WorldWideScience

Sample records for dry major mergers

  1. The coordinated key role of wet, mixed, and dry major mergers in the buildup of massive early-type galaxies at z<~1

    CERN Document Server

    Eliche-Moral, M Carmen; Gallego, Jesus; Zamorano, Jaime

    2010-01-01

    Hierarchical models predict that massive early-type galaxies (mETGs) derive from the most massive and violent merging sequences occurred in the Universe. However, the role of wet, mixed, and dry major mergers in the assembly of mETGs is questioned by some recent observations. We have developed a semi-analytical model to test the feasibility of the major-merger origin hypothesis for mETGs, just accounting for the effects on galaxy evolution of the major mergers strictly reported by observations. The model proves that it is feasible to reproduce the observed number density evolution of mETGs since z~1, just accounting for the coordinated effects of wet/mixed/dry major mergers. It can also reconcile the different assembly redshifts derived by hierarchical models and by mass downsizing data for mETGs, just considering that a mETG observed at a certain redshift is not necessarily in place since then. The model predicts that wet major mergers have controlled the mETGs buildup since z~1, although dry and mixed merge...

  2. DRY MERGER RATE AND POST-MERGER FRACTION IN THE COMA CLUSTER CORE

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Juan P.; Campusano, Luis E.; Haines, Christopher P. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); De Propris, Roberto [Finnish Centre for Astronomy with ESO, University of Turku, Vaisalantie 20, Piikkio, FI-21500 (Finland); Weinzirl, Tim [School of Physics and Astronomy, The University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Jogee, Shardha, E-mail: jcordero@das.uchile.cl [Department of Astronomy, The University of Texas at Austin, Austin, TX 78712-1205 (United States)

    2016-01-20

    We evaluate the dry merger activity in the Coma cluster, using a spectroscopically complete sample of 70 red-sequence (RS) galaxies, most of which (∼75%) are located within 0.2R{sub 200} (∼0.5 Mpc) from the cluster center, with data from the Coma Treasury Survey obtained with the Hubble Space Telescope. The fraction of close galaxy pairs in the sample is the proxy employed for the estimation of the merger activity. We identify 5 pairs and 1 triplet, enclosing a total of 13 galaxies, based on limits on projected separation and line-of-sight velocity difference. Of these systems, none show signs of ongoing interaction, and therefore we do not find any true mergers in our sample. This negative result sets a 1σ upper limit of 1.5% per Gyr for the major dry merger rate, consistent with the low rates expected in present-day clusters. Detailed examination of the images of all the RS galaxies in the sample reveals only one with low surface brightness features identifiable as the remnant of a past merger or interaction, implying a post-merger fraction below 2%.

  3. Dry Merger Rate and Post-merger Fraction in the Coma Cluster Core

    CERN Document Server

    Cordero, Juan P; De Propris, Roberto; Haines, Christopher P; Weinzirl, Tim; Jogee, Shardha

    2016-01-01

    We evaluate the dry merger activity in the Coma cluster, using a spectroscopically complete sample of 70 red-sequence (RS) galaxies, most of which (~75%) are located within 0.2R200 (~0.5 Mpc) from the cluster center, with data from the Coma Treasury Survey obtained with the Hubble Space Telescope. The fraction of close galaxy pairs in the sample is the proxy employed for the estimation of the merger activity. We identify 5 pairs and 1 triplet, enclosing a total of 13 galaxies, based on limits on projected separation and line-of-sight velocity difference. Of these systems, none show signs of ongoing interaction, and therefore we do not find any true mergers in our sample. This negative result sets a 1{\\sigma} upper limit of 1.5% per Gyr for the major dry merger rate, consistent with the low rates expected in present-day clusters. Detailed examination of the images of all the RS galaxies in the sample reveals only one with low surface brightness features identifiable as the remnant of a past merger or interacti...

  4. Creating lenticular galaxies with major mergers

    CERN Document Server

    Querejeta, Miguel; Tapia, Trinidad; Borlaff, Alejandro; van de Ven, Glenn; Lyubenova, Mariya; Martig, Marie; Falcón-Barroso, Jesús; Méndez-Abreu, Jairo; Zamorano, Jaime; Gallego, Jesús

    2016-01-01

    Lenticular galaxies (S0s) represent the majority of early-type galaxies in the local Universe, but their formation channels are still poorly understood. While galaxy mergers are obvious pathways to suppress star formation and increase bulge sizes, the marked parallelism between spiral and lenticular galaxies (e.g. photometric bulge-disc coupling) seemed to rule out a potential merger origin. Here, we summarise our recent work in which we have shown, through N-body numerical simulations, that disc-dominated lenticulars can emerge from major mergers of spiral galaxies, in good agreement with observational photometric scaling relations. Moreover, we show that mergers simultaneously increase the light concentration and reduce the angular momentum relative to their spiral progenitors. This explains the mismatch in angular momentum and concentration between spirals and lenticulars recently revealed by CALIFA observations, which is hard to reconcile with simple fading mechanisms (e.g. ram-pressure stripping).

  5. 2MASS/SDSS Close Major-Merger Galaxy Pairs: Luminosity Functions and Merger Mass Dependence

    CERN Document Server

    Domingue, Donovan L; Jarrett, T H; Cheng, Y

    2009-01-01

    We select a close "major-merger candidate" galaxy pair sample in order to calculate the K_{s} luminosity function (LF) and pair fraction representative of the merger/interaction component of galaxy evolution in the local universe. The pair sample (projected separation 5 h$^{-1}$ kpc $\\leq$ r $\\leq$ 20 h$^{-1}$ kpc, $K_{s}$-band magnitude difference $\\Delta

  6. Major Mergers Going Notts: Challenges for Modern Halo Finders

    CERN Document Server

    Behroozi, Peter; Pearce, Frazer R; Elahi, Pascal; Han, Jiaxin; Lux, Hanni; Mao, Yao-Yuan; Muldrew, Stuart I; Potter, Doug; Srisawat, Chaichalit

    2015-01-01

    Merging haloes with similar masses (i.e., major mergers) pose significant challenges for halo finders. We compare five halo finding algorithms' (AHF, HBT, Rockstar, SubFind, and VELOCIraptor) recovery of halo properties for both isolated and cosmological major mergers. We find that halo positions and velocities are often robust, but mass biases exist for every technique. The algorithms also show strong disagreement in the prevalence and duration of major mergers, especially at high redshifts (z>1). This raises significant uncertainties for theoretical models that require major mergers for, e.g., galaxy morphology changes, size changes, or black hole growth, as well as for finding Bullet Cluster analogues. All finders not using temporal information also show host halo and subhalo relationship swaps over successive timesteps, requiring careful merger tree construction to avoid problematic mass accretion histories. We suggest that future algorithms should combine phase-space and temporal information to avoid the...

  7. The Effect of Dry Mergers on the Color-Magnitude Relation

    Science.gov (United States)

    Skelton, R. E.; Bell, E. F.; Sommerville, R. S.

    2009-12-01

    We investigate the effect of gas-poor (so-called “dry”) mergers on the color-magnitude relation (CMR) of early-type galaxies through a simple toy model and compare with low-z observations from the Sloan Digital Sky Survey (SDSS). The observed red sequence shows a tilt towards bluer colors and a decrease in scatter at the bright end. These characteristics are predicted by our model, based on merger trees from a semi-analytic model of galaxy formation. We assume galaxies move onto a “creation red sequence” when they undergo major gas-rich mergers. Subsequent dry mergers move galaxies along the relation by increasing their mass, but also make them slightly bluer. This occurs because bright galaxies are most likely to merge with one of the more numerous fainter and consequently bluer galaxies that lie further down the relation. Bright galaxies undergo a higher fraction of dry mergers than faint galaxies, which causes a change in the slope of the CMR. A more realistic model that includes scatter in the initial relation shows that dry merging causes a tightening of the CMR towards the bright end. The small scatter in the observed CMR thus cannot be used to argue against significant mass growth from dry merging.

  8. The declining importance of major mergers for galaxy assembly at 1

    CERN Document Server

    Williams, Rik J; Franx, Marijn

    2011-01-01

    Using mass-selected galaxy samples from deep multiwavelength data we investigate the incidence of close galaxy pairs between z=0.4-2. Many such close pairs will eventually merge, and the pair fraction is therefore connected to the merger rate. In this analysis we distinguish between likely progenitors of "dry mergers" (two quiescent red galaxies) and those that include star-forming constituents. Over this redshift range 4-7% of log M/Msun>10.5 quiescent galaxies have a similar-mass quiescent galaxy within 30h^-1 kpc; when minor companions (1:10 mass ratio or greater) are included, the "dry" pair fraction increases to 5-15%. The mean total pair fraction, including both star-forming and quiescent companions to massive "dead" galaxies, is essentially constant (within ~10%) to z=2 for both major and minor merger candidates. If the constant pair fraction to z=2 implies a roughly constant merger rate per unit time, then most mergers in fact occur at z<1. Thus, even though other studies find major mergers to be r...

  9. The Space Density Evolution of Wet and Dry Mergers in the Canada-France-Hawaii Telescope Legacy Survey

    CERN Document Server

    Chou, Richard C Y; Abraham, Roberto G

    2010-01-01

    We analyze 1298 merging galaxies with redshifts up to z=0.7 from the Canada-France-Hawaii Telescope Legacy Survey, taken from the catalog presented in Bridge et al. (2010). By analyzing the internal colors of these systems, we show that so-called wet and dry mergers evolve in different senses, and quantify the space densities of these systems. The local space density of wet mergers is essentially dentical to the local space density of dry mergers. The evolution in the total merger rate is modest out to z ~ 0.7, although the wet and dry populations have different evolutionary trends. At higher redshifts dry mergers make a smaller contribution to the total merging galaxy population, but this is offset by a roughly equivalent increase in the contribution from wet mergers. By comparing the mass density function of early-type galaxies to the corresponding mass density function for merging systems, we show that not all the major mergers with the highest masses (M_stellar > 10^11 M_solar) will end up with the most m...

  10. SHOCKING TAILS IN THE MAJOR MERGER ABELL 2744

    Energy Technology Data Exchange (ETDEWEB)

    Owers, Matt S.; Couch, Warrick J. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, VIC 3122 (Australia); Nulsen, Paul E. J.; Randall, Scott W., E-mail: mowers@aao.gov.au [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2012-05-01

    We identify four rare 'jellyfish' galaxies in Hubble Space Telescope imagery of the major merger cluster Abell 2744. These galaxies harbor trails of star-forming knots and filaments which have formed in situ in gas tails stripped from the parent galaxies, indicating they are in the process of being transformed by the environment. Further evidence for rapid transformation in these galaxies comes from their optical spectra, which reveal starburst, poststarburst, and active galactic nucleus features. Most intriguingly, three of the jellyfish galaxies lie near intracluster medium features associated with a merging 'Bullet-like' subcluster and its shock front detected in Chandra X-ray images. We suggest that the high-pressure merger environment may be responsible for the star formation in the gaseous tails. This provides observational evidence for the rapid transformation of galaxies during the violent core passage phase of a major cluster merger.

  11. Shocking Tails in the Major Merger Abell 2744

    CERN Document Server

    Owers, Matt S; Nulsen, Paul E J; Randall, Scott W

    2012-01-01

    We identify four rare "jellyfish" galaxies in Hubble Space Telescope imagery of the major merger cluster Abell 2744. These galaxies harbor trails of star-forming knots and filaments which have formed in-situ in gas tails stripped from the parent galaxies, indicating they are in the process of being transformed by the environment. Further evidence for rapid transformation in these galaxies comes from their optical spectra, which reveal starburst, poststarburst and AGN features. Most intriguingly, three of the jellyfish galaxies lie near ICM features associated with a merging "Bullet-like" subcluster and its shock front detected in Chandra X-ray images. We suggest that the high pressure merger environment may be responsible for the star formation in the gaseous tails. This provides observational evidence for the rapid transformation of galaxies during the violent core passage phase of a major cluster merger.

  12. High-redshift major mergers weakly enhance star formation

    Science.gov (United States)

    Fensch, J.; Renaud, F.; Bournaud, F.; Duc, P.-A.; Agertz, O.; Amram, P.; Combes, F.; Di Matteo, P.; Elmegreen, B.; Emsellem, E.; Jog, C. J.; Perret, V.; Struck, C.; Teyssier, R.

    2017-02-01

    Galaxy mergers are believed to trigger strong starbursts. This is well assessed by observations in the local Universe. However, the efficiency of this mechanism has poorly been tested so far for high-redshift, actively star-forming, galaxies. We present a suite of pc-resolution hydrodynamical numerical simulations to compare the star formation process along a merging sequence of high- and low-redshift galaxies, by varying the gas mass fraction between the two models. We show that, for the same orbit, high-redshift gas-rich mergers are less efficient than low-redshift ones at producing starbursts; the star formation rate excess induced by the merger and its duration are both around 10 times lower than in the low gas fraction case. The mechanisms that account for the star formation triggering at low redshift - the increased compressive turbulence, gas fragmentation, and central gas inflows - are only mildly, if not at all, enhanced for high gas fraction galaxy encounters. Furthermore, we show that the strong stellar feedback from the initially high star formation rate in high-redshift galaxies does not prevent an increase of the star formation during the merger. Our results are consistent with the observed increase of the number of major mergers with increasing redshift being faster than the respective increase in the number of starburst galaxies.

  13. Could M31 be the result of a major merger?

    Directory of Open Access Journals (Sweden)

    Puech M.

    2012-02-01

    Full Text Available We investigated a scenario in which M31 could be the remnant of a gas-rich major merger. Galaxy merger simulations, highly constrained by observations, were run using GADGET 2 in order to reproduce M31. We succeeded in reproducing the global shape of M31, the thin disk and the bulge, and in addition some of the main M31 large-scale features, such as the thick disk, the 10 kpc ring and the Giant Stream. This lead to a new explanation of the Giant Stream which could be caused by tidal tail stars that have been captured by the galaxy potential.

  14. Galaxy Zoo: Major Galaxy Mergers Are Not a Significant Quenching Pathway

    Science.gov (United States)

    Weigel, Anna K.; Schawinski, Kevin; Caplar, Neven; Carpineti, Alfredo; Hart, Ross E.; Kaviraj, Sugata; Keel, William C.; Kruk, Sandor J.; Lintott, Chris J.; Nichol, Robert C.; Simmons, Brooke D.; Smethurst, Rebecca J.

    2017-08-01

    We use stellar mass functions to study the properties and the significance of quenching through major galaxy mergers. In addition to SDSS DR7 and Galaxy Zoo 1 data, we use samples of visually selected major galaxy mergers and post-merger galaxies. We determine the stellar mass functions of the stages that we would expect major-merger-quenched galaxies to pass through on their way from the blue cloud to the red sequence: (1) major merger, (2) post-merger, (3) blue early type, (4) green early type, and (5) red early type. Based on their similar mass function shapes, we conclude that major mergers are likely to form an evolutionary sequence from star formation to quiescence via quenching. Relative to all blue galaxies, the major-merger fraction increases as a function of stellar mass. Major-merger quenching is inconsistent with the mass and environment quenching model. At z˜ 0, major-merger-quenched galaxies are unlikely to constitute the majority of galaxies that transition through the green valley. Furthermore, between z˜ 0-0.5, major-merger-quenched galaxies account for 1%-5% of all quenched galaxies at a given stellar mass. Major galaxy mergers are therefore not a significant quenching pathway, neither at z˜ 0 nor within the last 5 Gyr. The majority of red galaxies must have been quenched through an alternative quenching mechanism that causes a slow blue to red evolution. .

  15. Dynamical masses and non-homology of massive elliptical galaxies grown by dry mergers

    CERN Document Server

    Frigo, Matteo

    2016-01-01

    We study whether dry merger-driven size growth of massive elliptical galaxies depends on their initial structural concentration, and analyse the validity of the homology hypothesis for virial mass determination in massive ellipticals grown by dry mergers. High-resolution simulations of a few realistic merger trees, starting with compact progenitors of different structural concentrations (S\\'ersic indices n), show that galaxy growth has little dependence on the initial S\\'ersic index (larger n leads to slightly larger size growth), and depends more on other particulars of the merger history. We show that the deposition of accreted matter in the outer parts leads to a systematic and predictable breaking of the homology between remnants and progenitors, which we characterize through the evolution, during the course of the merger history, of virial coefficients K = GM/Re \\sigma^2 associated to the most commonly-used dynamical and stellar mass parameters. The virial coefficient for the luminous mass, K , is about ...

  16. THE MAJOR AND MINOR GALAXY MERGER RATES AT z < 1.5

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    Lotz, Jennifer M. [National Optical Astronomical Observatories, 950 N. Cherry Avenue, Tucson, AZ 85719 (United States); Jonsson, Patrik [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Cox, T. J. [Carnegie Observatories, Pasadena, CA (United States); Croton, Darren [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn (Australia); Primack, Joel R. [Department of Physics, University of California, Santa Cruz, CA (United States); Somerville, Rachel S. [Space Telescope Science Institute, 3700 San Martin Dr., Baltimore, MD 21218 (United States); Stewart, Kyle, E-mail: lotz@stsci.edu [Jet Propulsion Laboratory, Pasadena, CA (United States)

    2011-12-01

    Calculating the galaxy merger rate requires both a census of galaxies identified as merger candidates and a cosmologically averaged 'observability' timescale (T{sub obs}(z)) for identifying galaxy mergers. While many have counted galaxy mergers using a variety of techniques, (T{sub obs}(z)) for these techniques have been poorly constrained. We address this problem by calibrating three merger rate estimators with a suite of hydrodynamic merger simulations and three galaxy formation models. We estimate (T{sub obs}(z)) for (1) close galaxy pairs with a range of projected separations, (2) the morphology indicator G - M{sub 20}, and (3) the morphology indicator asymmetry A. Then, we apply these timescales to the observed merger fractions at z < 1.5 from the recent literature. When our physically motivated timescales are adopted, the observed galaxy merger rates become largely consistent. The remaining differences between the galaxy merger rates are explained by the differences in the ranges of the mass ratio measured by different techniques and differing parent galaxy selection. The major merger rate per unit comoving volume for samples selected with constant number density evolves much more strongly with redshift ({proportional_to}(1 + z){sup +3.0{+-}1.1}) than samples selected with constant stellar mass or passively evolving luminosity ({proportional_to}(1 + z){sup +0.1{+-}0.4}). We calculate the minor merger rate (1:4 major merger rate from close pairs from the 'total' merger rate determined by G - M{sub 20}. The implied minor merger rate is {approx}3 times the major merger rate at z {approx} 0.7 and shows little evolution with redshift.

  17. The Insignificance of Major Mergers in Driving Star Formation at z approximately equal to 2

    Science.gov (United States)

    Kaviraj, S.; Cohen, S.; Windhorst, R. A.; Silk, J.; O'Connell, R. W.; Dopita, M. A.; Dekel, A.; Hathi, N. P.; Straughn, A.; Rutkowski, M.

    2012-01-01

    We study the significance of major mergers in driving star formation in the early Universe, by quantifying the contribution of this process to the total star formation budget in 80 massive (M(*) > 10(exp 10) Solar M) galaxies at z approx = 2. Employing visually-classified morphologies from rest-frame V-band HST imaging, we find that 55(exp +/-14)% of the star formation budget is hosted by non-interacting late-types, with 27(exp +/-18% in major mergers and 18(exp +/- 6)% in spheroids. Given that a system undergoing a major merger continues to experience star formation driven by other processes at this epoch (e.g. cold accretion, minor mergers), approx 27% is a likely upper limit for the major-merger contribution to star formation activity at this epoch. The ratio of the average specific star formation rate in major mergers to that in the non-interacting late-types is approx 2.2:1, suggesting that the typical enhancement of star formation due to major merging is modest and that just under half the star formation in systems experiencing major mergers is unrelated to the merger itself. Taking this into account, we estimate that the actual major-merger contribution to the star formation budget may be as low as approx 15%. While our study does not preclude a major-merger-dominated. era in the very early Universe, if the major-merger contribution to star formation does not evolve significantly into larger look-back times, then this process has a relatively insignificant role in driving stellar mass assembly over cosmic time.

  18. The role of major mergers in the size growth of intermediate-mass spheroids

    CERN Document Server

    Kaviraj, S; Cohen, S; Peirani, S; Windhorst, R A; O'Connell, R W; Silk, J; Dopita, M A; Hathi, N P; Koekemoer, A M; Mei, S; Rutkowski, M; Ryan, R E; Shankar, F

    2014-01-01

    We study of the role of major mergers (mass ratios >1:4) in driving size growth in high-redshift (1 10^10.7 MSun SGs at z<1, then major mergers are also likely to play an important role in the size growth of at least some massive SGs in this mass range.

  19. The insignificance of major mergers in driving star formation at z~2

    CERN Document Server

    Kaviraj, S; Windhorst, R A; Silk, J; O'Connell, R W; Dopita, M A; Dekel, A; Hathi, N P; Straughn, A; Rutkowski, M

    2012-01-01

    We study the significance of major-merger-driven star formation in the early Universe, by quantifying the contribution of this process to the total star formation budget in 80 massive (M* > 10^10 MSun) galaxies at z~2. Employing visually-classified morphologies from rest-frame V-band HST imaging, we find that 55+/-14% of the star formation budget is hosted by non-interacting late-types, with 27+/-8% in major mergers and 18+/-6% in spheroids. Given that a system undergoing a major merger continues to experience star formation driven by other processes at this epoch (e.g. cold accretion, minor mergers), ~27% is an upper limit to the major-merger contribution to star formation activity at this epoch. The ratio of the average specific star formation rate in major mergers to that in the non-interacting late-types is ~2.2:1, suggesting that the enhancement of star formation due to major merging is typically modest, and that just under half the star formation in systems experiencing major mergers is unrelated to the...

  20. Dynamical masses and non-homology of massive elliptical galaxies grown by dry mergers

    Science.gov (United States)

    Frigo, M.; Balcells, M.

    2017-08-01

    We study whether dry merger-driven size growth of massive elliptical galaxies depends on their initial structural concentration, and analyse the validity of the homology hypothesis for virial mass determination in massive ellipticals grown by dry mergers. High-resolution simulations of a few realistic merger trees, starting with compact progenitors of different structural concentrations (Sérsic indices n), show that galaxy growth has little dependence on the initial Sérsic index (larger n leads to slightly larger size growth), and depends more on other particulars of the merger history. We show that the deposition of accreted matter in the outer parts leads to a systematic and predictable breaking of the homology between remnants and progenitors, which we characterize through the evolution, during the course of the merger history, of virial coefficients K≡ G M / R_e σ _e^2 associated with the most commonly used dynamical and stellar mass parameters. The virial coefficient for the luminous mass, K⋆, is ∼50 per cent larger at the start of the merger evolution at z ≈ 2 than in z = 0 remnants. Ignoring virial evolution leads to biased virial mass estimates. We provide K corresponding to a variety of dynamical and stellar mass parameters, and provide recipes for the dynamical determination of galaxy masses. For massive, non-compact ellipticals, the popular expression M = 5 R_e σ _e^2 / G underestimates the dynamical mass within the luminous body by factors of up to 4; it instead provides an approximation to the total stellar mass with smaller uncertainty than current stellar-population models.

  1. Satellite Dwarf Galaxies in a Hierarchical Universe: The Prevalence of Dwarf-Dwarf Major Mergers

    CERN Document Server

    Deason, Alis; Garrison-Kimmel, Shea

    2014-01-01

    Mergers are a common phenomenon in hierarchical structure formation, especially for massive galaxies and clusters, but their importance for dwarf galaxies in the Local Group remains poorly understood. We investigate the frequency of major mergers between dwarf galaxies in the Local Group using the ELVIS suite of cosmological zoom-in dissipationless simulations of Milky Way- and M31-like host halos. We find that ~10% of satellite dwarf galaxies with M_star > 10^6 M_sun that are within the host virial radius experienced a major merger of stellar mass ratio closer than 0.1 since z = 1, with a lower fraction for lower mass dwarf galaxies. Recent merger remnants are biased towards larger radial distance and more recent virial infall times, because most recent mergers occurred shortly before crossing within the virial radius of the host halo. Satellite-satellite mergers also occur within the host halo after virial infall, catalyzed by the large fraction of dwarf galaxies that fell in as part of a group. The merger ...

  2. High-redshift major mergers weakly enhance star formation

    CERN Document Server

    Fensch, J; Bournaud, F; Duc, P -A; Agertz, O; Amram, P; Combes, F; Di Matteo, P; Elmegreen, B; Emsellem, E; Jog, C J; Perret, V; Struck, C; Teyssier, R

    2016-01-01

    Galaxy mergers are believed to trigger strong starbursts. This is well assessed by observations in the local Universe. However the efficiency of this mechanism has poorly been tested so far for high redshift, actively star forming, galaxies. We present a suite of pc-resolution hydrodynamical numerical simulations to compare the star formation process along a merging sequence of high and low z galaxies, by varying the gas mass fraction between the two models. We show that, for the same orbit, high-redshift gas- rich mergers are less efficient than low-redshift ones at producing starbursts: the star formation rate excess induced by the merger and its duration are both around 10 times lower than in the low gas fraction case. The mechanisms that account for the star formation triggering at low redshift - the increased compressive turbulence, gas fragmentation, and central gas inflows - are only mildly, if not at all, enhanced for high gas fraction galaxy encounters. Furthermore, we show that the strong stellar fe...

  3. Robust determination of the major merger fraction at z = 0.6 in Groth Strip

    CERN Document Server

    López-Sanjuan, C; García-Dabó, C E; Prieto, M; Cristóbal-Hornillos, D; Eliche-Moral, M C; Abreu, D; Erwin, P; Guzmán, R

    2009-01-01

    (Abridged) We measure the fraction of galaxies undergoing disk-disk major mergers (f_m) at intermediate redshifts (0.35 = 3.5x10^10 M_Sun is R_m = 1.6x10^-4 Mpc^-3 Gyr^-1. When we compare with previous studies at similar redshifts, we find that the merger rate decreases when mass increases.

  4. The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean

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    Chen, Shu-Hua; Liu, Yi-Chin

    2014-10-27

    A strong, convective African tropical disturbance has a greater chance to develop into a Tropical 23 Depression (TD) if it merges with a shallow, dry vortex (D-vortex) from the north of the African 24 easterly jet (AEJ) after leaving the western coast. Using 11-year reanalysis data we found that the 25 western tip of a vortex strip at northwestern Africa can serve as dry vortices for the D-vortex 26 merger if it shifts southward. Another source of D-vortices is the westward propagating lows 27 along the southern edge of the Saharan air. The D-vortex merger process occurred for 63.5% of 28 tropical cyclones (TCs) or developing systems over the main development region of the Atlantic 29 Ocean, while it occurred for 54% of non-developing systems. TC genesis could be largely 30 controlled by the large-scale environment, but the differences in characteristics of vortices 31 associated with the D-vortex merger between developing and non-developing systems could 32 potentially help determine their destinies; in general, developing systems were dominated by a 33 more intense and moist south vortex, while non-developing systems were dominated by a north 34 vortex which was more intense, drier, and larger in size. Analysis also shows that 74% of intense 35 developing systems were involved with the D-vortex merger process. More attention needs to be 36 paid to the D-vortex merger and the characteristics of those vortices as they can play significant 37 roles or have a strong indication in Atlantic TC genesis.

  5. Creating S0s with Major Mergers: A 3D View

    Directory of Open Access Journals (Sweden)

    Miguel Querejeta

    2015-12-01

    Full Text Available A number of simulators have argued that major mergers can sometimes preserve discs, but the possibility that they could explain the emergence of lenticular galaxies (S0s has been generally neglected. In fact, observations of S0s reveal a strong structural coupling between their bulges and discs, which seems difficult to reconcile with the idea that they come from major mergers. However, in our recent papers we have used N-body simulations of binary mergers to show that, under favourable conditions, discs are first destroyed but soon regrow out of the leftover debris, matching observational photometric scaling relations. Additionally, we have shown how the merger scenario agrees with the recent discovery that S0s and most spirals are not compatible in an angular momentum–concentration plane. This important result from CALIFA constitutes a serious objection to the idea that spirals transform into S0s mainly by fading (e.g., via ram-pressure stripping, as that would not explain the observed simultaneous change in λ Re and concentration, but our simulations of major mergers do explain that mismatch. From such a 3D comparison we conclude that mergers must be a relevant process in the build-up of the current population of S0s.

  6. Hubble Space Telescope Images of Red Mergers: How Dry are They?

    CERN Document Server

    Whitaker, K E

    2008-01-01

    Mergers between red galaxies are observed to be common in the nearby Universe, and are thought to be the dominant mechanism by which massive galaxies grow their mass at late times. These ``dry'' mergers can be readily identified in very deep ground based images, thanks to their extended low surface brightness tidal features. However, ground-based images lack the required resolution to determine the morphologies of the merging galaxies, and to measure the amount of dust and associated gas. We present HST/ACS and WFPC2 observations of a sample of 31 bulge-dominated red-sequence galaxies at z~0.1, comprised of ongoing mergers, merger remnants, and undisturbed galaxies. Nearly all galaxies have early-type morphologies and most are well-fit by r^1/4 law surface brightness profiles. We find that only 10% of the galaxies show evidence for the presence of dust. The amount of cold gas (or its upper limit) is calculated from the mean color-excess, assuming a simple relation between gas mass and dust mass. The gas mass ...

  7. The unorthodox evolution of major merger remnants into star-forming spiral galaxies

    CERN Document Server

    Sparre, Martin

    2016-01-01

    Galaxy mergers are believed to play a key role in transforming star-forming disk galaxies into quenched ellipticals. Most of our theoretical knowledge about such morphological transformations does, however, rely on idealised simulations where processes such as cooling of hot halo gas into the disk and gas accretion in the post-merger phase are not treated in a self-consistent cosmological fashion. In this paper we study the morphological evolution of the stellar components of four major mergers occurring at z=0.5 in cosmological hydrodynamical zoom-simulations. In all simulations the merger reduces the disk mass-fraction, but all galaxies simulated at our highest resolution regrow a significant disk by z=0 (with a disk fraction larger than 24%). For runs with our default physics model, which includes galactic winds from star formation and black hole feedback, none of the merger remnants are quenched, but in a set of simulations with stronger black hole feedback we find that major mergers can indeed quench gal...

  8. Incidence of WISE -selected obscured AGNs in major mergers and interactions from the SDSS

    Science.gov (United States)

    Weston, Madalyn E.; McIntosh, Daniel H.; Brodwin, Mark; Mann, Justin; Cooper, Andrew; McConnell, Adam; Nielsen, Jennifer L.

    2017-02-01

    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z ≤ 0.08) catalogue of visually selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2 × 1010 M⊙, we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4] - [4.6] colours associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fibre spectral diagnostics, we map the [3.4] - [4.6] versus [4.6] - [12] colours of different emission-line galaxies and find that one-quarter of Seyferts have colours indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGNs missed at shorter wavelengths are at the heart of the ongoing AGN-merger connection debate. The vast majority of mergers hosting dusty AGNs are star forming and located at the centres of Mhalo < 1013 M⊙ groups. Assuming plausibly short-duration dusty-AGN phases, we speculate that a large fraction of gas-rich mergers experience a brief obscured AGN phase, in agreement with the strong connection between central star formation and black hole growth seen in merger simulations.

  9. The pair and major merger history of galaxies up to z=6 over 3 square degrees

    Science.gov (United States)

    Conselice, Christopher; Mundy, Carl; Duncan, Kenneth

    2017-01-01

    A major goal in extragalactic astronomy is understanding how stars and gas are put into galaxies. As such we present the pair fraction and derived major merger and stellar mass assembly histories of galaxies up to z = 6. We do this using new techniques from photometric redshift probability distribution functions, and state of the art deep near-infrared data from the UDS, VIDEO and UltraVISTA COSMOS fields for galaxies at z 1 there must be a very important unknown mode of baryonic acquisition within galaxies that is not associated with major mergers. We further discuss how the merger history stays relatively constant at higher redshifts, and show the comparison of our results to theoretical predictions.

  10. Evolution of the major merger galaxy pair fraction at z < 1

    Energy Technology Data Exchange (ETDEWEB)

    Keenan, R. C.; Hsieh, B. C.; Lin, L.; Chou, R. C. Y.; Huang, S.; Lin, J. H.; Chang, K. H. [Academia Sinica Institute for Astronomy and Astrophysics, Taipei, Taiwan (China); Foucaud, S. [Shanghai Jiao Tong University, Shanghai (China); De Propris, R. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Turku (Finland)

    2014-11-10

    We present a study of the largest available sample of near-infrared selected (i.e., stellar mass selected) dynamically close pairs of galaxies at low redshifts (z < 0.3). We combine this sample with new estimates of the major merger pair fraction for stellar mass selected galaxies at z < 0.8, from the Red Sequence Cluster Survey (RCS1). We construct our low-redshift K-band selected sample using photometry from the UKIRT Infrared Deep Sky Survey and the Two Micron All Sky Survey (2MASS) in the K band (∼2.2 μm). Combined with all available spectroscopy, our K-band selected sample contains ∼250, 000 galaxies and is >90% spectroscopically complete. The depth and large volume of this sample allow us to investigate the low-redshift pair fraction and merger rate of galaxies over a wide range in K-band luminosity. We find the major merger pair fraction to be flat at ∼2% as a function of K-band luminosity for galaxies in the range 10{sup 8}-10{sup 12} L {sub ☉}, in contrast to recent results from studies in the local group that find a substantially higher low-mass pair fraction. This low-redshift major merger pair fraction is ∼40%-50% higher than previous estimates drawn from K-band samples, which were based on 2MASS photometry alone. Combining with the RCS1 sample, we find a much flatter evolution (m = 0.7 ± 0.1) in the relation f {sub pair}∝(1 + z) {sup m} than indicated in many previous studies. These results indicate that a typical L ∼ L* galaxy has undergone ∼0.2-0.8 major mergers since z = 1 (depending on the assumptions of merger timescale and percentage of pairs that actually merge).

  11. A consistent measure of the merger histories of massive galaxies using close-pair statistics - I. Major mergers at z < 3.5

    Science.gov (United States)

    Mundy, Carl J.; Conselice, Christopher J.; Duncan, Kenneth J.; Almaini, Omar; Häußler, Boris; Hartley, William G.

    2017-09-01

    We use a large sample of ∼350 000 galaxies constructed by combining the UKIDSS UDS, VIDEO/CFHT-LS, UltraVISTA/COSMOS and GAMA survey regions to probe the major (1:4 stellar mass ratio) merging histories of massive galaxies (>1010 M⊙) at 0.005 probability distributions, to measure pair fractions of flux-limited, stellar mass selected galaxy samples using close-pair statistics. The pair fraction is found to weakly evolve as ∝ (1 + z)0.8 with no dependence on stellar mass. We subsequently derive major merger rates for galaxies at >1010 M⊙ and at a constant number density of n > 10-4 Mpc-3, and find rates a factor of 2-3 smaller than previous works, although this depends strongly on the assumed merger time-scale and likelihood of a close-pair merging. Galaxies undergo approximately 0.5 major mergers at z 1011 M⊙) galaxies have experienced a steady supply of stellar mass via major mergers throughout their evolution. While pair fractions are found to agree with those predicted by the Henriques et al. semi-analytic model, the Illustris hydrodynamical simulation fails to quantitatively reproduce derived merger rates. Furthermore, we find that major mergers become a comparable source of stellar mass growth compared to star formation at z < 1, but is 10-100 times smaller than the star formation rate density at higher redshifts.

  12. Evolution induced by dry minor mergers on to Fast Rotator S0 galaxies

    CERN Document Server

    Tapia, Trinidad; Querejeta, Miguel; Balcells, Marc; González-Garc'\\ia, A César; Prieto, Mercedes; Aguerri, J Alfonso L; Gallego, Jesús; Zamorano, Jaime; Rodríguez-Pérez, Cristina; Borlaff, Alejandro; .,

    2014-01-01

    We have analysed collisionless N-body simulations of intermediate and minor dry mergers on to S0s to test whether these mergers can generate S0 galaxies with intermediate kinematics between Fast and Slow Rotators. We find that minor mergers induce a lower decrease of the global rotational support than encounters of lower mass ratios, giving rise to S0s with intermediate properties between Fast and Slow Rotators. The resulting remnants are intrinsically more triaxial, less flattened, and span the whole range of apparent ellipticities up to $\\epsilon_\\mathrm{e} \\sim 0.8$. They do not show lower apparent ellipticities in random projections than initially; on the contrary, the formation of oval distortions and the disc thickening raise the percentage of projections at $0.4 0.9$), but exhibit a wide range of triaxialities ($0.20 < T < 1.00$). In the plane of global anisotropy of velocities ($\\delta$) vs. intrinsic ellipticity ($\\epsilon_\\mathrm{e,intr}$), some of our models extend the linear trend found in ...

