, for fixed temperature anisotropy power, we recover tau = 0.091 +/- 0.019 for a simulation with input tau = 0.1, and mean tau = 0.098 averaged over 10 simulations. A "null" simulation with no polarized CMB signal has maximum likelihood consistent with tau = 0. The method is applied to the five-year WMAP data, using the K, Ka, Q, and V channels. We find tau = 0.090 +/- 0.019, compared to tau = 0.086 +/- 0.016 from the template-cleaned maps used in the primary WMAP analysis. The synchrotron spectral index, beta, averaged over high signal-to-noise pixels with standard deviation sigma(beta) < 0.25, but excluding similar to 6% of the sky masked in the Galactic plane, is - 3.03 +/- 0.04. This estimate does not vary significantly with Galactic latitude, although includes an informative prior.
Five-Year Wilkinson Microwave Anisotropy Probe Observations: Cosmological interpretation
(2009-02) Komatsu, Eiichiro; Dunkley, J.; Nolta, M. R.; Bennett, C. L.; Gold, B.; Hinshaw, G.; Jarosik, N.; Larson, D.; Limon, M.; Page, L.; Spergel, D. N.; Halpern, M.; Hill, R. S.; Kogut, A.; Meyer, S. S.; Tucker, G. S.; Weiland, J. L.; Wollack, E.; Wright, E. L.; Komatsu, Eiichiro
The Wilkinson Microwave Anisotropy Probe (WMAP) 5-year data provide stringent limits on deviations from the minimal, six-parameter. cold dark matter model. We report these limits and use them to constrain the physics of cosmic inflation via Gaussianity, adiabaticity, the power spectrum of primordial fluctuations, gravitational waves, and spatial curvature. We also constrain models of dark energy via its equation of state, parity-violating interaction, and neutrino properties, such as mass and the number of species. We detect no convincing deviations from the minimal model. The six parameters and the corresponding 68% uncertainties, derived from the WMAP data combined with the distance measurements from the Type Ia supernovae (SN) and the Baryon Acoustic Oscillations (BAO) in the distribution of galaxies, are: Omega(b)h(2) = 0.02267(-0.00059)(+0.00058), Omega(c)h(2) = 0.1131 +/- 0.0034, Omega(Lambda) = 0.726 +/- 0.015, n(s) = 0.960 +/- 0.013, tau = 0.084 +/- 0.016, and Delta(2)(R) = (2.445 +/- 0.096) x 10(-9) at k = 0.002 Mpc(-1). From these, we derive sigma(8) = 0.812 +/- 0.026, H-0 = 70.5 +/- 1.3 kms(-1) Mpc(-1), Omega(b) = 0.0456 +/- 0.0015, Omega(c) = 0.228 +/- 0.013, Omega(m)h(2) = 0.1358(-0.0036)(+0.0037), z(reion) = 10.9 +/- 1.4, and t(0) = 13.72 +/- 0.12 Gyr. With the WMAP data combined with BAO and SN, we find the limit on the tensor-to-scalar ratio of r < 0.22 (95% CL), and that n(s) > 1 is disfavored even when gravitational waves are included, which constrains the models of inflation that can produce significant gravitational waves, such as chaotic or power-law inflation models, or a blue spectrum, such as hybrid inflation models. We obtain tight, simultaneous limits on the (constant) equation of state of dark energy and the spatial curvature of the universe: -0.14 < 1 + w(0) < 0.12 (95% CL) and -0.0179 < Omega(k) < 0.0081 (95% CL). We provide a set of "WMAP distance priors," to test a variety of dark energy models with spatial curvature. We test a time-dependent w with a present value constrained as -0.33 < 1 + w(0) < 0.21 (95% CL). Temperature and dark matter fluctuations are found to obey the adiabatic relation to within 8.9% and 2.1% for the axion-type and curvaton-type dark matter, respectively. The power spectra of TB and EB correlations constrain a parity-violating interaction, which rotates the polarization angle and converts E to B. The polarization angle could not be rotated more than -5 degrees.9 < Delta alpha < 2 degrees.4 (95% CL) between the decoupling and the present epoch. We find the limit on the total mass of massive neutrinos of Sigma m(v) < 0.67 eV (95% CL), which is free from the uncertainty in the normalization of the large-scale structure data. The number of relativistic degrees of freedom (dof), expressed in units of the effective number of neutrino species, is constrained as N-eff = 4.4 +/- 1.5 (68%), consistent with the standard value of 3.04. Finally, quantitative limits on physically-motivated primordial non-Gaussianity parameters are -9 < f(NL)(local) < 111 (95% CL) and -151 < f(NL)(equil) < 253 (95% CL) for the local and equilateral models, respectively.
