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  1. METALLICITIES, DUST, AND MOLECULAR CONTENT OF A QSO-DAMPED Ly{alpha} SYSTEM REACHING log N(H I) = 22: AN ANALOG TO GRB-DLAs

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, R. [Programa de Modelagem Computacional-SENAI-Cimatec, 41650-010 Salvador, Bahia (Brazil); Noterdaeme, P.; Petitjean, P. [UPMC-CNRS, UMR7095, Institut d' Astrophysique de Paris, 98bis Blvd. Arago, F-75014 Paris (France); Ledoux, C. [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago 19 (Chile); Srianand, R.; Rahmani, H. [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India); Lopez, S., E-mail: rguimara@eso.org [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)

    2012-06-15

    We present the elemental abundance and H{sub 2} content measurements of a damped Ly{alpha} (DLA) system with an extremely large H I column density, log N(H I) (cm{sup -2}) = 22.0 {+-} 0.10, at z{sub abs} = 3.287 toward the QSO SDSS J081634+144612. We measure column densities of H{sub 2}, C I, C I*, Zn II, Fe II, Cr II, Ni II, and Si II from a high signal-to-noise and high spectral resolution VLT-UVES spectrum. The overall metallicity of the system is [Zn/H] = -1.10 {+-} 0.10 relative to solar. Two molecular hydrogen absorption components are seen at z = 3.28667 and 3.28742 (a velocity separation of Almost-Equal-To 52 km s{sup -1}) in rotational levels up to J = 3. We derive a total H{sub 2} column density of log N(H{sub 2}) (cm{sup -2}) = 18.66 and a mean molecular fraction of f = 2N(H{sub 2})/[2N(H{sub 2}) + N(H I)] = 10{sup -3.04{+-}0.37}, typical of known H{sub 2}-bearing DLA systems. From the observed abundance ratios we conclude that dust is present in the interstellar medium of this galaxy, with an enhanced abundance in the H{sub 2}-bearing clouds. However, the total amount of dust along the line of sight is not large and does not produce any significant reddening of the background QSO. The physical conditions in the H{sub 2}-bearing clouds are constrained directly from the column densities of H{sub 2} in different rotational levels, C I and C I*. The kinetic temperature is found to be T Almost-Equal-To 75 K and the particle density lies in the range n{sub H} = 50-80 cm{sup -3}. The neutral hydrogen column density of this DLA is similar to the mean H I column density of DLAs observed at the redshift of {gamma}-ray bursts (GRBs). We explore the relationship between GRB-DLAs and the high column density end of QSO-DLAs finding that the properties (metallicity and depletion) of DLAs with log N(H I) > 21.5 in the two populations do not appear to be significantly different.

  2. Molecular hydrogen, deuterium and metal abundances in the damped Ly-alpha system at z = 3.025 toward QSO 0347-3819

    CERN Document Server

    Levshakov, S A; D'Odorico, S; Molaro, P

    2001-01-01

    We have detected in high resolution spectra of the quasar Q0347-3819 obtained with the UVES spectrograph at the VLT/Kueyen telescope over 80 absorption features in the Lyman and Werner H2 bands at the redshift of a damped Ly-alpha system at z = 3.025. At the same redshift, numerous absorption lines of atoms and low ions were identified. The z = 3.025 system spans over 80 km/s and exhibits a multicomponent velocity structure in the metal lines. The main component shows a total H2 column density of (3.4 +/- 0.4) 10^{14} cm^{-2} and a fractional molecular abundance f(H2) = (1.6 +/- 0.4) 10^{-6} derived from the H2 lines arising from J = 0 to 5 rotational levels of the ground electronic - vibrational state. In the second strong component we are able to set a stringent upper limit to f(H2) of 10^{-8} (3sigma). The population of the J levels can be represented by a single excitation temperature of 808 +/- 195 K. The ortho:para-H2 ratio equals 2.7 +/- 0.5. This ratio is comparable to that calculated from hot H2 form...

  3. The size and geometry of the $Ly\\alpha$ clouds

    CERN Document Server

    D'Odorico, V; D'Odorico, S; Fontana, A; Giallongo, E; Shaver, P A

    1998-01-01

    Spectra of the QSO pair Q0307-195A,B have been obtained in the Ly-alpha forest (3660 - 3930 A) and C IV (4720 - 4850 A) regions with a FWHM resolution between 0.7 and 0.5 A. 46 lines have been detected in the spectrum of object A while 36 in the spectrum of object B, of them 29 and 20 were identified as Ly-alpha absorptions respectively. The present observations have been supplemented with data of comparable quality on other 7 QSO pairs available in the literature to give an enlarged sample of 217 Ly-alpha lines with rest equivalent width w_o > 0.3 A. The analysis of the hits (i.e. when an absorption line appears in both QSO spectra) and misses (i.e. when a line is seen in any of the QSO spectra, but no line is seen in the other), carried out with an improved statistical approach, indicates that the absorbers have typically a large size (h = H_0/100 km/s/Mpc, q_0 = 0.5): R = 362 h^{-1} kpc, with 95 % confidence limits 298< R <426 h^{-1} kpc and R = 412 h^{-1} kpc, with 95 % confidence limits 333< R &...

  4. No Ly α emitters detected around a QSO at z = 6.4: Suppressed by the QSO?★

    Science.gov (United States)

    Goto, Tomotsugu; Utsumi, Yousuke; Kikuta, Satoshi; Miyazaki, Satoshi; Shiki, Kensei; Hashimoto, Tetsuya

    2017-09-01

    Understanding how quasars' (QSOs') ultraviolet (UV) radiation affects galaxy formation is vital to our understanding of the reionization era. Using a custom-made narrow-band filter, NB906, on Subaru/Suprime-Cam, we investigated the number density of Ly α emitters (LAEs) around a QSO at z = 6.4. To date, this is the highest redshift narrow-band observation, where LAEs around a luminous QSO are investigated. Due to the large field of view of Suprime-Cam, our survey area is ∼5400 cMpc2, much larger than previous studies at z = 5.7 (∼200 cMpc2). In this field, we previously found a factor of 7 overdensity of Lyman break galaxies. Based on this, we expected to detect ∼100 LAEs down to NB906 = 25 ABmag. However, our 6.4 h exposure found none. The obtained upper limit on the number density of LAEs is more than an order lower than the blank fields. Furthermore, this lower density of LAEs spans a large scale of 10 pMpc across. A simple argument suggests that a strong UV radiation from the QSO can suppress star formation in haloes with Mvir < 1010 M⊙ within a pMpc from the QSO, but the deficit at the edge of the field (5 pMpc) remains to be explained.

  5. Mapping Neutral Hydrogen During Reionization with the Ly-alpha Emission from Quasar Ionization Fronts

    CERN Document Server

    Cantalupo, Sebastiano; Lilly, Simon J

    2007-01-01

    We present a new method to directly map the neutral-hydrogen distribution during the reionization epoch and to constrain the emission properties of the highest-redshift quasars (QSOs). As a tracer of HI, we propose to use the Ly-alpha radiation produced by quasar ionization fronts (I-fronts) that expand in the partially ionized intergalactic medium (IGM) before reionization is complete. These Ly-alpha photons are mainly generated by collisional excitations of hydrogen atoms in the boundary of the rapidly expanding HII region. The observable signal is produced by the part of the I-front that lies behind the QSO with respect to the observer. Combining two radiative transfer models (one for the QSO ionizing radiation and one for the Ly-alpha photons), we estimate the expected Ly-alpha spectral shape and surface brightness (SB) for a large number of configurations where we varied both the properties of the ionizing QSO and of the surrounding medium. We find that the expected signal is observable as a single (broa...

  6. Green Pea Galaxies Reveal Secrets of Ly$\\alpha$ Escape

    CERN Document Server

    Yang, Huan; Gronke, Max; Rhoads, James E; Jaskot, Anne; Zheng, Zhenya; Dijkstra, Mark

    2015-01-01

    Star-formation in galaxies generates a lot of Ly$\\alpha$ photons. Understanding the escape of Ly$\\alpha$ photons from galaxies is a key issue in studying high redshift galaxies and probing cosmic reionization with Ly$\\alpha$. To understand Ly$\\alpha$ escape, it is valuable to study analogs of high redshift Ly$\\alpha$ emitters in nearby universe. However, most nearby analogs have too small a Ly$\\alpha$ equivalent width and escape fraction compared to high redshift Ly$\\alpha$ emitters. One different group of nearby analogs are "Green Pea" galaxies, selected by their high equivalent width optical emission lines. Here we show that Green Pea galaxies have strong Ly$\\alpha$ emission lines and high Ly$\\alpha$ escape fraction (see also Henry et al. 2015), providing an opportunity to solve Ly$\\alpha$ escape problem. Green Peas have a Ly$\\alpha$ equivalent width distribution similar to high redshift Ly$\\alpha$ emitters. The Ly$\\alpha$ escape fraction correlates with many quantities of Ly$\\alpha$ profile, especially the...

  7. A Reverse Monte Carlo study of H+D Lyman alpha absorption from QSO spectra

    CERN Document Server

    Levshakov, S A; Takahara, F

    1997-01-01

    A new method based on a Reverse Monte Carlo [RMC] technique and aimed at the inverse problem in the analysis of interstellar (intergalactic) absorption lines is presented. The line formation process in chaotic media with a finite correlation length $(l > 0)$ of the stochastic velocity field (mesoturbulence) is considered. This generalizes the standard assumption of completely uncorrelated bulk motions $(l \\equiv 0)$ in the microturbulent approximation which is used for the data analysis up-to-now. It is shown that the RMC method allows to estimate from an observed spectrum the proper physical parameters of the absorbing gas and simultaneously an appropriate structure of the velocity field parallel to the line-of-sight. The application to the analysis of the H+D Ly$\\alpha$ profile is demonstrated using Burles & Tytler [B&T] data for QSO 1009+2956 where the DI Ly$\\alpha$ line is seen at $z_a = 2.504$. The results obtained favor a low D/H ratio in this absorption system, although our upper limit for the ...

  8. Extended Ly$\\alpha$ emission around quasars with eclipsing damped Ly$\\alpha$ systems

    CERN Document Server

    Fathivavsari, Hassan; Noterdaeme, Pasquier; Pâris, Isabelle; Finley, Hayley; López, Sebastian; Srianand, Raghunathan

    2016-01-01

    We present spectroscopic observations of six high redshift ($z_{\\rm em}$ $>$ 2) quasars, which have been selected for their Lyman $\\alpha$ (Ly$\\alpha$) emission region being only partially covered by a strong proximate ($z_{\\rm abs}$ $\\sim$ $z_{\\rm em}$) coronagraphic damped Ly$\\alpha$ system (DLA). We detected spatially extended Ly$\\alpha$ emission envelopes surrounding these six quasars, with projected spatial extent in the range 26 $\\le$ $d_{\\rm Ly\\alpha}$ $\\le$ 51 kpc. No correlation is found between the quasar ionizing luminosity and the Ly$\\alpha$ luminosity of their extended envelopes. This could be related to the limited covering factor of the extended gas and/or due to the AGN being obscured in other directions than towards the observer. Indeed, we find a strong correlation between the luminosity of the envelope and its spatial extent, which suggests that the envelopes are probably ionized by the AGN. The metallicity of the coronagraphic DLAs is low and varies in the range $-$1.75 $<$ [Si/H] $<...

  9. Properties of observed Ly-$\\alpha$ forest

    OpenAIRE

    Demianski, M.; Doroshkevich, A.; Turchaninov, V.

    2000-01-01

    The main observed properties of Ly-$\\alpha$ absorbers are investigated on the basis of theoretical model of formation and evolution of DM structure elements. This model is generally consistent with simulations of absorbers formation and with statistical description of structure evolution based on the Zel'dovich theory. The analysis of redshift variations of comoving linear number density of absorbers was performed in our previous paper. We show that the observed characteristics of Doppler par...

  10. The Building the Bridge survey for z=3 Ly-alpha emitting galaxies II: Completion of the survey

    CERN Document Server

    Grove, L F; Ledoux, C; Limousin, M; Møller, P; Nilsson, K; Thomsen, B

    2009-01-01

    (Abridged). We aim at bridging the gap between absorption selected and emission selected galaxies at z~3 by probing the faint end of the luminosity function of star-forming galaxies at z~3. We have performed narrow-band imaging in three fields with intervening QSO absorbers (a damped Ly$\\alpha$ absorber and two Lyman-limit systems) using the VLT. We target Ly-alpha at redshifts 2.85, 3.15 and 3.20. We find a consistent surface density of about 10 Ly-alpha-emitters per square arcmin per unit redshift in all three fields down to our detection limit of about 3x10^41 ergs s^-1. The luminosity function is consistent with what has been found by other surveys at similar redshifts. About 85% of the sources are fainter than the canonical limit of R=25.5 for most Lyman-break galaxy surveys. In none of the three fields do we detect the emission counterparts of the QSO absorbers. In particular we do not detect the counterpart of the z=2.85 damped Ly-alpha absorber towards Q2138-4427. Narrow-band surveys for Ly-alpha emit...

  11. Approximate formulation of redistribution in the Ly-alpha, Ly-beta, H-alpha system

    Science.gov (United States)

    Cooper, J.; Ballagh, R. J.; Hubeny, I.

    1989-01-01

    Simple approximate formulas are given for the coupled redistribution of Ly-alpha, Ly-beta, and H-alpha, by using well-defined approximations to an essentially exact formulation. These formulas incorporate all the essential physics including Raman scattering, lower state radiative decay, and correlated terms representing emission during a collision which must be retained in order that the emission coefficients are properly behaved in the line wings. Approximate expressions for the appropriate line broadening parameters are collected. Finally, practical expressions for the source functions are given. These are formulated through newly introduced nonimpact redistribution functions, which are shown to be reasonably approximated by existing (ordinary and generalized) redistribution functions.

  12. What causes the Ly$\\alpha$ forest, clouds or large-scale velocity fields ?

    CERN Document Server

    Kegel, W H

    1997-01-01

    We show that in stochastic large scale velocity fields superposed on the general Hubble flow, the formation of the GP-depression in QSO spectra is intimately related to the formation of the absorption-line structure usually called `Ly-alpha forest'. Therefore the HI-density in the diffuse IGM might be substaintially underestimated if one determines the GP-effect from the apparent continuum in high resolution spectra of QSOs. Our tentative calculations imply a current baryon density Omega_b h^2_{100} = 0.015 which agrees well with the baryon density determination from the deuterium abaundance measurement by Levshakov, Kegel and Takahara (the same volume).

  13. Ly$\\alpha$ and UV Sizes of Green Pea Galaxies

    CERN Document Server

    Yang, Huan; Rhoads, James E; Leitherer, Claus; Wofford, Aida; Jiang, Tianxing; Wang, Junxian

    2016-01-01

    Green Peas are nearby analogs of high-redshift Ly$\\alpha$-emitting galaxies. To probe their Ly$\\alpha$ escape, we study the spatial profiles of Ly$\\alpha$ and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on Hubble Space Telescope (HST). We extract the spatial profiles of Ly$\\alpha$ emission from their 2D COS spectra, and of UV continuum from both the 2D spectra and NUV images. The Ly$\\alpha$ emission shows more extended spatial profiles than the UV continuum in most Green Peas. The deconvolved Full Width Half Maximum (FWHM) of the Ly$\\alpha$ spatial profile is about 2 to 4 times that of the UV continuum in most cases. The Ly$\\alpha$ light shows significant offsets from the UV continuum in four galaxies and central absorption in one galaxy. We also compare the spatial profiles of Ly$\\alpha$ photons at blueshifted and redshifted velocities in eight Green Peas with sufficient data quality, and find the blue wing of the Ly$\\alpha$ line has a larger spatial extent than...

  14. The Ly$\\alpha$ emission from high-$z$ galaxies hosting strong Damped Ly$\\alpha$ systems

    CERN Document Server

    Joshi, Ravi; Noterdaeme, Pasquier; Petitjean, Patrick

    2016-01-01

    We study the average Ly$\\alpha$ emission associated with high-$z$ strong (log $N$(H I) $\\ge$ 21) damped Ly$\\alpha$ systems (DLAs). We report Ly$\\alpha$ luminosities ($L_{\\rm Ly\\alpha}$) for the full as well as various sub-samples based on $N$(H I), $z$, $(r-i)$ colours of QSOs and rest equivalent width of Si II$\\lambda$1526 line (i.e., $W_{1526}$). For the full sample, we find $L_{\\rm Ly\\alpha}$$< 10^{41} (3\\sigma)\\ \\rm erg\\ s^{-1}$ with a $2.8\\sigma$ level detection of Ly$\\alpha$ emission in the red part of the DLA trough. The $L_{\\rm Ly\\alpha}$ is found to be higher for systems with higher $W_{1526}$ with its peak, detected at $\\geq 3\\sigma$, redshifted by about 300-400 $\\rm km\\ s^{-1}$ with respect to the systemic absorption redshift, as seen in Lyman Break Galaxies (LBGs) and Ly$\\alpha$ emitters. A clear signature of a double-hump Ly$\\alpha$ profile is seen when we consider $W_{1526} \\ge 0.4$ \\AA\\ and $(r-i) < 0.05$. Based on the known correlation between metallicity and $W_{1526}$, we interpret our...

  15. Properties of observed Ly-$\\alpha$ forest

    CERN Document Server

    Demianski, M; Turchaninov, V I

    2000-01-01

    The main observed properties of Ly-$\\alpha$ absorbers are investigated on the basis of theoretical model of formation and evolution of DM structure elements. This model is generally consistent with simulations of absorbers formation and with statistical description of structure evolution based on the Zel'dovich theory. The analysis of redshift variations of comoving linear number density of absorbers was performed in our previous paper. We show that the observed characteristics of Doppler parameter can be related to the size of DM structure elements what allows us to explain the observed distribution of Doppler parameter. This distribution is found to be consistent with the Gaussian initial perturbations. The observed characteristics of entropy and column density, $N_{HI}$, confirm that merging of pancakes is the main evolutionary process at redshifts $z\\geq 2$. The observed sample of absorbers characterizes mainly the matter distribution within large low density regions and therefore it is difficult to recon...

  16. WARM GAS IN THE VIRGO CLUSTER. I. DISTRIBUTION OF Ly{alpha} ABSORBERS

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Joo Heon; Putman, Mary E.; Bryan, Greg L. [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Thom, Christopher [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21211 (United States); Chen, Hsiao-Wen, E-mail: jhyoon@astro.columbia.edu [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States)

    2012-08-01

    The first systematic study of the warm gas (T = 10{sup 4-5} K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Ly{alpha} absorbers (N{sub HI} = 10{sup 13.1-15.4} cm{sup -2}) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Cosmic Origin Spectrograph, with a cluster impact parameter range of 0.36-1.65 Mpc (0.23-1.05 R{sub vir}). Including 18 Ly{alpha} absorbers previously detected by STIS or GHRS toward 7 of 11 background QSOs in and around the Virgo Cluster, we establish a sample of 43 absorbers toward a total of 23 background probes for studying the incidence of Ly{alpha} absorbers in and around the Virgo Cluster. With these absorbers, we find (1) warm gas is predominantly in the outskirts of the cluster and avoids the X-ray-detected hot intracluster medium (ICM). Also, Ly{alpha} absorption strength increases with cluster impact parameter. (2) Ly{alpha}-absorbing warm gas traces cold H I-emitting gas in the substructures of the Virgo Cluster. (3) Including the absorbers associated with the surrounding substructures, the warm gas covering fraction (100% for N{sub HI} > 10{sup 13.1} cm{sup -2}) is in agreement with cosmological simulations. We speculate that the observed warm gas is part of large-scale gas flows feeding the cluster both in the ICM and galaxies.

  17. H-alpha Imaging with HST+NICMOS of An Elusive Damped Ly-alpha Cloud at z=0.6

    CERN Document Server

    Bouche, N; Charlton, J C; Bershady, M A; Churchill, C W; Steidel, C C; Bouche, Nicolas; Lowenthal, James D.; Charlton, Jane C.; Bershady, Matthew A.; Churchill, Christopher W.; Steidel, Charles C.

    2000-01-01

    Despite previous intensive ground--based imaging and spectroscopic campaigns and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts the damped Ly-alpha system along this line--of--sight has eluded detection. We present a deep narrow-band H-alpha image of the field of this z=0.656 damped Ly-alpha absorber, obtained through the F108N filter of NICMOS 1 onboard the Hubble Space Telescope. The goal of this project was to detect any H-alpha emission 10 times closer than previous studies to unveil the damped absorber. We do not detect H-alpha emission between 0.05'' and 6'' (0.24 and 30 $h^{-1}$ kpc) from the QSO, with a 3-sigma flux limit of $3.70 \\times 10^{-17} h^{-2}$ erg/s/cm^2 for an unresolved source, corresponding to a star formation rate (SFR) of $0.3 h^{-2}$ M_sun/yr. This leads to a 3-sigma upper limit of 0.15 M_sun/yr/kpc^2 on the SFR density, or a maximum SFR of 1.87 M_sun/yr assuming a disk of 4 kpc in diameter. This result adds to the number of low redshift damped Ly-alpha ab...

  18. Ly\\alpha\\ emission line reconstruction for high-$z$ QSOs

    CERN Document Server

    Greig, Bradley; McGreer, Ian D; Gallerani, Simona; Haiman, Zoltán

    2016-01-01

    We introduce an intrinsic Ly\\alpha\\ emission line profile reconstruction method for high-$z$ quasars (QSOs). This approach utilises a covariance matrix of emission line properties obtained from a large, moderate-$z$ ($2 \\leq z \\leq 2.5$), high signal to noise (S/N > 15) sample of BOSS QSOs. For each QSO, we complete a Monte Carlo Markov Chain fitting of the continuum and emission line properties and perform a visual quality assessment to construct a large database of robustly fit spectra. With this dataset, we construct a covariance matrix to describe the correlations between the high ionisation emission lines Ly\\alpha, C IV, Si IV + O IV] and C III], and find it to be well approximated by an $N$-dimensional Gaussian distribution. This covariance matrix characterises the correlations between the line width, peak height and velocity offset from systemic while also allowing for the existence of broad and narrow line components for Ly\\alpha\\ and C IV. We illustrate how this covariance matrix allows us to statist...

  19. Studying Reionization with Ly-alpha Emitters

    CERN Document Server

    McQuinn, Matthew; Zaldarriaga, Matias; Dutta, Suvendra

    2007-01-01

    We show that observations of high-redshift Ly-alpha emitters (LAEs) have the potential to provide definitive evidence for reionization in the near future. Using 200 Mpc radiative transfer simulations, we calculate the effect that patchy reionization has on the line profile, on the luminosity function, and, most interestingly, on the clustering of emitters for several realistic models of reionization. Reionization increases the measured clustering of emitters, and we show that this enhancement would be essentially impossible to attribute to anything other than reionization. Our results motivate looking for the signature of reionization in existing LAE data. We find that for stellar reionization scenarios the angular correlation function of the 58 LAEs in the Subaru Deep Field z = 6.6 photometric sample is more consistent with a fully ionized universe (mean volume ionized fraction x_i = 1) than a universe with x_i 2-sigma confidence level. Measurements in the next year on Subaru will increase their z = 6.6 LAE ...

  20. A Faraday rotation search for magnetic fields in quasar damped Ly alpha absorption systems

    Science.gov (United States)

    Oren, Abraham L.; Wolfe, Arthur M.

    1995-01-01

    We present the results of a Faraday rotation survey of 61 radio-bright QSOs conducted at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA). The Galactic contribution to the Faraday rotation is estimated and subtracted to determine the extragalactic rotation measure (RRM) for each source. Eleven of these QSOs are known to exhibit damped Ly alpha absorption. The rate of incidence of significant Faraday rotation of these 11 sources is compared to the remaining 50 and is found to be higher at the 99.8% confidence level. However, as this is based upon only two detections of Faraday rotation in the damped Ly alpha sample, the result is only tentative. If the two detections in the damped Ly alpha sample are dug to the absorbing systems, then the inferred rotation measure induced by these systems is roughly 250 rad/sq m. The two detections were for the two lowest redshift absorbers in the sample. We find that a rotation measure of 250 rad/sq m would have gone undetected for any other absorber in the damped Ly alpha sample due to the 1/(1 + 2) squared dilution of the observed RRM with redshift. Thus the data are consistent with, but do not prove, the hypothesis that Faraday rotation is a generic property of damped Ly alpha absorbers. We do not confirm the suggestion that the amplitude of RRMs increases with redshift. Rather, the data are consistent with no redshift evolution. We find that the uncertainty in the estimation of the Galactic rotation measure (GRM) is a more serious problem than previously realized for extra-galactic Faraday rotation studies of QSO absorbers. A careful analysis of current methods for estimating GRM indicate that it can be determined to an accuracy of about 15 - 20 rad/sq m. Previous studies underestimated this uncertainty by more than a factor of 2. Due to this uncertainty, rotation measures such as we suspect are associated with damped Ly alpha absorption systems can only be detected at redshifts less than z approximately

  1. Modelling the Evolution of Ly$\\alpha$ Blobs and Ly$\\alpha$ Emitters

    CERN Document Server

    Smailagić, Marijana; Martinovic, Nemanja

    2016-01-01

    In this work we model the observed evolution in comoving number density of Lyman-alpha blobs (LABs) as a function of redshift, and try to find which mechanism of emission is dominant in LAB. Our model calculates LAB emission both from cooling radiation from the intergalactic gas accreting onto galaxies and from star formation (SF). We have used dark matter (DM) cosmological simulation to which we applied empirical recipes for Ly$\\alpha$ emission produced by cooling radiation and SF in every halo. In difference to the previous work, the simulated volume in the DM simulation is large enough to produce an average LABs number density. At a range of redshifts $z\\sim 1-7$ we compare our results with the observed luminosity functions of LABs and LAEs. Our cooling radiation luminosities appeared to be too small to explain LAB luminosities at all redshifts. In contrast, for SF we obtained a good agreement with observed LFs at all redshifts studied. We also discuss uncertainties which could influence the obtained resul...

  2. The Subaru Ly-alpha blob survey: A sample of 100 kpc Ly-alpha blobs at z=3

    CERN Document Server

    Matsuda, Y; Hayashino, T; Yamauchi, R; Nakamura, Y; Morimoto, N; Ouchi, M; Ono, Y; Kousai, K; Nakamura, E; Horie, M; Fujii, T; Umemura, M; Mori, M

    2010-01-01

    We present results of a survey for giant Ly-alpha nebulae (LABs) at z=3 with Subaru/Suprime-Cam. We obtained Ly-alpha imaging at z=3.09+-0.03 around the SSA22 protocluster and in several blank fields. The total survey area is 2.1 square degrees, corresponding to a comoving volume of 1.6 x 10^6 Mpc^3. Using a uniform detection threshold of 1.4 x 10^{-18} erg s^{-1} cm^{-2} arcsec^{-2} for the Ly-alpha images, we construct a sample of 14 LAB candidates with major-axis diameters larger than 100 kpc, including five previously known blobs and two known quasars. This survey triples the number of known LABs over 100 kpc. The giant LAB sample shows a possible "morphology-density relation": filamentary LABs reside in average density environments as derived from compact Ly-alpha emitters, while circular LABs reside in both average density and overdense environments. Although it is hard to examine the formation mechanisms of LABs only from the Ly-alpha morphologies, more filamentary LABs may relate to cold gas accretion...

  3. Observational challenges in Ly-alpha intensity mapping

    CERN Document Server

    Comaschi, Paolo; Ferrara, Andrea

    2016-01-01

    Intensity mapping (IM) is sensitive to the cumulative line emission of galaxies. As such it represents a promising technique for statistical studies of galaxies fainter than the limiting magnitude of traditional galaxy surveys. The strong hydrogen Ly-alpha line is the primary target for such an experiment, as its intensity is linked to star formation activity and the physical state of the interstellar (ISM) and intergalactic (IGM) medium. However, to extract the meaningful information one has to solve the confusion problems caused by interloping lines from foreground galaxies. We discuss here the challenges for a Ly-alpha IM experiment targeting z > 4 sources. We find that the Ly-alpha power spectrum can be in principle easily (marginally) obtained with a 40 cm space telescope in a few days of observing time up to z < 8 (z = 10) assuming that the interloping lines (e.g. H-alpha, [O II], [O III] lines) can be efficiently removed. We show that interlopers can be removed by using an ancillary photometric gala...

  4. Voids in Ly{\\alpha} Forest Tomographic Maps

    CERN Document Server

    Stark, Casey W; White, Martin; Lee, Khee-Gan

    2015-01-01

    We present a new method of finding cosmic voids using tomographic maps of Ly{\\alpha} forest flux. We identify cosmological voids with radii of 2 - 12 $h^{-1}$Mpc in a large N-body simulation at $z = 2.5$, and characterize the signal of the high-redshift voids in density and Ly{\\alpha} forest flux. The void properties are similar to what has been found at lower redshifts, but they are smaller and have steeper radial density profiles. Similarly to what has been found for low-redshift voids, the radial velocity profiles have little scatter and agree very well with the linear theory prediction. We run the same void finder on an ideal Ly{\\alpha} flux field and tomographic reconstructions at various spatial samplings. We compare the tomographic map void catalogs to the density void catalog and find good agreement even with modest-sized voids ($r > 6 \\, h^{-1}$Mpc). Using our simple void-finding method, the configuration of the ongoing CLAMATO survey covering 1 deg$^2$ would provide a sample of about 100 high-redshi...

  5. Search for alpha variation in UVES spectra: Analysis of C IV and Si IV doublets towards QSO 1101-264

    Science.gov (United States)

    Martínez Fiorenzano, A. F.; Vladilo, G.; Bonifacio, P.

    Motivated by previous studies of QSO spectra that reported a variation of the fine structure constant alpha , a search for C IV and Si IV doublets was conducted in the absorption spectrum toward QSO 1101-264, obtained by VLT-UVES during the Science Verification. Seven C IV and two Si IV systems were identified and accurate measurements of wavelengths over the redshift range 1.1862 < z < 1.8377 were performed. After a careful selection of pairs of lines, the ``Alkali Doublet" method with a derived analitical expression for the error analysis was applied to compute the alpha variation. The result according in magnitud order with previous doublets measurements, corresponds to one Si IV system: Delta alpha /alpha = (- 3.09 +/- 8.46) x 10-5. Data from UVES-VLT.

  6. Search for alpha variation in UVES spectra: Analysis of C IV and Si IV doublets towards QSO 1101-264

    CERN Document Server

    Fiorenzano, A F M; Bonifacio, P

    2003-01-01

    Motivated by previous studies of QSO spectra that reported a variation of the fine structure constant alpha, a search for C IV and Si IV doublets was conducted in the absorption spectrum towardS QSO 1101-264, obtained by VLT-UVES during the Science Verification. Seven C IV and two Si IV systems were identified and accurate measurements of wavelengths over the redshift range 1.1862 < z < 1.8377 were performed. After a careful selection of pairs of lines, the "Alkali Doublet" method with a derived analitical expression for the error analysis was applied to compute the alpha variation. The result according in magnitud order with previous doublets measurements, corresponds to one Si IV system: Delta alpha/alpha = (- 3.09 +/- 8.46) x 10^(-5).

  7. Ly$\\alpha$ Emitters with Very Large Ly$\\alpha$ Equivalent Widths, EW$_{\\rm 0}$(Ly$\\alpha$) $\\simeq 200-400$ \\AA, at $z\\sim 2$

    CERN Document Server

    Hashimoto, Takuya; Shimasaku, Kazuhiro; Schaerer, Daniel; Nakajima, Kimihiko; Shibuya, Takatoshi; Ono, Yoshiaki; Rauch, Michael; Goto, Ryosuke

    2016-01-01

    We present physical properties of spectroscopically confirmed Ly$\\alpha$ emitters (LAEs) with very large rest-frame Ly$\\alpha$ equivalent widths EW$_{\\rm 0}$(Ly$\\alpha$). Although the definition of large EW$_{\\rm 0}$(Ly$\\alpha$) LAEs is usually difficult due to limited statistical and systematic uncertainties, we identify six LAEs selected from $\\sim 3000$ LAEs at $z\\sim 2$ with reliable measurements of EW$_{\\rm 0}$ (Ly$\\alpha$) $\\simeq 200-400$ \\AA\\ given by careful continuum determinations with our deep photometric and spectroscopic data. These large EW$_{\\rm 0}$(Ly$\\alpha$) LAEs do not have signatures of AGN, but notably small stellar masses of $M_{\\rm *} = 10^{7-8}$ $M_{\\rm \\odot}$ and high specific star-formation rates (star formation rate per unit galaxy stellar mass) of $\\sim 100$ Gyr$^{-1}$. These LAEs are characterized by the median values of $L({\\rm Ly\\alpha})=3.7\\times 10^{42}$ erg s$^{-1}$ and $M_{\\rm UV}=-18.0$ as well as the blue UV continuum slope of $\\beta = -2.5\\pm0.2$ and the low dust extinc...

  8. XMM-Newton Observation of Fe K(alpha) Emission from a BAL QSO: Mrk 231

    Science.gov (United States)

    Turner, T. J.; Kraemer, S. B.

    2003-01-01

    We present results from a 20 ksec XMM-Newton observation of Mrk 231. EPIC spectral data reveal strong line emission due to Fe K alpha, which has rarely been detected in this class, as BAL QSOs are very faint in the X-ray band. The line energy is consistent with an origin in neutral Fe. The width of the line is equivalent to a velocity dispersion approximately 18,000 kilometers per second and thus the line may be attributed to transmission and/or reflection from a distribution of emitting clouds. If, instead, the line originates in the accretion disk then the line strength and flat X-ray continuum support some contribution from a reflected component, although the data disfavor a model where the hard X-ray band is purely reflected X-rays. The line parameters are similar to those obtained for the Fe Ka line detected in another BAL QSO, H1413 + 117.

  9. Linking Ly-alpha and Low-Ionization Transitions at Low Optical Depth

    CERN Document Server

    Jaskot, A E

    2014-01-01

    We suggest that low optical depth in the Lyman continuum (LyC) may relate the Ly-alpha emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope COS spectra of four Green Pea (GP) galaxies, which may be analogs of z>2 Ly-alpha emitters (LAEs). In the two GPs with the strongest Ly-alpha emission, the Ly-alpha line profiles do not show the typical effects of resonant scattering. Instead, the Ly-alpha profiles resemble the H-alpha line profiles of evolved star ejecta, suggesting that the Ly-alpha emission originates from a low column density and similar outflow geometry. The weak C II absorption and presence of non-resonant C II* emission in these GPs support this interpretation and imply a low LyC optical depth along the line of sight. In two additional GPs, weak Ly-alpha emission and strong C II absorption suggest a higher optical depth. These two GPs differ in their Ly-alpha profile shapes and C II* emission strengths, ho...

  10. Extinction Correction Significantly Influences the Estimate of Ly$\\alpha$ Escape Fraction

    CERN Document Server

    An, Fangxia; HAO, Cai-Na; Huang, Jia-Sheng; Xia, Xiao-Yang

    2016-01-01

    The Ly$\\alpha$ escape fraction is a key measure to constraining the neutral state of the inter-galactic medium and then to understanding how the universe was fully reionized. We combine deep narrow-band imaging data through the custom-made filter NB393 and the $H_{2}S$1 filter centered at 2.14 $\\mu$m to examine the Ly$\\alpha$ emitters and H$\\alpha$ emitters at the same redshift $z=2.24$. The combination of two populations allows us to determine the Ly$\\alpha$ escape fraction at $z=2.24$. Over an area of 383 arcmin$^{2}$ in the Extended Chandra Deep Field (ECDFS), 124 Ly$\\alpha$ emitters are detected down to NB393 = 26.4 mag at the 5$\\sigma$ level and 56 H$\\alpha$ emitters from An14. Of them, four have both Ly$\\alpha$ and H$\\alpha$ emissions (LAHAEs). We measure the individual/volumetric Ly$\\alpha$ escape fraction by comparing the observed Ly$\\alpha$ luminosity/luminosity density to extinction-corrected H$\\alpha$ luminosity/luminosity density. We revisit the extinction correction for H$\\alpha$ emitters using t...

  11. Strong Ly$\\alpha$ Emission in the Proximate Damped Ly$\\alpha$ Absorption Trough toward the Quasar SDSS J095253.83$+$011422.0

    CERN Document Server

    Jiang, Peng; Pan, Xiang; Jiang, Ning; Shu, Xinwen; Wang, Huiyuan; Gu, Qiusheng; Li, Zhenzhen; Wu, Maochun; Shi, Xiheng; Ji, Tuo; Tian, Qiguo; Zhang, Shaohua

    2016-01-01

    SDSS J095253.83$+$011422.0 (SDSS J0952$+$0114) was reported by Hall et al. (2004) as an exotic quasar at $z_{em}=3.020$. In contrast to prominent broad metal--line emissions with FWHM$\\sim9000$~km~s$^{-1}$, only a narrow Ly$\\alpha$ emission line is present with FWHM$\\sim$1000~km~s$^{-1}$. The absence of broad Ly$\\alpha$ emission line has been a mystery for more than a decade. In this paper, we demonstrate that this is due to dark Proximate Damped Ly$\\alpha$ Absorption (PDLA) at $z_{abs}=3.010$ by identifying associated Lyman absorption line series from the damped Ly$\\beta$ up to Ly9, as well as the Lyman limit absorption edge. The PDLA cloud has a column density of $\\log N_{\\rm H\\,I}({\\rm cm}^{-2})=21.8\\pm0.2$, a metallicity of [Zn/H]$>-1.0$, and a spatial extent exceeding the Narrow Emission Line Region (NELR) of the quasar. With a luminosity of $L_{{\\rm Ly}\\alpha}\\sim10^{45}$~erg~s$^{-1}$, the residual Ly$\\alpha$ emission superposed on the PDLA trough is of two orders of magnitude stronger than previous rep...

  12. Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149

    CERN Document Server

    Srianand, Raghunathan; Noterdaeme, Pasquier; Petitjean, Patrick; Krühler, Thomas; Japelj, Jure; Pâris, Isabelle; Kashikawa, Nobunari

    2016-01-01

    Using VLT/X-shooter we searched for emission line galaxies associated to four damped Lyman-$\\alpha$ systems (DLAs) and one sub-DLA at 2.73=10 per cent. No other emission line is detected from this system. Because the DLA has a small velocity separation from the quasar (~500 km s^{-1}) and the DLA emission is located within a small projected distance ($\\rho<5$ kpc), we also explore the possibility that the Ly$\\alpha$ emission is being induced by the QSO itself. QSO induced Ly$\\alpha$ fluorescence is possible if the DLA is within a physical separation of 340 kpc to the QSO. Detection of stellar continuum light and/or the oxygen emission lines would disfavor this possibility. We do not detect any emission line from the remaining three systems.

  13. CNO abundances in the Damped Ly-alpha clouds

    CERN Document Server

    Molaro, P

    2003-01-01

    Damped Ly alpha clouds provide information on the chemistry of distant and metal poor regions of the universe. In these clouds for observational difficulties N and O are among the last elements to be measured, and C has still to be measured with precision. In combining the extant CNO abundances, we avail of a sample which includes 33 N measurements or significant limits, a dozen of O measurements, and only few tentative measurements for C. O is found to track both S and Si rather closely without signatures of any peculiar behaviour and the few [O/Zn] ratios available show a mild alpha/iron-peak enhancement which reinforces earlier evidence. The few tentative C measurements point to roughly solar [C/Zn] and [C/Si] ratios. N abundances are rather complex with N/alpha ratios showing a bimodal distribution. The majority of the values form a first plateau at [N/Si]=-0.82 (+/- 0.13) and about 25 % form a second plateau at [N/Si]= -1.45 (+/- 0.05). The high values are at the level of the Blue Compact Dwarfs but they...

  14. Evidence for large-scale structure in the Ly alpha forest at z > 2.6

    NARCIS (Netherlands)

    Williger, GM; Smette, A; Hazard, C; Baldwin, JA; McMahon, RG

    2000-01-01

    We present a search for spatial and redshift correlations in a 2 Angstrom, resolution spectroscopic survey of the Ly alpha forest at 2.15 Ly alpha absorption-lin

  15. Ly alpha radiation from collapsing protogalaxies. I. Characteristics of the emergent spectrum

    NARCIS (Netherlands)

    Dijkstra, Mark; Haiman, Zoltan; Spaans, Marco

    2006-01-01

    We present Monte Carlo calculations of Ly alpha radiative transfer through optically thick, spherically symmetric, collapsing gas clouds. These represent simplified models of protogalaxies in the process of their assembly. Such galaxies produce Ly alpha flux over an extended solid angle, either from

  16. The matter power spectrum from the Ly alpha forest : an optical depth estimate

    NARCIS (Netherlands)

    Zaroubi, S; Nusser, A; Haehnelt, M; Kim, TS; Viel, M.

    2006-01-01

    We measure the matter power spectrum from 31 Ly alpha spectra spanning the redshift range of 1.6-3.6. The optical depth, tau, for Ly alpha absorption of the intergalactic medium is obtained from the flux using the inversion method of Nusser & Haehnelt. The optical depth is converted to density by us

  17. Ly alpha radiation from collapsing protogalaxies. I. Characteristics of the emergent spectrum

    NARCIS (Netherlands)

    Dijkstra, Mark; Haiman, Zoltan; Spaans, Marco

    2006-01-01

    We present Monte Carlo calculations of Ly alpha radiative transfer through optically thick, spherically symmetric, collapsing gas clouds. These represent simplified models of protogalaxies in the process of their assembly. Such galaxies produce Ly alpha flux over an extended solid angle, either from

  18. An 80-kpc Lyman-alpha halo around a high redshift type-2 QSO

    CERN Document Server

    Smith, Daniel J B; Simpson, Chris; Martinez-Sansigre, Alejo

    2008-01-01

    We announce the discovery of an extended emission line region associated with a high redshift type-2 QSO. The halo, which was discovered in our new wide-field narrow-band survey, resides at z = 2.85 in the Spitzer First Look Survey region and is extended over ~80 kpc. Deep VLBI observations imply that approximately 50 per cent of the radio emission is extended on scales > 200pc. The inferred AGN luminosity is sufficient to ionize the extended halo, and the optical emission is consistent with being triggered coevally with the radio source. The Lyman-alpha halo is as luminous as those found around high redshift radio galaxies, however the active nucleus is several orders of magnitude less luminous at radio wavelengths than those FRIIs more commonly associated with extended emission line regions. AMS05 appears to be a high-redshift analogue to the radio-quiet quasar E1821+643 which is core dominated but which also exhibits extended FRI-like structure and contains an optically powerful AGN. We also find evidence ...

  19. A z ~ 5.7 Ly{\\alpha} Emission Line with an Ultra Broad Red Wing

    CERN Document Server

    Yang, Huan; Zheng, Zhen-Ya; Malhotra, Sangeeta; Rhoads, James E; Infante, Leopoldo

    2014-01-01

    Using Ly{\\alpha} emission line as a tracer of high redshift star forming galaxies, hundreds of Ly{\\alpha} emission line galaxies (LAEs) at z > 5 have been detected. These LAEs are considered to be low mass young galaxies, critical to the reionization of the universe and the metal enrichment of circumgalactic medium (CGM) and intergalactic medium (IGM). It is assumed that outflows in LAEs can help ionizing photons and Ly{\\alpha} photons escape out of galaxies. However we still know little about the outflows in high redshifts LAEs due to observational difficulties, especially at redshift > 5. Models of Ly{\\alpha} radiative transfer predict asymmetric Ly{\\alpha} line profiles with broad red wing in LAEs with outflows. Here we report a z ~ 5.7 Ly{\\alpha} emission line with a broad red wing extending to > 1000 km/s relative to the peak of Ly{\\alpha} line, which has been detected in only a couple of z > 5 LAEs till now. If the broad red wing is ascribed to gas outflow instead of AGN activity, the outflow velocity c...

  20. COMPUTING INTRINSIC LY{alpha} FLUXES OF F5 V TO M5 V STARS

    Energy Technology Data Exchange (ETDEWEB)

    Linsky, Jeffrey L. [JILA, University of Colorado and NIST, 440UCB Boulder, CO 80309-0440 (United States); France, Kevin; Ayres, Tom, E-mail: jlinsky@jilau1.colorado.edu [CASA, University of Colorado, 593UCB Boulder, CO 80309-0593 (United States)

    2013-04-01

    The Ly{alpha} emission line dominates the far-ultraviolet spectra of late-type stars and is a major source for photodissociation of important molecules including H{sub 2}O, CH{sub 4}, and CO{sub 2} in exoplanet atmospheres. The incident flux in this line illuminating an exoplanet's atmosphere cannot be measured directly as neutral hydrogen in the interstellar medium (ISM) attenuates most of the flux reaching the Earth. Reconstruction of the intrinsic Ly{alpha} line has been accomplished for a limited number of nearby stars, but is not feasible for distant or faint host stars. We identify correlations connecting the intrinsic Ly{alpha} flux with the flux in other emission lines formed in the stellar chromosphere, and find that these correlations depend only gradually on the flux in the other lines. These correlations, which are based on Hubble Space Telescope spectra, reconstructed Ly{alpha} line fluxes, and irradiance spectra of the quiet and active Sun, are required for photochemical models of exoplanet atmospheres when intrinsic Ly{alpha} fluxes are not available. We find a tight correlation of the intrinsic Ly{alpha} flux with stellar X-ray flux for F5 V to K5 V stars, but much larger dispersion for M stars. We also show that knowledge of the stellar effective temperature and rotation rate can provide reasonably accurate estimates of the Ly{alpha} flux for G and K stars, and less accurate estimates for cooler stars.

  1. Ly$\\alpha$ emission from Green Peas: the role of circumgalactic gas density, covering, and kinematics

    CERN Document Server

    Henry, Alaina; Martin, Crystal; Erb, Dawn

    2015-01-01

    We report Hubble Space Telescope/Cosmic Origins Spectrograph observations of the Ly$\\alpha$ emission and interstellar absorption lines in a sample of ten star-forming galaxies at z~0.2. Selected on the basis of high equivalent width optical emission lines, the sample, dubbed "Green Peas," make some of the best analogs for young galaxies in an early Universe. We detect Ly$\\alpha$ emission in all ten galaxies, and 9/10 show double-peaked line profiles suggestive of low H I column density. We measure Ly$\\alpha$/H$\\alpha$ flux ratios of 0.5-5.6, implying that 5% to 60% of Ly$\\alpha$ photons escape the galaxies. These data confirm previous findings that low-ionization metal absorption (LIS) lines are weaker when Ly$\\alpha$ escape fraction and equivalent width are higher. However, contrary to previously favored interpretations of this trend, increased Ly$\\alpha$ output cannot be the result of a varying H I covering: the Lyman absorption lines (Ly$\\beta$ and higher) show a covering fraction near unity for gas with N...

  2. Can galactic outflows explain the properties of Ly-alpha emitters?

    CERN Document Server

    Orsi, Alvaro; Baugh, Carlton M

    2011-01-01

    We study the properties of Ly-alpha emitters in a cosmological framework by computing the escape of Ly-alpha photons through galactic outflows. We combine the GALFORM semi-analytical model of galaxy formation with a Monte Carlo Ly-alpha radiative transfer code. The properties of Ly-alpha emitters at 0Ly-alpha line profiles predicted by the two outflow geometries in terms of their width, asymmetry and shift from the line centre for a set of outflows with different hydrogen column densities, expansion velocities and metallicities. In general, the Ly-alpha line profile of the Shell geometry is broader and more asymmetric, and the Ly-alpha escape fraction is lower than with the Wind geometry for the same set of parameters. In order to implement the outflow geometries in the semi-analytical model GALFORM, a number of free parameters ...

  3. A Search for Boron in Damped Ly{\\alpha} Systems

    CERN Document Server

    Berg, Trystyn A M; Venn, Kim A; Prochaska, J Xavier

    2013-01-01

    We present the first systematic study of boron beyond the Local Group. This analysis is performed on a sample of 30 damped Ly{\\alpha} systems (DLAs) with strong metal-lines, which are expected to trace the interstellar medium of high z galaxies. We report on two boron detections at > 3{\\sigma} significance; one new detection and one confirmation. The ratios of B/O and, for the first time, B/S are compared with previous stellar and interstellar measurements in the Milky Way and Small Magellanic Cloud. The novel comparison with sulphur, which tracks oxygen's abundance, alleviates the uncertainty associated with stellar oxygen measurements. For both detections, the inferred B/S ratio is in excess of the prediction of primary boron production from spallation processes. Possible sources of contamination are discussed, as well as physical effects that could impact the observed ratios. However taken at face value, the implication of these measurements suggest potentially higher cosmic ray fluxes in DLAs. The prospec...

  4. THE FUNDAMENTAL PLANE OF DAMPED Ly{alpha} SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Neeleman, Marcel; Wolfe, Arthur M. [Department of Physics and Center for Astrophysics and Space Sciences, UCSD, La Jolla, CA 92093 (United States); Prochaska, J. Xavier [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Rafelski, Marc, E-mail: mneeleman@physics.ucsd.edu [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States)

    2013-05-20

    Using a sample of 100 H I-selected damped Ly{alpha} (DLA) systems, observed with the High Resolution Echelle Spectrometer on the Keck I telescope, we present evidence that the scatter in the well-studied correlation between the redshift and metallicity of a DLA is largely due to the existence of a mass-metallicity relationship at each redshift. To describe the fundamental relations that exist between redshift, metallicity, and mass, we use a fundamental plane description, which is described by the following equation: [M/H] = (- 1.9 {+-} 0.5) + (0.74 {+-} 0.21) {center_dot} log {Delta}v{sub 90} - (0.32 {+-} 0.06) {center_dot} z. Here, we assert that the velocity width, {Delta}v{sub 90}, which is defined as the velocity interval containing 90% of the integrated optical depth, traces the mass of the underlying dark matter halo. This description provides two significant improvements over the individual descriptions of the mass-metallicity correlation and metallicity-redshift correlation. Firstly, the fundamental equation reduces the scatter around both relationships by about 20%, providing a more stringent constraint on numerical simulations modeling DLAs. Secondly, it confirms that the dark matter halos that host DLAs satisfy a mass-metallicity relationship at each redshift between redshifts 2 through 5.

  5. The properties of Ly-alpha emitting galaxies in hierarchical galaxy formation models

    CERN Document Server

    Le Delliou, M; Baugh, C M; Morris, S L

    2006-01-01

    We present detailed predictions for the properties of Ly-alpha emitting galaxies in the framework of the LambdaCDM cosmology, calculated using the semi-analytical galaxy formation model GALFORM. We show that a simple model in which a fixed fraction of Ly-alpha photons escape from each galaxy is remarkably successful at explaining the observed luminosity function of Ly-alpha emitters over the redshift range 37, a redshift range which will be probed in the near future using new near-IR instruments such as DAzLE.

  6. The Sizes of Diffuse Ly$\\alpha$ Nebulae around Star-Forming Galaxies at High Redshift

    CERN Document Server

    Xue, Rui; Dey, Arjun; Reddy, Naveen; Hong, Sungryong; Prescott, Moire K M; Inami, Hanae; Jannuzi, Buell T; Gonzalez, Anthony H

    2016-01-01

    We report the detection of diffuse Ly$\\alpha$ emission, or Lyman alpha halos (LAHs), around star-forming galaxies at $z\\approx3.78$ and $2.66$ in the NOAO Deep Wide-Field Survey Bo\\"otes field. Our samples consist of a total of $\\approx$1,400 galaxies, within two separate regions containing spectroscopically confirmed galaxy overdensities. They provide a unique opportunity to investigate how the LAH characteristics vary with host galaxy large-scale environment and physical properties. We stack Ly$\\alpha$ images of different samples defined by these properties and measure their median LAH sizes by decomposing the stacked Ly$\\alpha$ radial profile into a compact galaxy-like and an extended halo-like component. We find that the exponential scalelength of LAHs depends on UV continuum and Ly$\\alpha$ luminosities, but not on Ly$\\alpha$ equivalent widths or galaxy overdensity parameters. The full samples, which are dominated by low UV-continuum luminosity Ly$\\alpha$ emitters ($M_{\\rm UV} \\gtrsim -21$), exhibit LAH s...

  7. Redshift distribution of {\\bf Ly-$\\alpha$} lines and metal systems

    OpenAIRE

    Demianski, M.; Doroshkevich, A. G.; Turchaninov, V.

    2000-01-01

    The observed redshift distribution of Ly-$\\alpha$ lines and metal systems is examined in order to discriminate and to trace the evolution of structure elements observed in the galaxy distribution, at small redshifts, and to test the theoretical description of structure evolution. We show that the expected evolution of filamentary component of structure describes quite well the redshift distribution of metal systems and stronger Ly-$\\alpha$ lines with $\\log(N_{HI})\\geq$14, at $z\\leq$ 3. The re...

  8. On the decreasing fraction of Strong Ly$\\alpha$ Emitters around $z$ $\\sim$ $6$-$7$

    CERN Document Server

    Sadoun, Raphael; Miralda-Escudé, Jordi

    2016-01-01

    The fraction of galaxies with strong Ly$\\alpha$ emission has been observed to decrease rapidly with redshift at $z \\ge 6$, after a gradual increase at $z6$. We study this effect by modeling the ionization and Ly$\\alpha$ radiative transfer in the infall region and the IGM around a Ly$\\alpha$ emitting galaxy (LAE), for a spherical halo model with the mean density and radial velocity profiles in the standard $\\Lambda$CDM cosmological scenario. We find that the expected fast increase of the ionizing background intensity toward the end of the reionization epoch implies a rapid evolution of halo infall regions from being self-shielded against the external ionizing background to being mostly ionized. Whereas self-shielded infall regions can scatter the Ly$\\alpha$ photons over a much larger area than the commonly used apertures for observing LAEs, the same infalling gas is no longer optically thick to the Ly$\\alpha$ emission line after it is ionized by the external background, making the Ly$\\alpha$ emission more comp...

  9. A Correlation Between Ly{\\alpha} Spectral Line Profile and Rest-Frame UV Morphology

    CERN Document Server

    U, Vivian; Darvish, Behnam; Mobasher, Bahram; Nayyeri, Hooshang; Dickinson, Mark; Stern, Daniel; Spinrad, Hyron; Mallery, Ryan

    2015-01-01

    We explore the relationship between the spectral shape of the Ly{\\alpha} emission and the UV morphology of the host galaxy using a sample of 304 Ly{\\alpha}-emitting BV i-dropouts at 3 < z < 7 in the GOODS and COSMOS fields. Using our extensive reservoir of high-quality Keck DEIMOS spectra combined with HST WFC3 data, we measure the Ly{\\alpha} line asymmetries for individual galaxies and compare them to axial ratios measured from observed J- and H-band (restframe UV) images. We find that the Ly{\\alpha} skewness exhibits a large scatter at small elongation (a/b < 2), and this scatter decreases as axial ratio increases. Comparison of this trend to radiative transfer models and various results from literature suggests that these high-redshift Ly{\\alpha} emitters are not likely to be intrinsically round and symmetric disks, but they probably host galactic outflows traced by Ly{\\alpha} emitting clouds. The ionizing sources are centrally located, with the optical depth a good indicator of the absorption and...

  10. FUV Irradiated Disk Atmospheres: Ly$\\alpha$ and the Origin of Hot H$_2$ Emission

    CERN Document Server

    Ádámkovics, Máté; Glassgold, Alfred E

    2015-01-01

    Protoplanetary disks are strongly irradiated by a stellar FUV spectrum that is dominated by Ly$\\alpha$ photons. We investigate the impact of stellar Ly$\\alpha$ irradiation on the terrestrial planet region of disks ($\\lesssim 1$AU) using an updated thermal-chemical model of a disk atmosphere irradiated by stellar FUV and X-rays. The radiative transfer of Ly$\\alpha$ is implemented in a simple approach that includes scattering by H I and absorption by molecules and dust. Because of their non-radial propagation path, scattered Ly$\\alpha$ photons deposit their energy deeper in the disk atmosphere than the radially propagating FUV continuum photons. We find that Ly$\\alpha$ has a significant impact on the thermal structure of the atmosphere. Photochemical heating produced by scattered Ly$\\alpha$ photons interacting with water vapor and OH leads to a layer of hot (1500 - 2500 K) molecular gas. The temperature in the layer is high enough to thermally excite the H$_2$ to vibrational levels from which they can be fluore...

  11. On the contribution of fluorescence to Ly$\\alpha$ halos (LAHs) around star forming galaxies

    CERN Document Server

    Mas-Ribas, Lluís

    2016-01-01

    We quantify the contribution of Ly$\\alpha$ fluorescence to observed spatially extended Ly$\\alpha$ halos around Ly$\\alpha$ emitters (LAE) at redshift ${\\rm z=3.1}$. The key physical quantities that describe the fluorescent signal include (${\\it i}$) the distribution of cold gas in the circum-galactic medium (CGM); we explore simple analytic models and fitting functions to recent hydrodynamical simulations; (${\\it ii}$) local variations in the ionizing background due to ionizing sources that cluster around the central galaxy. We account for clustering by boosting the observationally inferred volumetric production rate of ionizing photons, $\\epsilon_{\\rm LyC}$, by a factor $1+\\xi_{\\rm LyC}(r)$, in which $\\xi_{\\rm LyC}(r)$ quantifies the clustering of ionizing sources around the central galaxy. We compute $\\xi_{\\rm LyC}(r)$ by assigning an 'effective' bias parameter to the ionizing sources. This novel approach allows us to quantify our ignorance of the population of ionizing sources in a simple parametrized form....

  12. The bispectrum of the Lyman-alpha forest at z~2-2.4 from a Large sample of UVES QSO Absorption Spectra (LUQAS)

    CERN Document Server

    Viel, M; Heavens, A; Hähnelt, M G; Kim, T S; Springel, V; Hernquist, L

    2004-01-01

    We present a determination of the bispectrum of the flux in the Lyman-alpha forest of QSO absorption spectra obtained from LUQAS which consists of spectra observed with the high resolution Echelle spectrograph UVES. Typical errors on the observed bispectrum as obtained from a jack-knife estimator are ~ 50%. For wavenumbers in the range 0.03 s/km 2.

  13. Clustering of Ly alpha emitters at z approximate to 4.5

    NARCIS (Netherlands)

    Kovac, Katarina; Somerville, Rachel S.; Rhoads, James E.; Malhotra, Sangeeta; Wang, JunXian

    2007-01-01

    We present the clustering properties of 151 Ly alpha-emitting galaxies at z approximate to 4.5 selected from the Large Area Lyman Alpha (LALA) survey. Our catalog covers an area of 36'; 36' observed with five narrowband filters. We assume that the angular correlation function w(theta) is well repres

  14. Clustering of Ly alpha emitters at z approximate to 4.5

    NARCIS (Netherlands)

    Kovac, Katarina; Somerville, Rachel S.; Rhoads, James E.; Malhotra, Sangeeta; Wang, JunXian

    2007-01-01

    We present the clustering properties of 151 Ly alpha-emitting galaxies at z approximate to 4.5 selected from the Large Area Lyman Alpha (LALA) survey. Our catalog covers an area of 36'; 36' observed with five narrowband filters. We assume that the angular correlation function w(theta) is well

  15. A Deep Narrowband Imaging Search for CIV and He II Emission from Ly$\\alpha$ Blobs

    CERN Document Server

    Battaia, Fabrizio Arrigoni; Hennawi, Joseph F; Prochaska, J Xavier; Matsuda, Yuichi; Yamada, Toru; Hayashino, Tomoki

    2014-01-01

    We conduct a deep narrow-band imaging survey of 13 Ly$\\alpha$ blobs (LABs) located in the SSA22 proto-cluster at z~3.1 in the CIV and HeII emission lines in an effort to constrain the physical process powering the Ly$\\alpha$ emission in LABs. Our observations probe down to unprecedented surface brightness limits of 2.1 $-$ 3.4 $\\times$ 10$^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ per 1 arcsec$^2$ aperture (5$\\sigma$) for the HeII$\\lambda$1640 and CIV$\\lambda$1549 lines, respectively. We do not detect extended HeII and CIV emission in any of the LABs, placing strong upper limits on the HeII/Ly$\\alpha$ and CIV/Ly$\\alpha$ line ratios, of 0.11 and 0.16, for the brightest two LABs in the field. We conduct detailed photoionization modeling of the expected line ratios and find that, although our data constitute the deepest ever observations of these lines, they are still not deep enough to rule out a scenario where the Ly$\\alpha$ emission is powered by the ionizing luminosity of an obscured AGN. Our models can ac...

  16. Modeling Lyman-\\alpha\\ Forest Cross-Correlations with LyMAS

    CERN Document Server

    Lochhaas, Cassandra; Peirani, Sébastien; Dubois, Yohan; Colombi, Stéphane; Blaizot, Jérémy; Font-Ribera, Andreu; Pichon, Christophe; Devriendt, Julien

    2015-01-01

    We use the Ly-$\\alpha$ Mass Association Scheme (LyMAS; Peirani et al. 2014) to predict cross-correlations at z = 2.5 between dark matter halos and transmitted flux in the Ly-$\\alpha$ forest, and we compare these predictions to cross-correlations measured for quasars and damped Ly-$\\alpha$ systems (DLAs) from the Baryon Oscillation Spectroscopic Survey (BOSS) by Font-Ribera et al. (2012, 2013). We calibrate and test LyMAS using Horizon-AGN hydrodynamical cosmological simulations of a $(100\\ h^{-1}\\ \\rm{Mpc})^3$ comoving volume with and without AGN feedback. We apply this calibration to a $(1\\ h^{-1}\\ \\rm{Gpc})^3$ simulation realized with $2048^3$ dark matter particles for our primary predictions. In the $100\\ h^{-1}\\ \\rm{Mpc}$ box, LyMAS reproduces the halo-flux correlations computed from the full hydrodynamic gas distribution essentially perfectly. In the $1\\ h^{-1}\\ \\rm{Gpc}$ box, the amplitude of the cross-correlation tracks the halo bias as expected, and the correlation for a halo sample with a distributio...

  17. Constraint on neutrino masses from SDSS-III/BOSS Ly$\\alpha$ forest and other cosmological probes

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Lesgourgues, Julien; Rossi, Graziano; Borde, Arnaud; Viel, Matteo; Aubourg, Eric; Kirkby, David; LeGoff, Jean-Marc; Rich, James; Roe, Natalie; Ross, Nicholas P.; Schneider, Donald P.; Weinberg, David

    2015-01-01

    We present constraints on the parameters of the $\\Lambda$CDM cosmological model in the presence of massive neutrinos, using the one-dimensional Ly$\\alpha$ forest power spectrum obtained with the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS) by Palanque-Delabrouille et al. (2013), complemented by additional cosmological probes. The interpretation of the measured Ly$\\alpha$ spectrum is done using a second-order Taylor expansion of the simulated power spectrum. BOSS Ly$\\alpha$ data alone provide better bounds than previous Ly$\\alpha$ results, but are still poorly constraining, especially for the sum of neutrino masses $\\sum m_\

  18. Redshift distribution of {\\bf Ly-$\\alpha$} lines and metal systems

    CERN Document Server

    Demianski, M; Turchaninov, V I

    2000-01-01

    The observed redshift distribution of Ly-$\\alpha$ lines and metal systems is examined in order to discriminate and to trace the evolution of structure elements observed in the galaxy distribution, at small redshifts, and to test the theoretical description of structure evolution. We show that the expected evolution of filamentary component of structure describes quite well the redshift distribution of metal systems and stronger Ly-$\\alpha$ lines with $\\log(N_{HI})\\geq$14, at $z\\leq$ 3. The redshift distribution of weaker Ly-$\\alpha$ lines can be attributed to the population of poorer structure elements (Zel'dovich pancakes), which were formed at high redshifts from the invisible DM and non luminous baryonic matter, and at lower redshifts they mainly merged and dispersed.

  19. The impact of temperature fluctuations on the large scale clustering of the Ly$\\alpha$ forest

    CERN Document Server

    Greig, Bradley; Wyithe, J Stuart B

    2014-01-01

    We develop a semi-analytic method for assessing the impact of the large scale IGM temperature fluctuations expected following He${\\rm\\,{\\scriptstyle II}}$ reionization on three dimensional clustering measurements of the Ly$\\alpha$ forest. Our methodology builds upon the existing large volume, mock Ly$\\alpha$ forest survey simulations presented by Greig et al. (2011) by including a prescription for a spatially inhomogeneous ionising background, temperature fluctuations induced by patchy He${\\rm\\,{\\scriptstyle II}}$ photo-heating and the clustering of quasars. This approach enables us to achieve a dynamic range within our semi-analytic model substantially larger than currently feasible with computationally expensive, fully numerical simulations. The results agree well with existing numerical simulations, with large scale temperature fluctuations introducing a scale dependent increase in the spherically averaged 3D Ly$\\alpha$ forest power spectrum of up to 20-30 per cent at wavenumbers $k\\sim0.02$ Mpc$^{-1}$. Al...

  20. Probing the IGM with Ly$\\mathrm{\\alpha}$ and 21 cm fluctuations

    CERN Document Server

    Heneka, Caroline; Feng, Chang

    2016-01-01

    We study 21 cm and Ly$\\mathrm{\\alpha}$ fluctuations, as well as H$\\mathrm{\\alpha}$, while distinguishing for Ly$\\mathrm{\\alpha}$ between emission of galactic, diffuse and scattered IGM origin. Cross-correlation information about the state of the IGM is worked out, testing neutral versus ionized medium with different tracers in a semi-numerical simulation setup. In order to path the way for constraints on reionization history and modelling beyond power spectrum information, we explore parameter dependencies of the cross-power signal between 21$\\,$cm and Ly$\\mathrm{\\alpha}$, which displays characteristic morphology and a turn-over from negative to positive correlation at scales of a couple Mpc$^{-1}$. In a proof of concept for the extraction of further information on the state of the IGM using different tracers, we demonstrate the usage of the 21$\\,$cm and H$\\mathrm{\\alpha}$ cross-correlation signal to determine the relative strength of galactic and IGM emission in Ly$\\mathrm{\\alpha}$. We conclude by showing th...

  1. Foreground contamination in Ly-alpha intensity mapping during the epoch of reionization

    CERN Document Server

    Gong, Yan; Cooray, Asantha; Santos, Mario G

    2013-01-01

    The intensity mapping of Ly-alpha emission during the epoch of reionization (EoR) will be contaminated by foreground emission lines from lower redshifts. We calculate the mean intensity and power spectrum of Ly-alpha emission at z~7, and estimate the uncertainties according to the relevant astrophysical processes. We find that the low-redshift emission lines from 6563 A H-alpha, 5007 A [OIII] and 3727 A [OII] will be the strong contaminants on the observed Ly-alpha power spectrum. We make use of both the star formation rate (SFR) and luminosity functions (LF) to estimate the mean intensity and power spectra of the three foreground lines at z~0.5 for H-alpha, z~0.9 for [OIII] and z~1.6 for [OII], as they will contaminate the Ly-alpha emission at z~7. The [OII] line is found to be the strongest. We analyze the masking of the bright survey pixels with a foreground line above some line intensity threshold as a way to reduce the contamination in the intensity mapping survey. We find that the foreground contaminati...

  2. A submillimeter galaxy illuminating its circumgalactic medium: Ly-alpha scattering in a cold, clumpy outflow

    CERN Document Server

    Geach, J E; Alexander, D M; Blain, A W; Bremer, M; Chapin, E L; Chapman, S C; Clements, D L; Coppin, K E K; Dunlop, J S; Farrah, D; Jenness, T; Koprowski, M P; Michalowski, M J; Robson, E I; Scott, D; Smith, D J B; Spaans, M; Swinbank, A M; van der Werf, P

    2014-01-01

    We report the detection at 850um of the central source in SSA22-LAB1, the archetypal Lyman-alpha Blob (LAB), a 100kpc-scale radio-quiet emission-line nebula at z=3.1. The flux density of the source, $S_{850}=4.6\\pm1.1$mJy implies the presence of a galaxy, or group of galaxies, with a total luminosity of $L_{\\rm IR}\\approx10^{12}L_\\odot$. The position of an active source at the center of a ~50kpc-radius ring of linearly polarized Ly-alpha emission detected by Hayes et al. (2011) suggests that the central source is leaking Ly-alpha photons preferentially in the plane of the sky, which undergo scattering in HI clouds at large galactocentric radius. The Ly-alpha morphology around the submillimeter detection is reminiscent of biconical outflow, and the average Ly-alpha line profiles of the two `lobes' are dominated by a red peak, expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evi...

  3. Hubble and FUSE studies of Ly-alpha absorbers at low redshift

    CERN Document Server

    Shull, J M

    2001-01-01

    Ultraviolet spectrographs aboard the Hubble Space Telescope (HST) and the Far Ultraviolet Spectroscopic Explorer (FUSE) have proved their value as sensitive probes of the low-density intergalactic medium (IGM) at low redshifts (z < 0.1). Recent observations in Ly-alpha, Ly-beta, and occasional higher Lyman lines show that warm photoionized gas in the low-z IGM may contain 20-25% of the baryons, with a N(HI)^-1.8 distribution in column density. Measurements of resonance lines of Si III, C III, C IV, and O VI suggest that the metallicity of these absorbers ranges from 1-10% of solar abundance down to values below 0.003 Z(solar). A comparison of Ly-beta/Ly-alpha ratios (FUSE and HST) yields a distribution of Doppler parameters with mean b = 31.4 +/- 7.4 km/s and median 28 km/s, comparable to values at z = 2-3. The curve-of-growth (CoG) b-values are considerably less than widths derived from Ly-alpha profile fitting, with mean b(CoG)/b(width) = 0.52, which suggests that low-z absorbers contain sizable non-ther...

  4. Physical properties of z~4 LBGs: differences between galaxies with and without Ly-alpha emission

    CERN Document Server

    Pentericci, L; Fontana, A; Salimbeni, S; Santini, P; De Santis, C; Gallozzi, S; Giallongo, E

    2007-01-01

    We have analysed the physical properties of z~4 Lyman Break Galaxies observed in the GOODS-S survey, in order to investigate the possible differences between galaxies where the Ly-alpha is present in emission, and those where the line is absent or in absorption. The objects have been selected from their optical color and then spectroscopically confirmed by Vanzella et al. (2005). From the public spectra we assessed the nature of the Ly-alpha emission and divided the sample into galaxies with Ly-alpha in emission and objects without Ly-alpha line (i.e. either absent or in absorption). We have then used the complete photometry, from U band to mid infrared from the GOODS-MUSIC database, to study the observational properties of the galaxies, such as UV spectral slopes and optical to mid-infrared colors, and the possible differences between the two samples. Finally through standard spectral fitting tecniques we have determined the physical properties of the galaxies, such as total stellar mass, stellar ages and so...

  5. HI column density distribution function at z=0 : Connection to damped Ly alpha statistics

    NARCIS (Netherlands)

    Zwaan, Martin; Verheijen, MAW; Briggs, FH

    We present a measurement of the HI column density distribution function f(N-HI) at the present epoch for column densities > 10(20) cm(-2). These high column densities compare to those measured in damped Ly alpha lines seen in absorption against background quasars. Although observationally rare, it

  6. HI column density distribution function at z=0 : Connection to damped Ly alpha statistics

    NARCIS (Netherlands)

    Zwaan, Martin; Verheijen, MAW; Briggs, FH

    1999-01-01

    We present a measurement of the HI column density distribution function f(N-HI) at the present epoch for column densities > 10(20) cm(-2). These high column densities compare to those measured in damped Ly alpha lines seen in absorption against background quasars. Although observationally rare, it a

  7. RESOLVING THE OPTICAL EMISSION LINES OF Ly{alpha} BLOB ''B1'' AT z = 2.38: ANOTHER HIDDEN QUASAR

    Energy Technology Data Exchange (ETDEWEB)

    Overzier, R. A. [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States); Nesvadba, N. P. H. [Institut d' Astrophysique Spatiale, CNRS, Universite Paris-Sud, F-91405 Orsay (France); Dijkstra, M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, D-85741 Garching (Germany); Hatch, N. A. [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Lehnert, M. D. [GEPI, Observatoire de Paris, UMR 8111, CNRS, Universite Paris Diderot, 5 place Jules Janssen, F-92190 Meudon (France); Villar-Martin, M. [Centro de Astrobioloia (INTA-CSIC), Carretera de Ajalvir, km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); Wilman, R. J. [Department of Physics, University of Durham, South Road, Durham DH13LE (United Kingdom); Zirm, A. W., E-mail: overzier@astro.as.utexas.edu [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2013-07-10

    We have used the SINFONI near-infrared integral field unit on the Very Large Telescope to resolve the optical emission line structure of one of the brightest (L{sub Ly{alpha}} Almost-Equal-To 10{sup 44} erg s{sup -1}) and nearest (z Almost-Equal-To 2.38) of all Ly{alpha} blobs (LABs). The target, known in the literature as object {sup B}1{sup ,} lies at a redshift where the main optical emission lines are accessible in the observed near-infrared. We detect luminous [O III] {lambda}{lambda}4959, 5007 and H{alpha} emission with a spatial extent of at least 32 Multiplication-Sign 40 kpc (4'' Multiplication-Sign 5''). The dominant optical emission line component shows relatively broad lines (600-800 km s{sup -1}, FWHM) and line ratios consistent with active galactic nucleus (AGN) photoionization. The new evidence for AGN photoionization, combined with previously detected C IV and luminous, warm infrared emission, suggest that B1 is the site of a hidden quasar. This is confirmed by the fact that [O II] is relatively weak compared with [O III] (extinction-corrected [O III]/[O II] of about 3.8), which is indicative of a high, Seyfert-like ionization parameter. From the extinction-corrected [O III] luminosity we infer a bolometric AGN luminosity of {approx}3 Multiplication-Sign 10{sup 46} erg s{sup -1}, and further conclude that the obscured AGN may be Compton-thick given existing X-ray limits. The large line widths observed are consistent with clouds moving within the narrow-line region of a luminous QSO. The AGN scenario is capable of producing sufficient ionizing photons to power the Ly{alpha}, even in the presence of dust. By performing a census of similar objects in the literature, we find that virtually all luminous LABs harbor obscured quasars. Based on simple duty-cycle arguments, we conclude that AGNs are the main drivers of the Ly{alpha} in LABs rather than the gravitational heating and subsequent cooling suggested by cold stream models. We

  8. Nitrogen Abundances in Damped Ly-alpha Absorbers

    CERN Document Server

    Zafar, Tayyaba; Molaro, Paolo; Peroux, Celine; D'Odorico, Valentina; Vladilo, Giovanni

    2014-01-01

    Nitrogen is thought to have both primary and secondary origins depending on whether the seed carbon and oxygen are produced by the star itself (primary) or already present in the interstellar medium (secondary) from which star forms. DLA and sub-DLA systems with typical metallicities of -3.0alpha-elements. This yields a total of 98 systems, i.e. the largest nitrogen abundance sample investigated so far. In agreement with previous studies, we indeed find a bimodal [N/alpha] behaviour: three-quarter systems show a mean value of [N/alpha]=-0.87 with a scatter of 0.21 dex and one-quarter shows ratios clustered at [N/alpha]=-1.43 with a lower dispersion of 0.13 dex. The high [N/alph...