  13. Toward the Distribution of Orbital Parameters of Nearby Major Galaxy Mergers

    Science.gov (United States)

    Mortazavi Karvani, Seyed Alireza

    2016-01-01

    In this thesis project our goal is to measure the initial conditions of a sample of ~20 local disk-disk major galaxy mergers. Measuring the orbital parameters is possible by findingthe most similar galaxy merger simulation to the morphology and kinematics of the data.We have developed an automated modeling method based on the Identikit software package,which also estimates the uncertainty of the measured initial conditions. We tested our modeling method using an independent set of GADGET simulations, and we acquired reliable results onprograde merger systems. We observed the Hα kinematics of our sample using SparsePak IFU on the WIYN telescope at KPNO, and DIS on the 3.5m telescope at APO. For the few merger systems in our sample with archival HI data available, we compare the use of HI vs Hα as the kinematic tracer. This work lays the ground-work for the analysis of larger statistical samples of mergers from on-going IFU galaxy survey such as MaNGA.

  14. Spin Flips - II. Evolution of dark matter halo spin orientation, and its correlation with major mergers

    CERN Document Server

    Bett, Philip E

    2015-01-01

    We expand our previous study on the relationship between changes in the orientation of the angular momentum vector of dark matter haloes ("spin flips") and changes in their mass (Bett & Frenk 2012), to cover the full range of halo masses in a simulation cube of length 100 $h^{-1}$ Mpc. Since strong disturbances to a halo (such as might be indicated by a large change in the spin direction) are likely also to disturb the galaxy evolving within, spin flips could be a mechanism for galaxy morphological transformation without involving major mergers. We find that 35% of haloes have, at some point in their lifetimes, had a spin flip of at least $45\\deg$ that does not coincide with a major merger. Over 75% of large spin flips coincide with non-major mergers; only a quarter coincide with major mergers. We find a similar picture for changes to the inner-halo spin orientation, although here there is an increased likelihood of a flip occurring. Changes in halo angular momentum orientation, and other such measures of...

  15. Zooming in on major mergers: dense, starbursting gas in cosmological simulations

    Science.gov (United States)

    Sparre, Martin; Springel, Volker

    2016-11-01

    We introduce the `Illustris zoom simulation project', which allows the study of selected galaxies forming in the Λcold dark matter (ΛCDM) cosmology with a 40 times better mass resolution than in the parent large-scale hydrodynamical Illustris simulation. We here focus on the starburst properties of the gas in four cosmological simulations of major mergers. The galaxies in our high-resolution zoom runs exhibit a bursty mode of star formation with gas consumption time-scales 10 times shorter than for the normal star formation mode. The strong bursts are only present in the simulations with the highest resolution, hinting that a too low resolution is the reason why the original Illustris simulation showed a dearth of starburst galaxies. Very pronounced bursts of star formation occur in two out of four major mergers we study. The high star formation rates, the short gas consumption time-scales and the morphology of these systems strongly resemble observed nuclear starbursts. This is the first time that a sample of major mergers is studied through self-consistent cosmological hydrodynamical simulations instead of using isolated galaxy models setup on a collision course. We also study the orbits of the colliding galaxies and find that the starbursting gas preferentially appears in head-on mergers with very high collision velocities. Encounters with large impact parameters do typically not lead to the formation of starbursting gas.

  16. Using Galaxy Pairs to Probe Star Formation During Major Halo Mergers

    CERN Document Server

    Behroozi, Peter S; Ferguson, Henry C; Hearin, Andrew P; Lotz, Jennifer; Silk, Joseph; Kassin, Susan; Lu, Yu; Croton, Darren; Somerville, Rachel S; Watson, Douglas F

    2015-01-01

    Currently-proposed galaxy quenching mechanisms predict very different behaviours during major halo mergers, ranging from significant quenching enhancement (e.g., clump-induced gravitational heating models) to significant star formation enhancement (e.g., gas starvation models). To test real galaxies' behaviour, we present an observational galaxy pair method for selecting galaxies whose host haloes are preferentially undergoing major mergers. Applying the method to central L* (10^10 Msun < M* < 10^10.5 Msun) galaxies in the Sloan Digital Sky Survey (SDSS) at z<0.06, we find that major halo mergers can at most modestly reduce the star-forming fraction, from 59% to 47%. Consistent with past research, however, mergers accompany enhanced specific star formation rates for star-forming L* centrals: ~10% when a paired galaxy is within 200 kpc (approximately the host halo's virial radius), climbing to ~70% when a paired galaxy is within 30 kpc. No evidence is seen for even extremely close pairs (<30 kpc se...

  17. The close pair fraction of BCGs since z = 0.5: major mergers dominate recent BCG stellar mass growth

    Science.gov (United States)

    Groenewald, Danièl N.; Skelton, Rosalind E.; Gilbank, David G.; Loubser, S. Ilani

    2017-06-01

    Using the redMaPPer (red-sequence Matched-filter Probabilistic Percolation) cluster catalogue based on the Sloan Digital Sky Survey (SDSS) photometry, we investigate the importance of major mergers in the stellar mass build-up of brightest cluster galaxies (BCGs) between 0.08 ≤ z ≤ 0.50. We use the SDSS spectroscopy, supplemented with spectroscopic observations from the Southern African Large Telescope at higher redshifts, to identify which BCGs and nearby companions are potential major merger candidates. We use the pair fraction as a proxy for the merger fraction in order to determine how much stellar mass growth the BCGs have experienced due to major mergers. We observe a weak trend of the BCG pair fraction increasing with decreasing redshift, suggesting that major mergers may become more important towards the present day. Major mergers are found to contribute, on average, 24 ± 14 (29 ± 17) per cent towards the stellar mass of a present-day BCG since z = 0.32 (0.45), assuming that half of the companion's stellar mass is accreted on to the BCG. Furthermore, using our merger results in conjunction with predictions from two recent semi-analytical models along with observational measurements from the literature, we find that major mergers have sufficient stellar material to account for the stellar mass growth of the intracluster light between z = 0.3 and 0.

  18. Creating S0s with major mergers: a 3D view

    CERN Document Server

    Querejeta, Miguel; Tapia, Trinidad; Borlaff, Alejandro; van de Ven, Glenn; Lyubenova, Mariya; Martig, Marie; Falcón-Barroso, Jesús; Méndez-Abreu, Jairo; Zamorano, Jaime; Gallego, Jesús

    2015-01-01

    A number of simulators have argued that major mergers can sometimes preserve discs (e.g. Springel & Hernquist 2005), but the possibility that they could explain the emergence of lenticular galaxies (S0s) has been generally neglected. In fact, observations of S0s reveal a strong structural coupling between their bulges and discs, which seems difficult to reconcile with the idea that they come from major mergers. However, in Querejeta et al. (2015a) we have used N-body simulations of binary mergers to show that, under favourable conditions, discs are first destroyed but soon regrow out of the leftover debris, matching observational photometric scaling relations (e.g. Laurikainen et al. 2010). Additionally, in Querejeta et al. (2015b) we have shown how the merger scenario agrees with the recent discovery that S0s and most spirals are not compatible in an angular momentum--concentration plane. This important result from CALIFA constitutes a serious objection to the idea that spirals transform into S0s mainly ...

  19. Do the Most Massive Black Holes at z = 2 Grow via Major Mergers?

    Science.gov (United States)

    Mechtley, M.; Jahnke, K.; Windhorst, R. A.; Andrae, R.; Cisternas, M.; Cohen, S. H.; Hewlett, T.; Koekemoer, A. M.; Schramm, M.; Schulze, A.; Silverman, J. D.; Villforth, C.; van der Wel, A.; Wisotzki, L.

    2016-10-01

    The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei (AGN) are primarily triggered during major mergers between gas-rich galaxies. While plausible for decades, this model has only begun to be tested with statistical rigor in the past few years. Here, we report on a Hubble Space Telescope study to test this hypothesis for z = 2 quasars with high supermassive black hole masses ({M}{BH}={10}9{--}{10}10 {M}⊙ ), which dominate cosmic black hole growth at this redshift. We compare Wide Field Camera 3 F160W (rest-frame V-band) imaging of 19 point source-subtracted quasar hosts to a matched sample of 84 inactive galaxies, testing whether the quasar hosts have greater evidence for strong gravitational interactions. Using an expert ranking procedure, we find that the quasar hosts are uniformly distributed within the merger sequence of inactive galaxies, with no preference for quasars in high-distortion hosts. Using a merger/non-merger cutoff approach, we recover distortion fractions of {f}{{m},{qso}}=0.39+/- 0.11 for quasar hosts and {f}{{m},{gal}}=0.30+/- 0.05 for inactive galaxies (distribution modes, 68% confidence intervals), with both measurements subjected to the same observational conditions and limitations. The slight enhancement in distorted fraction for quasar hosts over inactive galaxies is not significant, with a probability that the quasar fraction is higher P({f}{{m},{qso}}\\gt {f}{{m},{gal}})=0.78 (0.78σ ), in line with results for lower mass and lower z AGN. We find no evidence that major mergers are the primary triggering mechanism for the massive quasars that dominate accretion at the peak of cosmic quasar activity.

  20. The role of major mergers in (obscured) black hole growth and galaxy evolution

    Science.gov (United States)

    Treister, E.; Privon, G.; Ricci, C.; Bauer, F.; Schawinski, K.; MODA Collaboration

    2017-10-01

    A clear picture is emerging in which rapid supermassive black hole (SMBH) growth episodes (luminous AGN) are directly linked to major galaxy mergers. Here, we present the first results from our MODA program aimed to obtain optical and near-IR Integral Field Unit (IFU) spectroscopy and mm/sub-mm ALMA maps for a sample of confirmed nearby dual AGN (separation 10 kpc), including the archetypical galaxy NGC6240. Specifically, we will focus here on Mrk 463, a very rich system of two galaxies separated by 3.8 kpc hosting two SMBH growing simultaneously. Clear evidence for complex morphologies and kinematics, outflows and feedback effects can be seen in this system, evidencing the deep connection between major galaxy mergers, SMBH growth and galaxy evolution.

  1. Major mergers are not significant drivers of star formation or morphological transformation around the epoch of peak cosmic star formation

    Science.gov (United States)

    Lofthouse, E. K.; Kaviraj, S.; Conselice, C. J.; Mortlock, A.; Hartley, W.

    2017-03-01

    We investigate the contribution of major mergers (mass ratios >1: 5) to stellar mass growth and morphological transformations around the epoch of peak cosmic star formation (z ∼ 2). We visually classify a complete sample of massive (M > 1010M⊙) galaxies at this epoch, drawn from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, into late-type galaxies, major mergers, spheroids and disturbed spheroids which show morphological disturbances. Given recent simulation work, which indicates that recent (clear tidal features in such images, we use the fraction of disturbed spheroids to probe the role of major mergers in driving morphological transformations. The percentage of blue spheroids (i.e. with ongoing star formation) that show morphological disturbances is only 21 ± 4 per cent, indicating that major mergers are not the dominant mechanism for spheroid creation at z ∼ 2 - other processes, such as minor mergers or cold accretion are likely to be the main drivers of this process. We also use the rest-frame U-band luminosity as a proxy for star formation to show that only a small fraction of the star formation budget (∼3 per cent) is triggered by major mergers. Taken together, our results show that major mergers are not significant drivers of galaxy evolution at z ∼ 2.

  2. A study of major mergers using a multi-phase ISM code

    CERN Document Server

    Weniger, J; Harfst, S

    2009-01-01

    Galaxy interactions are a common phenomenon in clusters of galaxies. Especially major mergers are of particular importance, because they can change the morphological type of galaxies. They have an impact on the mass function of galaxies and they trigger star formation - the main driver of the Galactic Matter Cycle. Therefore, we conducted a study of major mergers by means of a multi-phase ISM code. This code is based on a TREE-SPH-code combined with a sticky particle method allowing for star formation controlled by the properties of a multi-phase ISM. This is in contrast to the usually implemented Schmidt law depending mainly on the gas density. Previously, this code was used on isolated galaxies. Since our star formation recipe is not restricted to a special type of galaxy, it is interesting to apply it to interacting galaxies, too. Our study on major mergers includes a research of global properties of the interacting system, namely the star formation rate and the star formation efficiency, the evaporation a...

  3. Incidence of WISE-Selected Obscured AGNs in Major Mergers and Interactions from the SDSS

    CERN Document Server

    Weston, Madalyn E; Brodwin, Mark; Mann, Justin; Cooper, Andrew; McConnell, Adam; Nielsen, Jennifer L

    2016-01-01

    We use the Wide-field Infrared Survey Explorer (WISE) and the Sloan Digital Sky Survey (SDSS) to confirm a connection between dust-obscured active galactic nuclei (AGNs) and galaxy merging. Using a new, volume-limited (z <= 0.08) catalog of visually-selected major mergers and galaxy-galaxy interactions from the SDSS, with stellar masses above 2x10^10 Msun, we find that major mergers (interactions) are 5-17 (3-5) times more likely to have red [3.4]-[4.6] colors associated with dust-obscured or `dusty' AGNs, compared to non-merging galaxies with similar masses. Using published fiber spectral diagnostics, we map the [3.4]-[4.6] versus [4.6]-[12] colors of different emission-line galaxies and find one-quarter of Seyferts have colors indicative of a dusty AGN. We find that AGNs are five times more likely to be obscured when hosted by a merging galaxy, half of AGNs hosted by a merger are dusty, and we find no enhanced frequency of optical AGNs in merging over non-merging galaxies. We conclude that undetected AGN...

  4. The Effect of Major Mergers on Age and Metallicity Across the Fundamental Plane

    CERN Document Server

    Porter, L A; Croton, D J; Covington, M D; Graves, G J; Faber, S M; Primack, J R

    2012-01-01

    Recent low-redshift observations have attempted to determine the star formation histories of elliptical galaxies by tracking correlations between the stellar population parameters (age and metallicity) and the structural parameters that enter the fundamental plane (size and velocity dispersion). These studies have found that velocity dispersion, rather than effective radius or dynamical mass, is the main predictor of a galaxy's stellar age and metallicity. In this work, we apply an analytic model that predicts the structural properties of remnants formed in major mergers to progenitor disk galaxies with properties taken from two different semi-analytic models. We predict the effective radius, velocity dispersion, luminosity, age, and metallicity of the merger remnants, enabling us to compare directly to observations of early-type galaxies. While we find a tight correlation between age and velocity dispersion, we find a stronger dependence of age and metallicity on effective radius than observations report. Th...

  5. Binary Active Galactic Nuclei in Stripe 82: Constraints on Synchronized Black Hole Accretion in Major Mergers

    CERN Document Server

    Fu, Hai; Myers, A D; Djorgovski, S G; Yan, Lin

    2015-01-01

    Representing simultaneous black hole accretion during a merger, binary active galactic nuclei (AGNs) could provide valuable observational constraints to models of galaxy mergers and AGN triggering. High-resolution radio interferometer imaging offers a promising method to identify a large and uniform sample of binary AGNs, because it probes a generic feature of nuclear activity and is free from dust obscuration. Our previous search yielded 52 strong candidates of kpc-scale binaries over the 92 deg^2 of the Sloan Digital Sky Survey (SDSS) Stripe 82 area with 2"-resolution Very Large Array (VLA) images. Here we present 0.3"-resolution VLA 6 GHz observations for six candidates that have complete optical spectroscopy. The new data confirm the binary nature of four candidates and identify the other two as line-of-sight projections of radio structures from single AGNs. The four binary AGNs at z ~ 0.1 reside in major mergers with projected separations of 4.2-12 kpc. Optical spectral modeling shows that their hosts ha...

  6. Major mergers are not significant drivers of star formation or morphological transformation around the epoch of peak cosmic star formation

    CERN Document Server

    Lofthouse, E K; Conselice, C J; Mortlock, A; Hartley, W

    2016-01-01

    We investigate the contribution of major mergers (mass ratios $>1:5$) to stellar mass growth and morphological transformations around the epoch of peak cosmic star formation ($z\\sim2$). We visually classify a complete sample of massive (M $>$ 10$^{10}$M$_{\\odot}$) galaxies at this epoch, drawn from the CANDELS survey, into late-type galaxies, major mergers, spheroids and disturbed spheroids which show morphological disturbances. Given recent simulation work, which indicates that recent ($<$0.3-0.4 Gyr) major-merger remnants exhibit clear tidal features in such images, we use the fraction of disturbed spheroids to probe the role of major mergers in driving morphological transformations. The percentage of blue spheroids (i.e. with ongoing star formation) that show morphological disturbances is only 21 $\\pm$ 4%, indicating that major mergers are not the dominant mechanism for spheroid creation at $z\\sim2$ - other processes, such as minor mergers or cold accretion are likely to be the main drivers of this proc...

  7. The redshift evolution of major merger triggering of luminous AGNs: a slight enhancement at z ˜ 2

    Science.gov (United States)

    Hewlett, Timothy; Villforth, Carolin; Wild, Vivienne; Mendez-Abreu, Jairo; Pawlik, Milena; Rowlands, Kate

    2017-09-01

    Active galactic nuclei (AGNs), particularly the most luminous AGNs, are commonly assumed to be triggered through major mergers; however, observational evidence for this scenario is mixed. To investigate any influence of galaxy mergers on AGN triggering and luminosities through cosmic time, we present a sample of 106 luminous X-ray-selected type 1 AGNs from the COSMOS survey. These AGNs occupy a large redshift range (0.5 confidence level (∼2.4σ) from visual inspection. Since only ∼15 per cent of these AGNs are found to be in morphologically disturbed galaxies, it is implied that major mergers at high redshift make a noticeable but subdominant contribution to AGN fuelling. At low redshifts, other processes dominate and mergers become a less significant triggering mechanism.

  8. Driving the Growth of the Earliest Supermassive Black Holes with Major Mergers of Host Galaxies

    CERN Document Server

    Tanaka, Takamitsu L

    2014-01-01

    The formation mechanism of supermassive black holes (SMBHs) in general, and of $\\sim 10^9\\,{\\rm M}_{\\odot}$ SMBHs observed as luminous quasars at redshifts $z> 6$ in particular, remains an open fundamental question. The presence of such massive BHs at such early times, when the Universe was less than a billion years old, implies that they grew via either super-Eddington accretion, or nearly uninterrupted gas accretion near the Eddington limit; the latter, at first glance, is at odds with empirical trends at lower redshifts, where quasar episodes associated with rapid BH growth are rare and brief. In this work, I examine whether and to what extent the growth of the $z> 6$ quasar SMBHs can be explained within the standard quasar paradigm, in which major mergers of host galaxies trigger episodes of rapid gas accretion below or near the Eddington limit. Using a suite of Monte Carlo merger tree simulations of the assembly histories of the likely hosts of the $z> 6$ quasars, I investigate (i) their growth and major...

  9. Do the Most Massive Black Holes at $z=2$ Grow via Major Mergers?

    CERN Document Server

    Mechtley, M; Windhorst, R A; Andrae, R; Cisternas, M; Cohen, S H; Hewlett, T; Koekemoer, A M; Schramm, M; Schulze, A; Silverman, J D; Villforth, C; van der Wel, A; Wisotzki, L

    2015-01-01

    The most frequently proposed model for the origin of quasars holds that the high accretion rates seen in luminous active galactic nuclei are primarily triggered during major mergers between gas-rich galaxies. While plausible for decades, this model has only begun to be tested with statistical rigor in the past few years. Here we report on a Hubble Space Telescope study to test the merger-triggering hypothesis for $z=2$ quasars with high super-massive black hole masses ($M_\\mathrm{BH}=10^9-10^{10}~M_\\odot{}$), which dominate cosmic black hole growth at this redshift. We compare Wide Field Camera 3 $F160W$ (rest-frame $V$-band) imaging of 19 point source-subtracted quasar hosts to a matched sample of 84 inactive galaxies, testing whether the quasar hosts have a statistically higher fraction of strong gravitational interaction signatures. We recover strong distortion fractions of $f_\\mathrm{m,qso}=0.39\\pm{}0.11$ for the quasar hosts and $f_\\mathrm{m,gal}=0.30\\pm{}0.05$ for the inactive galaxies (distribution mod...

  10. The VIMOS VLT Deep Survey :Evolution of the major merger rate since z~1 from spectroscopicaly confirmed galaxy pairs

    CERN Document Server

    de Ravel, L; Tresse, L; Bottini, D; Garilli, B; Le Brun, V; MacCagni, D; Scaramella, R; Scodeggio, M; Vettolani, G; Zanichelli, A; Adami, C; Arnouts, S; Bardelli, S; Bolzonella, M; Cappi, A; Charlot, S; Ciliegi, P; Contini, T; Foucaud, S; Franzetti, P; Gavignaud, I; Guzzo, L; Ilbert, O; Iovino, A; Lamareille, F; McCracken, H J; Marano, B; Marinoni, C; Mazure, A; Meneux, B; Merighi, R; Paltani, S; Pellò, R; Pollo, A; Pozzetti, L; Radovich, M; Vergani, D; Zamorani, G; Zucca, E; Bondi, M; Bongiorno, A; Brinchmann, J; Cucciati, O; De la Torre, S; Gregorini, L; Memeo, P; Pérez-Montero, E; Mellier, Y; Merluzzi, P; Temporin, S

    2008-01-01

    From the VIMOS VLT Deep Survey we use a sample of 6447 galaxies with I_{AB} 9.5 has been accreted through major merging events since z ~ 1, indicating that major mergers have contributed significantly to the growth in stellar mass density of bright galaxies over the last half of the life of the Universe.

  11. Where do Wet, Dry, and Mixed Galaxy Mergers Occur? A Study of the Environments of Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey

    CERN Document Server

    Lin, Lihwai; Jian, Hung-Yu; Koo, David C; Patton, David R; Yan, Renbin; Willmer, Christopher N A; Coil, Alison L; Chiueh, Tzihong; Croton, Darren J; Gerke, Brian F; Lotz, Jennifer; Guhathakurta, Puragra; Newman, Jeffrey A

    2010-01-01

    We study the environment of wet, dry, and mixed galaxy mergers at 0.75 < z < 1.2 using close pairs in the DEEP2 Galaxy Redshift Survey. We find that the typical environment of mixed and dry merger candidates is denser than that of wet mergers, mostly due to the color-density relation. While the galaxy companion rate (Nc) is observed to increase with overdensity, using N-body simulations we find that the fraction of pairs that will eventually merge decreases with the local density, predominantly because interlopers are more common in dense environments. After taking into account the merger probability of pairs as a function of local density, we find only marginal environment dependence of the fractional merger rate for wet mergers over the redshift range we have probed. On the other hand, the fractional dry merger rate increases rapidly with local density due to the increased population of red galaxies in dense environments. We also find that the environment distribution of K+A galaxies is similar to tha...

  12. The importance of major mergers in the build up of stellar mass in brightest cluster galaxies at z=1

    CERN Document Server

    Lidman, C; Bauer, A E; Barrientos, L F; Cerulo, P; Couch, W J; Delaye, L; Demarco, R; Ellingson, E; Faloon, A J; Gilbank, D; Huertas-Company, M; Mei, S; Meyers, J; Muzzin, A; Noble, A; Nantais, J; Rettura, A; Rosati, P; Sanchez-Janssen, R; Strazzullo, V; Webb, T M A; Wilson, G; Yan, R; Yee, H K C

    2013-01-01

    Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) have increased their stellar mass by a factor of almost two between z~0.9 and z~0.2. The numerical simulations further suggest that more than half this mass is accreted through major mergers. Using a sample of 18 distant galaxy clusters with over 600 spectroscopically confirmed cluster members between them, we search for observational evidence that major mergers do play a significant role. We find a major merger rate of 0.38 +/- 0.14 mergers per Gyr at z~1. While the uncertainties, which stem from the small size of our sample, are relatively large, our rate is consistent with the results that are derived from numerical simulations. If we assume that this rate continues to the present day and that half of the mass of the companion is accreted onto the BCG during these mergers, then we find that this rate can explain the growth in the stellar mass of the BCGs that is observed and predicted by...

  13. The Major and Minor Galaxy Merger Rates at z < 1.5

    CERN Document Server

    Lotz, Jennifer M; Cox, T J; Croton, Darren; Primack, Joel R; Somerville, Rachel S; Stewart, Kyle

    2011-01-01

    Calculating the galaxy merger rate requires both a census of galaxies identified as merger candidates, and a cosmologically-averaged `observability' timescale T_obs(z) for identifying galaxy mergers. While many have counted galaxy mergers using a variety of techniques, T_obs(z) for these techniques have been poorly constrained. We address this problem by calibrating three merger rate estimators with a suite of hydrodynamic merger simulations and three galaxy formation models. We estimate T_obs(z) for (1) close galaxy pairs with a range of projected separations, (2) the morphology indicator G-M20, and (3) the morphology indicator asymmetry A. Then we apply these timescales to the observed merger fractions at z < 1.5 from the recent literature. When our physically-motivated timescales are adopted, the observed galaxy merger rates become largely consistent. The remaining differences between the galaxy merger rates are explained by the differences in the range of mass-ratio measured by different techniques and...

  14. Evolution along the sequence of S0 Hubble types induced by dry minor mergers. II - Bulge-disk coupling in the photometric relations through merger-induced internal secular evolution

    CERN Document Server

    Eliche-Moral, M Carmen; Aguerri, J Alfonso L; Gallego, Jesus; Zamorano, Jaime; Balcells, Marc; Prieto, Mercedes

    2013-01-01

    Galaxy mergers are considered as questionable mechanisms for the evolution of lenticular galaxies (S0's), on the basis that even minor ones induce structural changes that are difficult to reconcile with the strong bulge-disk coupling observed in the photometric scaling relations of S0's. We check if the evolution induced onto S0's by dry intermediate and minor mergers can reproduce their photometric scaling relations, analysing the bulge-disk decompositions of the merger simulations presented in Eliche-Moral et al. (2012). The mergers induce an evolution in the photometric planes compatible with the data of S0's, even in those ones indicating a strong bulge-disk coupling. The mergers drive the formation of the observed photometric relation in some cases, whereas they induce a slight dispersion compatible with data in others. Therefore, this evolutionary mechanism tends to preserve these scaling relations. In those photometric planes where the morphological types segregate, the mergers always induce evolution ...

  15. THE MYSTERY OF THE σ-BUMP—A NEW SIGNATURE FOR MAJOR MERGERS IN EARLY-TYPE GALAXIES?

    Energy Technology Data Exchange (ETDEWEB)

    Schauer, Anna Therese Phoebe; Remus, Rhea-Silvia; Burkert, Andreas [Universitäts-Sternwarte München, Scheinerstrasse 1, D-81679 München (Germany); Johansson, Peter H., E-mail: aschauer@usm.uni-muenchen.de [Department of Physics, University of Helsinki, Gustaf Hällströmin katu 2a, FI-00014 Helsinki (Finland)

    2014-03-10

    The stellar velocity dispersion as a function of the galactocentric radius of an early-type galaxy can generally be well approximated by a power law σ∝r {sup β}. However, some observed dispersion profiles show a deviation from this fit at intermediate radii, usually between one and three R {sub eff}, where the velocity dispersion remains constant with radius, showing a bump-like behavior, which we term the {sup σ-}bump. To understand the origin of this σ-bump, we study a set of simulated early-type galaxies formed in major mergers. We find the σ-bump in all of our simulated early-type galaxies, with the size and position of the bump slightly varying from galaxy to galaxy, suggesting that the bump is a characteristic of the major merger formation scenario. The feature can be seen both in the intrinsic and projected stellar velocity dispersions. In contrast to shells that form during the merger event but evolve with time and finally disappear, the σ-bump stays nearly constant with radius and is a permanent feature that is preserved until the end of the simulation. The σ-bump is not seen in the dark matter and gas components and we therefore conclude that it is a purely stellar feature of merger remnants.

  16. Major Merger Galaxy Pairs at z=0: Dust Properties and Companion Morphology

    CERN Document Server

    Domingue, Donovan L; Xu, C Kevin; Jarrett, Thomas H; Ronca, Joseph; Hill, Emily; Jacques, Allison

    2016-01-01

    We present an analysis of dust properties of a sample of close major-merger galaxy pairs selected by K_s magnitude and redshift. The pairs represent the two populations of spiral-spiral (S+S) and mixed morphology spiral-elliptical (S+E). The CIGALE (Code Investigating GALaxy Emission) is used to fit dust models to the 2MASS, WISE and Herschel flux density measurements and derive the parameters describing the PAH contribution, interstellar radiation field (ISRF) and photo-dissociation regions (PDRs). Model fits verify our previous Spitzer Space Telescope analysis that S+S and S+E pairs do not have the same level of enhancement of star formation and differ in dust composition. The spirals of mixed morphology galaxy pairs do not exhibit the enhancements in interstellar radiation field and therefore dust temperature for spirals in S+S pairs in contrast to what would be expected according to standard models of gas redistribution due to encounter torques. This suggests the importance of the companion environment/mo...

  17. The Multiphase Structure and Power Sources of Galactic Winds in Major Mergers

    CERN Document Server

    Rupke, David S N

    2013-01-01

    Massive, galaxy-scale outflows are known to be ubiquitous in major mergers of disk galaxies in the local universe. In this paper, we explore the multiphase structure and power sources of galactic winds in six ultraluminous infrared galaxies (ULIRGs) at z < 0.06 using deep integral field spectroscopy with the Gemini Multi-Object Spectrograph (GMOS) on Gemini North. We probe the neutral, ionized, and dusty gas phases using Na I D, strong emission lines ([O I], Halpha, and [N II]), and continuum colors, respectively. We separate outflow motions from those due to rotation and tidal perturbations, and find that all of the galaxies in our sample host high-velocity flows on kiloparsec scales. The properties of these outflows are consistent with multiphase (ionized, neutral, and dusty) collimated bipolar winds emerging along the minor axis of the nuclear disk to scales of 1-2 kpc. In two cases, these collimated winds take the form of bipolar superbubbles, identified by clear kinematic signatures. Less collimated (...

  18. SPITZER IRS SPECTRAL MAPPING OF THE TOOMRE SEQUENCE: SPATIAL VARIATIONS OF PAH, GAS, AND DUST PROPERTIES IN NEARBY MAJOR MERGERS

    Energy Technology Data Exchange (ETDEWEB)

    Haan, S.; Armus, L.; Laine, S.; Surace, J. A.; Diaz-Santos, T.; Beirao, P.; Stierwalt, S. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion (Greece); Smith, J. D. [Ritter Astrophysical Observatory, University of Toledo, Toledo, OH 43606 (United States); Schweizer, F.; Murphy, E. J. [Observatories of the Carnegie Institution, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Brandl, B. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Evans, A. S.; Hibbard, J. E. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Yun, M. [Astronomy Department, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Jarrett, T. H. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

    2011-12-01

    We have mapped the key mid-IR diagnostics in eight major merger systems of the Toomre sequence (NGC 4676, NGC 7592, NGC 6621, NGC 2623, NGC 6240, NGC 520, NGC 3921, and NGC 7252) using the Spitzer Infrared Spectrograph. With these maps, we explore the variation of the ionized-gas, polycyclic aromatic hydrocarbon (PAH), and warm gas (H{sub 2}) properties across the sequence and within the galaxies. While the global PAH interband strength and ionized gas flux ratios ([Ne III]/[Ne II]) are similar to those of normal star-forming galaxies, the distribution of the spatially resolved PAH and fine structure line flux ratios is significantly different from one system to the other. Rather than a constant H{sub 2}/PAH flux ratio, we find that the relation between the H{sub 2} and PAH fluxes is characterized by a power law with a roughly constant exponent (0.61 {+-} 0.05) over all merger components and spatial scales. While following the same power law on local scales, three galaxies have a factor of 10 larger integrated (i.e., global) H{sub 2}/PAH flux ratio than the rest of the sample, even larger than what it is in most nearby active galactic nuclei. These findings suggest a common dominant excitation mechanism for H{sub 2} emission over a large range of global H{sub 2}/PAH flux ratios in major mergers. Early-merger systems show a different distribution between the cold (CO J = 1-0) and warm (H{sub 2}) molecular gas components, which is likely due to the merger interaction. Strong evidence for buried star formation in the overlap region of the merging galaxies is found in two merger systems (NGC 6621 and NGC 7592) as seen in the PAH, [Ne II], [Ne III], and warm gas line emission, but with no apparent corresponding CO (J = 1-0) emission. The minimum of the 11.3/7.7 {mu}m PAH interband strength ratio is typically located in the nuclei of galaxies, while the [Ne III/[Ne II] ratio increases with distance from the nucleus. Our findings also demonstrate that the variations of

  19. Major galaxy mergers and the growth of supermassive black holes in quasars.

    Science.gov (United States)

    Treister, Ezequiel; Natarajan, Priyamvada; Sanders, David B; Urry, C Megan; Schawinski, Kevin; Kartaltepe, Jeyhan

    2010-04-30

    Despite observed strong correlations between central supermassive black holes (SMBHs) and star formation in galactic nuclei, uncertainties exist in our understanding of their coupling. We present observations of the ratio of heavily obscured to unobscured quasars as a function of cosmic epoch up to z congruent with 3 and show that a simple physical model describing mergers of massive, gas-rich galaxies matches these observations. In the context of this model, every obscured and unobscured quasar represents two distinct phases that result from a massive galaxy merger event. Much of the mass growth of the SMBH occurs during the heavily obscured phase. These observations provide additional evidence for a causal link between gas-rich galaxy mergers, accretion onto the nuclear SMBH, and coeval star formation.

  20. The NGC 4013 tale: a pseudo-bulged, late-type spiral shaped by a major merger

    CERN Document Server

    Wang, Jianling; Puech, Mathieu; Yang, Yanbin; Flores, Hector

    2015-01-01

    Many spiral galaxy haloes show stellar streams with various morphologies when observed with deep images. The origin of these tidal features is discussed, either coming from a satellite infall or caused by residuals of an ancient, gas-rich major merger. By modelling the formation of the peculiar features observed in the NGC 4013 halo, we investigate their origin. By using GADGET -2 with implemented gas cooling, star formation, and feedback, we have modelled the overall NGC 4013 galaxy and its associated halo features. A gas-rich major merger occurring 2.7-4.6 Gyr ago succeeds in reproducing the NGC 4013 galaxy properties, including all the faint stellar features, strong gas warp, boxy-shaped halo and vertical 3.6 mum luminosity distribution. High gas fractions in the progenitors are sufficient to reproduce the observed thin and thick discs, with a small bulge fraction, as observed. A major merger is able to reproduce the overall NGC 4013 system, including the warp strength, the red colour and the high stellar ...

  1. THE MULTIPHASE STRUCTURE AND POWER SOURCES OF GALACTIC WINDS IN MAJOR MERGERS

    Energy Technology Data Exchange (ETDEWEB)

    Rupke, David S. N. [Department of Physics, Rhodes College, Memphis, TN 38112 (United States); Veilleux, Sylvain, E-mail: drupke@gmail.com [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

    2013-05-01

    Massive, galaxy-scale outflows are known to be ubiquitous in major mergers of disk galaxies in the local universe. In this paper, we explore the multiphase structure and power sources of galactic winds in six ultraluminous infrared galaxies (ULIRGs) at z < 0.06 using deep integral field spectroscopy with the Gemini Multi-Object Spectrograph (GMOS) on Gemini North. We probe the neutral, ionized, and dusty gas phases using Na I D, strong emission lines ([O I], H{alpha}, and [N II]), and continuum colors, respectively. We separate outflow motions from those due to rotation and tidal perturbations, and find that all of the galaxies in our sample host high-velocity flows on kiloparsec scales. The properties of these outflows are consistent with multiphase (ionized, neutral, and dusty) collimated bipolar winds emerging along the minor axis of the nuclear disk to scales of 1-2 kpc. In two cases, these collimated winds take the form of bipolar superbubbles, identified by clear kinematic signatures. Less collimated (but still high-velocity) flows are also present on scales up to 5 kpc in most systems. The three galaxies in our sample with obscured QSOs host higher velocity outflows than those in the three galaxies with no evidence for an active galactic nucleus. The peak outflow velocity in each of the QSOs is in the range 1450-3350 km s{sup -1}, and the highest velocities (2000-3000 km s{sup -1}) are seen only in ionized gas. The outflow energy and momentum in the QSOs are difficult to produce from a starburst alone, but are consistent with the QSO contributing significantly to the driving of the flow. Finally, when all gas phases are accounted for, the outflows are massive enough to provide negative feedback to star formation.

  2. MAJOR MERGERS WITH SMALL GALAXIES: THE DISCOVERY OF A MAGELLANIC-TYPE GALAXY AT z = 0.12

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Andreas; Frank, Matthias J. [Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, D-69117 Heidelberg (Germany); Pasquali, Anna [Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut, Mönchhofstrasse 12, D-69117 Heidelberg (Germany); Rich, R. Michael [University of California Los Angeles, Department of Physics and Astronomy, Los Angeles, CA (United States); Rabitz, Andreas, E-mail: akoch@lsw.uni-heidelberg.de [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany)

    2015-12-20

    We report on the serendipitous discovery of a star-forming galaxy at redshift z = 0.116 with morphological features that indicate an ongoing merger. This object exhibits two clearly separated components with significantly different colors, plus a possible tidal stream. Follow-up spectroscopy of the bluer component revealed a low star-forming activity of 0.09 M{sub ⊙} yr{sup −1} and a high metallicity of 12 + log(O/H) = 8.6. Based on comparison with mass–star formation-rate and mass–metallicity relations, and on fitting of spectral energy distributions, we obtain a stellar mass of 3 × 10{sup 9} M{sub ⊙}, which renders this object comparable to the Large Magellanic Cloud. Thus our finding provides a further piece of evidence of a major merger already acting on small, dwarf-galaxy-like scales.