Five-Year Wilkinson Microwave Anisotropy Probe Observations: Data Processing, Sky Maps, and Basic Results
(2009-02) Hinshaw, G.; Weiland, J. L.; Hill, R. S.; Odegard, N.; Larson, D.; Bennett, C. L.; Dunkley, J.; Gold, B.; Greason, M. R.; Jarosik, N.; Komatsu, Eiichiro; Nolta, M. R.; Page, L.; Spergel, D. N.; Wollack, E.; Halpern, M.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wright, E. L.; Komatsu, Eiichiro
We present new full-sky temperature and polarization maps in five frequency bands from 23 to 94 GHz, based on data from the first five years of the Wilkinson Microwave Anisotropy Probe (WMAP) sky survey. The new maps are consistent with previous maps and are more sensitive. The five-year maps incorporate several improvements in data processing made possible by the additional years of data and by a more complete analysis of the instrument calibration and in-flight beam response. We present several new tests for systematic errors in the polarization data and conclude that W-band polarization data is not yet suitable for cosmological studies, but we suggest directions for further study. We do find that Ka-band data is suitable for use; in conjunction with the additional years of data, the addition of Ka band to the previously used Q- and V-band channels significantly reduces the uncertainty in the optical depth parameter, tau. Further scientific results from the five-year data analysis are presented in six companion papers and are summarized in Section 7 of this paper. With the five-year WMAP data, we detect no convincing deviations from the minimal six-parameter Lambda CDM model: a flat universe dominated by a cosmological constant, with adiabatic and nearly scale-invariant Gaussian fluctuations. Using WMAP data combined with measurements of Type Ia supernovae and Baryon Acoustic Oscillations in the galaxy distribution, we find (68% CL uncertainties): Omega(b)h(2) = 0.02267(-0.00059)(+0.00058), Omega(c)h(2) = 0.1131 +/- 0.0034, Omega(Lambda) = 0.726 +/- 0.015, n(s) = 0.960 +/- 0.013, tau = 0.084 +/- 0.016, and Delta(2)(R) = (2.445 +/- 0.096) x 10(-9) at k = 0.002 Mpc(-1). From these we derive sigma(8) = 0.812 +/- 0.026, H(0) = 70.5 +/- 1.3 km s(-1) Mpc(-1), Omega(b) = 0.0456 +/- 0.0015, Omega(c) = 0.228 +/- 0.013, Omega(m)h(2) = 0.1358(-0.0036)(+0.0037), z(reion) = 10.9 +/- 1.4, and t(0) = 13.72 +/- 0.12 Gyr. The new limit on the tensor-to-scalar ratio is r < 0.22 (95% CL), while the evidence for a running spectral index is insignificant, dn(s)/d ln k = - 0.028 +/- 0.020 (68% CL). We obtain tight, simultaneous limits on the (constant) dark energy equation of state and the spatial curvature of the universe: - 0.14 < 1 + w < 0.12 (95% CL) and -0.0179 < Omega(k) < 0.0081 (95% CL). The number of relativistic degrees of freedom, expressed in units of the effective number of neutrino species, is found to be N(eff) = 4.4 +/- 1.5 (68% CL), consistent with the standard value of 3.04. Models with N(eff) = 0 are disfavored at >99.5% confidence. Finally, new limits on physically motivated primordial non-Gaussianity parameters are -9 < f(NL)(local) < 111 (95% CL) and -151 < f(NL)(equil) < 253 (95% CL) for the local and equilateral models, respectively.