  9. QSO Lifetimes

    CERN Document Server

    Martini, P

    2003-01-01

    The QSO lifetime t_Q is one of the most fundamental quantities for understanding black hole and QSO evolution, yet it remains uncertain by several orders of magnitude. If t_Q is long, then only a small fraction of galaxies went through a luminous QSO phase. In contrast, a short lifetime would require most galaxies today to have undergone a QSO phase in their youth. The current best estimates or constraints on t_Q from black hole demographics and the radiative properties of QSOs vary from at least 10^6 to 10^8 years. This broad range still allows both possibilities: that QSOs were either a rare or a common stage of galaxy evolution. These constraints also do not rule out the possibility that QSO activity is episodic, with individual active periods much shorter than the total active lifetime. In the next few years a variety of additional observational constraints on the lifetimes of QSOs will become available, including clustering measurements and the proximity effect. These new constraints can potentially dete...

  10. 3-D-geocoronal hydrogen density derived from TWINS Ly-{alpha}-data

    Energy Technology Data Exchange (ETDEWEB)

    Zoennchen, J.H.; Nass, U.; Lay, G.; Fahr, H.J. [Bonn Univ. (Germany). Argelander Inst. fuer Astronomie

    2010-07-01

    Based on Ly-{alpha}-line-of-sight measurements taken with two Ly-{alpha} detectors onboard of the satellite TWINS1 (Two Wide-angle Imaging Neutral-atom Spectrometers) density profiles of the exospheric, neutral geocoronal hydrogen were derived for the time period between summer solstice and fall equinox 2008. With the help of specifically developed inversion programs from Ly-{alpha} line of sight intensities the three-dimensional density structure of the geocoronal hydrogen at geocentric distances r > 3 R{sub E} could be derived for the period mentioned characterized by very low solar 10.7 cm radiofluxes of {approx}65-70 [10{sup -22}Wm{sup -2} Hz{sup -1}]. The time-variable, solar ''line-centered''-Ly-{alpha}-flux was extracted on the basis of daily (terrestrial) NGDC 10.7 cm radioflux data using the models from Barth et al. (1990) and Vidal- Madjar (1975). The results for the geocoronal H-densities are compared here both with theoretical calculations based on a Monte- Carlo model by Hodges (1994) and with density profiles obtained with the Geocoronal Imager (GEO) by Oestgaard and Mende (2003). In our results we find a remarkably more pronounced day-/night-side asymmetry which clearly hints to the existence of a hydrogen geotail (i.e. a tail structure with comparatively higher hydrogen densities on the night side of the earth for geocentric distances>4 R{sub E}), and a only weakly pronounced polar depletion. These unexpected features we try to explain by new models in the near future. The derived 3-D-H-density structures are able to explain the line-of-sight (LOS) dependent Ly-{alpha} intensity variations for all LOS seen up to now with TWINS-LAD. The presented results are valid for the region with geocentric distances 3 R{sub E} Ly-{alpha}-scattering allowing the use of single scattering calculations. (orig.)

  11. The transverse proximity effect in the z ~ 2 Lyman-alpha forest suggests QSO episodic lifetimes of ~1 Myr

    CERN Document Server

    Kirkman, David

    2008-01-01

    We look for signs of the H~I transverse proximity effect in the spectra of 130 QSO pairs, most with transverse separations in the plane of the sky of 0.1 -- 3 Mpc at z ~ 2.2. We expected to see a decrease in Lyman-alpha forest HI absorption in the spectrum of background QSOs near the position of foreground QSOs. Instead we see no change in the absorption in front of the foreground QSOs, and we see evidence for a 50% increase in the absorption out to 6 Mpc behind the foreground QSOs. Further, we see no change in the H I absorption along the line-of-sight to the foreground QSOs, the normal line-of-sight proximity effect. We may account for the lack of change in the H I absorption if the effect of extra UV photons is canceled by higher gas density around QSOs. If so, the increase in absorption behind the QSOs then suggests that the higher gas density there is not canceled by the UV radiation from the QSOs. We can explain our observations if QSOs have had their current UV luminosities for less than approximately ...

  12. Ly{alpha} ESCAPE FROM z {approx} 0.03 STAR-FORMING GALAXIES: THE DOMINANT ROLE OF OUTFLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Wofford, Aida; Leitherer, Claus [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Salzer, John, E-mail: wofford@stsci.edu [Astronomy Department, Indiana University, Swain West 408, 727 East Third Street, Bloomington, IN 47405 (United States)

    2013-03-10

    The usefulness of H I Ly{alpha} photons for characterizing star formation in the distant universe is limited by our understanding of the astrophysical processes that regulate their escape from galaxies. These processes can only be observed in detail out to a few Multiplication-Sign 100 Mpc. Past nearby (z < 0.3) spectroscopic studies are based on small samples and/or kinematically unresolved data. Taking advantage of the high sensitivity of Hubble Space Telescope's Cosmic Origins Spectrograph (COS), we observed the Ly{alpha} lines of 20 H{alpha}-selected galaxies located at =0.03. The galaxies cover a broad range of luminosity, oxygen abundance, and reddening. In this paper, we characterize the observed Ly{alpha} lines and establish correlations with fundamental galaxy properties. We find seven emitters. These host young ({<=}10 Myr) stellar populations have rest-frame equivalent widths in the range 1-12 A, and have Ly{alpha} escape fractions within the COS aperture in the range 1%-12%. One emitter has a double-peaked Ly{alpha} with peaks 370 km s{sup -1} apart and a stronger blue peak. Excluding this object, the emitters have Ly{alpha} and O I {lambda}1302 offsets from H{alpha} in agreement with expanding-shell models and Lyman break galaxies observations. The absorbers have offsets that are almost consistent with a static medium. We find no one-to-one correspondence between Ly{alpha} emission and age, metallicity, or reddening. Thus, we confirm that Ly{alpha} is enhanced by outflows and is regulated by the dust and H I column density surrounding the hot stars.

  13. A newly discovered DLA and associated Ly-alpha emission in the spectra of the gravitationally lensed quasar UM 673A,B

    CERN Document Server

    Cooke, Ryan; Steidel, Charles C; King, Lindsay J; Rudie, Gwen C; Rakic, Olivera

    2010-01-01

    The sightline to the brighter member of the gravitationally lensed quasar pair UM 673A,B intersects a damped Lyman-alpha system (DLA) at z = 1.62650 which, because of its low redshift, has not been recognised before. Our high quality echelle spectra of the pair, obtained with HIRES on the Keck I telescope, show a drop in neutral hydrogen column density N(H I) by a factor of at least 400 between UM 673A and B, indicating that the DLA's extent in this direction is much less than the 2.7 kpc separation between the two sightlines at z = 1.62650. By reassessing this new case together with published data on other QSO pairs, we conclude that the typical size (radius) of DLAs at these redshifts is R ~ (5 +/- 3) kpc, smaller than previously realised. Highly ionized gas associated with the DLA is more extended, as we find only small differences in the C IV absorption profiles between the two sightlines. Coincident with UM 673B, we detect a weak and narrow Ly-alpha emission line which we attribute to star formation acti...

  14. Cosmological constraints from the CMB and Ly-alpha forest revisited

    CERN Document Server

    Seljak, U; Makarov, A; Seljak, Uros; Donald, Patrick Mc; Makarov, Alexey

    2003-01-01

    The WMAP team has recently highlighted the usefulness of combining the Ly-alpha forest constraints with those from the cosmic microwave background. This combination is particularly powerful as a probe of the primordial shape of the power spectrum. Converting between the Ly-alpha forest observations and the linear mass power spectrum requires a careful treatment of nuisance parameters and modeling with cosmological simulations. We point out several errors and inconsistencies in the previous treatments that propagate into the estimations and associated errors of cosmological parameters, including those reported by the WMAP team. The two most important are the insufficient range of cosmological parameters explored in simulations used to date and an incorrect treatment of the mean transmitted flux constraints. We employ a likelihood calculator for the current data set based on an extensive 6-dimensional grid of simulations. We show that the current uncertainties in the mean transmission and the flux power spectru...

  15. Statistical characteristics of observed Ly-$\\alpha$ forest and the shape of initial power spectrum

    OpenAIRE

    Demiański, M.; Doroshkevich, A.; Turchaninov, V.

    2002-01-01

    Properties of $\\sim$ 5000 observed Ly-$\\alpha$ absorbers are investigated using the model of formation and evolution of DM structure elements based on the Zel'dovich theory. This model is generally consistent with simulations of absorbers formation, accurately describes the Large Scale Structure observed in the galaxy distribution at small redshifts and emphasizes the generic similarity of the LSS and absorbers. The simple physical model of absorbers asserts that they are composed of DM and g...

  16. VizieR Online Data Catalog: SDSS damped Ly{alpha} survey: DR1 (Prochaska+, 2004)

    Science.gov (United States)

    Prochaska, J. X.; Herbert-Fort, S.

    2005-11-01

    We present the results from an automated search for damped Ly{alpha} (DLA) systems in the quasar spectra of Data Release 1 from the Sloan Digital Sky Survey (SDSS-DR1). At z~2.5, this homogeneous data set has greater statistical significance than the previous two decades of research. We derive a statistical sample of 71 DLA systems (>50 previously unpublished) at z>2.1 and measure HI column densities directly from the SDSS spectra. (1 data file).

  17. On the effect of the ionising background on the Ly{\\alpha} forest autocorrelation function

    CERN Document Server

    Gontcho, Satya Gontcho A; Busca, Nicolás G

    2014-01-01

    An analytical framework is presented to understand the effects of a fluctuating intensity of the cosmic ionising background on the correlations of the Ly{\\alpha} forest transmission fraction measured in quasar spectra. In the absence of intensity fluctuations, the Ly{\\alpha} power spectrum should have the expected cold dark matter power spectrum with redshift distortions in the linear regime, with a bias factor b_{\\delta} and a redshift distortion parameter {\\beta} that depend on redshift but are independent of scale. The intensity fluctuations introduce a scale dependence in both b_{\\delta} and {\\beta}, but keeping their product b_{\\delta}{\\beta} fixed. Observations of the Ly{\\alpha} correlations and cross-correlations with radiation sources like those being done at present in the BOSS survey of SDSS-III (Busca et al. 2013; Slosar et al. 2013; Font-Ribera et al. 2014) have the potential to measure this scale dependence, which reflects the biasing properties of the sources and absorbers of the ionising backgr...

  18. Limits on the luminosity function of Ly-alpha emitters at z = 7.7

    CERN Document Server

    Hibon, P; Willis, J; Clément, B; Lidman, C; Arnouts, S; Kneib, J -P; Willott, C J; Marmo, C; McCracken, H

    2009-01-01

    The Ly-alpha luminosity function (LF) of high-redshift Ly-alpha emitters (LAEs) is one of the few observables of the re-ionization epoch accessible to date with 8-10 m class telescopes. The evolution with redshift allows one to constrain the evolution of LAEs and their role in re-ionizing the Universe at the end of the Dark Ages. We have performed a narrow-band imaging program at 1.06 microns at the CFHT, targeting Ly-alpha emitters at redshift z ~ 7.7 in the CFHT-LS D1 field. From these observations we have derived a photometric sample of 7 LAE candidates at z ~ 7.7. We derive luminosity functions for the full sample of seven objects and for sub-samples of four objects. If the brightest objects in our sample are real, we infer a luminosity function which would be difficult to reconcile with previous work at lower redshift. More definitive conclusions will require spectroscopic confirmation.

  19. Ly-alpha forest: efficient unbiased estimation of second-order properties with missing data

    CERN Document Server

    Vio, R; Stoyan, H; Stoyan, D

    2007-01-01

    Context. One important step in the statistical analysis of the Ly-alpha forest data is the study of their second order properties. Usually, this is accomplished by means of the two-point correlation function or, alternatively, the K-function. In the computation of these functions it is necessary to take into account the presence of strong metal line complexes and strong Ly-alpha lines that can hidden part of the Ly-alpha forest and represent a non negligible source of bias. Aims. In this work, we show quantitatively what are the effects of the gaps introduced in the spectrum by the strong lines if they are not properly accounted for in the computation of the correlation properties. We propose a geometric method which is able to solve this problem and is computationally more efficient than the Monte Carlo (MC) technique that is typically adopted in Cosmology studies. The method is implemented in two different algorithms. The first one permits to obtain exact results, whereas the second one provides approximate...

  20. Probing high-redshift galaxies with Ly$\\alpha$ intensity mapping

    CERN Document Server

    Comaschi, P

    2015-01-01

    We present a study of the cosmological Ly$\\alpha$ emission signal at $z > 4$. Our goal is to predict the power spectrum of the spatial fluctuations that could be observed by an intensity mapping survey. The model uses the latest data from the HST legacy fields and the abundance matching technique to associate UV emission and dust properties with the halos, computing the emission from the interstellar medium (ISM) of galaxies and the intergalactic medium (IGM), including the effects of reionization, self-consistently. The Ly$\\alpha$ intensity from the diffuse IGM emission is 1.3 (2.0) times more intense than the ISM emission at $z = 4(7)$; both components are fair tracers of the star-forming galaxy distribution. However the power spectrum is dominated by ISM emission on small scales ($k > 0.01 h{\\rm Mpc}^{-1}$) with shot noise being significant only above $k = 1 h{\\rm Mpc}^{-1}$. At very lange scales ($k < 0.01h{\\rm Mpc}^{-1}$) diffuse IGM emission becomes important. The comoving Ly$\\alpha$ luminosity densi...

  1. The Rest-Frame Optical Spectroscopic Properties of Ly$\\alpha$-Emitters at $z\\sim2.5$: The Physical Origins of Strong Ly$\\alpha$ Emission

    CERN Document Server

    Trainor, Ryan F; Steidel, Charles C; Rudie, Gwen C

    2016-01-01

    We present rest-frame optical spectra of 60 faint ($R_{AB}\\sim 27$; $L\\sim0.1 L_*$) Ly$\\alpha$-selected galaxies (LAEs) at $z\\approx2.56$. The average LAE is consistent with the extreme low-metallicity end of the continuum-selected galaxy distribution at $z\\approx2-3$. In particular, the LAEs have extremely high [OIII] $\\lambda$5008/H$\\beta$ ratios (log([OIII]/H$\\beta$) $\\sim$ 0.8) and low [NII] $\\lambda$6585/H$\\alpha$ ratios (log([NII]/H$\\alpha$) $<-1.15$). Using the [OIII] $\\lambda$4364 auroral line, we find that the star-forming regions in faint LAEs are characterized by high electron temperatures ($T_e\\approx1.8\\times10^4$K), low oxygen abundances (12 + log(O/H) $\\approx$ 8.04, $Z_{neb}\\approx0.22Z_\\odot$), and high excitations with respect to more luminous galaxies. Our faintest LAEs have line ratios consistent with even lower metallicities, including six with 12 + log(O/H) $\\approx$ 6.9$-$7.4 ($Z_{neb}\\approx0.02-0.05Z_\\odot$). We interpret these observations in light of new models of stellar evoluti...

  2. The Brightest Ly$\\alpha$ Emitter: Pop III or Black Hole?

    CERN Document Server

    Pallottini, A; Pacucci, F; Gallerani, S; Salvadori, S; Schneider, R; Schaerer, D; Sobral, D; Matthee, J

    2015-01-01

    CR7 is the brightest $z=6.6 \\, {\\rm Ly}\\alpha$ emitter (LAE) known to date, and spectroscopic follow-up by Sobral et al. (2015) suggests that CR7 might host Population (Pop) III stars. We examine this interpretation using cosmological hydrodynamical simulations. Several simulated galaxies show the same "Pop III wave" pattern observed in CR7. However, to reproduce the extreme CR7 ${\\rm Ly}\\alpha$/HeII1640 line luminosities ($L_{\\rm \\alpha/He II}$) a top-heavy IMF and a massive ($>10^{7}{\\rm M}_{\\odot}$) PopIII burst with age $10^{43.3}{\\rm erg}\\,{\\rm s}^{-1}$ should also host Pop III stars producing an observable $L_{\\rm He II}>10^{42.7}{\\rm erg}\\,{\\rm s}^{-1}$. As an alternate explanation, we explore the possibility that CR7 is instead powered by accretion onto a Direct Collapse Black Hole (DCBH). Our model predicts $L_{\\alpha}$, $L_{\\rm He II}$, and X-ray luminosities that are in agreement with the observations. In any case, the observed properties of CR7 indicate that this galaxy is most likely powered by s...

  3. METALLICITY EVOLUTION OF DAMPED Ly{alpha} SYSTEMS OUT TO z {approx} 5

    Energy Technology Data Exchange (ETDEWEB)

    Rafelski, Marc [Infrared Processing and Analysis Center, Caltech, Pasadena, CA 91125 (United States); Wolfe, Arthur M.; Neeleman, Marcel; Mendez, Alexander J. [Department of Physics and Center for Astrophysics and Space Sciences, UCSD, La Jolla, CA 92093 (United States); Prochaska, J. Xavier [Department of Astronomy and Astrophysics, UCO/Lick Observatory, 1156 High Street, University of California, Santa Cruz, CA 95064 (United States)

    2012-08-20

    We present chemical abundance measurements for 47 damped Ly{alpha} (DLA) systems, 30 at z > 4, observed with the Echellette Spectrograph and Imager and the High Resolution Echelle Spectrometer on the Keck telescopes. H I column densities of the DLAs are measured with Voigt profile fits to the Ly{alpha} profiles, and we find an increased number of false DLA identifications with Sloan Digital Sky Survey at z > 4 due to the increased density of the Ly{alpha} forest. Ionic column densities are determined using the apparent optical depth method, and we combine our new metallicity measurements with 195 from previous surveys to determine the evolution of the cosmic metallicity of neutral gas. We find the metallicity of DLAs decreases with increasing redshift, improving the significance of the trend and extending it to higher redshifts, with a linear fit of -0.22 {+-} 0.03 dex per unit redshift from z = 0.09-5.06. The metallicity 'floor' of Almost-Equal-To 1/600 solar continues out to z {approx} 5, despite our sensitivity for finding DLAs with much lower metallicities. However, this floor is not statistically different from a steep tail to the distribution. We also find that the intrinsic scatter of metallicity among DLAs of {approx}0.5 dex continues out to z {approx} 5. In addition, the metallicity distribution and the {alpha}/Fe ratios of z > 2 DLAs are consistent with being drawn from the same parent population with those of halo stars. It is therefore possible that the halo stars in the Milky Way formed out of gas that commonly exhibits DLA absorption at z > 2.

  4. The CALYMHA survey: Ly$\\alpha$ escape fraction and its dependence on galaxy properties at $z=2.23$

    CERN Document Server

    Matthee, Jorryt; Oteo, Ivàn; Best, Philip; Smail, Ian; Röttgering, Huub; Paulino-Afonso, Ana

    2016-01-01

    We present the first results from our CAlibrating LYMan-$\\alpha$ with H$\\alpha$ (CALYMHA) pilot survey at the Isaac Newton Telescope. We measure Ly$\\alpha$ emission for 488 H$\\alpha$ selected galaxies at $z=2.23$ from HiZELS in the COSMOS and UDS fields with a specially designed narrow-band filter ($\\lambda_c$ = 3918 {\\AA}, $\\Delta\\lambda$= 52 {\\AA}). We find 17 dual H$\\alpha$-Ly$\\alpha$ emitters ($f_{\\rm Ly\\alpha} >5\\times10^{-17}$ erg s$^{-1}$ cm$^{-2}$, of which 5 are X-ray AGN). For star-forming galaxies, we find a range of Ly$\\alpha$ escape fractions (f$_{\\rm esc}$, measured with 3$"$ apertures) from $2$\\%$-30$\\%. These galaxies have masses from $3\\times10^8$ M$_{\\odot}$ to 10$^{11}$ M$_{\\odot}$ and dust attenuations E$(B-V)=0-0.5$. Using stacking, we measure a median escape fraction of $1.6\\pm0.5$\\% ($4.0\\pm1.0$\\% without correcting H$\\alpha$ for dust), but show that this depends on galaxy properties. The stacked f$_{\\rm esc}$ tends to decrease with increasing SFR and dust attenuation. However, at the h...

  5. IUE high resolution spectrophotometry of H Ly alpha emission from the local interstellar medium

    Science.gov (United States)

    Clarke, J. T.; Bowyer, S.; Fahr, H. J.; Lay, G.

    1984-01-01

    IUE high dispersion spectra of resonantly scattered solar Ly alpha emission from H moving into the solar system with the local interstellar wind are reported which are based on observations conducted in April 1981 and April 1983. A heliocentric velocity of -29 + or - 5 km/s has been observed from the ISW component along with a surface brightness which has decreased from about 1000 to 800 Rayleighs over the two-year interval. A preliminary derivation of the velocity of the ISM at large distances from the sun yields a value of 25.6 + or - 5 km/s.

  6. Statistical characteristics of observed Ly-$\\alpha$ forest and the shape of linear power spectrum

    OpenAIRE

    Demianski, M.; Doroshkevich, A. G.; Turchaninov, V. I.

    2005-01-01

    Properties of $\\sim$ 6 000 Ly-$\\alpha$ absorbers observed in 19 high resolution spectra of QSOs are investigated using the model of formation and evolution of DM structure elements based on the Zel'dovich theory. This model asserts that absorbers are formed in the course of both linear and nonlinear adiabatic or shock compression of dark matter (DM) and gaseous matter. It allows us to link the column density and overdensity of DM and gaseous components with the observed column density of neut...

  7. The Hanle effect of Ly$\\alpha$ in an MHD model of the Solar Transition Region

    CERN Document Server

    Stepan, Jiri; Carlsson, Mats; Leenaarts, Jorrit

    2012-01-01

    In order to understand the heating of the solar corona it is crucial to obtain empirical information on the magnetic field in its lower boundary (the transition region). To this end, we need to measure and model the linear polarization produced by scattering processes in strong UV lines, such as the hydrogen Ly$\\alpha$ line. The interpretation of the observed Stokes profiles will require taking into account that the outer solar atmosphere is highly structured and dynamic, and that the height of the transition region may well vary from one place in the atmosphere to another. Here we report on the Ly$\\alpha$ scattering polarization signals we have calculated in a realistic model of an enhanced network region, resulting from a state-of-the-art radiation MHD simulation. This model is characterized by spatially complex variations of the physical quantities at transition region heights. The results of our investigation lead us to emphasize that scattering processes in the upper solar chromosphere should indeed prod...

  8. Effect of the intergalactic environment on the observability of Ly-alpha emitters during reionization

    CERN Document Server

    Iliev, Ilian T; McDonald, Patrick; Mellema, Garrelt; Pen, Ue-Li

    2007-01-01

    Observations of high-redshift Ly-alpha sources are a major tool for studying the high-redshift Universe. We discuss the effect of the reionizing intergalactic medium on the observability of Ly-alpha sources based on large simulations of early structure formation with radiative transfer. This takes into account self-consistently the reionization history, density, velocity and ionization structures and nonlinear source clustering. We find that all fields are highly anisotropic and as a consequence there are very large variations in opacity among the different lines-of-sight. The velocity effects, from both infall and source peculiar velocity are most important for the luminous sources, affecting the line profile and depressing the bright end of the luminosity function. The line profiles are generally asymmetric and the line centers of the luminous sources are always absorbed due to the high density of the local IGM. For both luminous and average sources the damping wing effects are of similar magnitude and rema...

  9. A ghostly damped Ly$\\alpha$ system revealed by metal absorption lines

    CERN Document Server

    Fathivavsari, Hassan; Zou, Siwei; Noterdaeme, Pasquier; Ledoux, Cédric; Krühler, Thomas; Srianand, Raghunathan

    2016-01-01

    We report the discovery of the first 'ghostly' damped Ly$\\alpha$ absorption system (DLA), which is identified by the presence of absorption from strong low-ion species at $z_{\\rm abs}=1.70465$ along the line of sight to the quasar SDSSJ113341.29$-$005740.0 with $z_{\\rm em}=1.70441$. No Ly$\\alpha$ absorption trough is seen associated with these absorptions because the DLA trough is filled with the leaked emission from the broad emission line region of the quasar. By modeling the quasar spectrum and analyzing the metal lines, we derive log$N$(HI)(cm$^{-2}$)$\\sim$21.0 $\\pm$ 0.3. The DLA cloud is small ($\\le$ 0.32 pc) thus not covering entirely the broad line region and is located at $\\ge$ 39 pc from the central active galactic nucleus (AGN). Although the DLA is slightly redshifted relative to the quasar, its metallicity ([S/H]=$-$0.41$\\pm$0.30) is intermediate between what is expected from infalling and outflowing gas. It could be possible that the DLA is part of some infalling material accreting onto the quasar...

  10. THE FAINT-END SLOPE OF THE REDSHIFT 5.7 Ly{alpha} LUMINOSITY FUNCTION

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Alaina L.; Martin, Crystal L. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Dressler, Alan; McCarthy, Patrick [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Sawicki, Marcin, E-mail: ahenry@physics.ucsb.edu [Department of Astronomy and Physics, Saint Mary' s University, Halifax, NS B3H 3C3 (Canada)

    2012-01-10

    Using new Keck DEIMOS spectroscopy, we examine the origin of the steep number counts of ultra-faint emission-line galaxies recently reported by Dressler et al. We confirm six Ly{alpha} emitters (LAEs), three of which have significant asymmetric line profiles with prominent wings extending 300-400 km s{sup -1} redward of the peak emission. With these six LAEs, we revise our previous estimate of the number of faint LAEs in the Dressler et al. survey. Combining these data with the density of bright LAEs in the Cosmic Evolution Survey and Subaru Deep Field provides the best constraints to date on the redshift 5.7 LAE luminosity function (LF). Schechter function parameters, {phi}* = 4.5 Multiplication-Sign 10{sup -4} Mpc{sup -3}, L* = 9.1 Multiplication-Sign 10{sup 42} erg s{sup -1}, and {alpha} = -1.70, are estimated using a maximum likelihood technique with a model for slit-losses. To place this result in the context of the UV-selected galaxy population, we investigate how various parameterizations of the Ly{alpha} equivalent width distribution, along with the measured UV-continuum LF, affect shape and normalization of the Ly{alpha} LF. The nominal model, which uses z {approx} 6 equivalent widths from the literature, falls short of the observed space density of LAEs at the bright end, possibly indicating a need for higher equivalent widths. This parameterization of the equivalent width distribution implies that as many as 50% of our faintest LAEs should have M{sub UV} > -18.0, rendering them undetectable in even the deepest Hubble Space Telescope surveys at this redshift. Hence, ultra-deep emission-line surveys find some of the faintest galaxies ever observed at the end of the reionization epoch. Such faint galaxies likely enrich the intergalactic medium with metals and maintain its ionized state in the post-reionization era. Observations of these objects provide a glimpse of the building blocks of present-day galaxies at an early time.

  11. A High Fraction of Ly-alpha-Emitters Among Galaxies with Extreme Emission Line Ratios at z ~ 2

    CERN Document Server

    Erb, Dawn K; Steidel, Charles C; Strom, Allison L; Rudie, Gwen C; Trainor, Ryan F; Shapley, Alice E; Reddy, Naveen A

    2016-01-01

    Star-forming galaxies form a sequence in the [OIII]/H-beta vs. [NII]/H-alpha diagnostic diagram, with low metallicity, highly ionized galaxies falling in the upper left corner. Drawing from a large sample of UV-selected star-forming galaxies at z~2 with rest-frame optical nebular emission line measurements from Keck-MOSFIRE, we select the extreme ~5% of the galaxies lying in this upper left corner, requiring log([NII]/H-alpha) = 0.75. These cuts identify galaxies with 12 + log(O/H) 20 A. We compare the equivalent width distribution of a sample of 522 UV-selected galaxies at 2.0Ly-alpha equivalent width -1 (-4) A, and only 9% of these galaxies qualify as LAEs. The extreme galaxies typically have lower attenuation at Ly-alpha than those in the comparison sample, and have ~50% lower median oxygen abundances. Both factors are likely to facilitate the escape of Ly-alpha: in less dusty galaxies Ly-alpha photons are l...

  12. The Evolution of Ly-alpha Emitting Galaxies Between z = 2.1 and z = 3.1

    OpenAIRE

    Ciardullo, Robin; Gronwall, Caryl; Wolf, Christopher; McCathran, Emily; Bond, Nicholas A.; Gawiser, Eric; Guaita, Lucia; Feldmeier, John J.; Treister, Ezequiel; Padilla, Nelson; Francke, Harold; Matkovic, Ana; Altmann, Martin; Herrera, David

    2011-01-01

    We describe the results of a new, wide-field survey for z=3.1 Ly-alpha emission-line galaxies (LAEs) in the Extended Chandra Deep Field South (ECDF-S). By using a nearly top-hat 5010 Angstrom filter and complementary broadband photometry from the MUSYC survey, we identify a complete sample of 141 objects with monochromatic fluxes brighter than 2.4E-17 ergs/cm^2/s and observers-frame equivalent widths greater than ~ 80 Angstroms (i.e., 20 Angstroms in the rest-frame of Ly-alpha). The bright-en...

  13. Photometric properties of Ly alpha emitters at z=4.86 in the COSMOS 2 square degree field

    CERN Document Server

    Shioya, Y; Sasaki, S S; Nagao, T; Murayama, T; Saitô, T; Ideue, Y; Nakajima, A; Matsuoka, K L; Trump, J; Scoville, N Z; Sanders, D B; Mobasher, B; Aussel, H; Capak, P; Kartaltepe, J; Koekemoer, A; Carilli, C; Ellis, Richard S; Garilli, B; Giavalisco, M; Kitzbichler, M G; Impey, C; LeFevre, O; Schinnerer, E; Smolcic, V

    2009-01-01

    We present results of a survey for Ly alpha emitters at z=4.86 based on optical narrowband (lambda_c=7126 angstrom, Delta lambda=73 angstrom) and broadband (B, V, r', i', and z') observations of the Cosmic Evolution Survey (COSMOS) field using Suprime-Cam on the Subaru Telescope. We find 79 LAE candidates at z=4.86 over a contiguous survey area of 1.83 deg^2, down to the Ly alpha line flux of 1.47 x 10^-17 ergs s^-1 cm^-2. We obtain the Ly alpha luminosity function with a best-fit Schechter parameters of log L^*=42.9^+0.5_-0.3 ergs s^-1 and phi^* = 1.2^+8.0_-1.1 x 10^-4 Mpc^-3 for alpha=-1.5 (fixed). The two-point correlation function for our LAE sample is xi(r) = (r/4.4^+5.7_-2.9 Mpc)^-1.90+/-0.22. In order to investigate the field-to-field variations of the properties of Ly alpha emitters, we divide the survey area into nine tiles of 0.5^circ x 0.5^circ each. We find that the number density varies with a factor of ~ 2 from field to field with high statistical significance. However, we find no significant fi...

  14. Statistical characteristics of observed Ly-$\\alpha$ forest and the shape of initial power spectrum

    CERN Document Server

    Demianski, M

    2002-01-01

    Properties of $\\sim$ 5000 observed Ly-$\\alpha$ absorbers are investigated using the model of formation and evolution of DM structure elements based on the Zel'dovich theory. This model is generally consistent with simulations of absorbers formation, accurately describes the Large Scale Structure observed in the galaxy distribution at small redshifts and emphasizes the generic similarity of the LSS and absorbers. The simple physical model of absorbers asserts that they are composed of DM and gaseous matter and it allows us to estimate the column density and overdensity of DM and gaseous components and the entropy of the gas trapped within the DM potential wells. The parameters of DM component are found to be consistent with theoretical expectations for the Gaussian initial perturbations with the WDM--like power spectrum. We demonstrate the influence of the main physical factors responsible for the absorbers evolution. The analysis of redshift distribution of absorbers confirms the self consistence of the assum...

  15. Synergy of CO/[CII]/Ly$\\alpha$ Line Intensity Mapping with the SKA

    CERN Document Server

    Chang, Tzu-Ching; Santos, Mario; Silva, Marta; Aguirre, James; Doré, Olivier; Pritchard, Jonathan

    2015-01-01

    We present the science enabled by cross-correlations of the SKA1-LOW 21-cm EoR surveys with other line mapping programs. In particular, we identify and investigate potential synergies with planned programs, such as the line intensity mapping of redshifted CO rotational lines, [CII] and Ly-$\\alpha$ emissions during reionization. We briefly describe how these tracers of the star-formation rate at $z \\sim 8$ can be modeled jointly before forecasting their auto- and cross-power spectra measurements with the nominal 21cm EoR survey. The use of multiple line tracers would be invaluable to validate and enrich our understanding of the EoR.

  16. Statistical characteristics of observed Ly-$\\alpha$ forest and the shape of linear power spectrum

    CERN Document Server

    Demianski, M

    2005-01-01

    Properties of $\\sim$ 6 000 Ly-$\\alpha$ absorbers observed in 19 high resolution spectra of QSOs are investigated using the model of formation and evolution of DM structure elements based on the Zel'dovich theory. This model asserts that absorbers are formed in the course of both linear and nonlinear adiabatic or shock compression of dark matter (DM) and gaseous matter. It allows us to link the column density and overdensity of DM and gaseous components with the observed column density of neutral hydrogen, redshifts and Doppler parameters of absorbers and demonstrates that at high redshifts we observe a self similar period of structure evolution with the Gaussian initial perturbations. We show that the colder absorbers are associated with rapidly expanded regions of a galactic scale which represent large amplitude negative density perturbations. We extend and improve the method of measuring the power spectrum of initial perturbations proposed in Demia\\'nski & Doroshkevich (2003b). Our method links the obse...

  17. Discovery of an Enormous Ly$\\alpha$ nebula in a massive galaxy overdensity at $z=2.3$

    CERN Document Server

    Cai, Zheng; Yang, Yujin; Bian, Fuyan; Prochaska, J Xavier; Zabludoff, Ann; McGreer, Ian; Zheng, Zhenya; Green, Richard; Cantalupo, Sebastiano; Frye, Brenda; Hamden, Erika; Jiang, Linhua; Kashikawa, Nobunari; Wang, Ran

    2016-01-01

    Enormous Ly$\\alpha$ Nebulae (ELANe), unique tracers of galaxy density peaks, are predicted to lie at the nodes and intersections of cosmic filamentary structures. Previous successful searches for ELANe have focused on wide-field narrowband surveys, or have targeted known sources such as ultraluminous quasi-stellar-objects (QSOs) or radio galaxies. Utilizing groups of coherently strong Ly$\\alpha$ absorptions (CoSLAs), we have developed a new method to identify high-redshift galaxy overdensities and have identified an extremely massive overdensity, BOSS1441, at $z=2-3$ (Cai et al. 2016a). In its density peak, we discover an ELAN that is associated with a relatively faint continuum. To date, this object has the highest diffuse Ly$\\alpha$ nebular luminosity of $L_{\\rm{nebula}}=5.1\\pm0.1\\times10^{44}$ erg s$^{-1}$. Above the 2$\\sigma$ surface brightness limit of SB$_{\\rm{Ly\\alpha}}= 4.8\\times10^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$, this nebula has an end-to-end spatial extent of 442 kpc. This radio-quiet so...

  18. WSRT detection of HI absorption in the z=3.4 damped Ly alpha system in PKS 0201+113

    NARCIS (Netherlands)

    deBruyn, AG; ODea, CP; Baum, SA

    1996-01-01

    We report the detection of a faint narrow HI absorption line at a redshift of 3.38 against the quasar PKS 0201+113 which itself has an emission redshift of 3.61. The absorption line redshift agrees, to within the errors, with that of a damped Ly alpha line. The line has a halfwidth of about 9 km s(-

  19. The Gravitational Lensing in the QSO 1208+10 from the Proximity Effect in its $Lyman \\alpha$ Forest

    CERN Document Server

    Giallongo, E; Cristiani, S; D'Odorico, S

    1999-01-01

    The quasar Q1208+1011 (z_{em}=3.8) is the second highest redshift double quasar ever detected. Several indications point toward it being a gravitational lensed system, although a definitive proof is still lacking. We present new evidence of its lensed nature based on the weakness of the ``proximity effect'' measured in the high resolution Lyman absorption spectrum of the QSO. A luminosity amplification as large as 22 has been derived from this analysis. Indications on the redshift of the lensing galaxy can be obtained from the analysis of the intervening heavy element absorption systems discovered in the QSO high resolution spectrum. On statistical and dynamical grounds a MgII system present at z=1.13 appears as the most likely candidate for the lensing galaxy. We compare the observed parameters with a simple isothermal model for the lens to derive the properties of the lensing galaxy. The resulting magnification factor is smaller, although marginally consistent with that derived by the analysis of the proxim...

  20. Variable Ly alpha sheds light on the environment surrounding GRB 090426

    CERN Document Server

    Thöne, C C; Lazzati, D; Postigo, A de Ugarte; Fynbo, J P U; Christensen, L; Levan, A J; Aloy, M A; Hjorth, J; Jakobsson, P; Levesque, E M; Malesani, D; Milvang-Jensen, B; Roming, P W A; Tanvir, N R; Wiersema, K; Gladders, M; Wuyts, E; Dahle, H

    2011-01-01

    Long duration gamma-ray bursts are commonly associated with the deaths of massive stars. Spectroscopic studies using the afterglow as a light source provide a unique opportunity to unveil the medium surrounding it, probing the densest region of their galaxies. This material is usually in a low ionisation state and at large distances from the burst site, hence representing the normal interstellar medium in the galaxy. Here we present the case of GRB 090426 at z=2.609, whose optical spectrum indicates an almost fully ionised medium together with a low column density of neutral hydrogen. For the first time, we also observe variations in the Ly alpha absorption line. Photoionisation modeling shows that we are probing material from the vicinity of the burst (~80 pc). The host galaxy is a complex of two luminous interacting galaxies, which might suggest that this burst could have occurred in an isolated star-forming region outside its host galaxy created in the interaction of the two galaxies.

  1. The Rapid Decline in Metallicity of Damped Ly-$\\alpha$ Systems at $z\\sim5$

    CERN Document Server

    Rafelski, Marc; Fumagalli, Michele; Wolfe, Arthur M; Prochaska, J Xavier

    2013-01-01

    We present evidence that the cosmological mean metallicity of neutral atomic hydrogen gas shows a sudden decrease at $z>4.7$ down to $=-2.03^{+0.09}_{-0.11}$, which is $6\\sigma$ deviant from that predicted by a linear fit to the data at lower redshifts. This measurement is made possible by the chemical abundance measurements of 8 new damped Ly-$\\alpha$ (DLA) systems at $z>4.7$ observed with the Echellette Spectrograph and Imager on the Keck II telescope, doubling the number of measurements at $z>4.7$ to 16. The sudden decrease in metallicity is possibly due to the lower ultra-violet radiation field and higher density at high redshift increasing the neutral fraction of gas inside halos, such as cold flows. This would result in a new population of presumably lower metallicity DLAs, with an increased contribution to the DLA population at higher redshifts resulting in a reduced mean metallicity. While the comoving metal mass density of DLAs, $\\rho_{\\rm metals}(z)_{\\rm DLA}$, is flat out to $z\\sim4.3$, there is ev...

  2. Baryon Acoustic Oscillations in the Ly{\\alpha} forest of BOSS DR11 quasars

    CERN Document Server

    Delubac, Timothée; Busca, Nicolás G; Rich, James; Kirkby, David; Bailey, Stephen; Font-Ribera, Andreu; Slosar, Anže; Lee, Khee-Gan; Pieri, Matthew M; Hamilton, Jean-Christophe; Aubourg, Éric; Blomqvist, Michael; Bovy, Jo; Brinkmann, J; Carithers, William; Dawson, Kyle S; Eisenstein, Daniel J; Kneib, Jean-Paul; Goff, J -M Le; Margala, Daniel; Miralda-Escudé, Jordi; Myers, Adam D; Nichol, Robert C; Noterdaeme, Pasquier; O'Connell, Ross; Olmstead, Matthew D; Palanque-Delabrouille, Nathalie; Pâris, Isabelle; Petitjean, Patrick; Ross, Nicholas P; Rossi, Graziano; Schlegel, David J; Schneider, Donald P; Weinberg, David H; Yèche, Christophe; York, Donald G

    2014-01-01

    We report a detection of the baryon acoustic oscillation (BAO) feature in the flux-correlation function of the Ly{\\alpha} forest of high-redshift quasars with a statistical significance of five standard deviations. The study uses 137,562 quasars in the redshift range $2.1\\le z \\le 3.5$ from the Data Release 11 (DR11) of the Baryon Oscillation Spectroscopic Survey (BOSS) of SDSS-III. This sample contains three times the number of quasars used in previous studies. The measured position of the BAO peak determines the angular distance, $D_A(z=2.34)$ and expansion rate, $H(z=2.34)$, both on a scale set by the sound horizon at the drag epoch, $r_d$. We find $D_A/r_d=11.28\\pm0.65(1\\sigma)^{+2.8}_{-1.2}(2\\sigma)$ and $D_H/r_d=9.18\\pm0.28(1\\sigma)\\pm0.6(2\\sigma)$ where $D_H=c/H$. The optimal combination, $\\sim D_H^{0.7}D_A^{0.3}/r_d$ is determined with a precision of $\\sim2\\%$. For the value $r_d=147.4~{\\rm Mpc}$, consistent with the CMB power spectrum measured by Planck, we find $D_A(z=2.34)=1662\\pm96(1\\sigma)~{\\rm M...

  3. Argon and Silicon abundances in the damped Ly-alpha system I Zw 18

    CERN Document Server

    Levshakov, S A; Agafonova, I I

    2000-01-01

    We show that the difference between the Ar and Si relative abundance ratio derived from FUSE absorption spectra and from the HII regions of I Zw 18 is a consequence of the microturbulent analysis applied to the absorption spectra. FUSE observations were performed with a large entrance aperture which fully covered the galaxy. This means that the observed profiles are averaged over the full body of I Zw 18, implying that large-scale velocity fields influence the absorption - line profiles. Taking this into account, we show that the absorption spectra are consistent with the same metal abundances as those derived from the HII regions. It follows that no significant ionization correction as suggested by Izotov and collaborators to describe metal contents in damped Ly-alpha systems (DLA) is required to model abundances in the neutral gas of I Zw 18 (a local DLA system). Using a mesoturbulent approach and applying the generalized radiative transfer equation to the ArI1048 and SiII1020 lines observed by Vidal-Madjar...

  4. The Nature of the Low-redshift Ly-$\\alpha$ Clouds

    CERN Document Server

    Shull, J M

    1997-01-01

    I discuss recent HST observations and interpretation of low-z Ly-alpha clouds toward nearby Seyferts and QSOs, including their frequency, space density, estimated mass, association with galaxies, and contribution to Omega_b. Our HST/GHRS detections of 73 Lya absorbers with N_HI > 10^12.6 cm^(-2) along 11 sightlines covering pathlength Delta(cz) = 86,000 km/s show f(>N_HI) proportional to N_HI^(-0.6 +/- 0.2). A group of strong absorbers toward PKS~2155-304 may be associated with gas (400-800)/h_75 kpc from 4 large galaxies with low metallicity (<0.004 solar) and D/H < 2 x 10^-4. At low-z, we derive a metagalactic ionizing radiation field and Lya-forest baryon density J_0 = (1.1 +/- 0.4) x 10^(-23) ergs/cm^2/s/Hz/sr and Omega_b = (0.008 +/- 0.004) h_75^(-1) [J_-23 N_14 b_100]^0.5 for clouds of characteristic size b = (100 kpc)b_100.

  5. Ly Alpha-Emitting Galaxies at z=3.1: L* Progenitors Experiencing Rapid Star Formation

    CERN Document Server

    Gawiser, Eric; Lai, Kamson; Schawinski, Kevin; Gronwall, Caryl; Ciardullo, Robin; Quadri, Ryan; Orsi, Alvaro; Barrientos, L Felipe; Blanc, Guillermo A; Fazio, Giovanni; Feldmeier, John J; Huang, Jia-Sheng; Infante, Leopoldo; Lira, Paulina; Padilla, Nelson; Taylor, Edward N; Treister, Ezequiel; Urry, C Megan; van Dokkum, Pieter G; Virani, Shanil N

    2007-01-01

    We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample of 162 Ly Alpha-Emitting (LAE) galaxies at z=3.1 discovered in deep narrow-band MUSYC imaging of the Extended Chandra Deep Field South. LAEs were selected to have observed frame equivalent widths >80A and emission line fluxes >1.5E-17 erg/cm^2/s. Only 1% of our LAE sample appears to host AGN. The LAEs exhibit a moderate spatial correlation length of r_0=3.6+0.8-1.0 Mpc, corresponding to a bias factor b=1.7+0.3-0.4, which implies median dark matter halo masses of log10(M_med) = 10.9+0.5-0.9 M_sun. Comparing the number density of LAEs, (1.5+-0.3)E-3/Mpc^3, with the number density of these halos finds a mean halo occupation ~1-10%. The evolution of galaxy bias with redshift implies that most z=3.1 LAEs evolve into present-day galaxies with L3 galaxy populations typically evolve into more massive galaxies. Halo merger trees show that z=0 descendants occupy halos with a wide range of masses, with a median de...

  6. Copernicus observations of Ly-alpha and Mg II emission from HR 1099 /V711 Tauri/ and UX Ari

    Science.gov (United States)

    Weiler, E. J.

    1978-01-01

    Ultraviolet observations of two RS CVn binaries obtained with Copernicus are described. High-resolution (0.05 A) U1 observations indicate that both HR 1099 and UX Ari display broad Ly-alpha emission. The Ly-alpha emission strength from HR 1099 is variable and seems to be correlated with orbital phase, while the UX Ari results indicate no significant variation. Moderate resolution (0.51 A) V2 scans of both systems show variable Mg II h and k emission-line profiles which usually matched the velocity of the more active star in each binary. Additionally, displaced emission components were seen at velocities of up to + or - 250 km/s, indicative of high-velocity gas motions. The radial velocities of these emission features from HR 1099 are marginally correlated with orbital phase. Highly active and variable chromospheric phenomena are found to be the most consistent explanation of these results.

  7. Copernicus observations of Ly-alpha and Mg II emission from HR 1099 /V711 Tauri/ and UX Ari

    Science.gov (United States)

    Weiler, E. J.

    1978-01-01

    Ultraviolet observations of two RS CVn binaries obtained with Copernicus are described. High-resolution (0.05 A) U1 observations indicate that both HR 1099 and UX Ari display broad Ly-alpha emission. The Ly-alpha emission strength from HR 1099 is variable and seems to be correlated with orbital phase, while the UX Ari results indicate no significant variation. Moderate resolution (0.51 A) V2 scans of both systems show variable Mg II h and k emission-line profiles which usually matched the velocity of the more active star in each binary. Additionally, displaced emission components were seen at velocities of up to + or - 250 km/s, indicative of high-velocity gas motions. The radial velocities of these emission features from HR 1099 are marginally correlated with orbital phase. Highly active and variable chromospheric phenomena are found to be the most consistent explanation of these results.

  8. The Properties of Ly-Alpha Absorbers at Redshifts Between 0.9z<1.5

    Science.gov (United States)

    Jannuzi, Buell

    2000-07-01

    We propose to use STIS to obtain new Echelle resolution {10 km/ sec} spectra of three bright quasars which, when combined with archived and scheduled observations, will be used to characterize the properties of Ly-Alpha absorbers in the redshift range 0.9zz 1 {e.g., Zhang et al. 1997; Dave et al. 1998; Riediger et al. 1998; and Theuns et al. 1998}. While the simulations have all managed to reproduce the general observed properties of z 3 absorbers, they make different predictions for these properties at z 1. These differences arise because the expansion history of the universe and the rate of structure formation depend on the values of Omega and Lambda, and both affect the evolution of statistical properties of the absorbers. More broadly, comparison between the properties at z 1 and those at higher redshifts can test whether structure in the Ly-Alpha forest is evolving in the manner predicted by gravitational instability theories.

  9. Ionization and feedback in Ly$\\alpha$ halos around two radio galaxies at z$\\sim$2.5

    CERN Document Server

    Morais, S G; Villar-Martín, M; Lagos, P; Moyano, M; Overzier, R; Alighieri, S di Serego; Vernet, J; Fernandes, C A C

    2016-01-01

    We present new spectroscopic observations of two high redshift radio galaxies, TXS 0211-122 (z=2.34) and TXS 0828+193 (z=2.57), known to be associated with large Ly$\\alpha$ halos. The observations were taken with the slits placed perpendicularly to the radio axis. With access to pre-existing Keck II observations taken with the slit placed along the radio axis we are able to compare the properties of the gas in different regions of the galaxies. In both objects we detect spatially extended Ly$\\alpha$ emission perpendicularly to the radio axis. In TXS 0211-122, the flux and velocity profiles of Ly$\\alpha$ are strongly affected by HI absorption/scattering. In line with previous studies, we find evidence for outflowing gas along the radio axis which may be the result of jet-gas interactions. In the slit oriented perpendicularly to the radio axis we find less perturbed gas kinematics, suggesting outflows of ionized gas in this object are focused along the radio jet axis. Additionally, we find evidence for a giant,...

  10. Spectral Energy Distribution Fitting of Hetdex Pilot Survey Ly-alpha Emitters in Cosmos and Goods-N

    Science.gov (United States)

    Hagen, Alex; Ciardullo, Robin; Cronwall, Caryl; Acquaviva, Viviana; Bridge, Joanna; Zeimann, Gregory R.; Blanc, Guillermo; Bond, Nicholas; Finkelstein, Steven L.; Song, Mimi; Gawiser, Eric; Fox, Derek B.; Gebhardt, Henry; Malz, A. I; Schneider, Donald P.; Drory, Niv; Gebhardt, Karl; Hill, Gary J.

    2014-01-01

    We use broadband photometry extending from the rest-frame UV to the near-IR to fit the individual spectral energy distributions of 63 bright (L(Ly-alpha) greater than 10(exp 43) erg s(exp -1) Ly-alpha emitting galaxies (LAEs) in the redshift range 1.9 less than z less than 3.6. We find that these LAEs are quite heterogeneous, with stellar masses that span over three orders of magnitude, from 7.5 greater than logM/solar mass less than 10.5. Moreover, although most LAEs have small amounts of extinction, some high-mass objects have stellar reddenings as large as E(B - V ) is approximately 0.4. Interestingly, in dusty objects the optical depths for Ly-alpha and the UV continuum are always similar, indicating that Lya photons are not undergoing many scatters before escaping their galaxy. In contrast, the ratio of optical depths in low-reddening systems can vary widely, illustrating the diverse nature of the systems. Finally, we show that in the star-formation-rate-log-mass diagram, our LAEs fall above the "main-sequence" defined by z is approximately 3 continuum selected star-forming galaxies. In this respect, they are similar to submillimeter-selected galaxies, although most LAEs have much lower mass.

  11. FIRST SPECTROSCOPIC EVIDENCE FOR HIGH IONIZATION STATE AND LOW OXYGEN ABUNDANCE IN Ly{alpha} EMITTERS ,

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kimihiko; Shimasaku, Kazuhiro; Hashimoto, Takuya; Ono, Yoshiaki [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ouchi, Masami [Kavli Institute for the Physics and Mathematics of the Universe (WPI), University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Lee, Janice C., E-mail: nakajima@astron.s.u-tokyo.ac.jp [Space Telescope Science Institute, Baltimore, MD 21218 (United States)

    2013-05-20

    We present results from Keck/NIRSPEC and Magellan/MMIRS follow-up spectroscopy of Ly{alpha} emitters (LAEs) at z = 2.2 identified in our Subaru narrowband survey. We successfully detect H{alpha} emission from seven LAEs, and perform a detailed analysis of six LAEs free from active galactic nucleus activity, two out of which, CDFS-3865 and COSMOS-30679, have [O II] and [O III] line detections. They are the first [O II]-detected LAEs at high-z, and their [O III]/[O II] ratios and R23-indices provide the first simultaneous determinations of ionization parameter and oxygen abundance for LAEs. CDFS-3865 has a very high ionization parameter (q{sub ion}=2.5{sup +1.7}{sub -0.8} Multiplication-Sign 10{sup 8} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=7.84{sup +0.24}{sub -0.25}) in contrast with moderate values of other high-z galaxies such as Lyman break galaxies (LBGs). COSMOS-30679 also possesses a relatively high ionization parameter (q{sub ion}=8{sup +10}{sub -4} Multiplication-Sign 10{sup 7} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=8.18{sup +0.28}{sub -0.28}). Both LAEs appear to fall below the mass-metallicity relation of z {approx} 2 LBGs. Similarly, a low metallicity of 12 + log (O/H) < 8.4 is independently indicated for typical LAEs from a composite spectrum and the [N II]/H{alpha} index. Such high ionization parameters and low oxygen abundances can be found in local star-forming galaxies, but this extreme local population occupies only {approx}0.06% of the Sloan Digital Sky Survey spectroscopic galaxy sample with a number density {approx}100 times smaller than that of LAEs. With their high ionization parameters and low oxygen abundances, LAEs would represent an early stage of galaxy formation dominated by massive stars in compact star-forming regions. High-q{sub ion} galaxies like LAEs would produce ionizing photons efficiently with a high escape fraction achieved by density-bounded H II regions, which would significantly contribute to

  12. Large scale environmental bias of the QSO line of sight proximity effect

    CERN Document Server

    Partl, Adrian M; Yepes, Gustavo; Gottlöber, Stefan

    2011-01-01

    We analyse the proximity zone of the intergalactic matter around high-redshift quasars in a cosmological environment. In a box of 64 h-1 Mpc base length we employ dark matter only simulations. For estimating the hydrogen temperature and density distribution we use the effective equation of state. Hydrogen is assumed to be in photoionisation equilibrium with a model background flux which is fit to recent observations of the mean optical depth and transmission flux statistics. At redshifts z = 3, 4, and 4.8, we select model quasar positions at the centre of the 20 most massive halos and 100 less massive halos identified in the simulation. From each assumed quasar position we cast 100 random lines of sight for two box length including the changes in the ionisation fractions by the QSO flux field and derive mock Ly{\\alpha} spectra. The proximity effect describes the dependence of the mean normalised optical depth {\\xi} = {\\tau}eff, QSO/{\\tau}eff, Ly{\\alpha} as a function of the ratio of the ionisation rate by the...

  13. Metallicities, dust and molecular content of a QSO-Damped Lyman-{\\alpha} system reaching log N (H i) = 22: An analog to GRB-DLAs

    CERN Document Server

    Guimarães, R; Petitjean, P; Ledoux, C; Srianand, R; Lopez, S; Rahmani, H

    2012-01-01

    We present the elemental abundance and H2 content measurements of a Damped Lyman-{\\alpha} (DLA) system with an extremely large H i column density, log N(H i) (cm-2) = 22.0+/-0.10, at zabs = 3.287 towards the QSO SDSS J 081634+144612. We measure column densities of H2, C i, C i^*, Zn ii, Fe ii, Cr ii, Ni ii and Si ii from a high signal-to-noise and high spectral resolution VLT-UVES spectrum. The overall metallicity of the system is [Zn/H] = -1.10 +/- 0.10 relative to solar. Two molecular hydrogen absorption components are seen at z = 3.28667 and 3.28742 (a velocity separation of \\approx 52 km s-1) in rotational levels up to J = 3. We derive a total H2 column density of log N(H2) (cm-2) = 18.66 and a mean molecular fraction of f = 2N(H2)/[2N(H2) + N(H i)] = 10-3.04+/-0.37, typical of known H2-bearing DLA systems. From the observed abundance ratios we conclude that dust is present in the Interstellar Medium (ISM) of this galaxy, with a enhanced abundance in the H2-bearing clouds. However, the total amount of dus...

  14. The luminosity function of Ly-alpha emitters at 2.3 < z < 4.6 from integral-field spectroscopy

    CERN Document Server

    Van Breukelen, C; Venemans, B P; Breukelen, Caroline van; Jarvis, Matt J.; Venemans, Bram P.

    2005-01-01

    We have used VIsible MultiObject Spectrograph Integral-Field Unit (VIMOS-IFU) observations centred on a radio galaxy at z=2.9 to search for Ly-alpha emitters within a comoving volume of ~ 10^4 Mpc^3. We find 14 Ly-alpha emitters with flux > 1.4 x 10^-20 Wm^-2, yielding a comoving space density of 0.0018 +/- 0.0006 Mpc^-3. We fit a Schechter luminosity function which agrees well with previous studies both at similar redshift (z ~ 3.4) and higher redshift (z ~ 5.7). We therefore find no evidence for evolution in the properties of Ly-alpha emitters between 3 < z < 6, although our sample is small. By summing the star-formation rates of the individual Ly-alpha emitters we find a total cosmic star-formation rate density of rho_SFR = 6.7 +/- 0.5 x 10^-3 M_solar yr^-1 Mpc^-3. Integrating over the luminosity function for the combined Ly-alpha surveys at z ~ 3.4 and accounting for the difference in obscuration between the Ly-alpha line and the UV-continuum yields an estimate of rho_SFR ~ 2.2 x 10^-2 M_solar yr^-1...

  15. A giant Ly$\\alpha$ nebula in the core of an X-ray cluster at $z=1.99$: implications for early energy injection

    CERN Document Server

    Valentino, F; Finoguenov, A; Strazzullo, V; Brun, A M C Le; Vignali, C; Bournaud, F; Dickinson, M; Renzini, A; Béthermin, M; Zanella, A; Gobat, R; Cimatti, A; Elbaz, D; Onodera, M; Pannella, M; Sargent, M T; Arimoto, N; Carollo, M; Starck, J-L

    2016-01-01

    We present the discovery of a giant $\\gtrsim$100 kpc Ly$\\alpha$ nebula detected in the core of the X-ray emitting cluster CL J1449+0856 at $z=1.99$ through Keck/LRIS narrow-band imaging. This detection extends the known relation between Ly$\\alpha$ nebulae and overdense regions of the Universe to the dense core of a $5-7\\times10^{13}$ M$_{\\odot}$ cluster. The most plausible candidates to power the nebula are two Chandra-detected AGN host cluster members. Given the physical conditions of the Ly$\\alpha$-emitting gas and the possible interplay with the X-ray phase, we argue that the Ly$\\alpha$ nebula would be short-lived ($\\lesssim10$ Myr) if not continuously replenished with cold gas at a rate of $\\gtrsim1000$ Myr. Cooling from the X-ray phase is disfavored as the replenishing mechanism, primarily because of the high Ly$\\alpha$ to X-ray luminosity ratio ($L_{\\mathrm{Ly\\alpha}}/L_{\\mathrm{X}} \\approx0.3$), $\\gtrsim10-1000\\times$ higher than in local cool-core clusters. Cosmological cold flows are disfavored by cu...

  16. Spectro-polarimetry confirms central powering of a Ly$\\alpha$ nebula at z=3.09

    CERN Document Server

    Beck, Melanie; Hayes, Matthew; Dijkstra, Mark; Jones, Terry J

    2016-01-01

    We present a follow-up study to the imaging polarimetry performed by Hayes et. al. 2011 on LAB1 in the SSA22 protocluster region. Arguably the most well-known Lyman-$\\alpha$ "blob", this radio-quiet emission-line nebula likely hosts a galaxy which is either undergoing significant star formation or hosts an AGN, or both. We obtain deep, spatially resolved spectro-polarimetry of the Ly$\\alpha$ emission and detect integrated linear polarization of $9$-$13\\%\\pm2$-$3\\%$ at a distance of approximately 15 kpc north and south of the peak of the Lyman-$\\alpha$ surface brightness with polarization vectors lying tangential to the galactic central source. In these same regions, we also detect a wavelength dependence in the polarization which is low at the center of the Ly$\\alpha$ line profile and rises substantially in the wings of the profile. These polarization signatures are easily explained by a weak out-flowing shell model. The spectral dependence of the polarization presented here provide a framework for future obs...

  17. Probing the Circumgalactic Medium of Submillimeter Galaxies with QSO Absorption Line Spectroscopy

    Science.gov (United States)

    Fu, Hai; Hennawi, Joseph F.; Prochaska, Jason X.; Stockton, Alan N.; Mutel, Robert Lucien; Casey, Caitlin; Cooray, Asantha R.; Keres, Dusan

    2017-01-01

    We present first results from an ongoing survey to characterize the circumgalactic medium (CGM) of the massive high-redshift galaxieds detected as submillimeter galaxies (SMGs). By cross-matching far-infrared-selected galaxies from Herschel with spectroscopically confirmed quasars, we constructed a sample of 163 SMG-QSO pairs with separations less than 36". We observed 62 SMG-QSO pairs with the Very Large Array (VLA) and the Atacama Large Millimeter Array (ALMA). These observations obtained sub-arcsecond positions of 31 SMGs and identified seven previously-thought SMG-QSO pairs as submillimeter-luminous QSOs. We are currently conducting a redshift survey of the VLA/ALMA-confirmed SMGs and acquiring high S/N UV-optical specrtoscopy of the background QSOs. For the small sample of three VLA-confirmed SMG-QSO pairs that we have the complete data set, absorption line spectra of the background QSOs allow us to analyze the CGM of SMGs for the first time, providing insight into the fuel-supply ultimately powering their tremendous starbursts. Our observations reveal strong HI Ly-alpha absorption (rest-frame equivalent widths about 2-3 A) around all three SMGs; however, none exhibit compelling evidence for strong neutral absorbers (NHI > 1017.2 cm-2) or metal absorption, allowing us to place an 1-sigma upper limit on the covering factor of optically thick HI gas around SMGs of fC cool gas reservoirs in their halos and that they may inhabit much less massive halos than previously thought.

  18. The Grism Lens-Amplified Survey from Space (GLASS). III. A census of Ly\\alpha\\ Emission at $z\\gtrsim$7 from HST Spectroscopy

    CERN Document Server

    Schmidt, K B; Bradač, M; Vulcani, B; Huang, K -H; Hoag, A; Maseda, M; Guaita, L; Pentericci, L; Brammer, G B; Dijkstra, M; Dressler, A; Fontana, A; Henry, A L; Jones, T A; Mason, C; Trenti, M; Wang, X

    2015-01-01

    [abbreviated] We present a census of Ly\\alpha\\ emission at $z\\gtrsim7$ utilizing deep near infrared HST grism spectroscopy from the first six completed clusters of the Grism Lens-Amplified Survey from Space (GLASS). In 24/159 photometrically selected galaxies we detect emission lines consistent with Ly\\alpha\\ in the GLASS spectra. Based on the distribution of signal-to-noise ratios and on simulations we expect the completeness and the purity of the sample to be 40-100% and 60-90%, respectively. For the objects without detected emission lines we show that the observed (not corrected for lensing magnification) 1$\\sigma$ flux limits reaches $5\\times10^{-18}$erg/s/cm$^{2}$ per position angle over the full wavelength range of GLASS (0.8-1.7$\\mu$m). Based on the conditional probability of Ly\\alpha\\ emission measured from the ground at $z\\sim7$ we would have expected 12-18 Ly\\alpha\\ emitters. This is consistent with the number of detections, within the uncertainties, confirming the drop in Ly\\alpha\\ emission with re...

  19. The BOSS Emission-Line Lens Survey. III. : Strong Lensing of Ly$\\alpha$ Emitters by Individual Galaxies

    CERN Document Server

    Shu, Yiping; Kochanek, Christopher S; Oguri, Masamune; Perez-Fournon, Ismael; Zheng, Zheng; Mao, Shude; Montero-Dorta, Antonio D; Brownstein, Joel R; Marques-Chaves, Rui; Menard, Brice

    2016-01-01

    We introduce the BOSS Emission-Line Lens Survey (BELLS) GALaxy-Ly$\\alpha$ EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Ly$\\alpha$ emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BOSS Emission-Line Lens Survey, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy-LAE candidates selected from $\\approx 1.4 \\times 10^6$ galaxy spectra in the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital...

  20. Chemical Evolution of Damped Ly $\\alpha$ galaxies The [S/Zn] abundance ratio at redshift z > 2

    CERN Document Server

    Centurion, M; Molaro, P; Vladilo, G; Centurion, Miriam; Bonifacio, Piercarlo; Molaro, Paolo; Vladilo, Giovanni

    2000-01-01

    Relative elemental abundances, and in particular the alpha/Fe ratio, are an important diagnostic tool of the chemical evolution of damped Ly alpha systems (DLAs). The S/Zn ratio is not affected by differential dust depletion and is an excellent estimator of the alpha/Fe ratio. We report 6 new determinations of sulphur abundance in DLAs at zabs greater than or equal to 2 with already known zinc abundances. The combination with extant data from the literature provides a measure of the S/Zn abundance ratio for a total of 11 high redshift DLA systems. The observed [S/Zn] ratios do not show the characteristic [alpha/Fe] enhancement observed in metal-poor stars of the Milky Way at comparable level of metallicity ([Zn/H] ~ -1). The behaviour of DLAs data is consistent with a general trend of decreasing [S/Zn] ratio with increasing metallicity [Zn/H]. This would be the first evidence of the expected decrease of the alpha/Fe ratio in the course of chemical evolution of DLA systems. However, in contrast to what observe...

  1. A Method to Measure the Mass of Damped Ly-alpha Absorber Host Galaxies Using Fluctuations in 21cm Emission

    CERN Document Server

    Wyithe, Stuart

    2008-01-01

    Observations of damped Ly-alpha absorbers (DLA) indicate that the fraction of hydrogen in its neutral form (HI) is significant by mass at all redshifts. This gas represents the reservoir of material that is available for star formation at late times. As a result, observational identification of the systems in which this neutral hydrogen resides is an important missing ingredient in models of galaxy formation. Precise identification of DLA host mass via traditional clustering studies is not practical owing to the small numbers of known systems being spread across sparsely distributed sight lines. However following the completion of reionization, 21cm surface brightness fluctuations will be dominated by neutral hydrogen in DLAs. Observations of these fluctuations will measure the combined clustering signal from all DLAs within a large volume. We show that measurement of the spherically averaged power-spectrum of 21cm intensity fluctuations due to DLAs could be used to measure the galaxy bias for DLA host galaxi...

  2. Directly imaging damped Ly-alpha galaxies at z>2. II: Imaging and spectroscopic observations of 32 quasar fields

    CERN Document Server

    Fumagalli, Michele; Prochaska, J Xavier; Kanekar, Nissim; Wolfe, Arthur M

    2014-01-01

    Damped Ly-alpha absorbers (DLAs) are a well-studied class of absorption line systems, and yet the properties of their host galaxies remain largely unknown. To investigate the origin of these systems, we have conducted an imaging survey of 32 quasar fields with intervening DLAs between z~1.9-3.8, leveraging a technique that allows us to image galaxies at any small angular separation from the background quasars. In this paper, we present the properties of the targeted DLA sample, new imaging observations of the quasar fields, and the analysis of new and archival spectra of the background quasars. In a companion paper we use these data to obtain an unbiased census of the DLA host galaxy population(s) and to directly measure the in-situ star formation rates of gas-rich galaxies at z>2.

  3. Modeling the Scattering Polarization of the Hydrogen Ly-alpha Line Observed by CLASP in a Filament Channel

    Science.gov (United States)

    Stepan, J.; Trujillo Bueno, J.; Gunar, S.; del Pino Aleman, T.; Heinzel, P.; Kano, R.; Ishikawa, R.; Narukage, M.; Bando, T.; Winebarger, Amy; Kobayashi, K.; Auchere, F.

    2016-01-01

    The 400 arcsec spectrograph slit of CLASP crossed predominantly quiet regions of the solar chromosphere, from the limb towards the solar disk center. Interestingly, in the CLASP slit-jaw images and in the SDO images of the He I line at 304 A, we can identify a filament channel (FC) extending over more than 60 arcsec crossing the spectrograph slit. In order to interpret the peculiar spatial variation of the Q/1 and U/1 signals observed by CLASP in the hydrogen Ly-alpha line (1216 A) and in the Si Ill line (1206 A) in such a filament channel, it is necessary to perform multi-dimensional radiative transfer modeling. In this contribution, we show the first results of the two-dimensional calculations we are carrying out in given filament models, with the aim of determining the filament thermal and magnetic structure by comparing the theoretical and the observed polarization signals.

  4. A Pair of O VI and Broad Ly-alpha Absorbers Probing Warm Gas in a Galaxy Group Environment at z ~ 0.4

    CERN Document Server

    Pachat, Sachin; Muzahid, Sowgat; Khaire, Vikram; Srianand, Raghunathan; Wakker, Bart P; Savage, Blair D

    2016-01-01

    We report on the detection of two O VI absorbers separated in velocity by 710 km/s at z ~ 0.4 towards the background quasar SBS0957+599. Both absorbers are multiphase systems tracing substantial reservoirs of warm baryons. The low and intermediate ionization metals in the first absorber is consistent with an origin in photoionized gas. The O VI has a velocity structure different from other metal species. The Ly-alpha shows the presence of a broad feature. The line widths for O VI and the broad Ly-alpha suggest T = 7.1 x 10^5 K. This warm medium is probing a baryonic column which is an order of magnitude more than the total hydrogen in the cooler photoionized gas. The second absorber is detected only in H I and O VI. Here the temperature of 4.6 x 10^4 K supports O VI originating in a low-density photoionized gas. A broad component is seen in the Ly-alpha, offset from the O VI. The temperature in the broad Ly-alpha is T < 2.1 x 10^5 K. The absorbers reside in a galaxy overdensity region with 7 spectroscopica...

  5. Discovery of an Overdensity of Lyman-alpha Emitters Around a $\\mathrm{z}\\sim4$ QSO with the Large Binocular Telescope

    CERN Document Server

    Adams, Scott M; Croxall, Kevin V; Overzier, Roderik A; Silverman, John D

    2014-01-01

    Measurements of QSO clustering in the SDSS show that $\\mathrm{z}>4$ QSOs are some of the most highly biased objects in the universe. Their large correlation lengths of $r_0 \\sim 20h^{-1}$Mpc are comparable to the most massive clusters of galaxies in the universe today and suggest that these QSOs may mark the locations of massive cluster progenitors at high redshift. We report the discovery of an overdensity of LBGs around QSO SDSSJ114514.18+394715.9 as part of our survey to identify Lyman-Break galaxies (LBGs) around luminous $\\mathrm{z}\\sim4$ QSOs. In this field three of the eight LBGs with secure redshifts are consistent with the redshift of the QSO. We find that the likelihood that this is merely an apparent overdensity due to the chance selection of field galaxies is only 0.02%, based on comparisons to simulations and our modeled selection efficiency. Overall, our survey finds four of the 15 LBGs with secure redshifts are consistent with the redshifts of their respective QSOs, which is consistent with lum...

  6. Low redshift Lyman alpha absorption lines and the dark matter halos of disk galaxies

    Science.gov (United States)

    Maloney, Philip

    1993-01-01

    Recent observations using the Hubble Space Telescope of the z = 0.156 QSO 3C 273 have discovered a surprisingly large number of Ly-alpha absorption lines. In particular, Morris et al. found 9 certain and 7 possible Ly-alpha lines with equivalent widths above 25 mA. This is much larger (by a factor of 5-10) than the number expected from extrapolation of the high-redshift behavior of the Ly-alpha forest. Within the context of pressure-confined models for the Ly-alpha clouds, this behavior can be understood if the ionizing background declines sharply between z is approximately 2 and z is approximately 0. However, this requires that the ionizing photon flux drop as rapidly as the QSO volume emissivity; moreover, the absorbers must have a space density n(sub O) is approximately 2.6(N/10)h/((D/100 kpc)(sup 2)) Mpc(sup -3) where D is the present-day diameter of the absorbers. It is somewhat surprising that such necessarily fragile objects could have survived in such numbers to the present day. It is shown that it is plausible that the atomic hydrogen extents of spiral and irregular galaxies are large enough to produce the observed number of Ly-alpha absorption lines toward 3C 273, and that the neutral column densities and doppler b-values expected under these conditions fall in the range found by Morris et al. (1991).