  3. Major mergers with small galaxies - the discovery of a Magellanic-type galaxy at z=0.12

    CERN Document Server

    Koch, Andreas; Pasquali, Anna; Rich, R Michael; Rabitz, Andreas

    2015-01-01

    We report on the serendipitous discovery of a star-forming galaxy at redshift z=0.116 with morphological features that indicate an ongoing merger. This object exhibits two clearly separated components with significantly different colors, plus a possible tidal stream. Follow-up spectroscopy of the bluer component revealed a low star-forming activity of 0.09 M$_{\\odot}$/year and a high metallicity of 12+log(O/H)=8.6. Based on comparison with mass-star-formation-rate and mass-metallicity relations, and on fitting of spectral energy distributions, we obtain a stellar mass of 3x10$^9$ M$_{\\odot}$, which renders this object comparable to the Large Magellanic Cloud (LMC). Thus our finding provides a further piece of evidence of a major merger already acting on small, dwarf galaxy-like scales.

  4. Halo Occupation Distributions of Moderate X-ray AGNs through Major and Minor Mergers in a $\\Lambda$-CDM Cosmology

    CERN Document Server

    Altamirano-Dévora, L; Aceves, H; Castro, A; Cañas, R; Tamayo, F

    2015-01-01

    Motivated by recent inferred form of the halo occupation distribution (HOD) of X-ray selected AGNs, in the COSMOS field by Allevato et al. (2012), we investigate the HOD properties of moderate X-ray luminosity Active Galactic Nuclei (mXAGNs) using a simple model based on merging activity between dark matter halos (DMHs) in a $\\Lambda$-CDM cosmology. The HODs and number densities of the simulated mXAGNs at $z=0.5$, under the above scenarios to compare with Allevato et al. (2012) results. We find that the simulated HODs of major and minor mergers, and the observed for mXAGNs are consistent among them. Our main result is that minor mergers, contrary to what one might expect, can play an important role in activity mAGNs.

  5. EVIDENCE FOR A GAS-RICH MAJOR MERGER IN A PROTO-CLUSTER AT z = 2.5

    Energy Technology Data Exchange (ETDEWEB)

    Tadaki, Ken-ichi; Kodama, Tadayuki; Hayashi, Masao; Koyama, Yusei; Hatsukade, Bunyo [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Tamura, Yoichi; Kohno, Kotaro; Suzuki, Kenta [Institute of Astronomy, The University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Shimakawa, Rhythm [Department of Astronomical Science, The Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588 (Japan); Tanaka, Ichi, E-mail: tadaki.ken@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, 650 North A' ohoku Place, Hilo, HI 96720 (United States)

    2014-06-20

    Gas-rich major mergers in high-redshift proto-clusters are important events, perhaps leading to the creation of the slowly rotating remnants seen in the cores of clusters in the present day. Here, we present a deep Jansky Very Large Array observation of CO J = 1-0 emission line in a proto-cluster at z = 2.5, USS1558-003. The target field is an extremely dense region, where 20 Hα emitters (HAEs) are clustering. We have successfully detected the CO emission line from three HAEs and discovered a close pair of red and blue CO-emitting HAEs. Given their close proximity (∼30 kpc), small velocity offset (∼300 km s{sup –1}), and similar stellar masses, they could be in the early phase of a gas-rich major merger. For the red HAE, we derive a total infrared luminosity of L {sub IR} = 5.1 × 10{sup 12} L {sub ☉} using MIPS 24 μm and radio continuum images. The L{sub IR}/L{sub CO}{sup ′} ratio is significantly enhanced compared to local spirals and high-redshift disks with a similar CO luminosity, which is indicative of a starburst mode. We find the gas depletion timescale is shorter than that of normal star-forming galaxies regardless of adopted CO-H{sub 2} conversion factors. The identification of such a rare event suggests that gas-rich major mergers frequently take place in proto-clusters at z > 2 and may involve the formation processes of slow rotators seen in local massive clusters.

  6. The XXL survey XV: Evidence for dry merger driven BCG growth in XXL-100-GC X-ray clusters

    CERN Document Server

    Lavoie, S; Democles, J; Eckert, D; Gastaldello, F; Smith, G P; Lidman, C; Adami, C; Pacaud, F; Pierre, M; Clerc, N; Giles, P; Lieu, M; Chiappetti, L; Altieri, B; Ardila, F; Baldry, I; Bongiorno, A; Desai, S; Elyiv, A; Faccioli, L; Gardner, B; Garilli, B; Groote, M W; Guennou, L; Guzzo, L; Hopkins, A M; Liske, J; McGee, S; Melnyk, O; Owers, M S; Poggianti, B; Ponman, T J; Scodeggio, M; Spitler, L; Tuffs, R J

    2016-01-01

    The growth of brightest cluster galaxies is closely related to the properties of their host cluster. We present evidence for dry mergers as the dominant source of BCG mass growth at $z\\lesssim1$ in the XXL 100 brightest cluster sample. We use the global red sequence, H$\\alpha$ emission and mean star formation history to show that BCGs in the sample possess star formation levels comparable to field ellipticals of similar stellar mass and redshift. XXL 100 brightest clusters are less massive on average than those in other X-ray selected samples such as LoCuSS or HIFLUGCS. Few clusters in the sample display high central gas concentration, rendering inefficient the growth of BCGs via star formation resulting from the accretion of cool gas. Using measures of the relaxation state of their host clusters, we show that BCGs grow as relaxation proceeds. We find that the BCG stellar mass corresponds to a relatively constant fraction 1\\%\\ of the total cluster mass in relaxed systems. We also show that, following a cluste...

  7. Formation of Andromeda II via a gas-rich major merger and an interaction with M31

    CERN Document Server

    Fouquet, Sylvain; del Pino, Andres; Ebrova, Ivana

    2016-01-01

    Andromeda II (And II) has been known for a few decades but only recently observations have unveiled new properties of this dwarf spheroidal galaxy. The presence of two stellar populations, the bimodal star formation history (SFH) and an unusual rotation velocity of And II put strong constrains on its formation and evolution. Following Lokas et al. (2014), we propose a detailed model to explain the main properties of And II involving (1) a gas-rich major merger between two dwarf galaxies at high redshift in the field and (2) a close interaction with M31 about 5 Gyr ago. The model is based on N-body/hydrodynamical simulations including gas dynamics, star formation and feedback. One simulation is designed to reproduce the gas-rich major merger explaining the origin of stellar populations and the SFH. Other simulations are used to study the effects of tidal forces and the ram pressure stripping during the interaction between And II and M31. The model successfully reproduces the SFH of And II including the propert...

  8. Formation of Andromeda II via a gas-rich major merger and an interaction with M31

    Science.gov (United States)

    Fouquet, Sylvain; Łokas, Ewa L.; del Pino, Andrés; Ebrová, Ivana

    2016-10-01

    Andromeda II (And II) has been known for a few decades but only recently observations have unveiled new properties of this dwarf spheroidal galaxy. The presence of two stellar populations, the bimodal star formation history (SFH) and an unusual rotation velocity of And II put strong constrains on its formation and evolution. Following Lokas et al. (2014), we propose a detailed model to explain the main properties of And II involving (1) a gas-rich major merger between two dwarf galaxies at high redshift in the field and (2) a close interaction with M31 about 5 Gyr ago. The model is based on N-body/hydrodynamical simulations including gas dynamics, star formation and feedback. One simulation is designed to reproduce the gas-rich major merger explaining the origin of stellar populations and the SFH. Other simulations are used to study the effects of tidal forces and the ram pressure stripping during the interaction between And II and M31. The model successfully reproduces the SFH of And II including the properties of stellar populations, its morphology, kinematics and the lack of gas. Further improvements to the model are possible via joint modelling of all processes and better treatment of baryonic physics.

  9. The impact of a major cluster merger on galaxy evolution in MACS\\,J0025.4-1225

    CERN Document Server

    Ma, C -J; Marshall, P; Schrabback, T

    2010-01-01

    We present results of an extensive morphological, spectroscopic, and photometric study of the galaxy population of MACS J0025.4$-$1225 (z=0.586), a major cluster merger with clear segregation of dark and luminous matter, to examine the impact of mergers on galaxy evolution. Based on 436 galaxy spectra obtained with Keck DEIMOS, we identified 212 cluster members within 4 Mpc of the cluster centre, and classified them using three spectroscopic types; we find 111 absorption-line, 90 emission-line (including 23 e(a) and 11 e(b)), and 6 E+A galaxies. The fraction of absorption(emission)-line galaxies is a monotonically increasing(decreasing) function of both projected galaxy density and radial distance to the cluster center. More importantly, the 6 observed E+A cluster members are all located between the dark-matter peaks of the cluster and within ~0.3Mpc radius of the X-ray flux peak, unlike the E+A galaxies in other intermediate-redshift clusters which are usually found to avoid the core region. In addition, we ...

  10. On the buildup of massive early-type galaxies at z<~1. I- Reconciling a significant, recent assembly through major mergers with mass-downsizing

    CERN Document Server

    Eliche-Moral, M C; Gallego, J; Barro, G; Zamorano, J; Lopez-Sanjuan, C; Balcells, M; Guzman, R; Munoz-Mateos, J C

    2010-01-01

    Several studies have tried to ascertain whether or not the increase in abundance of the early-type galaxies (E-S0a's) with time is mainly due to major mergers, reaching opposite conclusions. We have tested it directly through semi-analytical modelling, by studying how the massive early-type galaxies with log(M_*/Msun)>11 at z~0 (mETGs) would have evolved backwards-in-time, under the hypothesis that each major merger gives place to an early-type galaxy. The study was carried out just considering the major mergers strictly reported by observations at each redshift, and assuming that gas-rich major mergers experience transitory phases of dust-reddened, star-forming galaxies (DSFs). The model is able to reproduce the observed evolution of the galaxy LFs at z<~1, simultaneously for different rest-frame bands (B, I, and K) and for different selection criteria on color and morphology. It also provides a framework in which apparently-contradictory results on the recent evolution of the luminosity function (LF) of ...

  11. From major merger to radio galaxy : low surface-brightness stellar counterpart to the giant HI ring around B2 0648+27

    NARCIS (Netherlands)

    Emonts, B. H. C.; Morganti, R.; van Gorkom, J. H.; Oosterloo, T. A.; Brogt, E.; Tadhunter, C. N.

    2008-01-01

    We present the detection of a low surface-brightness stellar counterpart to an enormous (190 kpc) ring of neutral hydrogen (HI) gas that surrounds the nearby radio galaxy B2 0648+27. This system is currently in an evolutionary stage between major merger and (radio-loud) early-type galaxy. In a previ

  12. Clear evidence for the early triggering of a luminous quasar-like AGN in a major, gas rich merger

    CERN Document Server

    Bessiere, Patricia S; Almeida, Cristina Ramos; Martin, Montserrat Villar

    2013-01-01

    We present deep, intermediate resolution, long slit Gemini GMOS-S optical spectra of the SDSS type II quasar J002531-104022, which is a highly disturbed system currently undergoing a major merger event. We use these data to model the ages and reddenings of the stellar populations in three distinct spatial regions and find a remarkable uniformity in the properties of the young stellar populations (YSP) that dominate the optical spectra. The YSPs are all found to have relatively young ages (tysp < 40$ Myr), strongly implying that the latest episode of star formation and quasar activity have been triggered quasi-simultaneously. The lack of reddening deduced from both continuum modelling and the measured Balmer decrements (E(B-V) <0.3) suggests that starburst and/or AGN induced outflows have already effectively removed a substantial proportion of the gas and dust from the central region. These findings starkly contrast with model predictions which suggest an offset of a few 100 Myr between the peak of merge...

  13. PKS0347+05: a radio-loud/radio-quiet double AGN system triggered in a major galaxy merger

    CERN Document Server

    Tadhunter, C; Morganti, R; Holt, J; Rose, M; Dicken, D; Inskip, K

    2012-01-01

    We present optical, infrared and radio observations of the powerful FRII radio source PKS0347+05 (z=0.3390), and demonstrate that it is a rare example of a radio-loud/radio-quiet double AGN system, comprising a weak line radio galaxy (WLRG) separated by 25 kpc (in projection) from a Seyfert 1 nucleus at the same redshift. Our deep Gemini optical images show a highly disturbed morphology, with a warped dust lane crossing through the halo and nuclear regions of the radio galaxy host, tidal tails, and a bridge connecting the radio galaxy to the Seyfert 1 nucleus. Spectral synthesis modelling of our Gemini optical spectrum of the radio galaxy shows evidence for a reddened young stellar population of age <100 Myr. Further evidence for recent star formation activity in this source is provided by the detection of strong PAH features in mid-IR Spitzer/IRS spectra. Together, these observations support a model in which both AGN have been triggered simultaneously in a major galaxy merger. However, despite the presenc...

  14. The Luminosity Function of Quasars. Major Mergers of Haloes,Growth of Massive Black Holes and Evolving Luminosity Function of Quasars

    CERN Document Server

    Hatziminaoglou, E; Solanes, J M; Manrique, A; Salvador-Solé, E; Hatziminaoglou, Evanthia; Mathez, Guy; Solanes, Jose-Maria; Manrique, Alberto; Salvador-Sole, Eduard

    2003-01-01

    We construct a physically motivated analytical model for the quasar luminosity function, based on the joint star formation and feeding of massive black holes suggested by the observed correlation between the black hole mass and the stellar mass of the hosting spheroids. The parallel growth of massive black holes and host galaxies is assumed to take place at the occasion of major mergers suffered by haloes. The halo major merger rate is computed in the frame of the extended Press-Schechter model. The evolution of black holes on cosmological timescales is achieved by the integration of the governing set of differential equations, established from a few reasonable assumptions that account for the distinct (Eddington-limited or supply-limited) accretion regimes. Finally, the typical lightcurves of the reactivated quasars are obtained under the assumption that, in such accretion episodes, the fall of matter onto the black hole is achieved in a self-regulated stationary way. The predicted quasar luminosity function...

  15. ALMA Observations Show Major Mergers Among the Host Galaxies of Fast-growing, High-redshift​ Supermassive​ Black Holes

    Science.gov (United States)

    Trakhtenbrot, Benny; Lira, Paulina; Netzer, Hagai; Cicone, Claudia; Maiolino, Roberto; Shemmer, Ohad

    2017-02-01

    We present new ALMA band-7 data for a sample of six luminous quasars at z≃ 4.8, powered by fast-growing supermassive black holes (SMBHs) with rather uniform properties: the typical accretion rates and black hole masses are L/{L}{Edd}≃ 0.7 and {M}{BH}≃ {10}9 {M}ȯ . Our sample consists of three “FIR-bright” sources, which were individually detected in previous Herschel/SPIRE observations, with star formation rates of {SFR}> 1000 {M}ȯ {{yr}}-1, and three “FIR-faint” sources for which Herschel stacking analysis implies a typical SFR of ∼400 {M}ȯ {{yr}}-1. The dusty interstellar medium in the hosts of all six quasars is clearly detected in the ALMA data and resolved on scales of ∼2 kpc, in both continuum ({λ }{rest}∼ 150 μ {{m}}) and [{{C}} {{II}}] λ 157.74 μ {{m}} line emission. The continuum emission is in good agreement with the expectations from the Herschel data, confirming the intense SF activity in the quasar hosts. Importantly, we detect companion sub-millimeter galaxies (SMGs) for three sources—one FIR-bright and two FIR-faint, separated by ∼ 14{--}45 {kpc} and ALMA data therefore clearly support the idea that major mergers are important drivers for rapid early SMBH growth. However, the fact that not all high-SFR quasar hosts are accompanied by interacting SMGs and the gas kinematics as observed by ALMA suggest that other processes may be fueling these systems. Our analysis thus demonstrates the diversity of host galaxy properties and gas accretion mechanisms associated with early and rapid SMBH growth.

  16. HERSCHEL OBSERVATIONS OF MAJOR MERGER PAIRS AT z = 0: DUST MASS AND STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chen [School of Space Science and Physics, Shandong University, Weihai, Weihai, Shandong 264209 (China); Xu, Cong Kevin; Lu, Nanyao; Mazzarella, Joe [Infrared Processing and Analysis Center, California Institute of Technology 100-22, Pasadena, CA 91125 (United States); Domingue, Donovan; Ronca, Joseph; Jacques, Allison [Georgia College and State University, CBX 82, Milledgeville, GA 31061 (United States); Buat, Veronique [Laboratoire d’Astrophysique de Marseille—LAM, Université d’Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cheng, Yi-Wen [Institute of Astronomy, National Central University, Chung-Li 32054, Taiwan (China); Gao, Yu [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Huang, Jiasheng [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Jarrett, Thomas H. [Astronomy Department, University of Cape Town, Rondebosch 7701 (South Africa); Lisenfeld, Ute [Departamento de Fisica Teórica y del Cosmos, Universidad de Granada (Spain); Sun, Wei-Hsin [Institute of Astrophysics, National Taiwan University and The National Museum of Natural Science, Taiwan (China); Wu, Hong [National Astronomical Observatories, Chinese Academy of Sciences, Beijing (China); Yun, Min S., E-mail: caochen@sdu.edu.cn, E-mail: cxu@ipac.caltech.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2016-02-15

    We present Herschel PACS and SPIRE far-infrared (FIR) and submillimeter imaging observations for a large K-band selected sample of 88 close major-merger pairs of galaxies (H-KPAIRs) in 6 photometric bands (70, 100, 160, 250, 350, and 500 μm). Among 132 spiral galaxies in the 44 spiral–spiral (S+S) pairs and 44 spiral–elliptical (S+E) pairs, 113 are detected in at least 1 Herschel band. The star formation rate (SFR) and dust mass (M{sub dust}) are derived from the IR SED fitting. The mass of total gas (M{sub gas}) is estimated by assuming a constant dust-to-gas mass ratio of 0.01. Star-forming spiral galaxies (SFGs) in S+S pairs show significant enhancements in both specific star formation rate (sSFR) and star formation efficiency (SFE), while having nearly the same gas mass compared to control galaxies. On the other hand, for SFGs in S+E pairs, there is no significant sSFR enhancement and the mean SFE enhancement is significantly lower than that of SFGs in S+S pairs. This suggests an important role for the disk–disk collision in the interaction-induced star formation. The M{sub gas} of SFGs in S+E pairs is marginally lower than that of their counterparts in both S+S pairs and the control sample. Paired galaxies with and without interaction signs do not differ significantly in their mean sSFR and SFE. As found in previous works, this much larger sample confirms that the primary and secondary spirals in S+S pairs follow a Holmberg effect correlation on sSFR.

  17. HALO OCCUPATION DISTRIBUTIONS OF MODERATE X-RAY AGNS FORMED THROUGH MAJOR AND MINOR MERGERS IN A Λ-CDM COSMOLOGY

    Directory of Open Access Journals (Sweden)

    L. Altamirano-Dévora

    2016-01-01

    Full Text Available Motivated by the shape of the halo occupation distribution (HOD of Xray selected AGNs in the COSMOS field recently inferred by Allevato et al., we investigated the HOD properties of moderate X-ray luminosity active galactic nuclei (mXAGNs using a simple model based on the merging activity between dark matter halos (DMHs in a ΛCDM cosmology. The HODs and number densities of the simulated mXAGNs at z = 0 .5, under the above scenarios were compared with the results of Allevato et al. We found that the simulated HODs of major and minor mergers, and the observed HODs of mXAGNs are consistent. Our main result is that minor mergers, contrary to what one might expect, can play an important role in the activity of mAGNs.

  18. Effect of drying methods on the discoloration of three major domestic softwood species in Korea

    Institute of Scientific and Technical Information of China (English)

    Ho-yang Kang

    2006-01-01

    Japanese pine, Korean pine and larch are three major softwood species in Korea. Their colors are relatively light, thus easily discolored due to drying and UV irradiation. In this study, they were dried with five different drying methods, steam treated and exposed to weathering. Their colors were measured using a spectrophotometer and comparisons made both among species and drying methods. For Japanese and Korean pines, high temperature dried and steam-dried specimens showed distinct color differences compared with the controls. Steam treatment discolored the dried specimens of Japanese and Korean pines but did not discolor those of larch. After weathering for 144 days the specimens of Japanese pine showed slight color differences among drying methods.

  19. From major merger to radio galaxy: low surface-brightness stellar counterpart to the giant HI ring around B2 0648+27

    CERN Document Server

    Emonts, B H C; Van Gorkom, J H; Oosterloo, T A; Brogt, E; Tadhunter, C N

    2008-01-01

    We present the detection of a low surface-brightness stellar counterpart to an enormous (190 kpc) ring of neutral hydrogen (HI) gas that surrounds the nearby radio galaxy B2 0648+27. This system is currently in an evolutionary stage between major merger and (radio-loud) early-type galaxy. In a previous paper we investigated in detail the timescales between merger, starburst and AGN activity in B2 0648+27, based on its unusual multi-wavelength properties (large-scale HI ring, dominating post-starburst stellar population and infra-red luminosity). In this Research Note we present deep optical B- and V-band imaging that provides further evidence for the merger origin of B2 0648+27. The host galaxy shows a distorted optical morphology and a broad tidal arm is clearly present. A low surface-brightness stellar tail or partial ring curls around more than half the host galaxy at a distance of up to 55 kpc from the centre of the galaxy, following the large-scale, ring-like HI structure that we detected previously arou...

  20. Effects of dry period length on clinical mastitis and other major clinical health disorders

    DEFF Research Database (Denmark)

    Enevoldsen, Carsten; Sørensen, J.T.

    1992-01-01

    Four, 7-, and 10-wk dry periods were randomly assigned to 366 dairy cows in eight herds. A multiple polytomous logistic regression analysis was conducted with the objective to reveal possible important effects of the dry period on the risk of contracting major clinical health disorders. Several...... calving intervals, the risk of occurrence of complications at calving decreased with the length of the dry period. This relation was reversed at longer calving intervals. Dry period lengths of approximately 7 wk appear to be associated with the lowest risk of clinical health disorders, but other factors...

  1. The Mice at play in the CALIFA survey: A case study of a gas-rich major merger between first passage and coalescence

    CERN Document Server

    ,

    2014-01-01

    We present optical integral field spectroscopy (IFS) observations of the Mice, a major merger between two massive (>10^11Msol) gas-rich spirals NGC4676A and B, observed between first passage and final coalescence. The spectra provide stellar and gas kinematics, ionised gas properties and stellar population diagnostics, over the full optical extent of both galaxies. The Mice provide a perfect case study highlighting the importance of IFS data for improving our understanding of local galaxies. The impact of first passage on the kinematics of the stars and gas has been significant, with strong bars likely induced in both galaxies. The barred spiral NGC4676B exhibits a strong twist in both its stellar and ionised gas disk. On the other hand, the impact of the merger on the stellar populations has been minimal thus far: star formation induced by the recent close passage has not contributed significantly to the global star formation rate or stellar mass of the galaxies. Both galaxies show bicones of high ionisation...

  2. Host galaxies of luminous z$\\sim$0.6 quasars: Major mergers are not prevalent at the highest AGN luminosities

    CERN Document Server

    Villforth, C; Pawlik, M M; Hewlett, T; Rowlands, K; Herbst, H; Shankar, F; Fontana, A; Hamann, F; Koekemoer, A; Pforr, J; Trump, J; Wuyts, S

    2016-01-01

    Galaxy interactions are thought to be one of the main triggers of Active Galactic Nuclei (AGN), especially at high luminosities, where the accreted gas mass during the AGN lifetime is substantial. Evidence for a connection between mergers and AGN, however, remains mixed. Possible triggering mechanisms remain particularly poorly understood for luminous AGN, which are thought to require triggering by major mergers, rather than secular processes. We analyse the host galaxies of a sample of 20 optically and X-ray selected luminous AGN (log($L_{bol}$ [erg/s]) $>$ 45) at z $\\sim$ 0.6 using HST WFC3 data in the F160W/H band. 15/20 sources have resolved host galaxies. We create a control sample of mock AGN by matching the AGN host galaxies to a control sample of non-AGN galaxies. Visual signs of disturbances are found in about 25% of sources in both the AGN hosts and control galaxies. Using both visual classification and quantitative morphology measures, we show that the levels of disturbance are not enhanced when co...

  3. Evolutionary paths among different red galaxy types at 0.3 < z < 1.5 and the late buildup of massive E-S0's through major mergers

    CERN Document Server

    Prieto, Mercedes; Balcells, Marc; Cristobal-Hornillos, David; Erwin, Peter; Abreu, David; Dominguez-Palmero, Lilian; Hempel, Angela; Lopez-Sanjuan, Carlos; Guzman, Rafael; Perez-Gonzalez, Pablo G; Barro, Guillermo; Gallego, Jesus; Zamorano, Jaime

    2012-01-01

    Some recent observations seem to disagree with hierarchical theories of galaxy formation about the role played by major mergers in the late buildup of massive E-S0's. We re-address this question by analysing the morphology, structural distortion level, and star formation enhancement of a sample of massive galaxies (M_* > 5 * 10^10 Msun) lying on the Red Sequence and its surroundings at 0.3 10^11 Msun at z=0 through gas-rich major mergers has frozen since z~0.6. All these facts support that major mergers have played the dominant role in the definitive buildup of present-day E-S0's with M_*> 10^11 Msun at 0.6

  4. Merger and acquisition medicine.

    Science.gov (United States)

    Powell, G S

    1997-01-01

    This discussion of the ramifications of corporate mergers and acquisitions for employees recognizes that employee adaptation to the change can be a long and complex process. The author describes a role the occupational physician can take in helping to minimize the potential adverse health impact of major organizational change.

  5. Mergers + acquisitions.

    Science.gov (United States)

    Hoppszallern, Suzanna

    2002-05-01

    The hospital sector in 2001 led the health care field in mergers and acquisitions. Most deals involved a network augmenting its presence within a specific region or in a market adjacent to its primary service area. Analysts expect M&A activity to increase in 2002.

  6. Mergers & Acquisitions

    DEFF Research Database (Denmark)

    Fomcenco, Alex

    and functioning of provisions of European federal corporate law and internationally accepted principles of the law of obligations. This book, however, is not about clarification of the reasons that urge for M&A operations, nor is it about judging the outcome of the transactions. It is about synthesizing......MERGERS & ACQUISITIONS: Counseling and Choice of Method describes and analyzes the current state of law in Europe in regard to some relevant selected elements related to mergers and acquisitions, and the adviser’s counsel in this regard. The focus is aimed and maintained at application......, on the one hand, the methods of M&A and, on the other hand, several selected key elements. Any participating party - as well as their respective advisers - must be aware of these elements prior, throughout, and after the transaction: consideration, succession, taxes and fiscal neutrality, group...

  7. Mergers and Bulge Formation in Lambda-CDM: Which Mergers Matter?

    CERN Document Server

    Hopkins, Philip F; Croton, Darren; Hernquist, Lars; Keres, Dusan; Khochfar, Sadegh; Stewart, Kyle; Wetzel, Andrew; Younger, Joshua D

    2009-01-01

    We use a suite of semi-empirical models to predict galaxy merger rates and contributions to bulge growth as functions of merger mass, redshift, and mass ratio. The models use empirical halo occupation constraints to identify mergers, together with high-resolution simulations to quantify how mergers with different properties contribute to the bulge population. We find good agreement with a variety of observational constraints, and provide fitting functions for merger rates and contributions to bulge growth. We identify several robust conclusions. (1) Major mergers dominate formation and assembly of L* bulges and the spheroid mass density, minor mergers contribute ~30%. (2) This is mass-dependent: bulge formation is dominated by more minor mergers in lower-mass systems. At higher masses, bulges form in major mergers near L*, but subsequently assemble in minor mergers. (3) The minor/major contribution is also morphology-dependent: higher B/T systems form in more major mergers, lower B/T systems form in situ from...

  8. Tidal Tales of Minor Mergers: Star Formation in the Tidal Debris of Minor Mergers

    CERN Document Server

    Knierman, Karen A

    2009-01-01

    How does the tidal debris of minor galaxy mergers contribute to structures in spiral galaxies or in the intergalactic medium? While major mergers are known to create structures such as tidal dwarf galaxies and star clusters within their tidal debris, less is known about minor mergers (mass ratios between a dwarf galaxy and disk galaxy of less than one-third) and their tidal debris. This work surveys 6 nearby minor mergers using optical broad-band and H-alpha narrow-band imaging to characterize star formation in their tidal debris. Young star clusters with ages less than the dynamical age of the tidal tails are found in all 6 mergers, indicating that the star clusters formed in situ. Even if minor mergers contribute less tidal debris per interaction than major mergers, they are more common and possibly contribute structure to all types of galaxies and to the intergalactic medium throughout the history of the universe.

  9. The Role of Major Gas-rich Mergers on the Evolution of Galaxies from the Blue Cloud to the Red Sequence

    Science.gov (United States)

    Guo, Rui; Hao, Cai-Na; Xia, X. Y.; Mao, Shude; Shi, Yong

    2016-07-01

    With the aim of exploring the fast evolutionary path from the blue cloud of star-forming galaxies to the red sequence of quiescent galaxies in the local universe, we select a local advanced merging infrared luminous and ultraluminous galaxy (adv-merger (U)LIRGs) sample and perform careful dust extinction corrections to investigate their positions in the star formation rate-M *, u - r, and NUV - r color-mass diagrams. The sample consists of 89 (U)LIRGs at the late merger stage, obtained from cross-correlating the Infrared Astronomical Satellite Point Source Catalog Redshift Survey and 1 Jy ULIRGs samples with the Sloan Digital Sky Survey DR7 database. Our results show that 74 % +/- 5 % of adv-merger (U)LIRGs are localized above the 1σ line of the local star-forming galaxy main sequence. We also find that all adv-merger (U)LIRGs are more massive than and as blue as the blue cloud galaxies after corrections for Galactic and internal dust extinctions, with 95 % +/- 2 % and 81 % +/- 4 % of them outside the blue cloud on the u - r and NUV - r color-mass diagrams, respectively. These results, combined with the short timescale for exhausting the molecular gas reservoir in adv-merger (U)LIRGs (3× {10}7 to 3× {10}8 years), imply that the adv-merger (U)LIRGs are likely at the starting point of the fast evolutionary track previously proposed by several groups. While the number density of adv-merger (U)LIRGs is only ˜ 0.1 % of the blue cloud star-forming galaxies in the local universe, this evolutionary track may play a more important role at high redshift.

  10. Evolution along the sequence of S0 Hubble types induced by dry minor mergers. I - Global bulge-to-disk structural relations

    CERN Document Server

    Eliche-Moral, M Carmen; Aguerri, J Alfonso L; Gallego, Jesus; Zamorano, Jaime; Balcells, Marc; Prieto, Mercedes

    2012-01-01

    Recent studies have argued that galaxy mergers are not important drivers for the evolution of S0's, on the basis that mergers cannot preserve the coupling between the bulge and disk scale-lengths observed in these galaxies and the lack of correlation of their ratio with the S0 Hubble type. We investigate whether the remnants resulting from collision-less N-body simulations of intermediate and minor mergers onto S0 galaxies evolve fulfilling global structural relations observed between the bulges and disks of these galaxies. Different initial bulge-to-disk ratios of the primary S0 have been considered, as well as different satellite densities, mass ratios, and orbits of the encounter. We have analysed the final morphology of the remnants in images simulating the typical observing conditions of S0 surveys. We derive bulge+disk decompositions of the final remnants to compare their global bulge-to-disk structure with observations. We show that all remnants present undisturbed S0 morphologies according to the pres...

  11. Mergers & Acquisitions

    DEFF Research Database (Denmark)

    Fomcenco, Alex

    This dissertation is a legal dogmatic thesis, the goal of which is to describe and analyze the current state of law in Europe in regard to some relevant selected elements related to mergers and acquisitions, and the adviser’s counsel in this regard. Having regard to the topic of the dissertation...... the focus is aimed and maintained at application and functioning of provisions of European federal corporate law and internationally accepted principles of the law of obligations. This study, however, is not about clarification of the reasons that urge for M&A operations, nor is it about judging the results...... of the transactions. This study is about synthesizing, on the one hand, the methods of M&A, and, on the other hand, several selected key elements, which any participating party, as well as their respective advisers, must be aware of, prior, throughout, and after the transaction: consideration, succession, taxes...

  12. The role of major gas-rich mergers on the evolution of galaxies from the blue cloud to the red sequence

    CERN Document Server

    Guo, Rui; Xia, X Y; Mao, Shude; Shi, Yong

    2016-01-01

    With the aim of exploring the fast evolutionary path from the blue cloud of star-forming galaxies to the red sequence of quiescent galaxies in the local universe, we select a local advanced merging infrared luminous and ultraluminous galaxy (adv-merger (U)LIRGs) sample and perform careful dust extinction corrections to investigate their positions in the SFR-$M_{\\ast}$, u-r and NUV-r color-mass diagrams. The sample consists of 89 (U)LIRGs at the late merger stage, obtained from cross-correlating the IRAS Point Source Catalog Redshift Survey and 1 Jy ULIRGs samples with the Sloan Digital Sky Survey DR7 database. Our results show that $74\\%\\pm 5\\%$ of adv-merger (U)LIRGs are localized above the $1\\, \\sigma$ line of the local star-forming galaxy main sequence. We also find that all adv-merger (U)LIRGs are more massive than and as blue as the blue cloud galaxies after corrections of Galactic and internal dust extinctions, with $95\\%\\pm 2\\%$ and $81\\%\\pm 4\\%$ of them outside the blue cloud on the u-r and NUV-r colo...

  13. The University of Johannesburg merger: Academics experience of the pre-merger phase

    Directory of Open Access Journals (Sweden)

    G. A. Goldman

    2006-12-01

    Full Text Available Purpose of the study: The aim of this study is to gain an understanding of the merger experiences academic staff were exposed to during the pre-merger phase of the University of Johannesburg merger. Of particular interest is how these experiences translate into acceptance of the merger amongst academic staff. The study was borne out of the transformation of the higher education landscape in South Africa, which is typified by a spate of mergers between higher education institutions. Design/methodology/approach: As the purpose of the study was, inter alia, aimed at understanding the merger experiences of academic staff, the study was conducted according to an interpretive research paradigm, where interpretation of data calls for an insider perspective, in order to "see things through their eyes" as it were. In this regard, a qualitative methodology was employed. Findings: Findings indicate that academic staff members at the University of Johannesburg experience two distinct mental states during the pre-merger phase. Following the announcement of the merger, reaction and experience tend to be emotionally driven but as merging efforts become more concrete over time, this emotive state is replaced by a more rationally driven disposition. Implications: The distinction between an emotive and rational demeanour during the pre-merger phase of a merger affords managers and leaders the opportunity to plan change interventions in such a way that irrational, emotive responses and behaviour do not hamper progress in terms of merger implementation. In a more general sense, this study highlights the process of transition individual staff members pass through as they have to come to terms with the changes brought about by a merger. Originality / Value: The majority of merger literature, as well as change literature, focuses on the organisational context of change during a merger. Limited literature exists on the personal effects of a change event such as a

  14. Mergers in Lambda-CDM: Uncertainties in Theoretical Predictions and Interpretations of the Merger Rate

    CERN Document Server

    Hopkins, Philip F; Bundy, Kevin; Khochfar, Sadegh; Bosch, Frank van den; Somerville, Rachel S; Wetzel, Andrew; Keres, Dusan; Hernquist, Lars; Stewart, Kyle; Younger, Joshua D; Genel, Shy; Ma, Chung-Pei

    2010-01-01

    Different methodologies lead to order-of-magnitude variations in predicted galaxy merger rates. We examine and quantify the dominant uncertainties. Different halo merger rates and subhalo 'destruction' rates agree to within a factor ~2 given proper care in definitions. If however (sub)halo masses are not appropriately defined or are under-resolved, the major merger rate can be dramatically suppressed. The dominant differences in galaxy merger rates owe to baryonic physics. Hydrodynamic simulations without feedback and older models that do not agree with the observed galaxy mass function propagate factor ~5 bias in the resulting merger rates. However, if the model matches the galaxy mass function, properties of central galaxies are sufficiently converged to give small differences in merger rates. But variations in baryonic physics of satellites have the most dramatic effect. The known problem of satellite 'over-quenching' in most semi-analytic models (SAMs), whereby SAM satellites are too efficiently stripped ...

  15. Surviving mergers & acquisitions.

    Science.gov (United States)

    Dixon, Diane L

    2002-01-01

    Mergers and acquisitions are never easy to implement. The health care landscape is a minefield of failed mergers and uneasy alliances generating great turmoil and pain. But some mergers have been successful, creating health systems that benefit the communities they serve. Five prominent leaders offer their advice on minimizing the difficulties of M&As.