Five-Year Wilkinson Microwave Anisotropy Probe Observations: Galactic Foreground Emission
(2009-02) Gold, B.; Bennett, C. L.; Hill, R. S.; Hinshaw, G.; Odegard, N.; Page, L.; Spergel, D. N.; Weiland, J. L.; Dunkley, J.; Halpern, M.; Jarosik, N.; Kogut, A.; Komatsu, Eiichiro; Larson, D.; Meyer, S. S.; Nolta, M. R.; Wollack, E.; Wright, E. L.; Komatsu, Eiichiro
We present a new estimate of foreground emission in the Wilkinson Microwave Anisotropy Probe (WMAP) data, using a Markov chain Monte Carlo method. The new technique delivers maps of each foreground component for a variety of foreground models with estimates of the uncertainty of each foreground component, and it provides an overall goodness-of-fit estimate. The resulting foreground maps are in broad agreement with those from previous techniques used both within the collaboration and by other authors. We find that for WMAP data, a simple model with power-law synchrotron, free-free, and thermal dust components fits 90% of the sky with a reduced chi(2)(v) of 1.14. However, the model does not work well inside the Galactic plane. The addition of either synchrotron steepening or a modified spinning dust model improves the fit. This component may account for up to 14% of the total flux at the Ka band (33 GHz). We find no evidence for foreground contamination of the cosmic microwave background temperature map in the 85% of the sky used for cosmological analysis.
Five-Year Wilkinson Microwave Anisotropy Probe Observations: Likelihoods and Parameters from the WMAP Data
(2009-02) Dunkley, J.; Komatsu, Eiichiro; Nolta, M. R.; Spergel, D. N.; Larson, D.; Hinshaw, G.; Page, L.; Bennett, C. L.; Gold, B.; Jarosik, N.; Weiland, J. L.; Halpern, M.; Hill, R. S.; Kogut, A.; Limon, M.; Meyer, S. S.; Tucker, G. S.; Wollack, E.; Wright, E. L.; Komatsu, Eiichiro
This paper focuses on cosmological constraints derived from analysis of WMAP data alone. A simple Lambda CDM cosmological model fits the five-year WMAP temperature and polarization data. The basic parameters of the model are consistent with the three-year data and now better constrained: Omega(b)h(2) = 0.02273 +/- 0.00062, Omega(c)h(2) = 0.1099 +/- 0.0062, Omega(Lambda) = 0.742 +/- 0.030, n(s) = 0.963(-0.015)(+0.014), tau = 0.087 +/- 0.017, and sigma(8) = 0.796 +/- 0.036, with h = 0.719(-0.027)(+0.026). With five years of polarization data, we have measured the optical depth to reionization, tau > 0, at 5 sigma significance. The redshift of an instantaneous reionization is constrained to be z(reion) = 11.0 +/- 1.4 with 68% confidence. The 2 sigma lower limit is zreion > 8.2, and the 3 sigma limit is z(reion) > 6.7. This excludes a sudden reionization of the universe at z = 6 atmore than 3.5 sigma significance, suggesting that reionization was an extended process. Using two methods for polarized foreground cleaning we get consistent estimates for the optical depth, indicating an error due to the foreground treatment of tau similar to 0.01. This cosmological model also fits small-scale cosmic microwave background (CMB) data, and a range of astronomical data measuring the expansion rate and clustering of matter in the universe. We find evidence for the first time in the CMB power spectrum for a nonzero cosmic neutrino background, or a background of relativistic species, with the standard three light neutrino species preferred over the best-fit Lambda CDM model with N-eff = 0 at > 99.5% confidence, and N-eff > 2.3 (95% confidence limit (CL)) when varied. The five-year WMAP data improve the upper limit on the tensor-to-scalar ratio, r < 0.43 (95% CL), for power-law models, and halve the limit on r for models with a running index, r < 0.58 (95% CL). With longer integration we find no evidence for a running spectral index, with dn(s)/d ln k = -0.037 +/- 0.028, and find improved limits on isocurvature fluctuations. The current WMAP-only limit on the sum of the neutrino masses is Sigma m(v) < 1.3 eV (95% CL), which is robust, to within 10%, to a varying tensor amplitude, running spectral index, or dark energy equation of state.