  7. A Luminosity Function of Ly(alpha)-Emitting Galaxies at Z [Approx. Equal to] 4.5(Sup 1),(Sup 2)

    Science.gov (United States)

    Dawson, Steve; Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel; Wang, JunXian; Dey, Arjun; Spinrad, Hyron; Jannuzi, Buell T.

    2007-01-01

    We present a catalog of 59 z [approx. equal to] 4:5 Ly(alpha)-emitting galaxies spectroscopically confirmed in a campaign of Keck DEIMOS follow-up observations to candidates selected in the Large Are (LALA) narrowband imaging survey.We targeted 97 candidates for spectroscopic follow-up; by accounting for the variety of conditions under which we performed spectroscopy, we estimate a selection reliability of approx.76%. Together with our previous sample of Keck LRIS confirmations, the 59 sources confirmed herein bring the total catalog to 73 spectroscopically confirmed z [approx. equal to] 4:5 Ly(alpha)- emitting galaxies in the [approx. equal to] 0.7 deg(exp 2) covered by the LALA imaging. As with the Keck LRIS sample, we find that a nonnegligible fraction of the co rest-frame equivalent widths (W(sub lambda)(sup rest)) that exceed the maximum predicted for normal stellar populations: 17%-31%(93%confidence) of the detected galaxies show (W(sub lambda)(sup rest)) 12%-27% (90% confidence) show (W(sub lambda)(sup rest)) > 240 A. We construct a luminosity function of z [approx. equal to] 4.5 Ly(alpha) emission lines for comparison to Ly(alpha) luminosity function < 6.6. We find no significant evidence for Ly(alpha) luminosity function evolution from z [approx. equal to] 3 to z [approx. equal to] 6. This result supports the conclusion that the intergalactic me largely reionized from the local universe out to z [approx. equal to] 6.5. It is somewhat at odds with the pronounced drop in the cosmic star formation rate density recently measured between z approx. 3 an z approx. 6 in continuum-selected Lyman-break galaxies, and therefore potentially sheds light on the relationship between the two populations.

  8. MgII Absorption Lines in z=2.974 Damped Lyman-alpha System toward Gravitationally Lensed QSO APM 08279+5255 Detection of Small-scale Structure in MgII Absorbing Clouds

    CERN Document Server

    Kobayashi, N; Goto, M; Tokunaga, A; Kobayashi, Naoto; Terada, Hiroshi; Goto, Miwa; Tokunaga, Alan

    2002-01-01

    1.02-1.16 micron spectra (R ~ 7,000) of the gravitationally lensed QSO APM 08279+5255 at z_em=3.911 were obtained during the commissioning run of IRCS, the 1-5 micron near-infrared camera and spectrograph for the Subaru 8.2 m Telescope. Strong MgII doublet at 2976,2800 angstrom and FeII (2600 angstrom), FeII (2587 angstrom) absorption lines at z_abs=2.974 were clearly detected in the rest-frame UV spectra, confirming the presence of a damped Lyman-alpha system at the redshift as suggested by Petitjean et al. Also MgI (2853 angstrom) absorption line is probably detected. An analysis of the absorption lines including velocity decomposition was performed. This is a first detailed study of MgII absorption system at high redshift (z > 2.5) where the MgII doublet shifts into the near-infrared in the observer's frame. The spectra of the lensed QSO pair A and B with 0.38 arcsec separation were resolved in some exposure frames under excellent seeing condition. We extracted the MgII doublet spectra of A and B separatel...

  9. $Ly \\alpha$ Fluorescent Excitation of FeII in Active Galactic Nuclei

    CERN Document Server

    Sigut, T A A; Pradhan, Anil K.

    1998-01-01

    We have calculated FeII emission line strengths for Active Galactic Nuclei Broad-Line Regions using precise radiative transfer and Iron Project atomic data. We improve the treatment of all previously considered excitation mechanisms for the FeII emission, continuum fluorescence, collisional excitation, fluorescence by self-overlap among the iron lines, and fluorescent excitation by Lyman-alpha. We demonstrate that Lyman-alpha fluorescence is of fundamental importance in determining the strength of the FeII emission. In addition to enhancing the ultraviolet and optical FeII flux, Lyman-alpha fluorescence also results in significant near-infrared FeII emission in the 8500-9500 Angstrom wavelength range. New observations are suggested to probe this effect in strong FeII emitting quasars.

  10. Evidence for Power Law in the Spectrum of the Coronal Ly-alpha Line

    Science.gov (United States)

    Telloni, Daniele; Antonucci, Ester; Bruno, Roberto; D'Amicis, Raffaella

    Long time series of the intensity of the hydrogen Lyα line revealed the existence of f-2 power spectra in the corona at low and mid latitudes and very close to the Sun, at 1.7 solar radii. These observations are performed with the UltraViolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SoHO). A preliminary analysis indicates that this scaling extends for more than a decade and terminates at higher frequencies with a flat spectrum indicating the presence of white-noise fluctuations. The frequency corresponding to the knee which separates these two different spectral regimes moves to lower and lower values for observations performed at higher and higher heliographic latitudes. Low-frequency power spectra with a f-2 dependence may be due rapid changes (jumps) in the time series. If these coherent structures are removed from the time series, hydrogen coronal intensity power spectra seem to show a power law following the f-1 scaling which would suggest that 1/f interplanetary noise originates in corona.

  11. Similarities and uniqueness of Ly$\\alpha$ emitters among star-forming galaxies at z=2.5

    CERN Document Server

    Shimakawa, Rhythm; Shibuya, Takatoshi; Kashikawa, Nobunari; Tanaka, Ichi; Matsuda, Yuichi; Tadaki, Ken-ichi; Koyama, Yusei; Hayashi, Masao; Suzuki, Tomoko L; Yamamoto, Moegi

    2016-01-01

    We conducted a deep narrow-band imaging survey with the Subaru Prime Focus Camera on the Subaru Telescope and constructed a sample of Ly$\\alpha$ emitters (LAEs) at z=2.53 in the UDS-CANDELS field where a sample of H$\\alpha$ emitters (HAEs) at the same redshift is already obtained from our previous narrow-band observation at NIR. The deep narrow-band and multi broadband data allow us to find LAEs of stellar masses and star-formation rates (SFRs) down to $\\gtrsim$$10^8$ M$_\\odot$ and $\\gtrsim$0.2 M$_\\odot$/yr, respectively. We show that the LAEs are located along the same mass-SFR sequence traced by normal star-forming galaxies such as HAEs, but towards a significantly lower mass regime. Likewise, LAEs seem to share the same mass--size relation with typical star-forming galaxies, except for the massive LAEs, which tend to show significantly compact sizes. We identify a vigorous mass growth in the central part of LAEs: the stellar mass density in the central region of LAEs increases as their total galaxy mass gr...

  12. The LyAlpha Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage

    CERN Document Server

    Martin, Crystal L; Henry, Alaina; Soto, Kurt T; Danforth, Charles W; Wong, Joseph

    2015-01-01

    We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect H Lyman alpha emission from 8 ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the H Lyman alpha profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding -1000 km/s in three HII-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the H Lyman alpha line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The H Lyman alpha attenuation (as measured in the COS aperture) ranges from that ...

  13. Confirmation of a Steep Luminosity Function for Ly alpha Emitters at z 5.7: a Major Component of Reionization

    Science.gov (United States)

    Dressler, Alan; Henry, Alaina L.; Martin, Crystal L.; Sawicki, Marcin; McCarthy, Patrick; Villaneuva, Edward

    2014-01-01

    We report the first direct and robust measurement of the faint-end slope of the Ly-alpha emitter (LAE) luminosity function at z = 5.7. Candidate LAEs from a low-spectral-resolution blind search with IMACS on Magellan- Baade were targeted at higher resolution to distinguish high redshift LAEs from foreground galaxies. All but 2 of our 42 single-emission-line systems are fainter than F = 2.0×10(exp-17) ergs s(exp-1) cm(exp-2), making these the faintest emission-lines observed for a z = 5.7 sample with known completeness, an essential property for determining the faint end slope of the LAE luminosity function. We find 13 LAEs as compared to 29 foreground galaxies, in very good agreement with the modeled foreground counts predicted in Dressler et al. (2011a) that had been used to estimate a faint-end slope of alpha = -2.0 for the LAE luminosity function. A 32% LAE fraction, LAE/(LAE+foreground) within the flux interval F = 2-20 × 10(exp-18) ergs s(exp-1) cm(exp-2) constrains the faint end slope of the luminosity function to -1.95 greater than alpha greater than -2.35 (1 delta). We show how this steep LF should provide, to the limit of our observations, more than 20% of the flux necessary to maintain ionization at z = 5.7, with a factor-of-ten extrapolation in flux reaching more than 55%. We suggest that this bodes well for a comparable contribution by similar, low-mass star forming galaxies at higher-redshift - within the reionization epoch at z greater than approximately 7, only 250 Myr earlier - and that such systems provide a substantial, if not dominant, contribution to the late-stage reionization of the IGM.

  14. The GLARE Survey II. Faint z=6 Ly-alpha Line Emitters in the HUDF

    CERN Document Server

    Stanway, Elizabeth R; Glazebrook, Karl; Abraham, Roberto G; Rhoads, James; Malhotra, Sangeeta; Crampton, David; Colless, Matthew; Chiu, Kuenley; 10.1111/j.1365-2966.2007.11469.x

    2008-01-01

    The galaxy population at z~6 has been the subject of intense study in recent years, culminating in the Hubble Ultra Deep Field (HUDF) -- the deepest imaging survey yet. A large number of high redshift galaxy candidates have been identified within the HUDF, but until now analysis of their properties has been hampered by the difficulty of obtaining spectroscopic redshifts for these faint galaxies. Our ''Gemini Lyman-Alpha at Reionisation Era'' (GLARE) project has been designed to undertake spectroscopic follow up of faint (z'5.5, and a further nine possible line emitters with detections at lower significance. We also place tight constraints on the equivalent width of Lyman-alpha emission for a further ten i'-drop galaxies and examine the equivalent width distribution of this faint spectroscopic sample of z~6 galaxies. We find that the fraction of galaxies with little or no emission is similar to that at z~3, but that the z~6 population has a tail of sources with high rest frame equivalent widths. Possible expla...

  15. Time-Dependent Corrections to the Ly-alpha Escape Probability During Cosmological Hydrogen Recombination

    CERN Document Server

    Chluba, J

    2008-01-01

    In this paper we consider the effects connected with the detailed radiative transfer during the epoch of cosmological recombination on the ionization history of our Universe. We focus on the escape of photons from the hydrogen Lyman-alpha resonance at redshifts 600<~z<~2000, one of two key mechanisms defining the rate of cosmological recombination. We approach this problem within the standard formulation, and corrections due to two-photon interactions are deferred to another paper. As a main result we show here that within a non-stationary approach to the escape problem the resulting correction in the free electron fraction, N_e, is about ~1.6-1.8% in the redshift range 800<~z<~1200. Therefore the discussed process results in one of the biggest modification to the ionization history close to the maximum of Thomson-visibility function at z~1100 considered sofar. We prove our results both numerically and analytically, deriving the escape probability, and considering both Lyman-alpha line-emission an...

  16. The Transparency of the Universe Limited by Ly-alpha Clouds

    CERN Document Server

    Schild, R E; Schild, Rudolph E.; Dekker, Marius

    2005-01-01

    The brightnesses of supernovae are commonly understood to indicate that cosmological expansion is accelerating due to dark energy. However the entire discussion presumes a perfectly transparent universe because no effects of reddening associated with the interstellar extinction law are seen. We note that with two kinds of dark matter (baryonic and non-baryonic) strongly dominating the known mass of the universe, it is seriously premature to assume that these dark matter components have not reduced the transmission of the universe for cosmological sources. We show that the long-known $Lyman-\\alpha$ clouds, if nucleated by the population of baryonic dark matter primordial planetoids indicated by quasar microlensing, would act as spherical lenses and achromatically fade cosmologically distant sources. We attempt to estimate the amount of this cosmological fading, but ultimately the calculation is limited by lack of a satisfactory model for the tenuous outer parts of a primordial planetoid. We also consider the e...

  17. IGM Constraints from the SDSS-III/BOSS DR9 Ly-alpha Forest Flux Probability Distribution Function

    CERN Document Server

    Lee, Khee-Gan; Spergel, David N; Weinberg, David H; Hogg, David W; Viel, Matteo; Bolton, James S; Bailey, Stephen; Pieri, Matthew M; Carithers, William; Schlegel, David J; Lundgren, Britt; Palanque-Delabrouille, Nathalie; Suzuki, Nao; Schneider, Donald P; Yeche, Christophe

    2014-01-01

    The Ly$\\alpha$ forest flux probability distribution function (PDF) is an established probe of the intergalactic medium (IGM) astrophysics, especially the temperature-density relationship of the IGM. We measure the flux PDF from 3393 Baryon Oscillations Spectroscopic Survey (BOSS) quasars from SDSS Data Release 9, and compare with mock spectra that include careful modeling of the noise, continuum, and astrophysical uncertainties. The BOSS flux PDFs, measured at $\\langle z \\rangle = [2.3,2.6,3.0]$, are compared with PDFs created from mock spectra drawn from a suite of hydrodynamical simulations that sample the IGM temperature-density relationship, $\\gamma$, and temperature at mean-density, $T_0$, where $T(\\Delta) = T_0 \\Delta^{\\gamma-1}$. We find that a significant population of partial Lyman-limit systems with a column-density distribution slope of $\\beta_\\mathrm{pLLS} \\sim -2$ are required to explain the data at the low-flux end of flux PDF, while uncertainties in the mean \\lya\\ forest transmission affect the...

  18. On the Heterogeneity of Metal-Line and Ly-Alpha Absorption in Galaxy "Halos" at z~0.7

    CERN Document Server

    Churchill, C W; Steidel, C C; Evans, J L; Churchill, Christopher W.; Kacprzak, Glenn G.; Steidel, Charles C.; Evans, Jessica L.

    2006-01-01

    We examine the properties of two galaxy "halos" at z ~ 0.7 in the TON 153 (z_em = 1.01) quasar field. The first absorber-galaxy pair (G1) is a z = 0.672, L_B = 4.3 L*_B, E/S0 galaxy probed at D = 58 kpc. G1 is associated with a remarkable five-component Ly-alpha complex having tau_LL < 0.4, W_r(Lya) = 2.8 A, and a velocity spread of v = 1420 km/s. We find no MgII, CIV, NV, nor OVI absorption in these clouds and infer metallicity upper limits of -3 < log(Z/Z_sun) < -1, depending upon assumptions of photoionized or collisionally ionized gas. The second absorber-galaxy pair (G2) is a z = 0.661, L_B = 1.8 L*_B, Sab galaxy probed at D = 103 kpc. G2 is associated with metal--enriched (log Z/Z_sun ~ -0.4) photoionized gas having N(HI) ~ 18.3 and a velocity spread of v = 200 km/s. The very different G1 and G2 systems both have gas-galaxy properties inconsistent with the standard luminosity dependent galaxy "halo" model commonly invoked for quasar absorption line surveys. We emphasize that mounting evidence i...

  19. Measuring the Halo Mass of z=3 Damped Ly-alpha Absorbers from the Absorber-Galaxy Cross-correlation

    CERN Document Server

    Bouche, N; Weinberg, D H; Katz, N; Davé, R; Lowenthal, J D; Bouche, Nicolas; Gardner, Jeffrey P.; Weinberg, David H.; Katz, Neal; Dave, Romeel; Lowenthal, James D.

    2005-01-01

    [Abridged] We test the reliability of a method to measure the mean halo mass of Damped Ly-alpha absorbers (DLAs). The method is based on measuring the ratio of the cross-correlation between DLAs and galaxies to the auto-correlation of the galaxies themselves ($w_{\\rm dg}/w_{\\rm gg}$), which is (in linear theory) the ratio of their bias factor. This is shown to be true irrespective of the galaxy redshift distribution, provided that one uses the same galaxies for the two correlation functions. The method is applicable to all redshifts. Here, we focus on z=3 DLAs and we demonstrate that the method robustly constrains the mean DLA halo mass using smoothed particle hydrodynamics (SPH) cosmological simulations. If we use the bias formalism of Mo & White (2002) with the DLA and galaxy mass distributions of these simulations, we predict a bias ratio of 0.771. Direct measurement from the simulations of $w_{\\rm dg}/w_{\\rm gg}$ st yields a ratio of 0.73+/-0.08, in excellent agreement with that prediction. Equivalent...

  20. The Influence of the Photoionizing Radiation Spectrum on Metal-Line Ratios in Ly $\\alpha$ Forest Clouds

    CERN Document Server

    Giroux, M L; Giroux, Mark L.

    1997-01-01

    Recent measurements of Si IV/C IV ratios in the high-redshift Ly-alpha forest (Songaila & Cowie, AJ, 112, 335 [1996a]; Savaglio et al., A&A, in press [1997]) have opened a new window on chemical enrichment and the first generations of stars. However, the derivation of accurate Si/C abundances requires reliable ionization corrections, which are strongly dependent on the spectral shape of the metagalactic ionizing background and on the ``local effects'' of hot stars in nearby galaxies. Recent models have assumed power-law quasar ionizing backgrounds plus a decrement at 4 Ryd to account for He II attenuation in intervening clouds. However, we show that realistic ionizing backgrounds based on cosmological radiative transfer models produce more complex ionizing spectra between 1-5 Ryd that are critical to interpreting ions of Si and C. We also make a preliminary investigation of the effects of He II ionization front non-overlap. Because the attenuation and re-emission by intervening clouds enhance Si IV re...

  1. Dust-to-metal ratios in Damped Lyman-alpha absorbers: Fresh clues to the origins of dust and optical extinction towards gamma-ray bursts

    CERN Document Server

    De Cia, A; Savaglio, S; Schady, P; Vreeswijk, P M

    2013-01-01

    Motivated by the anomalous dust-to-metal ratios (DTM) derived in the literature for gamma-ray burst (GRB) damped Ly-alpha absorbers (DLAs), we measure these ratios using the dust-depletion pattern observed in UV/optical afterglow spectra, associated with the interstellar medium (ISM) at the GRB host-galaxy redshifts. Our sample consists of 20 GRB absorbers and a comparison sample of 72 QSO-DLAs, overall at redshift 1.2 14.7, above which several QSO-DLAs reveal H2, making GRB-DLAs promising candidates for molecular research.

  2. Exploiting 21cm - Ly$\\alpha$ emitter synergies: constraints on reionization

    CERN Document Server

    Hutter, Anne; Müller, Volker; Trott, Cathryn

    2016-01-01

    We couple a $z \\simeq 6.6$ hydrodynamical simulation (GADGET-2) with a radiative transfer code (pCRASH) and a dust model to simultaneously obtain the 21cm emission from the spin-flip transition of neutral hydrogen (HI) as well as the sub-population of galaxies visible as Lyman Alpha Emitters (LAEs). Cross-correlating 21cm data with the underlying galaxy population, and especially the subset visible as LAEs, our aim is to constrain both the average intergalactic medium (IGM) ionization state ($\\langle \\chi_{HI} \\rangle$) and the reionization topology (outside-in versus inside-out). We find that LAEs occupy the densest and most-ionized regions resulting in a very strong anti-correlation between the LAEs and the 21cm emission. Within errors, a 1000h SKA-LOW1 - Subaru Hyper Suprime Cam experiment can provide exquisite constraints on $\\langle \\chi_{HI} \\rangle$, allowing us to distinguish between IGM ionization levels of 50%, 25%, 10% and fully ionized at scales $\\leq 10$ comoving Mpc. Our results support the insi...

  3. Illuminating gas in-/outflows in the MUSE deepest fields: discovery of Ly-alpha nebulae around forming galaxies at z~3.3

    CERN Document Server

    Vanzella, E; Gronke, M; Karman, W; Caminha, G B; Dijkstra, M; Rosati, P; De Barros, S; Caputi, K; Grillo, C; Tozzi, P; Meneghetti, M; Mercurio, A; Gilli, R

    2016-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals a complex structure with a spatially-varying double peaked Ly-alpha emission. Overall, the spectral profiles of the two Ly-alpha nebulae are remarkably similar, both showing a prominent blue emission, more intense and slightly broader than the red peak. From the first nebula, located in the HUDF, no X-ray emission has been detected, disfavoring the possible presence of AGNs. Spectroscopic redshifts have been derived for 11 galaxies within two arcsec from the nebula and spanning the redshift range 1.037

  4. PRESENT-DAY DESCENDANTS OF z = 3 Ly{alpha}-EMITTING GALAXIES IN THE MILLENNIUM-II HALO MERGER TREES

    Energy Technology Data Exchange (ETDEWEB)

    Walker-Soler, Jean P.; Gawiser, Eric [Physics and Astronomy Department, Rutgers University, Piscataway, NJ 08854 (United States); Bond, Nicholas A. [Goddard Space Flight Center, Astrophysics Science Division, Observational Cosmology Laboratory, Greenbelt, MD 20771 (United States); Padilla, Nelson; Francke, Harold, E-mail: jpwalker@physics.rutgers.edu [Pontificia Universidad Catolica de Chile, Facultad de Fisica, Santiago (Chile)

    2012-06-20

    Using the Millennium-II Simulation dark matter sub-halo merger histories, we created mock catalogs of Ly{alpha}-emitting (LAE) galaxies at z = 3.1 to study the properties of their descendants. Several models were created by selecting the sub-halos to match the number density and typical dark matter mass determined from observations of these galaxies. We used mass-based and age-based selection criteria to study their effects on descendant populations at z {approx_equal} 2, 1, and 0. For the models that best represent LAEs at z = 3.1, the z = 0 descendants have a median dark matter halo mass of 10{sup 12.7} M{sub Sun }, with a wide scatter in masses (50% between 10{sup 11.8} and 10{sup 13.7} M{sub Sun }). Our study differentiated between central and satellite sub-halos and found that {approx}55% of z = 0 descendants are central sub-halos with M{sub Median} {approx} 10{sup 12}. This confirms that central z = 0 descendants of z = 3.1 LAEs have halo masses typical of L*-type galaxies. The satellite sub-halos reside in group/cluster environments with dark matter masses around 10{sup 14} M{sub Sun }. The median descendant mass is robust to various methods of age determination, but it could vary by a factor of five due to current observational uncertainties in the clustering of LAEs used to determine their typical z = 3.1 dark matter mass.

  5. Ultraviolet Broad Absorption Features and the Spectral Energy Distribution of the QSO PG 1351+64

    CERN Document Server

    Zheng, W; Wang, J X; Brotherton, M S; Oegerle, W R; Blair, W P; Davidsen, A F; Green, R F; Hutchings, J B; Kaiser, M E

    2001-01-01

    We present a moderate-resolution (~20 km/s) spectrum of the mini broad-absorption-line QSO PG1351+64 between 915-1180 A, obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Additional spectra at longer wavelengths were also obtained with the HST and ground-based telescopes. Broad absorption is present on the blue wings of CIII 977, Ly-beta, OVI 1032,1038, Ly-alpha, NV 1238,1242, SiIV 1393,1402, and CIV 1548,1450. The absorption profile can be fitted with five components at velocities of ~ -780, -1049, -1629, -1833, and -3054 km/s with respect to the emission-line redshift of z = 0.088. All the absorption components cover a large fraction of the continuum source as well as the broad-line region. The OVI emission feature is very weak, and the OVI/Lyalpha flux ratio is 0.08, one of the lowest among low-redshift active galaxies and QSOs. The UV continuum shows a significant change in slope near 1050 A in the restframe. The steeper continuum shortward of the Lyman limit extrapolates well to the observ...

  6. TNF-alpha-dependent regulation of acute pancreatitis severity by Ly-6C(hi) monocytes in mice.

    Science.gov (United States)

    Perides, George; Weiss, Eric R; Michael, Emily S; Laukkarinen, Johanna M; Duffield, Jeremy S; Steer, Michael L

    2011-04-15

    The roles of monocytes/macrophages and their mechanisms of action in the regulation of pancreatitis are poorly understood. To address these issues, we have employed genetically altered mouse strains that either express the human diphtheria toxin receptor (DTR) coupled to the CD11b promoter or have global deletion of TNF-α. Targeted, conditional depletion of monocytes/macrophages was achieved by administration of diphtheria toxin (DT) to CD11b-DTR mice. We show that in the absence of DT administration, pancreatitis is associated with an increase in pancreatic content of Ly-6C(hi) monocytes/macrophages but that this response is prevented by prior administration of DT to CD11b-DTR mice. DT administration also reduces pancreatic edema and acinar cell injury/necrosis in two dissimilar experimental models of acute pancreatitis (a secretagogue-induced model and a model elicited by retrograde pancreatic duct infusion of sodium taurocholate). In the secretagogue-elicited model, the DT-induced decrease in pancreatitis severity is reversed by adoptive transfer of purified Ly-6C(hi) monocytes harvested from non-DT-treated CD11b-DTR mice or by the transfer of purified Ly-6C(hi) monocytes harvested from TNF-α(+/+) donor mice, but it is not reversed by the transfer of Ly-6C(hi) monocytes harvested from TNF-α(-/-) donors. Our studies indicate that the Ly-6C(hi) monocyte subset regulates the severity of pancreatitis by promoting pancreatic edema and acinar cell injury/necrosis and that this phenomenon is dependent upon the expression of TNF-α by those cells. They suggest that therapies targeting Ly-6C(hi) monocytes and/or TNF-α expression by Ly-6C(hi) monocytes might prove beneficial in the prevention or treatment of acute pancreatitis.

  7. THE LYMAN ALPHA REFERENCE SAMPLE. V. THE IMPACT OF NEUTRAL ISM KINEMATICS AND GEOMETRY ON Lyα ESCAPE

    Energy Technology Data Exchange (ETDEWEB)

    Rivera-Thorsen, Thøger E.; Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Adamo, Angela [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Orlitová, Ivana [Astronomical Institute, Academy of Sciences of the Czech Republic, Boční II, CZ-14131 Prague (Czech Republic); Verhamme, Anne; Schaerer, Daniel [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel [Centro de Astrobiología (CSIC–INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Otí-Floranes, Héctor [Instituto de Astronomía, Universidad Nacional Autónoma de México, Apdo. Postal 106, B. C. 22800 Ensenada (Mexico); Atek, Hakim [Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Herenz, E. Christian [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel, E-mail: trive@astro.su.se [Institut d’Astrophysique de Paris, UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); and others

    2015-05-20

    We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyα Reference Sample; a sample of strongly star-forming galaxies at low redshifts (0.028 < z < 0.18). We compare the derived properties to global properties derived from multi-band imaging and 21 cm H i interferometry and single-dish observations, as well as archival optical SDSS spectra. Besides the Lyα line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line of sight velocity. Furthermore, we show how this, in combination with the precise determination of systemic velocity and good Lyα spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the “picket fence” model named by Heckman et al. We find that no one single effect dominates in governing Lyα radiative transfer and escape. Lyα escape in our sample coincides with a maximum velocity-binned covering fraction of ≲0.9 and bulk outflow velocities of ≳50 km s{sup −1}, although a number of galaxies show these characteristics and yet little or no Lyα escape. We find that Lyα peak velocities, where available, are not consistent with a strong backscattered component, but rather with a simpler model of an intrinsic emission line overlaid by a blueshifted absorption profile from the outflowing wind. Finally, we find a strong anticorrelation between Hα equivalent width and maximum velocity-binned covering factor, and propose a heuristic explanatory model.

  8. Effects of LY117018 and the estrogen analogue, 17alpha-ethinylestradiol, on vascular reactivity, platelet aggregation, and lipid metabolism in the insulin-resistant JCR:LA-cp male rat: role of nitric oxide.

    Science.gov (United States)

    Russell, J C; McKendrick, J D; Dubé, P J; Dolphin, P J; Radomski, M W

    2001-01-01

    The JCR:LA-cp rat is obese and insulin resistant and develops a major vasculopathy, with associated ischemic damage to the heart. Male rats were treated with 17alpha-ethinylestradiol (EE), LY117018, and/or the nitric oxide synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME). LY117018 decreased plasma cholesterol esters, with a 40% reduction in total cholesterol. EE increased triglyceride levels and modestly decreased cholesterol esters. L-NAME increased blood pressure and aortic contractile sensitivity to phenylephrine and inhibited acetylcholine-induced relaxation. LY117018 decreased the force of contraction. The L-NAME-mediated increase in force of contraction and decrease in response to acetylcholine was inhibited by LY117018. L-NAME-induced hypertension was prevented by LY117018. Platelet aggregation was not different between obese and lean rats and was unaffected by L-NAME. LY117018, both in the absence and presence of L-NAME, inhibited platelet aggregation. The effects of LY117018 are apparently mediated through both NO-dependent and -independent mechanisms. The changes induced by EE and LY117018 may reflect the activation of multiple mechanisms, both estrogen receptor-dependent and -independent. The changes induced by LY117018 are significant and may prove to be cardioprotective in the presence of the insulin resistance syndrome.

  9. Discovery of a broad O VIII Ly alpha line in the ultra-compact X-ray binary 4U 1543-624

    CERN Document Server

    Madej, O K

    2010-01-01

    We report the discovery of a broad emission feature at ~0.7 keV in the spectra of the ultra-compact X-ray binary 4U 1543-624, obtained with the high-resolution spectrographs of the XMM-Newton and Chandra satellites. We confirm the presence of the feature in the broad band MOS2 spectrum of the source. As suggested before in the literature, the donor star in this source is a CO or ONe white dwarf, which transfers oxygen-rich material to the accretor, conceivably a neutron star. The X-rays reprocessed in this oxygen-rich accretion disc could give a reflection spectrum with O VIII Ly alpha as the most prominent emission line. Apart from the feature at ~0.7 keV we confirm the possible presence of a weak emission feature at ~6.6 keV, which was reported in the literature for this data set. We interpret the feature at ~0.7 keV and ~6.6 keV as O VIII Ly alpha and Fe K alpha emission respectively, caused by X-rays reflected off the accretion disc in the strong gravitational field close to the accretor.

  10. Keck Spectroscopy of Lyman-break Galaxies and its Implications for the UV-continuum and Ly_alpha Luminosity Functions at z>6

    CERN Document Server

    Jiang, Linhua; Kashikawa, Nobunari; Walth, Gregory; Matsuda, Yuichi; Shimasaku, Kazuhiro; Nagao, Tohru; Ota, Kazuaki; Ouchi, Masami

    2011-01-01

    We present Keck spectroscopic observations of z>6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z'=27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Ly_alpha emission lines at 6100 A. This well-defined spectroscopic sample spans a UV-continuum luminosity range of -21.8~6.2 after we correct for sample incompleteness. We find that our measurement of the UV LF is consistent with the results of previous studies based on photometric LBG samples at 56.

  11. Thirty-four New, High-Probability, Damped Ly-alpha Absorbers at Redshift z=[0.42, 0.70

    CERN Document Server

    Turnshek, David A; Rao, Sandhya M; Hamilton, Timothy S; Sardane, Gendith M; Held, Ryan

    2014-01-01

    Quasar damped Ly-alpha (DLA) absorption line systems with redshifts z<1.65 are used to trace neutral gas over approximately 70 per cent of the most recent history of the Universe. However, such systems fall in the UV and are rarely found in blind UV spectroscopic surveys. Therefore, it has been difficult to compile a moderate-sized sample of UV DLAs in any narrow cosmic time interval. However, DLAs are easy to identify in low-resolution spectra because they have large absorption rest equivalent widths. We have performed an efficient strong-MgII-selected survey for UV DLAs at redshifts z=[0.42,0.70] using HST's low-resolution ACS-HRC-PR200L prism. This redshift interval covers ~1.8 Gyr in cosmic time, i.e., t~[7.2,9.0] Gyrs after the Big Bang. A total of 95 strong MgII absorption-line systems identified in SDSS spectra were successfully observed with the prism at the predicted UV wavelengths of Ly-alpha absorption. We found that 33 of the 95 systems had a significant probability of being DLAs. One additiona...

  12. Three-dimensional radiative transfer simulations of the scattering polarization of the hydrogen Ly$\\alpha$ line in a MHD model of the chromosphere-corona transition region

    CERN Document Server

    Stepan, Jiri; Leenaarts, Jorrit; Carlsson, Mats

    2015-01-01

    Probing the magnetism of the upper solar chromosphere requires measuring and modeling the scattering polarization produced by anisotropic radiation pumping in UV spectral lines. Here we apply PORTA (a novel radiative transfer code) to investigate the hydrogen Ly$\\alpha$ line in a 3D model of the solar atmosphere resulting from a state of the art MHD simulation. At full spatial resolution the linear polarization signals are very significant all over the solar disk, with a large fraction of the field of view showing line-center amplitudes well above the 1% level. Via the Hanle effect the line-center polarization signals are sensitive to the magnetic field of the model's transition region, even when its mean field strength is only 15 G. The breaking of the axial symmetry of the radiation field produces significant forward-scattering polarization in Ly$\\alpha$, without the need of an inclined magnetic field. Interestingly, the Hanle effect tends to decrease such forward-scattering polarization signals in most of ...

  13. A young star-forming galaxy at z = 3.5 with an extended Ly\\,$\\alpha$ halo seen with MUSE

    CERN Document Server

    Patrício, Vera; Verhamme, Anne; Wisotzki, Lutz; Brinchmann, Jarle; Turner, Monica L; Christensen, Lise; Weilbacher, Peter M; Blaizot, Jérémy; Bacon, Roland; Contini, Thierry; Lagattuta, David; Cantalupo, Sebastiano; Clément, Benjamin; Soucail, Geneviève

    2015-01-01

    Spatially resolved studies of high redshift galaxies, an essential insight into galaxy formation processes, have been mostly limited to stacking or unusually bright objects. We present here the study of a typical (L$^{*}$, M$_\\star$ = 6 $\\times 10^9$ $M_\\odot$) young lensed galaxy at $z=3.5$, observed with MUSE, for which we obtain 2D resolved spatial information of Ly$\\alpha$ and, for the first time, of CIII] emission. The exceptional signal-to-noise of the data reveals UV emission and absorption lines rarely seen at these redshifts, allowing us to derive important physical properties (T$_e\\sim$15600 K, n$_e\\sim$300 cm$^{-3}$, covering fraction f$_c\\sim0.4$) using multiple diagnostics. Inferred stellar and gas-phase metallicities point towards a low metallicity object (Z$_{\\mathrm{stellar}}$ = $\\sim$ 0.07 Z$_\\odot$ and Z$_{\\mathrm{ISM}}$ $<$ 0.16 Z$_\\odot$). The Ly$\\alpha$ emission extends over $\\sim$10 kpc across the galaxy and presents a very uniform spectral profile, showing only a small velocity shift...

  14. Structure-function relationships in the receptor for urokinase-type plasminogen activator. Comparison to other members of the Ly-6 family and snake venom alpha-neurotoxins

    DEFF Research Database (Denmark)

    Ploug, M; Ellis, V

    1994-01-01

    Plasminogen activation is regulated by the interaction between urokinase-type plasminogen activator (uPA) and its specific glycolipid-anchored cell surface receptor (uPAR). uPAR is composed of three homologous domains and is the only multi-domain member of the Ly-6 family of glycolipid-anchored m......Plasminogen activation is regulated by the interaction between urokinase-type plasminogen activator (uPA) and its specific glycolipid-anchored cell surface receptor (uPAR). uPAR is composed of three homologous domains and is the only multi-domain member of the Ly-6 family of glycolipid......-anchored membrane proteins. Recent evidence has highlighted similarities between the individual domains of uPAR and the large family of secreted, single domain snake venom alpha-neurotoxins, suggesting that uPAR may adopt the same gross folding pattern as these structurally well characterized proteins. Structural...... aspects of the binding between alpha-neurotoxins and the acetylcholine receptor may have a major influence on future studies of the interaction between uPA and uPAR....

  15. Dust Extinction Curves and Ly-$\\alpha$ Forest Flux Deficits for Use in Modeling GRB Afterglows and All Other Extragalactic Point Sources

    CERN Document Server

    Reichart, D E

    1999-01-01

    Since gamma-ray burst afterglows were first detected in 1997, the relativistic fireball model has emerged as the leading theoretical explanation of the afterglows. In this paper, we present a very general, Bayesian inference formalism with which this, or any other, afterglow model can be tested, and with which the parameter values of acceptable models can be constrained, given the available photometry. However, before model comparison or parameter estimation can be attempted, one must also consider the physical processes that affect the afterglow as it propagates along the line of sight from the burst source to the observer. Namely, how does extinction by dust, both in the host galaxy and in our galaxy, and absorption by the Ly-alpha forest and by H I in the host galaxy, change the intrinsic spectrum of the afterglow? Consequently, we also present in this paper a very general, eight-parameter dust extinction curve model, and a two-parameter model of the Ly-alpha forest flux deficit versus redshift distributio...

  16. Physical Properties of Spectroscopically-Confirmed Galaxies at $z\\ge6$. III. Stellar Populations from SED Modeling with Secure Ly$\\alpha$ Emission and Redshifts

    CERN Document Server

    Jiang, Linhua; Cohen, Seth H; Egami, Eiichi; Windhorst, Rogier A; Fan, Xiaohui; Dave, Romeel; Kashikawa, Nobunari; Mechtley, Matthew; Ouchi, Masami; Shimasaku, Kazuhiro; Clement, Benjamin

    2015-01-01

    We present a study of stellar populations in a sample of spectroscopically-confirmed Lyman-break galaxies (LBGs) and Ly$\\alpha$ emitters (LAEs) at $5.7Ly$\\alpha$ flux, we are able to break the strong degeneracy of model spectra between young galaxies with prominent nebular emission and older galaxies with strong Balmer breaks. The results show that our galaxies cover a wide range of ages from several to a few hundred million years (Myr), and a wide range of stellar masses from $\\sim10^8$ to $\\sim10^{11}$ $M_{\\odot}$. These galaxies can be roughly divided into an `old' subsample and a `young' subsample. The `old' subsample consists of galaxies older than 100 Myr,...

  17. An HST/COS Observation of Broad Ly$\\alpha$ Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309

    CERN Document Server

    Fang, Taotao; Buote, David A; Stocke, John T; Shull, J Michael; Canizares, Claude R; Gastaldello, Fabio

    2014-01-01

    Weak spectral features in BL Lacertae objects (BL Lac) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly$\\alpha$ emission line was detected. This is the fourth detection of a weak Ly$\\alpha$ emission feature in the ultraviolet (UV) band in the so-called "high energy peaked BL Lacs", after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor ($\\Gamma$) of the relativistic jet to be $\\geq 8.1$ with a maximum viewing angle of 3.6$^\\circ$. The derived $\\Gamma$ is somewhat larger than previous measurements of $\\Gamma \\approx 3 - 5$, implying a covering factor of $\\sim$ 3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be $\\sim 10^{-5}\\rm\\ M_{\\odot}$. ...

  18. AGN Physics from QSO Clustering

    CERN Document Server

    Croom, S; Shanks, T; Outram, P J; Smith, R; Miller, L; Loaring, N; Kenyon, S; Couch, W; Croom, Scott; Boyle, Brian; Shanks, Tom; Outram, Phil; Smith, Robert; Miller, Lance; Loaring, Nicola; Kenyon, Suzanne; Couch, Warrick

    2003-01-01

    We review the current status of QSO clustering measurements, particular with respect to their relevance in understanding AGN physics. Measurements based on the 2dF QSO Redshift Survey (2QZ) find a scale length for QSO clustering of s_0=5.76(+0.17-0.27) h-1 Mpc at a redshift ~1.5, very similar to low redshift galaxies. There is no evidence of evolution in the clustering of QSOs from z~0.5 to z~2.2. This lack of evolution and low clustering amplitude suggests a short life time for AGN activity of the order ~10^6-10^7 years. Large surveys such at the 2QZ and SDSS also allow the the study of QSO environments in 3D for the first time (at least at low redshift), early results from this work seem to show no difference between the environments of QSOs and normal galaxies. Future studies e.g. measuring clustering as a function of black hole mass, and deep QSO surveys should provide further insight into the formation and evolution of AGN.

  19. A cold metal poor cloud traced by a weak MgII absorption at z~0.45. First detection of SiI, CaI and FeI in a QSO absorber

    CERN Document Server

    D'Odorico, Valentina

    2007-01-01

    We present the observations of a weak MgII absorption system detected at z~0.452 in the UVES high resolution spectrum of the QSO HE0001-2340. The weakest of the two MgII components forming the system shows associated absorptions due to SiI, CaI and FeI observed for the first time in a QSO spectrum. We investigate the nature of this absorber by comparing its properties with those of different classes of absorbers (weak MgII, Damped Ly-alpha systems and local interstellar clouds) and reproducing its ionization conditions with photoionization models. The observed absorber belongs to the class of weak MgII systems on the basis of its equivalent width, however the relative strength of commonly observed transitions deviates significantly from those of the above mentioned absorbers. A rough estimate of the probability to cross such a system with a QSO line of sight is P~0.03. The presence of rare neutral transitions suggests that the cloud is shielded by a large amount of neutral Hydrogen. A detailed comparison of t...

  20. A coronagraphic absorbing cloud reveals the narrow-line region and extended Lyman-$\\alpha$ emission of QSO J0823+0529

    CERN Document Server

    Fathivavsari, Hassan; Noterdaeme, Pasquier; Pâris, Isabelle; Finley, Hayley; López, Sebastian; Srianand, Raghunathan; Sánchez, Paula

    2015-01-01

    We report long-slit spectroscopic observations of the quasar SDSS J082303.22+052907.6 ($z_{\\rm CIV}$$\\sim$3.1875), whose Broad Line Region (BLR) is partly eclipsed by a strong damped Lyman-$\\alpha$ (DLA; log$N$(HI)=21.7) cloud. This allows us to study the Narrow Line Region (NLR) of the quasar and the Lyman-$\\alpha$ emission from the host galaxy. Using CLOUDY models that explain the presence of strong NV and PV absorption together with the detection of SiII$^*$ and OI$^{**}$ absorption in the DLA, we show that the density and the distance of the cloud to the quasar are in the ranges 180 $$ $r_0$ $>$230 pc, respectively. Sizes of the neutral($\\sim$2-9pc) and highly ionized phases ($\\sim$3-80pc) are consistent with the partial coverage of the CIV broad line region by the CIV absorption from the DLA (covering factor of $\\sim$0.85). We show that the residuals are consistent with emission from the NLR with CIV/Lyman-$\\alpha$ ratios varying from 0 to 0.29 through the profile. Remarkably, we detect extended Lyman-$\\...

  1. Bright and Faint Ends of Ly$\\alpha$ Luminosity Functions at $\\textit{z} = 2$ Determined by the Subaru Survey: Implications for AGN, Magnification Bias, and ISM HI Evolution

    CERN Document Server

    Konno, Akira; Nakajima, Kimihiko; Duval, Florent; Kusakabe, Haruka; Ono, Yoshiaki; Shimasaku, Kazuhiro

    2015-01-01

    We present the Lya luminosity functions (LFs) derived by our deep Subaru narrowband survey that identifies a total of 3,137 Lya emitters (LAEs) at $z = 2.2$ in five independent blank fields. The sample of these LAEs is the largest, to date, and covers a very wide Lya luminosity range of $\\log L_{Ly\\alpha} = 41.7-44.4$ erg s$^{-1}$. We determine the Lya LF at $z = 2.2$ with unprecedented accuracies, and obtain the best-fit Schechter parameters of $L^{*}_{Ly\\alpha} = 5.29^{+1.67}_{-1.13} \\times 10^{42}$ erg s$^{-1}$, $\\phi^{*}_{Ly\\alpha} = 6.32^{+3.08}_{-2.31} \\times 10^{-4}$ Mpc$^{-3}$, and $\\alpha = -1.75^{+0.10}_{-0.09}$ showing a steep faint-end slope. We identify a significant hump at the LF bright end ($\\log L_{Ly\\alpha} > 43.4$ erg s$^{-1}$). Because all of the LAEs in the bright-end hump have (a) bright counterpart(s) either in the X-ray, UV, or radio data, this bright-end hump is not made by gravitational lensing magnification bias but AGNs. These AGNs allow us to derive the AGN UV LF at $z \\sim 2$ dow...

  2. The scattering polarization of the Ly-alpha lines of H I and He II taking into account PRD and J-state interference effects

    CERN Document Server

    Belluzzi, Luca; Stepan, Jiri

    2012-01-01

    Recent theoretical investigations have pointed out that the cores of the Ly-alpha lines of H I and He II should show measurable scattering polarization signals when observing the solar disk, and that the magnetic sensitivity, through the Hanle effect, of such linear polarization signals is suitable for exploring the magnetism of the solar transition region. Such investigations were carried out in the limit of complete frequency redistribution (CRD) and neglecting quantum interference between the two upper J-levels of each line. Here we relax both approximations and show that the joint action of partial frequency redistribution (PRD) and J-state interference produces much more complex fractional linear polarization (Q/I) profiles, with large amplitudes in their wings. Such wing polarization signals turn out to be very sensitive to the temperature structure of the atmospheric model, so that they can be exploited for constraining the thermal properties of the solar chromosphere. Finally, we show that the approxi...

  3. Mapping the Dynamics of a Giant Ly-alpha Halo at z=4.1 with MUSE: The Energetics of a Large Scale AGN-Driven Outflow around a Massive, High-Redshift Galaxy

    CERN Document Server

    Swinbank, Mark; Smail, Ian; De Breuck, Carlos; Bacon, Roland; Contini, Thierry; Richard, Johan; Rottgering, Huub; Urritia, Tanya; Venemans, Bram

    2015-01-01

    We present deep MUSE integral-field unit (IFU) spectroscopic observations of the giant (~150 x 80 kpc) Ly-alpha halo around the z=4.1 radio galaxy TNJ J1338-1942. This 9-hr observation maps the two-dimensional kinematics of the Ly-alpha emission across the halo. We identify two HI absorbers which are seen against the Ly-alpha emission, both of which cover the full 150 x 80 kpc extent of the halo and so have covering fractions ~1. The stronger and more blue-shifted absorber (dv~1200 km/s) has dynamics that mirror that of the underlying halo emission and we suggest that this high column material (n(HI) ~ 10^19.4 /cm^2), which is also seen in CIV absorption, represents an out-flowing shell that has been driven by the AGN (or star formation) within the galaxy. The weaker (n(HI)~10^14 /cm^2) and less blue shifted (dv~500 km/s) absorber most likely represents material in the cavity between the out-flowing shell and the Ly-alpha halo. We estimate that the mass in the shell must be of order 10^10 Msol -- a significan...

  4. Ly alpha emissters at z=6.5 in the SSA22 field: An area more neutral or void at the end of the reionization epoch

    CERN Document Server

    Nakamura, E; Hayashino, T; Horie, M; Kousai, K; Fujii, T; Matsuda, Y

    2010-01-01

    We present results of a survey of Lyman $\\alpha$ emitters (LAEs) at $z=6.5$ which is thought to be the final epoch of the cosmic reionization. In a $\\approx530$ arcmin$^2$ deep image of the SSA22 field taken through a narrowband filter NB912 installed in the Subaru/Suprime-Cam, we have found only 14 LAE candidates with $L_{\\rm Ly\\alpha}\\ga3\\times10^{42}$ erg s$^{-1}$. Even applying the same colour selection criteria, the number density of the LAE candidates is a factor of 3 smaller than that found at the same redshift in the Subaru Deep field (SDF). Assuming the number density in the SDF is a cosmic average, the probability to have a number density equal to or smaller than that found in the SSA22 field is only 7% if we consider fluctuation by the large-scale structure (i.e. cosmic variance) and Poisson error. Therefore, the SSA22 field may be a rare void at $z=6.5$. On the other hand, we have found that the number density of $i'$-drop galaxies with $25.5

  5. THE FIRST OBSERVATIONS OF LOW-REDSHIFT DAMPED Ly{alpha} SYSTEMS WITH THE COSMIC ORIGINS SPECTROGRAPH: CHEMICAL ABUNDANCES AND AFFILIATED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Battisti, A. J.; Meiring, J. D.; Tripp, T. M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Prochaska, J. X.; Werk, J. K. [Department of Astronomy and Astrophysics, University of California Observatories-Lick Observatory, UC Santa Cruz, CA 95064 (United States); Jenkins, E. B. [Department of Astrophysical Sciences, Princeton University Observatory, Princeton, NJ 08544 (United States); Lehner, N. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Tumlinson, J.; Thom, C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2012-01-10

    We present Cosmic Origins Spectrograph (COS) measurements of metal abundances in eight 0.083 < z{sub abs} < 0.321 damped Ly{alpha} (DLA) and sub-DLA absorption systems serendipitously discovered in the COS-Halos survey. We find that these systems show a large range in metallicities, with -1.10 < [Z/H] < 0.31, similar to the spread found at higher redshifts. These low-redshift systems on average have subsolar metallicities, but do show a rise in metallicity over cosmic time when compared to higher-redshift systems. We find that the average sub-DLA metallicity is higher than the average DLA metallicity at all redshifts. Nitrogen is underabundant with respect to {alpha}-group elements in all but perhaps one of the absorbers. In some cases, [N/{alpha}] is significantly below the lowest nitrogen measurements in nearby galaxies. Systems for which depletion patterns can be studied show little, if any, depletion, which is characteristic of Milky Way halo-type gas. We also identify affiliated galaxies for three of the sub-DLAs using spectra obtained from a Keck/Low Resolution Imaging Spectrometer (LRIS). None of these sub-DLAs arise in the stellar disks of luminous galaxies; instead, these absorbers may exist in galaxy halos at impact parameters ranging from 38 to 92 kpc. Multiple galaxies are present near two of the sub-DLAs, and galaxy interactions may play a role in the dispersal of the gas. Many of these low-redshift absorbers exhibit simple kinematics, but one sub-DLA has a complicated mix of at least 13 components spread over 150 km s{sup -1}. We find three galaxies near this sub-DLA, which also suggests that galaxy interactions roil the gas. This study reinforces the view that DLAs have a variety of origins, and low-redshift studies are crucial for understanding absorber-galaxy connections.

  6. A hard ionizing spectrum in z=3-4 Ly-alpha emitters with intense [OIII] emission: Analogs of galaxies in the reionization era?

    CERN Document Server

    Nakajima, Kimihiko; Iwata, Ikuru; Inoue, Akio; Kusakabe, Haruka; Ouchi, Masami; Robertson, Brant

    2016-01-01

    We present Keck/MOSFIRE spectra of the diagnostic nebular emission lines [OIII]5007,4959, [OII]3727, and H-beta for a sample of 15 redshift z=3.1-3.7 Ly-alpha emitters (LAEs) and Lyman break galaxies (LBGs). In conjunction with spectra from other surveys, we confirm earlier indications that LAEs have a much higher [OIII]/[OII] line ratio than is seen in similar redshift LBGs. By comparing their distributions on a [OIII]/[OII] versus R23 diagram, we demonstrate that this difference cannot arise solely because of their lower metallicities but most likely is due to a harder ionizing spectrum. Using measures of H-beta and recombination theory, we demonstrate, for a subset of our LAEs, that xi_ion - the number of Lyman continuum photons per UV luminosity - is indeed 0.2-0.5 dex larger than for typical LBGs at similar redshifts. Using photoionization models we estimate the effect this would have on both [OIII]/[OII] and R23 and conclude such a hard spectrum can only partially explain such intense line emission. The...

  7. Radio and millimeter properties of $z \\sim 5.7$ Ly$\\alpha$ emitters in the COSMOS field: limits on radio AGN, submm galaxies, and dust obscuration

    CERN Document Server

    Carilli, C L; Wang, R; Schinnerer, E; Taniguchi, Y; Smolcic, V; Bertoldi, F; Ajiki, M; Nagao, T; Sasaki, S S; Shioya, Y; Aguirre, J E; Blain, A W; Scoville, N Z; Sanders, D B

    2006-01-01

    We present observations at 1.4 and 250 GHz of the $z\\sim 5.7$ Ly$\\alpha$ emitters (LAE) in the COSMOS field found by Murayama et al.. At 1.4 GHz there are 99 LAEs in the lower noise regions of the radio field. We do not detect any individual source down to 3$\\sigma$ limits of $\\sim 30\\mu$Jy beam$^{-1}$ at 1.4 GHz, nor do we detect a source in a stacking analysis, to a 2$\\sigma$ limit of $2.5\\mu$Jy beam$^{-1}$. At 250 GHz we do not detect any of the 10 LAEs that are located within the central regions of the COSMOS field covered by MAMBO ($20' \\times 20'$) to a typical 2$\\sigma$ limit of $S_{250} 6\\times 10^{24}$ W Hz$^{-1}$ in the LAE sample. The radio and millimeter observations also rule out any highly obscured, extreme starbursts in the sample, ie. any galaxies with massive star formation rates $> 1500$ M$_\\odot$ year$^{-1}$ in the full sample (based on the radio data), or 500 M$_\\odot$ year$^{-1}$ for the 10% of the LAE sample that fall in the central MAMBO field. The stacking analysis implies an upper li...

  8. An Observational Pursuit for Population III Stars in a Ly_alpha Emitter at z=6.33 through HeII Emission

    CERN Document Server

    Nagao, T; Maiolino, R; Marconi, A; Taniguchi, Y; Aoki, K; Ajiki, M; Shioya, Y; Nagao, Tohru; Motohara, Kentaro; Maiolino, Roberto; Marconi, Alessandro; Taniguchi, Yoshiaki; Aoki, Kentaro; Ajiki, Masaru; Shioya, Yasuhiro

    2005-01-01

    We present a very deep near-infrared spectroscopic observation of a strong Ly_alpha emitter at z=6.33, SDF J132440.6+273607, which we used to search for HeII 1640. This emission line is expected if the target hosts a significant number of population III stars. Even after 42 ksec of integration with the Subaru/OHS spectrograph, no emission-line features are detected in the JH band, which confirms that SDF J132440.6+273607 is neither an active galactic nucleus nor a low-$z$ emission-line object. We obtained a 2sigma upper-limit of 9.06e-18 ergs/s/cm^2 on the HeII 1640 emission line flux, which corresponds to a luminosity of 4.11e42 ergs/s. This upper-limit on the HeII 1640 luminosity implies that the upper limit on population III star-formation rate is in the range 4.9--41.2 M_sun/yr if population III stars suffer no mass loss, and in the range 1.8--13.2 M_sun/yr if strong mass loss is present. The non-detection of HeII in SDF J132440.6+273607 at z=6.33 may thus disfavor weak feedback models for population III ...

  9. First direct implications for the dust extinction and star formation of typical Ly{\\alpha} emitters from their faint infrared luminosities

    CERN Document Server

    Kusakabe, Haruka; Nakajima, Kimihiko; Ouchi, Masami

    2014-01-01

    Measuring the IR luminosity of galaxies is crucial for reliably deriving their dust extinction and stellar population. By stacking publicly available deep Spitzer/MIPS 24um and Herschel PACS images for 213 z~2.18 Ly alpha Emitters (LAEs) in the GOODS-South, we obtain a strong upper limit to the IR luminosity of typical high-redshift LAEs and constrain the extinction law for the first time. Our 3sigma upper limit L_{TIR} = 1.1 * 10^{10} L_{sun} gives IRX = L_{TIR}/L_{UV} 44%, are both significantly higher than the cosmic averages at the same epoch. We find that the SMC extinction law is consistent with the IRX and the UV slope beta = -1.4^{+0.2}_{-0.2} of our stacked LAE, while the Calzetti law predicts a 3.8 times higher IRX at this beta. SED fitting using the Calzetti law also gives a ~10 times higher SFR than that calculated from the IR and UV luminosities, SFR_{tot}=1.5-3.3 M_{sun}/yr. With the stellar mass 6.3^{+0.8}_{-2.0} *10^8 M_{sun}, our LAEs lie on a lower-mass extrapolation of the star formation ma...

  10. The Spatial, Ionization, and Kinematic Conditions of the z=1.39 Damped Ly-alpha Absorber in Q0957+561 A,B

    CERN Document Server

    Churchill, C W; Charlton, J; Vogt, S S; Churchill, Chris; Mellon, Rick; Charlton, Jane; Vogt, Steve

    2003-01-01

    We examined the sizes of the absorption clouds in a z=1.3911 damped Ly-alpha absorber (DLA) in the double image lensed quasar Q0957+561 A,B (separation 135 pc at the absorber redshift). Using HIRES/Keck spectra, we studied the MgII 2796,2803 doublet, FeII multiplet, and MgI 2853 transition in absorption. We defined six "clouds" in the system of sightline A and seven clouds in the system of sightline B. An examination of the N(v) profiles, using the apparent optical depth method, reveals no clear physical connection between the clouds in A and those in B. The observed column density ratios of all clouds is log[N(MgI)/N(FeII)] ~ -2 across the full velocity range in both systems and also spatially (in both sightlines). This is a remarkable uniformity not seen in Lyman limit systems. The uniformity of the cloud properties suggests that the multiple clouds are not part of a "halo". Based upon photoionization modeling, we constrain the ionization parameters in the range -6.2 < log(U) < -5.1, where the range b...

  11. The ESO UVES Advanced Data Products Quasar Sample-V. Identifying the Galaxy Counterpart to the sub-Damped Ly-alpha System towards Q2239-2949

    CERN Document Server

    Zafar, Tayyaba; Péroux, Céline; Quiret, Samuel; Fynbo, Johan P U; Ledoux, Cédric; Deharveng, Jean-Michel

    2016-01-01

    Gas flows in and out of galaxies are one of the key unknowns in todays' galaxy evolution studies. Because gas flows carry mass, energy and metals, they are believed to be closely connected to the star formation history of galaxies. Most of these processes take place in the circum-galactic medium (CGM) which remains challenging to observe in emission. A powerful tool to study the CGM gas is offered by combining observations of the gas traced by absorption lines in quasar spectra with detection of the stellar component of the same absorbing-galaxy. To this end, we have targeted the zabs=1.825 sub-Damped Ly-alpha absorber (sub-DLA) towards the zem=2.102 quasar 2dF J 223941.8-294955 (hereafter Q2239-2949) with the ESO VLT/X-Shooter spectrograph. Our aim is to investigate the relation between its properties in emission and in absorption. The derived metallicity of the sub-DLA with log N(HI) = 19.84+/-0.14 cm-2 is [M/H] >-0.75. Using the Voigt profile optical depth method, we measure Delta_v90(FeII)=64 kms-1. The s...

  12. Directly imaging damped Ly-alpha galaxies at z>2. III: The star formation rates of neutral gas reservoirs at z~2.7

    CERN Document Server

    Fumagalli, Michele; Prochaska, J Xavier; Rafelski, Marc; Kanekar, Nissim

    2014-01-01

    We present results from a survey designed to probe the star formation properties of 32 damped Ly-alpha systems (DLAs) at z~2.7. By using the "double-DLA" technique that eliminates the glare of the bright background quasars, we directly measure the rest-frame FUV flux from DLAs and their neighbouring galaxies. We place stringent constraints on the star formation rates (SFRs) of DLAs to 2-sigma limits of 2 M/yr at impact parameters b < SFR^(0.8)+6 kpc, in contrast with current samples of confirmed DLA galaxies, which appear to be biased. Our observations also disfavor a scenario in which the majority of DLAs arise from bright LBGs at distances 20 < b < 100 kpc. These new findings corroborate a picture in which DLAs do not originate from highly star forming systems that are coincident with the absorbers, and instead suggest that DLAs are associated with faint, possibly isolated, star-forming galaxies. Potential shortcomings of this scenario and future strategies for further investigation are discussed.

  13. Herschel FIR counterparts of selected Ly-alpha emitters at z~2.2. Fast evolution since z~3 or missed obscured AGNs?

    CERN Document Server

    Bongiovanni, A; Cepa, J; Garcia, A M Perez; Sanchez-Portal, M; Ederoclite, A; Aguerri, J A L; Alfaro, E J; Altieri, B; Andreani, P; Aparicio-Villegas, M T; Aussel, H; Benitez, N; Berta, S; Broadhurst, T; Cabrera-Cano, J; Castander, F J; Cava, A; Cervino, M; Chulani, H; Cimatti, A; Cristobal-Hornillos, D; Daddi, E; Dominguez, H; Elbaz, D; Fernandez-Soto, A; Schreiber, N Forster; Genzel, R; Gomez, M F; Delgado, R M Gonzalez; Grazian, A; Gruppioni, C; Herreros, J M; Iglesias-Groth, S; Infante, L; Lutz, D; Magnelli, B; Magdis, G; Maiolino, R; Marquez, I; Martinez, V J; Masegosa, J; Moles, M; Molino, A; Nordon, R; del Olmo, A; Perea, J; Poglitsch, A; Popesso, P; Pozzi, F; Prada, F; Quintana, J M; Riguccini, L; Rodighiero, G; Saintonge, A; Sanchez, S F; Santini, P; Shao, L; Sturm, E; Tacconi, L; Valtchanov, I

    2010-01-01

    Ly-alpha emitters (LAEs) are seen everywhere in the redshift domain from local to z~7. Far-infrared (FIR) counterparts of LAEs at different epochs could provide direct clues on dust content, extinction, and spectral energy distribution (SED) for these galaxies. We search for FIR counterparts of LAEs that are optically detected in the GOODS-North field at redshift z~2.2 using data from the Herschel Space Telescope with the Photodetector Array Camera and Spectrometer (PACS). The LAE candidates were isolated via color-magnitude diagram using the medium-band photometry from the ALHAMBRA Survey, ancillary data on GOODS-North, and stellar population models. According to the fitting of these spectral synthesis models and FIR/optical diagnostics, most of them seem to be obscured galaxies whose spectra are AGN-dominated. From the analysis of the optical data, we have observed a fraction of AGN or composite over source total number of ~0.75 in the LAE population at z~2.2, which is marginally consistent with the fractio...

  14. Directly Imaging Damped Ly-Alpha Galaxies at Redshifts Greater Than 2. III: The Star Formation Rates of Neutral Gas Reservoirs at Redshifts of Approximately 2.7

    Science.gov (United States)

    Fumagalli, Michele; OMeara, John M.; Prochaska, J. Xavier; Rafelski, Marc; Kanekar, Nissim

    2014-01-01

    We present results from a survey designed to probe the star formation properties of 32 damped Ly alpha systems (DLAs) at redshifts of approximately 2.7. By using the "double-DLA" technique that eliminates the glare of the bright background quasars, we directly measure the rest-frame FUV flux from DLAs and their neighbouring galaxies. At the position of the absorbing gas, we place stringent constraints on the unobscured star formation rates (SFRs) of DLAs to 2 sigma limits of psi less than 0.09-0.27 solar mass yr(exp -1), corresponding to SFR surface densities sigma(sub sfr) less than 10(exp -2.6)-10(exp -1.5) solar mass yr(exp -1) kpc(exp -2). The implications of these limits for the star formation law, metal enrichment, and cooling rates of DLAs are examined. By studying the distribution of impact parameters as a function of SFRs for all the galaxies detected around these DLAs, we place new direct constraints on the bright end of the UV luminosity function of DLA hosts. We find that less than or equal to 13% of the hosts have psi greater than or equal to 2 solar mass yr(exp -1) at impact parameters b(sub dla) less than or equal to (psi/solar mass yr(exp -1))(exp 0.8) + 6 kpc, differently from current samples of confirmed DLA galaxies. Our observations also disfavor a scenario in which the majority of DLAs arise from bright LBGs at distances 20 less than or equal to b(sub dla) less than 100 kpc. These new findings corroborate a picture in which DLAs do not originate from highly star forming systems that are coincident with the absorbers, and instead suggest that DLAs are associated with faint, possibly isolated, star-forming galaxies. Potential shortcomings of this scenario and future strategies for further investigation are discussed.

  15. A METAL-STRONG AND DUST-RICH DAMPED Ly{alpha} ABSORPTION SYSTEM TOWARD THE QUASAR SDSS J115705.52+615521.7

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jianguo [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming, Yunnan 650011 (China); Zhou Hongyan; Jiang Peng; Lu Honglin; Wang Huiyuan; Wang Tinggui [Key Laboratory for Research in Galaxies and Cosmology, Department for Astronomy, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China); Ge Jian; Hamann, Fred [Astronomy Department, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States); Xavier Prochaska, J. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Yuan Weimin, E-mail: wangjg@ynao.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2012-11-20

    We report the discovery of an unusual, extremely dust-rich and metal-strong damped Ly{alpha} absorption system (DLA) at a redshift z{sub a} = 2.4596 toward the quasar SDSS J115705.52+615521.7 with an emission-line redshift z{sub e} = 2.5125. The quasar spectrum, taken in the Sloan Digital Sky Survey, shows a very red color and a number of metal absorption lines, including C II, Al II, Si II, Fe II, and Zn II, which are confirmed and further characterized by follow-up spectroscopy made with the Multiple Mirror Telescope. Its neutral hydrogen column density N {sub HI} = 10{sup 21.8{+-}0.2} cm{sup -2} is among the highest values measured in quasar DLAs. The measured metal column density is N {sub ZnII} Almost-Equal-To 10{sup 13.8} cm{sup -2}, which is about 1.5 times larger than the largest value in any previously observed quasar DLAs. We derive the extinction curve of the dusty DLA using a new technique, which is an analog of the 'pair method' widely used to measure extinction curves in the Milky Way (MW). The best-fit curve is an MW-like law with a significant broad feature centered around 2175 A in the rest frame of the absorber. The measured extinction A{sub V} Almost-Equal-To 0.92 mag is unprecedentedly high in quasar DLAs. After applying an extinction correction, the i-band absolute magnitude of the quasar is as high as M{sub i} Almost-Equal-To -29.4 mag, placing it as one of the most luminous quasars ever known. The large gas-phase relative abundance of [Zn/Fe] Almost-Equal-To 1.0 indicates that metals are heavily depleted onto dust grains in the absorber. The dust depletion level is between that of the warm and cool clouds in the MW. This discovery is suggestive of the existence of a rare yet important population of dust-rich DLAs with both high metallicities and high column densities, which may have significant impact on the measurement of the cosmic evolution of neutral gas mass density and metallicity.

  16. The Lyman-alpha forest of a Lyman Break Galaxy VLT Spectra of MS1512-cB58 at z=2.724

    CERN Document Server

    Savaglio, S; Padovani, P

    2001-01-01

    The high redshift galaxy MS1512-cB58 (z=2.724, m_V=20.64) has been observed with the very efficient high resolution echelle spectrograph VLT/UVES. Although this is a very challenging observational program for a Southern hemisphere telescope (the galaxy is located at +36 deg declination), high resolution spectra (FWHM ~ 26 km/s) have revealed, with unprecedented detail along a galaxy sight line, the Lyman-alpha forest due to intervening clouds in the intergalactic medium (IGM). The mean depression D_A due to IGM absorption blueward of the galaxy Ly-alpha wavelength and the number density dn/dz of Ly-alpha clouds have been compared with equivalent results obtained for QSO sight lines at similar redshifts. Our results indicate a possible excess of absorption close to the galaxy. The mean depression at ~ 150 h_65^-1 Mpc comoving (Omega_m=0.3, Omega_Lambda=0.7) from the galaxy is D_A=0.36+/-0.03, to be compared with 0.22+/-0.04, expected from a best fit to QSO sight lines. In the same region (z=2.610), the number ...

  17. The Gunn-Peterson effect and the Lyman $\\alpha$ forest

    CERN Document Server

    Levshakov, S A

    1997-01-01

    We show that spatial correlations in a stochastic large scale velocity field in an otherwise smooth intergalactic medium (homogeneous comoving density) superposed on the general Hubble flow, may cause a `line-like' structure in QSO spectra similar to the population of unsaturated Ly-alpha forest lines which usually are attributed to individual clouds with 10^{11} <= N(HI) <= 5*10^{13} cm^{-2}. Therefore there is no clear observational distinction between a diffuse intergalactic medium and discrete intergalactic clouds. It follows that the HI-density in the diffuse intergalactic medium might be substantially underestimated if it is determined from the observed intensity distribution near the apparent continuum in high resolution spectra of QSOs. Our tentative estimate implies a diffuse neutral hydrogen opacity tau_{GP} = 0.3 at z = 3 and a current baryon density Omega_{IGM} = 0.08$, assuming a Hubble constant H = 70 km s^{-1} Mpc^{-1}.

  18. The QSO evolution derived from the HBQS and other complete QSO surveys

    CERN Document Server

    La Franca, F; Franca, Fabio La; Cristiani, Stefano

    1997-01-01

    An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3QSO surface density turns out to be a factor 2.2 higher than what measured by the PG survey, corresponding to a surface density of 0.013+/-.006 deg^{-2}. If the Edinburgh QSO Survey is included, an overdensity of a factor 2.7 is observed, corresponding to a density of 0.016+/-0.005 deg^{-2}. In order to derive the QSO optical luminosity function (LF) we used Monte Carlo simulations that take into account of the selection criteria, photometric errors and QSO spectral slope distribution. The LF can be represented with a Pure Luminosity Evolution (L(z)\\propto(1+z)^k) of a two power law both for q_0=0.5 and q_0=0.1. For q_0=0.5 k=3.26, slower than the previous Boyle's (1992) estimations of k=3.45. A flatter slope beta=-3.72 of the bright part of the LF is also required. The observed overdensity of bright QSOs ...

  19. The QSO evolution derived from the HBQS and other complete QSO surveys

    CERN Document Server

    La Franca, Fabio

    2016-01-01

    An ESO Key programme dedicated to an Homogeneous Bright QSO Survey (HBQS) has been completed. 327 QSOs (Mb<-23, 0.3QSO surface density turns out to be a factor 2.2 higher than what measured by the PG survey, corresponding to a surface density of 0.013+/-.006 deg^{-2}. If the Edinburgh QSO Survey is included, an overdensity of a factor 2.7 is observed, corresponding to a density of 0.016+/-0.005 deg^{-2}. In order to derive the QSO optical luminosity function (LF) we used Monte Carlo simulations that take into account of the selection criteria, photometric errors and QSO spectral slope distribution. The LF can be represented with a Pure Luminosity Evolution (L(z)\\propto(1+z)^k) of a two power law both for q_0=0.5 and q_0=0.1. For q_0=0.5 k=3.26, slower than the previous Boyle's (1992) estimations of k=3.45. A flatter slope beta=-3.72 of the bright part of the LF is also required. The observed overdensity of bright QSOs ...

  20. HST/COS Spectra of DF Tau and V4046 SGR: First Detection of Molecular Hydrogen Absorption Against the Ly$\\alpha$ Emission Line

    CERN Document Server

    Yang, Hao; France, Kevin

    2011-01-01

    We report the first detection of molecular hydrogen (H$_{2}$) absorption in the Lyman-$\\alpha$ emission line profiles of two classical T Tauri stars (CTTSs), DF Tau and V4046 Sgr, observed by \\emph{HST}/COS. This absorption is the energy source for many of the Lyman-band H$_{2}$ fluorescent lines commonly seen in the far-ultraviolet spectra of CTTSs. We find that the absorbed energy in the H$_{2}$ pumping transitions from a portion of the Lyman-$\\alpha$ line significantly differ from the amount of energy in the resulting fluorescent emission. By assuming additional absorption in the H I Lyman-$\\alpha$ profile along our light of sight, we can correct the H$_{2}$ absorption/emission ratios so that they are close to unity. The required H I absorption for DF Tau is at a velocity close to the radial velocity of the star, consistent with H I absorption in the edge-on disk and interstellar medium. For V4046 Sgr, a nearly face-on system, the required absorption is between +100 km/s and +290 km/s, most likely resultin...

  1. The 2dF-SDSS LRG and QSO Survey: The spectroscopic QSO catalogue

    CERN Document Server

    Croom, Scott M; Shanks, Tom; Boyle, Brian J; Sharp, Robert G; Bland-Hawthorn, Joss; Bridges, Terry; Brunner, Robert J; Cannon, Russell; Carson, Daniel; Chiu, Kuenley; Colless, Matthew; Couch, Warrick; De Propris, Roberto; Drinkwater, Michael J; Edge, Alastair; Fine, Stephen; Loveday, Jon; Miller, Lance; Myers, Adam D; Nichol, Robert C; Outram, Phil; Pimbblet, Kevin; Roseboom, Isaac; Ross, Nicholas; Schneider, Donald P; Smith, Allyn; Stoughton, Chris; Strauss, Michael A; Wake, David

    2008-01-01

    We present the final spectroscopic QSO catalogue from the 2dF-SDSS LRG and QSO (2SLAQ) Survey. This is a deep, 18QSO sample (including objects previously observed in the SDSS and 2QZ surveys) contains 12702 QSOs. The new 2SLAQ spectroscopic data set also contains 2343 Galactic stars, including 362 white dwarfs, and 2924 narrow emission line galaxies with a median redshift of z=0.22. We present detailed completeness estimates for the survey, based on modelling of QSO colours, including host galaxy contributi...