  16. Estimation of dry deposition fluxes of major inorganic species by canopy throughfall approach

    Institute of Scientific and Technical Information of China (English)

    JIN Lei; SHAO Min; ZENG Limin; ZHAO Dawei; TANG Dagang

    2006-01-01

    Dry deposition in China has not yet been intensively studied even though it constitutes an important pathway for acid deposition. The total deposition was monitored at Tieshanping catchment, a regional remote site in Chongqing City. The dry deposition loads of sulphur, calcium and nitrogen are estimated by using a canopy throughfall approach. The results indicate that the annual dry deposition loads of sulphur and calcium at Tieshanping site are much higher than those measured in forestry areas in other countries, while the dry deposition flux of nitrogen is at a comparable level. The dry deposition loads of sulphur, calcium and nitrogen are all higher than the wet deposition loads. Applying a canopy budget model has proven that the routine, simplified canopy throughfall approach may underestimate the dry deposition flux of nitrogen-containing species.

  17. Evaluation and intercomparison of five major dry deposition algorithms in North America

    Science.gov (United States)

    Dry deposition of various pollutants needs to be quantified in air quality monitoring networks as well as in chemical transport models. The inferential method is the most commonly used approach in which the dry deposition velocity (Vd) is empirically parameterized as a function o...

  18. Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence

    CERN Document Server

    Stewart, Kyle R; Barton, Elizabeth J; Wechsler, Risa H

    2008-01-01

    We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies--such as close pair counts, starburst counts, and the morphologically disturbed fraction--likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z=0 to z=4. We provide a simple 'universal' fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies. For example, we find that the instantaneous merger rate of m/M>0.3 mass ratio events into typical L > f L* galaxies follows the simple relation dN/dt=0.03(1+f)(1+z)^2.1 Gyr^-1. Despite the rapid increase in merger rate with redshift, only a small fraction of >0.4 L* high-redshift galaxies (~3% at z=2) should have experienced a major merger (m/M >0.3) in the very recent past (t0.3) in t...

  19. Galaxy Mergers and Dark Matter Halo Mergers in LCDM: Mass, Redshift, and Mass-Ratio Dependence

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Kyle R.; Bullock, James S.; Barton, Elizabeth J.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC

    2009-08-03

    We employ a high-resolution LCDM N-body simulation to present merger rate predictions for dark matter halos and investigate how common merger-related observables for galaxies - such as close pair counts, starburst counts, and the morphologically disturbed fraction - likely scale with luminosity, stellar mass, merger mass ratio, and redshift from z = 0 to z = 4. We provide a simple 'universal' fitting formula that describes our derived merger rates for dark matter halos a function of dark halo mass, merger mass ratio, and redshift, and go on to predict galaxy merger rates using number density-matching to associate halos with galaxies. For example, we find that the instantaneous merger rate of m/M > 0.3 mass ratio events into typical L {approx}> fL{sub *} galaxies follows the simple relation dN/dt {approx_equal} 0.03(1+f)Gyr{sup -1} (1+z){sup 2.1}. Despite the rapid increase in merger rate with redshift, only a small fraction of > 0.4L{sub *} high-redshift galaxies ({approx} 3% at z = 2) should have experienced a major merger (m/M > 0.3) in the very recent past (t < 100 Myr). This suggests that short-lived, merger-induced bursts of star formation should not contribute significantly to the global star formation rate at early times, in agreement with observational indications. In contrast, a fairly high fraction ({approx} 20%) of those z = 2 galaxies should have experienced a morphologically transformative merger within a virial dynamical time. We compare our results to observational merger rate estimates from both morphological indicators and pair-fraction based determinations between z = 0-2 and show that they are consistent with our predictions. However, we emphasize that great care must be made in these comparisons because the predicted observables depend very sensitively on galaxy luminosity, redshift, overall mass ratio, and uncertain relaxation timescales for merger remnants. We show that the majority of bright galaxies at z = 3 should have undergone a

  20. Major advances in concentrated and dry milk products, cheese, and milk fat-based spreads.

    Science.gov (United States)

    Henning, D R; Baer, R J; Hassan, A N; Dave, R

    2006-04-01

    Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have

  1. 中国矿业企业海外并购面临的主要风险及应对策略%Major risks confronting overseas mergers and acquisitions of Chinese mining enterprises and its coping strategy

    Institute of Scientific and Technical Information of China (English)

    童军虎; 孙晓

    2013-01-01

    Considering resources ,economy and national security ,Chinese enterprises “go out” strategy is necessa-ry.Data show that the overseas mergers and acquisitions pace of Chinese enterprise accelerates ,but only a small part of it prevails.Based on case study and practice of overseas mergers and acquisition of Chinese enterprises in recent years,the paper summarized major risks ,decisive factors and recommendations of the activity ,expecting exchanges be-tween colleagues with the same interest .%从资源、经济和国家安全等角度考虑,中国矿业企业“走出去”进行海外并购确实是大势所趋。数据显示,近几年中国矿业企业海外并购的步伐加快,但总的来看成功的案例不多。通过对近几年中国矿业企业海外并购的案例分析和亲身实践,全面梳理总结了海外并购的主要风险、决定因素和应对策略,旨在与同领域有志之士共同学习、交流和研讨。

  2. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  3. Is export orientation a major motivator for the adoption of food safety systems in the Turkish dried fig firms?

    Directory of Open Access Journals (Sweden)

    Ferit Cobanoglu

    2012-04-01

    Full Text Available Food safety management systems (FSMSs and the scrutinisation of the food safety practices that are intended for adoption on the firm level both offer strategic value to the dried fig sector. This study aims to prove the hypothesis that export orientation is a major motivating force for the adoption of food safety systems in the Turkish dried fig firms. Data were obtained from 91 dried fig firms located in Aydin, Turkey. Interviews were carried out with firms’ managers/owners using a face-to-face questionnaire designed from May to August of 2010. While 36.3 percent of the interviewed firms had adopted one or more systems, the rest had no certification. A binomial logistic econometric model was employed. The parameters that influenced this decision included contractual agreements with other firms, implementation of good practices by the dried fig farmers, export orientation and cost-benefit ratio. Interestingly, the rest of the indicators employed had no statistically significant effect on adoption behaviour. This paper focusses on the export orientation parameter directly in order to test the validity of the main research hypothesis. The estimated marginal effect suggests that when dried fig firms are export-oriented, the probability that these firms will adopt food safety systems goes up by 39.5 percent. This rate was the first range observed among all the marginal probability values obtained and thus verified the hypothesis that export orientation is a major motivator for the adoption of food safety systems in the Turkish dried fig firms.

  4. Phenolic Profile and Antioxidant Capacity of Ten Dry Red Wines from Two Major Wine-producing Regions in China

    Directory of Open Access Journals (Sweden)

    Feng-mei Zhu

    2014-03-01

    Full Text Available Ten dry red wines, produced two major wine-producing regions from China-Changli in Hebei Province and Yantai in Shandong Province, were examined in this study. The antioxidant activities of wines were measured by different analytical methods: 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH radical scavenging activity, 2, 2-azino-di-(3-ethylbenzothialozine-sulphonic acid (ABTS radical scavenging activity and Ferric Reducing Antioxidant Power (FRAP. Furthermore, total phenols, total flavonoids and seven individual phenolic compounds (Gallic acid; Catechin; Chlorogenic acid; Caffeic acid; Ferulic acid; Rutin and Morin of wines were also determined. The results showed that sample 9 (College dry red wine, Cabernet Sauvignon, 2011 contained the highest total phenol content, up to 2131 mg/L; sample 7 (Great Wall dry red wine, Cabernet Sauvignon, Yantai contained the highest total flavonoids, up to 1282 mg/L. Seven individual phenolics in wine samples were detected by Reverse Phase High Performance Liquid Chromatography (RP-HPLC. Different types of dry red wine polyphenols on DPPH scavenging rate from 78.88 to 98.55%, the highest FRAP scavenging activity was up to 222.66 &mumol/L, the lowest was 189.51 &mumol/L, different types of wine polyphenols have high ABTS scavenging activity. The current findings will provide useful information for evaluating the wine quality and for educating consumers to choose specific dry wine for specific health-promoting effects.

  5. Diffuse radio emission in MACS J0025.4$-$1222: the effect of a major merger on bulk separation of ICM components

    CERN Document Server

    Riseley, C J; Wise, M W; Clarke, A O

    2016-01-01

    Mergers of galaxy clusters are among the most energetic events in the Universe. These events have significant impact on the intra-cluster medium, depositing vast amounts of energy - often in the form of shocks - as well as heavily influencing the properties of the constituent galaxy population. Many clusters have been shown to host large-scale diffuse radio emission, known variously as radio haloes and relics. These sources arise as a result of electron (re-)acceleration in cluster-scale magnetic fields, although the processes by which this occurs are still poorly understood. We present new, deep radio observations of the high-redshift galaxy cluster MACS J0025.4$-$1222, taken with the GMRT at 325 MHz, as well as new analysis of all archival $Chandra$ X-ray observations. We aim to investigate the potential of diffuse radio emission and categorise the radio population of this cluster, which has only been covered previously by shallow radio surveys. We produce low-resolution maps of MACS J0025.4$-$1222 through ...

  6. Interaction-Triggered Star Formation in Distant Galaxies and the Role of Mergers in Galaxy Evolution

    CERN Document Server

    Lin, Lihwai

    2009-01-01

    The evolution of galaxy merger rates and its impact on galaxy properties have been studied intensively over the last decade. It becomes clear now that various types of mergers, i.e. gas-rich (wet), gas-poor (dry), or mixed mergers, affect the merger products in different ways. The epoch when each type of merger dominates also differs. In this talk, I review the recent progress on the measurements of galaxy merger rates out to z ~ 3 and the level of interaction-triggered star formation using large samples from various redshift surveys. These results provide insights to the importance of mergers in the mass assembly history of galaxies and in the evolution of galaxy properties. I also present new results in characterizing the environment of galaxy mergers, and discuss their implications in the built up of red-sequence galaxies.

  7. The Impacts of Business Risks on Mergers and Acquisitions

    OpenAIRE

    Shen, Rong

    2007-01-01

    Mergers and acquisition (M&As) are one of the most important strategies of corporate expansion and growth, also known as an external capital investment. M&As are normally create value to shareholders and corporations. The high investment returns of M&As means the high business risks. However, the practical evidences indicate that roughly half merger movements fail, based on the shareholder maximization perspective. There are four major business risks may challenge the success of merger, which...

  8. Mergers in Bidding Markets

    NARCIS (Netherlands)

    M.C.W. Janssen (Maarten); V.A. Karamychev (Vladimir)

    2013-01-01

    textabstractWe analyze the effects of mergers in first-price sealed-bid auctions on bidders' equilibrium bidding functions and on revenue. We also study the incentives of bidders to merge given the private information they have. We develop two models, depending on how after-merger valuations are cre

  9. Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Risberg, Annette

    , employee experiences and communication. Mergers and acquisitions remain one of the most common forms of growth, yet they present considerable challenges for the companies and management involved. The effects on stakeholders, including shareholders, managers and employees, must be considered as well......Introduction to the study of mergers and acquisitions. This book provides an understanding of the mergers and acquisitions process, how and why they occur, and also the broader implications for organizations. It presents issues including motives and planning, partner selection, integration...... by editorial commentaries and reflects the important organizational and behavioural aspects which have often been ignored in the past. By providing this in-depth understanding of the mergers and acquisitions process, the reader understands not only how and why mergers and acquisitions occur, but also...

  10. Financial Synergy in Mergers and Acquisitions in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Basmah Al Qudaiby (Basmah, A. Q.,

    2013-11-01

    Full Text Available Businesses today consider mergers and acquisitions a new strategy for their company’s growth. Companies aim to grow through sales’ increase, assets purchase, profits’ accumulation and market share gains. The better way for achieving these targets is by getting into either a Merger or an Acquisition. As a matter of fact, growth through mergers and acquisitions has been a critical part of the success of many companies operating in the new economy. Mergers and Acquisitions are an important factor in building up market capitalization. Based on three detailed and in depth structured interviews with major Saudi Arabian banks it has been found that, Mergers motivated by economies of scale should be approached cautiously. Companies should also approach vertical mergers cautiously because it is often difficult to gain synergy through a vertical merger and firms should also seek out mergers which allow the firm to acquire specialized knowledge. It has also been found that the firms should look for mergers that increase market power and avoid unrelated or conglomerate mergers.

  11. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  12. Diffuse radio emission in MACS J0025.4-1222: the effect of a major merger on bulk separation of ICM components

    Science.gov (United States)

    Riseley, C. J.; Scaife, A. M. M.; Wise, M. W.; Clarke, A. O.

    2017-01-01

    Context. Mergers of galaxy clusters are among the most energetic events in the Universe. These events have significant impact on the intra-cluster medium, depositing vast amounts of energy, often in the form of shocks, as well as heavily influencing the properties of the constituent galaxy population. Many clusters have been shown to host large-scale diffuse radio emission, known variously as radio haloes and relics. These sources arise as a result of electron (re-)acceleration in cluster-scale magnetic fields, although the processes by which this occurs are still poorly understood. Aims: We present new, deep radio observations of the high-redshift galaxy cluster MACS J0025.4-1222, taken with the Giant Metrewave Radio Telescope (GMRT) at 325 MHz, as well as a new analysis of all archival Chandra X-ray observations. We aim to investigate the potential of diffuse radio emission and categorise the radio population of this cluster, which has only been covered previously by shallow radio surveys. Methods: We produced low-resolution maps of MACS J0025.4-1222 through a combination of uv-tapering and subtracting the compact source population. Radial surface brightness and mass profiles were derived from the Chandra data. We also derived a 2D map of the intracluster medium temperature. Results: For the first time, two sources of diffuse radio emission are detected in MACS J0025.4-1222, on linear scales of several hundred kpc. Given the redshift of the cluster and the assumed cosmology, these sources appear to be consistent with established trends in power scaling relations for radio relics. The X-ray temperature map presents evidence of an asymmetric temperature profile and tentative identification of a temperature jump associated with one relic. Conclusions: We classify the pair of diffuse radio sources in this cluster as a pair of radio relics, given their consistency with scaling relations, location toward the cluster outskirts, and the available X-ray data.

  13. MERGER ACCOUTING FOR COMPANIES

    Directory of Open Access Journals (Sweden)

    SUCIU GHEORGHE

    2014-05-01

    Full Text Available Companies, especially nowadays, are characterized through great mobility, fast circulation of capital, occurring in their chase for profit. In this context, companies look for alliances, economical and political assistance. These objectives can materialize through merging of companies. The merger can be internal (between Romanian companies or transboundary, which includes foreign companies. In order to correctly reflect these events, the merger operations must be regulated and must respect national and international regulations. One important request concerning the merger operations is that the accounting values of the assets, debts and ownership equity must be brought to the present financial value.

  14. Dry Climate as Major Factor Controlling Formation of Hydrated Sulfate Minerals in Valles Marineris on Mars

    Science.gov (United States)

    Szynkiewicz, A.

    2016-12-01

    In this study, a model for the formation of hydrated sulfate salts (Mg-Ca-Na sulfates) in the Rio Puerco watershed of New Mexico, a terrestrial analog site from the semi-arid Southwest U.S., was used to assess the origin and climate condition that may have controlled deposition of hydrated sulfates in Valles Marineris on Mars. In this analog site, the surface accumulation of sulfate minerals along canyon walls, slopes and valley surfaces closely resemble occurrences of hydrated sulfates in Valles Marineris on Mars. Significant surface accumulations of Mg-Ca-Na sulfates are a result of prevailing semiarid conditions and a short-lived hydrological cycle that mobilizes sulfur present in the bedrock as sulfides, sulfate minerals, and atmospheric deposition. Repeating cycles of salt dissolution and re-precipitation appear to be the underpinning processes that serve to transport sulfate from bedrock to sulfate salts (e.g., efflorescences) and into surface water. This process occurs in the shallow surface environment and is not accompanied by deep groundwater flow because of prevailing dry conditions and low annual precipitation. Generally, close resemblance of surface occurrence and mineralogical composition of sulfate salts between the studied terrestrial analog and Valles Marineris suggest that a similar sulfate cycle, involving limited water activity during formation of hydrated sulfates, was once present in Valles Marineris. Measured as efflorescence, the distributed surface mass of hydrated sulfates in Valles Marineris is relatively small (4 to 42%) when compared to terrestrial settings with higher surface accumulation of sulfate minerals such as the White Sands gypsum dune field. Under semi-arid conditions similar to the studied analog in the Rio Pueurco watershed, it would take only 100 to 1,000 years to activate an equivalent flux of aqueous sulfate in Valles Marineris, when comparing terrestrial annual sulfate fluxes from the Rio Puerco watershed with the amount

  15. Mulga, a major tropical dry open forest of Australia: recent insights to carbon and water fluxes

    Science.gov (United States)

    Eamus, Derek; Huete, Alfredo; Cleverly, James; Nolan, Rachael H.; Ma, Xuanlong; Tarin, Tonantzin; Santini, Nadia S.

    2016-12-01

    Mulga, comprised of a complex of closely related Acacia spp., grades from a low open forest to tall shrublands in tropical and sub-tropical arid and semi-arid regions of Australia and experiences warm-to-hot annual temperatures and a pronounced dry season. This short synthesis of current knowledge briefly outlines the causes of the extreme variability in rainfall characteristic of much of central Australia, and then discusses the patterns and drivers of variability in carbon and water fluxes of a central Australian low open Mulga forest. Variation in phenology and the impact of differences in the amount and timing of precipitation on vegetation function are then discussed. We use field observations, with particular emphasis on eddy covariance data, coupled with modelling and remote sensing products to interpret inter-seasonal and inter-annual patterns in the behaviour of this ecosystem. We show that Mulga can vary between periods of near carbon neutrality to periods of being a significant sink or source for carbon, depending on both the amount and timing of rainfall. Further, we demonstrate that Mulga contributed significantly to the 2011 global land sink anomaly, a result ascribed to the exceptional rainfall of 2010/2011. Finally, we compare and contrast the hydraulic traits of three tree species growing close to the Mulga and show how each species uses different combinations of trait strategies (for example, sapwood density, xylem vessel implosion resistance, phenological guild, access to groundwater and Huber value) to co-exist in this semi-arid environment. Understanding the inter-annual variability in functional behaviour of this important arid-zone biome and mechanisms underlying species co-existence will increase our ability to predict trajectories of carbon and water balances for future changing climates.

  16. Galaxy Pairs in COSMOS -- Merger Rate Evolution Since z=1

    CERN Document Server

    Xu, C Kevin; Scoville, N; Capak, P; Drory, N; Gao, Y

    2011-01-01

    We present results of a statistical study of the cosmic evolution of mass dependent major-merger rate since z=1. A stellar mass limited sample of major-merger pairs (CPAIR sample) was selected from the archive of the COSMOS survey, based on photo-z and visual inspections of the HST-ACS images. Pair fractions at different redshifts derived using the CPAIR sample and a local K-band selected pair sample show no significant variations with stellar mass. The pair fraction exhibits moderately strong cosmic evolution, with the best-fitting evolutionary index m=2.2+-0.2. The best-fitting function for the merger rate implies that galaxies with stellar mass between 1E+10 -- 3E+11 M_sun have undergone 0.4 -- 1.2 major-mergers since z=1. Our results show that, for massive galaxies at z<1, major mergers involving star forming galaxies (i.e. wet and mixed mergers) can account for the formation of both ellipticals and red quiescent galaxies (RQGs). On the other hand, major mergers cannot be responsible for the formation ...

  17. Performance Assessment of Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan; Moini, Hamid

    2012-01-01

    Corporate mergers and acquisitions (M&As) have been increasing popular during these decades. However, a majority of research show failure rate (40% - 80%) has not significantly changed. This “success paradox” triggers us to reflect on performance assessment of M&As: how the performance of M...

  18. School District Mergers: What One District Learned

    Science.gov (United States)

    Kingston, Kathleen

    2009-01-01

    Throughout the planning process for a school district merger in a northwestern Pennsylvania school district, effective communication proved to be a challenge. Formed in 1932, this school district of approximately 1400 students was part of a utopian community; one established by a transportation system's corporation that was a major industrial…

  19. RF merger and acquisition market

    Directory of Open Access Journals (Sweden)

    Evgeniya V. Vidishcheva

    2011-04-01

    Full Text Available The article gives brief characteristic of merger and acquisition market situation in Russia, brings in overview of bargains in 2009–2010. Russian merger and acquisition market is in early stage of development.

  20. RF merger and acquisition market

    OpenAIRE

    Evgeniya V. Vidishcheva; Merab S. Sichinava; Marina V. Kogan

    2011-01-01

    The article gives brief characteristic of merger and acquisition market situation in Russia, brings in overview of bargains in 2009–2010. Russian merger and acquisition market is in early stage of development.

  1. Nonmarket strategy for merger reviews

    NARCIS (Netherlands)

    Clougherty, J.A.

    2003-01-01

    Mergers and acquisitions can involve a significant review by antitrust authorities; however, neither the business strategy not the corporate political strategy literature has fully explored the antitrust dimensions of merger activity. This article considers the ability of corporate political activit

  2. ROLE OF INTERNATIONAL MERGERS AND ACQUISITIONS IN CORPORATE INTEGRATION

    Directory of Open Access Journals (Sweden)

    Lucia P. BLĂJUȚ

    2015-04-01

    Full Text Available This paper highlights the role of international mergers and acquisitions in corporate integration. The factors that stimulate mergers and acquisitions activities bring real changes in the world economy. Mergers and acquisitions are a form of expansion: mergers can take place either as a statutory merger or consolidation and minority, majority or full acquisitions dominate the international market. It is very important to not confuse the meaning of the two terms. Multinational companies are forced by the competitive environment to adopt new strategies to penetrate a particular market and decrease the position of competition on global market or to counteract competitor action on the other market. Cross-border M and A is functionally classified in horizontal, vertical, concentric and conglomerate. The balance between these types of M and A has been changing over time and the distinction among these four categories is not always clear-cut.

  3. The minor role of gas-rich major mergers in the rise of intermediate-mass early types at z <~ 1

    CERN Document Server

    López-Sanjuan, C; Pérez-González, P G; Barro, G; García-Dabó, C E; Gallego, J; Zamorano, J

    2009-01-01

    We study the evolution of galaxy structure since z ~ 1 to the present. From a GOODS-S multi-band catalog we define (blue) luminosity- and mass-weighted samples, limited by M_B = 10^10 M_Sun, comprising 1122 and 987 galaxies, respectively. We extract early-type (E/S0/Sa) and late-type (Sb-Irr) subsamples by their position in the concentration-asymmetry plane, in which galaxies exhibit a clear bimodality. We find that the early-type fraction, f_ET, rises with cosmic time, with a corresponding decrease in the late-type fraction, f_LT, in both luminosity- and mass-selected samples. However, the evolution of the comoving number density is very different: the decrease in the total number density of M_B = 10^10 M_Sun galaxies in the same redshift range is due to the evolution of early types. This suggests that we need a structural transformation between late-type galaxies that form stars actively and early-type galaxies in which the stellar mass is located. Comparing the observed evolution with the gas-rich major me...

  4. Merger Bank Bermasalah di Indonesia

    Directory of Open Access Journals (Sweden)

    Titik Indrawati

    2001-09-01

    Full Text Available The basic of problem for direction and senior manager bank is how to maximalize the value of share owner. It focus on how to make value by merger, how to get the value of bank target, and how to consider the nonfinancial influence the value by merger. The objective of the research wrap up the traveling’s merger and acquisition phenomenon in Indonesia. That objective are more focused on how merger can increase value, how to decide Bank’s value and the non financial parameter that can affact the sucsess of the merger comp. It’s concluded that Indonesian society see Bank merger as a final action to save a Bank from Bankcoruptcy. In negotiating the merger agreement, buyer and seller must consider the financial & non financial parameters.

  5. CHANDRA OBSERVATIONS OF GALAXY ZOO MERGERS: FREQUENCY OF BINARY ACTIVE NUCLEI IN MASSIVE MERGERS

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Stacy H. [Observational Cosmology Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Schawinski, Kevin; Urry, C. Megan; Bonning, Erin W. [Department of Physics, Yale University, New Haven, CT 06511 (United States); Darg, Dan W.; Kaviraj, Sugata; Lintott, Chris J. [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Oh, Kyuseok [Department of Astronomy, Yonsei University, Seoul 120-749 (Korea, Republic of); Cardamone, Carolin N. [Harriet W. Sheridan Center for Teaching and Learning, Brown University, P.O. Box 1912, Providence, RI 02912 (United States); Keel, William C. [Department of Physics and Astronomy, 206 Gallalee Hall, 514 University Boulevard, University of Alabama, Tuscaloosa, AL 35487-034 (United States); Simmons, Brooke D. [Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520 (United States); Treister, Ezequiel, E-mail: stacy.h.teng@nasa.gov [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

    2012-07-10

    We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 10{sup 11} M{sub Sun} that already have optical active galactic nucleus (AGN) signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N{sub H} {approx}< 1.1 Multiplication-Sign 10{sup 22} cm{sup -2}) X-ray nuclei are relatively common (8/12), but the detections are too faint (<40 counts per nucleus; f{sub 2-10keV} {approx}< 1.2 Multiplication-Sign 10{sup -13} erg s{sup -1} cm{sup -2}) to reliably separate starburst and nuclear activity as the origin of the X-ray emission. Only one merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGNs in these mergers are rare (0%-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  6. Chandra Observations of Galaxy Zoo Mergers: Frequency of Binary Active Nuclei in Massive Mergers

    Science.gov (United States)

    Teng, Stacy H.; Schawinski, Kevin; Urry, C. Megan; Darg, Dan W.; Kaviraj, Sugata; Oh, Kyuseok; Bonning, Erin W.; Cardamone, Carolin N.; Keel, William C.; Lintott, Chris J.; Simmons, Brooke D.; Treister, Ezequiel

    2012-01-01

    We present the results from a Chandra pilot study of 12 massive galaxy mergers selected from Galaxy Zoo. The sample includes major mergers down to a host galaxy mass of 1011 M that already have optical AGN signatures in at least one of the progenitors. We find that the coincidences of optically selected active nuclei with mildly obscured (N(sub H) approx < 1.1 10(exp 22)/sq cm) X-ray nuclei are relatively common (8/12), but the detections are too faint (< 40 counts per nucleus; (sub -10) keV approx < 1.2 10(exp -13) erg/s/sq cm) to reliably separate starburst and nuclear activity as the origin of the X-ray emission. Only one merger is found to have confirmed binary X-ray nuclei, though the X-ray emission from its southern nucleus could be due solely to star formation. Thus, the occurrences of binary AGN in these mergers are rare (0-8%), unless most merger-induced active nuclei are very heavily obscured or Compton thick.

  7. Late-stage galaxy mergers in COSMOS to z~1

    CERN Document Server

    Lackner, C N; Salvato, M; Kampczyk, P; Kartaltepe, J S; Sanders, D; Capak, P; Civano, F; Ilbert, O; Jahnke, K; Koekemoer, A M; Lee, N; Fevre, O Le; Liu, C T; Scoville, N; Sheth, K; Toft, S

    2014-01-01

    The role of major mergers in galaxy and black hole formation is not well constrained. To help address this, we develop an automated method to identify late-stage galaxy mergers before coalescence of the galactic cores. The resulting sample of mergers is distinct from those obtained using pair-finding and morphological indicators. Our method relies on median-filtering of high-resolution images in order to distinguish two concentrated galaxy nuclei at small separations. Using mock images, we derive statistical contamination and incompleteness corrections for the fraction of late-stage mergers. We apply our new method to a magnitude-limited (I 10.6$ and $0.25 < z \\leq 1.00$, we find ~5% of systems are late-stage mergers with separations between 2.2 and 8 kpc. Correcting for incompleteness and contamination, the fractional merger rate increases strongly with redshift as $(1+z)^{3.8\\pm0.9}$, in agreement with earlier studies and with dark matter halo merger rates. Separating the sample into star-forming and qu...

  8. Business cycle modelling - The case of mergers and acquisitions

    OpenAIRE

    Güzey, Yıldız Yılmaz; Taşseven, Özlem

    2012-01-01

    Business cycle models involve exploiting movements of the economy to gain competitive advantage over rivals. Business cycles are applicable to mergers and acquisitions (M&A) which occur in waves. Econometricians have attempted to model these waves. The paper demonstrates that, with respect to each of several major stylized facts about business cycles, the seasonal cycle displays the same characteristics as the business cycle. Therefore the patterns in merger and acquisitions measured as merge...

  9. Binary Neutron Star Mergers

    Directory of Open Access Journals (Sweden)

    Joshua A. Faber

    2012-07-01

    Full Text Available We review the current status of studies of the coalescence of binary neutron star systems. We begin with a discussion of the formation channels of merging binaries and we discuss the most recent theoretical predictions for merger rates. Next, we turn to the quasi-equilibrium formalisms that are used to study binaries prior to the merger phase and to generate initial data for fully dynamical simulations. The quasi-equilibrium approximation has played a key role in developing our understanding of the physics of binary coalescence and, in particular, of the orbital instability processes that can drive binaries to merger at the end of their lifetimes. We then turn to the numerical techniques used in dynamical simulations, including relativistic formalisms, (magneto-hydrodynamics, gravitational-wave extraction techniques, and nuclear microphysics treatments. This is followed by a summary of the simulations performed across the field to date, including the most recent results from both fully relativistic and microphysically detailed simulations. Finally, we discuss the likely directions for the field as we transition from the first to the second generation of gravitational-wave interferometers and while supercomputers reach the petascale frontier.

  10. Bank Mergers, Competition and Liquidity

    OpenAIRE

    Carletti, Elena; Hartmann, Philipp; Spagnolo, Giancarlo

    2004-01-01

    We model the impact of bank mergers on loan competition, reserve holdings and aggregate liquidity. A merger changes the distribution of liquidity shocks and creates an internal money market, leading to financial cost efficiencies and more precise estimates of liquidity needs. The merged banks may increase their reserve holdings through an internalization effect or decrease them because of a diversification effect. The merger also affects loan market competition, which in turn modifies the dis...

  11. Field guide to the major organisms and processes building reefs and islands of the Dry Tortugas: the Carnegie Dry Tortugas Laboratory Centennial Celebration (1905-2005)

    Science.gov (United States)

    Shinn, Eugene A.; Jaap, Walter C.

    2005-01-01

    This guide to the geology and biology of the Dry Tortugas is divided into four sections: 1) geologic and anthropogenic features you will pass on your trip to and from the Tortugas, 2) a summary of items of Tortugas geologic, historic, and human interest and what you will experience at Loggerhead Key while walking and snorkeling, 3) a summary of recent coral-monitoring results, and 4) an Appendix with tributes to some of the significant research accomplishments of researchers at the laboratory between 1905 and 1939.

  12. The effects of union mergers and internal restructuring:

    DEFF Research Database (Denmark)

    Navrbjerg, Steen Erik; Larsen, Trine Pernille

    2016-01-01

    Trade union mergers and restructuring are often seen as strategy for union revitalisation and renewal and have been ongoing in the majority of European trade unions. This paper explores how recent union mergers and internal restructuring has affected unions service provision, union democracy...... and interest representation. This is analysed drawing on longitudinal data from two Danish shop steward surveys conducted in 1998 and 2010, comparing shop stewards in merged and non-merged unions respectively. The main results are that although it could be expected that union mergers and internal restructuring......, where union size and less so the union’s recent merger and restructuring history appears to affect shop stewards’ relations with their unions....

  13. Welfare standards in hospital mergers.

    Science.gov (United States)

    Katona, Katalin; Canoy, Marcel

    2013-08-01

    There is a broad literature on the consequences of applying different welfare standards in merger control. Total welfare is usually defined as the sum of consumer and provider surplus, i.e., potential external effects are not considered. The general result is then that consumer welfare is a more restrictive standard than total welfare, which is advantageous in certain situations. This relationship between the two standards is not necessarily true when the merger has significant external effects. We model mergers on hospital markets and allow for not-profit-maximizing behavior of providers and mandatory health insurance. Mandatory health insurance detaches the financial and consumption side of health care markets, and the concept consumer in merger control becomes non-evident. Patients not visiting the merging hospitals still are affected by price changes through their insurance premiums. External financial effects emerge on not directly affected consumers. We show that applying a restricted interpretation of consumer (neglecting externality) in health care merger control can reverse the relation between the two standards; consumer welfare standard can be weaker than total welfare. Consequently, applying the wrong standard can lead to both clearing socially undesirable and to blocking socially desirable mergers. The possible negative consequences of applying a simple consumer welfare standard in merger control can be even stronger when hospitals maximize quality and put less weight on financial considerations. We also investigate the implications of these results for the practice of merger control.

  14. Merger of Long Vortex Filaments

    CERN Document Server

    Khandekar, Akshay

    2012-01-01

    This fluid dynamics video demonstrates the merger of long vortex filaments is shown experimentally. Two counter-rotating vortices are generated using in a tank with very high aspect ratio. PIV demonstrates the merger of the vortices within a single orbit.

  15. Competition and Mergers among Nonprofits

    NARCIS (Netherlands)

    Prüfer, J.

    2007-01-01

    Should mergers among nonprofit organizations be regulated differently than mergers among for-profit firms? The relevant empirical literature is highly controversial, the theoretical literature is scarce. We analyze the question by modeling duopoly competition with quality-differentiated goods. We co

  16. Competition and Mergers among Nonprofits

    NARCIS (Netherlands)

    Prüfer, J.

    2007-01-01

    Should mergers among nonprofit organizations be regulated differently than mergers among for-profit firms? The relevant empirical literature is highly controversial, the theoretical literature is scarce. I analyze the question by modeling duopoly competition with quality-differentiated goods. I comp

  17. School Merger: A Stressful Challenge?

    Science.gov (United States)

    McHugh, Marie; Kyle, Margaret

    1993-01-01

    Increased pace of change and enhanced competition within British education, coupled with threatened or actual school mergers, have brought added pressures to the teaching profession. A study of 76 teachers from 5 Northern Ireland secondary schools that were threatened by merger, had merged, or had not merged revealed that those threatened by…

  18. 76 FR 37895 - Merger Applications

    Science.gov (United States)

    2011-06-28

    ... Office of Thrift Supervision Merger Applications AGENCY: Office of Thrift Supervision (OTS), Treasury... collection. Title of Proposal: Merger Applications. OMB Number: 1550-0016. Form Number: N/A. Description: No savings association may, without application to and approval by the OTS combine with any insured...

  19. Mixing in massive stellar mergers

    CERN Document Server

    Gaburov, E; Zwart, S Portegies

    2007-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynamic simulations in three dimensions. We present a computationally inexpensive method in which we approximate the merger process, including shock heating, hydrodynamic mixing and mass loss, with a simple algorithm which is based on conservation laws and a basic qualitative understanding of the hydrodynamics of stellar mergers. The algorithm is based on Archimedes' principle, which dictates the distribution of the fluid in stable equilibrium situation. We calibrate and apply the method to mergers of massive stars, as these are expected to occur in young and dense star clusters. We find that mergers between spectral type B stars ($\\sim$10\\msun) result in substantial mixing, whereas mergers between stars of different sp...

  20. Dry steam feed zones and silica scaling as major controls of total flow enthalpy at Cerro Prieto, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Beall, J.J. [Calpine Corp., Santa Rosa, CA (United States); Ledesma, A.P.; Dios Ocampo, J. de [Constructora y Perforadora Latina S.A., Baja California (Mexico)

    1997-12-31

    Enthalpy and chloride data for Cerro Prieto well fluids define a mixing line between original reservoir liquid (1,300-1,500 J/g, 9,000-11,000 ppm Cl) and superheated steam (2870 J/g, 0 ppm Cl). The mixing relationship establishes that dry steam feed zones contribute to the total fluid flow of many wells. Fluids produced from newly completed or worked over wells often show rapid movement in either direction along the enthalpy-chloride mixing line. The direction of movement along the enthalpy-chloride mixing line depends upon whether increased formation boiling (increasing the dry steam flow to the well) or silica scaling in the formation and on the surface of the well bore (which inhibits the flow of dry steam) is the dominant process.

  1. Hydrogen in hot subdwarfs formed by double helium white dwarf mergers

    CERN Document Server

    Hall, Philip D

    2016-01-01

    Isolated hot subdwarfs might be formed by the merging of two helium-core white dwarfs. Before merging, helium-core white dwarfs have hydrogen-rich envelopes and some of this hydrogen may survive the merger. We calculate the mass of hydrogen that is present at the start of such mergers and, with the assumption that hydrogen is mixed throughout the disrupted white dwarf in the merger process, estimate how much can survive. We find a hydrogen mass of up to about $2 \\times 10^{-3}\\,\\mathrm{M}_{\\odot}$ in merger remnants. We make model merger remnants that include the hydrogen mass appropriate to their total mass and compare their atmospheric parameters with a sample of apparently isolated hot subdwarfs, hydrogen-rich sdBs. The majority of these stars can be explained as the remnants of double helium white dwarf mergers.

  2. When galaxy clusters collide : the impact of merger shocks on cluster gas and galaxy evolution

    NARCIS (Netherlands)

    Stroe, Andra

    2015-01-01

    Galaxy clusters mainly grow through mergers with other clusters and groups. Major mergers give rise to cluster-wide traveling shocks, which can be detected at radio wavelengths as relics: elongated, diffuse synchrotron emitting areas located at the periphery of merging clusters. The 'Sausage' cluste

  3. Mergers. Turn of the screw.

    Science.gov (United States)

    Gillett, S

    2000-04-01

    Managing the process of a merger with staff support and job counselling reduces stress. But the experience is not pain-free. The expectation that senior staff would be found other jobs in the NHS proved unrealistic. From a total staff of 6,000 there were 38 redundancies, of which 13 were voluntary. Early retirement and redundancy costs were higher than expected. Staff still show signs of distress a year after the merger took place.