The Herschel Stripe 82 Survey (HerS): Maps and Early Catalog
(2014-02) Viero, M. P.; Asboth, V.; Roseboom, I. G.; Moncelsi, L.; Marsden, G.; Cooper, E. Mentuch; Zemcov, M.; Addison, G.; Baker, A. J.; Beelen, A.; Bock, J.; Bridge, C.; Conley, A.; Devlin, M. J.; Dore, O.; Farrah, D.; Finkelstein, S.; Font-Ribera, A.; Geach, J. E.; Gebhardt, Karl; Gill, A.; Glenn, Jason; Hajian, A.; Halpern, M.; Jogee, S.; Kurczynski, P.; Lapi, A.; Negrello, M.; Oliver, S. J.; Papovich, C.; Quadri, R.; Ross, N.; Scott, D.; Schulz, B.; Somerville, R.; Spergel, D. N.; Vieira, J. D.; Wang, L.; Wechsler, R.; Cooper, E. Mentuch; Finkelstein, S.; Jogee, S.
We present the first set of maps and band-merged catalog from the Herschel Stripe 82 Survey (HerS). Observations at 250, 350, and 500 mu m were taken with the Spectral and Photometric Imaging Receiver instrument aboard the Herschel Space Observatory. HerS covers 79 deg(2) along the SDSS Stripe 82 to an average depth of 13.0, 12.9, and 14.8 mJy beam(-1) (including confusion) at 250, 350, and 500 mu m, respectively. HerS was designed to measure correlations with external tracers of the dark matter density field-either point-like (i.e., galaxies selected from radio to X-ray) or extended (i.e., clusters and gravitational lensing)-in order to measure the bias and redshift distribution of intensities of infrared-emitting dusty star-forming galaxies and active galactic nuclei. By locating HerS in Stripe 82, we maximize the overlap with available and upcoming cosmological surveys. The band-merged catalog contains 3.3 x 10(4) sources detected at a significance of >= 3 sigma (including confusion noise). The maps and catalog are available at http://www.astro.caltech.edu/hers/.
The HETDEX Pilot Survey. I. Survey Design, Performance, and Catalog of Emission-Line Galaxies
(2011-01) Adams, Joshua J.; Blanc, Guillermo A.; Hill, Gary J.; Gebhardt, Karl; Drory, Niv; Hao, Lei; Bender, Ralf; Byun, Joyce; Ciardullo, Robin; Cornell, Mark E.; Finkelstein, Steven L.; Fry, Alex; Gawiser, Eric; Gronwall, Caryl; Hopp, Ulrich; Jeong, Donghui; Kelz, Andreas; Kelzenberg, Ralf; Komatsu, Eiichiro; MacQueen, Phillip J.; Murphy, Jeremy; Odoms, P. Samuel; Roth, Martin; Schneider, Donald P.; Tufts, Joseph R.; Wilkinson, Christopher P.; Hill, Gary J.; Cornell, Mark E.; MacQueen, Phillip J.; Odoms, P. Samuel; Tufts, Joseph R.; Wilkinson, Christopher P.
We present a catalog of emission-line galaxies selected solely by their emission-line fluxes using awide-field integral field spectrograph. This work is partially motivated as a pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment. We describe the observations, reductions, detections, redshift classifications, line fluxes, and counterpart inFormation for 397 emission-line galaxies detected over 169 square' with a 3500-5800 angstrom bandpass under 5 angstrom full-width-half-maximum (FWHM) spectral resolution. The survey's best sensitivity for unresolved objects under photometric conditions is between 4 and 20 x 10(-17) erg s(-1) cm(-2) depending on the wavelength, and Ly alpha luminosities between 3 x 10(42) and 6 x 10(42) erg s(-1) are detectable. This survey method complements narrowband and color-selection techniques in the search of high-redshift galaxies with its different selection properties and large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS, and XMM-LSS areas are rich with existing, complementary data. We find 105 galaxies via their high-redshift Lya emission at 1.9 < z < 3.8, and the majority of the remainder objects are low-redshift [O II] 3727 emitters at z < 0.56. The classification between low-and high-redshift objects depends on rest-frame equivalent width (EW), as well as other indicators, where available. Based on matches to X-ray catalogs, the active galactic nuclei fraction among the Ly alpha emitters is 6%. We also analyze the survey's completeness and contamination properties through simulations. We find five high-z, highly significant, resolved objects with FWHM sizes >44 square '' which appear to be extended Ly alpha nebulae. We also find three high-z objects with rest-frame Ly alpha EW above the level believed to be achievable with normal star Formation, EW0 > 240 angstrom. Future papers will investigate the physical properties of this sample.