  2. WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope

    Science.gov (United States)

    Pieri, M. M.; Bonoli, S.; Chaves-Montero, J.; Pâris, I.; Fumagalli, M.; Bolton, J. S.; Viel, M.; Noterdaeme, P.; Miralda-Escudé, J.; Busca, N. G.; Rahmani, H.; Peroux, C.; Font-Ribera, A.; Trager, S. C.

    2016-12-01

    In these proceedings we describe the WEAVE-QSO survey, which will observe around 400,000 high redshift quasars starting in 2018. This survey is part of a broader WEAVE survey to be conducted at the 4.2m William Herschel Telescope. We will focus on chiefly on the science goals, but will also briefly summarise the target selection methods anticipated and the expected survey plan. Understanding the apparent acceleration in the expansion of the Universe is one of the key scientific challenges of our time. Many experiments have been proposed to study this expansion, using a variety of techniques. Here we describe a survey that can measure this acceleration and therefore help elucidate the nature of dark energy: a survey of the Lyα forest (and quasar absorption in general) in spectra towards z>2 quasars (QSOs). Further constraints on neutrino masses and warm dark matter are also anticipated. The same data will also shed light on galaxy formation via study of the properties of inflowing/outflowing gas associated with nearby galaxies and in a cosmic web context. Gas properties are sensitive to density, temperature, UV radiation, metallicity and abundance pattern, and so constraint galaxy formation in a variety of ways. WEAVE-QSO will study absorbers with a dynamic range spanning more than 8 orders of magnitude in column density, their thermal broadening, and a host of elements and ionization species. A core principal of the WEAVE-QSO survey is the targeting of QSOs with near 100% efficiency principally through use of the J-PAS (r < 23.2) and Gaia (r ≲ 20) data.

  3. The HI Content and Extent of Low Surface Brightness Galaxies - Could LSB Galaxies be Responsible for Damped Ly-alpha Absorption?

    CERN Document Server

    O'Neil, K

    2001-01-01

    Low surface brightness galaxies, those galaxies with a central surface brightness at least one magnitude fainter than the night sky, are often not included in discussions of extragalactic gas at z < 0.1. In this paper we review many of the properties of low surface brightness galaxies, including recent studies which indicate low surface brightness systems may contribute far more to the local HI luminosity function than previously thought. Additionally, we use the known (HI) gas properties of low surface brightness galaxies to consider their possible contribution to nearby damped Lyman-alpha absorbers.

  4. Radiance line ratios Ly-β/Ly-α, Ly-γ/Ly-α, Ly-δ/Ly-α, and Ly-ε/Ly-α for soft X-ray emissions following charge exchange between C{sup 6+} and Kr

    Energy Technology Data Exchange (ETDEWEB)

    Andrianarijaona, V.M. [Department of Physics, Pacific Union College, Angwin, CA 94508 (United States); Wulf, D.; McCammon, D. [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Seely, D.G. [Department of Physics, Albion College, Albion, MI 49224 (United States); Havener, C.C. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6372 (United States)

    2015-05-01

    The radiance line ratios Ly-β/Ly-α, Ly-γ/Ly-α, Ly-δ/Ly-α, and Ly-ε/Ly-α for soft X-ray emission following charge exchange (CX) between C{sup 6+} and Kr are reported for collision energies between approximately 320 and 46,000 eV/u. The corresponding collision velocities (250–3000 km/s) are characteristic of the solar wind. X-ray spectra were obtained at the Oak Ridge National Laboratory Multicharged Ion Research Facility using a microcalorimeter X-ray detector with a resolution on the order of 10 eV FWHM. The measured Ly-ε/Ly-α is zero for all considered energies and suggests that very little, if any, capture to 6p occurs. The measured Ly-β/Ly-α and Ly-γ/Ly-α ratios intersect and form a well resolved node around (950 ± 50) km/s, which could be used as an astrophysical velocity indicative tool. The results reported here are compared to calculations for C{sup 6+} + H since no published theory for C{sup 6+} + Kr is known to exist. Double-electron-capture (DEC) and other multi-electron processes are possible. True double capture is estimated to be only 10% of the single-electron-capture (SEC)

  5. Providing stringent star formation rate limits of z$\\sim$2 QSO host galaxies at high angular resolution

    CERN Document Server

    Vayner, Andrey; Do, Tuan; Larkin, James E; Armus, Lee; Gallagher, Sarah C

    2014-01-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z=2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini-North Observatories using OSIRIS and NIFS coupled with the LGS-AO systems. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z=2.15. We demonstrate that the combination of AO and IFS provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a PSF from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy. We detect H$\\alpha$ and [NII] for two sources, SDSS J1029+6510 and SDSS J0925+06 that have both star formation and extended narrow-line emission. Assuming that the majority of narrow-line H$\\alpha$ is from star formation, we inf...

  6. Cosmological test with the QSO Hubble diagram

    CERN Document Server

    Lopez-Corredoira, M; Lusso, E; Risaliti, G

    2016-01-01

    A Hubble diagram (HD) has recently been constructed in the redshift range 099% C.L. The Quasi-Steady State Model is excluded at >95% C.L. The remaining four models (Lambda-CDM/wCDM, the R_h=ct Universe, the Friedmann open universe and a Static universe with a linear Hubble law) all pass the test. However, only Lambda-CDM/wCDM and $R_{\\rm h}=ct$ also pass the Alcock-Paczynski (AP) test. The optimized parameters in Lambda-CDM/wCDM are Omega_m=0.20^{+0.24}_{-0.20} and w_{de}=-1.2^{+1.6}_{-infinity} (the dark-energy equation-of-state). Combined with the AP test, these values become Omega_m=0.38^{+0.20}_{-0.19} and w_{de}=-0.28^{+0.52}_{-0.40}. But whereas this optimization of parameters in Lambda-CDM/wCDM creates some tension with their concordance values, the $R_{\\rm h}=ct$ Universe has the advantage of fitting the QSO and AP data without any free parameters.

  7. A New Population of High-z, Dusty Lyman-alpha Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

    Science.gov (United States)

    Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger, L.; Jarrett, Tom; Lonsdale, Carol; hide

    2013-01-01

    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 approx. 10(exp 13)-10(exp 14) Solar L) and have warm colors. They are typically more luminous and warmer than other dusty, z approx.. 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Ly-alpha, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy.

  8. Terminal Velocity Infall in QSO Absorption Line Halos

    Science.gov (United States)

    Benjamin, Robert A.

    We explore the hypothesis that clouds detected in quasar absorption line systems are falling at a terminal velocity toward the center of high redshift gaseous galactic halos. Since both the ionization level and terminal velocity of halo clouds increase with increasing distance from the central galaxy, velocity resolved profiles of highly ionized gas are predicted to have a greater width than low ionization gas. A line of sight passing through the center of gaseous halo (an idealized damped Ly alpha system), yields low ionization absorption at the velocity of the galaxy, flanked by high ionization on either side. Reasonable halo parameters yield total velocity extents for C IV of Delta v_{C IV}=100-200 km s^{-1}, in agreement with many systems observed by Lu et al (1997). The remaining systems may better described by the rotating disk model of Prochaska & Wolfe (1998). Finally, observational tests are suggested for verifying or falsifying the terminal velocity hypothesis for these systems.

  9. The LyA-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization

    CERN Document Server

    Dijkstra, Mark

    2016-01-01

    The escape of ionizing Lyman Continuum (LyC) photons requires the existence of low-N_HI sightlines, which also promote escape of Lyman-Alpha (Lya). We use a suite of 2500 Lya Monte-Carlo radiative transfer simulations through models of dusty, clumpy interstellar (`multiphase') media from Gronke & Dijkstra (2016), and compare the escape fractions of Lya [f_esc(Lya)] and LyC radiation [f_esc(LyC)]. We find that f_esc(LyC) and f_esc(Lya) are correlated: galaxies with a low f_esc(Lya) consistently have a low f_esc(LyC), while galaxies with a high f_esc(Lya) exhibit a large dispersion in f_esc(LyC). We argue that there is increasing observational evidence that Lya escapes more easily from UV-faint galaxies. The correlation between f_esc(LyC) and f_esc(Lya) then implies that UV-faint galaxies contribute more to the ionizing background than implied by the faint-end slope of the UV-luminosity function. In multiphase gases, the ionizing escape fraction is most strongly affected by the cloud covering factor, f_cl, ...

  10. The Deuterium to Hydrogen Abundance Ratio Towards the QSO SDSS1558-0031

    CERN Document Server

    O'Meara, J M; Prochaska, J X; Prochter, G E; Bernstein, R A; Burgess, K M; Meara, John M. O'; Burles, Scott; Prochaska, Jason X.; Prochter, Gabe E.; Bernstein, Rebecca A.; Burgess, Kristin M.

    2006-01-01

    We present a measurement of the D/H abundance ratio in a metal-poor damped Lyman alpha (DLA) system along the sightline of QSO SDSS1558-0031. The DLA system is at redshift z = 2.70262, has a neutral column density of log(NHI)=20.67+/-0.05 cm^2, and a gas-phase metallicity [O/H]= -1.49 which indicates that deuterium astration is negligible. Deuterium absorption is observed in multiple Lyman series with a column density of log(NDI)=16.19+/-0.04 cm^2, best constrained by the deuterium Lyman-11 line. We measure log(D/H) = -4.48+/-0.06, which when combined with previous measurements along QSO sightlines gives a best estimate of log(D/H) = -4.55+/-0.04, where the 1-sigma error estimate comes from a jackknife analysis of the weighted means. Using the framework of standard big bang nucleosynthesis, this value of D/H translates into a baryon density of Omega_b h^2 = 0.0213 +/- 0.0013 +/- 0.0004 where the error terms represent the 1-sigma errors from D/H and the uncertainties in the nuclear reaction rates respectively....

  11. Studying Lyman-alpha escape and reionization in Green Pea galaxies

    Science.gov (United States)

    Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Gronke, Max; Leitherer, Claus; Wofford, Aida; Dijkstra, Mark

    2017-01-01

    Green Pea galaxies are low-redshift galaxies with extreme [OIII]5007 emission line. We built the first statistical sample of Green Peas observed by HST/COS and used them as analogs of high-z Lyman-alpha emitters to study Ly-alpha escape and Ly-alpha sizes. Using the HST/COS 2D spectra, we found that Ly-alpha sizes of Green Peas are larger than the UV continuum sizes. We found many correlations between Ly-alpha escape fraction and galactic properties -- dust extinction, Ly-alpha kinematic features, [OIII]/[OII] ratio, and gas outflow velocities. We fit an empirical relation to predict Ly-alpha escape fraction from dust extinction and Ly-alpha red-peak velocity. In the JWST era, we can use this relation to derive the IGM HI column density along the line of sight of each high-z Ly-alpha emitter and probe the reionization process.

  12. Gemini imaging of QSO host galaxies at z~2

    CERN Document Server

    Croom, S; Boyle, B; Shanks, T; Miller, L; Smith, R; Croom, Scott; Schade, David; Boyle, Brian; Shanks, Tom; Miller, Lance; Smith, Robert

    2004-01-01

    We present results of a Gemini adaptive optics (AO) imaging program to investigate the host galaxies of typical QSOs at z~2. Our aim is to study the host galaxies of typical, L*_qso QSOs at the epoch of peak QSO and star formation activity. The large database of faint QSOs provided by the 2dF QSO Redshift Survey allows us to select a sample of QSOs at z=1.75-2.5 which have nearby (<12 arcsecond separation) bright stars suitable for use as AO guide stars. We have observed a sample of 9 QSOs. The images of these sources have AO corrected full-width at half-maximum of between 0.11 and 0.25 arcseconds. We use multiple observations of point spread function (PSF) calibration star pairs in order to quantify any uncertainty in the PSF. We then factored these uncertainties into our modelling of the QSO plus host galaxy. In only one case did we convincingly detect a host (2QZ J133311.4+001949, at z=1.93). This host galaxy has K=18.5+-0.2 mag with a half-light radius, r_e=0.55+-0.1'', equivalent to ~3L*_gal assuming ...

  13. A New NIR Flareof the QSO PMNJ2301-0157

    Science.gov (United States)

    Carrasco, L.; Miramon, J.; Recillas, E.; Porras, A.; Chavushyan, V.; Mayya, D. Y.

    2016-12-01

    We report on the new NIR flare of the high redshift QSO PMNJ2301-0157 (z=0.778), cross identified with the source BZQJ 2301-1058. On November 13th,2016 (MJD 2457705.722), we found the source with the following flux in the NIR band: H = 14.287 +/- 0.03.

  14. A Uniform Analysis of the Lyα Forest at z=0-5. II. Measuring the Mean Intensity of the Extragalactic Ionizing Background Using the Proximity Effect

    Science.gov (United States)

    Scott, Jennifer; Bechtold, Jill; Dobrzycki, Adam; Kulkarni, Varsha P.

    2000-09-01

    Moderate-resolution data for 40 quasi-stellar objects (QSOs) at z~2 were combined with spectra of comparable resolution of 59 QSOs with redshifts greater than 1.7 found in the literature to form a large, homogeneous sample of moderate-resolution (~1 Å) QSO spectra. These spectra were presented and the statistics of the Lyα forest were discussed in Paper I. In this analysis, we demonstrate that a proximity effect is present in the data; i.e., there exists a significant (5.5 σ) deficit of lines at zabs~zem. Within 1.5 h-1 Mpc of the QSO emission redshift, the significance does depend on QSO luminosity, in accordance with the theory that this effect is caused by enhanced ionization of hydrogen in the vicinity of the QSO from UV photons from the QSO itself. The photoionization model of Bajtlik, Duncan, & Ostriker permits an estimate of the mean intensity of the extragalactic background radiation at the Lyman limit. We compare the results of this standard analysis with those obtained using a maximum likelihood technique. If the spectrum of the background is assumed to be identical to that of each individual QSO, and if this background is assumed to be constant over the redshift range 1.7QSO redshifts based on the Lyα emission line. Systemic QSO redshifts based on the [O III] λ5007 emission line for 19 objects in our sample show an average redshift of ~400 km s-1 with respect to Lyα emission. Using redshifts based on [O III] or Mg II for the 35 objects for which they are measured and adding 400 km s-1 to the remaining QSO Lyα redshifts gives a lower value of J(ν0), 7.0+3.4-4.4×10-22 ergs s-1 cm-2 Hz-1 sr-1. This value is in reasonable agreement with the predictions of various models of the ionizing background based on the integrated quasar luminosity function. Allowing for the fact that individual QSOs have different spectral indices that may also be

  15. The Lyman alpha reference sample

    DEFF Research Database (Denmark)

    Hayes, M.; Östlin, G.; Schaerer, D.

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 Lyα, Hα, and the ......We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028

  16. A computational method to help identify and measure metal lines in high resolution QSO spectra

    Institute of Scientific and Technical Information of China (English)

    Xi-Heng Shi; David Tytler; Jin-Liang Hou; David Kirkman; Jeffery Lee; Benjamin Ou

    2011-01-01

    A computational code is developed to help identify metal absorption lines in high resolution QSO spectra,especially in the Lyα forest.The input to the code includes a list of line central wavelengths,column densities and Doppler widths.The code then searches for candidate metal absorption systems and assesses the probability that each system could be real.The framework of the strategy we employ is described in detail and we discuss how to estimate the errors in line profile fitting that are essential to identification.A series of artificial spectra is constructed to calibrate the performance of the code.Due to the effects of blending and noise on Voigt profile fitting,the completeness of the identification depends on the column density of absorbers.For intermediate and strong artificial metal absorbers,more than 90% could be confirmed by the code.The results of applying the code to the real spectra of QSOs HS0757+5218 and Q0100+1300 are also presented.

  17. Constraints on QSO models from a relation between the QSO luminosity function and the local black hole mass function

    CERN Document Server

    Yu, Q; Yu, Qingjuan; Lu, Youjun

    2004-01-01

    QSOs are believed to be powered by accretion onto massive black holes (BHs). In this paper, with assuming that each central BH in nearby galaxies has experienced the QSO phase and ignoring BH mergers, we establish a relation between the QSO luminosity function (LF) and the local BH mass function (MF). The QSOLF is jointly controlled by the luminosity evolution of individual QSOs and the triggering history of the accretion onto seed BHs. By comparing the time integral of the QSOLF with that inferred from local BHs, we separate the effect of the luminosity evolution of individual QSOs from the effect of the triggering history. With assuming that the nuclear luminosity evolution includes two phases (first increasing at the Eddington luminosity with growth of BHs and then declining), we find that observations are generally consistent with the expected relation between the QSOLF and the local BHMF, and obtain the constraints on QSO models and BH growth. We point out that the value of the QSO lifetime is hard to be...

  18. Lyman-alpha radiation hydrodynamics of galactic winds before cosmic reionization

    CERN Document Server

    Smith, Aaron; Loeb, Abraham

    2016-01-01

    The dynamical impact of Lyman-alpha (Ly{\\alpha}) radiation pressure on galaxy formation depends on the rate and duration of momentum transfer between Ly{\\alpha} photons and neutral hydrogen gas. Although photon trapping has the potential to multiply the effective force, ionizing radiation from stellar sources may relieve the Ly{\\alpha} pressure before appreciably affecting the kinematics of the host galaxy or efficiently coupling Ly{\\alpha} photons to the outflow. We present self-consistent Ly{\\alpha} radiation-hydrodynamics simulations of high-$z$ galaxy environments by coupling the Cosmic Ly{\\alpha} Transfer code (COLT) with spherically symmetric Lagrangian frame hydrodynamics. The accurate but computationally expensive Monte-Carlo radiative transfer calculations are feasible under the one-dimensional approximation. In certain cases Ly{\\alpha} feedback significantly enhances the velocity of the shell of gas expanding around a central source. Radiative feedback alone is capable of ejecting baryons into the i...

  19. QSO Selection Algorithm Using Time Variability and Machine Learning: Selection of 1,620 QSO Candidates from MACHO LMC Database

    CERN Document Server

    Kim, Dae-Won; Byun, Yong-Ik; Alcock, Charles; Khardon, Roni

    2011-01-01

    We present a new QSO selection algorithm using a Support Vector Machine (SVM), a supervised classification method, on a set of extracted times series features including period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars and microlensing events using 58 known QSOs, 1,629 variable stars and 4,288 non-variables using the MAssive Compact Halo Object (MACHO) database as a training set. To estimate the efficiency and the accuracy of the model, we perform a cross-validation test using the training set. The test shows that the model correctly identifies ~80% of known QSOs with a 25% false positive rate. The majority of the false positives are Be stars. We applied the trained model to the MACHO Large Magellanic Cloud (LMC) dataset, which consists of 40 million lightcurves, and found 1,620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false po...

  20. The First Systematic Survey for Lyman Alpha Emitters at z=7.3 with Red-sensitive Subaru/Suprime-Cam

    CERN Document Server

    Shibuya, Takatoshi; Ota, Kazuaki; Iye, Masanori; Ouchi, Masami; Furusawa, Hisanori; Shimasaku, Kazuhiro; Hattori, Takashi

    2011-01-01

    We have performed deep imaging surveys for Lyman Alpha emitters (LAEs) at redshift ~ 7.3 in two blank fields, the Subaru Deep Field (SDF) and the Subaru/XMM-Newton Deep Field (SXDF), using the Subaru/Suprime-Cam equipped with new red-sensitive CCDs and a new narrow-band filter, NB1006 (lambda_c=10,052A, FWHM=214A). By comparing the NB1006 magnitudes of detected objects with those at other shorter wavelength bands, we identified four objects as LAE candidates that exhibit luminosity excess in NB1006. By carrying out deep follow-up spectroscopy for three of them using Subaru/FOCAS and Keck/DEIMOS, a definitively asymmetric emission line is detected for one of them, SXDF-NB1006-2. Assuming this line is LyA, this object is a LAE at z=7.215 which has luminosity of 1.2^{+1.5}_{-0.6} x 10^{43} erg s-1, star formation rate (SFR) of 11 Mo yr-1 estimated from the LyA emission line, and a weighted skewness S_w = 4.90+-0.86. Another object, SDF-NB1006-2, shows variable photometry and is thus probably a quasar (QSO) or an...

  1. Expected z>5 QSO number counts in large area deep near-infrared surveys

    CERN Document Server

    Fontanot, Fabio; Jester, Sebastian

    2007-01-01

    The QSO luminosity function at z>5 provides strong constraints on models of joint evolution of QSO and their hosts. However, these observations are challenging because the low space densities of these objects necessitate surveying of large areas, in order to obtain statistically meaningful samples, while at the same time cosmological redshifting and dimming means that rather deep Near Infrared (NIR) imaging must be carried out. Several upcoming and proposed facilities with wide-field NIR imaging capabilities will open up this new region of parameter space. In this paper we present predictions for the expected number counts of z>5 QSOs, based on simple empirical models of QSO evolution, as a function of redshift, depth and surveyed area. We compute the evolution of observed-frame QSO magnitudes and colors in a representative photometric system covering the wavelength range 550nm < \\lambda < 1800nm, and combine this information with different estimates for the evolution of the QSO luminosity function. We ...

  2. On a new method to analyse QSO spectra

    CERN Document Server

    Darriulat, Pierre

    2011-01-01

    A new method of analysis of QSO spectra, usually referred to as the "Thong method", has been recently presented and made use of in a number of publications. Several of these have been withdrawn because the authors have been convicted of plagiarism. However, there exists no publication showing that the method itself, which is an original contribution of the authors, is wrong. The purpose of the present note is to show that it is and that the results obtained when using it, including limits on the time variation of the fine structure constant many times smaller than published by other authors, must therefore be ignored and discarded.

  3. The 2dF-SDSS LRG and QSO Survey: the QSO luminosity function at 0.4

    CERN Document Server

    Croom, Scott M; Shanks, Tom; Boyle, Brian J; Strauss, Michael A; Myers, Adam D; Nichol, Robert C; Pimbblet, Kevin A; Ross, Nicholas P; Schneider, Donald P; Sharp, Robert G; Wake, David A

    2009-01-01

    We present the QSO luminosity function of the completed 2dF-SDSS LRG and QSO (2SLAQ) survey, based on QSOs photometrically selected from Sloan Digital Sky Survey imaging data and then observed spectroscopically using the 2dF instrument on the Anglo-Australian Telescope. We analyse 10637 QSOs in the redshift range 0.420.0, as found previously by Richards et al. (2005). The luminosity function is consistent with other previous, much smaller, samples produced to the depth of 2SLAQ. By combining the 2SLAQ and SDSS QSO samples we produce a QSO luminosity function with an unprecedented combination of precision and dynamic range. With this we are able to accurately constrain both the bright and faint ends of the QSO LF. While the overall trends seen in the evolution of the QSO LF appear similar to pure luminosity evolution, the data show very significant departures from such a model. Most notably we see clear evidence that the number density of faint QSOs peaks at lower redshift than bright QSOs : QSOs with Mg>-23 h...

  4. On the Formation of Molecular Clumps in QSO Outflows

    Science.gov (United States)

    Ferrara, A.; Scannapieco, E.

    2016-12-01

    We study the origin of the cold molecular clumps in quasar outflows, recently detected in CO and HCN emission. We first describe the physical properties of such radiation-driven outflows and show that a transition from a momentum- to an energy-driven flow must occur at a radial distance of R≈ 0.25 {kpc}. During this transition, the shell of swept-up material fragments due to Rayleigh-Taylor instabilities, but these clumps contain little mass and are likely to be rapidly ablated by the hot gas in which they are immersed. We then explore an alternative scenario in which clumps form from thermal instabilities at R≳ 1 {kpc}, possibly containing enough dust to catalyze molecule formation. We investigate this process with 3D two-fluid (gas+dust) numerical simulations of a kpc3 patch of the outflow, including atomic and dust cooling, thermal conduction, dust sputtering, and photoionization from the QSO radiation field. In all cases, dust grains are rapidly destroyed in ≈ {10}4 years; and while some cold clumps form at later times, they are present only as transient features, which disappear as cooling becomes more widespread. In fact, we only find a stable two-phase medium with dense clumps if we artificially enhance the QSO radiation field by a factor of 100. This result, together with the complete destruction of dust grains, renders the interpretation of molecular outflows a very challenging problem.

  5. The dust content of QSO hosts at high redshift

    CERN Document Server

    Calura, F; Vignali, C; Pozzi, F; Pipino, A; Matteucci, F

    2013-01-01

    Infrared observations of high-z quasar (QSO) hosts indicate the presence of large masses of dust in the early universe. When combined with other observables, such as neutral gas masses and star formation rates, the dust content of z~6 QSO hosts may help constraining their star formation history. We have collected a database of 58 sources from the literature discovered by various surveys and observed in the FIR. We have interpreted the available data by means of chemical evolution models for forming proto-spheroids, investigating the role of the major parameters regulating star formation and dust production. For a few systems, given the derived small dynamical masses, the observed dust content can be explained only assuming a top-heavy initial mass function, an enhanced star formation efficiency and an increased rate of dust accretion. However, the possibility that, for some systems, the dynamical mass has been underestimated cannot be excluded. If this were the case, the dust mass can be accounted for by stan...

  6. QSO Pairs across Active Galaxies: Evidence of Blueshifts?

    Indian Academy of Sciences (India)

    D. Basu

    2006-12-01

    Several QSO pairs have been reported and their redshifts determined, where the two objects in each pair are located across an active galaxy. The usually accepted explanation of such occurrences is that the pair is ejected from the parent galaxy. Currently interpreted redshifted spectra for both the QSOs imply that both the objects are receding from the observer. However, ejection can occur towards and away from the observer with equal probability. We argue that for a system with two QSOs lying across the parent galaxy, ejection should have occurred in opposite directions, whereby one object will be approaching us and the other will be receding from us. The former would exhibit a blueshifted spectrum. We analyse here a sample of four such pairs and show that the observed spectrum of one QSO in each pair can be interpreted as blueshifted. The other exhibits the usual redshifted spectrum. A scenario based on the ‘sling-shot’ mechanism of ejection is presented to explain the occurrences of the pairs in opposite sides of the active galaxies moving in opposite directions.

  7. Unobscured QSO2: A New Class of Objects?

    CERN Document Server

    Wolter, A; Henry, J P; Mullis, C R

    2005-01-01

    We present in this paper optical and X-ray follow up observations for three X-ray selected objects extracted from the ROSAT North Ecliptic Pole survey which is a flux-limited, completely identified survey. All three objects have X-ray luminosities in the 10^44 erg/s regime and show narrow emission lines in their optical discovery spectra, typical of QSO2 type objects. Spectroscopic data for the three QSO2 candidates, obtained with the Telescopio Nazionale Galileo, confirm the widths of the Halpha or Hbeta emission lines are less than 750 km/s. On the other hand XMM-Newton data do not show any sign of obscuration as expected for this class of objects. The X-ray spectra of the three objects are all well fit by a single power law model with Gamma~1.7 with low energy absorption fixed to the Galactic value along the line of sight to each object. Most observational evidence supports the scenario where optical and X-ray obscurations are linked, contrary to our findings. We discuss the unanticipated results of these ...

  8. Lyman alpha emission in starburst galaxies

    Science.gov (United States)

    Kunth, Daniel

    1999-07-01

    We propose to perform a deep study of Ly-alpha emission and destruction in 3 star-forming galaxies. These objects have been already observed with the GHRS and exhibit a variety of situations, with Ly-alpha showing P Cyg profiles, secondary emissions or even a deep damped absorption line with no emission. They also span a range of intrinsic properties: IZW18 is a gas-rich, metal deficient dust free dwarf galaxy, Haro 2 has a simple morphology while IRAS 08339+6517 is a luminous IRAS starburst galaxy with more dust and complex Ly- alpha profile. The use of STIS will allow for the first time to study the geometrical/kinematical configuration of the ionized and neutral gas across the galaxies nuclear regions and pin point the effects of porosity and the kinematical structure of the ISM, that may play the key roles {in addition to dust} in the detectability of the line. This study will have important impact for cosmology since Ly-alpha emitters are nowaday found at high-re dshift. We strongly emphasize that since Ly-alpha is primarely a diagnostic of the ISM, a full understanding of how the ISM and Ly-alpha are related is a necessary step before we can hope to correlate Ly-alpha to the cosmic star-formation rate. Our results will be interpreted against the model of superbubble evolution developed with G. Tenorio Tagle.

  9. WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope

    CERN Document Server

    Pieri, M M; Chaves-Montero, J; Paris, I; Fumagalli, M; Bolton, J S; Viel, M; Noterdaeme, P; Miralda-Escudé, J; Busca, N G; Rahmani, H; Peroux, C; Font-Ribera, A; Trager, S C

    2016-01-01

    In these proceedings we describe the WEAVE-QSO survey, which will observe around 400,000 high redshift quasars starting in 2018. This survey is part of a broader WEAVE survey to be conducted at the 4.2m William Herschel Telescope. We will focus on chiefly on the science goals, but will also briefly summarise the target selection methods anticipated and the expected survey plan. Understanding the apparent acceleration in the expansion of the Universe is one of the key scientific challenges of our time. Many experiments have been proposed to study this expansion, using a variety of techniques. Here we describe a survey that can measure this acceleration and therefore help elucidate the nature of dark energy: a survey of the Lyman-alpha forest (and quasar absorption in general) in spectra towards z>2 quasars (QSOs). Further constraints on neutrino masses and warm dark matter are also anticipated. The same data will also shed light on galaxy formation via study of the properties of inflowing/outflowing gas associ...

  10. Molecular hydrogen from z = 0.0963 DLA towards the QSO J1619+3342

    CERN Document Server

    Srianand, Raghunathan; Muzahid, Sowgat; Mohan, Vijay

    2014-01-01

    We report the detection of H2 in a zabs= 0.0963 Damped Lyman-{\\alpha} (DLA) system towards zem = 0.4716 QSO J1619+3342. This DLA has log N(H I) = 20.55 (0.10), 18.13 < log N(H2) < 18.40, [S/H] = -0.62 (0.13), [Fe/S] = -1.00 (0.17) and the molecular fraction -2.11 < log f(H2) < -1.85. The inferred gas kinetic temperature using the rotational level population is in the range 95 - 132 K. We do not detect C I or C II* absorption from this system. Using R- and V-band deep images we identify a sub-L* galaxy at an impact parameter of 14 kpc from the line of sight, having consistent photometric redshift, as a possible host for the absorber. We use the photoionization code CLOUDY to get the physical conditions in the H2 component using the observational constrains from H2, C I, C II* and Mg I. All the observations can be consistently explained if one or more of the following is true: (i) Carbon is underabundant by more than 0.6 dex as seen in halo stars with Z ~ 0.1 Z_sun, (ii) H I associated with H2 compo...

  11. Chandra ACIS-S Observations of Three Quasars with Low-Redshift Damped Ly-alpha Absorption Constraints on the Cosmic Neutral-Gas-Phase Metallicity at Redshift z \\approx 0.4

    CERN Document Server

    Turnshek, D A; Ptak, A F; Griffiths, R E; Monier, E M; Turnshek, David A.; Rao, Sandhya M.; Ptak, Andrew F.; Griffiths, Richard E.; Monier, Eric M.

    2003-01-01

    Chandra X-Ray Observatory (CXO) ACIS-S spectra of three quasars which lie behind three foreground damped Lyman alpha (DLA) absorbers are analyzed in order to attempt to determine the amount of photoelectric absorption due to metals present in their x-ray spectra. These absorbers are the three largest neutral hydrogen column density absorption-line systems known at low redshift (0.313 \\le z_abs \\le 0.524). They have HI column densities which lie between 3E21 and 5E21 atoms/cm^2. At these redshifts the amount of photoelectric absorption at x-ray energies is primarily an indicator of the oxygen abundance. Since the column densities of these systems are so high, one would expect accurate metallicity measurements of them to yield a robust estimate of the column-density-weighted cosmic neutral-gas-phase metallicity at z \\approx 0.4. We consider cases where the DLA gas has solar element abundance ratios and ones with the alpha-group element abundance ratios enhanced. For the adopted assumptions, the column-density-w...

  12. On the Diffuse Lyman-alpha Halo Around Lyman-alpha Emitting Galaxies

    CERN Document Server

    Lake, Ethan; Cen, Renyue; Sadoun, Raphael; Momose, Rieko; Ouchi, Masami

    2015-01-01

    Ly$\\alpha$ photons scattered by neutral hydrogen atoms in the circumgalactic media or produced in the halos of star-forming galaxies are expected to lead to extended Ly$\\alpha$ emission around galaxies. Such low surface brightness Ly$\\alpha$ halos (LAHs) have been detected by stacking Ly$\\alpha$ images of high-redshift star-forming galaxies. We study the origin of LAHs by performing radiative transfer modeling of nine $z=3.1$ Lyman-Alpha Emitters (LAEs) in a high resolution hydrodynamic galaxy formation simulation. We develop a method of computing the mean Ly$\\alpha$ surface brightness profile of each LAE by effectively integrating over many different observing directions. Without adjusting any parameters, our model yields an average Ly$\\alpha$ surface brightness profile in remarkable agreement with observations. We find that observed LAHs can not be accounted for solely by photons originating from the central LAE and scattered to large radii by hydrogen atoms in the circumgalactic gas. Instead, Ly$\\alpha$ em...

  13. TensorLy: Tensor Learning in Python

    NARCIS (Netherlands)

    Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

    2016-01-01

    Tensor methods are gaining increasing traction in machine learning. However, there are scant to no resources available to perform tensor learning and decomposition in Python. To answer this need we developed TensorLy. TensorLy is a state of the art general purpose library for tensor learning. Writte

  14. TensorLy: Tensor learning in Python

    NARCIS (Netherlands)

    Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

    2016-01-01

    Tensor methods are gaining increasing traction in machine learning. However, there are scant to no resources available to perform tensor learning and decomposition in Python. To answer this need we developed TensorLy. TensorLy is a state of the art general purpose library for tensor learning. Writt

  15. TensorLy: Tensor Learning in Python

    NARCIS (Netherlands)

    Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

    2016-01-01

    Tensor methods are gaining increasing traction in machine learning. However, there are scant to no resources available to perform tensor learning and decomposition in Python. To answer this need we developed TensorLy. TensorLy is a state of the art general purpose library for tensor learning.

  16. Large-scale opacity fluctuations in the Lyα forest: evidence for QSOs dominating the ionizing UV background at z ∼ 5.5-6?

    Science.gov (United States)

    Chardin, Jonathan; Puchwein, Ewald; Haehnelt, Martin G.

    2017-03-01

    Lyα forest data probing the post-reionization Universe show surprisingly large opacity fluctuations over rather large (≥50 h-1 comoving Mpc) spatial scales. We model these fluctuations using a hybrid approach utilizing the large-volume Millennium simulation to predict the spatial distribution of QSOs combined with smaller scale full hydrodynamical simulation performed with RAMSES and post-processed with the radiative transfer code ATON. We produce realistic mock absorption spectra that account for the contribution of galaxies and QSOs to the ionizing UV background. These improved models confirm our earlier findings that a significant ( ≳ 50 per cent) contribution of ionizing photons from QSOs can explain the large reported opacity fluctuations on large scales. The inferred QSO luminosity function is thereby consistent with recent estimates of the space density of QSOs at this redshift. Our simulations still somewhat struggle, however, to reproduce the very long (110 h-1 comoving Mpc) high-opacity absorption through observed in ULAS J0148+0600, perhaps suggesting an even later end of reionization than assumed in our previously favoured model. Medium-deep/medium area QSO surveys as well as targeted searches for the predicted strong transverse QSO proximity effect would illuminate the origin of the observed large-scale opacity fluctuations. They would allow us to substantiate whether UV fluctuations due to QSO are indeed primarily responsible, or whether significant contributions from other recently proposed mechanisms such as large-scale fluctuations in temperature and mean free path (even in the absence of rare bright sources) are required.

  17. An 80-kpc Lyα halo around a high-redshift type-2 quasi-stellar object

    Science.gov (United States)

    Smith, D. J. B.; Jarvis, M. J.; Simpson, C.; Martínez-Sansigre, A.

    2009-02-01

    We announce the discovery of an extended emission-line region associated with a high-redshift type-2 quasi-stellar object (QSO). The halo, which was discovered in our new wide-field narrow-band survey, resides at z = 2.85 in the Spitzer First Look Survey region and is extended over ~80 kpc. Deep very long baseline interferometry (VLBI) observations imply that approximately 50 per cent of the radio emission is extended on scales >200pc. The inferred active galactic nuclei (AGN) luminosity is sufficient to ionize the extended halo, and the optical emission is consistent with being triggered coevally with the radio source. The Lyα halo is as luminous as those found around high-redshift radio galaxies; however, the active nucleus is several orders of magnitude less luminous at radio wavelengths than those Fanarof-Riley type II (FRIIs) more commonly associated with extended emission-line regions. AMS05 appears to be a high-redshift analogue to the radio-quiet quasar E1821+643 which is core dominated, but which also exhibits extended Fanarof-Riley type I (FRI)-like structure and contains an optically powerful AGN. We also find evidence for more quiescent kinematics in the Lyα emission line in the outer regions of the halo, reminiscent of the haloes around the more powerful FRIIs. The optical to mid-infrared spectral energy distribution is well described by a combination of an obscured QSO (Lbol ~ 3.4 +/- 0.2 × 1013Lsolar) and a 1.4 Gyr old simple stellar population with mass ~3.9 +/- 0.3 × 1011Msolar.

  18. Mg II Absorption Systems in SDSS QSO Spectra

    CERN Document Server

    Nestor, D B; Rao, S M

    2004-01-01

    We present the results of a MgII absorption-line survey using QSO spectra from the SDSS EDR. Over 1,300 doublets with rest equivalent widths greater than 0.3\\AA and redshifts $0.366 \\le z \\le 2.269$ were identified and measured. We find that the $\\lambda2796$ rest equivalent width ($W_0^{\\lambda2796}$) distribution is described very well by an exponential function $\\partial N/\\partial W_0^{\\lambda2796} = \\frac{N^*}{W^*} e^{-\\frac{W_0}{W^*}}$, with $N^*=1.187\\pm0.052$ and $W^*=0.702\\pm0.017$\\AA. Previously reported power law fits drastically over-predict the number of strong lines. Extrapolating our exponential fit under-predicts the number of $W_0 \\le 0.3$\\AA systems, indicating a transition in $dN/dW_0$ near $W_0 \\simeq 0.3$\\AA. A combination of two exponentials reproduces the observed distribution well, suggesting that MgII absorbers are the superposition of at least two physically distinct populations of absorbing clouds. We also derive a new redshift parameterization for the number density of $W_0^{\\lambd...

  19. On the Formation of Molecular Clumps in QSO Outflows

    CERN Document Server

    Ferrara, Andrea

    2016-01-01

    We study the origin of the cold molecular clumps in quasar outflows, recently detected in CO and HCN emission. We first describe the physical properties of such radiation-driven outflows and show that a transition from a momentum- to an energy-driven flow must occur at a radial distance of R ~ 0.25 kpc. During this transition, the shell of swept up material fragments due to Rayleigh-Taylor instabilities, but these clumps contain little mass and are likely to be rapidly ablated by the hot gas in which they are immersed. We then explore an alternative scenario in which clumps form from thermal instabilities at R >~ 1 kpc, possibly containing enough dust to catalyze molecule formation. We investigate this processes with 3D two-fluid (gas+dust) numerical simulations of a kpc^3 patch of the outflow, including atomic and dust cooling, thermal conduction, dust sputtering, and photoionization from the QSO radiation field. In all cases, dust grains are rapidly destroyed in ~10,000 years; and while some cold clumps for...

  20. Gravitationally lensed extended sources: the case of QSO RXJ0911

    Institute of Scientific and Technical Information of China (English)

    Do Thi Hoai; Pham Tuyet Nhung; Pham Tuan Anh; Frederic Boone; Pierre Darriulat; Pham Ngoc Diep; Pham Ngoc Dong

    2013-01-01

    After a brief reminder of the mechanism of gravitational lensing of extended sources,the particular case of the host galaxy of QSO RXJ0911,a high redshift (z ~ 2.8) quadruply imaged quasar,is explored.The non linearity of the problem,together with the proximity of the source to a cusp of the lens inner caustic,has important consequences on the dependence of the image appearance on the size and shape of the source.Their expected main features and their interpretation in terms of source extension and shape are investigated in a spirit of simplicity and in preparation for the analysis of high sensitivity and spatial resolution images that will soon be within reach with the completion of the Atacama Large Millimeter/submillimeter Array (ALMA).In particular,the information on source size carried by relative image brightness is discussed.Extension of the results to other types of quadruply imaged quasars is briefly considered.

  1. Green Pea Galaxies Reveal Secrets of Lyα Escape

    Science.gov (United States)

    Yang, Huan; Malhotra, Sangeeta; Gronke, Max; Rhoads, James E.; Dijkstra, Mark; Jaskot, Anne; Zheng, Zhenya; Wang, Junxian

    2016-04-01

    We analyze archival Lyα spectra of 12 “Green Pea” galaxies observed with the Hubble Space Telescope, model their Lyα profiles with radiative transfer models, and explore the dependence of the Lyα escape fraction on various properties. Green Pea galaxies are nearby compact starburst galaxies with [O iii] λ5007 equivalent widths (EWs) of hundreds of Å. All 12 Green Pea galaxies in our sample show Lyα lines in emission, with an Lyα EW distribution similar to high-redshift Lyα emitters. Combining the optical and UV spectra of Green Pea galaxies, we estimate their Lyα escape fractions and find correlations between Lyα escape fraction and kinematic features of Lyα profiles. The escape fraction of Lyα in these galaxies ranges from 1.4% to 67%. We also find that the Lyα escape fraction depends strongly on metallicity and moderately on dust extinction. We compare their high-quality Lyα profiles with single H i shell radiative transfer models and find that the Lyα escape fraction anticorrelates with the derived H i column densities. Single-shell models fit most Lyα profiles well, but not the ones with the highest escape fractions of Lyα. Our results suggest that low H i column density and low metallicity are essential for Lyα escape and make a galaxy an Lyα emitter.

  2. TensorLy: Tensor Learning in Python

    OpenAIRE

    Kossaifi, Jean; Panagakis, Yannis; Pantic, Maja

    2016-01-01

    Tensor methods are gaining increasing traction in machine learning. However, there are scant to no resources available to perform tensor learning and decomposition in Python. To answer this need we developed TensorLy. TensorLy is a state of the art general purpose library for tensor learning. Written in Python, it aims at following the same standard adopted by the main projects of the Python scientific community and fully integrating with these. It allows for fast and straightforward tensor d...

  3. He II Ly{beta} GUNN-PETERSON ABSORPTION: NEW HST OBSERVATIONS AND THEORETICAL EXPECTATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Syphers, David; Pieri, Matthew; Shull, J. Michael [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Anderson, Scott F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Zheng, Wei; Kriss, Gerard A. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Smith, Britton [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Meiksin, Avery [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Schneider, Donald P. [Department of Physics and Astronomy, Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G., E-mail: David.Syphers@colorado.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2011-12-01

    Observations of He II Ly{alpha} Gunn-Peterson troughs have proved to be a valuable probe of the epoch of helium reionization at z {approx} 3. Since this optical depth can become unmeasurably large even for modest He II fractions, various alternate techniques have been proposed to push to higher redshift, and among the more promising is looking at higher-order Lyman-series troughs. We here report four new observations of the He II Ly{beta} trough, including new data on the only sightline with a prior Ly{beta} observation. However, the effective optical depth ratio {tau}{sub eff,{beta}}/{tau}{sub eff,{alpha}} is not simply predicted by f{sub {beta}}{lambda}{sub {beta}}/f{sub {alpha}}{lambda}{sub {alpha}} = 0.16, and we analyze cosmological simulations to find that the correct ratio for helium at z {approx} 3 is {approx_equal}0.35. In one case we infer {tau}{sub eff,{alpha}} > 8.8, strong evidence that helium was not fully reionized at z = 3.2-3.5, in agreement with previous measurements suggesting a later completion of reionization.

  4. The Lyα Reference Sample

    DEFF Research Database (Denmark)

    Ostlin, Goran; Hayes, Matthew; Duval, Florent

    2014-01-01

    The Lyα Reference Sample (LARS) is a substantial program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the detailed astrophysics of the visibility and strength of the Lyαline of neutral hydrogen. Lyα is the dominant spectral...... are produced (whether or not they escape), we demanded an Hα equivalent width W(Hα) ≥100 Å. The final sample of 14 galaxies covers far-UV (FUV, λ ~ 1500 Å) luminosities that overlap with those of high-z Lyα emitters (LAEs) and Lyman break galaxies (LBGs), making LARS a valid comparison sample. We present......) but strongly asymmetric Lyα emission. Spectroscopy from the Cosmic Origins Spectrograph on board HST centered on the brightest UV knot shows a moderate outflow in the neutral interstellar medium (probed by low ionization stage absorption features) and Lyα emission with an asymmetric profile. Radiative transfer...

  5. Improving photometric redshifts with Ly$\\alpha$ tomography

    CERN Document Server

    Schmittfull, Marcel

    2016-01-01

    Forming a three dimensional view of the Universe is a long-standing goal of astronomical observations, and one that becomes increasingly difficult at high redshift. In this paper we discuss how tomography of the intergalactic medium (IGM) at $z\\simeq 2.5$ can be used to estimate the redshifts of massive galaxies in a large volume of the Universe based on spectra of galaxies in their background. Our method is based on the fact that hierarchical structure formation leads to a strong dependence of the halo density on large-scale environment. A map of the latter can thus be used to refine our knowledge of the redshifts of halos and the galaxies and AGN which they host. We show that tomographic maps of the IGM at a resolution of $2.5\\,h^{-1}$Mpc can determine the redshifts of more than 90 per cent of massive galaxies with redshift uncertainty $\\Delta z/(1+z)=0.01$. Higher resolution maps allow such redshift estimation for lower mass galaxies and halos.

  6. Metal Enrichment of $Ly-\\alpha$ Clouds and Intergalactic Medium

    CERN Document Server

    Murakami, I; Murakami, Izumi; Yamashita, Kazuyuki

    1997-01-01

    We have examined the metal enrichment of the intergalactic medium (IGM) based on a galactic wind model. A galactic wind driven by supernovae brings metallic gas to the IGM but not so far beyond the gravitational potential. The expanding velocity of the outflow depends on the star formation timescale. Examining 3D calculation for the IGM in CDM model, we find that only 10 % region has metallicity larger than $10^{-2}Z_{\\odot}$ at $z=3$. Wide range of the IGM metallicity produces variety of CIV column densities for a fixed HI column density.

  7. Broad Ly alpha Emission from Three Nearby BL Lacertae Objects

    CERN Document Server

    Stocke, John T; Perlman, Eric S

    2011-01-01

    We present far-UV HST/COS spectra of four nearby BL Lac Objects. BL Lac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lya emission in HST/COS spectra of Mrk421 (z=0.030) and PKS2005-489 (z=0.071) as well as an archival HST/GHRS observation of Mrk501 (z=0.0337). Archival HST/STIS observations of PKS2155-304 (z=0.116) show no Lya emission to a very low upper limit. Using the assumption that the broad-line region (BLR) clouds are asymmetrically placed around the AGN, we use these measured Lya emission features to constrain either the relativistic Gamma values for the ionizing continuum produced by the jet (in the ionization-bounded case) or the mass of warm gas (in the density-bounded case). While realistic Gamma values can be obtained for all four cases, the values for Mrk421 and PKS2155-304 are hig...

  8. Constraining the dark energy with Ly-alpha forest

    CERN Document Server

    Seljak, U; McDonald, P; Seljak, Uros; Mandelbaum, Rachel; Donald, Patrick Mc

    2002-01-01

    Statistical properties of gas absorption in high redshift quasars such as power spectrum and bispectrum allow one to determine the evolution of structure over the redshift range 20.1-0.2 at z>2. In combination with low redshift studies one can place useful limits on the time evolution of the equation of state.

  9. Lyα-Emitting Galaxies at Redshift z~ 4.5 in the LALA Cetus Field

    Science.gov (United States)

    Wang, Jun-Xian; Malhotra, Sangeeta; Rhoads, James E.; Zhang, Hao-Tong; Finkelstein, Steven L.

    2009-11-01

    We present a large sample of Lyα-emitting galaxies (LAEs) spectroscopically confirmed at redshift z ≈ 4.5, based on Inamori-Magellan Areal Camera and Spectrograph spectroscopic observations of candidate z≈ 4.5 Lyα-emitting galaxies in the large area Lyman alpha (LALA) narrowband imaging survey Cetus field. We identify 110 of them as z ≈ 4.5 Lyα emitters based on single-line detections with no continuum emission blueward of the line. Six foreground galaxies are identified, either based on multiple lines or blueward continuum emission. The Lyα confirmation rate varies from <50% to 76% for candidates selected in different narrowband filters at slightly different redshifts. We find a drop in the LAE density at redshift 4.50 ± 0.03 from redshift 4.39 to 4.47 by a factor of 66%, which could be a large-scale void in the distribution of star-forming galaxies (~18 Mpc along the line of sight and ~80 Mpc across). The sample includes many objects with equivalent widths (EWs) gsim200 Å. These large EW candidates are spectroscopically confirmed at the same rate as candidates with more modest EWs. A composite spectrum of all 110 confirmed LAEs shows the characteristic asymmetry of the Lyα line. It also places new and stringent upper limits on the C IV 1549 Å/Lyα and He II 1640 Å/Lyα line ratios, providing a new upper limit on the fraction of active galactic nuclei in Lyα selected galaxy samples, and on the contribution of Pop III populations. Finally, we calculate the Lyα luminosity function for our z ≈ 4.5 sample, which is consistent with those at other redshifts, showing that there is no evolution in Lyα luminosity function from z = 3.1 to 6.6. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

  10. Polarimetry of the HI Lyman-alpha for coronal magnetic field diagnostics

    Science.gov (United States)

    Fineschi, Silvano; Hoover, Richard B.; Zukic, Muamer; Kim, Jongmin; Walker, Arthur B. C., Jr.; Baker, Phillip, C.

    1993-01-01

    We discuss and analyze the possible sources of observational and instrumental uncertainty that can be encountered in measuring magnetic fields of the solar corona through polarimetric observations of the Hanle effect of the coronal Ly-alpha line. The Hanle effect is the modification of the linear polarization of a resonantly scattered line, due to the presence of a magnetic field. Simulated observations are used to examine how polarimetric measurements of this effect are affected by the line-of-sight integration, the electron collisions, and the Ly-alpha geocorona. We plan to implement the coronal magnetic field diagnostics via the Ly-alpha Hanle effect using an all-reflecting Ly-alpha coronagraph/polarimeter (Ly-alphaCoPo) which employs reflecting multilayer mirrors, polarizers, and filters. We discuss here the requirements for such an instrument, and analyze the sources of instrumental uncertainty for polarimetric observations of the coronal Ly-alpha Hanle effect. We conclude that the anticipated polarization signal from the corona and the expected performance of the Ly-alphaCoPo instrument are such that the Ly-alpha Hanle effect method for coronal field diagnostics is feasible.

  11. Optical and X-ray Spectroscopy of 1E 0449.4-1823 Demise of the original type 2 QSO

    CERN Document Server

    Halpern, J P; Forster, K; Halpern, Jules P.; Eracleous, Michael; Forster, Karl

    1998-01-01

    New optical spectra of the original narrow-line quasar 1E 0449.4-1823 show that it now has broad emission lines of considerable strength, eliminating it as a "type 2 QSO" candidate. We suggest that the behavior of 1E 0449.4-1823 is the same as that of some Seyfert 1.8 and 1.9 galaxies, in which Goodrich attributed long-term variations of their broad Balmer lines to dynamical motions of obscuring material located in or around the broad-line region. The optical continuum and broad emission-line regions of 1E 0449.4-1823 may still be partly covered in our line of sight, which would explain its large forbidden-line equivalent widths and flat alpha_ox relative to other low-redshift QSOs. Also present are apparent absorption features in the broad Balmer lines and in Mg II, which may be related to the past obscuration and current emergence of the broad-line region. However, it is difficult to distinguish absorption from broad emission-line peaks that are displaced in velocity; we consider the latter a plausible comp...

  12. GREEN PEA GALAXIES REVEAL SECRETS OF Lyα ESCAPE

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huan; Wang, Junxian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China (China); Malhotra, Sangeeta; Rhoads, James E. [Arizona State University, School of Earth and Space Exploration (United States); Gronke, Max; Dijkstra, Mark [Institute of Theoretical Astrophysics, University of Oslo (Norway); Jaskot, Anne [Smith College, Northampton, MA (United States); Zheng, Zhenya, E-mail: yanghuan@mail.ustc.edu.cn, E-mail: huan.y@asu.edu, E-mail: Sangeeta.Malhotra@asu.edu, E-mail: James.Rhoads@asu.edu [Pontificia Universidad Católica de Chile, Santiago (Chile)

    2016-04-01

    We analyze archival Lyα spectra of 12 “Green Pea” galaxies observed with the Hubble Space Telescope, model their Lyα profiles with radiative transfer models, and explore the dependence of the Lyα escape fraction on various properties. Green Pea galaxies are nearby compact starburst galaxies with [O iii] λ5007 equivalent widths (EWs) of hundreds of Å. All 12 Green Pea galaxies in our sample show Lyα lines in emission, with an Lyα EW distribution similar to high-redshift Lyα emitters. Combining the optical and UV spectra of Green Pea galaxies, we estimate their Lyα escape fractions and find correlations between Lyα escape fraction and kinematic features of Lyα profiles. The escape fraction of Lyα in these galaxies ranges from 1.4% to 67%. We also find that the Lyα escape fraction depends strongly on metallicity and moderately on dust extinction. We compare their high-quality Lyα profiles with single H i shell radiative transfer models and find that the Lyα escape fraction anticorrelates with the derived H i column densities. Single-shell models fit most Lyα profiles well, but not the ones with the highest escape fractions of Lyα. Our results suggest that low H i column density and low metallicity are essential for Lyα escape and make a galaxy an Lyα emitter.

  13. Characterizing Lyman Alpha Scattering in Nearby Galaxies

    Science.gov (United States)

    Bridge, Joanna; Hayes, Matthew; Melinder, Jens; Östlin, Göran; Gronwall, Caryl

    2017-01-01

    The hydrogen emission line of Lyman alpha (Lyα) has long been recognized as key to studying high redshift star-forming galaxies. However, due to the resonance of the emission line, the path that a Lyα photon takes from emission to eventual escape from the galaxy is essentially a mystery. This scattering poses a problem for using Lyα as a key emission feature of galaxies because it results in Lyα not being observed in all star-forming galaxies, and, in galaxies where it is observed, the place where the photon is originally emitted and where it is observed are two very different things. We discuss here how the Lyman-Alpha Reference Sample (LARS) provides a unique sample of 14 nearby (0.02 Space Telescope imaging. We compare the Lyα/Hα ratios with those expected from pure dust attenuation models, finding that in some cases significant positive departures are found on small scales, consistent with geometrical effects being important on sizes comparable to the HII regions. We then develop a simple scattering model in which we are able to estimate the average path length a Lyα photon travels with respect to non-resonant radiation, and quantifiy the excess dust optical depth to which Lyα radiation may be susceptible.

  14. Giant Lyman-Alpha Nebulae in the Illustris Simulation

    CERN Document Server

    Gronke, Max

    2016-01-01

    Several `giant' Lyman-$\\alpha$ (Ly$\\alpha$) nebulae with extent $\\gtrsim 300\\,$kpc and observed Ly$\\alpha$ luminosity of $\\gtrsim 10^{44}\\,{\\rm erg}\\,{\\rm s}^{-1}\\,{\\rm cm}^{-2}\\,{\\rm arcsec}^{-2}$ have recently been detected, and it has been speculated that their presence hints at a substantial cold gas reservoir in small cool clumps not resolved in modern hydro-dynamical simulations. We use the Illustris simulation to predict the Ly$\\alpha$ emission emerging from large halos ($M > 10^{11.5}M_{\\odot}$) at $z\\sim 2$ and thus test this model. We consider both AGN and star driven ionization, and compared the simulated surface brightness maps, profiles and Ly$\\alpha$ spectra to a model where most gas is clumped below the simulation resolution scale. We find that while the cold clumps boost the Ly$\\alpha$ luminosity especially in the outer regions of the halo -- as expected by previous work -- with Illustris no additional clumping is necessary to explain the extents and luminosities of the `giant Ly$\\alpha$ nebul...

  15. The Lyα-LyC Connection: Evidence for an Enhanced Contribution of UV-faint Galaxies to Cosmic Reionization

    Science.gov (United States)

    Dijkstra, Mark; Gronke, Max; Venkatesan, Aparna

    2016-09-01

    The escape of ionizing Lyman continuum (LyC) photons requires the existence of low-N H i sightlines, which also promote escape of Lyα. We use a suite of 2500 Lyα Monte-Carlo radiative transfer simulations through models of dusty, clumpy interstellar (“multiphase”) media from Gronke & Dijkstra, and compare the escape fractions of Lyα ({f}{{esc}}{{Ly}α }) and LyC radiation ({f}{{esc}}{{ion}}). We find that {f}{{esc}}{{ion}} and {f}{{esc}}{{Ly}α } are correlated: galaxies with a low {f}{{esc}}{{Ly}α } consistently have a low {f}{{esc}}{{ion}}, while galaxies with a high {f}{{esc}}{{Ly}α } exhibit a large dispersion in {f}{{esc}}{{ion}}. We argue that there is increasing observational evidence that Lyα escapes more easily from UV-faint galaxies. The correlation between {f}{{esc}}{{ion}} and {f}{{esc}}{{Ly}α } then implies that UV-faint galaxies contribute more to the ionizing background than implied by the faint-end slope of the UV luminosity function. In multiphase gases, the ionizing escape fraction is most strongly affected by the cloud covering factor, f cl, which implies that {f}{{esc}}{{ion}} is closely connected to the observed Lyα spectral line shape. Specifically, LyC-emitting galaxies typically having narrower, more symmetric line profiles. This prediction is qualitatively similar to that for “shell models.”

  16. A Direct Comparison of HI and Lyα Morphologies in Two LARS Galaxies

    Science.gov (United States)

    Fitzgibbon, Kathleen; Cannon, John M.; Freeland, Emily; Hayes, Matthew; Östlin, Göran; LARS Team

    2016-01-01

    The Lyman-Alpha Reference Sample (LARS) and its extension (eLARS) represent an exhaustive campaign to reverse-engineer galaxies. The main goal is to understand how Lyα is transported within galaxies: what fraction of it escapes, and what physical properties affect Lyα morphology and radiative transport (e.g. dust and gas content, metallicity, kinematics, properties of the stellar population). Neutral hydrogen emission, which can be used to determine a galaxy's structure and kinematics, was observed using the B and C configurations of the Very Large Array in two galaxies from the sample: LARS02 and LARS09. Images of the HI mass surface density and of the intensity weighted HI velocity field were created at angular scales of ~8 arcseconds. Extended HI gas is detected at high significance up to ˜30 kpc from the optical body of LARS02. LARS09 has a severely disturbed optical morphology; our new HI observations reveal that LARS09 is interacting with the nearby field galaxy SDSS J082353.65+280622.2. In combination with direct imaging of the Lyα morphology from the Hubble Space Telescope, this program has produced the first direct comparison of Lyα and HI morphologies. These observations demonstrate concept for a significant observational campaign that will produce similar comparisons in the remaining 40 LARS+eLARS galaxies.KF was partially supported by a Science Education Award from the Howard Hughes Medical Institute (HHMI) to Macalester College.

  17. The Connections between QSO Absorption Systems and Galaxies: Low-Redshift Observations

    CERN Document Server

    Tripp, T M; Tripp, Todd M.; Bowen, David V.

    2005-01-01

    Quasar absorption lines have long been recognized to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be studied by any other means. While some pre-Hubble Space Telescope (HST) observations indicated that Mg II absorption lines arise in gaseous galactic halos with a large covering factor, many early QSO absorber studies were hampered by a lack of information about the context of the absorbers and their connections with galaxies. By providing access to crucial ultraviolet resonance lines at low redshifts, deployment of HST and the Far Ultraviolet Spectroscopic Explorer enabled detailed studies of the relationships between QSO absorbers and galaxies. The advent of large surveys such as the Sloan Digital Sky Survey (SDSS) has also advanced the topic by greatly improving the size of absorber and galaxy samples. This paper briefly reviews some observational results on absorber-galaxy...

  18. The Lyα emission from high- z galaxies hosting strong damped Lyα systems

    Science.gov (United States)

    Joshi, Ravi; Srianand, Raghunathan; Noterdaeme, Pasquier; Petitjean, Patrick

    2017-02-01

    We study the average Lyα emission associated with high-z strong (log N(H I) ≥ 21) damped Lyα systems (DLAs). We report Lyα luminosities (LLyα) for the full as well as various sub-samples based on N(H I), z, (r - i) colours of QSOs and rest equivalent width of Si IIλ1526 line (i.e. W1526). For the full sample, we find LLyα level detection of Lyα emission in the red part of the DLA trough. The LLyα is found to be higher for systems with higher W1526 with its peak, detected at ≥3σ, redshifted by about 300-400 km s-1 with respect to the systemic absorption redshift, as seen in Lyman break galaxies (LBGs) and Lyα emitters. A clear signature of a double-hump Lyα profile is seen when we consider W1526 ≥0.4 Å and (r - i) radiation that is 4-10 times stronger than the metagalactic UV background at these redshifts. The relationship between the SFR and surface mass density of atomic gas seen in DLAs is similar to that of local dwarf and metal-poor galaxies. We show that the low-luminosity galaxies will contribute appreciably to the stacked spectrum if the size-luminosity relation seen for H I at low z is also present at high-z. Alternatively, large Lyα haloes seen around LBGs could also explain our measurements.

  19. Evidence for the presence of dust in intervening QSO absorbers from the Sloan Digital Sky Survey

    CERN Document Server

    Khare, P; Vanden Berk, Daniel E; Kulkarni, V P; Crotts, A P S; Welty, D E; Lauroesch, J T; Richards, G T; Alsayyad, Y; Kumar, A; Lundgren, B; Shanidze, N; Vanlandingha, J; Baugher, B; Hall, P B; Jenkins, E B; Ménard, B; Rao, S; Turnshek, D A; Yip, C W

    2005-01-01

    We find evidence for dust in the intervening QSO absorbers from the spectra of QSOs in the Sloan Digital Sky Survey Data Release 1. No evidence is found for the 2175 A feature which is present in the Milky Way dust extinction curve. The extinction curve resembles the SMC extinction curve. The observed Delta(g-i) excess for QSOs with strong absorption systems appears to be a result of the reddening due to dust in the intervening absorbers.

  20. Lyman-alpha Absorption from Heliosheath Neutrals

    CERN Document Server

    Wood, B E; Linsky, J L; Malama, Y G; Wood, Brian E.; Izmodenov, Vladislav V.; Linsky, Jeffrey L.; Malama, Yury G.

    2006-01-01

    We assess what information HST observations of stellar Ly-alpha lines can provide on the heliosheath, the region of the heliosphere between the termination shock and heliopause. To search for evidence of heliosheath absorption, we conduct a systematic inspection of stellar Ly-alpha lines reconstructed after correcting for ISM absorption (and heliospheric/astrospheric absorption, if present). Most of the stellar lines are well centered on the stellar radial velocity, as expected, but the three lines of sight with the most downwind orientations relative to the ISM flow (Chi1 Ori, HD 28205, and HD 28568) have significantly blueshifted Ly-alpha lines. Since it is in downwind directions where heliosheath absorption should be strongest, the blueshifts are almost certainly caused by previously undetected heliosheath absorption. We make an initial comparison between the heliosheath absorption and the predictions of a pair of heliospheric models. A model with a complex multi-component treatment of plasma within the he...

  1. The MUSE QSO Blind Survey: A Census of Absorber Host Galaxies

    Science.gov (United States)

    Straka, Lorrie A.; MUSE GTO Consortium

    2017-03-01

    Understanding the distribution of gas in galaxies and its interaction with the IGM is crucial to complete the picture of galaxy evolution. At all redshifts, absorption features seen in QSO spectra serve as a unique probe of the gaseous content of foreground galaxies and the IGM, extending out to 200 kpc. Studies show that star formation history is intimately related to the co-evolution of galaxies and the IGM. In order to study the environments traced by absorption systems and the role of inflows and outflows, it is critical to measure the emission properties of host galaxies and their halos. We overcome the challenge of detecting absorption host galaxies with the MUSE integral field spectrograph on VLT. MUSE's large field of view and sensitivity to emission lines has allowed a never-before seen match between the number density of absorbers along QSO sightlines and the number density of emission line galaxies within 200 kpc of the QSO. These galaxies represent a sample for which previously elusive connections can be made between mass, metallicity, SFR, and absorption.

  2. Detection of weak gravitational lensing magnification from Galaxy-QSO cross-correlation in the SDSS

    CERN Document Server

    Gaztañaga, E

    2003-01-01

    We report a detection of galaxy-QSO cross-correlation w_{GQ} in the Sloan Digital Sky Survey (SDSS) Early Data Release (EDR) over 0.2-30 arc-minute scales. We cross-correlate galaxy samples of different mean depths r'=19-22 (z_G =0.15-0.35) with the main QSO population (i'_Q <19.2) at \\zbar_Q \\simeq 1.6. We find positive detection in most cases (except for the faintest QSOs as expeceted) with up to 8-sigma significance. The amplitude of the signal on arc-minute scales is about 20% at z_G=0.15 decreasing to 10% at z_G =0.35 This is a few times larger than currently expected from structure formation LCDM models o but confirms, at a higher significance, previous measurements by several groups. The shape and redshift evolution agrees well with being a lensing signal. We also find a 3-sigma detection for the (pseudo) skewness (galaxy-galaxy-QSO correlation): S_3 = 18.6 \\pm 5.7$ The data indicates very strong non-linear amplitude for the underlaying matter fluctuations scales of 0.2$ Mpc/h, in apparent contradic...

  3. The ALHAMBRA survey: Discovery of a faint QSO at z = 5.41

    CERN Document Server

    Matute, I; Márquez, I; Fernández-Soto, A; Husillos, C; del Olmo, A; Perea, J; Pović, M; Ascaso, B; Alfaro, E J; Moles, M; Aguerri, J A L; Aparicio--Villegas, T; Benítez, N; Broadhurst, T; Cabrera--Cano, J; Castander, F J; Cepa, J; Cerviño, M; Cristóbal-Hornillos, D; Infante, L; Delgado, R M González; Martínez, V J; Molino, A; Prada, F; Quintana, J M

    2013-01-01

    We aim to illustrate the potentiality of the Advanced Large, Homogeneous Area, Medium-Band Redshift Astronomical (ALHAMBRA) survey to investigate the high redshift universe through the detection of quasi stellar objects (QSOs) at redshifts larger than 5. The search for z>5 QSOs candidates was done by fitting an extensive library of spectral energy distributions --including active and non-active galaxy templates as well as stars-- to the photometric database of the ALHAMBRA survey (composed of 20 optical medium-band plus the 3 broad-band JHKs filters). Our selection over ~1 square degree of ALHAMBRA data (~1/4 of the total area covered by the survey), combined with GTC/OSIRIS spectroscopy, has yielded the identification of an optically faint QSO at very high redshift (z = 5.41). The QSO has an absolute magnitude of ~-24 at the 1450{\\AA} continuum, a bolometric luminosity of ~2x10^46 erg/s and an estimated black hole mass of ~10^8 Msolar. This QSO adds itself to a reduced number of known UV faint sources at the...

  4. Automatic QSO Selection Using Machine Learning: Application on Massive Astronomical Database

    Science.gov (United States)

    Kim, D.-W.; Protopapas, P.; Alcock, C.; Byun, Y.-I.; Khardon, R.

    2011-07-01

    We present a new QSO (Quasi-Stellar Object) selection algorithm using Support Vector Machine (SVM), a supervised classification method, on a set of multiple extracted times series features such as period, amplitude, color, and autocorrelation value. We train a model that separates QSOs from variable stars, non-variable stars and microlensing events using the richest possible training set consisting of all known types of variables including QSOs from the MAssive Compact Halo Object (MACHO) database. We applied the trained model on the MACHO Large Magellanic Cloud (LMC) dataset, which consists of 40 million lightcurves, and found 1,620 QSO candidates. During the selection none of the 33,242 known MACHO variables were misclassified as QSO candidates. In order to estimate the true false positive rate, we crossmatched the candidates with astronomical catalogs including the Spitzer Surveying the Agents of a Galaxy's Evolution (SAGE) LMC catalog. The results further suggest that the majority of the candidates, more than 70%, are QSOs.

  5. Escape of Lyα and continuum photons from star-forming galaxies

    Science.gov (United States)

    Yajima, Hidenobu; Li, Yuexing; Zhu, Qirong; Abel, Tom; Gronwall, Caryl; Ciardullo, Robin

    2014-05-01

    A large number of high-redshift galaxies have been discovered via their narrow-band Lyα line or broad-band continuum colours in recent years. The nature of the escaping process of photons from these early galaxies is crucial to understand galaxy evolution and the cosmic reionization. Here, we investigate the escape of Lyα, non-ionizing UV-continuum (λ = 1300-1600 Å in rest frame), and ionizing photons (λ emissivity of Lyman Alpha Emitters (LAEs). By combining this relation with the observed luminosity functions of LAEs at different redshift, we estimate the contribution from LAEs to the reionization of intergalactic medium (IGM). Our result suggests that ionizing photons from LAEs alone are not sufficient to ionize IGM at z ≳ 6, but they can maintain the ionization of IGM at z ˜ 0-5.

  6. An excess of damped Lyman alpha galaxies near QSOs

    CERN Document Server

    Russell, D M; Ellison, S L; Benn, Chris R.; Ellison, Sara L.; Russell, David M.

    2006-01-01

    We present a sample of 33 damped Lyman alpha systems (DLAs) discovered in the Sloan Digital Sky Survey (SDSS) whose absorption redshifts (z_abs) are within 6000 km/s of the QSO's systemic redshift (z_sys). Our sample is based on 731 2.5 = 2e20 cm^-2. The derived number density of DLAs per unit redshift, n(z), within v < 6000 km/s is higher (3.5 sigma significance) by almost a factor of 2 than that of intervening absorbers observed in the SDSS DR3, i.e. there is evidence for an overdensity of galaxies near the QSOs. This provides a physical motivation for excluding DLAs at small velocity separations in surveys of intervening 'field' DLAs. In addition, we find that the overdensity of proximate DLAs is independent of the radio-loudness of the QSO, consistent with the environments of radio-loud and radio-quiet QSOs being similar.

  7. The primordial deuterium abundance: subDLA system at zabs = 2.437 towards the QSO J 1444+2919

    Science.gov (United States)

    Balashev, S. A.; Zavarygin, E. O.; Ivanchik, A. V.; Telikova, K. N.; Varshalovich, D. A.

    2016-05-01

    We report a new detection of neutral deuterium in the sub-Damped Lyman Alpha system with low metallicity [O/H] = -2.042 ± 0.005 at zabs = 2.437 towards QSO J 1444+2919. The hydrogen column density in this system is logN(H I) =19.983 ± 0.010 and the measured value of deuterium abundance is log(D/H) = -4.706 ± 0.007stat ± 0.067syst. This system meets the set of strict selection criteria stated recently by Cooke et al. 2014 and, therefore, widens the Precision Sample of D/H. However, possible underestimation of systematic errors can bring a bias into the mean D/H value (especially if one uses a weighted mean). Hence, it might be reasonable to relax these selection criteria and thus increase the number of acceptable absorption systems with measured D/H values. The unweighted mean value of 15 robust D/H measurements gives a conservative value of the primordial deuterium abundance (D/H)p = (2.54 ± 0.19) × 10-5 which is in good agreement with the prediction given by analysis of the cosmic microwave background radiation for the standard big bang nucleosynthesis. By means of the derived unweighted mean (D/H)p value the baryon density of the Universe Ωbh2 = 0.0218 ± 0.0010 and the baryon-to-photon ratio η = (5.96 ± 0.27) × 10-10 have been deduced. These values have confidence intervals which are less stringent than that obtained for the Precision Sample and, thus, leave a broader window for new physics. The latter is particularly important in the light of the lithium problem.

  8. Resolving the Optical Emission Lines of Lyα Blob "B1" at z = 2.38: Another Hidden Quasar

    Science.gov (United States)

    Overzier, R. A.; Nesvadba, N. P. H.; Dijkstra, M.; Hatch, N. A.; Lehnert, M. D.; Villar-Martín, M.; Wilman, R. J.; Zirm, A. W.