  4. Generating merger trees for dark matter haloes: a comparison of methods

    Science.gov (United States)

    Jiang, Fangzhou; van den Bosch, Frank C.

    2014-05-01

    Halo merger trees describe the hierarchical assembly of dark matter haloes, and are the backbone for modelling galaxy formation and evolution. Merger trees constructed using Monte Carlo algorithms based on the extended Press-Schechter (EPS) formalism are complementary to using N-body simulations and have the advantage that they are not trammelled by limited numerical resolution and uncertainties in identifying and linking (sub)haloes. This paper compares multiple EPS-based merger tree algorithms to simulation results using four diagnostics: progenitor mass function, mass assembly history (MAH), merger rate per descendant halo and the unevolved subhalo mass function. Spherical collapse-based methods typically overpredict major-merger rates, whereas ellipsoidal collapse dramatically overpredicts the minor-merger rate for massive haloes. The only algorithm in our comparison that yields results in good agreement with simulations is that by Parkinson et al. (P08). We emphasize, though, that the simulation results used as benchmarks in testing the merger trees are hampered by significant uncertainties themselves: MAHs and merger rates from different studies easily disagree by 50 per cent, even when based on the same simulation. Given this status quo, the P08 merger trees can be considered as accurate as those extracted from simulations.

  5. Performance Assessment of Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan; Moini, Hamid

    2012-01-01

    Corporate mergers and acquisitions (M&As) have been increasing popular during these decades. However, a majority of research show failure rate (40% - 80%) has not significantly changed. This “success paradox” triggers us to reflect on performance assessment of M&As: how the performance of M...... on the performance measures and benchmarks adopted in M&A research field and the relevant empirical results. We find that the definitions of performance varied in terms of accounting, financial, operational and perceptual metrics. And performance assessment is sensitive to the definition of performance, methodology...

  6. Late-stage galaxy mergers in cosmos to z ∼ 1

    Energy Technology Data Exchange (ETDEWEB)

    Lackner, C. N.; Silverman, J. D. [Kavli IPMU (WPI), The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Salvato, M. [Max-Planck-Institut für extraterrestrische Physik, D-84571 Garching (Germany); Kampczyk, P. [Institute of Astronomy, Department of Physics, ETH Zürich, CH-8093 Zürich (Switzerland); Kartaltepe, J. S. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Sanders, D.; Lee, N. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Capak, P.; Scoville, N. [California Institute of Technology, Pasadena, CA 91125 (United States); Civano, F. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Halliday, C. [23, rue d’Yerres, F-91230 Montgeron (France); Ilbert, O.; Le Fèvre, O. [Aix Marseille Université, CNRS, LAM (Laboratoire dAstrophysique de Marseille), F-13388, Marseille (France); Jahnke, K. [Max-Planck-Institut für Astronomie, D-69117 Heidelberg (Germany); Koekemoer, A. M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Liu, C. T. [Astrophysical Observatory, CUNY, College of Staten Island, NY 10314 (United States); Sheth, K. [National Radio Astronomy Observatory/NAASC, Charlottesville, VA 22903 (United States); Toft, S., E-mail: claire.lackner@ipmu.jp [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Copenhagen, DK-2100 (Denmark)

    2014-12-01

    The role of major mergers in galaxy and black hole formation is not well-constrained. To help address this, we develop an automated method to identify late-stage galaxy mergers before coalescence of the galactic cores. The resulting sample of mergers is distinct from those obtained using pair-finding and morphological indicators. Our method relies on median-filtering of high-resolution images to distinguish two concentrated galaxy nuclei at small separations. This method does not rely on low surface brightness features to identify mergers, and is therefore reliable to high redshift. Using mock images, we derive statistical contamination and incompleteness corrections for the fraction of late-stage mergers. The mock images show that our method returns an uncontaminated (<10%) sample of mergers with projected separations between 2.2 and 8 kpc out to z∼1. We apply our new method to a magnitude-limited (m{sub FW} {sub 814}<23) sample of 44,164 galaxies from the COSMOS HST/ACS catalog. Using a mass-complete sample with logM{sub ∗}/M{sub ⊙}>10.6 and 0.25mergers. Correcting for incompleteness and contamination, the fractional merger rate increases strongly with redshift as r{sub merge}∝(1+z){sup 3.8±0.9}, in agreement both with earlier studies and with dark matter halo merger rates. Separating the sample into star-forming and quiescent galaxies shows that the merger rate for star-forming galaxies increases strongly with redshift, (1+z){sup 4.5±1.3}, while the merger rate for quiescent galaxies is consistent with no evolution, (1+z){sup 1.1±1.2}. The merger rate also becomes steeper with decreasing stellar mass. Limiting our sample to galaxies with spectroscopic redshifts from zCOSMOS, we find that the star formation rates and X-ray selected active galactic nucleus (AGN) activity in likely late-stage mergers are higher by factors of ∼2 relative to those of a control sample. Combining our sample with more

  7. Investigating the merger origin of Early-Type Galaxies using ultra-deep optical images

    CERN Document Server

    Duc, P -A; Alatalo, K; Blitz, L; Bois, M; Bournaud, F; Bureau, M; Cappellari, M; Cote, P; Davies, R L; Davis, T A; de Zeeuw, P T; Emsellem, E; Ferrarese, L; Ferriere, E; Gwyn, S; Khochfar, S; Krajnovic, D; Kuntschner, H; Lablanche, P -Y; MacArthur, L; McDermid, R M; Michel-Dansac, L; Morganti, R; Naab, T; Oosterloo, T; Sarzi, M; Scott, N; Serra, P; Weijmans, A; Young, L M

    2011-01-01

    The mass assembly of galaxies leaves various imprints on their surroundings, such as shells, streams and tidal tails. The frequency and properties of these fine structures depend on the mechanism driving the mass assembly: e.g. a monolithic collapse, rapid cold-gas accretion followed by violent disk instabilities, minor mergers or major dry / wet mergers. Therefore, by studying the outskirts of galaxies, one can learn about their main formation mechanism. I present here our on-going work to characterize the outskirts of Early-Type Galaxies (ETGs), which are powerful probes at low redshift of the hierarchical mass assembly of galaxies. This work relies on ultra-deep optical images obtained at CFHT with the wide-field of view MegaCam camera of field and cluster ETGs obtained as part of the Atlas-3D and NGVS projects. State of the art numerical simulations are used to interpret the data. The images reveal a wealth of unknown faint structures at levels as faint as 29 mag arcsec-2 in the g-band. Initial results fo...

  8. Radio Loud AGNs are Mergers

    CERN Document Server

    Chiaberge, Marco; Lotz, Jennifer; Norman, Colin

    2015-01-01

    We measure the merger fraction of Type 2 radio-loud and radio-quiet active galactic nuclei at z>1 using new samples. The objects have HST images taken with WFC3 in the IR channel. These samples are compared to the 3CR sample of radio galaxies at z>1 and to a sample of non-active galaxies. We also consider lower redshift radio galaxies with HST observations and previous generation instruments (NICMOS and WFPC2). The full sample spans an unprecedented range in both redshift and AGN luminosity. We perform statistical tests to determine whether the different samples are differently associated with mergers. We find that all (92%) radio-loud galaxies at z>1 are associated with recent or ongoing merger events. Among the radio-loud population there is no evidence for any dependence of the merger fraction on either redshift or AGN power. For the matched radio-quiet samples, only 38% are merging systems. The merger fraction for the sample of non-active galaxies at z>1 is indistinguishable from radio-quiet objects. This...

  9. Topics in Finance: Part VIII--Mergers & Acquisitions

    Science.gov (United States)

    Laux, Judy

    2012-01-01

    In this series, three key axioms--stockholder wealth maximization, the risk-return tradeoff, and agency conflicts--are applied to the major topics in financial management. The current article looks at mergers and acquisitions, reviewing the presumed motivations, the ethical challenges, and the literature dedicated to this financial activity.

  10. The impact of mergers on pharmaceutical R&D.

    Science.gov (United States)

    LaMattina, John L

    2011-08-01

    Mergers and acquisitions in the pharmaceutical industry have substantially reduced the number of major companies over the past 15 years. The short-term business rationale for this extensive consolidation might have been reasonable, but at what cost to research and development productivity?

  11. Galaxy pairs as a probe for mergers at z ~ 2

    DEFF Research Database (Denmark)

    Man, A.W.S.; Zirm, Andrew Wasmuth; Toft, Sune

    2011-01-01

    In this work I investigate the redshift evolution of pair fraction of a sample of 196 massive galaxies from z = 0 to 3, selected from the COSMOS field. We find that on average a massive galaxy undergoes ~ 1.1 \\pm 0.5 major merger since z = 3. I will review the current limitations of using the pair...

  12. The Scanfin Merger: Managing Organisational Change (Case C)

    DEFF Research Database (Denmark)

    Smith, Pernille; Carugati, Andrea; Giangreco, Antonio

    This is the third of a four-case series (408-115-1, 908-025-1, 308-343-1 and 608-037-1). This case is about resistance to organisational change in relation to a merger. The case describes a major organisational change in a newly established department, which has been instituted to speed up the in...

  13. Trade Union Mergers: A Survey of the Literature.

    Science.gov (United States)

    Michelson, Grant

    2000-01-01

    Examines trade union mergers highlighting merger forms, merger motivation, role played by union officers, and merger waves. Discusses the consequences of mergers on members and union performance and concludes that union merger activity has had little impact. (Contains 74 references.) (JOW)

  14. Merger Strategy, Cross-Cultural Involvement, and Polyphony

    DEFF Research Database (Denmark)

    Svane, Marita; Boje, David

    2014-01-01

    and an upcoming crises, but these signs were not taken seriously. Learning to understand power relations has become a major issue to the manager. After the split, the fights in the living story arena are continuing and has now expanded as the customers are beginning to take part in the storytelling. The web...... it is the birth to life threatening death of a merger. Grander narrative (Lyotard, 1968) requires living story to be a proper "imitation of an action that is complete in itself, as a whole of some magnitude... Now a whole is that which has beginning, middle, and end" the definition of coherent narrative...... of customers and many competitors. The industry is therefore characterised by a high degree of mergers and acquisitions. Despite the strategic advantages the idea of the merger was not equally attractive to both of the organisations. They had a history of being competitors with a good deal of hostility. One...

  15. Connections between galaxy mergers and Starburst: evidence from local Universe

    CERN Document Server

    Luo, Wentao; Zhang, Youcai

    2014-01-01

    Major mergers and interactions between gas-rich galaxies with comparable masses are thought to be the main triggers of starburst. In this work, we study, for a large stellar mass range, the interaction rate of the starburst galaxies in the local universe. We focus independently on central and satellite star forming galaxies extracted from the Sloan Digital Sky Survey. Here the starburst galaxies are selected in the star formation rate (SFR) stellar mass plane with SFR five times larger than the median value found for "star forming" galaxies of the same stellar mass. Through visual inspection of their images together with close companions determined using spectroscopic redshifts, we find that ~50% of the "starburst" populations show evident merger features, i.e., tidal tails, bridges between galaxies, double cores and close companions. In contrast, in the control sample we selected from the normal star forming galaxies, only ~19% of galaxies are associated with evident mergers. The interaction rates may increa...

  16. University Mergers in Finland: Mediating Global Competition

    Science.gov (United States)

    Välimaa, Jussi; Aittola, Helena; Ursin, Jani

    2014-01-01

    University mergers have become a common strategy for increasing global competitiveness. In this chapter, the authors analyze the implementation of mergers in Finnish universities from the perspective of social justice as conceived within Finland and other Nordic countries.

  17. University Mergers in Finland: Mediating Global Competition

    Science.gov (United States)

    Välimaa, Jussi; Aittola, Helena; Ursin, Jani

    2014-01-01

    University mergers have become a common strategy for increasing global competitiveness. In this chapter, the authors analyze the implementation of mergers in Finnish universities from the perspective of social justice as conceived within Finland and other Nordic countries.

  18. Dynamics of compact object mergers

    Science.gov (United States)

    Bauswein, Andreas

    2017-01-01

    Advanced LIGO's first detection of gravitational waves (GWs) from merging black holes has opened a new window to the Universe. The observation of neutron-star (NS) mergers is imminent and promises far-reaching implications. We will describe the dynamics of NS mergers focusing on the postmerger dynamics. In particular, we will point out the implications for matter ejection from these events. Neutron-rich outflows from NS mergers are invoked to explain the still mysterious origin of heavy elements which are formed through the rapid neutron-capture process. The nuclear decays in these ejecta power electromagnetic counterparts which are potentially observable. We will describe the properties of these transients within a multi-messenger picture including in particular information that can be revealed from simultaneous GW detections.

  19. Generating Merger Trees for Dark Matter Haloes: A Comparison of Methods

    CERN Document Server

    Jiang, Fangzhou

    2013-01-01

    Halo merger trees describe the hierarchical mass assembly of dark matter haloes, and are the backbone for modeling galaxy formation and evolution. Merger trees constructed using Monte Carlo algorithms based on the extended Press-Schechter (EPS) formalism are complementary to those extracted from N-body simulations, and have the advantage that they are not trammeled by limited numerical resolution and uncertainties in identifying (sub)haloes and linking them between snapshots. This paper compares multiple EPS-based merger tree algorithms to simulation results using four diagnostics: progenitor mass function (PMF), mass assembly history (MAH), merger rate per descendant halo, and the unevolved subhalo mass function (USMF). In general, algorithms based on spherical collapse yield major-merger rates that are too high by a factor of two, resulting in MAHs that are systematically offset. Assuming ellipsoidal collapse solves most of these issues, but the particular algorithm investigated here that incorporates ellip...

  20. Mergers of black-hole binaries with aligned spins: Waveform characteristics

    CERN Document Server

    Kelly, Bernard J; Boggs, William D; McWilliams, Sean T; Centrella, Joan

    2011-01-01

    We conduct a descriptive analysis of the multipolar structure of gravitational-radiation waveforms from equal-mass aligned-spin mergers, following an approach first presented in the complementary context of nonspinning black holes of varying mass ratio [Baker et al., Phys. Rev. D 78:044046 (2008)]. We find that, as with the nonspinning mergers, the dominant waveform mode phases evolve together in lock-step through inspiral and merger, supporting the previous waveform description in terms of an adiabatically rigid rotator driving gravitational-wave emission -- an implicit rotating source (IRS). We further apply the late-time merger-ringdown model for the rotational frequency introduced in Baker et al. (2008), along with an improved amplitude model appropriate for the dominant (2,+/- 2) modes. This provides a quantitative description of the merger-ringdown waveforms, and suggests that the major features of these waveforms can be described with reference only to the intrinsic parameters associated with the state...

  1. The Role of Dissipation in the Scaling Relations of Cosmological Merger Remnants

    CERN Document Server

    Covington, M D; Porter, L A; Croton, D J; Somerville, R S; Dekel, A

    2011-01-01

    There are strong correlations between the three structural properties of elliptical galaxies -- stellar mass, velocity dispersion and size -- in the form of a tight "fundamental plane" and a "scaling relation" between each pair. Major mergers of disk galaxies are assumed to be a mechanism for producing ellipticals, but earlier studies of mergers encountered apparent difficulties in reproducing the observed slope and scatter of the size-mass relation. We study the scaling relations of merger remnants using progenitor properties from two semi-analytic galaxy formation models (SAM). We apply a simple merger model that includes gas dissipation and star formation based on theoretical considerations and simulations. Without tuning the merger model parameters for each SAM, the results roughly match the slope and scatter in the observed scaling relations and their evolution in the redshift range $z=0-3$. Within this model, the observed scaling relations, including the tilt of the fundamental plane relative to the vir...

  2. Atmospheric particle dry deposition of major ions to the South Atlantic coastal area observed at Baía de Todos os Santos, Brazil

    Directory of Open Access Journals (Sweden)

    STELYUS L. MKOMA

    2014-03-01

    Full Text Available The coastal atmosphere adjacent to large urban areas can be strongly affected by the emission of air pollutants, among them, major ions species. In this study, the chemical composition and sources of carboxylates and other water-soluble ions in fine and coarse aerosols as well as estimates of particle dry deposition fluxes were studied at a tropical coastal site affected by an urban environment. The mean concentrations of the total carboxylates were 78 ng m–3 in fine fraction and 81 ng m–3 in coarse fraction of particulate matter (PM. The corresponding values for the total inorganic ions were 2143 ng m–3 and 4880 ng m–3 respectively. Main sources for fine particles were: (i photochemical formation of carboxylic acids in vapor phase and a posterior gas-to-particle conversion onto sea salt particles; (ii emissions from anthropic sources with long range transportation processes; and (iii the interchanging of volatile species among atmospheric phases. In turn, for coarse particles, the predominant sources were: (i gas-phase species and ab/adsorbed onto pre-existing particles afterwards; (ii primary emission of coarse particles from anthropogenic sources; and (iii sea salt spray and/or soil resuspension. Finally, particle dry deposition was a very important mechanism representing air-to-sea fluxes of major species.

  3. Assessment of Innovation Effects of Mergers

    OpenAIRE

    Kern, Benjamin René

    2015-01-01

    Summary of Doctoral Dissertation Assessment of Innovation Effects of Mergers The adequate consideration of innovation effects of mergers in merger review was, and still is, one of the most controversially discussed issues between antitrust scholars. In this connection the question has been raised whether the traditional categories in competition law are sufficiently suitable for dealing with innovation aspects or whether new ...

  4. Models for mergers in higher education

    African Journals Online (AJOL)

    Rigor in qualitative research: the assessment of trustworthiness. The ... A possible model for higher education mergers, based on such ... The South African Universities' Vice-Chancellor's Association ..... the drafting of a merger plan and could prevent a joint culture and .... Creating a merger contract that includes. S.

  5. The Hubble sequence: a vestige of merger events

    CERN Document Server

    Hammer, F; Puech, M; Athanassoula, E; Rodrigues, M; Yang, Y; Delgado-Serrano, R

    2009-01-01

    Abr: We investigate whether the Hubble sequence can be reproduced by the relics of merger events. We verify that, at z~0.65, the abundant population of anomalous starbursts is mainly linked to the local spirals. We successfully reproduce their main morphological and kinematical properties by using gas modelling from Barnes' (2002) study of major mergers. All distant and massive starbursts can be distributed along a temporal sequence from the first passage to the nuclei fusion and then to the disk rebuilding phase. This later phase illustrated for J033245.11-274724.0, a compact galaxy dominated by a red, dust-enshrouded disk. It confirms the rebuilding spiral disk scenario -- a strong and recent reprocessing of most disks by major mergers -- because anomalous starbursts represent almost 50% of the galaxy population at z~0.65. Half of the present-day spirals were in major mergers phases 6 Gyrs ago, and almost all of them at z~1. It is time now to study in detail the formation of spiral disks and of their substr...

  6. Sussing Merger Trees: A proposed Merger Tree data format

    CERN Document Server

    Thomas, Peter A; Tweed, Dylan; Benson, Andrew J; Croton, Darren; Elahi, Pascal; Henriques, Bruno; Iliev, Ilian T; Knebe, Alexander; Lux, Hanni; Mao, Yao-Yuan; Neyrinck, Mark; Pearce, Frazer R; Rodriguez-Gomez, Vicente; Schneider, Aurel; Srisawat, Chaichalit

    2015-01-01

    We propose a common terminology for use in describing both temporal merger trees and spatial structure trees for dark-matter halos. We specify a unified data format in HDF5 and provide example I/O routines in C, FORTRAN and PYTHON.

  7. Galaxy And Mass Assembly (GAMA): Refining the Local Galaxy Merger Rate using Morphological Information

    CERN Document Server

    Casteels, Kevin R V; Bamford, Steven P; Salvador-Sole, Eduard; Norberg, Peder R; Agius, Nicola K; Baldry, Ivan; Brough, Sarah; Brown, Michael J I; Drinkwater, Michael J; Driver, Simon P; Graham, Alister W; Bland-Hawthorn, Joss; Hopkins, Andrew M; Kelvin, Lee S; Lopez-Sanchez, Angel R; Loveday, Jon; Robotham, Aaron S G; Vazquez-Mata, Jose A

    2014-01-01

    We use the Galaxy And Mass Assembly (GAMA) survey to measure the local Universe mass dependent merger fraction and merger rate using galaxy pairs and the CAS structural method, which identifies highly asymmetric merger candidate galaxies. Our goals are to determine which types of mergers produce highly asymmetrical galaxies, and to provide a new measurement of the local galaxy major merger rate. We examine galaxy pairs at stellar mass limits down to $M_{*} = 10^{8}M_{\\odot}$ with mass ratios of $$4:1) the lower mass companion becomes highly asymmetric, while the larger galaxy is much less affected. The fraction of highly asymmetric paired galaxies which have a major merger companion is highest for the most massive galaxies and drops progressively with decreasing mass. We calculate that the mass dependent major merger fraction is fairly constant at $\\sim1.3-2\\%$ between $10^{9.5}

  8. Inhibition of murine skin carcinogenesis by freeze-dried grape powder and other grape-derived major antioxidants.

    Science.gov (United States)

    Hanausek, Margaret; Spears, Erick; Walaszek, Zbigniew; Kowalczyk, Magdalena C; Kowalczyk, Piotr; Wendel, Courtney; Slaga, Thomas J

    2011-01-01

    Overexposure of the skin to carcinogenic insults causes a variety of adverse effects, among them the development of skin carcinomas. Since there is a need to develop efficient chemopreventive agents based on nutrition, our goal was to determine antioxidant and anti-carcinogenic properties of grapes by evaluating grape powder developed by the California Table Grape Commission. In order to elucidate the mechanism(s) of action of grape powder, three of the major antioxidant components found in grapes-resveratrol, catechin, quercetin, and grape seed extract, containing a proanthocyanidin B-2-gallate-were evaluated for their abilities to inhibit oxidative stress and to protect the immune system. Tested antioxidants given topically and/or systemically strongly inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-induced epidermal hyperplasia, proliferation, and inflammation. The hydroxylation of 2'-deoxyguanosine was markedly inhibited by topical and dietary administration of test variables, i.e., by approximately 40-70%. Simultaneous dietary and topical treatment with antioxidants reduced these biomarkers, showing strong additive and in some combinations synergistic effects. DMBA-mediated Ha-ras mutations in codon 61 were reduced by up to 50% with topical applications, but much higher inhibition was observed in mice treated with different combinations. The results of the present study clearly show impressive effects of combined topical and dietary treatments with above grape-derived antioxidants.

  9. Angular momenta, dynamical masses, and mergers of brightest cluster galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Jimmy; Tran, Kim-Vy [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Brough, Sarah [Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia); Gebhardt, Karl [Department of Astronomy, University of Texas at Austin, 1 University Station C1400, Austin, TX 78712 (United States); Von der Linden, Anja [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305-4085 (United States); Couch, Warrick J. [Centre for Astrophysics and Supercomputing, Swinburne University, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Sharp, Rob [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)

    2013-12-01

    Using the VIMOS integral field unit (IFU) spectrograph on the Very Large Telescope, we have spatially mapped the kinematic properties of 10 nearby brightest cluster galaxies (BCGs) and 4 BCG companion galaxies located within a redshift of z = 0.1. In the hierarchical formation model, these massive galaxies (10{sup 10.5} M {sub ☉} < M {sub dyn} < 10{sup 11.9} M {sub ☉}) are expected to undergo more mergers than lower mass galaxies, and simulations show that dry minor mergers can remove angular momentum. We test whether BCGs have low angular momenta by using the λ {sub Re} parameter developed by the SAURON and ATLAS{sup 3D} teams and combine our kinematics with Sloan Digital Sky Survey photometry to analyze the BCGs' merger status. We find that 30% (3/10) of the BCGs and 100% of the companion galaxies (4/4) are fast rotators as defined by the ATLAS{sup 3D} criteria. Our fastest rotating BCG has a λ {sub Re} = 0.35 ± 0.05. We increase the number of BCGs analyzed from 1 in the combined SAURON and ATLAS{sup 3D} surveys to 11 BCGs total and find that above M {sub dyn} ∼ 11.5 M {sub ☉}, virtually all galaxies, regardless of environment, are slow rotators. To search for signs of recent merging, we analyze the photometry of each system and use the G – M {sub 20} selection criteria to identify mergers. We find that 40% ± 20% of our BCGs are currently undergoing or have recently undergone a merger (within 0.2 Gyr). Surprisingly, we find no correlation between galaxies with high angular momentum and morphological signatures of merging.

  10. Essays on mergers and acquisitions

    NARCIS (Netherlands)

    Faelten, A.I.

    2016-01-01

    “Essays on Mergers and Acquisitions" tackles some of the most prominent business challenges related to M&A activity. The Introduction examines the reasons why deals fail through well-known case studies; Chapter 1 presents a new index measuring countries M&A maturity worldwide; Chapter 2 focus on the

  11. More Mergers,More Acquisitions

    Institute of Scientific and Technical Information of China (English)

    LAN XINZHEN

    2010-01-01

    @@ A new round of corporate mergers and acquisitions(M&As)is on the way.On September 6,the State Council announced that it would require companies in the automobile,iron and steel,cement,machinery manufacturing,electrolytic aluminum and rare earth industries to accelerate M&As.

  12. More Mergers,More Acquisitions

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China aims to maintain sound development of the national economy through M&As Anew round of corporate mergers and acquisitions (M&As) is on the way. On September 6, the State Council announced that it would require companies in the automobile, iron and steel, cement, machinery manufacturing, electro- lytic aluminum and rare earth industries to accelerate M&As.

  13. Do hospital mergers reduce costs?

    Science.gov (United States)

    Schmitt, Matt

    2017-03-01

    Proponents of hospital consolidation claim that mergers lead to significant cost savings, but there is little systematic evidence backing these claims. For a large sample of hospital mergers between 2000 and 2010, I estimate difference-in-differences models that compare cost trends at acquired hospitals to cost trends at hospitals whose ownership did not change. I find evidence of economically and statistically significant cost reductions at acquired hospitals. On average, acquired hospitals realize cost savings between 4 and 7 percent in the years following the acquisition. These results are robust to a variety of different control strategies, and do not appear to be easily explained by post-merger changes in service and/or patient mix. I then explore several extensions of the results to examine (a) whether the acquiring hospital/system realizes cost savings post-merger and (b) if cost savings depend on the size of the acquirer and/or the geographic overlap of the merging hospitals. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Magnetic fields during galaxy mergers

    CERN Document Server

    Rodenbeck, Kai

    2016-01-01

    Galaxy mergers are expected to play a central role for the evolution of galaxies, and may have a strong impact on their magnetic fields. We present the first grid-based 3D magneto-hydrodynamical simulations investigating the evolution of magnetic fields during merger events. For this purpose, we employ a simplified model considering the merger event of magnetized gaseous disks in the absence of stellar feedback and without a stellar or dark matter component. We show that our model naturally leads to the production of two peaks in the evolution of the average magnetic field strength within 5 kpc, within 25 kpc and on scales in between 5 and 25 kpc. The latter is consistent with the peak in the magnetic field strength reported by Drzazga et al. (2011) in a merger sequence of observed galaxies. We show that the peak on the galactic scale and in the outer regions is likely due to geometrical effects, as the core of one galaxy enters the outskirts of the other one. In addition, there is a physical enhancement of t...

  15. Dynamical evolution of primordial dark matter haloes through mergers

    Science.gov (United States)

    Ogiya, Go; Nagai, Daisuke; Ishiyama, Tomoaki

    2016-09-01

    Primordial dark matter (DM) haloes are the smallest gravitationally bound DM structures from which the first stars, black holes and galaxies form and grow in the early universe. However, their structures are sensitive to the free streaming scale of DM, which in turn depends on the nature of DM particles. In this work, we test the hypothesis that the slope of the central cusps in primordial DM haloes near the free streaming scale depends on the nature of merging process. By combining and analysing data from a cosmological simulation with the cutoff in the small-scale matter power spectrum as well as a suite of controlled, high-resolution simulations of binary mergers, we find that (1) the primordial DM haloes form preferentially through major mergers in radial orbits; (2) their central DM density profile is more susceptible to a merging process compared to that of galaxy- and cluster-sized DM haloes; (3) consecutive major mergers drive the central density slope to approach the universal form characterized by the Navarro-Frenk-White profile, which is shown to be robust to the impacts of mergers and serves an attractor solution for the density structure of DM haloes. Our work highlights the importance of dynamical processes on the structure formation during the Dark Ages.

  16. From Discs to Bulges: effect of mergers on the morphology of galaxies

    CERN Document Server

    Kannan, Rahul; Fontanot, Fabio; Moster, Benjamin P; Karman, Wouter; Somerville, Rachel S

    2015-01-01

    We study the effect of mergers on the morphology of galaxies by means of the simulated merger tree approach first proposed by Moster et al. This method combines N-body cosmological simulations and semi-analytic techniques to extract realistic initial conditions for galaxy mergers. These are then evolved using high resolution hydrodynamical simulations, which include dark matter, stars, cold gas in the disc and hot gas in the halo. We show that the satellite mass accretion is not as effective as previously thought, as there is substantial stellar stripping before the final merger. The fraction of stellar disc mass transferred to the bulge is quite low, even in the case of a major merger, mainly due to the dispersion of part of the stellar disc mass into the halo. We confirm the findings of Hopkins et al., that a gas rich disc is able to survive major mergers more efficiently. The enhanced star formation associated with the merger is not localised to the bulge of galaxy, but a substantial fraction takes place i...

  17. Chemical composition and major odor-active compounds of essential oil from PINELLIA TUBER (dried rhizome of Pinellia ternata) as crude drug.

    Science.gov (United States)

    Iwasa, Megumi; Iwasaki, Toshiki; Ono, Toshirou; Miyazawa, Mitsuo

    2014-01-01

    The chemical composition of the essential oil from PINELLIA TUBER (Japanese name: Hange), the dried rhizome of Pinellia ternata, was investigated by capillary gas chromatography (GC) and GC-mass spectrometry (MS) analyses. The oil obtained from Pinellia tuber was revealed the presence of 114 compounds, representing 90.6% of the total oil identified. This colorless oil had a spicy and woody odor. The main components of the oil were β-cubebene (8.8%), atractylon (7.8%), methyl eugenol (6.2%), and δ-cadinene (5.3%). Fifteen major odor-active compounds were identified in the essential oil from PINELLIA TUBER by the GC-olfactometry (GC-O) and aroma extract dilution analysis (AEDA). Among these, safrole (spicy) and β-vatirenene (woody) showed the highest flavor dilution (FD) factor (128), followed by paeonol (FD = 64; woody, spicy), α-humulene (FD = 64; woody), and β-phenylnaphthalene (FD = 64; spicy).

  18. Effect of nonfat dry milk and major whey components on interleukin-6 and interleukin-8 production in human intestinal epithelial-like Caco-2 cells.

    Science.gov (United States)

    Ustunol, Z; Wong, C

    2010-06-01

    Bovine nonfat dry milk (NDM) and major whey components (lactose, alpha-lactalbumin, and beta-lactoglobulin) were evaluated for their effects on IL-6 and IL-8 production in human intestinal-like Caco-2 cells unstimulated or stimulated with IL-1beta. All the whey components investigated and NDM induced IL-6 production by Caco-2 cells; the most significant increase was observed with beta-lactoglobulin. In the case of IL-1beta-stimulated cells, neither NDM nor the major whey components investigated contributed to the induction of IL-6 production after they were stimulated. Induction of IL-8 production by both alpha-lactalbumin and beta-lactoglobulin was higher than that by lactose and NDM; alpha-lactalbumin was a more potent inducer of IL-8 than beta-lactoglobulin and IL-1beta alone in both unstimulated and stimulated cells. In Caco-2 cells that were stimulated with IL1-beta, NDM and all the major whey components investigated had a synergistic effect on induction of IL-8 production, indicating that IL-8 induction was amplified by prior stimulation of cells by IL-1beta. This synergistic effect was not observed with IL-6. Our results suggest that immunomodulatory properties of milk components may be affected by other complex events in the gut.

  19. The dominant role of mergers in the size evolution of massive early-type galaxies since z similar to 1

    NARCIS (Netherlands)

    López-Sanjuan, C.; Le Fèvre, O.; Ilbert, O.; Tasca, L. A. M.; Bridge, C.; Cucciati, O.; Kampczyk, P.; Pozzetti, L.; Xu, C.K.; Carollo, C. M.; Contini, T.; Kneib, J. -P; Lilly, S. J.; Mainieri, V.; Renzini, A.; Sanders, D.; Scodeggio, M.; Scoville, N. Z.; Taniguchi, Y.; Zamorani, G.; Aussel, H.; Bardelli, S.; Bolzonella, M.; Bongiorno, A.; Capak, P.; Caputi, K.; de la Torre, S.; de Ravel, L.; Franzetti, P.; Garilli, B.; Iovino, A.; Knobel, C.; Kovač, K.; Lamareille, F.; Le Borgne, J. -F; Le Brun, V.; Le Floc'h, E.; Maier, C.; McCracken, H. J.; Mignoli, M.; Pelló, R.; Peng, Y.; Pérez-Montero, E.; Presotto, V.; Ricciardelli, E.; Salvato, M.; Silverman, J. D.; Tanaka, M.; Tresse, L.; Vergani, D.; Zucca, E.; Barnes, L.; Bordoloi, R.; Cappi, A.; Cimatti, A.; Coppa, G.; Koekemoer, A.; Liu, C.T.; Moresco, M.; Nair, P.; Oesch, P.; Schawinski, K.; Welikala, N.

    2012-01-01

    Aims. The role of galaxy mergers in massive galaxy evolution, and in particular to mass assembly and size growth, remains an open question. In this paper we measure the merger fraction and rate, both minor and major, of massive early-type galaxies (M-star >= 10(11) M-circle dot) in the COSMOS field,

  20. Mergers and Mass Accretion Rates in Galaxy Assembly: The Millennium Simulation Compared to Observations of z~2 Galaxies

    CERN Document Server

    Genel, S; Bouché, N; Sternberg, A; Naab, T; Förster-Schreiber, N M; Shapiro, K L; Tacconi, L J; Lutz, D; Cresci, G; Buschkamp, P; Davies, R I; Hicks, E K S

    2008-01-01

    Recent observations of UV-/optically selected, massive star forming galaxies at z~2 indicate that the baryonic mass assembly and star formation history is dominated by continuous rapid accretion of gas and internal secular evolution, rather than by major mergers. We use the Millennium Simulation to build new halo merger trees, and extract halo merger fractions and mass accretion rates. We find that even for halos not undergoing major mergers the mass accretion rates are plausibly sufficient to account for the high star formation rates observed in z~2 disks. On the other hand, the fraction of major mergers in the Millennium Simulation is sufficient to account for the number counts of submillimeter galaxies (SMGs), in support of observational evidence that these are major mergers. When following the fate of these two populations in the Millennium Simulation to z=0, we find that subsequent mergers are not frequent enough to convert all z~2 turbulent disks into elliptical galaxies at z=0. Similarly, mergers canno...

  1. Massive black hole binary evolution in gas-rich mergers

    CERN Document Server

    Colpi, M; Dotti, M; Mayer, L

    2009-01-01

    We report on key studies on the dynamics of black holes (BHs) in gas-rich galaxy mergers that underscore the vital role played by gas dissipation in promoting BH inspiral down to the smallest scales ever probed with use of high-resolution numerical simulations. In major mergers, the BHs sink rapidly under the action of gas-dynamical friction while orbiting inside the massive nuclear disc resulting from the merger. The BHs then bind and form a Keplerian binary on a scale of 5 pc. In minor mergers, BH pairing proceeds down to the minimum scale explored of 10-100 pc only when the gas fraction in the less massive galaxy is comparatively large to avoid its tidal and/or ram pressure disruption and the wandering of the light BH in the periphery of the main halo. Binary BHs enter the gravitational wave dominated inspiral only when their relative distance is typically of 0.001 pc. If the gas preserves the degree of dissipation expected in a star-burst environment, binary decay continues down to 0.1 pc, the smallest le...

  2. Merger Histories of Galaxy Halos and Implications for Disk Survival

    CERN Document Server

    Stewart, Kyle R; Wechsler, Risa H; Maller, Ariyeh H; Zentner, Andrew R

    2007-01-01

    We study the merger histories of galaxy dark matter halos using a high resolution LCDM N-body simulation. Our merger trees follow ~17,000 halos with masses M_0 = (10^11--10^13) Msun at z=0 and track accretion events involving objects as small as m = 10^10 Msun. We find that mass assembly is remarkably self-similar in m/M_0, and dominated by mergers that are ~10% of the final halo mass. While very large mergers, m > 0.4 M_0, are quite rare, sizeable accretion events, m ~ 0.1 M_0, are common. Over the last 10 Gyr, an overwhelming majority (~95%) of Milky Way-sized halos with M_0 = 10^12 Msun have accreted at least one object with greater total mass than the Milky Way disk (m > 5x10^10 Msun), and approximately 70% have accreted an object with more than twice that mass (m > 10^11 Msun). Our results raise serious concerns about the survival of thin-disk dominated galaxies within the current paradigm for galaxy formation in a CDM universe. In order to achieve a ~70% disk-dominated fraction in Milky Way-sized CDM ha...