The HETDEX Pilot Survey. IV. The Evolution Of O II Emitting Galaxies From Z Similar To 0.5 To Z Similar To 0
(2013-05) Ciardullo, Robin; Gronwall, Caryl; Adams, Joshua J.; Blanc, Guillermo A.; Gebhardt, Karl; Finkelstein, Steven L.; Jogee, Shardha; Hill, Gary J.; Drory, Niv; Hopp, Ulrich; Schneider, Donald P.; Zeimann, Gregory R.; Dalton, Gavin B.; Adams, Joshua J.; Blanc, Guillermo A.; Gebhardt, Karl; Finkelstein, Steven L.; Jogee, Shardha
We present an analysis of the luminosities and equivalent widths of the 284 z < 0.56 [O II]-emitting galaxies found in the 169 arcmin(2) pilot survey for the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). By combining emission-line fluxes obtained from the Mitchell spectrograph on the McDonald 2.7 m telescope with deep broadband photometry from archival data, we derive each galaxy's dereddened [O II] lambda 3727 luminosity and calculate its total star formation rate. We show that over the last similar to 5Gyr of cosmic time, there has been substantial evolution in the [O II] emission-line luminosity function, with L* decreasing by similar to 0.6 +/- 0.2 dex in the observed function, and by similar to 0.9 +/- 0.2 dex in the dereddened relation. Accompanying this decline is a significant shift in the distribution of [O II] equivalent widths, with the fraction of high equivalent-width emitters declining dramatically with time. Overall, the data imply that the relative intensity of star formation within galaxies has decreased over the past similar to 5Gyr, and that the star formation rate density of the universe has declined by a factor of similar to 2.5 between z similar to 0.5 and z similar to 0. These observations represent the first [O II]-based star formation rate density measurements in this redshift range, and foreshadow the advancements which will be generated by the main HETDEX survey.
Hubble Space Telescope Emission Line Galaxies At Z Similar To 2: The Ly Alpha Escape Fraction
(2014-11) Ciardullo, Robin; Zeimann, Gregory R.; Gronwall, Caryl; Gebhardt, Henry; Schneider, Donald P.; Hagen, Alex; Malz, A. I.; Blanc, Guillermo A.; Hill, Gary J.; Drory, Niv; Gawiser, Eric; Hill, Gary J.; Drory, Niv
We compare the H beta line strengths of 1.90 < z < 2.35 star-forming galaxies observed with the near-IR grism of the Hubble Space Telescope with ground-based measurements of Ly alpha from the HETDEX Pilot Survey and narrow-band imaging. By examining the line ratios of 73 galaxies, we show that most star-forming systems at this epoch have a Ly alpha escape fraction below similar to 6%. We confirm this result by using stellar reddening to estimate the effective logarithmic extinction of the H beta emission line (c(H beta) = 0.5) and measuring both the H beta and Ly alpha luminosity functions in a similar to 100,000 Mpc(3) volume of space. We show that in our redshift window, the volumetric Ly alpha escape fraction is at most 4.4(-1.2)(+2.1)%, with an additional systematic similar to 25% uncertainty associated with our estimate of extinction. Finally, we demonstrate that the bulk of the epoch's star-forming galaxies have Ly alpha emission line optical depths that are significantly greater than that for the underlying UV continuum. In our predominantly [O-III] lambda 5007- selected sample of galaxies, resonant scattering must be important for the escape of Ly alpha photons.