    2013-07-01

    We have used the SINFONI near-infrared integral field unit on the Very Large Telescope to resolve the optical emission line structure of one of the brightest (L Lyα ≈ 1044 erg s-1) and nearest (z ≈ 2.38) of all Lyα blobs (LABs). The target, known in the literature as object "B1", lies at a redshift where the main optical emission lines are accessible in the observed near-infrared. We detect luminous [O III] λλ4959, 5007 and Hα emission with a spatial extent of at least 32 × 40 kpc (4'' × 5''). The dominant optical emission line component shows relatively broad lines (600-800 km s-1, FWHM) and line ratios consistent with active galactic nucleus (AGN) photoionization. The new evidence for AGN photoionization, combined with previously detected C IV and luminous, warm infrared emission, suggest that B1 is the site of a hidden quasar. This is confirmed by the fact that [O II] is relatively weak compared with [O III] (extinction-corrected [O III]/[O II] of about 3.8), which is indicative of a high, Seyfert-like ionization parameter. From the extinction-corrected [O III] luminosity we infer a bolometric AGN luminosity of ~3 × 1046 erg s-1, and further conclude that the obscured AGN may be Compton-thick given existing X-ray limits. The large line widths observed are consistent with clouds moving within the narrow-line region of a luminous QSO. The AGN scenario is capable of producing sufficient ionizing photons to power the Lyα, even in the presence of dust. By performing a census of similar objects in the literature, we find that virtually all luminous LABs harbor obscured quasars. Based on simple duty-cycle arguments, we conclude that AGNs are the main drivers of the Lyα in LABs rather than the gravitational heating and subsequent cooling suggested by cold stream models. We also conclude that the empirical relation between LABs and overdense environments at high redshift must be due to a more fundamental correlation between AGNs (or massive galaxies) and

  9. Exploring Damped Lyα System Host Galaxies Using Gamma-Ray Bursts

    Science.gov (United States)

    Toy, Vicki L.; Cucchiara, Antonino; Veilleux, Sylvain; Fumagalli, Michele; Rafelski, Marc; Rahmati, Alireza; Cenko, S. Bradley; Capone, John I.; Pasham, Dheeraj R.

    2016-12-01

    We present a sample of 45 Damped Lyα system (DLA; {N}{{H}{{I}}} ≥slant 2× {10}20 {{cm}}-2) counterparts (33 detections, 12 upper limits) which host gamma-ray bursts (GRB-DLAs) in order to investigate star formation and metallicity within galaxies hosting DLAs. Our sample spans z˜ 2{--}6 and is nearly three times larger than any previously detected DLA counterparts survey based on quasar line-of-sight searches (QSO-DLAs). We report star formation rates (SFRs) from rest-frame UV photometry and spectral energy distribution modeling. We find that DLA counterpart SFRs are not correlated with either redshift or H i column density. Thanks to the combination of Hubble Space Telescope and ground-based observations, we also investigate DLA host star formation efficiency. Our GRB-DLA counterpart sample spans both higher efficiency and low efficiency star formation regions compared to the local Kennicutt-Schmidt relation, local star formation laws, and z˜ 3 cosmological simulations. We also compare the depletion times of our DLA hosts sample to other objects in the local universe; our sample appears to deviate from the star formation efficiencies measured in local spiral and dwarf galaxies. Furthermore, we find similar efficiencies as local inner disks, SMC, and Lyman-break galaxy outskirts. Finally, our enrichment time measurements show a spread of systems with under- and over-abundance of metals, which may suggest that these systems had episodic star formation and a metal enrichment/depletion as a result of strong stellar feedback and/or metal inflow/outflow.

  10. Clustering of galaxies near damped Lyman-alpha systems with (z) = 2.6

    Science.gov (United States)

    Wolfe, A. M

    1993-01-01

    The galaxy two-point correlation function, xi, at (z) = 2.6 is determined by comparing the number of Ly-alpha-emitting galaxies in narrowband CCD fields selected for the presence of damped L-alpha absorption to their number in randomly selected control fields. Comparisons between the presented determination of (xi), a density-weighted volume average of xi, and model predictions for (xi) at large redshifts show that models in which the clustering pattern is fixed in proper coordinates are highly unlikely, while better agreement is obtained if the clustering pattern is fixed in comoving coordinates. Therefore, clustering of Ly-alpha-emitting galaxies around damped Ly-alpha systems at large redshifts is strong. It is concluded that the faint blue galaxies are drawn from a parent population different from normal galaxies, the presumed offspring of damped Ly-alpha systems.

  11. A systematic study of Lyman-Alpha transfer through outflowing shells: Model parameter estimation

    CERN Document Server

    Gronke, Max; Dijkstra, Mark

    2015-01-01

    Outflows promote the escape of Lyman-$\\alpha$ (Ly$\\alpha$) photons from dusty interstellar media. The process of radiative transfer through interstellar outflows is often modelled by a spherically symmetric, geometrically thin shell of gas that scatters photons emitted by a central Ly$\\alpha$ source. Despite its simplified geometry, this `shell model' has been surprisingly successful at reproducing observed Ly$\\alpha$ line shapes. In this paper we perform automated line fitting on a set of noisy simulated shell model spectra, in order to determine whether degeneracies exist between the different shell model parameters. While there are some significant degeneracies, we find that most parameters are accurately recovered, especially the HI column density ($N_{\\rm HI}$) and outflow velocity ($v_{\\rm exp}$). This work represents an important first step in determining how the shell model parameters relate to the actual physical properties of Ly$\\alpha$ sources. To aid further exploration of the parameter space, we ...

  12. Usability Study and Improvement of The Äly Excel

    OpenAIRE

    Tolonen, Heli

    2014-01-01

    This Master’s thesis concentrates on a particular tool, called Äly Excel, which is used in health care centres in Finland. The Äly Excel is a Microsoft Excel based tool that helps to plan a health care personnel rota. The main goal of this work was to enhance usability of the Äly Excel. The development work was part of the Hyvä Potku project that is managed by Northern Ostrobothnia Hospital District. To find out the most important usability problems of the Äly Excel, usability tests were...

  13. MAGIC detection of sub-TEV emission from gravitationally lensed blazar QSO B0218+357

    Science.gov (United States)

    Dominis Prester, D.; Sitarek, J.; Becerra, J.; Buson, S.; Lindfors, E.; Manganaro, M.; Mazin, D.; Nievas Rosillo, M.; Nilsson, K.; Stamerra, A.; Tavecchio, F.; Vovk, Ie.; MAGIC Collaboration; Fermi LAT Collaboration

    The blazar QSO B0218+357 is the first gravitationally lensed blazar detected in the very high energy (VHE, E > 100 GeV) gamma-ray spectral range (Ahnen et al. 2016). It is gravitationally lensed by the intervening galaxy B0218+357G (z l = 0.68466 +/- 0.00004, Carilli et al. 1993), which splits the blazar emission into two components, spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 days delay. In July 2014 a flare from QSO B0218+357 was observed by the Fermi-LAT (Large Area Telescope, Atwood et al. 2009, Ackermann et al. 2012), and followed-up by the MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes, a stereoscopic system of two 17m Imaging Atmospheric Cherenkov Telescopes located on La Palma, Canary Islands (Aleksić et al. 2016a, 2016b), during the expected time of arrival of the delayed component of the emission. MAGIC could not observe the leading image due to the Full Moon. The MAGIC and Fermi-LAT observations were accompanied by optical data from KVA telescope at La Palma, and X-ray observations by Swift-XRT (Fig. 1 left). Variability in gamma-rays was of the order of one day, while no variability correlated with gamma-rays was observed at lower energies. The flux ratio of the leading to trailing image in HE gamma-rays was larger than in the flare of QSO B0218+357 observed by Fermi-LAT in 2012 (Cheung et al. 2014). Changes in the observed flux ratio can be caused by gravitational microlensing on individual stars in the host galaxy (Neronov et al. 2015), or by other compact objects like for ex. clumps in giant molecular clouds (Sitarek & Bednarek 2016).

  14. Constraints on QSO emissivity using H I and He II Lyman α forest

    Science.gov (United States)

    Khaire, Vikram

    2017-10-01

    The spectrum of cosmic ultraviolet background radiation at He II ionizing energies (E ≥ 4 Ryd) is important to study the He II reionization, thermal history of the intergalactic medium (IGM) and metal lines observed in quasi-stellar object (QSO) absorption spectra. It is determined by the emissivity of QSOs at E ≥ 4 Ryd obtained from their observed luminosity functions and the mean spectral energy distribution (SED). The SED is approximated as a power law at energies E ≥ 1 Ryd, fE ∝ Eα, where the existing observations constrain the power-law index α only up to ∼2.3 Ryd. Here, we constrain α for E ≥ 4 Ryd using recently measured He II Lyman α effective optical depths (τ_{α }^{He II}), H I photoionization rates and updated H I distribution in the IGM. We find that -1.6 > α > -2 is required to reproduce the τ_{α }^{He II} measurements when we use the QSO emissivity obtained from their luminosity function using optical surveys. We also find that the models where QSOs can alone reionize H I cannot reproduce the τ_{α }^{He II} measurements. These models need modifications, such as a break in mean QSO SED at energies greater than 4 Ryd. Even after such modifications, the predicted He II reionization history, showing that the He II is highly ionized even at z ∼ 5, is significantly different from the standard models. Therefore, the thermal history of the IGM will be crucial to distinguish these models. We also provide the He II photoionization rates obtained from binned τ_{α }^{He II} measurements.

  15. An Intrinsic Model for the Polarization Position Angle Swing Observed in QSO 1150+812

    Institute of Scientific and Technical Information of China (English)

    Shan-Jie Qian; Xi-Zhen Zhang

    2004-01-01

    The rapid polarization position angle swing of ~ 180° observed in QSO 1150+812 at 2cm by Kochenov and Gabuzda is quite a regular event. One interesting property of the event is that, during the time of the swing the polarized flux density remained almost constant. We suggest that such an event can be explained in terms of a relativistic thin shock propagating through a uniform helical magnetic field, giving rise to relativistic aberration effects as the transverse field component rotates. The model may also be applicable to other similar events in which variations in polarization are not accompanied by variations in total flux density.

  16. The TESIS project: Are type 2 QSO hidden in X-ray emitting EROs?

    CERN Document Server

    Severgnini, P; Braito, V; Saracco, P; Longhetti, M; Bender, R; Drory, N; Feulner, G; Hopp, U; Mannucci, F; Maraston, C

    2003-01-01

    Here we present the results obtained from the analysis of 75 ksec of XMM-Newton observations of a sample of EROs selected from one MUNICS field (K'<19.5 mag). We find 6 EROs with a X-ray counterpart down to a 2--10 keV flux limit of ~10^{-15} cgs. For all of them the X-ray--to--optical flux ratios and the 2--10 keV luminosities suggest the presence of AGN. In particular, a complete X-ray spectral analysis shows that high luminosity, obscured AGNs (i.e. QSO2 candidates) are present in 3 of them.

  17. BRIGHT Lights, BIG City: Massive Galaxies, Giant Ly-A Nebulae, and Proto-Clusters

    Energy Technology Data Exchange (ETDEWEB)

    van Breugel, W; Reuland, M; de Vries, W; Stanford, A; Dey, A; Kurk, J; Venemans, B; Rottgering, H; Miley, G; De Breuck, C; Dopita, M; Sutherland, R; Bland-Hawthorn, J

    2002-08-01

    High redshift radio galaxies are great cosmological tools for pinpointing the most massive objects in the early Universe: massive forming galaxies, active super-massive black holes and proto-clusters. They report on deep narrow-band imaging and spectroscopic observations of several z > 2 radio galaxy fields to investigate the nature of giant Ly-{alpha} nebulae centered on the galaxies and to search for over-dense regions around them. They discuss the possible implications for our understanding of the formation and evolution of massive galaxies and galaxy clusters.

  18. Novel approach of LY12 alloy brazing

    Institute of Scientific and Technical Information of China (English)

    薛松柏; 钱乙余; 董健; 吕晓春

    2003-01-01

    The LY12 Al alloy was brazed with the adoption of the improved KF-CsF-AlF3 flux matching Ag-Al-Cu-Zn filler metal. The shear strength of brazed joint could reach 80% of that of the substrate and the tensile strength of butt brazed joint will be 70% of that of the substrate. This was the great progress against the traditional claim that Al alloy reinforced by heat treatment could not be brazed. The experimental results and theoretical analysis had proved that it was the key issue to remove the MgO oxide film below 503℃. The addition of rare earth La was the effective way to obtain better mechanical properties of the filler metal as well as brazed joints.

  19. Lyα luminosity functions at redshift z ≈ 4.5

    Science.gov (United States)

    Zheng, Zhen-Ya; Finkelstein, Steven L.; Finkelstein, Keely; Tilvi, Vithal; Rhoads, James E.; Malhotra, Sangeeta; Wang, Jun-Xian; Miller, Neal; Hibon, Pascale; Xia, Lifang

    2013-06-01

    We present a spectroscopically confirmed sample of Lyman α emitting galaxies (LAEs) at z ˜ 4.5 in the Extended Chandra Deep Field-South (ECDFS), which we combine with a sample of z ˜ 4.5 LAEs from previous narrow-band surveys from the Large Area Lyman Alpha (LALA) survey to build a unified Lyα luminosity function. We spectroscopically observed 64 candidate LAEs in the ECDFS, confirming 46 objects as z ˜ 4.5 LAEs based on single-line detections with no continuum emission bluewards of the line, resulting in a Lyα confirmation rate of ˜70 per cent. We did not detect significant flux from neither the C IV λ1549 Å emission line nor the He II λ1640 Å emission line in individual LAE spectra. These lines were also undetected in a co-added spectrum, with the co-added line ratio of He II to Lyα constraining the Population III star formation rate (SFR) to be 3. Similar luminosity function differences have been used to infer evolution in the neutral gas fraction in the intergalactic medium at z > 6, yet here the difference is likely due to cosmic variance, given that the two samples are from adjoining line-of-sight volumes. Combining our new sample of LAEs with those from previous LALA narrow-band surveys at z = 4.5, we obtain one of the best measured Lyα luminosity functions to date, with our sample of over 200 spectroscopically confirmed Lyα galaxies yielding log10(L*) = 42.83 ± 0.06 (erg s-1) and log10(Φ*) = -3.48 ± 0.09 (Mpc-3). We compare our new luminosity function to others from the literature to study the evolution of the Lyα luminosity density at 0 < z < 7. We find tentative evidence for evolution in the product L*Φ*, which approximately tracks the cosmic SFR density, but since field-to-field and survey-to-survey variations are in some cases as large as the possible evolution, some caution is needed in interpreting this trend.

  20. Spitzer observations of a gravitationally lensed quasar, QSO 2237+0305

    CERN Document Server

    Agol, Eric; Gorjian, Varoujan; Kimball, Amy; 10.1088/0004-637X/697/2/1010

    2009-01-01

    The four-image gravitationally lensed quasar QSO 2237+0305 is microlensed by stars in the lens galaxy. The amplitude of microlensing variability can be used to infer the relative size of the quasar as a function of wavelength; this provides a test of quasar models. Toward this end, we present Spitzer Space Telescope Infrared Spectrograph and Infrared Array Camera (IRAC) observations of QSO 2237+0305, finding the following. (1) The infrared (IR) spectral energy distribution (SED) is similar to that of other bright radio-quiet quasars, contrary to an earlier claim. (2) A dusty torus model with a small opening angle fits the overall shape of the IR SED well, but the quantitative agreement is poor due to an offset in wavelength of the silicate feature. (3) The flux ratios of the four lensed images can be derived from the IRAC data despite being unresolved. We find that the near-IR fluxes are increasingly affected by microlensing toward shorter wavelengths. (4) The wavelength dependence of the IRAC flux ratios is ...

  1. On the Observed W_MgII--L_[OII] Correlation in SDSS QSO Spectra

    CERN Document Server

    López, Gilberto

    2011-01-01

    This paper investigates the effect of differential aperture loss with SDSS fibers and examines whether such selection bias would result in the observed correlation between rest-frame absorption equivalent width of MgII absorbers, Wr(2796), and mean associated [OII] luminosity, L_[OII], in SDSS QSO spectra. We demonstrate based on a Monte Carlo simulation that the observed Wr(2796) vs. L_[OII] correlation of MgII absorbers can be well-reproduced, if all galaxies found in deep surveys possess extended MgII halos and if the extent of MgII halos scales proportionally with galaxy mass as shown in previous studies. The observed correlation can be explained by a combination of (1) the known Wr(2796) vs. rho anti-correlation in galaxy and MgII absorber pairs and (2) an increasing aperture loss in the 3" diameter SDSS fiber for galaxies at larger rho. Galaxies at larger projected distances produce on average weaker MgII absorbers and weaker (or zero) L_[OII] in SDSS QSO spectra. We show that such correlation diminishe...

  2. Optimizing the night time with dome vents and SNR-QSO at CFHT

    Science.gov (United States)

    Devost, Daniel; Mahoney, Billy; Moutou, Claire; CFHT QSO Team, CFHT software Group

    2017-06-01

    Night time is a precious and costly commodity and it is important to get everything we can out of every second of every night of observing. In 2012 the Canada-France-Hawaii Telescope started operating 12 new vent doors installed on the dome over the course of the previous two years. The project was highly successful and seeing measurements show that venting the dome greatly enhances image quality at the focal plane. In order to capitalize on the gains brought by the new vents, the observatory started exploring a new mode of observation called SNR-QSO. This mode consist of a new implementation inside our Queued Service Observation (QSO) system. Exposure times are adjusted for each frame depending on the weather conditions in order to reach a specific depth, Signal to Noise Ratio (SNR) at a certain magnitude. The goal of this new mode is to capitalize on the exquisite seeing provided by Maunakea, complemented by the minimized dome turbulence, to use the least amount of time to reach the depth required by the science programs. Specific implementations were successfully tested on two different instruments, our wide field camera MegaCam and our high resolution spectrograph ESPaDOnS. I will present the methods used for each instrument to achieve SNR observing and the gains produced by these new observing modes in order to reach the scientific goals of accepted programs in a shorter amount of time.

  3. A young star-forming galaxy at z = 3.5 with an extended Ly\\,$α$ halo seen with MUSE

    DEFF Research Database (Denmark)

    Patrício, Vera; Richard, Johan; Verhamme, Anne;

    2016-01-01

    .5$, observed with MUSE, for which we obtain 2D resolved spatial information of Ly$\\alpha$ and, for the first time, of CIII] emission. The exceptional signal-to-noise of the data reveals UV emission and absorption lines rarely seen at these redshifts, allowing us to derive important physical properties (T...

  4. Illuminating gas inflows/outflows in the MUSE deepest fields : Lyα nebulae around forming galaxies at z ≃ 3.3

    NARCIS (Netherlands)

    Vanzella, E.; Balestra, I.; Gronke, M.; Karman, W.; Caminha, G. B.; Dijkstra, M.; Rosati, P.; De Barros, S.; Caputi, K.; Grillo, C.; Tozzi, P.; Meneghetti, M.; Mercurio, A.; Gilli, R.

    2017-01-01

    We report on the discovery of extended Ly-alpha nebulae at z~3.3 in the Hubble Ultra Deep Field (HUDF, ~ 40 kpc X 80 kpc) and behind the Hubble Frontier Fields galaxy cluster MACSJ0416 (~ 40kpc), spatially associated with groups of star-forming galaxies. VLT/MUSE integral field spectroscopy reveals

  5. Crystal Structure of the FGFR4/LY2874455 Complex Reveals Insights into the Pan-FGFR Selectivity of LY2874455.

    Science.gov (United States)

    Wu, Daichao; Guo, Ming; Philips, Michael A; Qu, Lingzhi; Jiang, Longying; Li, Jun; Chen, Xiaojuan; Chen, Zhuchu; Chen, Lin; Chen, Yongheng

    2016-01-01

    Aberrant FGFR4 signaling has been documented abundantly in various human cancers. The majority of FGFR inhibitors display significantly reduced potency toward FGFR4 compared to FGFR1-3. However, LY2874455 has similar inhibition potency for FGFR1-4 with IC50 less than 6.4 nM. To date, there is no published crystal structure of LY2874455 in complex with any kinase. To better understand the pan-FGFR selectivity of LY2874455, we have determined the crystal structure of the FGFR4 kinase domain bound to LY2874455 at a resolution of 2.35 Å. LY2874455, a type I inhibitor for FGFR4, binds to the ATP-binding pocket of FGFR4 in a DFG-in active conformation with three hydrogen bonds and a number of van der Waals contacts. After alignment of the kinase domain sequence of 4 FGFRs, and superposition of the ATP binding pocket of 4 FGFRs, our structural analyses reveal that the interactions of LY2874455 to FGFR4 are largely conserved in 4 FGFRs, explaining at least partly, the broad inhibitory activity of LY2874455 toward 4 FGFRs. Consequently, our studies reveal new insights into the pan-FGFR selectivity of LY2874455 and provide a structural basis for developing novel FGFR inhibitors that target FGFR1-4 broadly.

  6. QSO hosts and environments at z=0.9 to 4.2 $JHK$ images with adaptive optics

    CERN Document Server

    Hutchings, J B; Morris, S L; Durand, D; Steinbring, E

    1998-01-01

    We have observed nine QSOs with redshifts 0.85 to 4.16 at near-IR wavelengths with the adaptive optics bonnette of the Canada-France-Hawaii telescope. Exposure times ranged from 1500 to 24000s (mostly near 7000s) in J, H, or K bands, with pixels 0.035 arcsec on the sky. The FWHM of the co-added images at the location of the quasars are typically 0.16 arcsec. Including another QSO published previously, we find associated QSO structure in at least eight of ten objects, including the QSO at z = 4.16. The structures seen in all cases include long faint features which appear to be tidal tails. In four cases we have also resolved the QSO host galaxy, but find them to be smooth and symmetrical: future PSF removal may expand this result. Including one object previously reported, of the nine objects with more extended structure, five are radio-loud, and all but one of these appear to be in a dense small group of compact galaxy companions. The radio-quiet objects do not occupy the same dense environments, as seen in th...

  7. Mapping the ionised gas around the luminous QSO HE 1029-1401: Evidence for minor merger events?

    CERN Document Server

    Husemann, B; Wisotzki, L; Jahnke, K; Kupko, D; Nugroho, D; Schramm, M

    2010-01-01

    We present VIMOS integral field spectroscopy of the brightest radio-quiet QSO on the southern sky HE 1029-1401 at a redshift of z=0.086. Standard decomposition techniques for broad-band imaging are extended to integral field data in order to deblend the QSO and host emission. We perform a tentative analysis of the stellar continuum finding a young stellar population (<100Myr) or a featureless continuum embedded in an old stellar population (10Gyr) typical for a massive elliptical galaxy. The stellar velocity dispersion of sigma_*=320\\pm90 km/s and the estimated black hole mass log(M_BH/M_sun)=8.7\\pm0.3 are consistent with the local M_BH-sigma_* relation within the errors. For the first time we map the two-dimensional ionised gas distribution and the gas velocity field around HE 1029-1401. While the stellar host morphology is purely elliptical we find a highly structured distribution of ionised gas out to 16 kpc from the QSO. The gas is highly ionised solely by the QSO radiation and has a significantly lowe...

  8. The primordial deuterium abundance: subDLA system at $z_{\\rm abs}=2.437$ towards the QSO J1444+2919

    CERN Document Server

    Balashev, S A; Ivanchik, A V; Telikova, K N; Varshalovich, D A

    2015-01-01

    We report a new detection of neutral deuterium in the sub Damped Lyman Alpha system with low metallicity [O/H]\\,=\\,$-2.042 \\pm 0.005$ at $z_{\\rm abs}=2.437$ towards QSO~J\\,1444$+$2919. The hydrogen column density in this system is log$N$(H\\,{\\sc i})~$=19.983\\pm0.010$ and the measured value of deuterium abundance is log(D/H)~$=-4.706\\pm0.007_{\\rm stat}\\pm0.067_{\\rm syst}$. This system meets the set of strict selection criteria stated recently by Cooke et al. and, therefore, widens the {\\it Precision Sample} of D/H. However, possible underestimation of systematic errors can bring bias into the mean D/H value (especially if use a weighted mean). Hence, it might be reasonable to relax these selection criteria and, thus, increase the number of acceptable absorption systems with measured D/H values. In addition, an unweighted mean value might be more appropriate to describe the primordial deuterium abundance. The unweighted mean value of the whole D/H data sample available to date (15 measurements) gives a conserva...

  9. Exploring the Thermal State of the Low-Density Intergalactic Medium at z=3 with an Ultra-High Signal-to-Noise QSO Spectrum

    CERN Document Server

    Rorai, A; Haehnelt, M G; Carswell, R F; Bolton, J S; Cristiani, S; D'Odorico, V; Cupani, G; Barai, P; Calura, F; Kim, T -S; Pomante, E; Tescari, E; Viel, M

    2016-01-01

    At low densities the standard ionisation history of the intergalactic medium (IGM) predicts a decreasing temperature of the IGM with decreasing density once hydrogen (and helium) reionisation is complete. Heating the high-redshift, low-density IGM above the temperature expected from photo-heating is difficult, and previous claims of high/rising temperatures in low density regions of the Universe based on the probability density function (PDF) of the opacity in Lyman-$\\alpha$ forest data at $2QSO HE0940-1050 and a novel technique to study the low opacity part of the PDF. We show that there is indeed evidence (at 90% confidence level) that a significant volume fraction of the under-dense regions at $z \\sim 3$ has temperatures as high or higher than those at densities comparable to th...

  10. Ly49 receptors: Innate and adaptive immune paradigms

    Directory of Open Access Journals (Sweden)

    Mir Munir A Rahim

    2014-04-01

    Full Text Available The Ly49 receptors are type II C-type lectin-like membrane glycoproteins encoded by a family of highly polymorphic and polygenic genes within the mouse natural killer gene complex (NKC. This gene family is designated Klra, and includes genes that encode both inhibitory and activating Ly49 receptors in mice. Ly49 receptors recognize class I major histocompatibility complex (MHC-I and MHC-I-like proteins on normal as well as altered cells. Their functional homologs in humans are the killer cell immunoglobulin-like receptors (KIRs, which recognize HLA class I molecules as ligands. Classically, Ly49 receptors are described as being expressed on both the developing and mature natural killer (NK cells. The inhibitory Ly49 receptors are involved in NK cell education, a process in which NK cells acquire function and tolerance towards cells that express ‘self-MHC-I’. On the other hand, the activating Ly49 receptors recognize altered cells expressing activating ligands. New evidence shows a broader Ly49 expression pattern on both innate and adaptive immune cells. Ly49 receptors have been described on multiple NK cell subsets, such as uterine NK (uNK and memory NK cells, as well as NKT cells, dendritic cells (DC, plasmacytoid dendritic cells (pDC, macrophages, neutrophils and cells of the adaptive immune system, such as activated T cells and regulatory CD8+ T cells. In this review we discuss the expression pattern and proposed functions of Ly49 receptors on various immune cells and their contribution to immunity.

  11. The Temporal Behaviour of Lyman-alpha Emission During Solar Flares From SDO/EVE

    CERN Document Server

    Milligan, Ryan O

    2015-01-01

    Despite being the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Lyman-alpha (Ly$\\alpha$) emission during solar flares in recent years. The few examples that do exist, however, have shown Ly$\\alpha$ emission to be a substantial radiator of the total energy budget of solar flares (on the order of 10%). It is also a known driver of fluctuations in earth's ionosphere. The EUV Variability Experiment (EVE) onboard the Solar Dynamics Observatory now provides broadband, photometric Ly$\\alpha$ data at 10 s cadence, and has observed scores of solar flares in the 5 years since it was launched. However, the time profiles appear to display a rise time of tens of minutes around the time of the flare onset. This is in stark contrast to the rapid, impulsive increase observed in other intrinsically chromospheric features (H$\\alpha$, Ly$\\beta$, LyC, C III, etc.). Furthermore, the Ly$\\alpha$ emission peaks around the time of the peak of thermal soft X-ray e...

  12. Lyman Alpha and MgII as Probes of Galaxies and their Environments

    CERN Document Server

    Barnes, Luke A; Kacprzak, Glenn G

    2014-01-01

    Ly{\\alpha} emission, Ly{\\alpha} absorption and MgII absorption are powerful tracers of neutral hydrogen. Hydrogen is the most abundant element in the universe and plays a central role in galaxy formation via gas accretion and outflows, as well as being the precursor to molecular clouds, the sites of star formation. Since 21cm emission from neutral hydrogen can only be directly observed in the local universe, we rely on Ly{\\alpha} emission, and Ly{\\alpha} and MgII absorption to probe the physics that drives galaxy evolution at higher redshifts. Furthermore, these tracers are sensitive to a range of hydrogen densities that cover the interstellar medium, the circumgalactic medium and the intergalactic medium, providing an invaluable means of studying gas physics in regimes where it is poorly understood. At high redshift, Ly{\\alpha} emission line searches have discovered thousands of star-forming galaxies out to z = 7. The large Ly{\\alpha} scattering cross-section makes observations of this line sensitive to even...

  13. Extended Lyman alpha haloes around individual high-redshift galaxies revealed by MUSE

    CERN Document Server

    Wisotzki, L; Blaizot, J; Brinchmann, J; Herenz, E C; Schaye, J; Bouché, N; Cantalupo, S; Contini, T; Carollo, C M; Caruana, J; Courbot, J -B; Emsellem, E; Kamann, S; Kerutt, J; Leclercq, F; Lilly, S J; Patrício, V; Sandin, C; Steinmetz, M; Straka, L A; Urrutia, T; Verhamme, A; Weilbacher, P M; Wendt, M

    2015-01-01

    We report the detection of extended Ly alpha emission around individual star-forming galaxies at redshifts z = 3-6 in an ultradeep exposure of the Hubble Deep Field South obtained with MUSE on the ESO-VLT. The data reach a limiting surface brightness (1sigma) of ~1 x 10^-19 erg s^-1 cm^-2 arcsec^-2 in azimuthally averaged radial profiles, an order of magnitude improvement over previous narrowband imaging. Our sample consists of 26 spectroscopically confirmed Ly alpha-emitting, but mostly continuum-faint (m_AB >~ 27) galaxies. In most objects the Ly alpha emission is considerably more extended than the UV continuum light. While 5 of the faintest galaxies in the sample show no significantly detected Ly alpha haloes, the derived upper limits suggest that this is just due to insufficient S/N. Ly alpha haloes therefore appear to be (nearly) ubiquitous even for low-mass (~10^8-10^9 M_sun) star-forming galaxies at z>3. We decompose the Ly alpha emission of each object into a compact `continuum-like' and an extended ...

  14. H-alpha features with hot onsets III. Fibrils in Lyman-alpha and with ALMA

    CERN Document Server

    Rutten, Robert J

    2016-01-01

    In H-alpha most of the solar surface is covered by a dense canopy of long opaque fibrils, but predictions for quiet-Sun observations with ALMA have ignored this fact. Comparison with Ly-alpha suggests that the large opacity of H-alpha fibrils is caused by hot precursor events. Application of a recipe that assumes momentary Saha-Boltzmann extinction during their hot onset to millimeter wavelengths suggests that ALMA will observe the H-alpha fibril canopy, not acoustic shocks underneath, and will yield data more interesting than if this canopy were transparent.

  15. Refractive Focusing by Interstellar Clouds and the Rapid Polarization Angle Swing in QSO 1150+812

    Institute of Scientific and Technical Information of China (English)

    Shan-Jie Qian; J.A. Zensus; T. P. Krichbaum; Xi-Zhen Zhang; L. Fuhrmann; G. Cimò; A. Kraus; T. Beckert; S. Britzen; A. Witzel

    2006-01-01

    A very rapid polarization position angle swing of ~ 180° (with a time scale of ~6 hours) observed at 2cm in QSO 1150+812 (z = 1.25) was reported by Kochenov & Gabuzda. This very rare event is difficult to explain. We found a possible interpretation in the framework of a source model consisting of three polarized components, in which two compact polarized components are nearly simultaneously occulted by an interstellar cloud, with consequent focusing-defocusing effects. A specific plasma-lens model is proposed which can reasonably fit the polarized flux density curve with results derived for the two lensed components. Some physical parameters of the plasma-lens and the source components are estimated. The two compact polarized components are estimated to have brightness temperatures of ~ 6 × 1012 K.Thus a bulk relativistic motion with a Lorentz factor less than 10 is required to meet the inverse-Compton limit.

  16. The TESIS Project: Are Type 2 QSO Hidden in X-Ray Emitting EROs?

    Science.gov (United States)

    Severgnini, P.; Della Ceca, R.; Braito, V.; Saracco, P.; Longhetti, M.; Bender, R.; Drory, N.; Feulner, G.; Hopp, U.; Mannucci, F.; Maraston, C.

    X-ray selected EROs are, on average, the hardest X-ray sources in medium and deep X-ray fields. This coupled with their extremely red colors (R-K > 5) suggest that they represent one of the most promising population where looking for high-luminosity (LX > 1044 erg s-1) and X-ray obscured (NH > 1022 cm-2) type2 AGNs, the so called QSO2 (e.g., [5]; [4]; Mignoli et al. submitted to A&A). These latter are predicted in large density by the synthesis model of the Cosmic X-ray background [9] even if only few observational evidences have been found so far (e.g., [1] and references therein; Caccianiga et al. A&A accepted).

  17. VizieR Online Data Catalog: A Homogeneous Bright QSO Survey (Cristiani+, 1995)

    Science.gov (United States)

    Cristiani, S.; La Franca, F.; Andreani, P.; Gemmo, A.; Goldschmidt, P.; Miller, L.; Vio, R.; Barbieri, C.; Bodini, L.; Iovino, A.; Lazzarin, M.; Clowes, R.; MacGillivray, H.; Gouiffes, Ch.; Lissandrini, C.; Savage, A.

    1995-05-01

    This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range 15QSO counts are determined in the magnitude range 17

  18. Variable X-Ray Absorption in the Mini-BAL QSO PG 1126-041

    Science.gov (United States)

    Giustini, M.; Cappi, M.; Chartas, G.; Dadina, M.; Eracleous, M.; Ponti, G.; Proga, D.; Tombesi, F.; Vignali, C.; Palumbo, G. G. C.

    2011-01-01

    Context. X-ray studies of AGN with powerful nuclear winds are important to constrain the physics of the inner accretion/ejection flow around SMBH, and to understand the impact of such winds on the AGN environment. Aims. Our main scientific goal is to constrain the properties of a variable outflowing absorber that is thought to be launched near the SMBH of the mini-BAL QSO PG 1126-041 using a multi-epoch observational campaign performed with XMM-Newton. Methods. We performed temporally resolved X-ray spectroscopy and simultaneous UV and X-ray photometry on the most complete set of observations and on the deepest X-ray exposure of a mini-BAL QSO to date. Results. We found complex X-ray spectral variability on time scales of both months and hours, best reproduced by means of variable massive ionized absorbers along the line of sight. As a consequence, the observed optical-to-X-ray spectral index is found to be variable with time. In the highest signal-to-noise observation we detected highly ionized X-ray absorbing material outflowing much faster (u(sub X) approx. 16 500 km/s) than the UV absorbing one (u(sub uv) approx. 5,000 km/s). This highly ionized absorber is found to be variable on very short (a few kiloseconds) time scales. Conclusions. Our findings are qualitatively consistent with line driven accretion disk winds scenarios. Our observations have opened the time-resolved X-ray spectral analysis field for mini-BAL QSOs; only with future deep studies will we be able to map the dynamics of the inner flow and understand the physics of AGN winds and their impact on the environment.

  19. The Lyman-$\\alpha$ signature of the first galaxies

    CERN Document Server

    Smith, Aaron; Bromm, Volker; Milosavljević, Miloš

    2014-01-01

    We present the Cosmic Lyman-$\\alpha$ Transfer code (COLT), a new massively parallel Monte-Carlo radiative transfer code, to simulate Lyman-$\\alpha$ (Ly$\\alpha$) resonant scattering through neutral hydrogen as a probe of the first galaxies. We explore the interaction of centrally produced Ly$\\alpha$ radiation with the host galactic environment. The Ly$\\alpha$ photons emitted from the luminous starburst region escape with characteristic features in the line profile depending on the density distribution, ionization structure, and bulk velocity fields. For example, the presence of anisotropic ionization exhibits a tall peak close to line centre with a skewed tail that drops off gradually. Furthermore, moderate (~10 km/s) outflow produces an amplified peak redward of line centre. Idealized models of first galaxies explore the effect of mass, anisotropic H II regions, and radiation pressure driven winds on Ly$\\alpha$ observables. We employ mesh refinement to resolve critical structures. We also post-process an ab i...

  20. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Adamo, Angela [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schaerer, Daniel [Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse (France); Verhamme, Anne; Orlitová, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Otí-Floranes, Héctor [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M.; Pardy, Stephen [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Atek, Hakim [Laboratoire dAstrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095, CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Herenz, E. Christian, E-mail: matthew@astro.su.se [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

    2014-02-10

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f{sub esc}{sup Lyα} of 80%; such objects have not previously been reported at low-z.

  1. Photometric followup investigations on LAMOST survey target Ly And

    Science.gov (United States)

    Lu, Hong-peng; Zhang, Li-yun; Han, Xianming L.; Pi, Qing-feng; Wang, Dai-mei

    2017-02-01

    We present a low-dispersion spectrum and two sets of CCD photometric light curves of the eclipsing binary LY And for the first time. The spectrum of LY And was classified as G2. We derived an updated ephemeris based on all previously available and our newly acquired minimum light times. Our analyses of LY And light curve minimum times reveals that the differences between calculated and observed minimum times for LY And can be represented by an upward parabolic curve, which means its orbital period is increasing with a rate of 1.88 (± 0.13) × 10-7 days/year. This increase in orbital period may be interpreted as mass transfer from the primary component to the secondary component, with a rate of dM1/dt = -4.54 × 10-8M⊙/year. By analyzing our CCD photometric light curves obtained in 2015, we obtained its photometric solution with the Wilson-Devinney program. This photometric solution also fits very well our light curves obtained in 2014. Our photometric solution shows that LY And is a contact eclipsing binary and its contact factor is f = (17.8 ± 1.9)%. Furthermore, both our spectroscopic and photometric data show no obvious chromospheric activity of LY And.

  2. The environments of Ly$\\alpha$ blobs I: Wide-field Ly$\\alpha$ imaging of TN J1338-1942, a powerful radio galaxy at $z\\simeq 4.1$ associated with a giant Ly$\\alpha$ nebula

    CERN Document Server

    Saito, Tomoki; Lacey, Cedric G; Smail, Ian; Orsi, Alvaro; Baugh, Carlton M; Inoue, Akio K; Tanaka, Ichi; Yamada, Toru; Ohta, Kouji; De Breuck, Carlos; Kodama, Tadayuki; Taniguchi, Yoshiaki

    2014-01-01

    We present wide-field Lya imaging observations of the field around TN J1338-1942, a powerful radio galaxy associated with an extended Lya nebula (>100 kpc) at z=4.11, with Subaru Prime-focus Camera to probe the environment of the radio galaxy. We used a sample of Lya emitters (LAEs) down to the Lya luminosity of $\\log(L_{\\rm Lya}\\rm [erg\\, s^{-1}])\\sim 42.8$ to measure the galaxy density of this field, calibrating by direct comparison with a control sample in a blank field taken with the same instrument. We found that the radio galaxy resides in a region with a peak overdensity of $\\delta_{\\rm LAE}=3.1\\pm 0.5$, after being smoothed on $8\\, h^{-1}$ Mpc scales on the sky and $160\\, h^{-1}$ Mpc along the line of sight (both in comoving coordinates). Adjacent to this overdense region, we found a highly underdense region where virtually no LAEs are detected. We used a semi-analytical model of LAEs derived from the Millennium Simulation to compare our results with theoretical predictions. This comparison suggests t...

  3. Mapping the low-surface brightness Universe in the UV band with Lyα emission from IGM filaments

    Science.gov (United States)

    Silva, Marta B.; Kooistra, Robin; Zaroubi, Saleem

    2016-10-01

    A large fraction of the baryonic matter in the Universe is located in filaments in the intergalactic medium (IGM). However, the low surface brightness of these filaments has not yet allowed their direct detection except in very special regions in the circum-galactic medium. Here we simulate the intensity and spatial fluctuations in Lyman alpha (Lyα) emission from filaments in the IGM and discuss the prospects for the next generation of space-based instruments to detect the low-surface brightness Universe at ultraviolet (UV) wavelengths. Starting with a high-resolution N-body simulation, we obtain the dark matter density fluctuations and associate baryons with the dark matter particles assuming that they follow the same spatial distribution. The IGM thermal and ionization state is set by a model of the UV background and by the relevant cooling processes for a hydrogen and helium gas. The Lyα emissivity is then estimated, taking into account recombination and collisional excitation processes. We find that the detection of these filaments through their Lyα emission is well in the reach of the next generation of UV space-based instruments and so it should be achieved in the next decade. The density field is populated with halos and galaxies and their Lyα emission is estimated. Galaxies are treated as foregrounds and so we discuss methods to reduce their contamination from observational maps. Finally, we estimate the UV continuum background as a function of the redshift of the Lyα emission line and discuss how this continuum can affect observations.

  4. Exploration of the Radio-Loud/Radio Quiet Dichotomy for QSO: Using Radio Morphology and 4D Eigenvector 1

    Science.gov (United States)

    Zamfir, Sebastian; Sulentic, J. W.; Marziani, P.; Dultzin, D.

    2007-12-01

    The reality of a RL/RQ Dichotomy for QSO remains an open problem. Recent studies not only provide us with contradictory results, but also display the confusion of comparing conclusions drawn on the basis of different views on "what means radio-loud"? We propose a definition of radio loudness based on three criteria (simultaneously applied): radio morphology, radio luminosity and radio-optical flux density ratio. Fanaroff-Riley II radio sources (FRIIs) are assumed to be the parent population of RL quasars, while the core dominated RL quasars are assumed to be preferentially aligned FRIIs. Orientation-unification then suggests the RQ-RL boundary is set by the least radio luminous FRII and by the lowest radio-optical ratio for an FRII. We also consider RL and RQ quasars in the context of a 4D Eigenvector 1 (4DE1) Parameter Space that is defined independently of any radio measure. Using Sloan Digital Sky Survey (SDSS) spectroscopic data for 400+ QSO (z<0.7 and brighter than psf g =17.5), coupled with FIRST and NVSS radio surveys (1.4GHz), we show that classical RL sources distribute very differently from the RQ majority of QSO.

  5. Evidence of Primordial Clustering around the QSO SDSS J1030+0524 at z=6.28

    Science.gov (United States)

    Stiavelli, M.; Djorgovski, S. G.; Pavlovsky, C.; Scarlata, C.; Stern, D.; Mahabal, A.; Thompson, D.; Dickinson, M.; Panagia, N.; Meylan, G.

    2005-03-01

    We present tentative evidence of primordial clustering, manifested as an excess of color-selected objects in the field of the QSO SDSS J1030+0524 at redshift z=6.28. We have selected objects red in i775-z850 on the basis of Hubble Space Telescope Advanced Camera for Surveys imaging of a field centered on the QSO. Compared to data at comparable depth obtained by the Great Observatories Origins Deep Survey, we find an excess of objects with i775-z850>=1.5 in the QSO field. The significance of the detection is estimated to be ~97% on the basis of the counts alone and increases to 99.4% if one takes into account the color distribution. If confirmed, this would represent the highest redshift example of galaxy clustering and would have implications on models for the growth of structure. Bias-driven clustering of first luminous objects forming in the highest peaks of the primordial density field is expected in most models of early structure formation. The redshift of one of the candidates has been found to be z=5.970 by our spectroscopy with the Keck I Low Resolution Imaging Spectrometer, confirming the validity of our color selection. Based, in part, on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

  6. Integral Field Spectroscopy of Massive, Kiloparsec-Scale Outflows in the Infrared-Luminous QSO Mrk 231

    CERN Document Server

    Rupke, David S N; 10.1088/2041-8205/729/2/L27

    2011-01-01

    The quasi-stellar object (QSO)/merger Mrk 231 is arguably the nearest and best laboratory for studying QSO feedback. It hosts several outflows, including broad-line winds, radio jets, and a poorly-understood kpc scale outflow. In this Letter, we present integral field spectroscopy from the Gemini telescope that represents the first unambiguous detection of a wide-angle, kpc scale outflow from a powerful QSO. Using neutral gas absorption, we show that the nuclear region hosts an outflow with blueshifted velocities reaching 1100 km/s, extending 2-3 kpc from the nucleus in all directions in the plane of the sky. A radio jet impacts the outflow north of the nucleus, accelerating it to even higher velocities (up to 1400 km/s). Finally, 3.5 kpc south of the nucleus, star formation is simultaneously powering an outflow that reaches more modest velocities of only 570 km/s. Blueshifted ionized gas is also detected around the nucleus at lower velocities and smaller scales. The mass and energy flux from the outflow are ...

  7. Variability of broad absorption lines in a QSO SDSS J022844.09+000217.0 on multi-year timescales

    CERN Document Server

    He, Zhi-Cheng; Jiang, Xiao-Lei; Wang, Yue-Feng

    2015-01-01

    The variability of the broad absorption lines is investigated for a broad absorption line (BAL) QSO, SDSS J022844.09+000217.0 (z = 2.719), with 18 SDSS/BOSS spectra covering 4128 days in the observed frame. With the ratio of the rms spectrum to the mean spectrum, the relative flux change of the BAL-trough is larger than that of the emission lines and the continuum. Fitting the power-law continuum and the emission line profiles of \\civ $\\lambda$1549 and \\siiv$\\lambda$1399, we calculate the equivalent width (EW) for different epochs, as well as the continuum luminosity and the spectral index. It is found that there is a strong correlation between the BAL-trough EW and the spectral index, and a weak negative correlation between the BAL-trough EW and the continuum luminosity. The strong correlation between the BAL-trough EW and the spectral index for this one QSO suggests that dust is intrinsic to outflows. The weak correlation between the BAL variability and the continuum luminosity for this one QSO implies that...

  8. Discovery of a Jet-Like Structure at the High Redshift QSO CXOMP J084128.3+131107

    CERN Document Server

    Schwartz, D A; Birkinshaw, M; Karovska, M; Aldcroft, T L; Barkhouse, W; Green, P; Kim, D W; Wilkes, B J; Worrall, D M

    2004-01-01

    The Chandra Multiwavelength Project (ChaMP) has discovered a jet-like structure associated with a newly recognized QSO at redshift z=1.866. The system was 9.4 arcmin off-axis during an observation of 3C 207. Although significantly distorted by the mirror PSF, we use both a raytrace and a nearby bright point source to show that the X-ray image must arise from some combination of point and extended sources, or else from a minimum of three distinct point sources. We favor the former situation, as three unrelated sources would have a small probability of occurring by chance in such a close alignment. We show that interpretation as a jet emitting X-rays via inverse Compton (IC) scattering on the cosmic microwave background (CMB) is plausible. This would be a surprising and unique discovery of a radio-quiet QSO with an X-ray jet, since we have obtained upper limits of 100 microJy on the QSO emission at 8.46 GHz, and limits of 200 microJy for emission from the putative jet.

  9. Broad Balmer Absorption Line Variability: Evidence of Gas Transverse Motion in the QSO SDSS J125942.80+121312.6

    CERN Document Server

    Shi, Xiheng; Shu, Xinwen; Zhang, Shaohua; Ji, Tuo; Pan, Xiang; Sun, Luming; Zhao, Wen; Hao, Lei

    2016-01-01

    We report on the discovery of broad Balmer absorption lines variability in the QSO SDSS J125942.80+121312.6, based on the optical and near-infrared spectra taken from the SDSS-I, SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), and TripleSpec observations over a timescale of 5.8 years in the QSO's rest-frame. The blueshifted absorption profile of H$\\beta$ shows a variation of more than 5$\\sigma$ at a high velocity portion ($>3000\\ \\mathrm{km\\ s}^{-1}$) of the trough. We perform a detailed analysis for the physical conditions of the absorber using Balmer lines as well as metastable He I and optical Fe II absorptions ($\\lambda 4233$ from b$^4$P$_{5/2}$ level and $\\lambda 5169$ from a$^6$S$_{5/2}$) at the same velocity. These Fe II lines are identified in the QSO spectra for the first time. According to the photoionization simulations, we estimate a gas density of $n(\\mathrm{H})\\approx 10^{9.1}\\ \\mathrm{cm}^{-3}$ and a column density of $N_{\\mathrm{col}}(\\mathrm{H})\\approx 10^{23}\\ \\mathrm{cm}^{-2}$ for ...

  10. Signatures of positive selection in LY96 gene in vertebrates

    Indian Academy of Sciences (India)

    Tonghai Dou; Maobin Fu; Yixia Wang; Yang Zhao; Zhengshi Wang; Zhengqian Bian; Yan Zhou

    2013-12-01

    As a secreted glycoprotein that binds to the extracellular domain of Toll-like receptor 4 (TLR4), Lymphocyte Antigen 96 (LY96), also called myeloid differentiation 2 (MD2), is required for the activation of TLR4 by lipopolysaccharide (LPS) and plays an important role in innate immunity, which is the first line of defence against microbial infections. Previous studies have proposed that mammalian toll-like receptors (TLRs) have evolved under diversifying selection due to their role in pathogen detection. Given the fact that LY96 is highly functionally linked to TLR4, it would be interesting to test whether LY96 is under the intense pressure of natural selection. To investigate the natural selection hypothesis, we compared the coding sequences from 13 vertebrates and evaluated the molecular evolution of LY96 gene in these species. Result shows that natural selection at exon 4 has indeed played a role in shaping the function of LY96 in the course of evolution. In addition to the study of Nakajima, we found the two branch nodes with Ka/Ks ratios greater than 1: the one leading to cow and pig and the other to rabbit and the primates.

  11. Observational challenges in Lyα intensity mapping

    Science.gov (United States)

    Comaschi, P.; Yue, B.; Ferrara, A.

    2016-12-01

    Intensity mapping (IM) is sensitive to the cumulative line emission of galaxies. As such, it represents a promising technique for statistical studies of galaxies fainter than the limiting magnitude of traditional galaxy surveys. The strong hydrogen Lyα line is the primary target for such an experiment, as its intensity is linked to star formation activity and the physical state of the interstellar and intergalactic medium. However, to extract the meaningful information, one has to solve the confusion problems caused by interloping lines from foreground galaxies. We discuss here the challenges for a Lyα IM experiment targeting z > 4 sources. We find that the Lyα power spectrum can be, in principle, easily (marginally) obtained with a 40 cm space telescope in a few days of observing time up to z ≲ 8 (z ˜ 10) assuming that the interloping lines (e.g. Hα, [O II], [O III] lines) can be efficiently removed. We show that interlopers can be removed by using an ancillary photometric galaxy survey with limiting AB mag ˜26 in the near-infrared bands (Y, J, H, or K). This would enable detection of the Lyα signal from 5 sources. However, if a [C II] IM experiment is feasible, by cross-correlating the Lyα with the [C II] signal, the required depth of the galaxy survey can be decreased to AB mag ˜24. This would bring the detection at the reach of future facilities working in close synergy.

  12. DISCOVERY OF A DAMPED Lyα ABSORBER AT z = 3.3 ALONG A GALAXY SIGHT-LINE IN THE SSA22 FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Mawatari, K.; Inoue, A. K. [College of General Education, Osaka Sangyo University, 3-1-1, Nakagaito, Daito, Osaka, 574-8530 (Japan); Kousai, K.; Hayashino, T. [Research Center for Neutrino Science, General School of Science, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Cooke, R.; Prochaska, J. X. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Yamada, T. [Astronomical Institute, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578 (Japan); Matsuda, Y., E-mail: mawatari@las.osaka-sandai.ac.jp [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)

    2016-02-01

    Using galaxies as background light sources to map the Lyα absorption lines is a novel approach to study Damped Lyα Absorbers (DLAs). We report the discovery of an intervening z = 3.335 ± 0.007 DLA along a galaxy sight-line identified among 80 Lyman Break Galaxy (LBG) spectra obtained with our Very Large Telescope/Visible Multi-Object Spectrograph survey in the SSA22 field. The measured DLA neutral hydrogen (H i) column density is log(N{sub H} {sub i}/cm{sup −2}) = 21.68 ± 0.17. The DLA covering fraction over the extended background LBG is >70% (2σ), yielding a conservative constraint on the DLA area of ≳1 kpc{sup 2}. Our search for a counterpart galaxy hosting this DLA concludes that there is no counterpart galaxy with star formation rate larger than a few M{sub ⊙} yr{sup −1}, ruling out an unobscured violent star formation in the DLA gas cloud. We also rule out the possibility that the host galaxy of the DLA is a passive galaxy with M{sub *} ≳ 5 × 10{sup 10}M{sub ⊙} or a heavily dust-obscured galaxy with E(B − V) ≳ 2. The DLA may coincide with a large-scale overdensity of the spectroscopic LBGs. The occurrence rate of the DLA is compatible with that of DLAs found in QSO sight-lines.

  13. Alpha Thalassemia

    Science.gov (United States)

    Alpha Thalassemia Physicians often mistake alpha thalassemia trait for iron deficiency anemia and incorrectly prescribe iron supplements that have no effect 1 on the anemia. αα αα Normal alpha ...

  14. PACS-Herschel FIR detections of Lyman-alpha emitters at 2.0

    CERN Document Server

    Oteo, I; García, A M Pérez; Cepa, J; Ederoclite, A; Sánchez-Portal, M; Pintos-Castro, I; Pérez-Martínez, R; Altieri, B; Andreani, P; Aussel, H; Berta, S; Cimatti, A; Daddi, E; Elbaz, D; Schreiber, N Förster; Genzel, R; Lutz, D; Magnelli, B; Maiolino, R; Poglitsch, A; Popesso, P; Pozzi, F; Sturm, E; Tacconi, L; Valtchanov, I

    2012-01-01

    In this work we analyze the physical properties of a sample of 56 spectroscopically selected star-forming (SF) Ly$\\alpha$ emitting galaxies at 2.0$\\lesssim$z$\\lesssim$3.5 using both a spectral energy distribution (SED) fitting procedure from rest-frame UV to mid-IR and direct 160$\\mu$m observations taken with the Photodetector Array Camera & Spectrometer (PACS) instrument onboard \\emph{Herschel Space Observatory}. We define LAEs as those Ly$\\alpha$ emitting galaxies whose rest-frame Ly$\\alpha$ equivalent widths (Ly$\\alpha$ EW$_{rest-frame}$) are above 20\\AA, the typical threshold in narrow-band searches. Ly$\\alpha$ emitting galaxies with Ly$\\alpha$ EW$_{rest-frame}$ are called non-LAEs. As a result of an individual SED fitting for each object, we find that the studied sample of LAEs contains galaxies with ages mostly below 100Myr and a wide variety of dust attenuations, SFRs, and stellar masses. The heterogeneity in the physical properties is also seen in the morphology, ranging from bulge-like galaxies t...

  15. Constraining the Lyα escape fraction with far-infrared observations of Lyα emitters

    Energy Technology Data Exchange (ETDEWEB)

    Wardlow, Julie L.; Calanog, J.; Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Malhotra, S.; Zheng, Z.; Rhoads, J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Finkelstein, S. [The University of Texas at Austin, Austin, TX 78712 (United States); Bock, J.; Bridge, C. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Ciardullo, R.; Gronwall, C. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Farrah, D. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Gawiser, E. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Heinis, S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Ibar, E. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Ivison, R. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Marsden, G. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Oliver, S. J. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Riechers, D., E-mail: jwardlow@dark-cosmology.dk [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); and others

    2014-05-20

    We study the far-infrared properties of 498 Lyα emitters (LAEs) at z = 2.8, 3.1, and 4.5 in the Extended Chandra Deep Field-South, using 250, 350, and 500 μm data from the Herschel Multi-tiered Extragalactic Survey and 870 μm data from the LABOCA ECDFS Submillimeter Survey. None of the 126, 280, or 92 LAEs at z = 2.8, 3.1, and 4.5, respectively, are individually detected in the far-infrared data. We use stacking to probe the average emission to deeper flux limits, reaching 1σ depths of ∼0.1 to 0.4 mJy. The LAEs are also undetected at ≥3σ in the stacks, although a 2.5σ signal is observed at 870 μm for the z = 2.8 sources. We consider a wide range of far-infrared spectral energy distributions (SEDs), including an M82 and an Sd galaxy template, to determine upper limits on the far-infrared luminosities and far-infrared-derived star formation rates of the LAEs. These star formation rates are then combined with those inferred from the Lyα and UV emission to determine lower limits on the LAEs' Lyα escape fraction (f {sub esc}(Lyα)). For the Sd SED template, the inferred LAEs f {sub esc}(Lyα) are ≳ 30% (1σ) at z = 2.8, 3.1, and 4.5, which are all significantly higher than the global f {sub esc}(Lyα) at these redshifts. Thus, if the LAEs f {sub esc}(Lyα) follows the global evolution, then they have warmer far-infrared SEDs than the Sd galaxy template. The average and M82 SEDs produce lower limits on the LAE f {sub esc}(Lyα) of ∼10%-20% (1σ), all of which are slightly higher than the global evolution of f {sub esc}(Lyα), but consistent with it at the 2σ-3σ level.

  16. Redshift distribution of Lyα lines and metal systems

    Science.gov (United States)

    Demiański, M.; Doroshkevich, A. G.; Turchaninov, V.

    2000-11-01

    The observed redshift distribution of Lyα lines and metal systems is examined in order to discriminate and to trace the evolution of structure elements observed in the galaxy distribution, at small redshifts, and to test the theoretical description of structure evolution. We show that the expected evolution of a filamentary component of structure describes quite well the redshift distribution of metal systems and stronger Lyα lines with log(NHi)>=14, at z<=3. The redshift distribution of weaker Lyα lines can be attributed to the population of poorer structure elements (Zel'dovich pancakes), which were formed at high redshifts from the invisible dark matter and non-luminous baryonic matter, and which at lower redshifts are mainly merged and dispersed.

  17. A Multiply-Imaged z $\\sim$ 6.3 Lyman Alpha Emitter candidate behind Abell 2261

    CERN Document Server

    Rydberg, Claes-Erik; Zackrisson, Erik; Melinder, Jens; Whalen, Daniel J; Klessen, Ralf S; Gonzalez, Juan; Östlin, Göran; Carollo, Daniela

    2016-01-01

    While the Lyman-$\\alpha$ ($\\mathrm{Ly}\\alpha$) emission line serves as an important tool in the study of galaxies at $z\\lesssim 6$, finding Ly$\\alpha$ emitters (LAE) at significantly higher redshifts has been more challenging, probably because of the increasing neutrality of the intergalactic medium above $z\\sim6$. Galaxies with extremely high rest-frame Ly$\\alpha$ equivalent widths, EW(Ly$\\alpha$) $\\gtrsim 150$ \\AA{}, at $z>6$ are good candidates for Ly$\\alpha$ follow-up observations, and can stand out in multiband imaging surveys because of their unusual colors. We have conducted a photometric search for such objects in the Cluster Lensing And Supernova survey with Hubble (CLASH), and report here the identification of three likely gravitationally-lensed images of a single LAE candidate at $z\\sim6.3$, behind the galaxy cluster Abell 2261($z = 0.225$). In the process, we also measured with Keck/MOSFIRE the first spectroscopic redshift of a multiply-imaged galaxy behind Abell 2261, at $z = 3.337$. This allows ...

  18. Clinical and immunohistochemical performance of lyophilized platelet-rich fibrin (Ly-PRF) on tissue regeneration.

    Science.gov (United States)

    Zhang, Jianming; Qi, Xingying; Luo, Xiaoding; Li, Dan; Wang, Haorong; Li, Ting

    2017-06-01

    Platelet-rich fibrin (PRF) has been widely used in oral implantology and other fields, but benefits of the fresh PRF (FPRF (fresh platelet-rich fibrin)) were consequently limited because of its short-term application. Thus, a protocol for the combination of PRF and lyophilization comes up in the present study to address the issue of PRF storage and delayed clinical application, which has little been reported in this field at home and abroad by now. The aim of the present study was to evaluate the applicability of lyophilized platelet-rich fibrin (Ly-PRF) used as the scaffold material for craniofacial tissue regeneration and to compare its biochemical properties with commonly used fresh PRF. Two volunteers with both genders were selected as the source of PRF and Ly-PRF samples. Macro- and micro-scopic appearance evaluation as well as immunohistochemical comparison were performed on PRF samples before and after freeze-drying at -196°C. The second experimental phase was to observe clinical performance when fresh and lyophilized PRF were applied in guided bone regeneration (GBR) operations in 39 patients losing teeth in the anterior maxillary region who required an oral implantation followed by labial bone grafting. The conventional histological and transmission electron microscopy images showed the microstructure of Ly-PRF, which resembled a mesh containing apparently irregularly shaped platelets with less alpha-granule than fresh PRF in micro and a translucent membrane with less elasticity than fresh PRF in macro. Simultaneous immunohistological staining results showed positive expression of PDGF-BB, IL-1, IL-4, TNF, TGF-β1 in both fresh and lyophilized PRF, while the expression of PDGF-BB, IL-1, TNF, TGF-β1 has no statistical difference between them (P > .05) but that of IL-4 in Ly-PRF is statistically higher than in fresh PRF (P  .05). This study strongly supports that lyophilization at -196°C does not largely influence the expression of bioactive

  19. A New Population of High-z, Dusty Lyα Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

    Science.gov (United States)

    Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger L.; Jarrett, Tom; Lonsdale, Carol; Stanford, Spencer A.; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L.; Wu, Jingwen

    2013-06-01

    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 blobs" (LABs). The objects have a surface density of only ~0.1 deg-2, making them rare enough that they have been largely missed in deep, small area surveys. We measured spectroscopic redshifts for 92 of these galaxies, and find that the LAEs (LABs) have a median redshift of 2.3 (2.5). The WISE photometry coupled with data from Herschel (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) reveals that these galaxies are in the Hyper Luminous IR galaxy regime (L IR >~ 1013-1014 L ⊙) and have warm colors. They are typically more luminous and warmer than other dusty, z ~ 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Lyα, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy.

  20. Release Behaviour of Shock Loaded LY12 Aluminium Alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Min; DAI Lan-Hong; SHEN Le-Tian

    2005-01-01

    @@ By making use of a light gas gun, a specially designed target is impacted by the LY12 flyer, and the pressure is taken in the range of 0.6-3 GPa. Based on the stress profiles measured in the buffer materials by manganese gauges, the Hugoniot curve and release curves of LY12 aluminium alloy are obtained. Meanwhile, the release curves from different initial shocked states are described in both the pressure-particle velocity plane and the pressure-specific volume plane.

  1. For-LySa: UML for Authentication Analysis

    DEFF Research Database (Denmark)

    Buchholtz, Mikael; Montangero, Carlo; Perrone, Lara;

    2005-01-01

    The DEGAS project aims at enriching standard UML-centred development environments in such a way that the developers of global applications can exploit automated formal analyses with minimal overhead. In this paper, we present For-LySa, an instantiation of the DEGAS approach for authentication...... analysis, which exploits an existing analysis tool developed for the process calculus LySa. We discuss what information is needed for the analysis, and how to build the UML model of an authentication protocol in such a way that the needed information can be extracted from the model. We then present our...

  2. Statistical Cluster-QSO Weak Lensing in the Sloan Digital Sky Survey

    Institute of Scientific and Technical Information of China (English)

    Zhong-Lue Wen; Yan-Bin Yang; Xu Zhou; Qi-Rong Yuan; Jun Ma

    2006-01-01

    We investigate the cross-correlation between galaxy clusters and QSOs using Sloan Digital Sky Survey (SDSS) DR4 ~ 5000 deg2 data. With photometric redshifts of galaxies,we select galaxy clusters based on the local projected densities of LRGs brighter than Mr'=-22. The QSOs are from the mainsample of SDSS QSO spectroscopic survey to i' = 19. A significant positive correlation is found between the clusters and QSOs. Under the assumption that the signal is caused by gravitational lensing, we fit the signal with singular isothermal sphere (SIS) model and NFW profile halo model. The velocity dispersion σv = 766 km s-1 is derived for the best-fit of SIS model. Best-fit for the NFW model requires the dark matter halo mass within 1.5 h-1 Mpc to be 4.6 × 1014 h-1 M⊙. The mass parameter Ωcl of the cluster sample is deduced as 0.077 with the SIS model and 0.083 with the NFW model. Our results of Ωcl are smaller than those given by Croom & Shanks and by Myers et al.

  3. A low-luminosity type-1 QSO sample: II. Overluminous host spheroidals or undermassive black holes?

    CERN Document Server

    Busch, Gerold; Valencia-S., Mónica; Moser, Lydia; Fischer, Sebastian; Eckart, Andreas; Scharwächter, Julia; Gadotti, Dimitri A; Wisotzki, Lutz

    2013-01-01

    Recognizing the properties of the host galaxies of quasi-stellar objects (QSOs) is essential to understand the suspected coevolution of central supermassive black holes (BHs) and their host galaxies. We selected a subsample of the Hamburg/ESO survey for bright UV-excess QSOs, containing only the 99 nearest QSOs with redshift z<=0.06, that are close enough to allow detailed structural analysis. From this "low-luminosity type-1 QSO sample", we observed 20 galaxies and performed aperture photometry and bulge-disk-bar-AGN-decomposition with BUDDA on near-infrared J, H, K band images. From the photometric decomposition of these 20 objects and visual inspection of images of another 26, we find that ~50% of the hosts are disk galaxies and most of them (86%) are barred. Stellar masses, calculated from parametric models based on inactive galaxy colors, range from 2x10^9 M_sun to 2x10^11 M_sun. Black hole masses measured from single epoch spectroscopy range from 1x10^6 M_sun to 5x10^8 M_sun. In comparison to higher ...

  4. The Kinematic Connection Between QSO-Absorbing Gas and Galaxies at Intermediate Redshift

    CERN Document Server

    Steidel, C C; Shapley, A E; Churchill, C W; Dickinson, M; Pettini, M

    2002-01-01

    We present complementary data on 5 intermediate redshift (0.44 < z < 0.66) MgII absorbing galaxies, combining high spatial resolution imaging from HST, high--resolution QSO spectroscopy from Keck/HIRES, and galaxy kinematics from intermediate resolution spectroscopy using Keck/LRIS. These data allow a direct comparison of the kinematics of gas at large galactocentric impact parameters with the galaxy kinematics obtained from the faint galaxy spectroscopy. All 5 galaxies appear to be relatively normal spirals, with measured rotation curves yielding circular velocities in the range 100 < v_c < 260 km/s. We find that in 4 of the 5 cases examined, the velocities of all of the Mg II absorption components lie entirely to one side of the galaxy systemic redshift. These observations are consistent with rotation being dominant for the absorbing gas kinematics; however, the total range of velocities observed is inconsistent with simple disk rotation in every case. Simple kinematic models that simultaneously...

  5. High resolution spectroscopy of the three dimensional cosmic web with close QSO groups

    CERN Document Server

    Cappetta, M; Cristiani, S; Saitta, F; Viel, M

    2010-01-01

    We study the three-dimensional distribution of matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydro-dynamical simulations. We present a sample of 15 QSOs, corresponding to 21 baselines of angular separations evenly distributed between ~1 and 14 arcmin, observed with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT). The observed correlation functions of the transmitted flux in the HI Lya forest transverse to and along the line of sight are in agreement, implying that the distortions in redshift space due to peculiar velocities are relatively small and - within the relatively large error bars - not significant. The clustering signal is significant up to velocity separations of ~300 km/s, corresponding to about 5 h^{-1} comoving Mpc. Compatibility at the 2 sigma level has been found both for the Auto- and Cross-correlation functions and for the set of the Cross correlation coefficient...

  6. Coronal properties of the luminous radio-quiet quasar QSO B2202$-$209

    CERN Document Server

    Kammoun, E S; Stern, D; Jun, H D; Graham, M; Celotti, A; Behar, E; Elvis, M; Harrison, F A; Matt, G; Walton, D J

    2016-01-01

    We present an analysis of the joint $XMM$-$Newton$ and $NuSTAR$ observations of the radio-quiet quasar QSO B2202$-$209. Using an optical observation from the Hale Telescope at the Palomar Observatory, we revise the redshift of the source from the previously reported $z=1.77$ to $z=0.532$, and we estimate the mass of the central black hole, $\\log (M_{\\rm BH}/M_{\\odot}) = 9.08 \\pm 0.18$. The X-ray spectrum of this source can be well described by a power-law of photon index $\\Gamma = 1.82 \\pm 0.05$ with $E_{\\rm cut} = 152_{-54}^{+103}\\,{\\rm keV}$, in the rest frame of the source. Assuming a Comptonisation model, we estimate the coronal temperature to be $kT_{\\rm e}=42\\pm 3 \\,{\\rm keV}$ and $kT_{\\rm e}= 56 \\pm 3\\,{\\rm keV}$ for a spherical and a slab geometry, respectively. The coronal properties are comparable to the ones derived for local AGN, despite a difference of around one order of magnitude in black hole mass and X-ray luminosity ($L_{2-10} = 1.93\\times 10^{45}\\,{\\rm erg\\,s^{-1}}$). The quasar is X-ray lo...

  7. Incidence of MgII absorbers towards Blazars and the GRB/QSO puzzle

    CERN Document Server

    Bergeron, Jacqueline; Ménard, Brice

    2010-01-01

    In order to investigate the origin of the excess of strong MgII systems towards GRB afterglows as compared to QSO sightlines, we have measured the incidence of MgII absorbers towards a third class of objects: the Blazars. This class includes the BL Lac object population for which a tentative excess of MgII systems had already been reported. We observed with FORS1 at the ESO-VLT 42 Blazars with an emission redshift 0.8 1.0 A) and weaker (0.3 < w_r(2796) < 1.0 A) MgII systems. The dependence on velocity separation with respect to the background Blazars indicates, at the ~1.5 sigma level, a potential excess for beta = v/c ~0.1. We show that biases involving dust extinction or gravitational amplification are not likely to notably affect the incidence of MgII systems towards Blazars. Finally we discuss the physical conditions required for these absorbers to be ga s entrained by the powerful Blazar jets. More realistic numerical modelling of jet-ambient gas interaction is required to reach any firm conclusion...

  8. Gas reservoir of a hyper-luminous QSO at z=2.6

    CERN Document Server

    Feruglio, C; Fiore, F; Krips, M; Brusa, M; Daddi, E; Gavignaud, I; Maiolino, R; Piconcelli, E; Sargent, M; Vignali, C; Zappacosta, L

    2014-01-01

    Understanding the relationship between the formation and evolution of galaxies and their central super massive black holes (SMBH) is one of the main topics in extragalactic astrophysics. Links and feedback may reciprocally affect both black hole and galaxy growth. Observations of the CO line at redshifts of 2-4 are crucial to investigate the gas mass, star formation activity and accretion onto SMBHs, as well as the effect of AGN feedback. Potential correlations between AGN and host galaxy properties can be highlighted by observing extreme objects. Despite their luminosity, hyper-luminous QSOs at z=2-4 are still little studied at mm wavelengths. We targeted CO(3-2) in ULAS J1539+0557, an hyper-luminos QSO (Lbol> 10^48 erg/s) at z=2.658, selected through its unusual red colors in the UKIDSS Large Area Survey (ULAS). We find a molecular gas mass of 4.1+-0.8 10^10 Msun, and a gas fraction of 0.4-0.1, depending mostly on the assumed source inclination. We also find a robust lower limit to the star-formation rate (...

  9. Detection of very high energy gamma-ray emission from the gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes

    CERN Document Server

    Ahnen, M L; Antonelli, L A; Antoranz, P; Arcaro, C; Babic, A; Banerjee, B; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Berti, A; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Buson, S; Carosi, A; Chatterjee, A; Clavero, R; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Lotto, B; Wilhelmi, E de Oña; Di Pierro, F; Doert, M; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Glawion, D Eisenacher; Elsaesser, D; Engelkemeier, M; Ramazani, V Fallah; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giammaria, P; Godinović, N; Gora, D; Guberman, D; Hadasch, D; Hahn, A; Hayashida, M; Herrera, J; Hose, J; Hrupec, D; Hughes, G; Idec, W; Kodani, K; Konno, Y; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; Majumdar, P; Makariev, M; Mallot, K; Maneva, G; Manganaro, M; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Moretti, E; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Nogués, L; Paiano, S; Palacio, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Pedaletti, G; Peresano, M; Perri, L; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Garcia, J R; Reichardt, I; Rhode, W; Ribó, M; Rico, J; Saito, T; Satalecka, K; Schroeder, S; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Strzys, M; Surić, T; Takalo, L; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Torres, D F; Toyama, T; Treves, A; Vanzo, G; Verguilov, V; Vovk, I; Ward, J E; Will, M; Wu, M H; Zanin, R; Desiante, R

    2016-01-01

    Context. QSO B0218+357 is a gravitationally lensed blazar located at a redshift of 0.944. The gravitational lensing splits the emitted radiation into two components, spatially indistinguishable by gamma-ray instruments, but separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes. Aims. The spectral energy distribution of QSO B0218+357 can give information on the energetics of z ~ 1 very high energy gamma- ray sources. Moreover the gamma-ray emission can also be used as a probe of the extragalactic background light at z ~ 1. Methods. MAGIC performed observations of QSO B0218+357 during the expected arrival time of the delayed component of the emission. The MAGIC and Fermi-LAT observations were accompanied by quasi-simultaneous optical data from the KVA telescope and X-ray observations by Swift-XRT. We construct a multiwavelength spectral energy distribution of QSO B0218+357 and use it to model the source. The GeV and...