  3. A meeting of minds. Offshore drilling contractor mergers

    Energy Technology Data Exchange (ETDEWEB)

    Flatern, R. von

    2002-03-01

    Over about the past ten years, the offshore drilling industry had become over populated but as result of mergers/takeovers the number of major players is now only about half a dozen. One of the products of the consolidation is GlobalSantaFe, the head of which is C Sted Garber - he discusses the present set-up. Changes have also been made in the service sector where expansion has lead to bigger companies offering a fully comprehensive range from seismic work to plug and abandonment. The article gives details of how Global and Santa Fe were naturals for a merger and reports on the track records of Garber and the chairman of the new board Bob Rose. The concerns, particularly those of the employees and the customers, when a merger takes place are discussed. Garber is optimistic about the future of the petroleum and gas business and briefly discusses the economic outlook. In terms of fleet size, GlobalSantaFe is now third but the whole business of mergers/takeovers is still evolving.

  4. Compact Binary Mergers as Multimessenger Sources of Gravitational Waves

    Science.gov (United States)

    Shapiro, Stuart

    2015-04-01

    On the centennial anniversary of Einstein's theory of general relativity, we are on the verge of directly detecting one of its most remarkable predictions - gravitational waves (GWs). The inspiral and merger of compact binaries - binaries with black hole, neutron star or white dwarf companions - are among the most promising sources of GWs. Many of these sources are likely to generate observable electromagnetic (EM) and/or neutrino counterparts to the GWs, constituting a major advance in multimessenger astronomy. By way of illustration, we describe recent magnetohydrodynamic simulations in general relativity (GRMHD) that show how black hole-neutron star mergers can launch jets, lending support to the idea that such mergers could be the engines that power short-hard gamma-ray bursts. We also discuss other recent GRMHD simulations that show how an inspiraling, supermassive binary black hole in a galaxy core stirs and accretes magnetized plasma that orbits the holes in a circumbinary disk. This process can generate ``precursor'' and ``aftermath'' EM radiation with respect to the peak GW emission at merger. Computer-generated movies highlighting some of these simulations will be shown. We gratefully acknowledge support from NSF Grant PHY-1300903 and NASA Grant NNX13AH44G at the University of Illinois at Urbana-Champaign.

  5. Resolving The Generation of Starburst Winds in Galaxy Mergers

    CERN Document Server

    Hopkins, Philip F; Murray, Norman; Hernquist, Lars; Narayanan, Desika; Hayward, Christopher C

    2013-01-01

    We study galaxy super-winds driven in major mergers, using pc-resolution simulations with detailed models for stellar feedback that can self-consistently follow the formation/destruction of GMCs and generation of winds. The models include molecular cooling, star formation at high densities in GMCs, and gas recycling and feedback from SNe (I&II), stellar winds, and radiation pressure. We study mergers of systems from SMC-like dwarfs and Milky Way analogues to z~2 starburst disks. Multi-phase super-winds are generated in all passages, with outflow rates up to ~1000 M_sun/yr. However, the wind mass-loading efficiency (outflow rate divided by SFR) is similar to that in isolated galaxy counterparts of each merger: it depends more on global galaxy properties (mass, size, escape velocity) than on the dynamical state of the merger. Winds tend to be bi- or uni-polar, but multiple 'events' build up complex morphologies with overlapping, differently-oriented bubbles/shells at a range of radii. The winds have complex...

  6. Multiple minor mergers: formation of elliptical galaxies and constraints for the growth of spiral disks

    CERN Document Server

    Bournaud, Frederic; Combes, Francoise

    2007-01-01

    Multiple, sequential mergers are unavoidable in the hierarchical build-up picture of galaxies, in particular for the minor mergers that are frequent and highly likely to have occured several times for most present-day galaxies. However the effect of repeated minor mergers on galactic structure and evolution has not been studied systematically so far. In this paper, we present a numerical study of multiple, subsequent, minor galaxy mergers, with various mass ratios ranging from 4:1 to 50:1. The N-body simulations include gas dynamics and star formation. We study the morphological and kinematical properties of the remnants, and show that several so-called "minor" mergers can lead to the formation of elliptical-like galaxies, that have global morphological and kinematical properties similar to that observed in real elliptical galaxies. The properties of these systems are compared with that of elliptical galaxies produced by the standard scenario of one single major merger. We thus show that repeated minor merger...

  7. Global properties of multiple merger remnants

    CERN Document Server

    Weil, M L; Weil, Melinda L; Hernquist, Lars

    1995-01-01

    Merger remnants of small groups of galaxies are contrasted with relics of mergers of pairs of galaxies to determine which process produces objects that best compare to real ellipticals. In both cases, the progenitors consist of self-gravitating disks, halos, and, sometimes, bulges. Pairs of galaxies merge from orbits that initially have zero--energy. The systems that produce multiple merger remnants are dense, six--member groups in virial equilibrium with low velocity dispersions. Multiple and pair mergers produce remnants which differ in both their spatial and kinematic properties. Multiple merger remnants have small triaxialities and are most likely to appear nearly round from most viewing angles. They possess cores, with sizes of a few tenths of an effective radius, that are more extended than pair remnant cores, even when bulges are included in the progenitors. In multiple mergers, the spin of all components -- halo, disk, and bulge -- increases and, while velocity dispersion dominates in the central regi...

  8. Gas-Rich Mergers in LCDM: Disk Survivability and the Baryonic Assembly of Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Kyle R.; Bullock, James S.; /UC, Irvine; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Maller, Ariyeh H.; /New York City Coll. Tech.

    2009-08-03

    We use N-body simulations and observationally-normalized relations between dark matter halo mass, stellar mass, and cold gas mass to derive robust expectations about the baryonic content of major mergers out to redshift z {approx} 2. First, we find that the majority of major mergers (m/M > 0.3) experienced by Milky Way size dark matter halos should have been gas-rich, and that gas-rich mergers are increasingly common at high redshift. Though the frequency of major mergers into galaxy halos in our simulations greatly exceeds the observed late-type galaxy fraction, the frequency of gas-poor major mergers is consistent with the observed fraction of bulge-dominated galaxies across the halo mass range M{sub DM} {approx} 10{sup 11} - 10{sup 13} M{sub {circle_dot}}. These results lend support to the conjecture that mergers with high baryonic gas fractions play an important role in building and/or preserving disk galaxies in the universe. Secondly, we find that there is a transition mass below which a galaxy's past major mergers were primarily gas-rich and above which they were gas poor. The associated stellar mass scale corresponds closely to that marking the observed bimodal division between blue, star-forming, disk-dominated systems and red, bulge-dominated systems with old populations. Finally, we find that the overall fraction of a galaxy's cold baryons deposited directly via major mergers is substantial. Approximately 30% of the cold baryonic material in M{sub star} {approx} 10{sup 10} M{sub {circle_dot}} (M{sub DM} {approx} 10{sup 11.5} M{sub {circle_dot}}) galaxies is accreted as cold gas in major mergers. For more massive galaxies with M{sub star} {approx} 10{sup 11} M{sub {circle_dot}} (M{sub DM} {approx} 10{sup 13} M{sub {circle_dot}} the fraction of baryons amassed in mergers is even higher, {approx} 50%, but most of these accreted baryons are delivered directly in the form of stars. This baryonic mass deposition is almost unavoidable, and provides a

  9. LEGAL CONSEQUENCES OF MERGERS AND ACQUISITIONS

    Directory of Open Access Journals (Sweden)

    Amelia-Raluca ONIŞOR

    2016-05-01

    Full Text Available The research analyses the legal effects of mergers and acquisitions from the Romanian Company Law perspective, underlining certain general principles, the procedure of annulment of such a legal transformation of companies and the protection of the employees of companies participating in the merger according to the Law no. 67/2006. These consequences of mergers and acquisions are to be seen in the broader light of the most important purpose of this legal instrument, maximizing financial and organizational efficiencies, thus legal certainty is a desirable goal to be assumed by any merger regulation.

  10. Understanding Information Systems Integration Deficiencies in Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Kettinger, William J.

    2017-01-01

    Information systems (IS) integration is a critical challenge for value-creating mergers and acquisitions. Appropriate design and implementation of IS integration is typically a precondition for enabling a majority of the anticipated business benefits of a combined organization. Often, IS integrat......Information systems (IS) integration is a critical challenge for value-creating mergers and acquisitions. Appropriate design and implementation of IS integration is typically a precondition for enabling a majority of the anticipated business benefits of a combined organization. Often......, IS integration projects are subject to deficiencies (e.g., loss of the target firm’s business capabilities with expedited integration) that limit value creation. Drawing on a configurational perspective, we reanalyze 37 published case studies of problematic IS integrations and identify the potential deficiencies...... are reported, we discuss approaches for managing IS integration to avoid realizing the actualization of deficiencies....

  11. School of Education Mergers: Institutional Survival or Administrative Madness?

    Science.gov (United States)

    Barr, Robert D.

    1985-01-01

    This article describes the merger of teacher education programs at neighboring institutions and the problems and benefits accruing from the merger. The efficacy of the merger concept is examined. (MT)

  12. Dry Eye

    Science.gov (United States)

    ... Eye > Facts About Dry Eye Facts About Dry Eye This information was developed by the National Eye ... the best person to answer specific questions. Dry Eye Defined What is dry eye? Dry eye occurs ...

  13. Double White Dwarf Merger Rates

    Science.gov (United States)

    Toonen, Silvia; Nelemans, Gijs; Portegies Zwart, Simon

    2013-01-01

    Type Ia supernovae (SNe Ia) are very successfully used as standard candles on cosmological distance scales, but so far the nature of the progenitor(s) is unclear. A possible scenario for SNe Ia are merging carbon/oxygen white dwarfs with a combined mass exceeding the Chandrasekhar mass. We determine the theoretical rates and delay time distribution of these mergers for two different common envelope prescriptions and metallicities. The shape of the delay time distributions is rather insensitive to the assumptions. The normalization is a factor ~3-13 too low compared to observations.

  14. 12 CFR 619.9210 - Merger.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Merger. 619.9210 Section 619.9210 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9210 Merger. Combining of one or more organizational entities into another similar entity....

  15. Tax Management in Cross-Border Mergers

    OpenAIRE

    Marcin Jamrozy

    2011-01-01

    Tax management is one of the essential aspects of mergers. Mergers of companies that are residents of different Member States are not hampered by disadvantages arising from tax provisions; this applies to income-, capital-, as well as to value added taxation.

  16. Managing in a merger and acquisition era.

    Science.gov (United States)

    Holdren, R C

    1990-01-01

    Medical group administrators are quickly learning what big business has known for years-mergers and acquisitions represent a new and powerful option. If this option is to be employed successfully, however, group management has to understand the terms and be prepared well before merger or acquisition talk begins.

  17. Mergers, Strategic Investments and Antitrust Policy

    NARCIS (Netherlands)

    D. Deneffe (Daniel); P.P. Wakker (Peter)

    1996-01-01

    textabstractEstablished firms can diversify into new markets in two distinct modes: through internal development or through conglomerate merger. Building on a dynamic three-stage bargaining model with variable threats, this paper shows that a lenient antitrust position toward horizontal mergers can

  18. Mergers, strategic investments and antitrust policy

    NARCIS (Netherlands)

    P.P. Wakker; D. Deneffe

    1996-01-01

    Established firms can diversify into new markets in two distinct modes: through internal development or through conglomerate merger. Building on a dynamic three-stage bargaining model with variable threats, this paper shows that a lenient antitrust position toward horizontal mergers can induce estab

  19. Mergers, strategic investments and antitrust policy

    NARCIS (Netherlands)

    Wakker, P.P.; Deneffe, D.

    1996-01-01

    Established firms can diversify into new markets in two distinct modes: through internal development or through conglomerate merger. Building on a dynamic three-stage bargaining model with variable threats, this paper shows that a lenient antitrust position toward horizontal mergers can induce

  20. Mergers, Strategic Investments and Antitrust Policy

    NARCIS (Netherlands)

    D. Deneffe (Daniel); P.P. Wakker (Peter)

    1996-01-01

    textabstractEstablished firms can diversify into new markets in two distinct modes: through internal development or through conglomerate merger. Building on a dynamic three-stage bargaining model with variable threats, this paper shows that a lenient antitrust position toward horizontal mergers can

  1. Welfare Effect of Mergers and Trade Liberalization

    NARCIS (Netherlands)

    Ray Chaudhuri, A.; Benchekroun, H.

    2008-01-01

    In a two-country model where firms behave à la Cournot, we show that marginal and non-marginal trade liberalization have different effects on the social desirability of horizontal mergers. Marginal tariff reductions increase (decrease) the desirability of merger at sufficiently low (high) tariff lev

  2. Distribution of Luminosity, Gas, and Stellar Populations in Local Luminous Infrared Galaxies as a Function of Merger Stage

    Science.gov (United States)

    Larson, Kirsten L.

    Luminous infrared galaxies (LIRGs) are galaxies where intense infrared emission is driven by star formation and active galactic nuclei. In the local universe it is clear that many LIRGs are major mergers of gas rich spiral galaxies. I have performed a careful visual classification of local (z 1011:5Lsun are merging galaxies, while below this luminosity threshold, minor mergers and secular processes dominate. The mean molecular gas fraction ( MGF = MH2=(M* + MH2)) has an average value of 18+/-2% for non-interacting and early stage major merger LIRGs, which increases to 33±3% for intermediate stage major merger LIRGs. This is consistent with the hypotheses that during the early-mid stages of major mergers, atomic gas (H I) at large galactocentric radii is swept inward where it is converted into molecular gas (H2). The interactions also drive star formation throughout the galaxy as is evident by the blue B -- I color for LIRGs at every merger stage. Late stage mergers show a reddening in their nuclear 2 kpc region, presumably also from increase in nuclear gas and dust as the galaxy nuclei coalesce. Using deep Spitzer 3.6 and 4.5 mum imaging, I find that these interactions form tidal tails and debris that extend out to 80 kpc from the galaxy nuclei. This large scale tidal debris builds up over the course of a major merger and forms up-bending infrared surface brightness profiles. I further investigate the utility of automated morphology parameters and present a refined surface brightness method for gini, M20, and concentration indices. With this new method the M20 parameter correlates with merger stage and, in combination with gini and concentration, provides a more reliable automated separation between interacting and non-interacting galaxies than previous schemes.

  3. Mergers and integrated care: the Quebec experience

    Directory of Open Access Journals (Sweden)

    Louis Demers

    2013-02-01

    Full Text Available As a researcher, I have studied the efforts to increase the integration of health and social services in Quebec, as well as the mergers in the Quebec healthcare system. These mergers have often been presented as a necessary transition to break down the silos that compartmentalize the services dispensed by various organisations. A review of the studies about mergers and integrated care projects in the Quebec healthcare system, since its inception, show that mergers cannot facilitate integrated care unless they are desired and represent for all of the actors involved an appropriate way to deal with service organisation problems. Otherwise, mergers impede integrated care by creating increased bureaucratisation and standardisation and by triggering conflicts and mistrust among the staff of the merged organisations. It is then preferable to let local actors select the most appropriate organisational integration model for their specific context and offer them resources and incentives to cooperate.

  4. Risks of Mergers and Acquisitions Processes

    Directory of Open Access Journals (Sweden)

    Skitsko Volodymyr I.

    2017-06-01

    Full Text Available Despite structural changes both in the economies of individual countries and in the world at large, the size of the merger/acquisition market is not declining and is tending to grow further. However, uncertainty in the global environment increases the importance of proper analysis, assessment and risk management in merger/acquisition transactions. Using the relevant research and publications by various authors, we have built a general ranking of the significance of merger and acquisition risks according to phases of the indicated process, with comparison of individual risk ratings, based on the publications by authors from Central and Eastern Europe and other countries around the world. The ranking of risks and threats of mergers/acquisitions proposed in this work can be considered one of the most complete for today. Further research needs to focus on the analysis, evaluation, and modeling of merger/acquisition risks, which occupy the top of the ranking, presented by the article.

  5. The formation of globular clusters through minihalo-minihalo mergers

    CERN Document Server

    Trenti, Michele; Jimenez, Raul

    2015-01-01

    We propose a novel scenario for the formation of Globular Clusters (GCs) based on the merger of two or more atomic cooling halos at high-redshift (z>6). The model naturally fulfills several key observational constraints on GCs that have emerged in the last decade. Specifically, absolute and relative ages, widespread presence of multiple stellar populations, spatial distribution around host galaxies, and correlations between galactocentric radius and metallicity. In our framework, the oldest globular clusters form the first generation stars as an intense burst in the center of a minihalo that grows above the threshold for hydrogen cooling (halo mass M_h~1e8 Msun) and undergoes a major merger within the cooling timescale (~150 Myr). Subsequent minor mergers and sustained gas infall bring new supply of pristine gas at the halo center, diluting AGB ejecta, and triggering additional bursts of star formation which form multiple generation of stars in the majority of the clusters. The DM halo around the GC is then s...

  6. Dynamical analysis of galaxy cluster merger Abell 2146

    CERN Document Server

    White, J A; King, L J; Lee, B E; Russell, H R; Baum, S A; Clowe, D I; Coleman, J E; Donahue, M; Edge, A C; Fabian, A C; Johnstone, R M; McNamara, B R; ODea, C P; Sanders, J S

    2015-01-01

    We present a dynamical analysis of the merging galaxy cluster system Abell 2146 using spectroscopy obtained with the Gemini Multi-Object Spectrograph on the Gemini North telescope. As revealed by the Chandra X-ray Observatory, the system is undergoing a major merger and has a gas structure indicative of a recent first core passage. The system presents two large shock fronts, making it unique amongst these rare systems. The hot gas structure indicates that the merger axis must be close to the plane of the sky and that the two merging clusters are relatively close in mass, from the observation of two shock fronts. Using 63 spectroscopically determined cluster members, we apply various statistical tests to establish the presence of two distinct massive structures. With the caveat that the system has recently undergone a major merger, the virial mass estimate is M_vir = 8.5 +4.3 -4.7 x 10 ^14 M_sol for the whole system, consistent with the mass determination in a previous study using the Sunyaev-Zeldovich signal....

  7. The role of mergers and halo spin in shaping galaxy morphology

    CERN Document Server

    Rodriguez-Gomez, Vicente; Genel, Shy; Pillepich, Annalisa; Zjupa, Jolanta; Nelson, Dylan; Griffen, Brendan; Torrey, Paul; Snyder, Gregory F; Vogelsberger, Mark; Springel, Volker; Ma, Chung-Pei; Hernquist, Lars

    2016-01-01

    Mergers and the spin of the dark matter halo are factors traditionally believed to determine the morphology of galaxies within a $\\Lambda$CDM cosmology. We study this hypothesis by considering approximately 18,000 central galaxies at $z=0$ with stellar masses $M_{\\ast} > 10^{9} \\, {\\rm M}_{\\odot}$ selected from the Illustris cosmological hydrodynamic simulation. The fraction of accreted stars -- which measures the importance of massive, recent and dry mergers relative to in situ star formation -- increases steeply with galaxy stellar mass, from less than 5 per cent in dwarfs to 80 per cent in the most massive objects, and the impact of mergers on galaxy morphology increases accordingly. For galaxies with $M_{\\ast} > 10^{11} \\, {\\rm M}_{\\odot}$, mergers have the expected effect: if gas-poor they promote the formation of spheroidal galaxies, whereas gas-rich mergers favour the formation and survivability of massive discs. This trend, however, breaks at lower masses. For objects with $M_{\\ast} < 10^{11} \\, {\\...

  8. Quantifying Substructure Measures In X-ray Images of Galaxy Cluster Mergers With SLAM

    Science.gov (United States)

    Chatzikos, Marios; Sarazin, C. L.; O'Shea, B. W.

    2014-01-01

    I use the Simulation Library of Astrophysical galaxy cluster Mergers (SLAM) database to quantify the effects of mergers on X-ray observables. SLAM consists of a set of 156 adiabatic simulations of binary galaxy cluster mergers, that covers 2 orders of magnitude in the mass of the primary cluster, four values for the mass contrast, and four values for the angular momentum of the collision. In this talk I describe results on substructure measures obtained for various viewing angles. I have quantified the substructure in X-ray images using both center shifts and power ratios. Mergers of intermediate mass contrasts produce substructure signals that can persist in X-ray images for at least 1-2 sound crossing times. The amplitude of both measures depends strongly on the initial mass contrast. The measures for major mergers (mass contrast less than 3) appear to depend on the system mass, while for minor mergers (mass contrast between 3 and 10) they are generally independent of the system mass. Neither measure reflects the true dynamical state of the system closely, although the center shifts appear to be a better proxy. Comparisons with the virial and hydrostatic disequilibrium parameters reveal that there is no value of either substructure measure that unambiguously distinguishes merging from relaxing systems. Implications for SZE observations will also be discussed.

  9. Merger Histories of Galaxy Halos and Implications for Disk Survival

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Kyle R.; Bullock, James S.; Wechsler, Risa H.; Maller, Ariyeh H.; Zentner, Andrew R.

    2008-05-16

    The authors study the merger histories of galaxy dark matter halos using a high resolution {Lambda}CDM N-body simulation. The merger trees follow {approx} 17,000 halos with masses M{sub 0} = (10{sup 11} - 10{sup 13})h{sup -1}M{sub {circle_dot}} at z = 0 and track accretion events involving objects as small as m {approx_equal} 10{sup 10} h{sup -1}M{sub {circle_dot}}. They find that mass assembly is remarkably self-similar in m/M{sub 0}, and dominated by mergers that are {approx}10% of the final halo mass. While very large mergers, m {approx}> 0.4 M{sub 0}, are quite rare, sizeable accretion events, m {approx} 0.1 M{sub 0}, are common. Over the last {approx} 10 Gyr, an overwhelming majority ({approx} 95%) of Milky Way-sized halos with M{sub 0} = 10{sup 12} h{sup -1}M{sub {circle_dot}} have accreted at least one object with greater total mass than the Milky Way disk (m > 5 x 10{sup 10} h{sup -1}M{sub {circle_dot}}), and approximately 70% have accreted an object with more than twice that mass (m > 10{sup 11} h{sup -1}M{sub {circle_dot}}). The results raise serious concerns about the survival of thin-disk dominated galaxies within the current paradigm for galaxy formation in a {Lambda}CDM universe. in order to achieve a {approx} 70% disk-dominated fraction in Milky Way-sized {Lambda}CDM halos, mergers involving m {approx_equal} 2 x 10{sup 11} h{sup -1}M{sub {circle_dot}} objects must not destroy disks. Considering that most thick disks and bulges contain old stellar populations, the situation is even more restrictive: these mergers must not heat disks or drive gas into their centers to create young bulges.

  10. An assessment of bank merger success in Germany

    NARCIS (Netherlands)

    Koetter, Michael

    2008-01-01

    German banks have experienced a merger wave since the early 1990s. However, the success or bank mergers remains a continuous matter or debate. This paper suggests a taxonomy to evaluate post-merger performance on the basis of cost and profit efficiency (CE and PE). I identify successful mergers as t

  11. Analysis of International Mergers and Acquisitions in the Pharmaceutical Industry

    Directory of Open Access Journals (Sweden)

    Božo Matić

    2011-07-01

    Full Text Available There are numerous researches which analyze mergers and acquisitions, but most of them do not focus on a certain industry, but their sample considers companies from different industries. This paper focuses on mergers and acquisitions in the pharmaceutical industry. It is assumed that pharmaceutical companies with no experience in mergers and acquisitions achieve better results in relatively small and domestic mergers and acquisitions while pharmaceutical companies with greater experience in mergers and acquisitions are successful even in bigger and international mergers and acquisitions. Bigger mergers and acquisitions and international mergers and acquisitions are more risky for the companies so lack of experience in mergers and acquisitions additionally increases risks during the process of mergers and acquisitions. On average, such increase of the risk results in lower returns for stock owners of pharmaceutical companies.

  12. The genetics of a pharma merger.

    Science.gov (United States)

    Sanseau, Philippe; Chabot-Fletcher, Marie; Browne, Michael J

    2009-04-01

    The 1990s and early years of this century have seen a series of large-scale mergers and acquisitions in the Pharmaceutical and Biotech arena. These activities each required integration at multiple levels. One of the most important activities is the integration of the R&D pipelines of the participants. We outline the combined portfolio and bioinformatic strategy that was used, and detail the lessons learned for the longer term, from the GlaxoWellcome-SmithKline-Beecham merger in 2000. To date, this has been the largest merger of two equally sized Pharma R&D organisations.

  13. A Behavioral Theory of the Merger: Dynamics of the Post-Merger Integration Process

    Science.gov (United States)

    2014-05-01

    these mathematical models can provide direction, if not an entire framework , for empirical study of the post- merger integration process at a later...of the Hofstede (1983) values. Cultural complexity is of immediate relevance in the post-merger integration process. In order to unify two...entirely new culture, for NewCo itself. The relative difference ( Hofstede , 1983) between the two pre- merger cultures, in particular the difference in the

  14. Can this merger be saved?

    Science.gov (United States)

    Cliffe, S

    1999-01-01

    In this fictional case study, a merger that looked like a marriage made in heaven to those at corporate headquarters is feeling like an infernal union to those on the ground. The merger is between Synergon Capital, a U.S. financial-services behemoth, and Beauchamp, Becker & Company, a venerable British financial-services company with strong profits and an extraordinarily loyal client base of wealthy individuals. Beauchamp also boasts a strong group of senior managers led by Julian Mansfield, a highly cultured and beloved patriarch who personifies all that's good about the company. Synergon isn't accustomed to acquiring such companies. It usually encircles a poorly managed turnaround candidate and then, once the deal is done, drops a neutron bomb on it, leaving file cabinets and contracts but no people. Before acquiring Beauchamp, Synergon's macho men offered loud assurances that they would leave the tradition-bound company alone-provided, of course, that Beauchamp met the ambitious target numbers and showed sufficient enthusiasm for cross-selling Synergon's products to its wealthy clients. In charge of making the acquisition work is Nick Cunningham, one of Synergon's more thoughtful executives. Nick, who was against the deal from the start, is the face and voice of Synergon for Julian Mansfield. And Mansfield, in his restrained way, is angry at the constant flow of bureaucratic forms, at the rude demands for instant information, at the peremptory changes. He's even dropping broad hints at retirement. Nick has already been warned: if Mansfield goes, you go. Six commentators advise Nick on how to save his job by bringing peace and prosperity to the feuding couple.

  15. The Impact of Merger Status and Relative Representation on Identification with a Merger Group

    Directory of Open Access Journals (Sweden)

    Filip Boen

    2005-12-01

    Full Text Available This experiment tested to what extent identification with a new merger group is determined by the status of that merger group and by the relative representation of the pre-merger ingroup. One hundred university students were assigned to a team of 'inductive' thinkers, and were later merged with a team of 'deductive' thinkers to form a team of 'analyst' thinkers. The status of the merger group (low, high and the relative representation of the ingroup into the novel merger group (low, high were manipulated. Participants identified more with the merger group in the high than in the low status condition, and they identified more in the high than in the low representation condition. The predicted interaction between relative representation and merger status was not significant. However, relative representation did interact with participants' pre-merger identification: Pre- and post-merger identification were positively related when the ingroup was highly represented, but 'negatively' when the ingroup was lowly represented.

  16. Relics as Probes of Galaxy Cluster Mergers

    Indian Academy of Sciences (India)

    R. J. van Weeren; M. Brüggen; H. J. A. Röttgering; M. Hoeft

    2011-12-01

    Galaxy clusters grow by mergers with other clusters and galaxy groups. These mergers create shocks within the intracluster medium (ICM). It is proposed that particles can be accelerated to extreme energies within the shocks. In the presence of a magnetic field these particles should then form large regions emitting synchrotron radiation, creating the so-called radio relics. An example of a cluster with relics is CIZA J2242.8+5301. Here we present hydrodynamical simulations of idealized binary cluster collisions with the aim of constraining the merger scenario for this cluster. We conclude that by using the location, size and width of double radio relics we can set constraints on the mass ratios, impact parameters, time scales, and viewing geometries of binary cluster merger events.

  17. DATA MINING THE GALAXY ZOO MERGERS

    Data.gov (United States)

    National Aeronautics and Space Administration — DATA MINING THE GALAXY ZOO MERGERS STEVEN BAEHR, ARUN VEDACHALAM, KIRK BORNE, AND DANIEL SPONSELLER Abstract. Collisions between pairs of galaxies usually end in the...

  18. Mergers and innovation in the pharmaceutical industry.

    Science.gov (United States)

    Comanor, William S; Scherer, F M

    2013-01-01

    Conflicting trends confound the pharmaceutical industry. The productivity of pharmaceutical innovation has declined in recent years. At the same time, the cohort of large companies who are the leading engines of pharmaceutical R&D has become increasingly concentrated. The concurrent presence of these trends is not sufficient to determine causation. In response to lagging innovation prospects, some companies have sought refuge in mergers and acquisitions to disguise their dwindling prospects or gain R&D synergies. On the other hand, the increased concentration brought on by recent mergers may have contributed to the declining rate of innovation. In this paper, we consider the second of these causal relationships: the likely impact of the recent merger wave among the largest pharmaceutical companies on the rate of innovation. In other words, have recent mergers, which may have been taken in response to lagging innovation, represented a self-defeating strategy that only made industry outcomes worse?

  19. Mergers and acquisitions: a most strategic decision.

    Science.gov (United States)

    Laine, Mike; Tyler, David

    2007-11-01

    Five steps are basic to successfully concluding (or deciding not to conclude) a merger or acquisition: Identify targets. Begin with the end in mind. Choose a transaction team. Perform due diligence. Commit to the deal--or to no deal.

  20. Multiemployer Pension Plan Terminations, Mergers, and Insolvencies

    Data.gov (United States)

    Pension Benefit Guaranty Corporation — A listing of multiemployer pension plan terminations, mergers, and insolvencies reported to the PBGC for the current fiscal year. This data set will be updated...

  1. R&D investments fostering horizontal mergers

    OpenAIRE

    Cabolis, C.; Manasakis, C.; MORENO, Diego; Petrakis, Emmanuel

    2016-01-01

    We study a homogenous good triopoly in which firms first choose their cost-reducing R&D investments and consider alternative merger proposals, and then compete à la Cournot in the ensuing industry. We identify conditions under which both horizontal mergers and non integration are sustained by Coalition-Proof Nash equilibria (CPNE). These conditions involve the effectiveness of the R&D technology, as well as the distribution of the bargaining power between the acquirer and the acquiree, which ...

  2. Unequal-mass galaxy merger remnants: spiral-like morphology but elliptical-like kinematics

    CERN Document Server

    Bournaud, F; Jog, C J

    2004-01-01

    It is generally believed that major galaxy mergers with mass ratios in the range 1:1-3:1 result in remnants that have properties similar to elliptical galaxies, and minor mergers below 10:1 result in disturbed spiral galaxies. The intermediate range of mass ratios 4:1-10:1 has not been studied so far. Using N-body simulations, we show that such mergers can result in very peculiar systems, that have the morphology of a disk galaxy with an exponential profile, but whose kinematics is closer to that of elliptical systems. These objects are similar to those recently observed by Jog & Chitre (2002). We present two cases with mass ratios 4.5:1 and 7:1, and show that the merging causes major heating and results in the appearance of elliptical-type kinematics, while surprisingly the initial spiral-like mass profile is conserved.

  3. Merger-driven evolution of the effective stellar initial mass function of massive early-type galaxies

    Science.gov (United States)

    Sonnenfeld, Alessandro; Nipoti, Carlo; Treu, Tommaso

    2017-02-01

    The stellar initial mass function (IMF) of early-type galaxies is the combination of the IMF of the stellar population formed in situ and that of accreted stellar populations. Using as an observable the effective IMF αIMF, defined as the ratio between the true stellar mass of a galaxy and the stellar mass inferred assuming a Salpeter IMF, we present a theoretical model for its evolution as a result of dry mergers. We use a simple dry-merger evolution model, based on cosmological N-body simulations, together with empirically motivated prescriptions for the IMF to make predictions on how the effective IMF of massive early-type galaxies changes from z = 2 to z = 0. We find that the IMF normalization of individual galaxies becomes lighter with time. At fixed velocity dispersion, αIMF is predicted to be constant with redshift. Current dynamical constraints on the evolution of the IMF are in slight tension with this prediction, even though systematic uncertainties, including the effect of radial gradients in the IMF, prevent a conclusive statement. The correlation of αIMF with stellar mass becomes shallower with time, while the correlation between αIMF and velocity dispersion is mostly preserved by dry mergers. We also find that dry mergers can mix the dependence of the IMF on stellar mass and velocity dispersion, making it challenging to infer, from z = 0 observations of global galactic properties, what is the quantity that is originally coupled with the IMF.

  4. PERANAN KOMPETENSI INTI DALAM MERGER DAN AKUISISI

    Directory of Open Access Journals (Sweden)

    Dwi Sulistiani

    2013-11-01

    Full Text Available Dalam era globalisasi dan pedagangan  bebas dewasa ini strategi merger dan akuisisi  merupakan fenomena yang semakin marak dilakukan oleh para pelaku bisnis dan  semakin menarik untuk dicermati bersama. Untuk menjalankan perusahaan para manajemen perusahaan selalu dituntut menjaga pertumbuhan usahanya secara optimal. Penerapan strategi merger dan akuisisi merupakan jalan pintas untuk mewujudkan pertumbuhan usaha tanpa perusahaan perlu memulai dari awal suatu jenis usaha yang baru. Dalam suatu kondisi perusahaan yang kuat cenderung membeli perusahaan lain untuk meningkatkan daya saing dan penghematan biaya. Perusahaan yang terlibat dalam merger dan akuisisi akan dapat diperoleh pangsa pasar yang lebih besar dan efisiensi terhadap biaya. Perusahaan yang merasa tidak dapat bertahan hidup secara individual biasanya merelakan diri untuk menjadi target akuisisi. Merger dan akuisisi merupakan suatu realitas dan tantangan yang harus siap dihadapi oleh para pelaku usaha dalam era perdagangan bebas saat ini. Namun tingkat kesuksesan dalam melakukan kegiatan merger dan akuisisi juga sangat dipengaruhi oleh kondisi internal perusahaan meliputi sumber daya, kapabilitas dan kompetensi inti yang dimiliki oleh perusahaan. Tulisan ini akan mencoba memberikan pemahaman bahwa sumber daya, kapabilitas dan  kompetensi inti merupakan faktor penting dalam melakukan kegiatan penggabungan usaha yang pada akhirnya dapat menentukan tingkat keberhasilan proses merger dan akuisisi yang sedang dijalankan oleh perusahaan

  5. Studying white dwarf merger remnants with FLASH

    Science.gov (United States)

    Jenks, Malia

    2017-01-01

    There is still uncertainty as to the progenitor systems of type Ia supernova (SN Ia). Both single and double degenerate systems have been suggested as progenitors. In a double degenerate system a merger between the two white dwarfs, with total mass at or exceeding the Chandrasekhar mass, leads to the supernova. If the explosion occurs during the merging process it is a violent merger. If an explosion doesn't occur while the stars merge the system becomes a white dwarf of unstable mass. For mergers of this type with differing starting masses it has been shown that during the viscous evolution carbon burning starts far from the center and stably converts the star to oxygen and neon. In this case the star will eventually collapse to a neutron star and not produce an SN Ia. The case of similar mass mergers has been much less explored. Using the results of a smooth particle hydrodynamic merger we simulate the viscous evolution of models of different mass ratios with FLASH. These simulations test if a similar mass merger can lead to an SN Ia, and begin to probe where the transition from similar to dissimilar mass occurs.

  6. What Drive the Damage to Post-Merger Operating Performance?

    Directory of Open Access Journals (Sweden)

    Soegiharto Soegiharto

    2010-05-01

    Full Text Available This study examines whether bidders’ post-merger operat-ing performance are affected by their CEO behavior, premiumspaid to the target firms, the period of mergers, the method ofpayment, the industry of merged firms, capital liquidity, andtheir pre-merger operating performance. Testing the U.S. suc-cessful merger and acquisition data for the period of 1990s, thisstudy finds that in-wave mergers, intra-industry mergers, thepayment of lower premiums, and better pre-merger operatingperformance drive the bidders to produce better post-mergeroperating performance. Three measures of CEO behavior—themain predictor scrutinezed in this study—are proposed andexamined, and the results demonstrate that the effects of thesemeasures on post-merger operating performance are mixed,suggesting that each of the behavioral measures designed in thisstudy may capture CEO behavior in different ways. Keywords: capital liquidity; CEO overconfidence; merger waves, method of pay-ment operating performance

  7. The rise and fall of stellar discs across the peak of cosmic star formation history: mergers versus smooth accretion

    CERN Document Server

    Welker, Charlotte; Devriendt, Julien; Pichon, Christophe; Kaviraj, Sugata; Peirani, Sebastien

    2015-01-01

    Building galaxy merger trees from a state-of-the-art cosmological hydrodynamics simulation, Horizon-AGN, we perform a statistical study of how mergers and smooth accretion drive galaxy morphologic properties above $z > 1$. More specifically, we investigate how stellar densities, effective radii and shape parameters derived from the inertia tensor depend on mergers of different mass ratios. We find strong evidence that smooth accretion tends to flatten small galaxies over cosmic time, leading to the formation of disks. On the other hand, mergers, and not only the major ones, exhibit a propensity to puff up and destroy stellar disks, confirming the origin of elliptical galaxies. We also find that elliptical galaxies are more susceptible to grow in size through mergers than disc galaxies with a size-mass evolution $r \\prop M^{1.2}$ instead of $r \\prop M^{-0.5} - M^{0.5}$ depending on the merger mass ratio. The gas content drive the size-mass evolution due to merger with a faster size growth for gas-poor galaxies...