  10. How Lyman Alpha Emission Depends On Galaxy Stellar Mass

    CERN Document Server

    Oyarzún, Grecco A; González, Valentino; Mateo, Mario; Bailey, John I; Finkelstein, Steven L; Lira, Paulina; Crane, Jeffrey D; Olszewski, Edward W

    2016-01-01

    In this work, we show how the stellar mass (M) of galaxies affects the 3Ly-alpha equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M range 7.6 < logM/Msun < 10.6 from the 3D-HST/CANDELS survey. We perform spectroscopic observations of this sample using the Michigan/Magellan Fiber System, allowing us to measure Ly-alpha fluxes and use 3D-HST/CANDELS ancillary data. In order to study the Ly-alpha EW distribution dependence on M, we split the whole sample in three stellar mass bins. We find that, in all bins, the distribution is best represented by an exponential profile of the form dN(M)/dEW= A(M)exp(-EW/W0(M))/W0(M). Through a Bayesian analysis, we confirm that lower M galaxies have higher Ly-alpha EWs. We also find that the fraction A of galaxies featuring emission and the e-folding scale W0 of the distribution anti- correlate with M, recovering expressions of the forms A(M)= -0.26(.13) logM/Msun+3.01(1.2) and W0(M)= -15.6(3.5) logM/Msun +166(34). Th...

  11. Modeling the Lyα Forest in Collisionless Simulations

    Science.gov (United States)

    Sorini, Daniele; Oñorbe, José; Lukić, Zarija; Hennawi, Joseph F.

    2016-08-01

    Cosmological hydrodynamic simulations can accurately predict the properties of the intergalactic medium (IGM), but only under the condition of retaining the high spatial resolution necessary to resolve density fluctuations in the IGM. This resolution constraint prohibits simulating large volumes, such as those probed by BOSS and future surveys, like DESI and 4MOST. To overcome this limitation, we present “Iteratively Matched Statistics” (IMS), a novel method to accurately model the Lyα forest with collisionless N-body simulations, where the relevant density fluctuations are unresolved. We use a small-box, high-resolution hydrodynamic simulation to obtain the probability distribution function (PDF) and the power spectrum of the real-space Lyα forest flux. These two statistics are iteratively mapped onto a pseudo-flux field of an N-body simulation, which we construct from the matter density. We demonstrate that our method can reproduce the PDF, line of sight and 3D power spectra of the Lyα forest with good accuracy (7%, 4%, and 7% respectively). We quantify the performance of the commonly used Gaussian smoothing technique and show that it has significantly lower accuracy (20%-80%), especially for N-body simulations with achievable mean inter-particle separations in large-volume simulations. In addition, we show that IMS produces reasonable and smooth spectra, making it a powerful tool for modeling the IGM in large cosmological volumes and for producing realistic “mock” skies for Lyα forest surveys.

  12. The brightest Ly α emitter: Pop III or black hole?

    NARCIS (Netherlands)

    Pallottini, A.; Ferrara, A.; Pacucci, F.; Gallerani, S.; Salvadori, S.; Schneider, R.; Schaerer, D.; Sobral, D.; Matthee, J.

    2015-01-01

    CR7 is the brightest z = 6.6 Ly α emitter (LAE) known to date, and spectroscopic follow-up by Sobral et al. suggests that CR7 might host Population (Pop) III stars. We examine this interpretation using cosmological hydrodynamical simulations. Several simulated galaxies show the same `Pop III wave' p

  13. The nature of z ~ 2.3 Lyman-alpha emitters

    CERN Document Server

    Nilsson, Kim K; Møller, Palle; Möller-Nilsson, Ole; Tapken, Christian; Freudling, Wolfram; Fynbo, Johan P U

    2010-01-01

    We study the multi-wavelength properties of a set of 171 Ly-alpha emitting candidates at redshift z = 2.25 found in the COSMOS field. The candidates are shown to have different properties from those of Ly-alpha emitters found at higher redshift, by fitting the spectral energy distributions (SEDs) using a Monte-Carlo Markov-Chain technique and including nebular emission in the spectra. The dust contents and stellar masses are both higher, with A_V = 0.0 - 2.0 mag and stellar masses in the range log M_* = 9.0 - 11.0 M_sun. Young population ages are well constrained, but older population ages are typically unconstrained. In 40 % of the galaxies only a single, young population of stars is observed. We show that the ages and Ly-alpha fluxes of the best fit galaxies are correlated with their dust properties, with higher dust extinction in younger galaxies. We conclude that the stellar properties of Ly-alpha emitters at z = 2.25 are different from those at higher redshift and that they are very diverse. Ly-alpha sel...

  14. Lyman {\\alpha} radiative transfer in the high-redshift, dusty Universe

    CERN Document Server

    Laursen, Peter

    2010-01-01

    The significance of the Ly{\\alpha} emission line as a probe of the high-redshift Universe has long been established. Originating mainly in the vicinity of young, massive stars and in association with accretion of large bulks of matter, it is ideal for detecting young galaxies, the fundamental building blocks of our Universe. Since many different processes shape the spectrum and the spatial distribution of the Ly{\\alpha} photons in various ways, a multitude of physical properties of galaxies can be unveiled. However, this also makes the interpretation of Ly{\\alpha} observations notoriously difficult. Because Ly{\\alpha} is a resonant line, it scatters on neutral hydrogen, having its path length from the source to our telescopes vastly increased, and taking it through regions of unknown physical conditions. In this work, a numerical code capable of calculating realistically the radiative transfer of Ly{\\alpha} is presented. The code is capable of performing the radiative transfer in an arbitrary and adaptively r...

  15. Evidence for a direct collapse black hole in the Lyman-alpha source CR7

    CERN Document Server

    Smith, Aaron; Loeb, Abraham

    2016-01-01

    Throughout the epoch of reionization the most luminous Ly{\\alpha} emitters are capable of ionizing their own local bubbles. The CR7 galaxy at $z \\approx 6.6$ stands out for its combination of exceptionally bright Ly{\\alpha} and HeII 1640 Angstrom line emission but absence of metal lines. As a result CR7 may be the first viable candidate host of a young primordial starburst or direct collapse black hole. High-resolution spectroscopy reveals a +160 km s$^{-1}$ velocity offset between the Ly{\\alpha} and HeII line peaks while the spatial extent of the Ly{\\alpha} emitting region is $\\sim 16$ kpc. The observables are indicative of an outflow signature produced by a strong central source. We present one-dimensional radiation-hydrodynamics simulations incorporating accurate Ly{\\alpha} feedback and ionizing radiation to investigate the nature of the CR7 source. We find that a Population III star cluster with $10^5$ K blackbody emission ionizes its environment too efficiently to generate a significant velocity offset. ...

  16. VLT adaptive optics imaging of QSO host galaxies and close environment at z ~2.5: results from a pilot program

    CERN Document Server

    Falomo, R; Scarpa, R; Treves, A

    2004-01-01

    We report ESO-VLT near-infrared adaptive optics imaging of one radio-loud (PKS 0113-283) and two radio-quiet (Q 0045-3337 and Q 0101-337) QSOs at z > 2. In the first case, we are able to resolve the QSO and find that it is hosted by an elliptical of absolute magnitude M(K) = -27.6. For the other two objects, no extended emission has been unambiguously detected. This result, though restricted to a single object, extends up to z ~2.5 the finding that cosmic evolution of radio-loud QSO hosts follows the trend expected for luminous and massive spheroids undergoing passive evolution. For Q 0045-3337, our high resolution images show that it is located 1.2 arcsec from a K = 17.5 foreground disc galaxy, which may act as a gravitational lens, since the QSO most probably lies within the galaxy Einstein radius.

  17. A low-redshift low luminosity QSO sample: Comparison with NUGA galaxies and PG QSOs and first interferometric images of three sample members

    CERN Document Server

    Moser, Lydia; Fischer, Sebastian; Busch, Gerold; Valencia-S., Monica; Eckart, Andreas; Krips, Melanie; Scharwaechter, Julia

    2013-01-01

    The low luminosity QSO (LLQSO) sample consists of type 1 active galactic nuclei (AGN) up to a redshift of z=0.06 in the Hamburg/ESO QSO survey. Its purpose is to study how the brightest AGN in the nearby universe evolve with respect to AGN activity and host properties as a function of redshift. We show that our sample lies well between the NUclei of GAlaxies (NUGA) sample and the Palomar Green (PG) QSO sample in terms of redshift, gas masses and luminosities and seems to connect them. The continuous growth in mass, luminosity and, linked to this, the AGN activity over the samples has either a statistical reason or is indicative of an evolutionary link between the different populations and might be related to cosmic downsizing. In addition, we present first results of our observations of three galaxies from our sample with the Submillimeter Array (SMA).

  18. Coronal properties of the luminous radio-quiet quasar QSO B2202-209

    Science.gov (United States)

    Kammoun, E. S.; Risaliti, G.; Stern, D.; Jun, H. D.; Graham, M.; Celotti, A.; Behar, E.; Elvis, M.; Harrison, F. A.; Matt, G.; Walton, D. J.

    2017-02-01

    We present an analysis of the joint XMM-Newton and NuSTAR observations of the radio-quiet quasar QSO B2202-209. Using an optical observation from the Hale Telescope at the Palomar Observatory, we revise the redshift of the source from the previously reported z = 1.77 to z = 0.532, and we estimate the mass of the central black hole, log (MBH/M⊙) = 9.08 ± 0.18. The X-ray spectrum of this source can be well described by a power law of photon index Γ = 1.82 ± 0.05 with E_cut = 152_{-54}^{+103} keV, in the rest frame of the source. Assuming a Comptonization model, we estimate the coronal temperature to be kTe = 42 ± 3 keV and kTe = 56 ± 3 keV for a spherical and a slab geometry, respectively. The coronal properties are comparable to the ones derived for local active galactic nuclei, despite a difference of around one order of magnitude in black hole mass and X-ray luminosity (L2 - 10 = 1.93 × 1045 erg s-1). The quasar is X-ray loud, with an unusually flat observed optical-to-X-ray spectral slope αOX = 1.00 ± 0.02, and has an exceptionally strong optical [O III] line. Assuming that both the X-ray emission and the [O III] line are isotropic, these two extreme properties can be explained by a nearly edge-on disc, leading to a reduction in the observed ultraviolet continuum light.

  19. A Monster At Any Other Epoch: Are Intermediate Redshift ULIRGs the Progenitors of QSO Host Galaxies?

    Science.gov (United States)

    Rothberg, Barry; Fischer, Jackie; Rodrigues, Myriam; Pirzkal, Nor

    2015-08-01

    There is a clear progression from merger-induced SF to QSO activity via Ultraluminous Infrared Galaxies (ULIRGs). While not all mergers are ULIRGs, multi-wavelength imaging confirms that all local ULIRGs are mergers. At 0.4 1 are responsible for ˜ 70% of the co-moving IR density. At these earlier epochs ULIRGs contained more gas, formed stars faster, and their number density was much higher. At z>1 there are conflicting conclusions about ULIRGs. Many studies conclude they are massive star-forming galaxies, not major mergers nor AGN. Nearly all studies of ULIRGs at z > 0.4 have selected these systems via scaling observed 24μm or 170μm Spitzer fluxes to integrated 8-1000μm fluxes and inferring masses from scaling photometric fluxes or millimeter observations of CO gas emission. These methods often rely heavily on uncertain assumptions (e.g. gas conversions, SED fitting and templates). Instead, we have assembled a representative sample of "classically" selected ULIRGs (60 and 100μm IRAS fluxes and 12 and 25μm WISE fluxes) for 0.4 < z < 1.0 and obtained optical and near-IR imaging and spectroscopy from Hubble Space Telescope, Keck, and the Large Binocular Telescope. We use the same techniques for measuring the dynamical and BH masses of ULIRGs in the local Universe to measure these parameters in more distant systems. Unlike other methods, we directly measure the mass at an epoch when galaxy formation and evolution appears to have changed dramatically from what we see today and compare these intermediate redshift ULIRGs with their counterparts in the local Universe. Our restframe optical and UV spectroscopy also allow us to directly probe gas-metallicities, outflows, and measure the properties of their stellar populations. Our results indicate that these intermediate redshift ULIRGs are dynamically similar to their local counterparts.

  20. File list: Oth.Brs.10.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Brs.10.AllAg.LY2 hg19 TFs and others Breast LY2 SRX425995,SRX095408,SRX095407,S...RX425996 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Brs.10.AllAg.LY2.bed ...

  1. File list: NoD.Brs.20.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  2. File list: ALL.Brs.50.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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    Lifescience Database Archive (English)

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  5. File list: NoD.Brs.05.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  6. File list: His.Bld.50.AllAg.OCI-LY1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  7. File list: Pol.Bld.20.AllAg.OCI-LY1 [Chip-atlas[Archive

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  8. File list: Pol.Bld.10.AllAg.OCI-LY1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  9. File list: Oth.Brs.05.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. File list: NoD.Brs.10.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  12. File list: NoD.Brs.50.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  13. File list: Oth.Brs.50.AllAg.LY2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  14. File list: Pol.Bld.50.AllAg.OCI-LY1 [Chip-atlas[Archive

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  15. File list: Pol.Bld.05.AllAg.OCI-LY1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  16. Providing Stringent Star Formation Rate Limits of z ˜ 2 QSO Host Galaxies at High Angular Resolution

    Science.gov (United States)

    Vayner, Andrey; Wright, Shelley A.; Do, Tuan; Larkin, James E.; Armus, Lee; Gallagher, S. C.

    2016-04-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ˜ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ˜0.″2 (˜1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (zHα = 2.182) and SDSS J0925+0655 (zHα = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M⊙ yr-1 originating from a compact region that is kinematically offset by 290-350 km s-1. For SDSS J0925+0655 we infer a SFR of 29 M⊙ yr-1 distributed over three clumps that are spatially offset by ˜7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M⊙ yr-1 kpc-2. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M⊙ yr-1 kpc-2. These IFS observations indicate that while the central black hole is accreting mass at 10%-40% of the Eddington rate, if star formation is present in the host (1.4-20 kpc) it would have to occur diffusely with significant

  17. Time-variability of the fine-structure constant expected from the Oklo constraint and the QSO absorption lines

    CERN Document Server

    Fujii, Y

    2003-01-01

    The data from the QSO absorption lines indicating a nonzero time-variability of the fine-structure constant has been re-analyzed on the basis of a "damped-oscillator" fit, as motivated by the same type of behavior of a scalar field, dilaton, which mimics a cosmological constant to understand the accelerating universe. We find nearly as good fit to the latest data as the simple weighted mean. In this way, we offer a way to fit the more stringent result from the Oklo phenomenon, as well.

  18. Time-variability of the fine-structure constant expected from the Oklo constraint and the QSO absorption lines

    Science.gov (United States)

    Fujii, Yasunori

    2003-10-01

    The data from the QSO absorption lines indicating a nonzero time-variability of the fine-structure constant has been re-analyzed on the basis of a ``damped-oscillator'' fit, as motivated by the same type of behavior of a scalar field, dilaton, which mimics a cosmological constant to understand the accelerating universe. We find nearly as good fit to the latest data as the simple weighted mean. In this way, we offer a way to fit the more stringent result from the Oklo phenomenon, as well.

  19. Geocoronal Lyman Alpha Observations with COS

    Science.gov (United States)

    Ake, Thomas B.

    2012-01-01

    The time-tagged mode of the Cosmic Origins Spectrograph (COS) provides a convenient method of studying the orbital variation of geocoronal Lyman-alpha emission at the altitude of HST. We have analyzed G130M blank sky exposures from scheduled STIS parallels and observations for which the target acquisition failed. We supplement these with observations of WD standard stars from flat field and sensitivity monitoring programs where the stellar Lyα profile can be modeled and its contribution to the geocoronal emission removed. Data were corrected for time-dependent sensitivity changes and gain sag. The measurements have been fit by an analytical model based on the orbital position of HST and the angle between the target and the Earth as seen from HST. The Lyα emission varies from less than 2 kR for a target observed at orbit midnight to 37 kR for one observed at the bright Earth limb at orbit noon. A long-term trend of increasing flux is evident, consistent with solar Lyα measurements by SOLSTICE on SORCE as the next solar maximum is approached. We expect the irradiance at solar maximum to be at least 50-55 kR. This level still should not trigger local count rate violations for the FUV detector, but will accelerate gain sag of the microchannel plates in the regions where Lyα falls.

  20. Pharmacological characterization of LY233053: A structurally novel tetrazole-substituted competitive N-methyl-D-aspartic acid antagonist with a short duration of action

    Energy Technology Data Exchange (ETDEWEB)

    Schoepp, D.D.; Ornstein, P.L.; Leander, J.D.; Lodge, D.; Salhoff, C.R.; Zeman, S.; Zimmerman, D.M. (Eli Lilly and Company, Indianapolis, IN (USA))

    1990-12-01

    This study reports the activity of a structurally novel excitatory amino acid receptor antagonist, LY233053 (cis-(+-)-4-((2H-tetrazol-5-yl)methyl)piperidine-2-carboxylic acid), the first tetrazole-containing competitive N-methyl-D-aspartic acid (NMDA) antagonist. LY233053 potently inhibited NMDA receptor binding to rat brain membranes as shown by the in vitro displacement of (3H) CGS19755 (IC50 = 107 +/- 7 nM). No appreciable affinity in (3H)alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) or (3H)kainate binding assays was observed (IC50 values greater than 10,000 nM). In vitro NMDA receptor antagonist activity was further demonstrated by selective inhibition of NMDA-induced depolarization in cortical wedges (IC50 = 4.2 +/- 0.4 microM vs. 40 microM NMDA). LY233053 was effective after in vivo systemic administration in a number of animal models. In neonatal rats, LY233053 selectively blocked NMDA-induced convulsions (ED50 = 14.5 mg/kg i.p.) with a relatively short duration of action (2-4 hr). In pigeons, LY233053 potently antagonized (ED50 = 1.3 mg/kg i.m.) the behavioral suppressant effects of 10 mg/kg of NMDA. However, a dose of 160 mg/kg, i.m., was required to produce phencyclidine-like catalepsy in pigeons. In mice, LY233053 protected against maximal electroshock-induced seizures at lower doses (ED50 = 19.9 mg/kg i.p.) than those that impaired horizontal screen performance (ED50 = 40.9 mg/kg i.p.). Cholinergic and GABAergic neuronal degenerations after striatal infusion of NMDA were prevented by single or multiple i.p. doses of LY233053. In summary, the antagonist activity of LY233053 after systemic administration demonstrates potential therapeutic value in conditions of neuronal cell loss due to NMDA receptor excitotoxicity.

  1. Ly6C- Monocytes Regulate Parasite-Induced Liver Inflammation by Inducing the Differentiation of Pathogenic Ly6C+ Monocytes into Macrophages.

    Directory of Open Access Journals (Sweden)

    Yannick Morias

    2015-05-01

    Full Text Available Monocytes consist of two well-defined subsets, the Ly6C+ and Ly6C- monocytes. Both CD11b+ myeloid cells populations have been proposed to infiltrate tissues during inflammation. While infiltration of Ly6C+ monocytes is an established pathogenic factor during hepatic inflammation, the role of Ly6C- monocytes remains elusive. Mice suffering experimental African trypanosome infection die from systemic inflammatory response syndrome (SIRS that is initiated by phagocytosis of parasites by liver myeloid cells and culminates in apoptosis/necrosis of liver myeloid and parenchymal cells that reduces host survival. C57BL/6 mice are considered as trypanotolerant to Trypanosoma congolense infection. We have reported that in these animals, IL-10, produced among others by myeloid cells, limits the liver damage caused by pathogenic TNF-producing Ly6C+ monocytes, ensuring prolonged survival. Here, the heterogeneity and dynamics of liver myeloid cells in T. congolense-infected C57/BL6 mice was further dissected. Moreover, the contribution of Ly6C- monocytes to trypanotolerance was investigated. By using FACS analysis and adoptive transfer experiments, we found that the accumulation of Ly6C- monocytes and macrophages in the liver of infected mice coincided with a drop in the pool of Ly6C+ monocytes. Pathogenic TNF mainly originated from Ly6C+ monocytes while Ly6C- monocytes and macrophages were major and equipotent sources of IL-10 within myeloid cells. Moreover, Nr4a1 (Nur77 transcription factor-dependent Ly6C- monocytes exhibited IL-10-dependent and cell contact-dependent regulatory properties contributing to trypanotolerance by suppressing the production of TNF by Ly6C+ monocytes and by promoting the differentiation of the latter cells into macrophages. Thus, Ly6C- monocytes can dampen liver damage caused by an extensive Ly6C+ monocyte-associated inflammatory immune response in T. congolense trypanotolerant animals. In a more general context, Ly6C- or Ly6C

  2. Corrosion of LY12 aluminum alloy in sodium chloride solution

    Institute of Scientific and Technical Information of China (English)

    程英亮; 张昭; 曹发和; 李劲风; 张鉴清; 王建明; 曹楚南

    2003-01-01

    The corrosion behavior of LY12 alloy in sodium chloride solution and its electrochemical noise were reported. The development of the micro-pits on the alloy surface was monitored by scanning electron microscopy, scanning tunneling microscopy, and electrochemical noise method. All the measurements show that the corrosion of LY12 alloy can be divided into two stages: a very reactive initial stage and a relative constant stable stage. The initial stage is corresponded to the adsorption of Cl ions and its reaction with the oxide film and the dissolution of Mg containing particles. The stable stage is corresponded to the development of the micro-pits by the galvanic attack formed by Al-Fe-Cu-Mn containing particles and the matrix. The initial stage lasts about 2-3 h while the stable stage dominates the whole corrosion process.

  3. A specific acid [alpha]-glucosidase in lamellar bodies of the human lung

    OpenAIRE

    Vries, A.C.J. de; Schram, A.W.; Tager, J.M.; Batenburg, J.J.

    2006-01-01

    In the present investigation, we have demonstrated that three lysosomal-type hydrolases, alpha-glucosidase, alpha-mannosidase and a phosphatase, are present in lamellar bodies isolated from adult human lung. The hydrolase activities that were studied, all showed an acidic pH optimum, which is characteristic for lysosomal enzymes. The properties of acid alpha-glucosidase in the lamellar body fraction and that in the lysosome-enriched fraction were compared. Using specific antibodies against ly...

  4. Spectroscopy of 7 Radio-Loud QSOs at 2alpha Nebulae Accreting onto Host Galaxies

    CERN Document Server

    Roche, Nathan; Binette, Luc

    2014-01-01

    We performed long-slit optical spectroscopy (GTC-OSIRIS) of 6 radio-loud QSOs at redshifts $2alpha$ emitting nebulae, and detect extended Lyman-$\\alpha$ emission for 4, with surface brightness $\\sim10^{-16}$ ergs $\\rm cm^{-2}s^{-1}arcsec^{-2}$ and line width FWHM 400-1100 (mean 863) km $\\rm s^{-1}$. We also observed the $z\\simeq 5.9$ radio-loud QSO, SDSS J2228+0110, and find evidence of a $\\geq 10$ kpc extended Lyman-$\\alpha$ emission nebula, a new discovery for this high-redshift object. Spatially-resolved kinematics of the 5 nebulae are examined by fitting the Lyman-$\\alpha$ wavelength at a series of positions along the slit. We found the line-of-sight velocity $\\Delta(v)$ profiles to be relatively flat. However, 3 of the nebulae appear systematically redshifted by 250-460 km $\\rm s^{-1}$ relative to the Lyman-$\\alpha$ line of the QSO (with no offset for the other two), which we argue is evidence for infall. One of these (Q0805+046) had a small ($...

  5. Constraining the Variation in Fine-Structure Constant Using SDSS DR8 QSO Spectra

    CERN Document Server

    Rahmani, H; Srianand, R

    2013-01-01

    We report a robust constrain on the possible variation of fine-structure constant, alpha = e^2/(hbar*c), obtained using O III 4959,5007, nebular emission lines from QSOs. We find Delta-alpha/alpha=-(2.1 +/- 1.6) x 10^(-5) based on a well selected sample of 2347 QSOs from Sloan Digital Sky Survey Data Release 8 with 0.02 < z < 0.74. Our result is consistent with a non-varying alpha at a level of 2 x 10^(-5) over approximately 7 Gyr. This is the largest sample of extragalactic objects yet used to constrain the variation of alpha. While this constraint is not as stringent as those determined using many-multiplet method it is free from various systematic effects. A factor of ~ 4 improvement in Delta-alpha/alpha achieved here compared to the previous study (Bahcall et al. 2004) is just consistent with what is expected based on a factor of 14 times bigger sample used here. This suggests that errors are mainly dominated by the statistical uncertainty. We also find the ratio of transition probabilities correspo...

  6. A New Population of High Redshift, Dusty Lyman-Alpha Emitters and Blobs Discovered by WISE

    CERN Document Server

    Bridge, Carrie R; Borys, Colin J K; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger L; Jarrett, Tom; Stanford, S Adam; Stern, Daniel; Tsai, Chao-Wei; Wright, Edward L; Wu, Jingwen

    2012-01-01

    We report a new technique to select 1.610^{13-14}L_sun) and warm colors, typically larger than submillimeter-selected galaxies (SMGs) and dust-obscured galaxies (DOGs). These traits are commonly associated with the dust being energized by intense AGN activity. We hypothesize that the combination of spatially extended Lyman-alpha, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing strong `feedback' transforming them from an extreme dusty starburst to a QSO.

  7. 5-Hydroxytryptamine(1F) receptors do not participate in vasoconstriction: lack of vasoconstriction to LY344864, a selective serotonin(1F) receptor agonist in rabbit saphenous vein.

    Science.gov (United States)

    Cohen, M L; Schenck, K

    1999-09-01

    Recently, several novel approaches to the treatment of migraine have been advanced, including selective 5-hydroxytryptamine (or serotonin) 1B/1D (5-HT(1B/1D)) receptor agonists such as sumatriptan and 5-HT(1F) receptor agonists such as LY344864. Many 5-HT(1B/1D) receptor agonists have been identified based on their ability to produce cerebral vascular contraction, whereas LY344864 was identified as an inhibitor of trigeminal nerve-mediated dural extravasation. In our study, several triptan derivatives were compared with LY344864 for their ability to contract the rabbit saphenous vein, a tissue used in the preclinical identification of sumatriptan-related agonists. Sumatriptan, zolmitriptan, rizatriptan, and naratriptan all contracted the rabbit saphenous vein from baseline tone, whereas LY344864 in concentrations up to 10(-4) M did not contract the rabbit saphenous vein. Furthermore, vascular contractions to sumatriptan were markedly augmented in the presence of prostaglandin F(2alpha) (PGF(2alpha)). However, even in the presence of PGF(2alpha) (3 x 10(-7) M), LY344864 did not contract the rabbit saphenous vein in concentrations well in excess of its 5-HT(1F) receptor affinity (pK(i) = 8.2). Only when concentrations exceeded those likely to activate 5-HT(1B) and 5-HT(1D) receptors (>10(-5) M) did modest contractile responses occur in the presence of PGF(2alpha). Use of these serotonergic agonists revealed a significant correlation between the contractile potency in the rabbit saphenous vein and the affinities of these agonists at 5-HT(1B) and 5-HT(1D) receptors, although contractile agonist potencies were not quantitatively similar to 5-HT(1B) or 5-HT(1D) receptor affinities. In contrast, no significant correlation existed between the contractile potencies of these serotonergic agonists in the rabbit saphenous vein and their affinity at 5-HT(1F) receptors. These data support the contention that activation of 5-HT(1F) receptors will not result in vascular

  8. Expression of the Ly-6 family proteins Lynx1 and Ly6H in the rat brain is compartmentalized, cell-type specific, and developmentally regulated

    DEFF Research Database (Denmark)

    Thomsen, Morten Skøtt; Cinar, Betül; Jensen, Majbrit Myrup

    2014-01-01

    The Ly-6 superfamily of proteins, which affects diverse processes in the immune system, has attracted renewed attention due to the ability of some Ly-6 proteins to bind to and modulate the function of neuronal nicotinic acetylcholine receptors (nAChRs). However, there is a scarcity of knowledge...

  9. Baryon Acoustic Oscillations in the Ly-\\alpha\\ forest of BOSS quasars

    CERN Document Server

    Busca, Nicolás G; Rich, James; Bailey, Stephen; Font-Ribera, Andreu; Kirkby, David; Goff, J -M Le; Pieri, Matthew M; Slosar, Anze; Aubourg, Éric; Bautista, Julian E; Bizyaev, Dmitry; Blomqvist, Michael; Bolton, Adam S; Bovy, Jo; Brewington, Howard; Borde, Arnaud; Brinkmann, J; Carithers, Bill; Croft, Rupert A C; Dawson, Kyle S; Ebelke, Garrett; Eisenstein, Daniel J; Hamilton, Jean-Christophe; Ho, Shirley; Hogg, David W; Honscheid, Klaus; Lee, Khee-Gan; Lundgren, Britt; Malanushenko, Elena; Malanushenko, Viktor; Margala, Daniel; Maraston, Claudia; Mehta, Kushal; Miralda-Escudé, Jordi; Myers, Adam D; Nichol, Robert C; Noterdaeme, Pasquier; Olmstead, Matthew D; Oravetz, Daniel; Palanque-Delabrouille, Nathalie; Pan, Kaike; Pâris, Isabelle; Percival, Will J; Petitjean, Patrick; Roe, N A; Rollinde, Emmanuel; Ross, Nicholas P; Rossi, Graziano; Schlegel, David J; Schneider, Donald P; Shelden, Alaina; Sheldon, Erin S; Simmons, Audrey; Snedden, Stephanie; Tinker, Jeremy L; Viel, Matteo; Weaver, Benjamin A; Weinberg, David H; White, Martin; Yèche, Christophe; York, Donald G; Zhao, Gong-Bo

    2012-01-01

    We report a detection of the baryon acoustic oscillation (BAO) feature in the three-dimensional correlation function of the transmitted flux fraction in the \\Lya forest of high-redshift quasars. The study uses 48,640 quasars in the redshift range $2.1\\le z \\le 3.5$ from the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). At a mean redshift $z=2.3$, we measure the monopole and quadrupole components of the correlation function for separations in the range $20\\hMpc

  10. Rayleigh Scattering Cross Section Redward of Ly$\\alpha$ by Atomic Hydrogen

    OpenAIRE

    Lee, Hee-Won; Kim, Hee Il

    2004-01-01

    We present a low energy expansion of the Kramers-Heisenberg formula for atomic hydrogen in terms of $(\\omega/\\omega_l)$, where $\\omega_l$ and $\\omega$ are the angular frequencies corresponding to the Lyman limit and the incident radiation, respectively. The leading term is proportional to $(\\omega/\\omega_l)^4$, which admits a well-known classical interpretation. With higher order terms we achieve accuracy with errors less than 4 % of the scattering cross sections in the region $\\omega/\\omega_...

  11. Dissecting the Gaseous Halos of z~2 Damped Ly$\\alpha$ Systems with Close Quasar Pairs

    CERN Document Server

    Rubin, Kate H R; Prochaska, J Xavier; Simcoe, Robert A; Myers, Adam; Lau, Marie Wingyee

    2014-01-01

    We use spectroscopy of close pairs of quasars to study diffuse gas in the circumgalactic medium (CGM) surrounding a sample of 40 Damped Lya systems (DLAs). The primary sightline in each quasar pair probes an intervening DLA in the redshift range 1.6 10^17.2 cm^-2) to be greater than ~30% within $R_{\\perp} 0.2 Ang occurs with an incidence f_C (W_1526 > 0.2 Ang) = 20(+12/-8)% within $R_{\\perp} 0.2 Ang) = 57(+12/-13)% within $R_{\\perp} 98% confidence, suggesting that DLAs arise close to the centers of their host halos rather than on their outskirts. Finally, the average Lya, CII and CIV equivalent widths are consistent with those measured around z~2 Lyman Break Galaxies. Assuming that DLAs trace a galaxy population with lower masses and luminosities, this finding implies that the absorption strength of cool circumgalactic material has a weak dependence on dark matter halo mass for M_h < 10^12 M_sun.

  12. Deep Ly alpha imaging of two z=2.04 GRB host galaxy fields

    DEFF Research Database (Denmark)

    Fynbo, J.P.U.; Møller, Per; Thomsen, Bente

    2002-01-01

    We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest-frame equ......We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest...

  13. Deep Ly alpha imaging of two z=2.04 GRB host galaxy fields

    DEFF Research Database (Denmark)

    Fynbo, J.P.U.; Møller, Per; Thomsen, Bente

    2002-01-01

    We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest-frame equ......We report on the results of deep narrow-band Lyalpha and broad-band U and I imaging of the fields of two Gamma-Ray bursts at redshift z = 2.04 (GRB 000301C and GRB 000926). We find that the host galaxy of GRB 000926 is an extended (more than 2 arcsec), strong Lyalpha emitter with a rest...

  14. Detection of warm and cold phases of the neutral ISM in a damped Ly alpha absorber

    NARCIS (Netherlands)

    Lane, WM; Briggs, FH; Smette, A

    2000-01-01

    present a detailed study of the HI 21 cm absorption system at z = 0.0912 toward the radio quasar B0738+313. The uncommonly narrow main absorption line and weak secondary line are resolved for the first time and have FWHM velocities of Delta v(1) = 3.7 and Delta v(2) = 2.2 km s(-1) (main and secondar

  15. The CALYMHA survey: Lyα luminosity function and global escape fraction of Lyα photons at z = 2.23

    Science.gov (United States)

    Sobral, David; Matthee, Jorryt; Best, Philip; Stroe, Andra; Röttgering, Huub; Oteo, Iván; Smail, Ian; Morabito, Leah; Paulino-Afonso, Ana

    2017-04-01

    We present the CAlibrating LYMan-α with Hα (CALYMHA) pilot survey and new results on Lyman α (Lyα) selected galaxies at z ∼ 2. We use a custom-built Lyα narrow-band filter at the Isaac Newton Telescope, designed to provide a matched volume coverage to the z = 2.23 Hα HiZELS survey. Here, we present the first results for the COSMOS and UDS fields. Our survey currently reaches a 3σ line flux limit of ∼4 × 10-17 erg s-1 cm-2, and a Lyα luminosity limit of ∼1042.3 erg s-1. We find 188 Lyα emitters over 7.3 × 105 Mpc3, but also find significant numbers of other line-emitting sources corresponding to He II, C III] and C IV emission lines. These sources are important contaminants, and we carefully remove them, unlike most previous studies. We find that the Lyα luminosity function at z = 2.23 is very well described by a Schechter function up to LLy α ≈ 1043 erg s-1 with L^{ast }=10^{42.59^{+0.16}_{-0.08}} erg s-1, φ ^{ast }=10^{-3.09^{+0.14}_{-0.34}} Mpc-3 and α = -1.75 ± 0.25. Above LLy α ≈ 1043 erg s-1, the Lyα luminosity function becomes power-law like, driven by X-ray AGN. We find that Lyα-selected emitters have a high escape fraction of 37 ± 7 per cent, anticorrelated with Lyα luminosity and correlated with Lyα equivalent width. Lyα emitters have ubiquitous large (≈40 kpc) Lyα haloes, ∼2 times larger than their Hα extents. By directly comparing our Lyα and Hα luminosity functions, we find that the global/overall escape fraction of Lyα photons (within a 13 kpc radius) from the full population of star-forming galaxies is 5.1 ± 0.2 per cent at the peak of the star formation history. An extra 3.3 ± 0.3 per cent of Lyα photons likely still escape, but at larger radii.

  16. The evolution of superbubbles and the detection of Lyman $\\alpha$ in star-forming galaxies

    CERN Document Server

    Tenorio-Tagle, G; Kunth, D; Terlevich, E; Terlevich, R J; Tenorio-Tagle, Guillermo; Silich, Sergey A.; Kunth, Daniel; Terlevich, Elena; Terlevich, Roberto

    1999-01-01

    The detection of Ly alpha emission in star-forming galaxies in different shapes and intensities (always smaller than predicted for case B recombination) has puzzled the astronomical community for more than a decade. Here we use two dimensional calculations to follow the evolution of superbubbles and of the H II regions generated by the output of UV photons from massive stars. We show the impact caused by massive star formation in the ISM of different galaxies and we look at the conditions required to detect Ly alpha emission from a nuclear H II region, and the variety of profiles that may be expected as a function of time.

  17. Characterization and mapping to human chromosome 8q24.3 of Ly-6-related gene 9804 encoding an apparent homologue of mouse TSA-1.

    Science.gov (United States)

    Shan, X; Bourdeau, A; Rhoton, A; Wells, D E; Cohen, E H; Landgraf, B E; Palfree, R G

    1998-01-01

    The 9804 gene, which encodes a human Ly-6 protein most similar to mouse differentiation Ag TSA-1/Sca-2, has also been called RIG-E. Like mouse TSA-1, it has a broad tissue distribution with varied expression levels in normal human tissues and tumor cell lines. Like some members of the murine Ly-6 family, the 9804 gene is responsive to IFNs, particularly IFN-alpha. Overlapping genomic fragments spanning the 9804 gene (5543 bp) have been isolated and characterized. The gene organization is analogous to that of known mouse Ly-6 genes. The first exon, 2296 bp upstream from exon II, is entirely untranslated. The three coding exons (II, III, and IV) are separated by short introns of 321 and 131 bp, respectively. Primers were developed for specific amplification of 9804 gene fragments. Screening of human-hamster somatic cell hybrids and yeast artificial chromosomes (YACs) indicated that the gene is distal to c-Myc, located in the q arm of human chromosome 8. No positives were detected from the Centre d'Etude du Polymorphisme Humain mega-YAC A or B panels, nor from bacterial artificial chromosome libraries; two positive cosmids (c101F1 and c157F6) were isolated from a human chromosome 8 cosmid library (LA08NC01). Fluorescence in situ hybridization of metaphase spreads of chromosome 8, containing hybrid cell line 706-B6 clone 17 (CL-17) with cosmid c101F1, placed the 9804 gene close to the telomere at 8q24.3. This mapping is significant, since the region shares a homology with a portion of mouse chromosome 15, which extends into band E where Ly-6 genes reside. Moreover, the gene encoding E48, the homologue of mouse Ly-6 molecule ThB, has also been mapped to 8q24.

  18. Lyα Emitter Galaxies at z˜ 2.8 in the Extended Chandra Deep Field South. I. Tracing the Large-scale Structure via Lyα Imaging

    Science.gov (United States)

    Zheng, Zhen-Ya; Malhotra, Sangeeta; Rhoads, James E.; Finkelstein, Steven L.; Wang, Jun-Xian; Jiang, Chun-Yan; Cai, Zheng

    2016-10-01

    We present a narrowband survey with three adjacent filters for z = 2.8-2.9 Lyman alpha (Lyα) emitter (LAE) galaxies in the Extended Chandra Deep Field South (ECDFS), along with spectroscopic follow-up. With a complete sample of 96 LAE candidates in the narrowband NB466, we confirm the large-scale structure at z ˜ 2.8 suggested by previous spectroscopic surveys. Compared to the blank field detected with the other two narrowband filters NB470 and NB475, the LAE-density excess in NB466 (900 arcmin2) is ˜ 6.0 ± 0.8 times the standard deviation expected at z ˜ 2.8, assuming a linear bias of 2. The overdense large-scale structure in NB466 can be decomposed into four protoclusters, whose overdensities (each within an equivalent comoving volume 153 Mpc3) relative to the blank field (NB470+NB475) are in the range of 4.6-6.6. These four protoclusters are expected to evolve into a Coma-like cluster (M ≥ 1015 M ⊙) at z ˜ 0. We also investigate the various properties of LAEs at z = 2.8-2.9 and their dependence on the environment. The average star formation rates derived from the Lyα, rest-frame UV, and X-ray bands are ˜4, 10, and <16 M ⊙ yr-1, respectively, implying a Lyα escape fraction of 25% ≲ {f}{{ESC}}{Lyα } ≲ 40% and a UV continuum escape fraction of {f}{{ESC}}{{UV,cont}} ≳ 62% for LAEs at z ˜ 2.8. The Lyα photon density calculated from the integrated Lyα luminosity function in the overdense field (NB466) is ˜50% higher than that in the blank field (NB470+NB475), and more bright LAEs are found in the overdense field. The three brightest LAEs, including a quasar at z = 2.81, are all detected in the X-ray band and in NB466. These three LAE-active galactic nuclei contribute an extra 20%-30% Lyα photon density compared to other LAE galaxies. Furthermore, we find that LAEs in overdense regions have larger equivalent width values, bluer U - B and V - R (˜2-3σ) colors compared with those in lower density regions, indicating that LAEs in overdense

  19. Protective Role of Rho Guanosine Diphosphate Dissociation Inhibitor, Ly-GDI, in Pulmonary Alveolitis.

    Science.gov (United States)

    Yan, Chunguang; Wang, Ximo; Liu, Yanlan; Abdulnour, Raja-Elie; Wu, Min; Gao, Hongwei

    2015-01-01

    Growing evidences indicate that Ly-GDI, an inhibitory protein of Rho GTPases, plays an essential role in regulating actin cytoskeletal alteration which is indispensible for the process such as phagocytosis. However, the role of Ly-GDI in inflammation remains largely unknown. In the current study, we found that Ly-GDI expression was significantly decreased in the IgG immune complex-injured lungs. To determine if Ly-GDI might regulate the lung inflammatory response, we constructed adenovirus vectors that could mediate ectopic expression of Ly-GDI (Adeno-Ly-GDI). In vivo mouse lung expression of Ly-GDI resulted in a significant attenuation of IgG immune complex-induced lung injury, which was due to the decreased pulmonary permeability and lung inflammatory cells, especially neutrophil accumulation. Upon IgG immune complex deposition, mice with Ly-GDI over-expression in the lungs produced significant less inflammatory mediators (TNF-α, IL-6, MCP-1, and MIP-1α) in bronchoalveolar lavage fluid when compared control mice receiving airway injection of Adeno-GFP. Mechanically, IgG immune complex-induced NF-κB activity was markedly suppressed by Ly-GDI in both alveolar macrophages and lungs as measured by luciferase assay and electrophoretic mobility shift assay. These findings suggest that Ly-GDI is a critical regulator of inflammatory injury after deposition of IgG immune complexes and that it negatively regulates the lung NF-κB activity.

  20. Comparing sizes of Lyα and UV emission of Green Pea galaxies

    Science.gov (United States)

    Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Jiang, Tianxing; Wang, JunXian

    2016-06-01

    We studied the spatial profiles of Lyα and UV emission from 16 Green Pea galaxies with Cosmic Origins Spectrograph (COS) data from the Hubble Space Telescope (HST). Green Pea galaxies are nearby analogs of high-z Lyα emitting galaxies. We extract the spatial profiles of Lyα emission from the 2D COS spectra of Green Peas. The Lyα emission shows more extended spatial profiles than the UV emissions in most galaxies in our sample. The intrinsic Lyα sizes (measured as the Full Width Half Maximum of intrinsic Lyα spatial profile) are about 2 to 5 times of the UV sizes (measured as the FWHM of UV image) in most cases. The Lyα emissions show large offsets from the UV emissions in three galaxies and double-horned spatial profile in one galaxy. We compare the spatial profiles of Lyα photons at different velocities and find a relation between Lyα velocity profile and spatial profile. These results suggest that most Lyα photons escape out of a galaxy through many resonant scatterings in the HI gas with low column density, instead of directly escaping through ionized holes in the interstellar medium.

  1. Lyman-\\alpha{} Emitters in the context of hierarchical galaxy formation: predictions for VLT/MUSE surveys

    CERN Document Server

    Garel, Thibault; Blaizot, Jérémy

    2015-01-01

    The VLT Multi Unit Spectroscopic Explorer (MUSE) integral-field spectrograph can detect Ly\\alpha{} emitters (LAE) in the redshift range $2.8 \\lesssim z \\lesssim 6.7$ in a homogeneous way. Ongoing MUSE surveys will notably probe faint Ly\\alpha{} sources that are usually missed by current narrow-band surveys. We provide quantitative predictions for a typical wedding-cake observing strategy with MUSE based on mock catalogs generated with a semi-analytic model of galaxy formation coupled to numerical Ly\\alpha{} radiation transfer models in gas outflows. We expect $\\approx$ 1500 bright LAEs ($F_{Ly\\alpha}$ $\\gtrsim$ $10^{-17}$ erg s$^{-1}$ cm$^{-2}$) in a typical Shallow Field (SF) survey carried over $\\approx$ 100 arcmin$^2$, and $\\approx$ 2,000 sources as faint as $10^{-18}$ erg s$^{-1}$ cm$^{-2}$ in a Medium-Deep Field (MDF) survey over 10 arcmin$^2$. In a typical Deep Field (DF) survey of 1 arcmin$^2$, we predict that $\\approx$ 500 extremely faint LAEs ($F_{Ly\\alpha}$ $\\gtrsim$ $4 \\times 10^{-19}$ erg s$^{-1}$...

  2. The Stacked Lyman-Alpha Emission Profile from the Circum-Galactic Medium of z~2 Quasars

    CERN Document Server

    Battaia, Fabrizio Arrigoni; Cantalupo, Sebastiano; Prochaska, J Xavier

    2016-01-01

    In the context of the FLASHLIGHT survey, we obtained deep narrow band images of 15 $z\\sim2$ quasars with GMOS on Gemini-South in an effort to measure Ly$\\alpha$ emission from circum- and inter-galactic gas on scales of hundreds of kpc from the central quasar. We do not detect bright giant Ly$\\alpha$ nebulae (SB~10$^{-17}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ at distances >50 kpc) around any of our sources, although we routinely ($\\simeq47$%) detect smaller scale <50 kpc Ly$\\alpha$ emission at this SB level emerging from either the extended narrow emission line regions powered by the quasars or by star-formation in their host galaxies. We stack our 15 deep images to study the average extended Ly$\\alpha$ surface brightness profile around $z\\sim2$ quasars, carefully PSF-subtracting the unresolved emission component and paying close attention to sources of systematic error. Our analysis, which achieves an unprecedented depth, reveals a surface brightness of SB$_{\\rm Ly\\alpha}\\sim10^{-19}$ erg s$^{-1}$ cm$^{-2}...

  3. Changing Traditions and Village Development in Kalotaszentkirály

    Directory of Open Access Journals (Sweden)

    Wayne Kraft

    2011-10-01

    Full Text Available The continuity of village traditions depends on the stability and cohesion of village communities. Since the opening of Transylvania after the fall of Nicolae Ceauşescu, there has been a sort of revival of Hungarian village dance and music, on the one hand, but, on the longer term, the communities themselves are threatened by economic challenges and by consequent demographic changes. This essay is based on field research conducted in Kalotaszentkirály (Sincraiu from 1995 to 2010.

  4. LY294002 induces p53-dependent apoptosis of SGC7901 gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Chun-gen XING; Bao-song ZHU; Hui-hui LIU; Fang LIN; Hui-hua YAO; Zhong-qin LIANG; Zheng-hong QIN

    2008-01-01

    Aim:To study the effects of LY294002, an inhibitor of class Ⅰ phosphatidylinositol 3-kinase (PI3K), on proliferation and apoptosis of SGC7901 gastric cancer cells. Methods:The MTT assay was used to determine the cytotoxic effects of LY294002. Cell cycle distribution was analyzed using flow cytometry and apoptosis was assessed using flow cytometry analysis after staining DNA with propidium iodide. Mitochondrial membrane potential was measured using the fluorescent probe JC-1. Expression of p53 and PUMA was determined using real-time RT-PCR and West-ern blotting analysis. Results:The viability of SGC7901 cells was significantly reduced by LY294002 treatment. Expression of p53 and PUMA was induced, and mitochondrial membrane potential collapsed after treatment with LY294002. LY294002 induced apoptotic cell death. Conclusion:Activation of the p53 path-way is involved in LY294002-induced SGC7901 cell death.

  5. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F.Lu; Q.P.Zhong; 等

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) and LY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements.Open circuit potential elec-trochemical measurements showed a relatively large potemtial difference about 1 volt between the GECM and LY12CZ aluminum alloy,and this difference provided the driving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode. Having been exposed for 1,3or 5years in Beijing,Tuandao and Wanning station,GECM/LY12CZ couples showed significant losses of strength and elongation.Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions.Epoxy primer paint,glass cloth barriers and LY12CZ anodizing were effective in glvanic corrosion control for GECM/LY12CZ couples.

  6. Alpha Blockers

    Science.gov (United States)

    ... positive side, alpha blockers might decrease low-density lipoprotein (LDL) cholesterol (the "bad" cholesterol). Alpha blockers can ... PreventionTreatmentofHighBloodPressure/Types-of-Blood-Pressure-Medications_UCM_303247_Article.jsp. Accessed June 4, 2016. Kaplan NM, et ...

  7. About AGN ionization echoes, thermal echoes, and ionization deficits in low redshift Lyman-alpha blobs

    CERN Document Server

    Schirmer, Mischa; Levenson, Nancy A; Fu, Hai; Davies, Rebecca L; Keel, William C; Torrey, Paul; Bennert, Vardha N; Pancoast, Anna; Turner, James E H

    2016-01-01

    We report the discovery of 14 Lyman-alpha blobs (LABs) at z~0.3, existing at least 4-7 billion years later in the Universe than all other LABs known. Their optical diameters are 20-70 kpc, and GALEX data imply Ly-alpha luminosities of (0.4-6.3)x10^43 erg/s. Contrary to high-z LABs, they live in low-density areas. They are ionized by AGN, suggesting that cold accretion streams as a power source must deplete between z=2 and z=0.3. We also show that transient AGN naturally explain the ionization deficits observed in many LABs: Their Ly-alpha and X-ray fluxes decorrelate below 10^6 years because of the delayed escape of resonantly scattering Ly-alpha photons. High Ly-alpha luminosities do not require currently powerful AGN, independent of obscuration. Chandra X-ray data reveal intrinsically weak AGN, confirming the luminous optical nebulae as impressive ionization echoes. For the first time, we also report mid-infrared thermal echoes from the dusty tori. We conclude that the AGN have faded by 3-4 orders of magnit...

  8. From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy Medium

    CERN Document Server

    Gronke, Max; McCourt, Michael; Oh, S Peng

    2016-01-01

    Lyman-Alpha (Ly$\\alpha$) is the strongest emission line in the Universe and is frequently used to detect and study the most distant galaxies. Because Lya is a resonant line, photons typically scatter prior to escaping; this scattering process complicates the interpretation of Ly$\\alpha$ spectra, but also encodes a wealth of information about the structure and kinematics of neutral gas in the galaxy. Modeling the Ly$\\alpha$ line therefore allows us to study tiny-scale features of the gas, even in the most distant galaxies. Curiously, observed Ly$\\alpha$ spectra can be modeled successfully with very simple, homogeneous geometries (such as an expanding, spherical shell), whereas more realistic, multiphase geometries often fail to reproduce the observed spectra. This seems paradoxical since the gas in galaxies is known to be multiphase. In this Letter, we show that spectra emerging from extremely clumpy geometries with many clouds along the line of sight converge to the predictions from simplified, homogeneous mo...

  9. PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Vayner, Andrey; Wright, Shelley A. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Do, Tuan [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Larkin, James E. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Armus, Lee [Spitzer Science Center, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Gallagher, S. C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada)

    2016-04-10

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ∼ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ∼0.″2 (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (z{sub Hα} = 2.182) and SDSS J0925+0655 (z{sub Hα} = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M{sub ⊙} yr{sup −1} originating from a compact region that is kinematically offset by 290–350 km s{sup −1}. For SDSS J0925+0655 we infer a SFR of 29 M{sub ⊙} yr{sup −1} distributed over three clumps that are spatially offset by ∼7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M{sub ⊙} yr{sup −1} kpc{sup −2}. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M{sub ⊙} yr{sup −1} kpc{sup −2}. These IFS observations indicate that while the central black hole is accreting mass at 10%–40% of the Eddington rate, if

  10. The ESO key-programme "a homogeneous bright QSO survey"; 1, the methods and the "deep" fields

    CERN Document Server

    Cristiani, S; Andreani, P; Gemmo, A; Goldschmidt, P; Miller, L; Vio, R; Barbieri, C; Bodini, L; Iovino, A; Lazzarin, M; Clowes, R G; MacGillivray, H T; Gouiffes, C; Lissandrini, C; Savage, A

    1995-01-01

    This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range 15 < B < 18.75 and 0.3 < z < 2.2. The selection is carried out using direct plates obtained at the ESO and UK Schmidt Telescopes, scanned with the COSMOS facility and searched for objects with an ultraviolet excess. Follow-up spectroscopy, carried out at ESO La Silla, is used to classify each candidate. In this initial paper, we describe the scientific objectives of the survey; the selection and observing techniques used. We present the first sample of 285 QSOs (M_B < -23) in a 153 deg^2 area, covered by the six ``deep'' fields, intended to obtain significant statistics down B \\simeq 18.75 with unprecedented photometric accuracy. From this database, QSO counts are determined in the magnitude range 17 < B < 18.75.

  11. The ESO key-programme "A homogeneous bright QSO survey". I. The methods and the "deep" fields.

    Science.gov (United States)

    Cristiani, S.; La Franca, F.; Andreani, P.; Gemmo, A.; Goldschmidt, P.; Miller, L.; Vio, R.; Barbieri, C.; Bodini, L.; Iovino, A.; Lazzarin, M.; Clowes, R.; MacGillivray, H.; Gouiffes, C.; Lissandrini, C.; Savage, A.

    1995-09-01

    This is the first paper in a series aimed at defining a statistically significant sample of QSOs in the range 15QSO counts are determined in the magnitude range 17

  12. Kodály Approach in the Crossroad of Education and Therapy

    OpenAIRE

    Luca Tiszai

    2015-01-01

    Kodály's concept about music education is worldwide adapted to different cultures. However, the significance of his theoretical framework is almost undiscovered by music therapy. The aim of the present paper is to shed light on the common elements of Commuity Music Therapy and the Kodály Approach by literature-based Research. Kodály was a pioneer establishing a multidisciplinary dialog between musicology, philosophy, sociology and education. The practice and theory he established was a powerf...

  13. Detecting Damped Lyman-$\\alpha$ Absorbers with Gaussian Processes

    CERN Document Server

    Garnett, Roman; Bird, Simeon; Schneider, Jeff

    2016-01-01

    We develop an automated technique for detecting damped Lyman-$\\alpha$ absorbers (DLAs) along spectroscopic sightlines to quasi-stellar objects (QSOs or quasars). The detection of DLAs in large-scale spectroscopic surveys such as SDSS-III sheds light on galaxy formation at high redshift, showing the nucleation of galaxies from diffuse gas. We use nearly 50 000 QSO spectra to learn a novel tailored Gaussian process model for quasar emission spectra, which we apply to the DLA detection problem via Bayesian model selection. We propose models for identifying an arbitrary number of DLAs along a given line of sight. We demonstrate our method's effectiveness using a large-scale validation experiment, with excellent performance. We also provide a catalog of our results applied to 162 861 spectra from SDSS-III data release 12.

  14. The Green Peas: Searching for LyC Emitters at Low Redshift

    Science.gov (United States)

    Jaskot, Anne; Oey, Sally

    The escape fraction of Lyman continuum (LyC) radiation from galaxies remains one of the primary uncertainties in studies of reionization. However, few LyC-emitting galaxies are known. The recently identified, low-redshift ``Green Pea'' (GP) galaxies exhibit a number of similarities with high-redshift galaxies, and their optical emission lines suggest they may be some of the elusive LyC emitters. Recent HST COS and ACS observations of four GPs suggest further evidence for LyC escape and give new insights into the origins of Lyα and low-ionization UV lines in high-redshift galaxies. The Lyα emission and low-ionization emission and absorption lines provide a coherent physical picture of the neutral gas distribution in the GPs and may identify LyC emitters at high redshift. The rare, low-redshift GPs hint at possible factors that may enable LyC and Lyα escape from high-redshift galaxies.

  15. Effect of Anneal on the Release Behaviour of LY12-Al Alloy

    Institute of Scientific and Technical Information of China (English)

    HU Jian-Bo; YU Yu-Ying; TAN Hua; DAI Cheng-Da

    2006-01-01

    @@ The sound velocities along the release path of annealed LY12-Al are measured by using a velocity interferometer system for any reflector (VISAR) technique. The shear modulus and yield strength are then obtained. Comparison of the experimental results with those of unannealed LY12-Al shows that anneal has little influence on sound velocities and shear modulus though it weakens the yield strength considerably, and changes the dependence of yield strength upon shock stress. The ratio of shear modulus to yield strength of unannealed LY12-Al increases with shock stress monotonically while that of annealed LY12-Al exhibits much more complicated behaviour.

  16. Phase I clinical and pharmacokinetic study of LY 195448.

    Science.gov (United States)

    Cassidy, J; Lewis, C; Adams, L; Setanoians, A; Bayssas, M; Boder, G G; Rankin, E M; Kaye, S B

    1989-01-01

    LY 195448 is a phenethanolamine that has shown anti-tumour activity in a range of murine tumour models, although its mechanism of action is unknown. Pre-clinical studies have indicated the absence of "standard" side effects such as myelosuppression and gastrointestinal toxicity. The present phase I trial was carried out in nine patients at doses ranging up to 133 mg/m2. The major toxicities up to that dose were mild, reversible hypotension, tachycardia and tremor. No haematological or biochemical toxicity was observed. Murine pharmacokinetics were assessed at a dose level that was effective in experimental tumours and compared with human pharmacokinetic parameters derived from this study. The results indicated the clinical possibility of reaching peak drug levels associated with experimental activity. However, no responses were seen at the doses used. This study was terminated prior to its completion due to an unexplained loss of activity against murine tumours since September 1987. No significant loss of the in vitro anti-mitotic activity originally reported by Boder et al. [3] was observed. Possible reasons for the apparent loss of in vivo activity have been intensively investigated, but no cause has been determined. Therefore, clinical trials with LY 195448 have been discontinued.

  17. Lenses in the forest: cross--correlation of the Lyman-alpha flux with CMB lensing

    Energy Technology Data Exchange (ETDEWEB)

    Vallinotto, Alberto; /Paris, Inst. Astrophys. /Fermilab; Das, Sudeep; /Princeton U. Observ. /Princeton U.; Spergel, David N.; /Princeton U. Observ. /APC, Paris; Viel, Matteo; /Trieste Observ. /INFN, Trieste

    2009-03-01

    We present a theoretical estimate for a new observable: the cross-correlation between the Lyman-{alpha}-flux fluctuations in quasar (QSO) spectra and the convergence of the cosmic microwave background (CMB) as measured along the same line-of-sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line-of-sight and peaks at somewhat smaller redshifts than those probed by the Lyman-{alpha} forest, we estimate a total signal-to-noise of 9 for cross-correlating QSO spectra of SDSSIII with Planck and 20 for cross-correlating with a future polarization based CMB experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross-correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed by observations.

  18. Clustering and lifetime of Lyman Alpha Emitters in the Epoch of Reionization

    CERN Document Server

    Hutter, Anne; Müller, Volker

    2015-01-01

    We calculate Lyman Alpha Emitter (LAE) angular correlation functions (ACFs) at $z\\simeq6.6$ and the fraction of lifetime (for the 100 Myrs preceding $z\\simeq6.6$) galaxies spend as Lyman Break Galaxies (LBGs) with/without Lyman Alpha (Ly\\alpha) emission using a model that combines SPH cosmological simulations (GADGET-2), dust attenuation and a radiative transfer code (pCRASH). The ACFs are a powerful tool that significantly narrows the 3D parameter space allowed by LAE Ly$\\alpha$ and UV luminosity functions (LFs) alone. With this work, we simultaneously constrain the escape fraction of ionizing photons $f_{esc}=0.05-0.5$, the mean fraction of neutral hydrogen in the intergalactic medium (IGM) $\\leq 0.01$ and the dust-dependent ratio of the escape fractions of Ly$\\alpha$ and UV continuum photons $f_\\alpha/f_c=0.6-1.2$. Our results show that reionization has the largest impact on the amplitude of the ACFs, and its imprints are clearly distinguishable from those of $f_{esc}$ and $f_\\alpha/f_c$. We also show that...

  19. Alpha fetoprotein

    Science.gov (United States)

    Fetal alpha globulin; AFP ... Greater than normal levels of AFP may be due to: Cancer in testes , ovaries, biliary (liver secretion) tract, stomach, or pancreas Cirrhosis of the liver Liver cancer ...

  20. Jovian Equatorial H Lyman-alpha and the Ionosphere

    Science.gov (United States)

    Ballester, Gilda E.

    An excess of H Ly alpha emission has been a persistent feature in Jupiter's equatorial upper atmosphere since its discovery in 1978. This Ly alpha 'bulge' was found by high-resolution IUE observations to be due to broadening of the Jovian line increasing the resonant scattering of the solar Ly alpha, rather than from a local enhancement in the H density. The line broadening implies that the H column at the bulge is disturbed by a localized, non-thermal process, and two mechanisms have been proposed to explain this: one by the generation of turbulence from strong thermospheric winds or jets meeting at the bulge region and originating in the active Jovian auroral zones, the other involving a superthermal population of H atoms produced by a process analogous to the equatorial anomaly and tropical arcs on the Earth. Some line broadening was also observed in the off-bulge region while modelling of the usual bulge profile does not predict this behavior, but these observations may have been performed at a time of an unusually large extension of the bulge. We propose to make a series of high-dispersion observations (of improved S/N) for a detailed longitudinal study of the line profile which would be of benefit independently of the particular bulge conditions (to be determined with low-dispersion exposures). In addition, new insight will be gained with simultaneous ground-based observations of the newly discovered global ionospheric H3+ emissions. These emissions are diagnostic of the ionospheric temperature and ion density, and have already shown very particular characteristics in the H Ly alpha bulge region. Coordinated observations of the whole longitudinal range should therefore set new constraints on the mechanisms operating in the Jovian equatorial upper atmosphere.

  1. Possible evidence for a variable fine structure constant from QSO absorption lines systematic errors

    CERN Document Server

    Murphy, M T; Flambaum, V V; Churchill, C W; Prochaska, J X

    2001-01-01

    Comparison of quasar absorption spectra with laboratory spectra allow us to probe possible variations in the fundamental constants over cosmological time-scales. In a companion paper we present an analysis of Keck/HIRES spectra and report possible evidence suggesting that the fine structure constant, alpha, may have been smaller in the past: da/a = (-0.72 +/- 0.18) * 10^{-5} over the redshift range 0.5 < z < 3.5. In this paper we describe a comprehensive investigation into possible systematic effects. Most of these do not significantly influence our results. When we correct for those which do produce a significant systematic effect in the data, the deviation of da/a from zero becomes more significant. We are lead increasingly to the interpretation that alpha was slightly smaller in the past.

  2. Anne-Ly Võlli: Iga inimene ja asutus vajab omamoodi lähenemist / Anne-Ly Võlli ; intervjueerinud Jaanika Kressa

    Index Scriptorium Estoniae

    Võlli, Anne-Ly, 1976-

    2009-01-01

    MTÜ Jõgevamaa Omavalitsuste Aktiviseerimiskeskus kinnitas avaliku konkursi tulemusel juhatuse liikmeks Anne-Ly Võlli, kelle ülesandeks on keskuse tegevuse juhtimine ja koostöö arendamine partneromavalitsuste ja teiste koostööpartnerite vahel

  3. Anne-Ly Võlli: Iga inimene ja asutus vajab omamoodi lähenemist / Anne-Ly Võlli ; intervjueerinud Jaanika Kressa

    Index Scriptorium Estoniae

    Võlli, Anne-Ly, 1976-

    2009-01-01

    MTÜ Jõgevamaa Omavalitsuste Aktiviseerimiskeskus kinnitas avaliku konkursi tulemusel juhatuse liikmeks Anne-Ly Võlli, kelle ülesandeks on keskuse tegevuse juhtimine ja koostöö arendamine partneromavalitsuste ja teiste koostööpartnerite vahel

  4. Possible evidence for a variable fine structure constant from QSO absorption lines motivations, analysis and results

    CERN Document Server

    Murphy, M T; Flambaum, V V; Dzuba, V A; Churchill, C W; Prochaska, J X; Barrow, John D; Wolfe, A M

    2001-01-01

    An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratory spectra provides a sensitive probe for variability of the fine structure constant, alpha, over cosmological time-scales. We have previously developed and applied a new method providing an order of magnitude gain in precision over previous optical astrophysical constraints. Here we extend that work by including new quasar spectra of damped Lyman-alpha absorption systems. We also re-analyse our previous lower redshift data and confirm our initial results. The constraints on alpha come from simultaneous fitting of absorption lines of subsets of the following species: Mg I, Mg II, Al II, Al III, Si II, Cr II, Fe II, Ni II and Zn II. We present a detailed description of our methods and results based on an analysis of 49 quasar absorption systems (towards 28 QSOs) covering the redshift range 0.5 < z < 3.5. There is...

  5. A CORRELATION BETWEEN Lyα SPECTRAL LINE PROFILE AND REST-FRAME UV MORPHOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Vivian U; Hemmati, Shoubaneh; Darvish, Behnam; Mobasher, Bahram; Nayyeri, Hooshang; Mallery, Ryan [Department of Physics and Astronomy, University of California, Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Dickinson, Mark [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Spinrad, Hyron, E-mail: vivianu@ucr.edu [Department of Astronomy, University of California, Berkeley, CA 94720 (United States)

    2015-12-10

    We explore the relationship between the spectral shape of the Lyα emission and the UV morphology of the host galaxy using a sample of 304 Lyα-emitting BVi-dropouts at 3 < z < 7 in the Great Observatories Origins Deep Survey and Cosmic Evolution Survey fields. Using our extensive reservoir of high-quality Keck DEIMOS spectra combined with Hubble Space Telescope WFC3 data, we measure the Lyα line asymmetries for individual galaxies and compare them to axial ratios measured from observed J- and H-band (restframe UV) images. We find that the Lyα skewness exhibits a large scatter at small elongation (a/b < 2), and this scatter decreases as the axial ratio increases. Comparison of this trend to radiative transfer models and various results from the literature suggests that these high-redshift Lyα emitters are not likely to be intrinsically round and symmetric disks, but they probably host galactic outflows traced by Lyα emitting clouds. The ionizing sources are centrally located, and the optical depth is a good indicator of the absorption and scattering events on the escape path of Lyα photons from the source. Our results find no evidence of evolution in Lyα asymmetry or axial ratio with look-back time.

  6. The dynamical masses, densities, and star formation scaling relations of Lyα galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Rhoads, James E.; Malhotra, Sangeeta; Richardson, Mark L. A.; McLinden, Emily M. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Finkelstein, Steven L. [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States); Fynbo, Johan P. U. [DARK Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Tilvi, Vithal S., E-mail: James.Rhoads@asu.edu [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics, Texas A and M University, College Station, TX 77843 (United States)

    2014-01-01

    We present the first dynamical mass measurements for Lyα galaxies at high redshift, based on velocity dispersion measurements from rest-frame optical emission lines and size measurements from Hubble Space Telescope imaging, for nine galaxies drawn from four surveys. We use these measurements to study Lyα galaxies in the context of galaxy scaling relations. The resulting dynamical masses range from 10{sup 9} to 10{sup 10} M {sub ☉}. We also fit stellar population models to our sample and use them to place the Lyα sample on a stellar mass versus line width relation. The Lyα galaxies generally follow the same scaling relation as star-forming galaxies at lower redshift, although, lower stellar mass fits are also acceptable in ∼1/3 of the Lyα galaxies. Using the dynamical masses as an upper limit on gas mass, we show that Lyα galaxies have unusually active star formation for their gas mass surface density. This behavior is consistent with what is observed in starburst galaxies, despite the typically smaller masses and sizes of the Lyα galaxy population. Finally, we examine the mass densities of these galaxies and show that their future evolution likely requires dissipational ('wet') merging. In short, we find that Lyα galaxies are low-mass cousins of larger starbursts.

  7. Evolution of Ly Forest in Redshift Range 0.5 < < 3.4

    Indian Academy of Sciences (India)

    G. Q. Li; Z. F. Chen; Y. T. Zhou

    2014-09-01

    We collect 23 spectral data from literature, which is regarded as a relatively sufficient sample. The evolution index was calculated to study the evolution of Ly line density of Ly forest. This paper discusses the relationship between the evolution with the redshift in different interval threshold of column density. The results are in accordance with the results of previous research.

  8. Hydrogen Lyman-alpha and Lyman-beta radiances and profiles in polar coronal holes

    CERN Document Server

    Tian, Hui; Curdt, Werner; Vial, Jean-Claude

    2009-01-01

    The hydrogen Lyman-alpha plays a dominant role in the radiative energy transport in the lower transition region, and is important for the stud- ies of transition-region structure as well as solar wind origin. We investigate the Ly-alpha profiles obtained by SUMER in coronal holes and quiet Sun. In a subset of these observations, also the Hi Lyman-beta, Si iii, and O vi lines were (quasi-) simultaneously recorded. We find that the distances between the two peaks of Ly-alpha profiles are larger in coronal holes than in the quiet Sun, indicating a larger opacity in coronal holes. This difference might result from the different magnetic structures or the different radiation fields in the two regions. Most of the Ly-beta profiles in the coronal hole have a stronger blue peak, in contrast to those in quiet-Sun regions. Whilst in both regions the Ly-alpha profiles are stronger in the blue peak. Although the asymmetries are likely to be produced by differential flows in the solar atmosphere, their detailed formation ...

  9. C IV and He II Line Emission of Lyman Alpha Blobs: Powered by Shock Heated Gas

    CERN Document Server

    Cabot, Samuel H C; Zheng, Zheng

    2016-01-01

    Utilizing {\\it ab initio} ultra-high resolution hydrodynamical simulations, we investigate the properties of the interstellar and circum-galactic medium of Ly$\\alpha$ Blobs (LABs) at $z=3$, focusing on three important emission lines: Ly$\\alpha$ 1216\\AA, \\heii 1640\\AA\\ and \\civ 1449\\AA. Their relative strengths provide a powerful probe of the thermodynamic properties of the gas when confronted with observations. By adjusting the dust attenuation effect using one parameter and matching the observed size-luminosity relation of LABs using another parameter, we show that our simulations can reproduce the observed \\civ/\\lya\\ and \\heii/\\lya\\ ratios adequately. This analysis provides the first successful physical model to account for simultaneously the LAB luminosity function, luminosity-size relation, and the \\civ/Ly$\\alpha$ and \\heii/Ly$\\alpha$ ratios, with only two parameters. The physical underpinning for this model is that, in addition to the stellar component for the \\lya\\ emission, the \\lya\\ and \\civ\\ emission...

  10. Extinction Correction Significantly Influences the Estimate of the Lyα Escape Fraction

    Science.gov (United States)

    An, Fang Xia; Zheng, Xian Zhong; Hao, Cai-Na; Huang, Jia-Sheng; Xia, Xiao-Yang

    2017-02-01

    The Lyα escape fraction is a key measure to constrain the neutral state of the intergalactic medium and then to understand how the universe was fully reionized. We combine deep narrowband imaging data from the custom-made filter NB393 and the {{{H}}}2S1 filter centered at 2.14 μm to examine the Lyα emitters and Hα emitters at the same redshift z = 2.24. The combination of these two populations allows us to determine the Lyα escape fraction at z = 2.24. Over an area of 383 arcmin2 in the Extended Chandra Deep Field South (ECDFS), 124 Lyα emitters are detected down to NB393 = 26.4 mag at the 5σ level, and 56 Hα emitters come from An et al. Of these, four have both Lyα and Hα emissions (LAHAEs). We also collect the Lyα emitters and Hα emitters at z = 2.24 in the COSMOS field from the literature, and increase the number of LAHAEs to 15 in total. About one-third of them are AGNs. We measure the individual/volumetric Lyα escape fraction by comparing the observed Lyα luminosity/luminosity density to the extinction-corrected Hα luminosity/luminosity density. We revisit the extinction correction for Hα emitters using the Galactic extinction law with color excess for nebular emission. We also adopt the Calzetti extinction law together with an identical color excess for stellar and nebular regions to explore how the uncertainties in extinction correction affect the estimate of individual and global Lyα escape fractions. In both cases, an anti-correlation between the Lyα escape fraction and dust attenuation is found among the LAHAEs, suggesting that dust absorption is responsible for the suppression of the escaping Lyα photons. However, the estimated Lyα escape fraction of individual LAHAEs varies by up to ∼3 percentage points between the two methods of extinction correction. We find the global Lyα escape fraction at z = 2.24 to be (3.7 ± 1.4)% in the ECDFS. The variation in the color excess of the extinction causes a discrepancy of ∼1 percentage

  11. The low-metallicity QSO HE 2158-0107: A massive galaxy growing by the accretion of nearly pristine gas from its environment?

    CERN Document Server

    Husemann, B; Jahnke, K; Sánchez, S F

    2011-01-01

    [abridged] The metallicities of AGN are usually well above solar in their NLR, often reaching up to several times solar in their broad-line regions. Low-metallicity AGN are rare objects which have so far always been associated with low-mass galaxies hosting low-mass BHs (M_BH<10^6Msun). In this paper we present IFS data of the low-redshift QSO HE 2158-0107 for which we find strong evidence for sub-solar NLR metallicities associated with a massive BH (M_BH~3x10^8Msun). The QSO is surrounded by a large extended emission-line region reaching out to 30kpc from the QSO in a tail-like geometry. We present optical and near-IR images and investigate the properties of the host galaxy. The SED of the host is rather blue, indicative of a significant young age stellar population formed within the last 1Gyr. A 3sigma upper limit of L_bulge<4.5x10^10Lsun for the H band luminosity and a corresponding stellar mass upper limit of M_bulge<3.4x10^10Msun show that the host is offset from the local BH-bulge relations. Th...

  12. Ly-6A is required for T cell receptor expression and protein tyrosine kinase fyn activity.

    Science.gov (United States)

    Lee, S K; Su, B; Maher, S E; Bothwell, A L

    1994-05-01

    To characterize the function of the Ly-6A antigen in T cell activation, antisense Ly-6 RNA was expressed in a stably transfected antigen-specific T cell clone. Reduced Ly-6A expression results in inhibition of responses to antigen, anti-TCR (anti-T cell receptor) crosslinking and concanavalin A plus recombinant interleukin 1 and causes impairment of in vitro fyn tyrosine kinase activity. More substantial reduction of Ly-6A results in reduction of TCR expression. Analysis of mRNA species indicates that the reduction is specific for the TCR beta chain. These data demonstrate that Ly-6A may regulate TCR expression and may be involved in early events of T cell activation via regulation of fyn tyrosine kinase activity.

  13. Protective Role of Rho Guanosine Diphosphate Dissociation Inhibitor, Ly-GDI, in Pulmonary Alveolitis.

    Directory of Open Access Journals (Sweden)

    Chunguang Yan

    Full Text Available Growing evidences indicate that Ly-GDI, an inhibitory protein of Rho GTPases, plays an essential role in regulating actin cytoskeletal alteration which is indispensible for the process such as phagocytosis. However, the role of Ly-GDI in inflammation remains largely unknown. In the current study, we found that Ly-GDI expression was significantly decreased in the IgG immune complex-injured lungs. To determine if Ly-GDI might regulate the lung inflammatory response, we constructed adenovirus vectors that could mediate ectopic expression of Ly-GDI (Adeno-Ly-GDI. In vivo mouse lung expression of Ly-GDI resulted in a significant attenuation of IgG immune complex-induced lung injury, which was due to the decreased pulmonary permeability and lung inflammatory cells, especially neutrophil accumulation. Upon IgG immune complex deposition, mice with Ly-GDI over-expression in the lungs produced significant less inflammatory mediators (TNF-α, IL-6, MCP-1, and MIP-1α in bronchoalveolar lavage fluid when compared control mice receiving airway injection of Adeno-GFP. Mechanically, IgG immune complex-induced NF-κB activity was markedly suppressed by Ly-GDI in both alveolar macrophages and lungs as measured by luciferase assay and electrophoretic mobility shift assay. These findings suggest that Ly-GDI is a critical regulator of inflammatory injury after deposition of IgG immune complexes and that it negatively regulates the lung NF-κB activity.

  14. Detection of Lyman-Alpha Emission From a Triple Imaged z=6.85 Galaxy Behind MACS J2129.4-0741

    CERN Document Server

    Huang, Kuang-Han; Schmidt, Kasper B; Hoag, Austin; Bradač, Maruša; Treu, Tommaso; Dijkstra, Mark; Fontana, Adriano; Henry, Alaina; Malkan, Matthew; Mason, Charlotte; Morishita, Takahiro; Pentericci, Laura; Ryan, Russell E; Trenti, Michele; Wang, Xin

    2016-01-01

    We report the detection of Ly$\\alpha$ emission at $\\sim9538$\\AA{} in the Keck/DEIMOS and \\HST WFC3 G102 grism data from a triply-imaged galaxy at $z=6.846\\pm0.001$ behind galaxy cluster MACS J2129.4$-$0741. Combining the emission line wavelength with broadband photometry, line ratio upper limits, and lens modeling, we rule out the scenario that this emission line is \\oii at $z=1.57$. After accounting for magnification, we calculate the weighted average of the intrinsic Ly$\\alpha$ luminosity to be $\\sim1.3\\times10^{42}~\\mathrm{erg}~\\mathrm{s}^{-1}$ and Ly$\\alpha$ equivalent width to be $74\\pm15$\\AA{}. Its intrinsic UV absolute magnitude at 1600\\AA{} is $-18.6\\pm0.2$ mag and stellar mass $(1.5\\pm0.3)\\times10^{7}~M_{\\odot}$, making it one of the faintest (intrinsic $L_{UV}\\sim0.14~L_{UV}^*$) galaxies with Ly$\\alpha$ detection at $z\\sim7$ to date. Its stellar mass is in the typical range for the galaxies thought to dominate the reionization photon budget at $z\\gtrsim7$; the inferred Ly$\\alpha$ escape fraction is ...

  15. Keck/MOSFIRE Spectroscopy of z=7-8 Galaxies: Lyman-alpha Emission from a Galaxy at z=7.66

    CERN Document Server

    Song, Mimi; Livermore, Rachael C; Capak, Peter L; Dickinson, Mark; Fontana, Adriano

    2016-01-01

    We report the results from some of the deepest Keck/MOSFIRE data yet obtained for candidate $z \\gtrsim 7$ galaxies. Our data show one significant line detection with 6.5$\\sigma$ significance in our combined 10 hours of integration which is independently detected on more than one night, ruling out the possibility that the detection is spurious. The asymmetric line profile and non-detection in the optical bands strongly imply that the detected line is Ly$\\alpha$ emission from a galaxy at $z$(Ly$\\alpha)=7.6637 \\pm 0.0011$, making it the fourth spectroscopically confirmed galaxy at $z>7.5$. This galaxy is bright in the rest-frame ultraviolet (UV; $M_{\\rm UV} \\sim -21.2$) with a moderately blue UV slope ($\\beta=-2.2^{+0.3}_{-0.2}$), and exhibits a rest-frame Ly$\\alpha$ equivalent width of EW(Ly$\\alpha$) $\\sim 15.6^{+5.6}_{-3.6}$ \\AA. The non-detection of the 11 other $z \\sim$ 7--8 galaxies in our long 10 hr integration, reaching a median 5$\\sigma$ sensitivity of 28 \\AA\\ in the rest-frame EW(Ly$\\alpha$), implies a ...

  16. $\\alpha_s$ review (2016)

    CERN Document Server

    d'Enterria, David

    2016-01-01

    The current world-average of the strong coupling at the Z pole mass, $\\alpha_s(m^2_{Z}) = 0.1181 \\pm 0.0013$, is obtained from a comparison of perturbative QCD calculations computed, at least, at next-to-next-to-leading-order accuracy, to a set of 6 groups of experimental observables: (i) lattice QCD "data", (ii) $\\tau$ hadronic decays, (iii) proton structure functions, (iv) event shapes and jet rates in $e^+e^-$ collisions, (v) Z boson hadronic decays, and (vi) top-quark cross sections in p-p collisions. In addition, at least 8 other $\\alpha_s$ extractions, usually with a lower level of theoretical and/or experimental precision today, have been proposed: pion, $\\Upsilon$, W hadronic decays; soft and hard fragmentation functions; jets cross sections in pp, e-p and $\\gamma$-p collisions; and photon F$_2$ structure function in $\\gamma\\,\\gamma$ collisions. These 14 $\\alpha_s$ determinations are reviewed, and the perspectives of reduction of their present uncertainties are discussed.

  17. Lyman-Alpha Emitter Galaxies at z ~ 2.8 in the Extended Chandra Deep Field-South: I. Tracing the Large-Scale Structure via Lyman-Alpha Imaging

    CERN Document Server

    Zheng, Zhen-Ya; Rhoads, James E; Finkelstein, Steven L; Wang, Jun-Xian; Jiang, Chun-Yan; Cai, Zheng

    2016-01-01

    We present a narrowband survey with three adjacent filters for z=2.8--2.9 Lyman Alpha Emitter (LAE) galaxies in the Extended Chandra Deep Field South (ECDFS), along with spectroscopic followup. With a complete sample of 96 LAEs in the narrowband NB466, we confirm a large-scale structure at z~ 2.8. Compared to the blank field in NB470 and NB475, the LAE density excess in the NB466 field is ~6.0+/-0.8 times the standard deviation expected at z~2.8, assuming a linear bias of 2. The overdense large scale structure in NB466 can be decomposed into 4 protoclusters, whose overdensities are 4.6 - 6.6. These 4 protoclusters are expected to evolve into a Coma-like cluster at z~ 0. In the meanwhile, we investigate the average star-formation rates derived from Ly{\\alpha}, rest-frame UV and X-ray, the Ly{\\alpha} luminosity functions, the Ly{\\alpha} photon densities and their dependence on the environment. We find that the Ly{\\alpha} photon density in the overdense field (NB466) is ~50\\% higher than that in the blank field ...

  18. Myostatin antibody (LY2495655) in older weak fallers: a proof-of-concept, randomised, phase 2 trial

    Science.gov (United States)

    BACKGROUND: Myostatin inhibits skeletal muscle growth. The humanised monoclonal antibody LY2495655 (LY) binds and neutralises myostatin. We aimed to test whether LY increases appendicular lean body mass (aLBM) and improves physical performance in older individuals who have had recent falls and low m...

  19. XMM-Newton Spectroscopy of the X-ray Detected Broad Absorption Line QSO CSO 755

    Science.gov (United States)

    Brandt, Niel

    2005-01-01

    We present the results from XMM-Newton observations of the highly optically polarized broad absorption line quasar (BALQSO) CSO 755. By analyzing its X-ray spectrum with a total of approximately 3000 photons we find that this source has an X-ray continuum of "typical" radio-quiet quasars, with a photon index of Gamma=1.83, and a rather flat (X-ray bright) intrinsic optical-to-X-ray spectral slope of alpha_ox=- 1.51. The source shows evidence for intrinsic absorption, and fitting the spectrum with a neutral-absorption model gives a column density of N_H approximately 1.2x10^22 cm^{-2}; this is among the lowest X-ray columns measured for BALQSOs. We do not detect, with high significance, any other absorption features in the X-ray spectrum. Upper limits we place on the rest-frame equivalent width of a neutral (ionized) Fe K-alpha line, less than =180 eV (less than =120 eV), and on the Compton-reflection component parameter, R less than =0.2, suggest that most of the X-rays from the source are directly observed rather than being scattered or reflected; this is also supported by the relatively flat intrinsic alpha ox we measure. The possibility that most of the X-ray flux is scattered due to the high level of UV-optical polarization is ruled out. Considering data for 46 BALQSOs from the literature, including CSO 755, we have found that the UV-optical continuum polarization level of BALQSOs is not correlated with any of their X-ray properties. A lack of significant short-term and long-term X-ray flux variations in the source may be attributed to a large black-hole mass in CSO 755. We note that another luminous BALQSO, PG 2112+059, has both similar shallow C IV BALs and moderate X-ray absorption.

  20. A z ∼ 5.7 Lyα emission line with an ultrabroad red wing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Huan; Wang, JunXian [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, Zhen-Ya; Malhotra, Sangeeta; Rhoads, James E. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Infante, Leopoldo, E-mail: yanghuan@mail.ustc.edu.cn, E-mail: jxw@mail.ustc.edu.cn, E-mail: zzheng13@asu.edu, E-mail: smalhotr@asu.edu, E-mail: james.rhoads@asu.edu, E-mail: linfante@astro.puc.cl [Institute of Astrophysics, Ponticia Universidad Catolica, Santiago (Chile)

    2014-03-20

    Using the Lyα emission line as a tracer of high-redshift, star-forming galaxies, hundreds of Lyα emission line galaxies (LAEs) at z > 5 have been detected. These LAEs are considered to be low-mass young galaxies, critical to the re-ionization of the universe and the metal enrichment of the circumgalactic medium (CGM) and the intergalactic medium (IGM). It is assumed that outflows in LAEs can help both ionizing photons and Lyα photons escape from galaxies. However, we still know little about the outflows in high-redshift LAEs due to observational difficulties, especially at redshift >5. Models of Lyα radiative transfer predict asymmetric Lyα line profiles with broad red wings in LAEs with outflows. Here, we report a z ∼ 5.7 Lyα emission line with a broad red wing extending to >1000 km s{sup –1} relative to the peak of Lyα line, which has been detected in only a couple of z > 5 LAEs until now. If the broad red wing is ascribed to gas outflow instead of active galactic nucleus activity, the outflow velocity could be larger than the escape velocity (∼500 km s{sup –1}) of a typical halo mass of z ∼ 5.7 LAEs, which is consistent with the idea that outflows in LAEs disperse metals to CGM and IGM.

  1. Finding bright z ≥ 6.6 Ly α emitters with lensing: prospects for Euclid

    Science.gov (United States)

    Marchetti, L.; Serjeant, S.; Vaccari, M.

    2017-10-01

    We model the z ≥ 6.6 Ly α luminosity function to estimate the number of lensed high-z Ly α emitters that may be detected by the Euclid Deep Survey. To span the whole range of possible predictions, we exploit two Ly α luminosity function models and two strong gravitational lensing models from the literature. We show that the planned Euclid Deep Survey observing 40 deg2 over the 920-1850 nm wavelength range down to a flux limit of Flim = 5 × 10-17 erg s-1 cm-2 will enable us to find between ˜0.85 and ˜1.82 deg-2 lensed Ly α emitters at z ≥ 6.6 depending on the adopted Ly α luminosity function and strong gravitational lensing model. The obvious [O ii], [O iii] and H β contaminants of the Ly α lensed population will be identified with the help of Euclid's spectral resolving power, while the Square Kilometre Array (SKA) will enable the identification of the interloper population of H α emitters. By combining Euclid and the SKA, we will thus be able to identify, for the first time, a sample of ˜34 to ˜73 lensed Ly α emitters at z ≥ 6.6.

  2. Characterization and function of human Ly-6/uPAR molecules

    Directory of Open Access Journals (Sweden)

    Hyun Kyung Kong & Jong Hoon Park*

    2012-11-01

    Full Text Available Human Ly-6/uPAR molecules are a superfamily composed oftwo subfamilies; one is the membrane bound proteins with aGPI-anchor and the other are secreted proteins without theGPI-anchor. Ly-6/uPAR molecules have remarkable amino acidhomology through a distinctive 8-10 cysteine-rich domain thatis associated predominantly with O-linked glycans. Thesemolecules are encoded by multiple tightly linked genes locatedon Chr. 8q23, and have a conserved genomic organization.Ly-6/uPAR molecules have an interesting expression patternduring hematopoiesis and on specific tumors indicating thatLy-6/uPAR molecules are associated with development of theimmune system and carcinogenesis. Thus, Ly-6/uPAR moleculesare useful antigens for diagnostic and therapeutic targets.This review summarizes our understanding of human Ly-6/uPAR molecules with regard to molecular structure as well aswhat is known about their function in normal and malignanttissues and suggest Ly-6/uPAR molecules as target antigens forcancer immunotherapy.

  3. XMM observations of the narrow-line QSO PHL 1092: Detection of a high and variable soft component

    CERN Document Server

    Das-Gupta, S; Dewangan, G C; Dasgupta, Surajit

    2004-01-01

    We present results based on an XMM observation of the high luminosity narrow-line QSO PHL 1092 performed in 2003 January. The 0.3-10 keV spectrum is well described by a model which includes a power-law (gamma ~ 2.1) and two blackbody components (kT ~ 130 eV and kT ~50 eV). The soft X-ray excess emission is featureless and contributes ~80% to the total X-ray emission in the 0.3-10keV band. The most remarkable feature of the present observation is the detection of X-ray variability at very short time scales: the X-ray emission varied by 35% in about 5000 s. We find that this variability can be explained by assuming that the overall normalisation varied during the observation. This indicates that the X-ray emission arises from very close to the putative black hole: within a few Schwarzschild radius. Considering the high intrinsic luminosity (~2x10^45 erg/s) and the large inferred mass of the putative black hole (~1.6x10^8 M_sun), the observed time scale of variability indicates emission at close to Eddington lum...

  4. Close Separation Triple System QSO 1009-0252 with Discordant Redshifts: Is the Spectrum of One Component Blueshifted?

    Indian Academy of Sciences (India)

    D. Basu

    2009-09-01

    1009-0252 is a Quasi Stellar Object (QSO) with three components A, B, C. A, B are thought to be the result of gravitational lensing of one object, and A, C constitute a close pair with redshifts 2.74 and 1.62 respectively. Close separation pairs of QSOs with discordant redshifts have received special attention in recent years, probably because of the possibility that they may be physically associated, implying non-cosmological redshifts. Attempts have been made to explain their occurrences due to the effect of gravitational lensing. However, gravitational lensing has not offered a completely satisfactory explanation for this triplet. Furthermore, examination revealed some inadequacies and inconsistencies in the redshift identification of the observed lines in the component A. Observational results of 1009-0252 therefore remain puzzling.We propose an alternative explanation by suggesting that A, B actually constitute a close pair and C is an unrelated object in the field. We show that the observed spectrum of A can be interpreted as blueshifted. This implies that A, B are two separate objects, one (A) approaching us and the other (B) receding from us, and are not the result of gravitational lensing of a single object. The oppositely directed pair A, B may have been ejected due to the merger of two galaxies.

  5. The puzzling radio-loud QSO 3C 186: a gravitational wave recoiling black hole in a young radio source?

    CERN Document Server

    Chiaberge, M; Meyer, E T; Georganopoulos, M; Marinucci, A; Bianchi, S; Tremblay, G R; Hilbert, B; Kotyla, J P; Capetti, A; Baum, S A; Macchetto, F D; Miley, G; O'Dea, C P; Perlman, E S; Sparks, W B; Norman, C

    2016-01-01

    Context. Radio-loud AGNs with powerful relativistic jets are thought to be associated with rapidly spinning black holes (BHs). BH spin-up may result from a number of processes, including accretion of matter onto the BH itself, and catastrophic events such as BH-BH mergers. Aims. We study the intriguing properties of the powerful (L_bol ~ 10^47 erg/s) radio-loud quasar 3C 186. This object shows peculiar features both in the images and in the spectra. Methods. We utilize near-IR Hubble Space Telescope (HST) images to study the properties of the host galaxy, and HST UV and SDSS optical spectra to study the kinematics of the source. Chandra X-ray data are also used to better constrain the physical interpretation. Results. HST imaging shows that the active nucleus is offset by 1.3 +- 0.1 arcsec (i.e. ~11 kpc) with respect to the center of the host galaxy. Spectroscopic data show that the broad emission lines are offset by -2140 +-390 km/s with respect to the narrow lines. Velocity shifts are often seen in QSO spec...

  6. The metals-to-dust ratio to very low metallicities using GRB and QSO absorbers; extremely rapid dust formation

    CERN Document Server

    Zafar, Tayyaba

    2013-01-01

    Among the key parameters defining the ISM of galaxies is the fraction of the metals that are locked up in dust: the metals-to-dust ratio. This ratio bears not only on the ISM and its evolution, but particularly on the origin of cosmic dust. We combine extinction and abundance data from GRB afterglows, from QSO absorbers, as well as from galaxy-lensed QSOs, to determine the metals-to-dust ratios for lines-of-sight through a wide diversity of galaxies from blue, dwarf starbursts to massive ellipticals, across a vast range in redshift z=0.1-6.3, and nearly three orders of magnitude in column density and metal abundance. We thus determine the metals-to-dust ratio in a unique way, providing direct determinations of in situ gas and dust columns without recourse to assumptions with large uncertainties. We find that the metals-to-dust ratios in these systems are surprisingly close to the value for the local group (10^{21.3} cm-2 A_V mag-1), with a mean value of 10^{21.2} cm-2 A_V mag-1 and a standard deviation of 0.3...

  7. Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2

    CERN Document Server

    York, D G; Baugher, B; Brinkmann, J; Crotts, A P S; Hall, P B; Jenkins, E B; Khare, P; Kulkarni, V P; Kumar, A; Lauroesch, J T; Lundgren, B; Ménard, B; Rao, S; Richards, G T; Schneider, D P; Shanidze, N; Smith, T; Tumlinson, J; Turnshek, D A; Vanden Berk, Daniel E; Vanlandingham, J; Welty, D E; Yip, C W; Alsayyad, Yusra; Baugher, Britt; Berk, Daniel Vanden; Brinkmann, Jon; Crotts, Arlin P. S.; Hall, Patrick B.; Jenkins, Edward B.; Khare, Pushpa; Kulkarni, Varsha P.; Kumar, Abhishek; Lauroesch, James T.; Lundgren, Britt; Menard, Brice; Rao, Sandhya; Richards, Gordon T.; Schneider, Donald P.; Shanidze, Natela; Smith, Tristan; Tumlinson, Jason; Turnshek, David; Vanlandingham, Johnny; Welty, Daniel E.; Yip, Ching-Wa; York, Donald G.

    2006-01-01

    We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and the chemical abundances in the intervening absorbers. Normalized, composite spectra were derived, for abundance measurements, for the full sample and several sub-samples, chosen on the basis of the line strengths and other absorber and QSO properties. Average extinction curves were obtained for the sub-samples by comparing their geometric mean spectra with those of matching samples of QSOs without absorbers in their spectra. There is clear evidence for the presence of dust in the intervening absorbers. The 2175 A feature is not present in the extinction curves, for any of the sub-samples. The extinction curves are similar to the SMC extinction curve with a rising UV extinction below 2200 A. The absorber rest frame colour excess, E(B-V), derived from the extinction curves, depends on the absorber properties and ranges from <...

  8. The Diversity of Diffuse Lyα Nebulae around Star-forming Galaxies at High Redshift

    Science.gov (United States)

    Xue, Rui; Lee, Kyoung-Soo; Dey, Arjun; Reddy, Naveen; Hong, Sungryong; Prescott, Moire K. M.; Inami, Hanae; Jannuzi, Buell T.; Gonzalez, Anthony H.

    2017-03-01

    We report the detection of diffuse Lyα emission, or Lyα halos (LAHs), around star-forming galaxies at z ≈ 3.78 and 2.66 in the NOAO Deep Wide-Field Survey Boötes field. Our samples consist of a total of ∼1400 galaxies, within two separate regions containing spectroscopically confirmed galaxy overdensities. They provide a unique opportunity to investigate how the LAH characteristics vary with host galaxy large-scale environment and physical properties. We stack Lyα images of different samples defined by these properties and measure their median LAH sizes by decomposing the stacked Lyα radial profile into a compact galaxy-like and an extended halo-like component. We find that the exponential scale-length of LAHs depends on UV continuum and Lyα luminosities, but not on Lyα equivalent widths or galaxy overdensity parameters. The full samples, which are dominated by low UV-continuum luminosity Lyα emitters (M UV ≳ ‑21), exhibit LAH sizes of 5–6 kpc. However, the most UV- or Lyα-luminous galaxies have more extended halos with scale-lengths of 7–9 kpc. The stacked Lyα radial profiles decline more steeply than recent theoretical predictions that include the contributions from gravitational cooling of infalling gas and from low-level star formation in satellites. However, the LAH extent matches what one would expect for photons produced in the galaxy and then resonantly scattered by gas in an outflowing envelope. The observed trends of LAH sizes with host galaxy properties suggest that the physical conditions of the circumgalactic medium (covering fraction, H i column density, and outflow velocity) change with halo mass and/or star formation rates.

  9. Regulation of expression of two LY-6 family genes by intron retention and transcription induced chimerism

    Directory of Open Access Journals (Sweden)

    Mallya Meera

    2008-09-01

    Full Text Available Abstract Background Regulation of the expression of particular genes can rely on mechanisms that are different from classical transcriptional and translational control. The LY6G5B and LY6G6D genes encode LY-6 domain proteins, whose expression seems to be regulated in an original fashion, consisting of an intron retention event which generates, through an early premature stop codon, a non-coding transcript, preventing expression in most cell lines and tissues. Results The MHC LY-6 non-coding transcripts have shown to be stable and very abundant in the cell, and not subject to Nonsense Mediated Decay (NMD. This retention event appears not to be solely dependent on intron features, because in the case of LY6G5B, when the intron is inserted in the artificial context of a luciferase expression plasmid, it is fully spliced but strongly stabilises the resulting luciferase transcript. In addition, by quantitative PCR we found that the retained and spliced forms are differentially expressed in tissues indicating an active regulation of the non-coding transcript. EST database analysis revealed that these genes have an alternative expression pathway with the formation of Transcription Induced Chimeras (TIC. This data was confirmed by RT-PCR, revealing the presence of different transcripts that would encode the chimeric proteins CSNKβ-LY6G5B and G6F-LY6G6D, in which the LY-6 domain would join to a kinase domain and an Ig-like domain, respectively. Conclusion In conclusion, the LY6G5B and LY6G6D intron-retained transcripts are not subjected to NMD and are more abundant than the properly spliced forms. In addition, these genes form chimeric transcripts with their neighbouring same orientation 5' genes. Of interest is the fact that the 5' genes (CSNKβ or G6F undergo differential splicing only in the context of the chimera (CSNKβ-LY6G5B or G6F-LY6G6C and not on their own.

  10. Kodály-metodin hyödyntäminen instrumenttipedagogiikassa : Musiikki kuuluu kaikille

    OpenAIRE

    Kallioniemi, Anni

    2012-01-01

    Tässä opinnäytetyössä tarkastellaan Kodály-metodin keinojen ja välineiden soveltamista soittotuntitilanteissa. Kokemus musiikin teoriaopintojen ja soitonopetuksen irtautumisesta toisistaan antoi intoa opinnäytetyöhön perehtymiseen. Kodály-metodi on unkarilaisen musiikinopetuksen perusta. Tämä pedagoginen suuntaus antaa opettajille hyviä välineitä korkealaatuiseen musiikinopetukseen. Työn keskeistä aineistoa olivat Zoltán Kodályn ja muiden Kodály-pedagogien kirjoitukset sekä oppimateriaal...

  11. The Lyα reference sample. I. Survey outline and first results for Markarian 259

    Energy Technology Data Exchange (ETDEWEB)

    Östlin, Göran; Hayes, Matthew; Duval, Florent; Sandberg, Andreas; Rivera-Thorsen, Thøger; Marquart, Thomas; Adamo, Angela; Melinder, Jens; Guaita, Lucia; Micheva, Genoveva [Department of Astronomy, Stockholm University, Oscar Klein Centre, AlbaNova, Stockholm SE-106 91 (Sweden); Orlitová, Ivana [Observatoire de Genève, Université de Genève, Chemin des Maillettes 51, 1290 Versoix (Switzerland); Atek, Hakim [Laboratoire d' Astrophysique, Ecole Polytechnique Fédérale de Lausanne, Observatoire de Sauverny, CH-1290 Versoix (Switzerland); Cannon, John M.; Pardy, Stephen A. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Gruyters, Pieter [Department of Physics and Astronomy, Division of Astronomy and Space Physics, Uppsala University, Box 516, 75120 Uppsala (Sweden); Herenz, Edmund Christian [Leibniz-Institute for Astrophysics Potsdam (AIP), innoFSPEC, An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel [Institut d' Astrophysique Paris, 98bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Mas-Hesse, J. Miguel [Centro de Astrobiologa (CSIC-INTA), Departamento de Astrofsica, POB 78, E-28691, Villanueva de la Cañada (Spain); Otí-Floranes, Héctor [Instituto de Astronoma, Universidad Nacional Autnoma de Mxico, Apdo. Postal 106, Ensenada B. C. 22800 (Mexico); and others

    2014-12-10

    The Lyα Reference Sample (LARS) is a substantial program with the Hubble Space Telescope (HST) that provides a sample of local universe laboratory galaxies in which to study the detailed astrophysics of the visibility and strength of the Lyαline of neutral hydrogen. Lyα is the dominant spectral line in use for characterizing high-redshift (z) galaxies. This paper presents an overview of the survey, its selection function, and HST imaging observations. The sample was selected from the combined GALEX+Sloan Digital Sky Survey catalog at z = 0.028-0.19, in order to allow Lyα to be captured with combinations of long-pass filters in the Solar Blind Channel (SBC) of the Advanced Camera for Surveys (ACS) onboard HST. In addition, LARS utilizes Hα and Hβ narrowband and u, b, i broadband imaging with ACS and the Wide Field Camera 3 (WFC3). In order to study galaxies in which large numbers of Lyα photons are produced (whether or not they escape), we demanded an Hα equivalent width W(Hα) ≥100 Å. The final sample of 14 galaxies covers far-UV (FUV, λ ∼ 1500 Å) luminosities that overlap with those of high-z Lyα emitters (LAEs) and Lyman break galaxies (LBGs), making LARS a valid comparison sample. We present the reduction steps used to obtain the Lyα images, including our LARS eXtraction software (LaXs), which utilizes pixel-by-pixel spectral synthesis fitting of the energy distribution to determine and subtract the continuum at Lyα. We demonstrate that the use of SBC long-pass-filter combinations increase the signal-to-noise ratio by an order of magnitude compared to the nominal Lyα filter available in SBC. To exemplify the science potential of LARS, we also present some first results for a single galaxy, Mrk 259 (LARS #1). This irregular galaxy shows bright and extended (indicative of resonance scattering) but strongly asymmetric Lyα emission. Spectroscopy from the Cosmic Origins Spectrograph on board HST centered on the brightest UV knot shows a moderate

  12. Properties of the observed Lyα forest

    Science.gov (United States)

    Demiański, M.; Doroshkevich, A. G.; Turchaninov, V.

    2000-11-01

    The main observed properties of Lyα absorbers are investigated on the basis of a theoretical model of formation and evolution of dark matter (DM) structure elements. This model is generally consistent with simulations of absorber formation and with the statistical description of structure evolution based on the Zel'dovich theory. The analysis of redshift variations of comoving linear number density of absorbers was performed in our previous paper. We show that the observed characteristics of the Doppler parameter can be related to the size of DM structure elements that allow us to explain the observed distribution of the Doppler parameter. This distribution is found to be consistent with the Gaussian initial perturbations. The observed characteristics of entropy and column density NHi confirm that the merging of pancakes is the main evolutionary process at redshifts z>=2. The observed sample of absorbers mainly characterizes the matter distribution within large low-density regions and therefore it is difficult to reconstruct the density field from the distribution of absorbers.

  13. Solar H-alpha features with hot onsets. III. Long fibrils in Lyman-alpha and with ALMA

    Science.gov (United States)

    Rutten, R. J.

    2017-02-01

    In H-alpha most of the solar surface is covered by dense canopies of long opaque fibrils, but predictions for quiet-Sun observations with ALMA have ignored this fact. Comparison with Ly-alpha suggests that the extraordinary opacity of H-alpha fibrils is caused by hot precursor events. Application of a recipe that assumes momentary Saha-Boltzmann extinction during their hot onset to millimeter wavelengths suggests that ALMA will observe H-alpha-like fibril canopies, not acoustic shocks underneath, and will yield data more interesting than if these canopies were transparent. An additional file is available at the end of the PDF file of this article.This study is offered as compliment to M.W.M. de Graauw. Our ways, objects, instruments and spectral domains parted after the 1970 eclipse but converge here.

  14. On the radial profile of gas-phase Fe/{\\alpha} ratio around distant galaxies

    CERN Document Server

    Zahedy, Fakhri S; Gauthier, Jean-René; Rauch, Michael

    2016-01-01

    This paper presents a study of the chemical compositions in cool gas around a sample of 27 intermediate-redshift galaxies. The sample comprises 13 massive quiescent galaxies at z=0.40-0.73 probed by QSO sightlines at projected distances d=3-400 kpc, and 14 star-forming galaxies at z=0.10-1.24 probed by QSO sightlines at d=8-163 kpc. The main goal of this study is to examine the radial profiles of the gas-phase Fe/{\\alpha} ratio in galaxy halos based on the observed Fe II to Mg II column density ratios. Because Mg+ and Fe+ share similar ionization potentials, the relative ionization correction is small in moderately ionized gas and the observed ionic abundance ratio N(Fe II)/N(Mg II) places a lower limit to the underlying (Fe/Mg) elemental abundance ratio. For quiescent galaxies, a median and dispersion of log =-0.06+/-0.15 is found at d ~100 kpc. On the other hand, star-forming galaxies exhibit log =-0.25+/-0.21 at d =-0.9+/-0.4 at larger distances. Including possible differential dust depletion or ionizati...

  15. Nonparametric 3D map of the IGM using the Lyman-alpha forest

    CERN Document Server

    Cisewski, Jessi; Freeman, Peter E; Genovese, Christopher R; Khandai, Nishikanta; Ozbek, Melih; Wasserman, Larry

    2014-01-01

    Visualizing the high-redshift Universe is difficult due to the dearth of available data; however, the Lyman-alpha forest provides a means to map the intergalactic medium at redshifts not accessible to large galaxy surveys. Large-scale structure surveys, such as the Baryon Oscillation Spectroscopic Survey (BOSS), have collected quasar (QSO) spectra that enable the reconstruction of HI density fluctuations. The data fall on a collection of lines defined by the lines-of-sight (LOS) of the QSO, and a major issue with producing a 3D reconstruction is determining how to model the regions between the LOS. We present a method that produces a 3D map of this relatively uncharted portion of the Universe by employing local polynomial smoothing, a nonparametric methodology. The performance of the method is analyzed on simulated data that mimics the varying number of LOS expected in real data, and then is applied to a sample region selected from BOSS. Evaluation of the reconstruction is assessed by considering various feat...

  16. ALMA observations of a z~3.1 Protocluster: Star Formation from Active Galactic Nuclei and Lyman-Alpha Blobs in an Overdense Environment

    CERN Document Server

    Alexander, D M; Harrison, C M; Mullaney, J R; Smail, I; Geach, J E; Hickox, R C; Hine, N K; Karim, A; Kubo, M; Lehmer, B D; Matsuda, Y; Rosario, D J; Stanley, F; Swinbank, A M; Umehata, H; Yamada, T

    2016-01-01

    We exploit ALMA 870um observations to measure the star-formation rates (SFRs) of eight X-ray detected Active Galactic Nuclei (AGNs) in a z~3.1 protocluster, four of which reside in extended Ly-alpha haloes (often termed Ly-alpha blobs: LABs). Three of the AGNs are detected by ALMA and have implied SFRs of ~220-410~M_sun/yr; the non detection of the other five AGNs places SFR upper limits of 100 kpc) do not host more luminous star formation than the smaller LABs, despite being an order of magnitude brighter in Ly-alpha emission. We use these results to discuss star formation as the power source of LABs.

  17. Application of LY-9801 primer hydrogenation catalyst for cracking gasoline%LY-9801裂解汽油一段加氢催化剂的应用

    Institute of Scientific and Technical Information of China (English)

    陈育辉

    2002-01-01

    介绍了LY-9801裂解汽油一段加氢催化剂在茂名石化乙烯工业公司加氢装置的应用情况.经过6 520 h试运行表明,LY-9801一段加氢催化剂各项分析指标合格,完全满足C5~C8 组分工况的使用要求.

  18. Localized corrosion of LY12CZ under stress in chloride media

    Institute of Scientific and Technical Information of China (English)

    RAO Si-xian; ZHANG Zheng; ZHU Li-qun; ZHONG Qun-peng

    2006-01-01

    Electrochemical methods were applied to investigate the corrosion behaviour of LY12CZ under applied stress in 3% sodium chloride aqueous solution. The experimental results indicate that LY12CZ shows two breakdown potentials on its polarization curve: one is related to the dissolution of the intermetallic particles and the other is related to the cracking of oxidation film and the dissolution of the matrix. When the stress is applied, it varies both breakdown potentials and makes the intermetallic particles and matrix dissolute at lower potentials. The relationship between the variation of the two breakdown potentials and applied stress was summarized. At the same time the influence of stress on the pitting and intergranular corrosion sensitivity of LY12CZ was also investigated. From the results it can be concluded that the stress can significantly affect the localized corrosion behaviour of LY12CZ in 3% NaCl solution.

  19. VEGF Production by Ly6C+high Monocytes Contributes to Ventilator-Induced Lung Injury

    National Research Council Canada - National Science Library

    Shi, Chung-Sheng; Huang, Tzu-Hsiung; Lin, Chin-Kuo; Li, Jhy-Ming; Chen, Mei-Hsin; Tsai, Mei-Ling; Chang, Chih-Ching

    2016-01-01

      Background Mechanical ventilation is a life-saving procedure for patients with acute respiratory failure, although it may cause pulmonary vascular inflammation and leakage, leading to ventilator-induced lung injury (VILI). Ly6C...

  20. ELECTROCHEMICAL FEATURES DURING PITTING CORROSION OF LY12 ALUMINUM ALLOY IN DIFFERENT NEUTRAL SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    F.H. Cao; Z. Zhang; Y.L. Cheng; J.F. Li; J.Q. Zhang; C.N. Cao

    2003-01-01

    The electrochemical features of commercial airframe material, Al alloy LY12, in 0. 349mol/L neutral sodium chloride (NaCl) and sodium sulfate (Na2SO4) solutions were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization techniques. The microstructure of the as-tested samples was studied by scanning electron microscopy. The results show that the Nyquist plots of LY12 at different immersion time displayed different fe atures, indicating that the Cl- ions elevate the corrosion rate and inhibit the repassivation of a metastable pit. It also shows that the corrosion product of LY12 formed in SO2-4 solution isn't easy to dissolve, and it will cover the surface of working electrode in the electrolyte. SEM images indicate that the corrosion apparent area and pit number of LY12 in NaCl solution are greater than that in Na2SO4 solution.

  1. GALVANIC CORROSION AND PROTECTION OF GECM/LY12CZ COUPLES UNDER DIFFERENT ATMOSPHERIC EXPOSURE CONDITIONS

    Institute of Scientific and Technical Information of China (English)

    F. Lu; Q.P. Zhong; C.X. Cao

    2003-01-01

    Galvanic compatibility between graphite epoxy composite materials (GECM) andLY12CZ aluminum alloy was evaluated in different atmospheric corrosion environ-ments and by laboratory electrochemical measurements. Open circuit potential elec-trochemical measurements showed a relatively large potential difference about 1 voltbetween the GECM and LY12CZ aluminum alloy, and this difference provided thedriving force for galvanic corrosion of the LY12CZ aluminum alloy as an anode.Having been exposed for 1, 3 or 5 years in Beijing, Tuandao and Wanning station,GECM/L Y12CZ couples showed significant losses of strength and elongation. Protec-tive coatings and non-conductive barriers breaking the galvanic corrosion circuit wereevaluated under the same atmospheric corrosive conditions. Epoxy primer paint, glasscloth barriers and LY12CZ anodizing were effective in galvanic corrosion control forGECM/L Y12CZ couples.

  2. Trahv? Herned klassinurgas? Või hoopis ihunuhtlus? / Pilme, Lea; Kivistik, Ly; Sirgmets, Raili; Part, Aivar

    Index Scriptorium Estoniae

    2008-01-01

    Suhtumisest koolijuhtidele trahvimisõiguse andmise ideesse vestlevad Rakvere Põhikooli direktor Lea Pilme, Uhtna Põhikooli direktor Ly Kivistik, Väike-Maarja Gümnaasiumi direktor Raili Sirgmets ja Rakvere Gümnaasiumi direktor Aivar Part

  3. The Properties of Lyα Nebulae: Gas Kinematics from Nonresonant Lines

    Science.gov (United States)

    Yang, Yujin; Zabludoff, Ann; Jahnke, Knud; Davé, Romeel

    2014-10-01

    With the Very Large Telescope/X-shooter, we obtain optical and near-infrared spectra of six Lyα blobs at z ~ 2.3. For a total sample of eight Lyα blobs (including two that we have previously studied), the majority (6/8) have broadened Lyα profiles with shapes ranging from a single peak to symmetric or asymmetric double-peaked. The remaining two systems, in which the Lyα profile is not significantly broader than the [O III] or Hα emission lines, have the most spatially compact Lyα emission, the smallest offset between the Lyα and the [O III] or Hα line velocities, and the only detected C IV and He II lines in the sample, implying that a hard ionizing source, possibly an active galactic nucleus (AGN), is responsible for their lower optical depth. Using three measures—the velocity offset between the Lyα line and the nonresonant [O III] or Hα line (Δv Lyα), the offset of stacked interstellar metal absorption lines, and a new indicator, the spectrally resolved [O III] line profile—we study the kinematics of gas along the line of sight to galaxies within each blob center. These three indicators generally agree in velocity and direction and are consistent with a simple picture in which the gas is stationary or slowly outflowing at a few hundred km s-1 from the embedded galaxies. The absence of stronger outflows is not a projection effect: the covering fraction for our sample is limited to metal absorption line offsets suggest no significant bulk motion, we use a simple radiative transfer model to make the first column density measurement of gas in an embedded galaxy, finding it consistent with a damped Lyα absorption system. Overall, the absence of clear inflow signatures suggests that the channeling of gravitational cooling radiation into Lyα is not significant over the radii probed here. However, one peculiar system (CDFS-LAB10) has a blueshifted Lyα component that is not obviously associated with any galaxy, suggesting either displaced gas arising

  4. Rapid decline of Lyα emission toward the reionization era

    Energy Technology Data Exchange (ETDEWEB)

    Tilvi, V.; Papovich, C. [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77845 (United States); Finkelstein, S. L.; Song, M. [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712 (United States); Long, J. [Department of Statistics, Texas A and M, College Station, TX 77845 (United States); Dickinson, M. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Ferguson, H. C.; Koekemoer, A. M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Giavalisco, M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Mobasher, B. [Department of Physics and Astronomy, University of California, Riverside, CA 92521 (United States)

    2014-10-10

    The observed deficit of strongly Lyα emitting galaxies at z > 6.5 is attributed to increasing neutral hydrogen in the intergalactic medium (IGM) and/or to the evolving galaxy properties. To investigate this we have performed very deep near-IR spectroscopy of z ≳ 7 galaxies using MOSFIRE on the Keck-I Telescope. We measure the Lyα fraction at z ∼ 8 using two methods. First, we derived N {sub Lyα}/N {sub tot} directly, using extensive simulations to correct for incompleteness. Second, we used a Bayesian formalism (introduced by Treu et al.) that compares the z > 7 galaxy spectra to models of the Lyα equivalent width (W {sub Lyα}) distribution at z ∼ 6. We explored two simple evolutionary scenarios: pure number evolution where Lyα is blocked in some fraction of galaxies (perhaps due to the IGM being opaque along only some fraction of sightlines) and uniform dimming evolution where Lyα is attenuated in all galaxies by a constant factor (perhaps owing to processes from galaxy evolution or a slowly increasing IGM opacity). The Bayesian formalism places stronger constraints compared with the direct method. Combining our data with that in the literature, we find that at z ∼ 8 the Lyα fraction has dropped by a factor of >3 (84% confidence interval) using both the dimming and number evolution scenarios, compared to the z ∼ 6 values. Furthermore, we find a tentative positive Bayesian evidence favoring the number evolution scenario over dimming evolution, extending trends observed at z ≲ 7 to higher redshift. A comparison of our results with theoretical models implies the IGM volume averaged neutral hydrogen fraction ≳ 0.3, suggesting that we are likely witnessing reionization in progress at z ∼ 8.

  5. CCN1/CYR61-mediated meticulous patrolling by Ly6Clow monocytes fuels vascular inflammation.

    Science.gov (United States)

    Imhof, Beat A; Jemelin, Stephane; Ballet, Romain; Vesin, Christian; Schapira, Marco; Karaca, Melis; Emre, Yalin

    2016-08-16

    Inflammation is characterized by the recruitment of leukocytes from the bloodstream. The rapid arrival of neutrophils is followed by a wave of inflammatory lymphocyte antigen 6 complex (Ly6C)-positive monocytes. In contrast Ly6C(low) monocytes survey the endothelium in the steady state, but their role in inflammation is still unclear. Here, using confocal intravital microscopy, we show that upon Toll-like receptor 7/8 (TLR7/8)-mediated inflammation of mesenteric veins, platelet activation drives the rapid mobilization of Ly6C(low) monocytes to the luminal side of the endothelium. After repeatedly interacting with platelets, Ly6C(low) monocytes commit to a meticulous patrolling of the endothelial wall and orchestrate the subsequent arrival and extravasation of neutrophils through the production of proinflammatory cytokines and chemokines. At a molecular level, we show that cysteine-rich protein 61 (CYR61)/CYR61 connective tissue growth factor nephroblastoma overexpressed 1 (CCN1) protein is released by activated platelets and enables the recruitment of Ly6C(low) monocytes upon vascular inflammation. In addition endothelium-bound CCN1 sustains the adequate patrolling of Ly6C(low) monocytes both in the steady state and under inflammatory conditions. Blocking CCN1 or platelets with specific antibodies impaired the early arrival of Ly6C(low) monocytes and abolished the recruitment of neutrophils. These results refine the leukocyte recruitment cascade model by introducing endothelium-bound CCN1 as an inflammation mediator and by demonstrating a role for platelets and patrolling Ly6C(low) monocytes in acute vascular inflammation.

  6. Cold Accretion in Early Galaxy Formation and Its Lyα Signatures

    Science.gov (United States)

    Yajima, Hidenobu; Li, Yuexing; Zhu, Qirong; Abel, Tom

    2015-03-01

    Lyα emission has played an important role in detecting high-redshift galaxies, including recently distant ones at redshifts z\\gt 7. It may also contain important information concerning the origin of these galaxies. Here, we investigate the formation of a typical L* galaxy and its observational signatures at the earliest stage by combining a cosmological hydrodynamic simulation with three-dimensional radiative transfer (RT) calculations using the newly improved AR{{T}2} code. Our cosmological simulation uses the Aquila initial condition, which zooms in on a Milky-Way-like halo with high resolutions, and our RT couples multi-wavelength continuum, Lyα line, and ionization of hydrogen. We find that the modeled galaxy starts to form at redshift z ∼ 24 through the efficient accretion of cold gas, which produces a strong Lyα line with a luminosity of {{L}Lyα }∼ {{10}42} erg {{s}-1} as early as z ∼ 14. The Lyα emission appears to trace the cold, dense gas. The lines exhibit asymmetric, single-peak profiles, and are shifted to the blue wing, a characteristic feature of gas inflow. Moreover, the contribution to the total Lyα luminosity from excitation cooling increases with redshift and becomes dominant at z ≳ 6. We predict that L* galaxies such as the modeled one may be detected at z ≲ 8 by the James Webb Space Telescope and Atacama Large Millimeter Array with a reasonable integration time. Beyond redshift 12, however, the Lyα line may only be observable by spectroscopic surveys. Our results suggest that the Lyα line is one of the most powerful tools to detect the first generation of galaxies and decipher their formation mechanism.

  7. Disposition and metabolism of LY2452473, a selective androgen receptor modulator, in humans.

    Science.gov (United States)

    Yi, Ping; Rehmel, Jessica Fayer; Cassidy, Kenneth; Hadden, Chad; Campanale, Kristina; Patel, Nita; Johnson, Jason

    2012-12-01

    The disposition and metabolism of isopropyl N-[(2S)-7-cyano-4-(2-pyridylmethyl)-2,3-dihydro-1H-cyclopenta[b]indol-2-yl]carbamate (LY2452473; a selective androgen receptor modulator) in humans was characterized after a single 15-mg (100 μCi) oral dose of [¹⁴C]LY2452473 to six healthy male subjects. LY2452473 was absorbed rapidly (time to reach maximum plasma concentration for both LY2452473 and total radioactivity was 2-3 h) and cleared slowly (plasma terminal t(½) of 27 h for LY2452473 and 51 h for the total radioactivity). LY2452473 and metabolites S5 (acetylamine) and S12 (hydroxylation on the cyclopentene) were major circulating entities in plasma, accounting for approximately 42, 21, and 35% of the total radioactivity exposure, respectively, as calculated from relative area under the concentration versus time curves from zero to 48 h derived from the plasma radiochromatograms. The radioactive dose was almost completely recovered after 312 h with 47.9% of the dose eliminated in urine and 46.6% in feces. Minimal LY2452473 was detected in excreta, indicating that metabolic clearance was the main route of elimination. Multiple metabolic pathways were observed with no single metabolic pathway accounting for more than 30% of the dose in excreta. Metabolite S10 (a diol across the cyclopenta-indole linkage) was the largest excretory metabolite (approximately 14% of the dose). S10 displayed interesting chemical and chromatographic properties, undergoing conversion to the corresponding epoxide under acidic conditions and conversion back to the diol under neutral conditions. An in vitro phenotyping approach indicated that CYP3A4 was the largest contributor to LY2452473 depletion.

  8. THE GALAXY ENVIRONMENT OF A QSO AT z {approx} 5.7

    Energy Technology Data Exchange (ETDEWEB)

    Banados, Eduardo; Venemans, Bram; Walter, Fabian [Max Planck Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Kurk, Jaron [Max Planck Institut fuer Extraterrestrische Physik, Giessenbachstrasse, D-68165 Garching (Germany); Overzier, Roderik [Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1400, Austin, TX 78712-1205 (United States); Ouchi, Masami, E-mail: banados@mpia.de [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)

    2013-08-20

    High-redshift quasars are believed to reside in massive halos in the early universe and should therefore be located in fields with overdensities of galaxies, which are thought to evolve into galaxy clusters seen in the local universe. However, despite many efforts, the relationship between galaxy overdensities and z {approx} 6 quasars is ambiguous. This can possibly be attributed to the difficulty of finding galaxies with accurate redshifts in the vicinity of z {approx} 6 quasars. So far, overdensity searches around z {approx} 6 quasars have been based on studies of Lyman break galaxies (LBGs), which probe a redshift range of {Delta}z Almost-Equal-To 1. This range is large enough to select galaxies that may not be physically related to the quasar. We use deep narrow- and broadband imaging to study the environment of the z = 5.72 quasar ULAS J0203+0012. The redshift range probed by our narrow-band selection of Lyman alpha emitters (LAEs) is {Delta}z Almost-Equal-To 0.1, which is significantly narrower than the LBG searches. This is the first time that LAEs were searched for near a z {approx} 6 quasar, in an effort to provide clues about the environments of quasars at the end of the epoch of reionization. We find no enhancement of LAEs in the surroundings of ULAS J0203+0012 in comparison with blank fields. We explore different explanations and interpretations for this non-detection of a galaxy overdensity, including that (1) the strong ionization from the quasar may prevent galaxy formation in its immediate vicinity and (2) high-redshift quasars may not reside in the center of the most massive dark matter halos.

  9. Signatures of transition region explosive events in hydrogen Ly-beta profiles

    CERN Document Server

    Zhang, M; Tian, H; Chen, Y

    2010-01-01

    We search for signatures of transition region explosive events (EEs) in hydrogen Ly-beta profiles. Two rasters made by the SUMER (Solar Ultraviolet Measurements of Emitted Radiation) instrument on board SOHO in a quiet-Sun region and an equatorial coronal hole are selected for our study. Transition region explosive events are identified from profiles of C II 1037 Angstrom and O VI 1032 Angstrom, respectively. We compare Ly-beta profiles during EEs with those averaged in the entire quiet-Sun and coronal-hole regions. The relationship between the peak emission of Ly-beta profiles and the wing emission of C II and O VI during EEs is investigated. We find that the central part of Ly-beta profiles becomes more reversed and the distance of the two peaks becomes larger during EEs, both in the coronal hole and in the quiet Sun. The average Ly-beta profile of the EEs detected by C II has an obvious stronger blue peak. During EEs, there is a clear correlation between the increased peak emission of Ly-beta profiles and ...

  10. A Halo Model Approach to the 21 cm and Lyα Cross-correlation

    Science.gov (United States)

    Feng, Chang; Cooray, Asantha; Keating, Brian

    2017-09-01

    We present a halo-model-based approach to calculate the cross-correlation between 21 {cm} H i intensity fluctuations and {Ly}α emitters (LAE) during the epoch of reionization (EoR). Ionizing radiation around dark matter halos are modeled as bubbles with the size and growth determined based on the reionization photon production, among other physical parameters. The cross-correlation shows a clear negative-to-positive transition, associated with transition from ionized to neutral hydrogen in the intergalactic medium during EoR. The cross-correlation is subject to several foreground contaminants, including foreground radio point sources important for 21 {cm} experiments and low-z interloper emission lines, such as {{H}}α , O iii, and O ii, for {Ly}α experiments. Our calculations show that by masking out high fluxes in the {Ly}α measurement, the correlated foreground contamination on the 21 {cm}–{Ly}α cross-correlation can be dramatically reduced. We forecast the detectability of 21 {cm}–{Ly}α cross-correlation at different redshifts and adopt a Fisher matrix approach to estimate uncertainties on the key EoR parameters that have not been well constrained by other observations of reionization. This halo-model-based approach enables us to explore the EoR parameter space rapidly for different 21 {cm} and {Ly}α experiments.

  11. 裂解汽油二段加氢LY-9702和LY-9802复合床催化剂的工业应用%Industrial application of double bed used catalysts LY-9702 and LY-9802 in the second-stage of pyrolysis gasoline hydrogenation unit

    Institute of Scientific and Technical Information of China (English)

    蒋帮勇; 梁顺琴; 钱颖; 吴杰; 孙利民

    2008-01-01

    在广州石化汽油加氢装置中进行了二段加氢国产催化剂LY-9702和LY-9802的工业应用.结果表明,催化剂LY-9702和LY-9802具有低温加氢脱硫活性高、加氢稳定性能优良等特点.连续运行32个月后,反应器入口温度从使用初期的232℃缓慢上升至265℃;加氢汽油的溴价较低,最高不超过0.70 mg/g,含硫质量分数则小于0.5×10-6.与同类进口催化剂LD-145和HR-406相比较,使用催化剂LY-9702和LY-9802时,反应器入口温度低、加氢汽油的溴价低、运行周期约可延长2年,其综合性能尤其是加氢稳定性能超过进口催化剂.

  12. Large Area Lyman Alpha Survey: Finding Young Galaxies at z=4.5

    Science.gov (United States)

    Malhotra, S.; Rhoads, J.; Dey, A.; Stern, D.; Spinrad, H.

    Strong Lyα emission is a signpost of young stars and the absence of dust and thus indicates young galaxies. To find such a population of young galaxies at z=4.5 we started the Large Area Lyman Alpha survey (LALA). This survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on a large format (36' × 36') camera on the 4 meter telescope at KPNO. The volume density and star-formation contribution of the Lyα emitters at z=4.5 is comparable to that of Lyman break galaxies. With many candidates and a few spectroscopic confirmations in hand we discuss what the properties of Lyα emitters imply for galaxy and star formation in the early universe.

  13. Deep SAURON Spectral-Imaging of the diffuse Lyman-alpha halo LAB1 in SSA22

    CERN Document Server

    Bower, R; Bacon, R; Wilman, R J; Sullivan, M; Chapman, S C; Davies, R L; De Zeeuw, P T; Emsellem, E; Bower, Richard

    2004-01-01

    We have used the SAURON panoramic integral field spectrograph to study the structure of the Ly-alpha emission-line halo, LAB1, surrounding the sub-millimeter galaxy SMM J221726+0013. This emission-line halo was discovered during a narrow-band imaging survey of the z=3.1 large-scale structure in the SSA22 region. Our observations trace the emission halo out to almost 100 kpc from the sub-millimeter source and identify two distinct Ly-alpha `mini-haloes' around the nearby Lyman-break galaxies. The main emission region has a broad line profile, with variations in the line profile seeming chaotic and lacking evidence for a coherent velocity structure. The data also suggests that Ly-alpha emission is suppressed around the sub-mm source. Interpretation of the line structure needs care because Ly-alpha may be resonantly scattered, leading to complex radiative transfer effects, and we suggest that the suppression in this region arises because of such effects. We compare the structure of the central emission-line halo...

  14. The Lyman Alpha Reference Sample: V. The impact of neutral ISM kinematics and geometry on Lyman Alpha escape

    CERN Document Server

    Rivera-Thorsen, Thøger E; Östlin, Göran; Duval, Florent; Orlitová, Ivana; Verhamme, Anne; Mas-Hesse, J Miguel; Schaerer, Daniel; Cannon, John M; Otí-Floranes, Héctor; Sandberg, Andreas; Guaita, Lucia; Adamo, Angela; Atek, Hakim; Herentz, E Christian; Kunth, Daniel; Laursen, Peter; Melinder, Jens

    2015-01-01

    We present high-resolution far-UV spectroscopy of the 14 galaxies of the Lyman Alpha Reference Sample; a sample of strongly star-forming galaxies at low redshifts ($0.028 < z < 0.18$). We compare the derived properties to global properties derived from multi band imaging and 21 cm HI interferometry and single dish observations, as well as archival optical SDSS spectra. Besides the Lyman $\\alpha$ line, the spectra contain a number of metal absorption features allowing us to probe the kinematics of the neutral ISM and evaluate the optical depth and and covering fraction of the neutral medium as a function of line-of-sight velocity. Furthermore, we show how this, in combination with precise determination of systemic velocity and good Ly$\\alpha$ spectra, can be used to distinguish a model in which separate clumps together fully cover the background source, from the "picket fence" model named by Heckman et al. (2011). We find that no one single effect dominates in governing Ly$\\alpha$ radiative transfer and ...

  15. Lyman-alpha Forests cool Warm Dark Matter

    CERN Document Server

    Baur, Julien; Yèche, Christophe; Magneville, Christophe; Viel, Matteo

    2015-01-01

    The free-streaming of keV-scale particles impacts structure growth on scales that are probed by the Lyman-alpha forest of distant quasars. Using an unprecedentedly large sample of medium-resolution QSO spectra from the ninth data release of SDSS, along with a state-of-the-art set of hydrodynamical simulations to model the Lyman-alpha forest in the non-linear regime, we issue the tightest bounds to date on pure dark matter particles: $m_X \\gtrsim 4.35 \\: \\rm{keV}$ (95% CL) for early decoupled thermal relics such as a hypothetical gravitino, and its corresponding bound for a non-resonantly produced right-handed neutrino $m_s \\gtrsim 31.7 \\: \\rm{keV}$ (95% CL). Thanks to SDSS-III data featuring smaller uncertainties and covering a larger redshift range than SDSS-I data, our bounds improve upon those established by previous works and are further at odds with a purely non-resonantly produced sterile neutrino as dark matter.

  16. THE Lyα LINE PROFILES OF ULTRALUMINOUS INFRARED GALAXIES: FAST WINDS AND LYMAN CONTINUUM LEAKAGE

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Crystal L.; Wong, Joseph [Department of Physics, University of California, Santa Barbara, CA, 93106 (United States); Dijkstra, Mark [Institute of Theoretical Astrophysics, University of Oslo, Postboks 1029, 0858 Oslo (Norway); Henry, Alaina [Astrophysics Science Division, Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States); Soto, Kurt T. [Institute for Astronomy, Department of Physics, ETH Zurich, CH-8093 Zurich (Switzerland); Danforth, Charles W., E-mail: cmartin@physics.ucsb.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO, 80309 (United States)

    2015-04-10

    We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect Lyα emission from eight ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the Lyα profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding −1000 km s{sup −1} in three H ii-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the Lyα line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The Lyα attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the Lyα photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the Lyα and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the Lyα emission increases nonlinearly with the ULIRG bolometric luminosity and represents about 0.1–1% of the radiative cooling from the hot winds in the H ii-dominated ULIRGs.

  17. The Lyα Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage

    Science.gov (United States)

    Martin, Crystal L.; Dijkstra, Mark; Henry, Alaina; Soto, Kurt T.; Danforth, Charles W.; Wong, Joseph

    2015-04-01

    We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect Lyα emission from eight ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the Lyα profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding -1000 km s-1 in three H ii-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the Lyα line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The Lyα attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the Lyα photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the Lyα and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the Lyα emission increases nonlinearly with the ULIRG bolometric luminosity and represents about 0.1-1% of the radiative cooling from the hot winds in the H ii-dominated ULIRGs.

  18. Specific depletion of Ly6C(hi inflammatory monocytes prevents immunopathology in experimental cerebral malaria.

    Directory of Open Access Journals (Sweden)

    Beatrix Schumak

    Full Text Available Plasmodium berghei ANKA (PbA infection of C57BL/6 mice leads to experimental cerebral malaria (ECM that is commonly associated with serious T cell mediated damage. In other parasitic infection models, inflammatory monocytes have been shown to regulate Th1 responses but their role in ECM remains poorly defined, whereas neutrophils are reported to contribute to ECM immune pathology. Making use of the recent development of specific monoclonal antibodies (mAb, we depleted in vivo Ly6C(hi inflammatory monocytes (by anti-CCR2, Ly6G+ neutrophils (by anti-Ly6G or both cell types (by anti-Gr1 during infection with Ovalbumin-transgenic PbA parasites (PbTg. Notably, the application of anti-Gr1 or anti-CCR2 but not anti-Ly6G antibodies into PbTg-infected mice prevented ECM development. In addition, depletion of Ly6C(hi inflammatory monocytes but not neutrophils led to decreased IFNγ levels and IFNγ+CD8+ T effector cells in the brain. Importantly, anti-CCR2 mAb injection did not prevent the generation of PbTg-specific T cell responses in the periphery, whereas anti-Gr1 mAb injection strongly diminished T cell frequencies and CTL responses. In conclusion, the specific depletion of Ly6C(hi inflammatory monocytes attenuated brain inflammation and immune cell recruitment to the CNS, which prevented ECM following Plasmodium infection, pointing out a substantial role of Ly6C+ monocytes in ECM inflammatory processes.

  19. Modelling Lyman α forest cross-correlations with LyMAS

    Science.gov (United States)

    Lochhaas, Cassandra; Weinberg, David H.; Peirani, Sébastien; Dubois, Yohan; Colombi, Stéphane; Blaizot, Jérémy; Font-Ribera, Andreu; Pichon, Christophe; Devriendt, Julien

    2016-10-01

    We use the Lyα Mass Association Scheme (LyMAS) to predict cross-correlations at z = 2.5 between dark matter haloes and transmitted flux in the Lyα forest, and compare to cross-correlations measured for quasars and damped Lyα systems (DLAs) from the Baryon Oscillation Spectroscopic Survey (BOSS) by Font-Ribera et al. We calibrate LyMAS using Horizon-AGN hydrodynamical cosmological simulations of a (100 h- 1 Mpc)3 comoving volume. We apply this calibration to a (1 h- 1 Gpc)3 simulation realized with 20483 dark matter particles. In the 100 h- 1 Mpc box, LyMAS reproduces the halo-flux correlations computed from the full hydrodynamic gas distribution very well. In the 1 h- 1 Gpc box, the amplitude of the large-scale cross-correlation tracks the halo bias bh as expected. We provide empirical fitting functions that describe our numerical results. In the transverse separation bins used for the BOSS analyses, LyMAS cross-correlation predictions follow linear theory accurately down to small scales. Fitting the BOSS measurements requires inclusion of random velocity errors; we find best-fitting rms velocity errors of 399 and 252 {km} {s}^{-1} for quasars and DLAs, respectively. We infer bias-weighted mean halo masses of M_h/10^{12} h^{-1} M_{⊙}=2.19^{+0.16}_{-0.15} and 0.69^{+0.16}_{-0.14} for the host haloes of quasars and DLAs, with ˜0.2 dex systematic uncertainty associated with redshift evolution, intergalactic medium parameters, and selection of data fitting range.

  20. The Ly49E receptor inhibits the immune control of acute Trypanosoma cruzi infection

    Directory of Open Access Journals (Sweden)

    Jessica Filtjens

    2016-11-01

    Full Text Available The protozoan parasite Trypanosoma cruzi (T. cruzi circulates in the blood upon infection and invades a variety of cells. Parasites intensively multiply during the acute phase of infection and persist lifelong at low levels in tissues and blood during the chronic phase. Natural killer (NK and NKT cells play an important role in the immune control of T. cruzi infection, mainly by releasing the cytokine IFN-γ that activates the microbicidal action of macrophages and other cells and shapes a protective type 1 immune response. The mechanisms by which immune cells are regulated to produce IFN-γ during T. cruzi infection are still incompletely understood. Here, we show that urokinase plasminogen activator (uPA is induced early upon T. cruzi infection, and remains elevated until day 20 post inoculation. We previously demonstrated that the inhibitory receptor Ly49E, which is expressed, among others, on NK and NKT cells, is triggered by uPA. Therefore, we compared wild type (WT to Ly49E knockout (KO mice for their control of experimental T. cruzi infection. Our results show that young, i.e. 4- and 6-week-old, Ly49E KO mice control the infection better than WT mice, indicated by a lower parasite load and less cachexia. The beneficial effect of Ly49E depletion is more obvious in 4-week-old male than in female mice and weakens in 8-week-old mice. In young mice, the lower T. cruzi parasitemia in Ly49E KO mice is paralleled by higher IFN-γ production compared to their WT controls. Our data indicate that Ly49E receptor expression inhibits the immune control of T. cruzi infection. This is the first demonstration that the inhibitory Ly49E receptor can interfere with the immune response to a pathogen in vivo.

  1. High redshift galaxies and the Lyman-alpha forest in a CDM universe

    CERN Document Server

    Croft, R A C; Springel, V; Westover, M; White, M; Croft, Rupert A.C.; Hernquist, Lars; Springel, Volker; Westover, Michael; White, Martin

    2002-01-01

    We use a cosmological hydrodynamic simulation of a cold dark matter universe to investigate theoretically the relationship between high redshift galaxies and the Lyman=alpha forest at redshift z=3. Galaxies in the simulation are surrounded by halos of hot gas, which nevertheless contain enough neutral hydrogen to cause a Ly-alpha flux decrement, its strength increasing with galaxy mass. A comparison with recent observational data by Adelberger et. al on the Ly-alpha forest around galaxies reveals that actual galaxies may have systematically less Ly-alpha absorption within 1 Mpc of them than our simulated galaxies. In order to investigate this possibility, we add several simple prescriptions for galaxy feedback on the IGM to the evolved simulation. These include the effect of photoionizing background radiation coming from galactic sources, galactic winds whose only effect is to deposit thermal energy into the IGM, and another, kinetic model for winds, which are assumed to evacuate cavities in the IGM around ga...

  2. Neutral atomic-carbon QSO absorption-line systems at z>1.5: Sample selection, HI content, reddening, and 2175 A extinction feature

    CERN Document Server

    Ledoux, C; Petitjean, P; Srianand, R

    2015-01-01

    We present the results of a search for cold gas at high redshift along QSO lines-of-sight carried out without any a priori assumption on the neutral atomic-hydrogen (HI) content of the absorbers. To do this, we systematically looked for neutral-carbon (CI) 1560,1656 transition lines in low-resolution QSO spectra from the SDSS database. We built up a sample of 66 CI absorbers with redshifts 1.521 compared to systematic DLA surveys. We study empirical relations between W_r(CI), N(HI), E(B-V) and the strength of the 2175 A extinction feature, the latter being detected in about 30% of the CI absorbers. We show that the 2175 A feature is weak compared to Galactic lines-of-sight exhibiting the same amount of reddening. This is probably the consequence of current or past star formation in the vicinity of the CI systems. We also find that the strongest CI systems tend to have the largest amounts of dust and that the metallicity of the gas and its molecular fraction is likely to be high in a large number of cases.

  3. Variability of GeV gamma-ray emission in QSO B0218+357 due to microlensing on intermediate size structures

    Science.gov (United States)

    Sitarek, J.; Bednarek, W.

    2016-06-01

    Strong gravitational lensing leads to an occurrence of multiple images, with different magnifications, of a lensed source. Those magnifications can in turn be modified by microlensing on smaller mass scales within the lens. Recently, measurements of the changes in the magnification ratio of the individual images have been proposed as a powerful tool for estimation of the size and velocity of the emission region in the lensed source. The changes of the magnification ratios in blazars PKS1830-211 and QSO B0218+357, if interpreted as caused by a microlensing on individual stars, put strong constraints on those two variables. These constraints are difficult to accommodate with the current models of gamma-ray emission in blazars. In this paper we study if similar changes in the magnification ratio can be caused by microlensing on intermediate size structures in the lensing galaxy. We investigate in details three classes of possible lenses: globular clusters (GCs), open clusters (OCs) and giant molecular clouds (GMCs). We apply this scenario to the case of QSO B0218+357. Our numerical simulations show that changes in magnifications with similar time-scales can be obtained for relativistically moving emission regions with sizes up to 0.01 pc in the case of microlensing on the cores of GCs or clumps in GMCs. From the density of such structures in spiral galaxies we estimate however that lensing in GMCs would be more common.

  4. Multi-wavelength Observations of the Gas-rich Host Galaxy of PDS 456: a New Challenge for the ULIRG-to-QSO Transition Scenario

    CERN Document Server

    Yun, M S; Frayer, D T; Tilanus, R P J; Yun, Min S.

    2004-01-01

    We report new K-band, radio continuum, and CO (1-0) imaging observations and 850 micron photometric observations of PDS 456, the most luminous QSO in the local universe (z<0.3). The 0.6'' resolution K-band image obtained using the Keck telescope shows three compact K~16.5 (M(K)~ -21) sources at a projected distance of ~10 kpc to the southwest, and the host galaxy of PDS 456 may be interacting or merging with one or more companions. The observations using the OVRO millimeter array has revealed a narrow CO (1-0) line (FWHM = 181 km/s) centered at z=0.1849, and 9 x 10^9 solar mass of molecular gas mass is inferred. Radio continuum luminosity is nearly an order of magnitude larger than expected from its FIR luminosity, and the radio source, unresolved by the 2" beam of the VLA, is dominated by the AGN activity. Our 850 micron photometric observations suggest that the cold dust content of the host galaxy is less than one half of the amount in Arp 220. Its SED has both a QSO-like and a ULIRG-like nature, and the...

  5. The MUSE view of QSO PG1307+085: An elliptical galaxy on the $M_{BH}-\\sigma_*$ relation interacting with its group environment

    CERN Document Server

    Husemann, B; Scharwächter, J; Woo, J -H; Choudhury, O S

    2015-01-01

    We report deep optical integral-field spectroscopy with the MUSE of the luminous radio-quiet QSO PG1307+085 (z=0.154) obtained during the commissioning of the instrument. Given the high sensitivity and spatial resolution delivered by MUSE, we are able to resolve the compact ($r_e$~1.3") elliptical host galaxy. After careful spectroscopic deblending of the QSO and host galaxy emission, we infer a stellar velocity dispersion of $155\\pm19$km/s. This places PG1307+085 local $M_{BH}-\\sigma_*$ relation within the intrinsic scatter but offset towards a higher black hole mass with respect to the mean relation. The observations with MUSE also reveal a large extended ENLR around PG1307+085 reaching out to 30kpc. In addition, we detect a faint bridge of ionized gas towards the most massive galaxy of the galaxy group being just 20" (50kpc) away. Previous long-slit spectroscopic observations missed most of these extended features due to a miss-aligned slit. The ionized gas kinematics does not show any evidence for gas out...

  6. Deep-Imaging Observations of a Candidate of an Absorbed QSO at z=0.653, AX J131831+3341

    CERN Document Server

    Akiyama, M; Tamura, N; Doi, M; Kimura, M; Komiyama, Yu; Miyazaki, S; Nakata, F; Okamura, S; Sekiguchi, M; Shimasaku, K; Yagi, M; Hamabe, M; Yoshida, M; Takata, T

    2000-01-01

    The results of deep-imaging observations of a candidate of an absorbed QSO at z=0.653, AX J131831+3341, are presented. AX J131831+3341 was found during the course of optical follow-up observations of the ASCA Large Sky Survey, and has an X-ray luminosity of 10^{45} erg s^{-1} (2-10keV), which corresponds to those of QSOs. Its optical spectrum shows no significant broad H_beta emission line, suggesting that the object is an absorbed QSO. Deep R and V band images reveal the presence of a point-like nucleus and an asymmetric extended component. The nuclear component has a blue color, and the optical magnitude is much fainter than that expected from the observed X-ray flux for typical type-1 AGNs. These photometric properties and the presence of broad MgII 2800A emission can be explained simultaneously if the observed nuclear light is dominated by scattered nuclear light, though there is a possibility that the nuclear component is a slightly absorbed nucleus if its intrinsic X-ray to optical flux ratio is the lar...

  7. Molecular Mechanism of Enhanced Anticancer Effect of Nanoparticle Formulated LY2835219 via p16-CDK4/6-pRb Pathway in Colorectal Carcinoma Cell Line

    Directory of Open Access Journals (Sweden)

    Xu Tang

    2016-01-01

    Full Text Available LY2835219 is a dual inhibitor to CDK4 and CDK6. This study was to prepare LY2835219-loaded chitosan nanoparticles (CNP/LY and LY2835219-loaded hyaluronic acid-conjugated chitosan nanoparticles (HACNP/LY and revealed their anticancer effect and influence on p16-CDK4/6-pRb pathway against colon cell line. The nanoparticle sizes of CNP/LY and HACNP/LY were approximately 195±39.6 nm and 217±31.1 nm, respectively. The zeta potentials of CNP/LY and HACNP/LY were 37.3±1.5 mV and 30.3±2.2 mV, respectively. And the preparation process showed considerable drug encapsulation efficiency and loading efficiency. LY2835219, CNP/LY, and HACNP/LY inhibited HT29 cell proliferation with 0.68, 0.54, and 0.30 μM of IC50, respectively. G1 phase was arrested by LY2835219 and its formulations. Furthermore, inhibition of CDK4/6 by LY2835219 formulations induced CDK4, CDK6, cyclin D1, and pRb decrease and p16 increase at both protein and mRNA levels. Overall, nanoparticle formulated LY2835219 could enhance the cytotoxicity and cell cycle arrest, and HACNP/LY strengthened the trend furtherly compared to CNP/LY. It is the first time to demonstrate the anticancer effect and mechanism against HT29 by LY2835219 and its nanoparticles. The drug and its nanoparticle formulations delay the cell growth and arrest cell cycle through p16-CDK4/6-pRb pathway, while the nanoparticle formulated LY2835219 could strengthen the process.