  8. Binary neutron star merger simulations

    Energy Technology Data Exchange (ETDEWEB)

    Bruegmann, Bernd [Jena Univ. (Germany)

    2016-11-01

    Our research focuses on the numerical tools necessary to solve Einstein's equations. In recent years we have been particularly interested in spacetimes consisting of two neutron stars in the final stages of their evolution. Because of the emission of gravitational radiation, the objects are driven together to merge; the emitted gravitational wave signal is visualized. This emitted gravitational radiation carries energy and momentum away from the system and contains information about the system. Late last year the Laser Interferometer Gravitational-wave Observatory (LIGO) began searches for these gravitational wave signals at a sensitivity at which detections are expected. Although such systems can radiate a significant amount of their total mass-energy in gravitational waves, the gravitational wave signals one expects to receive on Earth are not strong, since sources of gravitational waves are often many millions of light years away. Therefore one needs accurate templates for the radiation one expects from such systems in order to be able to extract them out of the detector's noise. Although analytical models exist for compact binary systems when the constituents are well separated, we need numerical simulation to investigate the last orbits before merger to obtain accurate templates and validate analytical approximations. Due to the strong nonlinearity of the equations and the large separation of length scales, these simulations are computationally demanding and need to be run on large supercomputers. When matter is present the computational cost as compared to pure black hole (vacuum) simulations increases even more due to the additional matter fields. But also more interesting astrophysical phenomena can happen. In fact, there is the possibility for a strong electromagnetic signal from the merger (e.g., a short gamma-ray burst or lower-energy electromagnetic signatures from the ejecta) and significant neutrino emission. Additionally, we can expect that

  9. The challenge of merging : Merger patterns, premerger status, and merger support

    NARCIS (Netherlands)

    Giessner, [No Value; Täuber, Susanne; Viki, GT; Otten, S; Terry, DJ; Giessner, S.R

    2006-01-01

    Employees of merging organizations often show resistance to the merger. The employees' support depends on the companies' premerger status and on the merger pattern. Based on an inter-group perspective, three studies were conducted to investigate the influence of premerger status (high, low) and merg

  10. When Mergers Fail: A Case Study on the Critical Role of External Stakeholders in Merger Initiatives

    Science.gov (United States)

    Stensaker, Bjørn; Persson, Mats; Pinheiro, Rómulo

    2016-01-01

    One can, in principle, identify numerous arguments for mergers in higher education (HE), including efficiency, diversity, quality, and regional needs. This diversity can be explained by the growing societal interest in the sector, not least concerning the contributions from HE to society at large. However, research on merger processes has tended…

  11. Mergers in health care: avoiding divorce IDS style.

    Science.gov (United States)

    Drazen, E; Kueber, M

    1998-08-01

    The recent flurry of merger activity in the healthcare industry has given rise to a significant number of integration efforts. Unfortunately, some of these "marriages" will end in "divorce." Reasons for failure can be found in four critical dimensions of integration: structural, operational, clinical, and informational. Each dimension has its associated pitfalls, and every merger confronts clearly identifiable risks. By taking steps to mitigate such risks, merging organizations can improve the chances the merger will succeed. If the merger does fail, measures taken prior to the merger, such as including an escape clause in the merger contract, can help avoid problems in dividing operational assets, physicians practices, and information assets.

  12. Employees' responses to an organizational merger: Intraindividual change in organizational identification, attachment, and turnover.

    Science.gov (United States)

    Sung, Wookje; Woehler, Meredith L; Fagan, Jesse M; Grosser, Travis J; Floyd, Theresa M; Labianca, Giuseppe Joe

    2017-06-01

    The authors used pre-post merger data from 599 employees experiencing a major corporate merger to compare 3 conceptual models based on the logic of social identity theory (SIT) and exchange theory to explain employees' merger responses. At issue is how perceived change in employees' own jobs and roles (i.e., personal valence) and perceived change in their organization's status and merger appropriateness (i.e., organizational valence) affect their changing organizational identification, attachment attitudes, and voluntary turnover. The first model suggests that organizational identification and organizational attachment develop independently and have distinct antecedents. The second model posits that organizational identification mediates the relationships between change in organizational and personal valence and change in attachment and turnover. The third model posits that change in personal valence moderates the relationship between changes in organizational valence and in organizational identification and attachment. Using latent difference score (LDS) modeling in an SEM framework and survival analysis, the results suggest an emergent fourth model that integrates the first and second models: Although change in organizational identification during the merger mediates the relationship between change in personal status and organizational valence and change in attachment, there is a direct and unmediated relationship between change in personal valence and attachment. This integrated model has implications for M&A theory and practice. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. The Effects of Gas on Morphological Transformation in Mergers: Implications for Bulge and Disk Demographics

    CERN Document Server

    Hopkins, Philip F; Cox, Thomas J; Hernquist, Lars; Jogee, Shardha; Keres, Dusan; Ma, Chung-Pei; Robertson, Brant; Stewart, Kyle

    2009-01-01

    Transformation of disks into spheroids via mergers is a well-accepted element of galaxy formation models. However, recent simulations have shown that bulge formation is suppressed in increasingly gas-rich mergers. We investigate the global implications of these results in a cosmological framework, using independent approaches: empirical halo-occupation models (where galaxies are populated in halos according to observations) and semi-analytic models. In both, ignoring the effects of gas in mergers leads to the well-known over-production of spheroids at low masses: low and intermediate-mass galaxies are inescapably predicted to be bulge-dominated (B/T~0.5 at <10^10 M_sun, with almost no 'bulgeless' systems), even if they have avoided major mergers. Including the different physical behavior of gas in mergers immediately leads to a dramatic change: bulge formation is suppressed in low-mass galaxies, which are observed to be gas-rich (giving B/T~0.1 at <10^10 M_sun, with a number of bulgeless galaxies in goo...

  14. Dark matter halo merger and accretion probabilities in the excursion set formalism

    CERN Document Server

    Alizadeh, Esfandiar

    2008-01-01

    The merger and accretion probabilities of dark matter halos have so far only been calculated for an infinitesimal time interval. This means that a Monte-Carlo simulation with very small time steps is necessary to find the merger history of a parent halo. In this paper we use the random walk formalism to find the merger and accretion probabilities of halos for a finite time interval. Specifically, we find the number density of halos at an early redshift that will become part of a halo with a specified final mass at a later redshift, given that they underwent $n$ major mergers, $n=0,1,2,...$ . We reduce the problem into an integral equation which we then solve numerically. To ensure the consistency of our formalism we compare the results with Monte-Carlo simulations and find very good agreement. Though we have done our calculation assuming a flat barrier, the more general case can easily be handled using our method. This derivation of finite time merger and accretion probabilities can be used to make more effic...

  15. Massive black hole binary mergers within sub-pc scale gas discs

    CERN Document Server

    Cuadra, J; Alexander, R D; Begelman, M C

    2008-01-01

    [ABRIDGED] We study supermassive black hole binary mergers driven by angular momentum loss to small-scale gas discs. Such binaries form after major galaxy mergers, but their fate is unclear since hardening through stellar scattering becomes very inefficient at sub-parsec distances. Gas discs may dominate binary dynamics on these scales, and promote mergers. Using numerical simulations, we investigate the evolution of the orbits of binaries embedded within geometrically thin gas discs. Our simulations directly resolve angular momentum transport within the disc, which at the radii of interest is likely dominated by disc self-gravity. We show that the binary decays at a rate which is in good agreement with analytical estimates, while the eccentricity grows. Saturation of eccentricity growth is not observed up to values e > 0.35. Accretion onto the black holes is variable, and is roughly modulated by the binary orbital frequency. Scaling our results, we analytically estimate the maximum rate of binary decay that ...

  16. Binary Black Hole Mergers from Globular Clusters: Implications for Advanced LIGO.

    Science.gov (United States)

    Rodriguez, Carl L; Morscher, Meagan; Pattabiraman, Bharath; Chatterjee, Sourav; Haster, Carl-Johan; Rasio, Frederic A

    2015-07-31

    The predicted rate of binary black hole mergers from galactic fields can vary over several orders of magnitude and is extremely sensitive to the assumptions of stellar evolution. But in dense stellar environments such as globular clusters, binary black holes form by well-understood gravitational interactions. In this Letter, we study the formation of black hole binaries in an extensive collection of realistic globular cluster models. By comparing these models to observed Milky Way and extragalactic globular clusters, we find that the mergers of dynamically formed binaries could be detected at a rate of ∼100 per year, potentially dominating the binary black hole merger rate. We also find that a majority of cluster-formed binaries are more massive than their field-formed counterparts, suggesting that Advanced LIGO could identify certain binaries as originating from dense stellar environments.

  17. DISCOVERY OF A DISSOCIATIVE GALAXY CLUSTER MERGER WITH LARGE PHYSICAL SEPARATION

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, William A.; Wittman, David; Jee, M. James; Gee, Perry; Tyson, J. Anthony; Schmidt, Samuel; Thorman, Paul; Bradac, Marusa; Lemaux, Brian [Department of Physics, University of California, Davis, One Shields Av., Davis, CA 95616 (United States); Hughes, John P. [Department of Physics and Astronomy, Rutgers University, 136 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States); Miyazaki, Satoshi; Utsumi, Yousuke [Department of Astronomical Science, The Graduate University for Advanced Studies, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Margoniner, Vera E., E-mail: wadawson@ucdavis.edu [Department of Physics and Astronomy, California State University, Sacramento, 6000 J Street Sacramento, CA 95819 (United States)

    2012-03-10

    We present DLSCL J0916.2+2951 (z = 0.53), a newly discovered major cluster merger in which the collisional cluster gas has become dissociated from the collisionless galaxies and dark matter (DM). We identified the cluster using optical and weak-lensing observations as part of the Deep Lens Survey. Our follow-up observations with Keck, Subaru, Hubble Space Telescope, and Chandra show that the cluster is a dissociative merger and constrain the DM self-interaction cross-section {sigma}{sub DM} m{sup -1}{sub DM} {approx}< 7 cm{sup 2} g{sup -1}. The system is observed at least 0.7 {+-} 0.2 Gyr since first pass-through, thus providing a picture of cluster mergers 2-5 times further progressed than similar systems observed to date. This improved temporal leverage has implications for our understanding of merging clusters and their impact on galaxy evolution.

  18. The Most Bound Halo Particle-Galaxy Correspondence Model: Comparison between Models with Different Merger Timescales

    CERN Document Server

    Hong, Sungwook E; Kim, Juhan

    2016-01-01

    We develop a galaxy assignment scheme that populates dark matter halos with galaxies by tracing the most bound member particles (MBPs) of simulated halos. Several merger-timescale models based on analytic calculations and numerical simulations are adopted as the survival time of mock satellite galaxies. We build mock galaxy samples from halo merger data of the Horizon Run 4 $N$-body simulation from $z = 12-0$. We compare group properties and two-point correlation functions (2pCFs) of mock galaxies with those of volume-limited SDSS galaxies, with $r$-band absolute magnitudes of $\\mathcal{M}_r - 5 \\log h 10^{14} h^{-1} M_{\\odot}$) and the small-scale 2pCF ($r_{\\rm p} < 10 h^{-1} {\\rm Mpc}$) quite well for the majority of the merger timescale models adopted. The new scheme outperforms the previous subhalo-galaxy correspondence scheme by more than $2\\sigma$.

  19. Growth of Supermassive Black Holes, Galaxy Mergers and Supermassive Binary Black Holes

    Science.gov (United States)

    Komossa, S.; Baker, J. G.; Liu, F. K.

    The study of galaxy mergers and supermassive binary black holes (SMBBHs) is central to our understanding of the galaxy and black hole assembly and (co-)evolution at the epoch of structure formation and throughout cosmic history. Galaxy mergers are the sites of major accretion episodes, they power quasars, grow supermassive black holes (SMBHs), and drive SMBH-host scaling relations. The coalescing SMBBHs at their centers are the loudest sources of gravitational waves (GWs) in the Universe, and the subsequent GW recoil has a variety of potential astrophysical implications which are still under exploration. Future GW astronomy will open a completely new window on structure formation and galaxy mergers, including the direct detection of coalescing SMBBHs, high-precision measurements of their masses and spins, and constraints on BH formation and evolution in the high-redshift Universe.

  20. Growth of supermassive black holes, galaxy mergers and supermassive binary black holes

    CERN Document Server

    Komossa, S; Liu, F K

    2016-01-01

    The study of galaxy mergers and supermassive binary black holes (SMBBHs) is central to our understanding of the galaxy and black hole assembly and (co-)evolution at the epoch of structure formation and throughout cosmic history. Galaxy mergers are the sites of major accretion episodes, they power quasars, grow supermassive black holes (SMBHs), and drive SMBH-host scaling relations. The coalescing SMBBHs at their centers are the loudest sources of gravitational waves (GWs) in the universe, and the subsequent GW recoil has a variety of potential astrophysical implications which are still under exploration. Future GW astronomy will open a completely new window on structure formation and galaxy mergers, including the direct detection of coalescing SMBBHs, high-precision measurements of their masses and spins, and constraints on BH formation and evolution in the high-redshift universe.

  1. Staff perceptions of the merger between two South African regional ...

    African Journals Online (AJOL)

    perceptions on the impact of the merger on quality and standards of education were also ... However, significant positive factors identified in the study include intrinsically motivated staff and a consensus in support of merger objectives and

  2. PERLINDUNGAN HUKUM TERHADAP KEPENTINGAN PARA PIHAK DI DALAM MERGER BANK

    Directory of Open Access Journals (Sweden)

    Dani Amran Hakim

    2016-04-01

    Full Text Available The legal protection of interests of the parties in the merger of banks, which is formulated into the problem as follows a Is the legal basis for bank mergers? b How is the legal protection of the parties in a bank merger? Merger is one of the company's development and growth. Merger is also one other alternative for capital investment through internal and organic growth. In banking mergers regulated in Law Number 10 of 1998. In the implementation of the merger must also consider the interests of the parties, namely, 1 the interests of the shareholders, 2 the interests of the depositors, 3 the interest of the bank employees, and 4 the interests of officials. Keywords: Protection Law, the Parties, Bank Merger 

  3. THE TYPOLOGY OF REGIONAL MERGERS FROM THE PERSPECTIVE OF FINANCIAL-ACCOUNTING ASPECTS

    Directory of Open Access Journals (Sweden)

    RACHISAN PAULA RAMONA

    2011-12-01

    Full Text Available The interest for approaching this paper is determined by the actuality of the theme concerning mergers, and also by the scale proportions this type of transactions have arrived at, both at global level and also at national level, everything having as cornerstone a market economy within which competitiveness plays a more and more important role. The aim of the study consists in analyzing the external restructuring of entities under the form of mergers. On one side, in order to clarify and deepen the theoretical aspects concerning mergers, and on the other side, in order to identify certain features related to merger transactions in Cluj County. The aim of the study is to identify the conditions and manner of merger development within commercial entities from Cluj County and to establish a typology relying on the results concerning the relationship between the entities shareholding structure, their contribution and the exchange ratio when performing the transactions. The actuality of the theme, the requirement and the increasing manifestation of the merger phenomenon also within the Romanian teritory, the necessity of a thorough analysis of merger trends and typologies, they all have been trigger factors of this objective. In order to achieve the objective a research methodology was followed, assumptions were made, which have been confirmed of infirmed. The methodological sphere consists of an approach of considered quantitative and qualitative models, of techniques for data collection, hypotheses testing, but also of research boundaries. As a result of the processing and analysis of the data on which this study relies, one arrived to the following conclusions concerning mergers that were performed in Cluj County, conclusions which could lead to the elaboration of a typology for the mergers that have occurred in this region: in terms of shareholding structure, the two entities usually had a joint majority shareholder, and regarding the financial

  4. EUROPEAN CROSS-BORDER MERGERS AND ACQUISITIONS- REALITIES AND PERSPECTIVES

    OpenAIRE

    Vancea Mariana

    2011-01-01

    This paper analyses the impact of the economic and financial crisis on merger and acquisition activity in Europe and the latest trends manifested on the cross-border merger and acquisition market involving European companies. Thus, a first objective of this research is to reveal the evolution of the European cross-border merger and acquisition activity in terms of dynamics, volume and structure. Another objective of this research is to reveal the short and medium term perspectives on mergers ...

  5. A Risk Management Model for Merger and Acquisition

    OpenAIRE

    Chui, B. S.

    2011-01-01

    In this paper, a merger and acquisition risk management model is proposed for considering risk factors in the merger and acquisition activities. The proposed model aims to maximize the probability of success in merger and acquisition activities by managing and reducing the associated risks. The modeling of the proposed merger and acquisition risk management model is described and illustrated in this paper. The illustration result shows that the proposed model can help to screen the best targe...

  6. Analysis of International Mergers and Acquisitions in the Pharmaceutical Industry

    OpenAIRE

    Božo Matić; Vlatka Bilas; Vedran Bači

    2011-01-01

    There are numerous researches which analyze mergers and acquisitions, but most of them do not focus on a certain industry, but their sample considers companies from different industries. This paper focuses on mergers and acquisitions in the pharmaceutical industry. It is assumed that pharmaceutical companies with no experience in mergers and acquisitions achieve better results in relatively small and domestic mergers and acquisitions while pharmaceutical companies with greater exp...

  7. Gravitational Fragmentation in Galaxy Mergers: A Stability Criteria

    CERN Document Server

    Escala, Andres; del Valle, Luciano; Castillo, Esteban

    2012-01-01

    We study the gravitational stability of gaseous streams in the complex environment of a galaxy merger, because mergers are known to be places of ongoing massive cluster formation and bursts of star formation. We find an analytic stability parameter for case of gaseous streams orbiting around the merger remnant. We test our stability criteria using hydrodynamical simulations of galaxy mergers, obtaining satisfactory results. We find that our criteria successfully predicts the streams that will be gravitationally unstable to fragment into clumps.

  8. Life extinctions by neutron star mergers

    CERN Document Server

    Dar, Arnon; Shaviv, N J; Dar, Arnon; Laor, Ari; Shaviv, Nir J.

    1997-01-01

    High energy cosmic ray jets from nearby mergers or accretion induced collapse (AIC) of neutron stars (NS) that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer and radioactivate the environment. They could have caused most of the massive life extinctions on planet Earth in the past 600 My. Biological mutations due to ionizing radiations could have caused the fast appearance of new species after the massive extinctions. An early warning of future extinctions due to NS mergers may be obtained by identifying, mapping and timing all the nearby binary neutron stars systems. A warning of an approaching cosmic ray burst from a nearby NS merger/AIC may be provided by a very intense gamma ray burst which preceeds it.

  9. The Fate of Neutron Star Binary Mergers

    Science.gov (United States)

    Piro, Anthony L.; Giacomazzo, Bruno; Perna, Rosalba

    2017-08-01

    Following merger, a neutron star (NS) binary can produce roughly one of three different outcomes: (1) a stable NS, (2) a black hole (BH), or (3) a supramassive, rotationally supported NS, which then collapses to a BH following angular momentum losses. Which of these fates occur and in what proportion has important implications for the electromagnetic transient associated with the mergers and the expected gravitational wave (GW) signatures, which in turn depend on the high density equation of state (EOS). Here we combine relativistic calculations of NS masses using realistic EOSs with Monte Carlo population synthesis based on the mass distribution of NS binaries in our Galaxy to predict the distribution of fates expected. For many EOSs, a significant fraction of the remnants are NSs or supramassive NSs. This lends support to scenarios in which a quickly spinning, highly magnetized NS may be powering an electromagnetic transient. This also indicates that it will be important for future GW observatories to focus on high frequencies to study the post-merger GW emission. Even in cases where individual GW events are too low in signal to noise to study the post merger signature in detail, the statistics of how many mergers produce NSs versus BHs can be compared with our work to constrain the EOS. To match short gamma-ray-burst (SGRB) X-ray afterglow statistics, we find that the stiffest EOSs are ruled out. Furthermore, many popular EOSs require a significant fraction of ˜60%-70% of SGRBs to be from NS-BH mergers rather than just binary NSs.

  10. A Dynamic Model of Endogenous Mergers and Trade Liberalization

    NARCIS (Netherlands)

    Ray Chaudhuri, A.

    2008-01-01

    This paper uses a dynamic dominant-firm model with an endogenous merger process to examine the effects of trade liberalization on industry structure. Domestic and cross-border mergers and demergers are allowed for. When firms are myopic and the dominant firm has a sufficiently high pre-merger capita

  11. Gravitational waves from neutron-star mergers

    Science.gov (United States)

    Read, Jocelyn; Cullen, Torrey; Flynn, Eric; Lockett-Ruiz, Veronica; Park, Conner; Vong, Susan

    2016-03-01

    The inspiral and merger of binary neutron stars is expected to provide many signals for Advanced LIGO at design sensitivity. The waveform models currently used to search for and parameterize these signals ignore effects near the merger: as the stars coalesce, the gravitational waves depend additionally on the properties of matter in the core of the stars. In this talk, I will discuss potential systematic error from neglecting these features and present phenomenological waveform models currently being developed to capture the dynamics of merging neutron stars.

  12. The Carnegie-Irvine Galaxy Survey. IV. A Method to Determine the Average Mass Ratio of Mergers That Built Massive Elliptical Galaxies

    CERN Document Server

    Huang, Song; Peng, Chien Y; Li, Zhao-Yu; Barth, Aaron J

    2016-01-01

    Many recent observations and numerical simulations suggest that nearby massive, early-type galaxies were formed through a "two-phase" process. In the proposed second phase, the extended stellar envelope was accumulated through many dry mergers. However, details of the past merger history of present-day ellipticals, such as the typical merger mass ratio, are difficult to constrain observationally. Within the context and assumptions of the two-phase formation scenario, we propose a straightforward method, using photometric data alone, to estimate the average mass ratio of mergers that contributed to the build-up of massive elliptical galaxies. We study a sample of nearby massive elliptical galaxies selected from the Carnegie-Irvine Galaxy Survey, using two-dimensional analysis to decompose their light distribution into an inner, denser component plus an extended, outer envelope, each having a different optical color. The combination of these two substructures accurately recovers the negative color gradient exhi...

  13. The determinants of merger waves: An international perspective

    Science.gov (United States)

    Gugler, Klaus; Mueller, Dennis C.; Weichselbaumer, Michael

    2012-01-01

    One of the most conspicuous features of mergers is that they come in waves that are correlated with increases in share prices and price/earnings ratios. We use a natural way to discriminate between pure stock market influences on firm decisions and other influences by examining merger patterns for both listed and unlisted firms. If “real” changes in the economy drive merger waves, as some neoclassical theories of mergers predict, both listed and unlisted firms should experience waves. We find significant differences between listed and unlisted firms as predicted by behavioral theories of merger waves. PMID:27346903

  14. A Risk Management Model for Merger and Acquisition

    Directory of Open Access Journals (Sweden)

    B. S. Chui

    2011-05-01

    Full Text Available In this paper, a merger and acquisition risk management model is proposed for considering risk factors in the merger and acquisition activities. The proposed model aims to maximize the probability of success in merger and acquisition activities by managing and reducing the associated risks. The modeling of the proposed merger and acquisition risk management model is described and illustrated in this paper. The illustration result shows that the proposed model can help to screen the best target company with minimum associated risks in the merger and acquisition activity.

  15. Impact of faecal DM excretion on faecal calcium losses in dogs eating complete moist and dry pet foods - food digestibility is a major determinant of calcium requirements.

    Science.gov (United States)

    Kienzle, Ellen; Brenten, Thomas; Dobenecker, Britta

    2017-01-01

    The recommendations for the Ca supply for maintenance of dogs have been reduced by about 75 % in the last decades. An important factor for Ca requirements is faecal Ca losses. In previous studies with experimental diets faecal Ca losses depended on Ca intake and on faecal DM excretion. A predictive equation for faecal Ca losses in mg/kg body weight (BW) developed in a fibre model is: faecal losses = -33·8 + (13·6 faecal DM excretion (g/kg BW)) + (0·78 Ca intake (mg/kg BW)). The present study aimed at testing this equation in pet food with material from trials carried out for other purposes. Digestion trials with twenty-five dry and fifteen moist foods (326 observations in total) were evaluated retrospectively. Faecal DM excretion and faecal Ca losses were significantly correlated (r(2) 0·86; P food. Faecal DM excretion has a considerable impact on faecal Ca losses in a practical feeding situation. In conclusion, Ca requirements for maintenance may vary with food DM intake and digestibility.

  16. BANK MERGERS AND ACQUISITIONS IN ROMANIA AFTER 1989

    Directory of Open Access Journals (Sweden)

    Copil Crina Angela

    2014-07-01

    have a special purpose, they are necessary operations of draining the bank life by the absorption of the banks without stability by those with potential of economical and managerial stable capital. It is well known that the great banks, very strong and well consolidated created in the process of mergers and acquisitions have another potential in maintenance of the flux of profit and the balanced increase of the profitableness, having a great impact on the economy. The contribution consists in combining some conceptual elements with some empirical aspects, with the process of bank concentration created by acquisitions and fusions that leads to the elimination of some bank entitites that are not credible and stable and maintenance of those that are efficient, useful and credible for the client and for the Romanian society. The subject is a present one in the entire world, in a continuous change and adapting to the existent tendencies in the entire world, having a major impact also on the Romanian bank market, on the bank financial institutions that in order to face the competition have directed their strategies for the diversification of the risks.

  17. Mergers and alliances the wider view

    CERN Document Server

    Woodsworth, Anne

    2013-01-01

    Volume 36 of Advances in Librarianship seeks to provide a broad review of the factors that lead to mergers and other alliances, the methods used to ensure effective and successful collaborations, and descriptions of the factors which contributed to less successful efforts at consolidation.

  18. Technology-based Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan; Moini, Hamid

    2014-01-01

    The purpose of this chapter is to provide an updated review of what is known about the performance of technology-based mergers and acquisitions (TBM&As) and their determinants. This review brings together papers published from 1990 to 2012 in top-rated academic journals within nearly all fields...

  19. Corporate Employee-Engagement and Merger Outcomes

    NARCIS (Netherlands)

    Liang, H.; Renneboog, Luc

    2017-01-01

    Extending the theories of employee incentives and inalienability of human capital, we investigate the link between a firm’s engagement in employee issues and the returns to shareholders around mergers and acquisitions (M&As) and analyze an international sample of 4,565 M&A deals from 48 countries. W

  20. Corporate Employee-Engagement and Merger Outcomes

    NARCIS (Netherlands)

    Liang, H.; Renneboog, Luc

    2017-01-01

    Extending the theories of employee incentives and inalienability of human capital, we investigate the link between a firm’s engagement in employee issues and the returns to shareholders around mergers and acquisitions (M&As) and analyze an international sample of 4,565 M&A deals from 48 countries.

  1. Can the "Merger" Emerge with Multiple Identities?

    Science.gov (United States)

    Louden, Allan

    This paper considers the future of the National Debate Tournament (NDT)/Cross Examination Debate Association (CEDA) merger from a historical perspective. The paper speculates on "natural rhythms" of organizations for perpetuation and attenuation. Specifically, it explores the historical growth and retrenchment of Delta Sigma Rho (DSR)/Tau Kappa…

  2. Merger and Acquisition in the Banking Sector

    Directory of Open Access Journals (Sweden)

    Anna Szewczyk

    2008-12-01

    Full Text Available The article presents situation on mergers and acquisitions (MA in banking sector during last twenty years. The main motives are selected and analyzed. All is explained on the base on research reports of the Deutsche Bundesbank and the European Central Bank.

  3. Merger incentives and the failing firm defense

    NARCIS (Netherlands)

    Bouckaert, J.M.C.; Kort, P.M.

    2014-01-01

    The merger incentives between profitable firms differ fundamentally from the incentives of a profitable firm to merge with a failing firm. We investigate these incentives under different modes of price competition and Cournot behavior. Our main finding is that firms strictly prefer exit of the faili

  4. Cross-border Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan

    This paper focuses on three topics in cross-border mergers and acquisitions (CBM&As) field: motivations for CBM&As, valuation techniques and CBM&A performance (assessment and the determinants). By taking an overview of what have been found so far in academic field and investigating...

  5. Merger incentives and the failing firm defense

    NARCIS (Netherlands)

    Bouckaert, J.M.C.; Kort, P.M.

    2014-01-01

    The merger incentives between profitable firms differ fundamentally from the incentives of a profitable firm to merge with a failing firm. We investigate these incentives under different modes of price competition and Cournot behavior. Our main finding is that firms strictly prefer exit of the

  6. Corporate Employee-Engagement and Merger Outcomes

    NARCIS (Netherlands)

    Liang, H.; Renneboog, Luc

    2017-01-01

    Extending the theories of employee incentives and inalienability of human capital, we investigate the link between a firm’s engagement in employee issues and the returns to shareholders around mergers and acquisitions (M&As) and analyze an international sample of 4,565 M&A deals from 48 countries. W

  7. V1309 SCO - Understanding a merger

    CERN Document Server

    Nandez, Jose L A; Lombardi, James

    2013-01-01

    One of the two outcomes of a common envelope event is a merger of the two stars. To date, the best known case of a binary merger is the V1309 Sco outburst, where the orbital period was known and observed to decay up to the outburst. Using the hydrodynamical code StarSmasher, we study in detail which characteristics of the progenitor binary affect the outburst and produce the best match with observations. We consider binaries consisting of a 1.52 $M_\\odot$ giant and a 0.16 $M_\\odot$ companion with an orbital period of 1.4 days, varying the nature of the companion (main-sequence or white dwarf star) and the rotation of the donor. We show that all considered progenitor binaries evolve towards the merger primarily due to the Darwin instability. While the binary system merges into a single object, the merger is accompanied by mass ejection that proceeds in several separate mass outbursts and takes away a few percent of the donor mass. This very small mass nonetheless is important as it is not only sufficient to ex...

  8. Identity management key to successful mergers

    NARCIS (Netherlands)

    S.R. Giessner (Steffen)

    2011-01-01

    textabstractAlienated employees who feel a loss of identity could place financial and strategic objectives of a merger at risk through lack of drive, reduced performance, and even sabotage. Identifying and managing these issues from the start could therefore be critical to the success of such undert

  9. Binary Black Holes: Mergers, Dynamics, and Waveforms

    Science.gov (United States)

    Centrella, Joan

    2007-04-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.

  10. Mergers and acquisitions involving equine veterinary practices.

    Science.gov (United States)

    Jackman, Brad R; McCafferty, Owen E

    2009-12-01

    This article discusses mergers and acquisitions involving equine veterinary practices. Combining practices can be professionally and economically advantageous but requires a great deal of thought, planning, and implementation. If due diligence is performed and true business teamwork is undertaken, the benefits can be enormous and rewarding.

  11. Cross-border Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan

    This paper focuses on three topics in cross-border mergers and acquisitions (CBM&As) field: motivations for CBM&As, valuation techniques and CBM&A performance (assessment and the determinants). By taking an overview of what have been found so far in academic field and investigating...

  12. Technology-based Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Wang, Daojuan; Moini, Hamid

    2014-01-01

    The purpose of this chapter is to provide an updated review of what is known about the performance of technology-based mergers and acquisitions (TBM&As) and their determinants. This review brings together papers published from 1990 to 2012 in top-rated academic journals within nearly all fields...

  13. The Arp 220 merger on kpc scales

    CERN Document Server

    König, S; Eckart, A; Downes, D; Scharwächter, J

    2012-01-01

    For the first time we study the Eastern nucleus in greater detail and search for the more extended emission in the molecular gas in different CO line transitions of the famous ULIRG Arp 220. Furthermore we present a model of the merger in Arp 220 on large scales with the help of the CO data and an optical and near-infrared composite HST image of the prototypical ULIRG. Using the Plateau de Bure Interferometer (PdBI) we obtained CO(2-1) and (1-0) data at wavelengths of 1 and 3 mm in 1994, 1996, 1997 and 2006 at different beam sizes and spatial resolutions. The simulations of the merger in Arp 220 were performed with the Identikit modeling tool. The model parameters that describe the galaxy merger best give a mass ratio of 1:2 and result in a merger of ~6x10^8 yrs. The low resolution CO(1-0) PdBI observations suggest that there are indications for emission ~10" towards the south, as well as to the north and to the west of the two nuclei.

  14. THE Arp 220 MERGER ON kpc SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, S. [Dark Cosmology Centre, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Garcia-Marin, M.; Eckart, A. [I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Strasse 77, D-50937 Koeln (Germany); Downes, D. [Institut de Radioastronomie Millimetrique, Domaine Universitaire, F-38406 St. Martin d' Heres (France); Scharwaechter, J., E-mail: skoenig@dark-cosmology.dk [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia)

    2012-07-20

    For the first time, we study the eastern nucleus in greater detail and search for the more extended emission in the molecular gas in different CO line transitions of the famous ultraluminous infrared galaxy (ULIRG) Arp 220. Furthermore, we present a model of the merger in Arp 220 on large scales with the help of the CO data and an optical and near-infrared composite Hubble Space Telescope image of the prototypical ULIRG. Using the Plateau de Bure interferometer (PdBI), we obtained CO (2-1) and (1-0) data at wavelengths of 1 and 3 mm in 1994, 1996, 1997, and 2006 at different beam sizes and spatial resolutions. The simulations of the merger in Arp 220 were performed with the Identikit modeling tool. The model parameters that describe the galaxy merger best give a mass ratio of 1:2 and result in a merger of {approx}6 Multiplication-Sign 10{sup 8} yr. The low-resolution CO (1-0) PdBI observations suggest that there are indications for emission {approx}10'' toward the south, as well as to the north and to the west of the two nuclei.

  15. DO ROMANIAN MERGERS REALLY CREATE VALUE?

    Directory of Open Access Journals (Sweden)

    Anca-Simona HROMEI

    2015-12-01

    Full Text Available The realities of our modern society demonstrate that businesses operate in a competitive environment, which requires continuous improvement and development of production and sales. In this context, for financial, economic and fiscal reasons, companies resort to a process of concentration, through the merger of all the factors involved in the fulfilment and diversification of their activities. Often, the reasons for engaging in a merger refer to the fact that two merged companies create, in terms of value, an entity that exceeds the individual values of the two participants if they were to continue to activate separately. This paper aims at analysing whether the well-known relationship ‘1+1=3’, which describes merger synergies, applies at the Romanian level. For this reason, each of the values of 77 merged companies were compared with the sum of the individual values of the firms that initially created them. It was found that 56% of the mergers analysed generated added value for shareholders.

  16. Galaxy Zoo: Multi-Mergers and the Millennium Simulation

    CERN Document Server

    Darg, D W; Lintott, C J; Schawinski, K; Silk, J; Lynn, S; Bamford, S; Nichol, R C

    2010-01-01

    We present a catalogue of 39 multiple-mergers found using the mergers catalogue of the Galaxy Zoo project for $z<0.1$ and compare them to corresponding semi-analytical galaxies from the Millennium Simulation. We estimate the (volume-limited) multi-merger fraction of the local Universe using our sample and find it to be at least two orders of magnitude less than binary-mergers - in good agreement with the simulations (especially the Munich group). We then investigate the properties of galaxies in binary- and multi-mergers (morphologies, colours, stellar masses and environment) and compare these results with those predicted by the semi-analytical galaxies. We find that multi-mergers favour galaxies with properties typical of elliptical morphologies and that this is in qualitative agreement with the models. Studies of multi-mergers thus provide an independent (and largely corroborating) test of the Millennium semi-analytical models.

  17. Black Hole Mergers as Probes of Structure Formation

    Science.gov (United States)

    Alicea-Munoz, Emily

    2008-01-01

    Observations of gravitational waves from massive black hole (MBH) mergers can provide us with important clues about the era of structure formation in the early universe. Previous research in this field has been limited to calculating merger rates of MBHs using different models where many assumptions are made about the specific values of physical parameters of the mergers, resulting in merger rate estimates that span 5 to 6 orders of magnitude. We develop a semi-analytical, phenomenological model that includes plausible combinations of several physical parameters involved in the mergers. which we then turn around to determine how well LISA observations will be able to enhance our understanding of the universe during the critical z approximately equal to 5-30 structure formation era. We do this by generating synthetic LISA observable data (masses, redshifts, merger rates), which are then analyzed using a Markov Chain Monte Carlo (MCMC) method. This allows us to constrain the physical parameters of the mergers.