  8. A gain of novel tissue specificity in the human Ly-6 gene E48.

    Science.gov (United States)

    Brakenhoff, R H; van Dijk, M; Rood-Knippels, E M; Snow, G B

    1997-11-15

    The Ly-6 Ag family consists of glycosyl-phosphatidylinositol-anchored surface proteins with a molecular mass of about 15 kDa. Seven members of the murine family have been characterized, and from five of these the genes have been cloned. Three members of the human family have been characterized: CD59, Ag E48, and the RIG-E or TSA-1/Sca-2 Ag. Most of the genes are expressed on lymphocytes, but some are expressed on other tissues as well. The mapped genes of the murine Ly-6 Ags, as well as of CD59, were shown to have a highly conserved structure, each consisting of four exons. The human E48 Ag was originally identified as a target Ag for radioimmunotherapy of patients with squamous cell carcinoma. The Ag is expressed on keratinocytes, but evidently not on lymphocytes. Molecular cloning of the cDNA encoding the Ag revealed that this Ag is most likely the human homologue of the murine Ly-6 Ag, ThB. In this paper, we describe that, in contrast to all other Ly-6 genes, the gene encoding the human E48 Ag consists of only three exons. Sequences at the 5' end of the transcription start site were shown to drive keratinocyte-associated expression. These data suggest that the functional elimination of an ancestral Ly-6 exon 1 switched the expression from lymphocytes toward keratinocytes.

  9. [Development and validation of event-specific quantitative PCR method for genetically modified maize LY038].

    Science.gov (United States)

    Mano, Junichi; Masubuchi, Tomoko; Hatano, Shuko; Futo, Satoshi; Koiwa, Tomohiro; Minegishi, Yasutaka; Noguchi, Akio; Kondo, Kazunari; Akiyama, Hiroshi; Teshima, Reiko; Kurashima, Takeyo; Takabatake, Reona; Kitta, Kazumi

    2013-01-01

    In this article, we report a novel real-time PCR-based analytical method for quantitation of the GM maize event LY038. We designed LY038-specific and maize endogenous reference DNA-specific PCR amplifications. After confirming the specificity and linearity of the LY038-specific PCR amplification, we determined the conversion factor required to calculate the weight-based content of GM organism (GMO) in a multilaboratory evaluation. Finally, in order to validate the developed method, an interlaboratory collaborative trial according to the internationally harmonized guidelines was performed with blind DNA samples containing LY038 at the mixing levels of 0, 0.5, 1.0, 5.0 and 10.0%. The precision of the method was evaluated as the RSD of reproducibility (RSDR), and the values obtained were all less than 25%. The limit of quantitation of the method was judged to be 0.5% based on the definition of ISO 24276 guideline. The results from the collaborative trial suggested that the developed quantitative method would be suitable for practical testing of LY038 maize.

  10. Phosphatidylinositol 3-kinase inhibitor, LY294002, induced senescence-like changes in human diploid fibroblasts

    Institute of Scientific and Technical Information of China (English)

    李淑萍; 张宗玉; 童坦君

    2003-01-01

    Objective To reveal the role of Phosphatidylinositol 3-kinases (PI3Ks) in regulating human diploid fibroblast (2BS cell) senescence as well as the possible mechanisms involved.Methods Using a PI3Ks specific inhibitor, LY294002, cell cycle, apoptosis, proliferation, senescence association β-galactosidase staining as well as senescence association CKIs, p16 INK4 and p21 Cip1 protein expressions were all measured in the low passages of 2BS cells.Results Both 25 μmol/L and 50 μmol/L concentrations of LY294002 could cause a significant decrease in cells entering into S phase, and this cell cycle of G 1 phase arrest was dose-dependent. Meanwhile, LY294002 contributed to apoptosis, caused 2BS cell growth arrest, and activated senescence association β-galactosidase (P<0.05). In addition, LY294002 could induce time-course expressions of p16 INK4 and p21 Cip1 in 2BS cell lines.Conclusions PI3Ks inhibitor LY294002 could induce senescence-like changes in 2BS cell lines. Two enescence associated CKIs,p16 INK4 and p21 Cip1, might be involved in this senescence phenotype proceeding in 2BS cell lines.

  11. An Ultraluminous Lyα Emitter with a Blue Wing at z = 6.6

    Science.gov (United States)

    Hu, E. M.; Cowie, L. L.; Songaila, A.; Barger, A. J.; Rosenwasser, B.; Wold, I. G. B.

    2016-07-01

    We report the detection of the most luminous high-redshift Lyα emitting galaxy (LAE) yet seen, with {log}L({{Ly}}α )=43.9\\quad {erg} {{{s}}}-1. The galaxy—COSMOS Lyα1, or COLA1—was detected in a search for ultraluminous LAEs with Hyper Suprime-Cam on the Subaru telescope. It was confirmed as lying at z = 6.593, based on a Lyα line detection obtained from follow-up spectroscopy with the DEIMOS spectrograph on Keck II. COLA1 is the first very high-redshift LAE to show a multi-component Lyα line profile with a blue wing, which suggests that it could lie in a highly ionized region of the intergalactic medium (IGM) and could have significant infall. If this interpretation is correct, then ultraluminous LAEs like COLA1 offer a unique opportunity to determine the properties of the H ii regions around these galaxies, which will help in understanding the ionization of the z ˜ 7 IGM.

  12. The dust, nebular emission, and dependence on QSO radio properties of the associated Mg II absorption line systems

    Energy Technology Data Exchange (ETDEWEB)

    Khare, Pushpa [CSIR Emeritus Scientist, IUCAA, Ganeshkhind, Pune 411007 (India); Daniel, Vanden Berk [Physics Department, St. Vincent College, Latrobe, PA 15650 (United States); Rahmani, Hadi [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); York, Donald G., E-mail: pushpakhare@gmail.com [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2014-10-10

    We studied dust reddening and [O II] emission in 1730 Mg II associated absorption systems (AAS; relative velocity with respect to QSOs, ≤3000 km s{sup –1}; in units of velocity of light, β, ≤0.01) with 0.4 ≤z {sub abs} ≤ 2 in the Sloan Digital Sky Survey DR7, focusing on their dependence on the radio and other QSO properties. We used control samples, several with matching radio properties, to show that (1) AAS in radio-detected (RD) QSOs cause 2.6 ± 0.2 times higher dust extinction than those in radio-undetected (RUD) ones, which in turn cause 2.9 ± 0.7 times the dust extinction in the intervening systems; (2) AAS in core-dominated QSOs cause 2.0 ± 0.1 times higher dust extinction than those in lobe-dominated QSOs; (3) the occurrence of AAS is 2.1 ± 0.2 times more likely in RD QSOs than in RUD QSOs and 1.8 ± 0.1 time more likely in QSOs having black holes with masses larger than 1.23 × 10{sup 9} M {sub ☉} than in those with lower-mass black holes; and (4) there is excess flux in [O II]λ3727 emission in the composite spectra of the AAS samples compared with those of the control samples, which is at the emission redshift. The presence of AAS enhances the O II emission from the active galactic nucleus and/or the host galaxy. This excess is similar for both RD and RUD samples and is 2.5 ± 0.4 times higher in lobe-dominated samples than in core-dominated samples. The excess depends on the black hole mass and Eddington ratio. All these point to the intrinsic nature of the AAS except for the systems with z {sub abs} > z {sub em}, which could be infalling galaxies.

  13. Cosmochemistry, cosmology and fundamental constants: High-resolution spectroscopy of damped Lyman-alpha systems

    CERN Document Server

    Quast, R; Smette, A; Garcet, O; Ledoux, C; López, S; Wisotzki, L

    2004-01-01

    Spectroscopy of QSO absorption lines provides essential observational input for the study of nucleosynthesis and chemical evolution of galaxies at high redshift. But new observations may indicate that present chemical abundance data are biased due to deficient spectral resolution and unknown selection effects: Recent high-resolution spectra reveal the hitherto unperceived chemical nonuniformity of molecular hydrogen-bearing damped Lyman-alpha (DLA) systems, and the novel H/ESO DLA survey produces compelling evidence for faint QSOs being attenuated by dust. We present a revised analysis of the molecular hydrogen-bearing DLA complex toward HE 0515-4414 showing nonuniform differential depletion of chemical elements onto dust grains, and introduce to the H/ESO DLA survey and its implications. Conclusively, we aim at starting an unbiased chemical abundance database established on high-resolution spectroscopic observations. New data to probe the temperature-redshift relation predicted by standard cosmology and to t...

  14. Ly6E/K Signaling to TGFβ Promotes Breast Cancer Progression, Immune Escape, and Drug Resistance.

    Science.gov (United States)

    AlHossiny, Midrar; Luo, Linlin; Frazier, William R; Steiner, Noriko; Gusev, Yuriy; Kallakury, Bhaskar; Glasgow, Eric; Creswell, Karen; Madhavan, Subha; Kumar, Rakesh; Upadhyay, Geeta

    2016-06-01

    Stem cell antigen Sca-1 is implicated in murine cancer stem cell biology and breast cancer models, but the role of its human homologs Ly6K and Ly6E in breast cancer are not established. Here we report increased expression of Ly6K/E in human breast cancer specimens correlates with poor overall survival, with an additional specific role for Ly6E in poor therapeutic outcomes. Increased expression of Ly6K/E also correlated with increased expression of the immune checkpoint molecules PDL1 and CTLA4, increased tumor-infiltrating T regulatory cells, and decreased natural killer (NK) cell activation. Mechanistically, Ly6K/E was required for TGFβ signaling and proliferation in breast cancer cells, where they contributed to phosphorylation of Smad1/5 and Smad2/3. Furthermore, Ly6K/E promoted cytokine-induced PDL1 expression and activation and binding of NK cells to cancer cells. Finally, we found that Ly6K/E promoted drug resistance and facilitated immune escape in this setting. Overall, our results establish a pivotal role for a Ly6K/E signaling axis involving TGFβ in breast cancer pathophysiology and drug response, and highlight this signaling axis as a compelling realm for therapeutic invention. Cancer Res; 76(11); 3376-86. ©2016 AACR. ©2016 American Association for Cancer Research.

  15. The role of Ly49E receptor expression on murine intraepithelial lymphocytes in intestinal cancer development and progression.

    Science.gov (United States)

    Van Acker, Aline; Louagie, Els; Filtjens, Jessica; Taveirne, Sylvie; Van Ammel, Els; Kerre, Tessa; Elewaut, Dirk; Taghon, Tom; Vandekerckhove, Bart; Plum, Jean; Leclercq, Georges

    2016-11-01

    Ly49E is a member of the Ly49 family of NK receptors and is distinct from other members of this family on the basis of its structural properties, expression pattern and ligand recognition. Importantly, Ly49E receptor expression is high on small intestinal and colonic intraepithelial lymphocytes (IELs). Intestinal IELs are regulators of the mucosal immune system and contribute to front-line defense at the mucosal barrier, including anti-tumor immune response. Whereas most Ly49 receptors have MHC class-I ligands, we showed that Ly49E is instead triggered by urokinase plasminogen activator (uPA). uPA has been extensively implicated in tumor development, where increased uPA expression correlates with poor prognosis. As such, we investigated the role of Ly49E receptor expression on intestinal IELs in the anti-tumor immune response. For this purpose, we compared Ly49E wild-type mice to Ly49E knockout mice in two established tumor models: Apc(Min/+)-mediated and azoxymethane-induced intestinal cancer. Our results indicate that Ly49E expression on IELs does not influence the development or progression of intestinal cancer.

  16. Levels of the Rab GDP dissociation inhibitor (GDI) are altered in the prenatal restrain stress mouse model of schizophrenia and are differentially regulated by the mGlu2/3 receptor agonists, LY379268 and LY354740.

    Science.gov (United States)

    Orlando, Rosamaria; Borro, Marina; Motolese, Marta; Molinaro, Gemma; Scaccianoce, Sergio; Caruso, Alessandra; di Nuzzo, Luigi; Caraci, Filippo; Matrisciano, Francesco; Pittaluga, Anna; Mairesse, Jerome; Simmaco, Maurizio; Nisticò, Robert; Monn, James A; Nicoletti, Ferdinando

    2014-11-01

    LY379268 and LY354740, two agonists of mGlu2/3 metabotropic glutamate receptors, display different potencies in mouse models of schizophrenia. This differential effect of the two drugs remains unexplained. We performed a proteomic analysis in cultured cortical neurons challenged with either LY379268 or LY354740. Among the few proteins that were differentially influenced by the two drugs, Rab GDP dissociation inhibitor-β (Rab GDIβ) was down-regulated by LY379268 and showed a trend to an up-regulation in response to LY354740. In cultured hippocampal neurons, LY379268 selectively down-regulated the α isoform of Rab GDI. Rab GDI inhibits the activity of the synaptic vesicle-associated protein, Rab3A, and is reduced in the brain of schizophrenic patients. We examined the expression of Rab GDI in mice exposed to prenatal stress ("PRS mice"), which have been described as a putative model of schizophrenia. Rab GDIα protein levels were increased in the hippocampus of PRS mice at postnatal days (PND)1 and 21, but not at PND60. At PND21, PRS mice also showed a reduced depolarization-evoked [(3)H]d-aspartate release in hippocampal synaptosomes. The increase in Rab GDIα levels in the hippocampus of PRS mice was reversed by a 7-days treatment with LY379268 (1 or 10 mg/kg, i.p.), but not by treatment with equal doses of LY354740. These data strengthen the validity of PRS mice as a model of schizophrenia, and show for the first time a pharmacodynamic difference between LY379268 and LY354740 which might be taken into account in an attempt to explain the differential effect of the two drugs across mouse models.

  17. Sound Velocity and Release Behaviour of Shock-Compressed LY12 Al

    Institute of Scientific and Technical Information of China (English)

    YU Yu-Ying; TAN Hua; DAI Cheng-Da; HU Jian-Bo; CHEN Da-Nian

    2005-01-01

    @@ A velocity interferometer system for any reflector (VISAR) is used to measure the sound velocity of LY12 Al shock-compressed to peak pressures of 20, 32, 55 and 71 GPa. Unloading wave velocities from these pressures are obtained from the observed particle velocity profiles at the LY12 Al/LiF window interface; and the longitudinal,bulk and shear sound velocities at the initial Hugoniot state are well determined. The histories of stress, strain,density or volume, and particle velocity along the release paths are calculated by the impedance-matching method based on the unloading sound velocity data. It is revealed that the release behaviour of shocked LY12 Al departures obviously from the elastic perfectly-plastic response.

  18. Human IgG1 Responses to Surface Localised Schistosoma mansoni Ly6 Family Members Drop following Praziquantel Treatment

    Science.gov (United States)

    Chalmers, Iain W.; Fitzsimmons, Colin M.; Brown, Martha; Pierrot, Christine; Jones, Frances M.; Wawrzyniak, Jakub M.; Fernandez-Fuentes, Narcis; Tukahebwa, Edridah M.; Dunne, David W.; Khalife, Jamal; Hoffmann, Karl F.

    2015-01-01

    Background The heptalaminate-covered, syncytial tegument is an important anatomical adaptation that enables schistosome parasites to maintain long-term, intravascular residence in definitive hosts. Investigation of the proteins present in this surface layer and the immune responses elicited by them during infection is crucial to our understanding of host/parasite interactions. Recent studies have revealed a number of novel tegumental surface proteins including three (SmCD59a, SmCD59b and Sm29) containing uPAR/Ly6 domains (renamed SmLy6A SmLy6B and SmLy6D in this study). While vaccination with SmLy6A (SmCD59a) and SmLy6D (Sm29) induces protective immunity in experimental models, human immunoglobulin responses to representative SmLy6 family members have yet to be thoroughly explored. Methodology/Principal Findings Using a PSI-BLAST-based search, we present a comprehensive reanalysis of the Schistosoma mansoni Ly6 family (SmLy6A-K). Our examination extends the number of members to eleven (including three novel proteins) and provides strong evidence that the previously identified vaccine candidate Sm29 (renamed SmLy6D) is a unique double uPAR/Ly6 domain-containing representative. Presence of canonical cysteine residues, signal peptides and GPI-anchor sites strongly suggest that all SmLy6 proteins are cell surface-bound. To provide evidence that SmLy6 members are immunogenic in human populations, we report IgG1 (as well as IgG4 and IgE) responses against two surface-bound representatives (SmLy6A and SmLy6B) within a cohort of S. mansoni-infected Ugandan males before and after praziquantel treatment. While pre-treatment IgG1 prevalence for SmLy6A and SmLy6B differs amongst the studied population (7.4% and 25.3% of the cohort, respectively), these values are both higher than IgG1 prevalence (2.7%) for a sub-surface tegumental antigen, SmTAL1. Further, post-treatment IgG1 levels against surface-associated SmLy6A and SmLy6B significantly drop (p = 0.020 and p < 0

  19. Human IgG1 Responses to Surface Localised Schistosoma mansoni Ly6 Family Members Drop following Praziquantel Treatment.

    Directory of Open Access Journals (Sweden)

    Iain W Chalmers

    Full Text Available The heptalaminate-covered, syncytial tegument is an important anatomical adaptation that enables schistosome parasites to maintain long-term, intravascular residence in definitive hosts. Investigation of the proteins present in this surface layer and the immune responses elicited by them during infection is crucial to our understanding of host/parasite interactions. Recent studies have revealed a number of novel tegumental surface proteins including three (SmCD59a, SmCD59b and Sm29 containing uPAR/Ly6 domains (renamed SmLy6A SmLy6B and SmLy6D in this study. While vaccination with SmLy6A (SmCD59a and SmLy6D (Sm29 induces protective immunity in experimental models, human immunoglobulin responses to representative SmLy6 family members have yet to be thoroughly explored.Using a PSI-BLAST-based search, we present a comprehensive reanalysis of the Schistosoma mansoni Ly6 family (SmLy6A-K. Our examination extends the number of members to eleven (including three novel proteins and provides strong evidence that the previously identified vaccine candidate Sm29 (renamed SmLy6D is a unique double uPAR/Ly6 domain-containing representative. Presence of canonical cysteine residues, signal peptides and GPI-anchor sites strongly suggest that all SmLy6 proteins are cell surface-bound. To provide evidence that SmLy6 members are immunogenic in human populations, we report IgG1 (as well as IgG4 and IgE responses against two surface-bound representatives (SmLy6A and SmLy6B within a cohort of S. mansoni-infected Ugandan males before and after praziquantel treatment. While pre-treatment IgG1 prevalence for SmLy6A and SmLy6B differs amongst the studied population (7.4% and 25.3% of the cohort, respectively, these values are both higher than IgG1 prevalence (2.7% for a sub-surface tegumental antigen, SmTAL1. Further, post-treatment IgG1 levels against surface-associated SmLy6A and SmLy6B significantly drop (p = 0.020 and p < 0.001, respectively when compared to rising Ig

  20. A submillimeter galaxy illuminating its circumgalactic medium: Lyα scattering in a cold, clumpy outflow

    Energy Technology Data Exchange (ETDEWEB)

    Geach, J. E.; Coppin, K. E. K.; Smith, D. J. B. [Center for Astrophysics Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Bower, R. G.; Alexander, D. M.; Swinbank, A. M. [Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Blain, A. W. [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Bremer, M. N. [School of Physics, HH Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Chapin, E. L. [XMM SOC, ESAC, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Chapman, S. C. [Department of Physics and Atmospheric Science, Dalhousie University Halifax, NS B3H 3J5 (Canada); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Dunlop, J. S.; Koprowski, M. P.; Michałowski, M. J. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Farrah, D. [Virginia Polytechnic Institute and State University Department of Physics, MC 0435, 910 Drillfield Drive, Blacksburg, VA 24061 (United States); Jenness, T. [Joint Astronomy Centre, 660 North A' ohoku Place University Park, Hilo, HI 96720 (United States); Robson, E. I. [UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Scott, D. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Spaans, M. [Kapteyn Institute, University of Groningen, PO Box 800, 9700 AV Groningen (Netherlands); Van der Werf, P., E-mail: j.geach@herts.ac.uk [Leiden Observatory, Leiden University, PO box 9513, 2300 RA Leiden (Netherlands)

    2014-09-20

    We report the detection at 850 μm of the central source in SSA22-LAB1, the archetypal 'Lyman-α Blob' (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S {sub 850} = 4.6 ± 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L {sub IR} ≈ 10{sup 12} L {sub ☉}. The position of an active source at the center of a ∼50 kpc radius ring of linearly polarized Lyα emission detected by Hayes et al. suggests that the central source is leaking Lyα photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Lyα morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Lyα line profiles of the two 'lobes' are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Lyα emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Lyα: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?.

  1. arXiv Neutrino masses and cosmology with Lyman-alpha forest power spectrum

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Baur, Julien; Magneville, Christophe; Rossi, Graziano; Lesgourgues, Julien; Borde, Arnaud; Burtin, Etienne; LeGoff, Jean-Marc; Rich, James; Viel, Matteo; Weinberg, David

    2015-01-01

    We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the $\\Lambda$CDM model, using the one-dimensional Ly$\\alpha$-forest power spectrum measured by Palanque-Delabrouille et al. (2013) from SDSS-III/BOSS, complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by Palanque-Delabrouille et al. (2015) by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Ly$\\alpha$ data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ...

  2. 三 干扰素-α(interferon alpha,IFN-α)

    Institute of Scientific and Technical Information of China (English)

    张丽兰

    2007-01-01

    @@ 1概述 干扰素-α历史上曾用名为:B-细胞干扰素(Bcell interferon);血浆沉淀淡黄色表层干扰素(Buffy coat interferon);外源性细胞干扰素(Foreign cellinduced interferon);白细胞干扰素(Leukocyte interferon,LeIFN);淋巴母细胞干扰素(Lymphoblast interferon,LyIFN-alpha);类淋巴母细胞干扰素(Lymphoblastoid interferon,LyIFN-alpha);Namalwa细胞干扰素(Namalwa interferon);pH2-稳定干扰素(pH2-stable interferon);Ⅰ型干扰素(Type-1 interferon);RSV-诱导因子(RSV-induced factor).

  3. The Signatures of Large-scale Temperature Fluctuations in the Lyman-alpha Forest

    CERN Document Server

    McQuinn, Matthew; Lidz, Adam; Zaldarriaga, Matias

    2010-01-01

    It appears inevitable that reionization processes would have produced large-scale temperature fluctuations in the intergalactic medium. Using toy temperature models and detailed heating histories in cosmological simulations of HeII reionization, we study the consequences of inhomogeneous heating for the Ly-alpha forest. The impact of temperature fluctuations in physically well-motivated models can be surprisingly subtle. In fact, we show that temperature fluctuations at the level predicted by our reionization simulations do not give rise to detectable signatures in the types of statistics that have been employed previously. However, because of the aliasing of small-scale density power to larger scale modes in the line-of-sight Ly-alpha forest power spectrum, earlier analyses were not sensitive to 3D modes with >~ 30 comoving Mpc wavelengths -- scales where temperature fluctuations are likely to be relatively largest. The ongoing Baryon Oscillation Spectroscopic Survey (BOSS) aims to measure the 3D power spect...

  4. High-ion absorption in the proximate damped Lyman-alpha system toward Q0841+129

    CERN Document Server

    Fox, Andrew J; Petitjean, Patrick; Srianand, Raghunathan; Guimarães, Rodney

    2011-01-01

    We present VLT/UVES spectroscopy of the quasar Q0841+129, whose spectrum shows a proximate damped Lyman-alpha (PDLA) absorber at z=2.47621 and a proximate sub-DLA at z=2.50620, both lying close in redshift to the QSO itself at z_em=2.49510+/-0.00003. This fortuitous arrangement, with the sub-DLA acting as a filter that hardens the QSO's ionizing radiation field, allows us to model the ionization level in the foreground PDLA, and provides an interesting case-study on the origin of the high-ion absorption lines Si IV, C IV, and O VI in DLAs. The high ions in the PDLA show at least five components spanning a total velocity extent of ~160 km/s, whereas the low ions exist predominantly in a single component spanning just 30 km/s. We examine various models for the origin of the high ions. Both photoionization and turbulent mixing layer models are fairly successful at reproducing the observed ionic ratios after correcting for the non-solar relative abundance pattern, though neither model can explain all five compone...

  5. Cosmological and astrophysical parameters from the SDSS flux power spectrum and hydrodynamical simulations of the Lyman-alpha forest

    CERN Document Server

    Viel, M; Viel, Matteo; Haehnelt, Martin G.

    2006-01-01

    (abridged) The flux power spectrum of the Lyman-alpha forest in quasar (QSO) absorption spectra is sensitive to a wide range of cosmological and astrophysical parameters and instrumental effects. Modelling the flux power spectrum in this large parameter space to an accuracy comparable to the statistical uncertainty of large samples of QSO spectra is very challenging. We use here a coarse grid of hydrodynamical simulations run with GADGET-2 to obtain a ``best guess'' model around which we calculate a finer grid of flux power spectra using a Taylor expansion of the flux power spectrum to first order. We find that the SDSS flux power spectrum alone is able to constrain a wide range of parameters including the amplitude of the matter power spectrum sigma_8, the matter density Omega_m, the spectral index of primordial density fluctuations n, the effective optical depth tau_eff and its evolution. The thermal history of the Intergalactic Medium (IGM) is, however, poorly constrained and the SDSS data favour either an...

  6. Pinpointing the molecular gas within an Lyα blob at z ∼ 2.7

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yujin; Bertoldi, Frank; Bădescu, Toma [Argelander Institut für Astronomie, Universität Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany); Walter, Fabian; Decarli, Roberto [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Weiss, Axel [Max-Planck-Insitut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Dey, Arjun [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Prescott, Moire K. M. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark)

    2014-04-01

    We present IRAM Plateau de Bure Interferometer observations of the CO(3-2) and CO(5-4) line transitions from an Lyα blob at z ∼ 2.7 in order to investigate the gas kinematics, determine the location of the dominant energy source, and study the physical conditions of the molecular gas. CO line and dust continuum emissions are detected at the location of a strong MIPS source that is offset by ∼1.''5 from the Lyα peak. Neither of these emission components is resolved with the 1.''7 beam, showing that the gas and dust are confined to within ∼7 kpc from this galaxy. No millimeter source is found at the location of the Lyα peak, ruling out a central compact source of star formation as the power source for the Lyα emission. Combined with a spatially resolved spectrum of Lyα and He II, we constrain the kinematics of the extended gas using the CO emission as a tracer of the systemic redshift. Near the MIPS source, the Lyα profile is symmetric, and its line center agrees with that of the CO line, implying that there are no significant bulk flows and that the photo-ionization from the MIPS source might be the dominant source of the Lyα emission. In the region near the Lyα peak, the gas is slowly receding (∼100 km s{sup –1}) with respect to the MIPS source, thus making the hyper-/superwind hypothesis unlikely. We find a sub-thermal line ratio between two CO transitions, I {sub CO(5-4)}/I {sub CO(3-2)} = 0.97 ± 0.21. This line ratio is lower than the average values found in high-z submillimeter galaxies and QSOs but is consistent with the value found in the Galactic center, suggesting that there is a large reservoir of low-density molecular gas that is spread over the MIPS source and its vicinity.

  7. The HETDEX Pilot Survey V: The Physical Origin of Lyman-alpha Emitters Probed by Near-infrared Spectroscopy

    CERN Document Server

    Song, Mimi; Gebhardt, Karl; Hill, Gary J; Drory, Niv; Ashby, Matthew L N; Blanc, Guillermo A; Bridge, Joanna; Chonis, Taylor; Ciardullo, Robin; Fabricius, Maximilian; Fazio, Giovanni G; Gawiser, Eric; Gronwall, Caryl; Hagen, Alex; Huang, Jia-Sheng; Jogee, Shardha; Livermore, Rachael; Salmon, Brett; Schneider, Donald P; Willner, S P; Zeimann, Gregory R

    2014-01-01

    We present the results from a VLT/SINFONI and Keck/NIRSPEC near-infrared spectroscopic survey of 16 Lyman-alpha emitters (LAEs) at $z$ = 2.1 - 2.5 in the COSMOS and GOODS-N fields discovered from the HETDEX Pilot Survey. We detect rest-frame optical nebular lines (H$\\alpha$ and/or [OIII]$\\lambda$5007) for 10 of the LAEs and measure physical properties, including the star formation rate (SFR), gas-phase metallicity, gas-mass fraction, and Ly$\\alpha$ velocity offset. We find that LAEs may lie below the mass-metallicity relation for continuum-selected star-forming galaxies at the same redshift. The LAEs all show velocity shifts of Ly$\\alpha$ relative to the systemic redshift ranging between +85 and +296 km s$^{-1}$ with a mean of +180 km s$^{-1}$. This value is smaller than measured for continuum-selected star-forming galaxies at similar redshifts. The Ly$\\alpha$ velocity offsets show a moderate correlation with the measured star formation rate (2.5$\\sigma$), but no significant correlations are seen with the SFR...

  8. Statistical properties of diffuse Lyα haloes around star-forming galaxies at z ˜ 2

    Science.gov (United States)

    Momose, Rieko; Ouchi, Masami; Nakajima, Kimihiko; Ono, Yoshiaki; Shibuya, Takatoshi; Shimasaku, Kazuhiro; Yuma, Suraphong; Mori, Masao; Umemura, Masayuki

    2016-04-01

    We present statistical properties of diffuse Lyα haloes (LAHs) around high-z star-forming galaxies with large Subaru samples of Lyα emitters (LAEs) at z = 2.2. We make subsamples defined by the physical quantities of LAEs' central Lyα luminosities, ultraviolet (UV) magnitudes, Lyα equivalent widths, and UV slopes, and investigate LAHs' radial surface brightness (SB) profiles and scale lengths rn as a function of these physical quantities. We find that there exist prominent LAHs around LAEs with faint Lyα luminosities, bright UV luminosities, and small Lyα equivalent widths in cumulative radial Lyα SB profiles. We confirm this trend with the anticorrelation between rn and Lyα luminosities (equivalent widths) based on the Spearman's rank correlation coefficient that is ρ = -0.9 (-0.7) corresponding to the 96 per cent (93 per cent) confidence level, although the correlation between rn and UV magnitudes is not clearly found in the rank correlation coefficient. Our results suggest that LAEs with properties similar to typical Lyman-break galaxies (with faint Lyα luminosities and small equivalent widths) possess more prominent LAHs. We investigate scenarios for the major physical origins of LAHs with our results. Because we find relatively small Lyα equivalent widths up to 77 Å in LAHs that include LAEs' central components, these results suggest that the cold stream scenario is not preferred. There remain two possible scenarios of Lyα scattering in circumgalactic medium and satellite galaxies that cannot be tested with our observational data.

  9. 海洋链霉菌LY-1的抗细菌特性研究%Antibacterial Property of Marine Streptomlyces sp. LY-1

    Institute of Scientific and Technical Information of China (English)

    刘姝; 房耀维; 徐炜枫; 吕明生; 王淑军; 陈丽

    2009-01-01

    从连云港海域潮间带所采的土样中分离到一株产高活性抗细菌物质的链霉菌LY-1.抗菌谱测定结果表明菌株LY-1发酵产物对枯草芽孢杆菌等5株革兰氏阳性菌,大肠杆菌等6株革兰氏阴性菌有显著拮抗作用.稳定性研究表明该菌所产抗细菌物质在121℃,pH1和pH12条件下抑菌活性均小变;紫外线照射也不影响其抑细菌活性.该抗菌产物对蜡样芽孢杆菌和大肠杆菌生长的抑制作用研究表明,该抗菌产物能够较好的抑制蜡样芽孢杆菌和大肠杆菌的生长繁殖.菌株LY-1所产抗菌物质在海产品及食品保鲜、生防及医药方面具有潜在的应用价值.

  10. The mGlu2/3 Receptor Agonists LY354740 and LY379268 Differentially Regulate Restraint-Stress-Induced Expression of c-Fos in Rat Cerebral Cortex

    Directory of Open Access Journals (Sweden)

    M. M. Menezes

    2013-01-01

    Full Text Available Metabotropic glutamate 2/3 (mGlu2/3 receptors have emerged as potential therapeutic targets due to the ability of mGlu2/3 receptor agonists to modulate excitatory transmission at specific synapses. LY354740 and LY379268 are selective and potent mGlu2/3 receptor agonists that show both anxiolytic- and antipsychotic-like effects in animal models. We compared the efficacy of LY354740 and LY379268 in attenuating restraint-stress-induced expression of the immediate early gene c-Fos in the rat prelimbic (PrL and infralimbic (IL cortex. LY354740 (10 and 30 mg/kg, i.p. showed statistically significant and dose-related attenuation of stress-induced increase in c-Fos expression, in the rat cortex. By contrast, LY379268 had no effect on restraint-stress-induced c-Fos upregulation (0.3–10 mg/kg, i.p.. Because both compounds inhibit serotonin 2A receptor (5-HT2AR-induced c-Fos expression, we hypothesize that LY354740 and LY379268 have different in vivo properties and that 5-HT2AR activation and restraint stress induce c-Fos through distinct mechanisms.

  11. Accelerated Evolution of Ly$\\alpha$ Luminosity Function at $\\textit{z} \\gtrsim 7$ Revealed by the Subaru Ultra-Deep Survey for Ly$\\alpha$ Emitters at $\\textit{z}=7.3$

    CERN Document Server

    Konno, Akira; Ono, Yoshiaki; Shimasaku, Kazuhiro; Shibuya, Takatoshi; Furusawa, Hisanori; Nakajima, Kimihiko; Naito, Yoshiaki; Momose, Rieko; Yuma, Suraphong; Iye, Masanori

    2014-01-01

    We present the ultra-deep Subaru narrowband imaging survey for Lya emitters (LAEs) at $z=7.3$ in SXDS and COSMOS fields with a total integration time of 106 hours. Exploiting our new sharp bandwidth filter, NB101, installed on Suprime-Cam, we have reached $L(Lya)=2.4\\times10^{42} \\ erg \\ s^{-1}$ ($5\\sigma$) for $z=7.3$ LAEs, about 4 times deeper than previous Subaru $z \\gtrsim 7$ studies, which allows us to reliably investigate evolution of Lya luminosity function (LF), for the first time, down to the luminosity limit same as those of Subaru $z=3.1-6.6$ LAE samples. Surprisingly, we only find three and four LAEs in SXDS and COSMOS fields, respectively, while one expects a total of $\\sim 65$ LAEs by our survey in the case of no Lya LF evolution from $z=6.6$ to $7.3$.We identify a decrease of Lya LF from $z=6.6$ to $7.3$ at the $>90\\%$ confidence level from our $z=7.3$ Lya LF.Moreover, the evolution of Lya LF is clearly accelerated at $z>6.6$ beyond the measurement uncertainties including cosmic variance. Becau...

  12. The Lyman alpha reference sample. VII. Spatially resolved Hα kinematics

    Science.gov (United States)

    Herenz, Edmund Christian; Gruyters, Pieter; Orlitova, Ivana; Hayes, Matthew; Östlin, Göran; Cannon, John M.; Roth, Martin M.; Bik, Arjan; Pardy, Stephen; Otí-Floranes, Héctor; Mas-Hesse, J. Miguel; Adamo, Angela; Atek, Hakim; Duval, Florent; Guaita, Lucia; Kunth, Daniel; Laursen, Peter; Melinder, Jens; Puschnig, Johannes; Rivera-Thorsen, Thøger E.; Schaerer, Daniel; Verhamme, Anne

    2016-03-01

    We present integral field spectroscopic observations with the Potsdam Multi-Aperture Spectrophotometer of all 14 galaxies in the z ~ 0.1 Lyman Alpha Reference Sample (LARS). We produce 2D line-of-sight velocity maps and velocity dispersion maps from the Balmer α (Hα) emission in our data cubes. These maps trace the spectral and spatial properties of the LARS galaxies' intrinsic Lyα radiation field. We show our kinematic maps that are spatially registered onto the Hubble Space Telescope Hα and Lyman α (Lyα) images. We can conjecture a causal connection between spatially resolved Hα kinematics and Lyα photometry for individual galaxies, however, no general trend can be established for the whole sample. Furthermore, we compute the intrinsic velocity dispersion σ0, the shearing velocity vshear, and the vshear/σ0 ratio from our kinematic maps. In general LARS galaxies are characterised by high intrinsic velocity dispersions (54 km s-1 median) and low shearing velocities (65 km s-1 median). The vshear/σ0 values range from 0.5 to 3.2 with an average of 1.5. It is noteworthy that five galaxies of the sample are dispersion-dominated systems with vshear/σ0 1. Our result indicates that turbulence in actively star-forming systems is causally connected to interstellar medium conditions that favour an escape of Lyα radiation. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC).The reduced data cubes (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/587/A78

  13. Mouse novel Ly9: a new member of the expanding CD150 (SLAM) family of leukocyte cell-surface receptors.

    Science.gov (United States)

    Tovar, Victoria; del Valle, Juana; Zapater, Nuria; Martin, Margarita; Romero, Xavier; Pizcueta, Pilar; Bosch, Jaime; Terhorst, Cox; Engel, Pablo

    2002-09-01

    Human CS1, also known as novel Ly9, 19A24, or CRACC, is a member of the immunoglobulin gene superfamily (IgSF) expressed on natural killer cells and other leukocytes. Here we describe the cloning of the mouse homologue of this gene. The mouse novel Ly9 gene is shown to encode a transmembrane protein composed of two extracellular immunoglobulin-like domains, a transmembrane region and an 88-amino acid cytoplasmic domain. Mouse novel Ly9 is structurally similar to the extracellular domains of CD84 and CD229 (Ly9). Both mouse and human novel Ly9 genes mapped close to the CD229gene in a region where other members of the CD150 family have also been mapped, and analysis of their genomic sequences showed that they have an identical intron/exon organization. Northern blot analysis revealed that the expression of mouse and human novel Ly9 was predominantly restricted to hematopoietic tissues, with the exception of testis. Here we show that SAP (SH2D1A), an adapter protein responsible for the X-linked lymphoproliferative disease, binds to the phosphorylated cytoplasmic tail of human but not mouse novel Ly9. Taken together, these data indicate that mouse novel Ly9 is a new member of the expanding CD150 family of cell surface receptors.

  14. The VLT LBG Redshift Survey - V. Characterising the z = 3.1 Lyman Alpha Emitter Population

    CERN Document Server

    Bielby, R M; Shanks, T; Francke, H; Crighton, N H M; Bañados, E; González-López, Jorge; Infante, L; Orsi, A

    2016-01-01

    We present a survey of Ly$\\alpha$ emitting galaxies in the fields of the VLT LBG Redshift Survey, incorporating the analysis of narrow band number counts, the rest frame UV luminosity function and the two-point correlation function of Ly$\\alpha$ emitters at $z\\approx3.1$. Our photometric sample consists of 750 LAE candidates, over an area of 1.07 deg$^2$, with estimated equivalent widths of $\\gtrsim65$ \\AA, from 5 fields based on deep Subaru Suprime-Cam imaging data. Added to this we have obtained spectroscopic follow-up observations, which successfully detected Ly$\\alpha$ emission in 35 galaxies. Based on the spectroscopic results, we refined our photometric selection constraints, with the resulting sample having a success rate of $78\\pm18\\%$. We calculate the narrow band number counts for our photometric sample and find these to be consistent with previous studies of LAEs at this redshift. We find the $R$-band continuum luminosity function to be $\\sim10\\times$ lower than the equivalent luminosity function o...

  15. Strong Field-to-Field Variation of Lyman alpha Nebulae Populations at z~2.3

    CERN Document Server

    Yang, Yujin; Eisenstein, Daniel; Davé, Romeel

    2010-01-01

    Understanding the nature of distant Ly-alpha nebulae ("blobs") and connecting them to their present-day descendants requires constraining their number density, clustering, and large-scale environment. To measure these basic quantities, we conduct a deep narrowband imaging survey in four different fields, Chandra Deep Field South (CDFS), Chandra Deep Field North, and two COSMOS subfields, for a total survey area of 1.2deg^2. We discover 25 blobs at z=2.3 with Ly-alpha luminosities of 0.7-8x10^43 erg/s and isophotal areas of Aiso = 10-60 arcsec^2. The transition from compact Ly-alpha emitters (Aiso ~ a few arcsec^2) to extended blobs (Aiso > 10 arcsec^2) is continuous, suggesting a single family perhaps governed by similar emission mechanisms. Surprisingly, most blobs (16/25) are in one survey field, the CDFS. The six brightest, largest blobs with L > 1.5x10^43 erg/s and Aiso > 16 arcsec^2 lie only in the CDFS. These large, bright blobs have a field-to-field variance of sigma_v >~ 1.5 (150%) about their number ...

  16. Mapping the Polarization of the Radio-Loud Ly$\\alpha$ Nebula B3 J2330+3927

    CERN Document Server

    You, Chang; Smith, Paul; Yang, Yujin; Kim, Eunchong; Jannuzi, Buell; Prescott, Moire K M; Matsuda, Yuichi; Lee, Myung Gyoon

    2016-01-01

    Lya nebulae, or "Lya blobs", are extended (up to ~100 kpc), bright (L[Lya] > 10^43 erg/s) clouds of Lya emitting gas that tend to lie in overdense regions at z ~ 2--5. The origin of the Lya emission remains unknown, but recent theoretical work suggests that measuring the polarization might discriminate among powering mechanisms. Here we present the first narrowband, imaging polarimetry of a radio-loud Lya nebula, B3 J2330+3927 at z=3.09, with an embedded active galactic nucleus (AGN). The AGN lies near the blob's Lya emission peak and its radio lobes align roughly with the blob's major axis. With the SPOL polarimeter on the 6.5m MMT telescope, we map the total (Lya + continuum) polarization in a grid of circular apertures of radius 0.6" (4.4kpc), detecting a significant (>2sigma) polarization fraction P in nine apertures and achieving strong upper-limits (as low as 2%) elsewhere. P increases from <2% at ~5kpc from the blob center to ~17% at ~15-25kpc. The detections are distributed asymmetrically, roughly ...

  17. Model Insensitive and Calibration Independent Method for Determination of the Downstream Neutral Hydrogen Density Through Ly-alpha Glow Observations

    Science.gov (United States)

    Gangopadhyay, P.; Judge, D. L.

    1996-01-01

    Our knowledge of the various heliospheric phenomena (location of the solar wind termination shock, heliopause configuration and very local interstellar medium parameters) is limited by uncertainties in the available heliospheric plasma models and by calibration uncertainties in the observing instruments. There is, thus, a strong motivation to develop model insensitive and calibration independent methods to reduce the uncertainties in the relevant heliospheric parameters. We have developed such a method to constrain the downstream neutral hydrogen density inside the heliospheric tail. In our approach we have taken advantage of the relative insensitivity of the downstream neutral hydrogen density profile to the specific plasma model adopted. We have also used the fact that the presence of an asymmetric neutral hydrogen cavity surrounding the sun, characteristic of all neutral densities models, results in a higher multiple scattering contribution to the observed glow in the downstream region than in the upstream region. This allows us to approximate the actual density profile with one which is spatially uniform for the purpose of calculating the downstream backscattered glow. Using different spatially constant density profiles, radiative transfer calculations are performed, and the radial dependence of the predicted glow is compared with the observed I/R dependence of Pioneer 10 UV data. Such a comparison bounds the large distance heliospheric neutral hydrogen density in the downstream direction to a value between 0.05 and 0.1/cc.

  18. HST/COS Observations of the Ly alpha Forest toward the BL Lac Object 1ES1553+113

    CERN Document Server

    Danforth, Charles W; Stocke, John T; Shull, J Michael; Yao, Yangsen

    2010-01-01

    We present new far-ultraviolet spectra from the Cosmic Origins Spectrograph (HST/COS) of the BL Lac object 1ES1553+113 covering the wavelength range 1135-1795 A. The data show a smooth continuum with a wealth of narrow absorption features arising in the ISM and IGM. These features include 41 Lya absorbers at 00.6 for the strongest component of the absorber complex. Galaxy redshift surveys show a number of massive galaxies at approximately the same redshift as this absorption complex, suggesting that it arises in a large-scale galaxy filament. As one of the brightest extragalactic X-ray and gamma-ray sources, 1ES1553+113 is of great interest to the high-energy astrophysics community. With no intrinsic emission or absorption features, 1ES1553+113 has no direct redshift determination. We use intervening Lya absorbers to place a direct limit on the redshift: z_em>0.395 based on a confirmed Lya+OVI absorber and z_em>0.433 based on a single-line detection of Lya. COS/FUV data are only sensitive to Lya absorbers at ...

  19. A New Constraint on the Ly$\\alpha$ Fraction of UV Very Bright Galaxies at Redshift 7

    CERN Document Server

    Furusawa, Hisanori; Kobayashi, Masakazu A R; Dunlop, James S; Shimasaku, Kazuhiro; Takata, Tadafumi; Sekiguchi, Kazuhiro; Naito, Yoshiaki; Furusawa, Junko; Ouchi, Masami; Nakata, Fumiaki; Yasuda, Naoki; Okura, Yuki; Taniguchi, Yoshiaki; Yamada, Toru; Kajisawa, Masaru; Fynbo, Johan P U; Fevre, Olivier Le

    2016-01-01

    We study the extent to which very bright (-23.0 50 Angstrom, which we estimate to be < 0.23. This result may indicate a weak trend where the fraction of strong Lya emitters ceases to rise, and possibly falls between z~6 and z~7. Our results also leave open the possibility that strong Lya may still be more prevalent in the brightest galaxies in the reionization era than their fainter counterparts. A larger spectroscopic sample of galaxies is required to derive a more reliable constraint on the neutral hydrogen fraction at z~7 based on the Lya fraction in the bright galaxies.

  20. VizieR Online Data Catalog: UCSD/Keck Damped Ly{alpha} Abundance Database (Prochaska+, 2007)

    Science.gov (United States)

    Prochaska, J. X.; Wolfe, A. M.; Howk, J. C.; Gawiser, E.; Burles, S. M.; Cooke, J.

    2009-04-01

    For nearly all observations, the HIRES spectra were acquired using either a 0.8" or 1.1" wide decker (FWHM about 6 and 8km/s, respectively) and the ESI observations were carried out with the 0.5" or 0.75" slit (FWHM about 33 and 44km/s, respectively). All of the HIRES spectra were acquired with the original Tektronix 2048*2048CCD. In general we strove to achieve a final signal-to-noise ratio (S/N) of >15pixel-1^ (2km/s/pix for HIRES, 11km/s/pix for ESI). ESI has a fixed format that covers the spectral region {lambda}=4000 to 10000{AA}. (2 data files).

  1. Nonclassical Ly6C− Monocytes Drive the Development of Inflammatory Arthritis in Mice

    Directory of Open Access Journals (Sweden)

    Alexander V. Misharin

    2014-10-01

    Full Text Available Different subsets and/or polarized phenotypes of monocytes and macrophages may play distinct roles during the development and resolution of inflammation. Here, we demonstrate in a murine model of rheumatoid arthritis that nonclassical Ly6C− monocytes are required for the initiation and progression of sterile joint inflammation. Moreover, nonclassical Ly6C− monocytes differentiate into inflammatory macrophages (M1, which drive disease pathogenesis and display plasticity during the resolution phase. During the development of arthritis, these cells polarize toward an alternatively activated phenotype (M2, promoting the resolution of joint inflammation. The influx of Ly6C− monocytes and their subsequent classical and then alternative activation occurs without changes in synovial tissue-resident macrophages, which express markers of M2 polarization throughout the course of the arthritis and attenuate joint inflammation during the initiation phase. These data suggest that circulating Ly6C− monocytes recruited to the joint upon injury orchestrate the development and resolution of autoimmune joint inflammation.

  2. Corrosion behavior on aluminum alloy LY12 in simulated atmospheric corrosion process

    Institute of Scientific and Technical Information of China (English)

    WANG Zhen-yao; MA Teng; HAN Wei; YU Guo-cai

    2007-01-01

    The corrosion behavior of typical high-strength aluminum alloy LY12 was studied by accelerated corrosion tests of cyclic wet-dry-immersion containing media of NaHSO3 and NaCl to simulate the corrosion process in different atmosphere environment, and the corrosion mechanism was also discussed. The main experimental techniques include mass loss, morphological check, analysis of corrosion products and electrochemical measurement. The result shows that the mass loss of LY12, with or without cladding, has linear relationship with test time in the three kinds of chemical media, 0.02 mol/L NaHSO3, 0.006 mol/L NaCl and 0.02 mol/L NaHSO3+0.006 mol/L NaCl, respectively. A layer of cladding on high-strength aluminum alloy can raise evidently the resistance of atmospheric corrosion. Cl- can promote pitting generation on the oxide film of LY12 when HOS3- exists, LY12 can react much intensely with HOS3- derived from anions.

  3. Interaktiivne võrguõpik "Võnkumised ja lained" / Ly Sõõrd

    Index Scriptorium Estoniae

    Sõõrd, Ly

    2000-01-01

    Interaktiivne võrguõpik "Võnkumised ja lained" on mõeldud gümnaasiumi 10. kl. füüsikakursuse osa "Mehaanilised võnkumised ja lained" õppimiseks iseseisvalt interneti vahendusel ning asub aadressil : http://www.physic.ut.ee/̃ly/xklass/opik.html

  4. Interaktiivne võrguõpik "Võnkumised ja lained" / Ly Sõõrd

    Index Scriptorium Estoniae

    Sõõrd, Ly

    2000-01-01

    Interaktiivne võrguõpik "Võnkumised ja lained" on mõeldud gümnaasiumi 10. kl. füüsikakursuse osa "Mehaanilised võnkumised ja lained" õppimiseks iseseisvalt interneti vahendusel ning asub aadressil : http://www.physic.ut.ee/̃ly/xklass/opik.html

  5. A Luminosity Function of Lyα-emitting Galaxies at z ~ 4.5

    Science.gov (United States)

    Dawson, Steve; Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel; Wang, JunXian; Dey, Arjun; Spinrad, Hyron; Jannuzi, Buell T.

    2007-12-01

    We present a catalog of 59 z~4.5 Lyα-emitting galaxies spectroscopically confirmed in a campaign of Keck DEIMOS follow-up observations to candidates selected in the Large Area Lyα (LALA) narrowband imaging survey. We targeted 97 candidates for spectroscopic follow-up by accounting for the variety of conditions under which we performed spectroscopy, we estimate a selection reliability of ~76%. Together with our previous sample of Keck LRIS confirmations, the 59 sources confirmed herein bring the total catalog to 73 spectroscopically confirmed z~4.5 Lyα-emitting galaxies in the ~0.7 deg2 covered by the LALA imaging. As with the Keck LRIS sample, we find that a nonnegligible fraction of the confirmed Lyα lines have rest-frame equivalent widths (Wrestλ) that exceed the maximum predicted for normal stellar populations: 17%-31% (93% confidence) of the detected galaxies show Wrestλ>190 Å, and 12%-27% (90% confidence) show Wrestλ>240 Å. We construct a luminosity function of z~4.5 Lyα emission lines for comparison to Lyα luminosity functions spanning 3.1Lyα luminosity function evolution from z~3 to z~6. This result supports the conclusion that the intergalactic medium remains largely reionized from the local universe out to z~6.5. It is somewhat at odds with the pronounced drop in the cosmic star formation rate density recently measured between z~3 and z~6 in continuum-selected Lyman-break galaxies, and therefore potentially sheds light on the relationship between the two populations. Based in part on observations made at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. Our data were obtained using community access telescope time made available under the National

  6. Ab initio alpha-alpha scattering

    CERN Document Server

    Elhatisari, Serdar; Rupak, Gautam; Epelbaum, Evgeny; Krebs, Hermann; Lähde, Timo A; Luu, Thomas; Meißner, Ulf-G

    2015-01-01

    Processes involving alpha particles and alpha-like nuclei comprise a major part of stellar nucleosynthesis and hypothesized mechanisms for thermonuclear supernovae. In an effort towards understanding alpha processes from first principles, we describe in this letter the first ab initio calculation of alpha-alpha scattering. We use lattice effective field theory to describe the low-energy interactions of nucleons and apply a technique called the adiabatic projection method to reduce the eight-body system to an effective two-cluster system. We find good agreement between lattice results and experimental phase shifts for S-wave and D-wave scattering. The computational scaling with particle number suggests that alpha processes involving heavier nuclei are also within reach in the near future.

  7. TRANSITING THE SUN. II. THE IMPACT OF STELLAR ACTIVITY ON Lyα TRANSITS

    Energy Technology Data Exchange (ETDEWEB)

    Llama, J.; Shkolnik, E. L., E-mail: joe.llama@lowell.edu [Lowell Observatory, 1400 W Mars Hill Road, Flagstaff, AZ 86001 (United States)

    2016-01-20

    High-energy observations of the Sun provide an opportunity to test the limits of our ability to accurately measure the properties of transiting exoplanets in the presence of stellar activity. Here we insert the transit of a hot Jupiter into continuous disk integrated data of the Sun in Lyα from NASA’s Solar Dynamics Observatory/EVE instrument to assess the impact of stellar activity on the measured planet-to-star radius ratio (R{sub p}/R{sub ⋆}). In 75% of our simulated light curves, we measure the correct radius ratio; however, incorrect values can be measured if there is significant short-term variability in the light curve. The maximum measured value of R{sub p}/R{sub ⋆} is 50% larger than the input value, which is much smaller than the large Lyα transit depths that have been reported in the literature, suggesting that for stars with activity levels comparable to the Sun, stellar activity alone cannot account for these deep transits. We ran simulations without a transit and found that stellar activity cannot mimic the Lyα transit of 55 Cancari b, strengthening the conclusion that this planet has a partially transiting exopshere. We were able to compare our simulations to more active stars by artificially increasing the variability in the Solar Lyα light curve. In the higher variability data, the largest value of R{sub p}/R{sub ⋆} we measured is <3× the input value, which again is not large enough to reproduce the Lyα transit depth reported for the more active stars HD 189733 and GJ 436, supporting the interpretation that these planets have extended atmospheres and possible cometary tails.

  8. Polarization of Rayleigh scattered Lyα in active galactic nuclei

    Science.gov (United States)

    Chang, Seok-Jun; Lee, Hee-Won; Yang, Yujin

    2017-02-01

    The unification scheme of active galactic nuclei invokes an optically thick molecular torus component hiding the broad emission line region. Assuming the presence of a thick neutral component in the molecular torus characterized by a H I column density >1022 cm-2, we propose that far-UV radiation around Lyα can be significantly polarized through Rayleigh scattering. Adopting a Monte Carlo technique, we compute polarization of Rayleigh scattered radiation near Lyα in a thick neutral region in the shape of a slab and a cylindrical shell. It is found that radiation near Lyα Rayleigh reflected from a very thick slab can be significantly polarized in a fairly large range of wavelength Δλ ˜ 50 Å exhibiting a flux profile similar to the incident one. Rayleigh transmitted radiation in a slab is characterized by the central dip with a complicated polarization behaviour. The optically thick part near Lyα centre is polarized in the direction perpendicular to the slab normal, which is in contrast to weakly polarized wing parts in the direction parallel to the slab normal. A similar polarization flip phenomenon is also found in the case of a tall cylindrical shell, in which the spatial diffusion along the vertical direction near the inner cylinder wall for core photons leads to a tendency of the electric field aligned to the direction perpendicular to the vertical axis. Observational implications are briefly discussed including spectropolarimetry of the quasar PG 1630+377 by Koratkar et al. in 1990 where Lyα is strongly polarized with no other emission lines polarized.

  9. The effect of Lyman $\\alpha$ radiation on mini-Neptune atmospheres around M stars: application to GJ 436b

    CERN Document Server

    Miguel, Yamila; Linsky, Jeffrey L; Rugheimer, Sarah

    2014-01-01

    Mini-Neptunes orbiting M stars are a growing population of known exoplanets. Some of them are located very close to their host star, receiving large amounts of UV radiation. Many M stars emit strong chromospheric emission in the H I Lyman $\\alpha$ line (Ly$\\alpha$) at 1215.67 \\AA, the brightest far-UV emission line. We show that the effect of incoming Ly$\\alpha$ flux can significantly change the photochemistry of mini-Neptunes' atmospheres. We use GJ 436b as an example, considering different metallicities for its atmospheric composition. For solar composition, H$_2$O-mixing ratios show the largest change because of Ly$\\alpha$ radiation. H$_2$O absorbs most of this radiation, thereby shielding CH$_4$, whose dissociation is driven mainly by radiation at other far-UV wavelengths ($\\sim1300$ \\AA). H$_2$O photolysis also affects other species in the atmosphere, including H, H$_2$, CO$_2$, CO, OH and O. For an atmosphere with high metallicity, H$_2$O- and CO$_2$-mixing ratios show the biggest change, thereby shield...

  10. More than Solfège and Hand Signs: Philosophy, Tools, and Lesson Planning in the Authentic Kodály Classroom

    Science.gov (United States)

    Bowyer, James

    2015-01-01

    Four components of the Kodály concept are delineated here: philosophy, objectives, essential tools, and lesson planning process. After outlining the tenets of the Kodály philosophy and objectives, the article presents the Kodály concept's essential tools, including singing, movable "do" solfège, rhythm syllables, hand signs, singing on…

  11. LY294002白蛋白结合型纳米注射剂的制备与性质%Preparation and characteristics of LY294002-1oaded albumin nanoparticles for intravenous injection

    Institute of Scientific and Technical Information of China (English)

    戴杰; 程亮; 程丽芳; 陈大为; 张文芳

    2013-01-01

    Objective:To develop a new intravenous injection formulation for clinically used anti-cancer agent with the nanoparticles of LY294002 encapsulated into albumin bovine (BSA) (LY294002-BSA-NPs),and to evaluate the physic-chemical and in vitro release properties of LY294002-albumin nanoemulsion.Methods:LY294002-loaded albumin nanoemulsion and the lyophilized nanoparticles were prepared by a high-pressure homogenization NabTM technology and characterized by particle size,Zeta potential,transmission electron microscope (TEM) and X-ray powder diffraction.In vitro release of LY294002-albumin nanoemulsion was investigated by dialysis method.Results:LY294002-BSA-NPs were successfully prepared with following properties:spherical shapes,40 nm size,-45 mV zeta potential and 99% encapsulation efficiency; 81.2% of the drug was sustained to release in 24 hours.Based on XRD,LY294002 was demonstrated to be completely encapsulated within albumin core-shell structure in amorphous state.Conclusion:The nanoemulsion is stable and homogeneous,and the method described to prepare LY294002-albumin nanoemulsion may be possibly applied to develop a new delivery of LY294002 intravenous injection.%目的:研究LY294002白蛋白结合型纳米注射剂的制备工艺,对其理化性质及体外释放进行表征.方法:以NabTM法成功制备LY294002白蛋白纳米乳剂及其冻干制剂,利用纳米粒度仪、透射电子显微镜、X射线粉末衍射仪对其形态、结构表征;透析法研究其体外释放.结果:纳米乳剂颗粒为球形或椭球形,冻干粉复溶后粒径约40 nm,Zeta电位约-45 mV,药物包封率约99%,体外24 h释放81.2%.LY294002以无定形被白蛋白包裹.结论:纳米乳剂性质稳定,制备方法简便,有望成为其新型给药系统.

  12. Microlensing of the Fe K$\\alpha$ line and the X-ray continuum

    CERN Document Server

    Popovic, L C; Mediavilla, E; Zakharov, A F; Abajas, C; Muñoz, J A; Chartas, G

    2005-01-01

    The observed enhancement of the Fe K$\\alpha$ line in three gravitationally lensed QSOs (MG J0414+0534, QSO 2237+0305, H1413+117) is interpreted in terms of microlensing, even when equivalent X-ray continuum amplification is not observed. In order to interpret these observations, first we studied the effects of microlensing on quasars spectra, produced by straight fold caustic crossing over standard relativistic accretion disk. The disk emission was analyzed using the ray tracing method, considering Schwarzschild and Kerr metrics. When the emission is separated in two regions (an inner disk corresponding to the Fe K$\\alpha$ line and an outer annulus corresponding to the continuum, or vice-versa) we find microlensing events which enhance the Fe K$\\alpha$ line without noticeable amplification of the X-ray continuum, but only during a limited time interval. Continuum amplification is expected if a complete microlensing event is monitored. Second, we studied a more realistic case of amplification by caustic magnif...

  13. Phase I study of LY2181308, an antisense oligonucleotide against survivin, in patients with advanced solid tumors.

    Science.gov (United States)

    Tanioka, M; Nokihara, H; Yamamoto, N; Yamada, Y; Yamada, K; Goto, Y; Fujimoto, T; Sekiguchi, R; Uenaka, K; Callies, S; Tamura, T

    2011-08-01

    LY2181308 is an antisense oligonucleotide that complementarily binds to survivin mRNA and inhibits its expression in tumor tissue. This phase I dose escalation study evaluated the tolerability, pharmacokinetics, and anticancer activity of LY2181308 in Japanese. Patients with solid tumors refractory to standard therapy received LY2181308 (400, 600, or 750 mg) as a 3-h intravenous infusion for 3 consecutive days and thereafter once a week. LY2181308 was administered to 14 patients, aged 44-73 (median 60) years. Flu-like syndrome, prolonged prothrombin time-international normalized ratio (PT-INR), thrombocytopenia, and fatigue were common reversible grade 1/2 toxicities. The dose-limiting toxicity was reversible grade 3 elevation of ALT/AST/γ-GTP in 1 patient treated at the 750-mg dose. Pharmacokinetic analysis showed a long terminal half-life of 21 days and an extensive tissue distribution of LY2181308. In 12 evaluable patients, one patient had stable disease, while the remaining 11 patients had progressive disease. LY2181308 monotherapy is well tolerated up to 750 mg with a manageable toxicity, the pharmacokinetic profile warrants further evaluation of LY2181308 in combination with cytotoxic agents or radiotherapy.

  14. Targeting of Ly9 (CD229) Disrupts Marginal Zone and B1 B Cell Homeostasis and Antibody Responses.

    Science.gov (United States)

    Cuenca, Marta; Romero, Xavier; Sintes, Jordi; Terhorst, Cox; Engel, Pablo

    2016-01-15

    Marginal zone (MZ) and B1 B cells have the capacity to respond to foreign Ags more rapidly than conventional B cells, providing early immune responses to blood-borne pathogens. Ly9 (CD229, SLAMF3), a member of the signaling lymphocytic activation molecule family receptors, has been implicated in the development and function of innate T lymphocytes. In this article, we provide evidence that in Ly9-deficient mice splenic transitional 1, MZ, and B1a B cells are markedly expanded, whereas development of B lymphocytes in bone marrow is unaltered. Consistent with an increased number of these B cell subsets, we detected elevated levels of IgG3 natural Abs and a striking increase of T-independent type II Abs after immunization with 2,4,6-trinitrophenyl-Ficoll in the serum of Ly9-deficient mice. The notion that Ly9 could be a negative regulator of innate-like B cell responses was supported by the observation that administering an mAb directed against Ly9 to wild-type mice selectively eliminated splenic MZ B cells and significantly reduced the numbers of B1 and transitional 1 B cells. In addition, Ly9 mAb dramatically diminished in vivo humoral responses and caused a selective downregulation of the CD19/CD21/CD81 complex on B cells and concomitantly an impaired B cell survival and activation in an Fc-independent manner. We conclude that altered signaling caused by the absence of Ly9 or induced by anti-Ly9 may negatively regulate development and function of innate-like B cells by modulating B cell activation thresholds. The results suggest that Ly9 could serve as a novel target for the treatment of B cell-related diseases.

  15. Targeting of Ly9 (CD229) disrupts marginal zone and B1 B cell homeostasis and antibody responses1

    Science.gov (United States)

    Cuenca, Marta; Romero, Xavier; Sintes, Jordi; Terhorst, Cox; Engel, Pablo

    2015-01-01

    Marginal zone and B1 B-cells have the capacity to respond to foreign antigens more rapidly than conventional B-cells, providing early immune responses to blood-borne pathogens. Ly9 (CD229, SLAMF3), a member of the SLAM family receptors, has been implicated in the development and function of innate T lymphocytes. Here, we provide evidence that in Ly9-deficient mice splenic transitional T1, marginal zone and B1a B cells are markedly expanded, whilst development of B lymphocytes in bone marrow is unaltered. Consistent with an increased number of these B cell subsets, we detect elevated levels of IgG3 natural antibodies, and a striking increase of T-independent type II antibodies following immunization with TNP-Ficoll in the serum of Ly9-deficient mice. The notion that Ly9 could be a negative regulator of innate-like B cell responses was supported by the observation that administering a mAb directed against Ly9 to WT mice selectively eliminated splenic marginal zone B cells and significantly reduced the numbers of B1 and transitional T1 B cells. Additionally, Ly9 mAb dramatically diminished in vivo humoral responses and caused a selective down-regulation of the CD19/CD21/CD81 complex on B cells and concomitantly an impaired B cell survival and activation in a Fc-independent manner. We conclude that altered signaling due to the absence of Ly9 or induced by anti-Ly9 may negatively regulate development and function of innate-like B cells by modulating B cell activation thresholds. The results suggest that Ly9 could serve as a novel target for the treatment of B cell related diseases. PMID:26667173

  16. A novel small molecular STAT3 inhibitor, LY5, inhibits cell viability, cell migration, and angiogenesis in medulloblastoma cells.

    Science.gov (United States)

    Xiao, Hui; Bid, Hemant Kumar; Jou, David; Wu, Xiaojuan; Yu, Wenying; Li, Chenglong; Houghton, Peter J; Lin, Jiayuh

    2015-02-06

    Signal transducers and activators of transcription 3 (STAT3) signaling is persistently activated and could contribute to tumorigenesis of medulloblastoma. Numerous studies have demonstrated that inhibition of the persistent STAT3 signaling pathway results in decreased proliferation and increased apoptosis in human cancer cells, indicating that STAT3 is a viable molecular target for cancer therapy. In this study, we investigated a novel non-peptide, cell-permeable small molecule, named LY5, to target STAT3 in medulloblastoma cells. LY5 inhibited persistent STAT3 phosphorylation and induced apoptosis in human medulloblastoma cell lines expressing constitutive STAT3 phosphorylation. The inhibition of STAT3 signaling by LY5 was confirmed by down-regulating the expression of the downstream targets of STAT3, including cyclin D1, bcl-XL, survivin, and micro-RNA-21. LY5 also inhibited the induction of STAT3 phosphorylation by interleukin-6 (IL-6), insulin-like growth factor (IGF)-1, IGF-2, and leukemia inhibitory factor in medulloblastoma cells, but did not inhibit STAT1 and STAT5 phosphorylation stimulated by interferon-γ (IFN-γ) and EGF, respectively. In addition, LY5 blocked the STAT3 nuclear localization induced by IL-6, but did not block STAT1 and STAT5 nuclear translocation mediated by IFN-γ and EGF, respectively. A combination of LY5 with cisplatin or x-ray radiation also showed more potent effects than single treatment alone in the inhibition of cell viability in human medulloblastoma cells. Furthermore, LY5 demonstrated a potent inhibitory activity on cell migration and angiogenesis. Taken together, these findings indicate LY5 inhibits persistent and inducible STAT3 phosphorylation and suggest that LY5 is a promising therapeutic drug candidate for medulloblastoma by inhibiting persistent STAT3 signaling.

  17. 3-D-geocoronal hydrogen density derived from TWINS Ly-α-data

    Directory of Open Access Journals (Sweden)

    J. H. Zoennchen

    2010-06-01

    Full Text Available Based on Ly-α-line-of-sight measurements taken with two Ly-α detectors onboard of the satellite TWINS1 (Two Wide-angle Imaging Neutral-atom Spectrometers density profiles of the exospheric, neutral geocoronal hydrogen were derived for the time period between summer solstice and fall equinox 2008. With the help of specifically developed inversion programs from Ly-α line of sight intensities the three-dimensional density structure of the geocoronal hydrogen at geocentric distances r>3 RE could be derived for the period mentioned characterized by very low solar 10.7 cm radiofluxes of ≈65–70 [10−22 W m−2 Hz−1]. The time-variable, solar "line-centered"-Ly-α-flux was extracted on the basis of daily (terrestrial NGDC 10.7 cm radioflux data using the models from Barth et al. (1990 and Vidal-Madjar (1975.

    The results for the geocoronal H-densities are compared here both with theoretical calculations based on a Monte-Carlo model by Hodges (1994 and with density profiles obtained with the Geocoronal Imager (GEO by Østgaard and Mende (2003. In our results we find a remarkably more pronounced day-/night-side asymmetry which clearly hints to the existence of a hydrogen geotail (i.e. a tail structure with comparatively higher hydrogen densities on the night side of the earth for geocenctric distances >4 RE, and a only weakly pronounced polar depletion. These unexpected features we try to explain by new models in the near future. The derived 3-D-H-density structures are able to explain the line-of-sight (LOS dependent Ly-α intensity variations for all LOS seen up to now with TWINS-LAD. The presented results are valid for the region with geocentric distances 3 RE<r<7 RE and are based on the reasonable assumption of an optically thin H-exosphere with respect to resonant Ly-α-scattering allowing the use of single

  18. Neutral ISM, Lyα, and Lyman-continuum in the Nearby Starburst Haro11

    Science.gov (United States)

    Rivera-Thorsen, T. Emil; Östlin, Göran; Hayes, Matthew; Puschnig, Johannes

    2017-03-01

    Star-forming galaxies are believed to be a major source of Lyman continuum (LyC) radiation responsible for reionizing the early universe. Direct observations of escaping ionizing radiation have however been sparse and with low escape fractions. In the local universe, only 10 emitters have been observed, with typical escape fractions of a few percent. The mechanisms regulating this escape need to be strongly evolving with redshift in order to account for the epoch of reionization. Gas content and star formation feedback are among the main suspects, known to both regulate neutral gas coverage and evolve with cosmic time. In this paper, we reanalyze Hubble Space Telescope (HST)-Cosmic Origins Spectrograph (COS) spectrocopy of the first detected local LyC leaker, Haro 11. We examine the connection between LyC leakage and Lyα line shape, and feedback-influenced neutral interstellar medium (ISM) properties like kinematics and gas distribution. We discuss the two extremes of an optically thin, density bounded ISM and a riddled, optically thick, ionization bounded ISM, and how Haro 11 fits into theoretical predictions. We find that the most likely ISM model is a clumpy neutral medium embedded in a highly ionized medium with a combined covering fraction of unity and a residual neutral gas column density in the ionized medium high enough to be optically thick to Lyα, but low enough to be at least partly transparent to LyC and undetected in Si ii. This suggests that star formation feedback and galaxy-scale interaction events play a major role in opening passageways for ionizing radiation through the neutral medium. Based on observations with HST-COS, program GO 13017, obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and

  19. Updated Models for the Creation of a Low-z QSO Absorber by a Dwarf Galaxy Wind

    CERN Document Server

    Keeney, Brian A; Stocke, John T; Danforth, Charles W; Levesque, Emily M

    2014-01-01

    We present new GALEX images and optical spectroscopy of J1229+02, a dwarf post-starburst galaxy located 81 kpc from the 1585 km/s absorber in the 3C 273 sight line. The absence of H\\alpha\\ emission and the faint GALEX UV fluxes confirm that the galaxy's recent star formation rate is $1$R_{vir}$ are likely intergalactic systems and cannot be identified unambiguously as the circumgalactic material of any one individual galaxy.

  20. Faddeev calculation of 3 alpha and alpha alpha Lambda systems using alpha alpha resonating-group method kernel

    CERN Document Server

    Fujiwara, Y; Kohno, M; Suzuki, Y; Baye, D; Sparenberg, J M

    2004-01-01

    We carry out Faddeev calculations of three-alpha (3 alpha) and two-alpha plus Lambda (alpha alpha Lambda) systems, using two-cluster resonating-group method kernels. The input includes an effective two-nucleon force for the alpha alpha resonating-group method and a new effective Lambda N force for the Lambda alpha interaction. The latter force is a simple two-range Gaussian potential for each spin-singlet and triplet state, generated from the phase-shift behavior of the quark-model hyperon-nucleon interaction, fss2, by using an inversion method based on supersymmetric quantum mechanics. Owing to the exact treatment of the Pauli-forbidden states between the clusters, the present three-cluster Faddeev formalism can describe the mutually related, alpha alpha, 3 alpha and alpha alpha Lambda systems, in terms of a unique set of the baryon-baryon interactions. For the three-range Minnesota force which describes the alpha alpha phase shifts quite accurately, the ground-state and excitation energies of 9Be Lambda are...