  18. Formation of S0 galaxies through mergers: Explaining angular momentum and concentration change from spirals to S0s

    CERN Document Server

    Querejeta, Miguel; Tapia, Trinidad; Borlaff, Alejandro; van de Ven, Glenn; Lyubenova, Mariya; Martig, Marie; Falcón-Barroso, Jesús; Méndez-Abreu, Jairo

    2015-01-01

    The CALIFA team has recently found that the stellar angular momentum and concentration of late-type spiral galaxies are incompatible with those of lenticular galaxies (S0s), concluding that fading alone cannot satisfactorily explain the evolution from spirals into S0s. Here we explore whether major mergers can provide an alternative way to transform spirals into S0s by analysing the spiral-spiral major mergers from the GalMer database that lead to realistic, relaxed S0-like galaxies. We find that the change in stellar angular momentum and concentration can explain the differences in the $\\lambda_\\mathrm{Re}$--$R_{90}/R_{50}$ plane found by the CALIFA team. Major mergers thus offer a feasible explanation for the transformation of spirals into S0s.

  19. Massive Close Pairs Measure Rapid Galaxy Assembly in Mergers at High Redshift

    CERN Document Server

    Snyder, Gregory F; Rodriguez-Gomez, Vicente; Guimaraes, Renato da Silva; Torrey, Paul; Hernquist, Lars

    2016-01-01

    We compare mass-selected close pairs at z > 1 with the intrinsic galaxy merger rate in the Illustris Simulations. To do so, we construct three 140 arcmin^2 lightcone catalogs and measure pair fractions, finding that they change little or decrease with increasing redshift at z > 1. Consistent with current surveys, this trend requires a decrease in the merger-pair observability time, roughly as (1 + z)^-2, in order to measure the merger rates of the same galaxies. This implies that major mergers are more common at high redshift than implied by the simplest arguments assuming a constant observability time. Several effects contribute to this trend: (1) The fraction of massive, major (4:1) pairs which merge by today increases weakly from ~0.5 at z=1 to ~0.8 at z=3. (2) The median time elapsed between an observed pair and final remnant decreases by a factor of two from z~1 to z~3. (3) An increasing specific star formation rate (sSFR) decreases the time during which common stellar-mass based pair selection criteria ...

  20. Host galaxies of double-peaked [OIII] emitting AGN: binary AGN or mergers?

    CERN Document Server

    Villforth, Carolin

    2013-01-01

    Mergers are suspected to be reliable triggers of both starformation and AGN activity. However, the exact timing of this process remains poorly understood. Here, we present deep imaging and long slit spectroscopy data of a sample of four double-peaked [OIII] emitting AGN. These sources are often believed to host binary AGN, or at least be currently undergoing major mergers. The sample presented here either have previous IFU and high resolution imaging data that show double-nuclei in the IR as well as kinematicly and spatially distinct line emitting regions. Two sources have detections of double point sources in either the X-ray or radio. The sources studied are therefore likely binary AGN. The AGN in this sample are luminous, radio-quiet and at low redshift. The $u/r/z$ imaging data show host galaxies in a wide range of merger stages, with the majority (3/4) showing tidal tails or complex kinematics and morphologies clearly indicating a recent merger. One source however -hosting a double X-ray source- shows qu...

  1. Merger and Centralisation : can We be Big AND Good

    Directory of Open Access Journals (Sweden)

    Bill Simpson

    2005-11-01

    Full Text Available The merger of the Victoria University of Manchester and UMIST in 2004 to create Britain’s largest university (though the achievement of world-class status rather than mere size was the real objective of the merger raised a range of parallel issues for the libraries of the two universities and for the Manchester Business School (MBS Library, which had previously operated independently, but was also merged into the new University Library. The first issue was the name of the new library and here the shift was so subtle that few people notice it until it is pointed out to them. If the “John Rylands University Library, The University of Manchester” seems hardly to differ from the “John Rylands University Library of Manchester” (the name of the former Victoria University of Manchester’s Library, this is because the Rylands name already has global brand recognition and it would have been foolish to risk a major name change that might have put that recognition at risk. It was a case of subtly shifting the emphasis of the name to reflect the fact that we are a new entity whilst not creating confusion in relation to our great historic collections.

  2. Magnetically-induced outflows from binary neutron star merger remnants

    CERN Document Server

    Siegel, Daniel M

    2015-01-01

    Recent observations by the Swift satellite have revealed long-lasting ($\\sim 10^2-10^5\\,\\mathrm{s}$), "plateau-like" X-ray afterglows in the vast majority of short gamma-ray bursts events. This has put forward the idea of a long-lived millisecond magnetar central engine being generated in a binary neutron star (BNS) merger and being responsible for the sustained energy injection over these timescales ("magnetar model"). We elaborate here on recent simulations that investigate the early evolution of such a merger remnant in general-relativistic magnetohydrodynamics. These simulations reveal very different conditions than those usually assumed for dipole spin-down emission in the magnetar model. In particular, the surrounding of the newly formed NS is polluted by baryons due to a dense, highly magnetized and isotropic wind from the stellar surface that is induced by magnetic field amplification in the interior of the star. The timescales and luminosities of this wind are compatible with early X-ray afterglows, ...

  3. Merger Signatures in the Galaxy Cluster Abell 98

    CERN Document Server

    Paterno-Mahler, Rachel; Bulbul, Esra; Andrade-Santos, Felipe; Blanton, Elizabeth L; Jones, Christine; Murray, Stephen; Johnson, Ryan E

    2014-01-01

    We present results from Chandra and XMM-Newton observations of Abell 98 (A98), a galaxy cluster with three major components: a relatively bright subcluster to the north (A98N), a disturbed subcluster to the south (A98S), and a fainter subcluster to the far south (A98SS). We find evidence for surface brightness and temperature asymmetries in A98N consistent with a shock-heated region to the south, which could be created by an early stage merger between A98N and A98S. Deeper observations are required to confirm this result. We also find that A98S has an asymmetric core temperature structure, likely due to a separate ongoing merger. Evidence for this is also seen in optical data. A98S hosts a wide-angle tail (WAT) radio source powered by a central active galactic nucleus (AGN). We find evidence for a cavity in the intracluster medium (ICM) that has been evacuated by one of the radio lobes, suggesting that AGN feedback is operating in this system. Examples of cavities in non-cool core clusters are relatively rare...

  4. Complex molecular gas structure in the Medusa merger

    CERN Document Server

    Aalto, S

    2000-01-01

    High resolution OVRO aperture synthesis maps of the 12CO 1-0 emission in the `Medusa' galaxy merger (NGC4194) reveal the molecular emission being surprisingly extended. It is distributed on a total scale of 25$''$ (4.7 kpc) - despite the apparent advanced stage of the merger. The complex, striking CO morphology occupies mainly the center and the north-eastern part of the main optical body. The extended 12CO flux is tracing two prominent dust lanes: one which is crossing the central region at right angle and a second which curves to the north-east and then into the beginning of the northern tidal tail. The bulk of the 12CO emission (67%) can be found in a complex starburst region encompassing the central 2kpc. The molecular gas is distributed in five major emission regions of typical size 300pc. About 15% of the total 12CO flux is found in a bright region 1.5'' south of the radio continuum nucleus. We suggest that this region together with the kpc sized central starburst is being fueled by gas flows along the ...

  5. Following Black Hole Scaling Relations Through Gas-Rich Mergers

    CERN Document Server

    Medling, Anne M; Max, Claire E; Sanders, David B; Armus, Lee; Holden, Bradford; Mieda, Etsuko; Wright, Shelley A; Larkin, James E

    2015-01-01

    We present black hole mass measurements from kinematic modeling of high-spatial resolution integral field spectroscopy of the inner regions of 9 nearby (ultra-)luminous infrared galaxies in a variety of merger stages. These observations were taken with OSIRIS and laser guide star adaptive optics on the Keck I and Keck II telescopes, and reveal gas and stellar kinematics inside the spheres of influence of these supermassive black holes. We find that this sample of black holes are overmassive ($\\sim10^{7-9}$ M$_{Sun}$) compared to the expected values based on black hole scaling relations, and suggest that the major epoch of black hole growth occurs in early stages of a merger, as opposed to during a final episode of quasar-mode feedback. The black hole masses presented are the dynamical masses enclosed in $\\sim$25pc, and could include gas which is gravitationally bound to the black hole but has not yet lost sufficient angular momentum to be accreted. If present, this gas could in principle eventually fuel AGN f...

  6. A survey of dual active galactic nuclei in simulations of galaxy mergers: frequency and properties

    Science.gov (United States)

    Capelo, Pedro R.; Dotti, Massimo; Volonteri, Marta; Mayer, Lucio; Bellovary, Jillian M.; Shen, Sijing

    2017-08-01

    We investigate the simultaneous triggering of active galactic nuclei (AGN) in merging galaxies, using a large suite of high-resolution hydrodynamical simulations. We compute dual-AGN observability time-scales using bolometric, X-ray and Eddington-ratio thresholds, confirming that dual activity from supermassive black holes (BHs) is generally higher at late pericentric passages, before a merger remnant has formed, especially at high luminosities. For typical minor and major mergers, dual activity lasts ˜20-70 and ˜100-160 Myr, respectively. We also explore the effects of X-ray obscuration from gas, finding that the dual-AGN time decreases at most by a factor of ˜2, and of contamination from star formation. Using projected separations and velocity differences rather than three-dimensional quantities can decrease the dual-AGN time-scales by up to ˜4, and we apply filters that mimic current observational-resolution limitations. In agreement with observations, we find that for a sample of major and minor mergers hosting at least one AGN, the fraction harbouring dual AGN is ˜20-30 and ˜1-10 per cent, respectively. We quantify the effects of merger mass ratio (0.1 to 1), geometry (coplanar, prograde and retrograde, and inclined), disc gas fraction and BH properties, finding that the mass ratio is the most important factor, with the difference between minor and major mergers varying between factors of a few to orders of magnitude, depending on the luminosity and filter used. We also find that a shallow imaging survey will require very high angular resolution whereas a deep imaging survey will be less resolution-dependent.

  7. Morphology and Molecular Gas Fractions of Local Luminous Infrared Galaxies as a Function of Infrared Luminosity and Merger Stage

    CERN Document Server

    Larson, Kirsten L; Barnes, Joshua E; Ishida, Cathy M; Evans, Aaron S; U, Vivian; Mazzarella, Joseph M; Kim, Don-Chan; Privon, George C; Mirabel, I Felix; Flewelling, Heather A

    2016-01-01

    We present a new, detailed analysis of the morphologies and molecular gas fractions for a complete sample of 65 local luminous infrared galaxies (LIRGs) from the Great Observatories All-Sky LIRG Survey (GOALS) using high resolution $I$-band images from The Hubble Space Telescope, the University of Hawaii 2.2m Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single undisturbed galaxies, minor mergers, and major mergers, with the latter divided into five distinct stages from pre-first pericenter passage to final nuclear coalescence. We find that major mergers of molecular gas-rich spirals clearly play a major role for all sources with $L_{\\rm IR} > 10^{11.5} L_\\odot $; however, below this luminosity threshold, minor mergers and secular processes dominate. Additionally, galaxies do not reach $L_{\\rm IR} > 10^{12.0} L_\\odot $ until late in the merger process when both disks are near final coalescence. The mean molecular gas fraction (MGF $= M_{\\rm H_2} / (M_* + M_{\\rm H_2})$) for non-inter...

  8. Merger mania: mergers and acquisitions in the generic drug sector from 1995 to 2016.

    Science.gov (United States)

    Gagnon, Marc-André; Volesky, Karena D

    2017-08-22

    Drug shortages and increasing generic drug prices are associated with low levels of competition. Mergers and acquisitions impact the level of competition. Record merger and acquisition activity was reported for the pharmaceutical sector in 2014/15, yet information on mergers and acquisitions in the generic drug sector are absent from the literature. This information is necessary to understand if and how such mergers and acquisitions can be a factor in drug shortages and increasing prices. Data on completed merger and acquisition deals that had a generic drug company being taken over (i.e. 'target') were extracted from Bloomberg Finance L.P. The number and announced value of deals are presented globally, for the United States, and globally excluding the United States annually from 1995 to 2016 in United States dollars. Generic drug companies comprised 9.3% of the value of all deals with pharmaceutical targets occurring from 1995 to 2016. Globally, in 1995 there were no deals, in 2014 there were 22 deals worth $1.86 billion, in 2015 there were 34 deals totalling $33.56 billion, and in 2016 there were 42 deals worth in excess of $44 billion. This substantial increase was partially attributed to Teva's 2016 acquisition of Allergan's generic drug business. The surge in mergers and acquisitions for 2015/16 was driven by deals in the United States, where they represented 89.7% of the dollar value of deals in those years. The recent blitz in mergers and acquisitions signals that the generic drug industry is undergoing a transformation, especially in the United States. This restructuring can negatively affect the level of competition that might impact prices and shortages for some products, emphasizing the importance of updating regulations and procurement policies.

  9. Synergic motives and economic success of mergers of Czech companies

    Directory of Open Access Journals (Sweden)

    Jaroslav Sedláček

    2013-01-01

    Full Text Available One of the motives for mergers and acquisitions is the synergy effect, which can take several forms. This paper tries to find out whether mergers implemented at the Czech market bring positive or negative synergies. The basis of our investigation is the database of the companies that implemented a merger within 2001–2009; out of these, the companies that published their financial statements in a digitalized form were selected. We monitored the development of six indicators characterizing the economic status of a company. The values of these indicators were compared for all participating companies before the merger and for the successor company three years after the merger. The hypotheses were formulated so that they expressed an expectation of a positive synergy brought about by mergers. However, hypothesis testing has not provided a clear result. A positive effect of a merger on the key indicator of net assets, whose growth means an increase in the accounting value of the company after the merger, has been proved for small and medium-sized companies only. The effect of mergers on the increase in indicators has been confirmed for retained earnings from past years and personal costs. Further research will concentrate on the relations between the indicators with the aim to create an integral indicator for the economic success of mergers.

  10. The typical mass ratio and typical final spin in supermassive black hole mergers

    CERN Document Server

    Gergely, László Á

    2012-01-01

    We prove that merging supermassive black holes (SMBHs) typically have neither equal masses, nor is their mass ratio too extreme. The majority of such mergers fall into the mass ratio range of 1:30 to 1:3, implying a spin flip during the inspiral. We also present a simple expression for the final spin $\\chi_{f}$ of the emerging SMBH, as function of the mass ratio, initial spin magnitudes, and orientation of the spins with respect to the orbital plane and each other. This formula approximates well more cumbersome expressions obtained from the fit with numerical simulations. By integrating over all equally likely orientations for precessing mergers we determine a lower approximant to the final spin distribution as function of the mass ratio alone. By folding this with the derived mass ratio dependent merger rate we derive a lower bound to the typical final spin value after mergers. We repeat the procedure deriving an upper bound for the typical spin in the case when the spins are aligned to the orbital angular m...

  11. Mergers of Unequal Mass Galaxies: Supermassive Black Hole Binary Evolution and Structure of Merger Remnants

    CERN Document Server

    Khan, Fazeel Mahmood; Berczik, Peter; Berentzen, Ingo; Just, Andreas; Spurzem, Rainer

    2012-01-01

    Galaxy centers are residing places for Super Massive Black Holes (SMBHs). Galaxy mergers bring SMBHs close together to form gravitationally bound binary systems which, if able to coalesce in less than a Hubble time, would be one of the most promising sources of gravitational waves for the Laser Interferometer Space Antenna (LISA). In spherical galaxy models, SMBH binaries stall at a separation of approximately one parsec, leading to the "final parsec problem" (FPP). On the other hand, it has been shown that merger-induced triaxiality of the remnant in equal-mass mergers is capable of supporting a constant supply of stars on so-called centrophilic orbits that interact with the binary and thus avoid the FPP. In this paper, using a set of direct N-body simulations of mergers of initially spherically symmetric galaxies with different mass ratios, we show that the merger-induced triaxiality is able to drive unequal-mass SMBH binaries to coalescence. The binary hardening rates are high and depend only weakly on the...

  12. Merger dan Akuisisi: Sebuah Perkawinan Paradoksal

    Directory of Open Access Journals (Sweden)

    Achmad Sobirin

    2009-08-01

    Full Text Available From human and cultural perspectives, it can be said that merger and aquisition (M&A is a kind of paradoxal marriage. While its main objective is to create synergy, the reality shows it differently. Many companies that decided to enter into M&A fail to achieve its objective particularly due to human and cultural problems. Therefore, to prevent, or at least, to minimize these problems, the companies should prepare psichologically, understand each others, and conduct due dilligent including human and cultural audit before entering into the marriage. This is what this paper is trying to discuss. By discussing this topic it is expected that human and cultural variables being neglected so far, are to be considered into the M&A’s decision so that the implementation of the marriage can be run smoothly.Keywords :  merger & acquisition ( M & A,  paradoxal marriage, open marriage, traditional marriage, modern marriage

  13. LISA parameter estimation using numerical merger waveforms

    Energy Technology Data Exchange (ETDEWEB)

    Thorpe, J I; McWilliams, S T; Kelly, B J; Fahey, R P; Arnaud, K; Baker, J G, E-mail: James.I.Thorpe@nasa.go [NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States)

    2009-05-07

    Recent advances in numerical relativity provide a detailed description of the waveforms of coalescing massive black hole binaries (MBHBs), expected to be the strongest detectable LISA sources. We present a preliminary study of LISA's sensitivity to MBHB parameters using a hybrid numerical/analytic waveform for equal-mass, non-spinning holes. The Synthetic LISA software package is used to simulate the instrument response, and the Fisher information matrix method is used to estimate errors in the parameters. Initial results indicate that inclusion of the merger signal can significantly improve the precision of some parameter estimates. For example, the median parameter errors for an ensemble of systems with total redshifted mass of 10{sup 6} M{sub o-dot} at a redshift of z approx 1 were found to decrease by a factor of slightly more than two for signals with merger as compared to signals truncated at the Schwarzchild ISCO.

  14. LISA parameter estimation using numerical merger waveforms

    CERN Document Server

    Thorpe, J I; Kelly, B J; Fahey, R P; Arnaud, K; Baker, J G

    2008-01-01

    Recent advances in numerical relativity provide a detailed description of the waveforms of coalescing massive black hole binaries (MBHBs), expected to be the strongest detectable LISA sources. We present a preliminary study of LISA's sensitivity to MBHB parameters using a hybrid numerical/analytic waveform for equal-mass, non-spinning holes. The Synthetic LISA software package is used to simulate the instrument response and the Fisher information matrix method is used to estimate errors in the parameters. Initial results indicate that inclusion of the merger signal can significantly improve the precision of some parameter estimates. For example, the median parameter errors for an ensemble of systems with total redshifted mass of one million Solar masses at a redshift of one were found to decrease by a factor of slightly more than two for signals with merger as compared to signals truncated at the Schwarzchild ISCO.

  15. Black hole mergers: beyond general relativity

    Science.gov (United States)

    Stein, Leo; Okounkova, Maria

    2017-01-01

    One hundred years after the birth of general relativity, advanced LIGO has finally directly detected gravitational waves. The source: two black holes merging into one. Advanced LIGO will soon provide the opportunity to test GR, using gravitational waves, in the dynamical strong-field regime-a setting where GR has not yet been tested. GR has passed all weak-field tests with flying colors. Yet it should eventually break down, so we must look to the strong-field. To perform strong-field tests of GR, we need waveform models from theories beyond GR. To date there are no numerical simulations of black hole mergers in theories which differ from GR. The main obstacle is the mathematical one of well-posedness. I will explain how to overcome this obstacle, and demonstrate the success of this approach by presenting the first numerical simulations of black hole mergers in a theory beyond GR.

  16. Mergers and acquisitions for the radiologist.

    Science.gov (United States)

    Fleishon, Howard B

    2008-05-01

    In 2006 and the first half of 2007, the rapid pace of global activity contributed to the popularity of mergers and acquisitions (M&A). In fact, the medical imaging industry has a significant history in M&A as well. Along with the expectation of continued growth in medical imaging utilization and other industry trends, radiologists may become more involved in M&A transactions. There is little in the radiology literature dealing with the logistics and pitfalls of M&A. This article is an introduction for radiologists who might consider buying or selling their practices or merging with strategic partners. Although there are significant differences in the approaches of buy or sell situations compared with mergers, they do share several concepts that are outlined. One key to success in M&A transactions is the "process" or approach, which is described with some practical guidelines. Some basic terms and suggestions are also presented for reference.

  17. Do Municipal Mergers Improve Fiscal Outcomes?

    DEFF Research Database (Denmark)

    Hansen, Sune Welling; Houlberg, Kurt; Holm Pedersen, Lene

    2014-01-01

    relationship between municipal mergers and fiscal outcomes is analysed. Measured on the balance between revenues and expenses, liquid assets and debts, municipal mergers improve the fiscal outcomes of the municipalities in a five-year perspective, although the pre-reform effects tend to be negative....... The basic argument is that the conceptualisation of fiscal management in political science is often too narrow as it focuses on the budget and pays hardly any attention to balances in the final accounts and debts – elements of management which are central to policy making. On this background, the causal...... of endogeneity problems and enabling causal inference. The analysis is based on administrative data from the Danish municipalities in the period 2003–11....

  18. Corporate reputation in mergers and acquisitions

    OpenAIRE

    Brandtzæg, Emilie

    2014-01-01

    The purpose of this master thesis is to uncover the role of corporate reputation as an intangible asset towards a sustainable competitive advantage in mergers and acquisitions. Identifying corporate reputation as an individual asset that generate future economic benefits, can provide as a basis of including corporate reputation in financial balance sheets and due diligence. If corporate reputation contributes with long-term financial and non-financial benefits, inquiring into corporate reputa...

  19. Estimating the potential gains from mergers

    DEFF Research Database (Denmark)

    Bogetoft, Peter; Wang, Dexiang

    2005-01-01

    We introduce simple production economic models to estimate the potential gains from mergers. We decompose the gains into technical ef¿ciency, size (scale) and harmony (mix) gains, and we discuss alternative ways to capture these gains. We propose to approximate the production processes using...... the non-parametric. Data Envelopment Analysis (DEA) approach, and we use the resulting operational approach to estimate the potential gains from merging agricultural extension of¿ces in Denmark....

  20. A Statoil Project : merger, agents and power

    OpenAIRE

    Buø, Julie Thue

    2012-01-01

    This master thesis investigates a case study of the experiences of eighteen Statoil project workers in terms of working in a large scale project as a unit in relation to other parts of the organization. Moreover, contextual conditions influence the experiences of the informants, such as the Statoil and Hydro merger of 2007. The informants are of both ex-Hydro and ex-Statoil background. The data is collected by qualitative interviews of each of the informants in collaboration with two othe...

  1. The rise and fall of stellar across the peak of cosmic star formation history: effects of mergers versus diffuse stellar mass acquisition

    Science.gov (United States)

    Welker, C.; Dubois, Y.; Devriendt, J.; Pichon, C.; Kaviraj, S.; Peirani, S.

    2017-02-01

    Building galaxy merger trees from a state-of-the-art cosmological hydrodynamics simulation, Horizon-AGN, we perform a statistical study of how mergers and smooth accretion drive galaxy morphologic properties above $z > 1$. More specifically, we investigate how stellar densities, effective radii and shape parameters derived from the inertia tensor depend on mergers of different mass ratios. We find strong evidence that smooth accretion tends to flatten small galaxies over cosmic time, leading to the formation of disks. On the other hand, mergers, and not only the major ones, exhibit a propensity to puff up and destroy stellar disks, confirming the origin of elliptical galaxies. We also find that elliptical galaxies are more susceptible to grow in size through mergers than disc galaxies with a size-mass evolution $r \\prop M^{1.2}$ instead of $r \\prop M^{-0.5} - M^{0.5}$ depending on the merger mass ratio. The gas content drive the size-mass evolution due to merger with a faster size growth for gas-poor galaxies $r \\prop M^2$ than for gas-rich galaxies $r \\prop M$.

  2. Experimentally, How Dark Are Black Hole Mergers?

    CERN Document Server

    Annis, James

    2016-01-01

    The first Advanced LIGO observing run detected two black hole merger events with confidence and likely a third. Many groups organized to followup the events in the optical even though the strong theoretical prior that no optical emission should be seen. We carry through the logic of this by asking about the experimental upper limits to the optical light from Advanced LIGO black hole mergere events. We inventory the published optical searches for transient events associated with the black hole mergers. We describe the factors that go into a formal limit on the visibility of an event (sky area coverage, the coverage factor of the camera, the fraction of sky not covered by intervening objects), and list what is known from the literature of the followup teams quantitative assessment of each factor. Where possible we calculate the total probability from each group that the source was imaged. The calculation of confidence level is reviewed for the case of no background. We find that an experimental 95% upper limit ...

  3. The Electromagnetic Signals of Compact Binary Mergers

    CERN Document Server

    Piran, T; Rosswog, S

    2012-01-01

    Compact binary mergers are prime sources of gravitational waves (GWs), targeted by current and next generation detectors. The question "what is the observable electromagnetic (EM) signature of a compact binary merger?" is an intriguing one with crucial consequences to the quest for gravitational waves. We present a large set of numerical simulations that focus on the electromagnetic signals that emerge from the dynamically ejected sub-relativistic material. These outflows produce on a time scale of a day macronovae - short-lived optical/UV signals powered by radioactive decay. In addition, the outflow interaction with the surrounding matter inevitably leads to a long-lasting radio emission. We calculate the expected radio signals from these outflows on time scales longer than a year, when the sub-relativistic ejecta dominate the emission. We discuss their detectability in 1.4 GHz and 150 MHz and compare it with an updated estimate of the detectability of short GRBs' orphan afterglows. We find that mergers wit...

  4. Sussing Merger Trees: Stability and Convergence

    CERN Document Server

    Wang, Yang; Knebe, Alexander; Schneider, Aurel; Srisawat, Chaichalit; Tweed, Dylan; Jung, Intae; Han, Jiaxin; Helly, John; Onions, Julian; Elahi, Pascal J; Thomas, Peter A; Behroozi, Peter; Yi, Sukyoung K; Rodriguez-Gomez, Vicente; Mao, Yao-Yuan; Jing, Yipeng; Lin, Weipeng

    2016-01-01

    Merger trees are routinely used to follow the growth and merging history of dark matter haloes and subhaloes in simulations of cosmic structure formation. Srisawat et al. (2013) compared a wide range of merger-tree-building codes. Here we test the influence of output strategies and mass resolution on tree-building. We find that, somewhat surprisingly, building the tree from more snapshots does not generally produce more complete trees; instead, it tends to short- en them. Significant improvements are seen for patching schemes which attempt to bridge over occasional dropouts in the underlying halo catalogues or schemes which combine the halo-finding and tree-building steps seamlessly. The adopted output strategy does not affec- t the average number of branches (bushiness) of the resultant merger trees. However, mass resolution has an influence on both main branch length and the bushiness. As the resolution increases, a halo with the same mass can be traced back further in time and will encounter more small pro...

  5. Thermonuclear detonations ensuing white dwarf mergers

    CERN Document Server

    Dan, Marius; Brüggen, Marcus; Ramirez-Ruiz, Enrico; Rosswog, Stephan

    2015-01-01

    The merger of two white dwarfs (WDs) has for many years not been considered as the favoured model for the progenitor system of type Ia supernovae (SNe Ia). But recent years have seen a change of opinion as a number of studies, both observational and theoretical, have concluded that they should contribute significantly to the observed type Ia supernova rate. In this paper, we study the ignition and propagation of detonation through post-merger remnants and we follow the resulting nucleosynthesis up to the point where a homologous expansion is reached. In our study we cover the entire range of WD masses and compositions. For the emergence of a detonation we study several setups, guided by both merger remnants from our own simulations and by results taken from the literature. We carefully compare the nucleosynthetic yields of successful explosions with SN Ia observations. Only three of our models are consistent with all the imposed constraints and potentially lead to a standard type Ia event. The first one, a $0...

  6. Mergers, Interactions, and The Fueling of Starbursts

    CERN Document Server

    Hibbard, J E

    1997-01-01

    The most active starbursts are found in galaxies with the highest IR luminosities, with peak star formation rates and efficiencies that are over an order of magnitude higher than in normal disk systems. These systems are almost exclusively on-going mergers. In this review I explore the conditions needed for interactions to experience such a phase by comparing two systems at similar stages of merging but quite different IR luminosities: NGC 4038/9 and Arp 299. These observations show that the most intense starbursts occur at the sites with the highest gas densities, which is a general result for IR luminous mergers. Observations and theory both suggest that the strength of the merger induced starburst depends on the internal structure of the progenitors, the amount and distribution of the gas, and the violence of the interaction. In particular, interactions involving progenitors with dense bulges, gas-rich disks, and/or a retrograde spin are expected to preferentially lead to large amounts of gaseous dissipati...

  7. CGCG 480-022: A distant lonesome merger?

    CERN Document Server

    Carretero, C; Gonzalez-Garcia, C; Beckman, J E; Quilis, V

    2006-01-01

    We present a complete analysis, which includes morphology, kinematics, stellar populations and N-body simulations of CGCG 480-022, the most distant (cz=14317 km/s) isolated galaxy studied so far in such detail. The results all support the hypothesis that this galaxy has suffered a major merger event with a companion of ~0.1 times its mass. Morphology reveals the presence of a circumnuclear ring and possibly further ring debris. The radial velocity curve looks symmetrical, whilst the velocity dispersion increases with radius reaching values that do not correspond to a virialized system. Moreover, this galaxy deviates significantly from the Fundamental Plane and the Faber-Jackson relation. The stellar population analysis show that the ring is younger and more metal-rich, which suggest that it has undergone a fairly recent burst of star formation. Both morphological and dynamical results are in broad agreeement with our N-body simulations.

  8. Merger Signatures in the Dynamics of Star-forming Gas

    CERN Document Server

    Hung, Chao-Ling; Smith, Howard A; Ashby, Matthew L N; Lanz, Lauranne; Martínez-Galarza, Juan R; Sanders, D B; Zezas, Andreas

    2015-01-01

    Spatially resolved kinematics have been used to determine the dynamical status of star-forming galaxies with ambiguous morphologies, and constrain the importance of galaxy interactions during the assembly of galaxies. However, measuring the importance of interactions or galaxy merger rates requires knowledge of the systematics in kinematic diagnostics and the visible time with merger indicators. We analyze the dynamics of star-forming gas in a set of binary merger hydrodynamic simulations with stellar mass ratios of 1:1 and 1:4. We find that the evolution of kinematic asymmetries traced by star-forming gas mirrors morphological asymmetries derived from mock optical images, in which both merger indicators show the largest deviation from isolated disks during strong interaction phases. Based on a series of simulations with various initial disk orientations, orbital parameters, gas fractions, and mass ratios, we find that the merger signatures are visible for ~0.2-0.4 Gyr with kinematic merger indicators but can...

  9. Merger Failures & Corporate Strategy: Change Management to Solve the Query

    Directory of Open Access Journals (Sweden)

    Hina Abbas

    2014-05-01

    Full Text Available Business Mergers are the key for both big and small business corporations. This research paper determines the factors resulting into merger failures and considering “Strategic Change Management” as a solution to the query by doing comparison of corporate strategy and cultures of mergers between Europe and USA through statistics. Factors that lead to merger failures are misgauging strategic fit, cultural clash, communication gap, weak leadership and economic crisis by providing clear vision, putting together leadership team, focused management on success and winning the people’s commitment we can solve this query. The research has proved that cross-border mergers are highly influenced by cultural differences. The strategic change management led by new CEO can help in saving a new merger from a failure.

  10. Binary Black Hole Mergers from Globular Clusters: Masses, Merger Rates, and the Impact of Stellar Evolution

    CERN Document Server

    Rodriguez, Carl L; Rasio, Frederic A

    2016-01-01

    Expanding upon our previous work (Rodriguez et al., 2015), we study merging binary black holes formed in globular clusters using our Monte Carlo approach to stellar dynamics. We have created a new set of 52 cluster models with different masses, metallicities, and radii to fully characterize the binary black hole merger rate. These models include all the relevant dynamical processes (such as two-body relaxation, strong encounters, and three-body binary formation) and agree well with detailed direct N-body simulations. In addition, we have enhanced our stellar evolution algorithms with updated metallicity-dependent stellar wind and supernova prescriptions, allowing us to compare our results directly to the most recent population synthesis predictions for merger rates from isolated binary evolution. We explore the relationship between a cluster's global properties and the population of binary black holes that it produces. In particular, we derive a numerically calibrated relationship between the merger times of ...

  11. Mergers, acquisitions and the evolution of construction professional services firm

    OpenAIRE

    Connaughton, John; Meikle, Jim; Teerikangas, Satu

    2015-01-01

    Whilst mergers and acquisitions are a favoured means of strategic renewal and expansion for firms, scant academic attention has been placed on the growth patterns of construction professional services firms (CPSFs). This paper focuses on the role of mergers and acquisitions in the evolution of CPSFs. The findings are based on an analysis of the growth patterns of the top 25 CPSFs in the United Kingdom between 1988 and 2013. Since the 1990s, the increase in merger and acquisition activity has ...

  12. Shell Galaxies: Dynamical Friction, Gradual Satellite Decay and Merger Dating

    CERN Document Server

    Ebrova, Ivana; Canalizo, Gabriela; Bennert, Nicola; Jilkova, Lucie

    2009-01-01

    With the goal to refine modelling of shell galaxies and the use of shells to probe the merger history, we develop a new method for implementing dynamical friction in test-particle simulations of radial minor mergers. The friction is combined with a gradual decay of the dwarf galaxy. The coupling of both effects can considerably redistribute positions and luminosities of shells; neglecting them can lead to significant errors in attempts to date the merger.

  13. Strategy and Tactics of International Mergers and Acquisitions

    Directory of Open Access Journals (Sweden)

    Denys Kiriakov

    2011-12-01

    Full Text Available The article reviews contemporary strategy and tactics issues in terms of international mergers and acquisitions, along with displaying cyclical waves of mergers and acquisitions over the last century as well as motivation thereof. Five strategies adhered to by international companies initiating conclusion of such agreements as well as challenges accompanying execution thereof have been analyzed. Modern strategic and tactical tools of international mergers and acquisitions process management have been researched on exemplary buyer (a corporation case-study.

  14. Boosted Tidal Disruption by Massive Black Hole Binaries During Galaxy Mergers from the View of N-Body Simulation

    Science.gov (United States)

    Li, Shuo; Liu, F. K.; Berczik, Peter; Spurzem, Rainer

    2017-01-01

    Supermassive black hole binaries (SMBHBs) are productions of the hierarchical galaxy formation model. There are many close connections between a central SMBH and its host galaxy because the former plays very important roles on galaxy formation and evolution. For this reason, the evolution of SMBHBs in merging galaxies is a fundamental challenge. Since there are many discussions about SMBHB evolution in a gas-rich environment, we focus on the quiescent galaxy, using tidal disruption (TD) as a diagnostic tool. Our study is based on a series of numerical, large particle number, direct N-body simulations for dry major mergers. According to the simulation results, the evolution can be divided into three phases. In phase I, the TD rate for two well separated SMBHs in a merging system is similar to that for a single SMBH in an isolated galaxy. After two SMBHs approach close enough to form a bound binary in phase II, the disruption rate can be enhanced by ∼2 orders of magnitude within a short time. This “boosted” disruption stage finishes after the SMBHB evolves to a compact binary system in phase III, corresponding to a reduction in disruption rate back to a level of a few times higher than in phase I. We also discuss how to correctly extrapolate our N-body simulation results to reality, and the implications of our results to observations.

  15. Using Black Hole Mergers to Explore Structure Formation

    Science.gov (United States)

    Alicea-Munoz, E.; Miller, M. Coleman

    2009-01-01

    Observations of gravitational waves from massive black hole mergers will open a new window into the era of structure formation in the early universe. Past efforts have concentrated on calculating merger rates using different physical assumptions, resulting in merger rate estimates that span a wide range (0.1 - 10(exp 4) mergers/year). We develop a semi-analytical, phenomenological model of massive black hole mergers that includes plausible combinations of several physical parameters, which we then turn around to determine how well observations with the Laser Interferometer Space Antenna (LISA) will be able to enhance our understanding of the universe during the critical z approximately equal to 5-30 epoch. Our approach involves generating synthetic LISA observable data (total BH masses, BH mass ratios, redshifts, merger rates), which are then analyzed using a Markov Chain Monte Carlo method, thus finding constraints for the physical parameters of the mergers. We find that our method works well at estimating merger parameters and that the number of merger events is a key discriminant among models, therefore making our method robust against observational uncertainties. Our approach can also be extended to more physically-driven models and more general problems in cosmology. This work is supported in part by the Cooperative Education Program at NASA/GSFC.

  16. Role of Human Resources in the Mergers and Acquisitions Processes

    Directory of Open Access Journals (Sweden)

    Anna Szewczyk

    2007-06-01

    Full Text Available The human resources are one of the most important topics when you talk about the value and importance of a company itself. The article tries to show the different aspects where the human resource affects a merger in the different states of a merger process, especially to the pre-merger-phase, and to which problems it can lead when you not pay attention to it. Finally the question, which is indeed the most important aim concerning mergers namely: how and in which degree the human resource effects the goodwill, is tried to answer.

  17. The incidence of stellar mergers and mass gainers among massive stars

    CERN Document Server

    de Mink, S E; Langer, N; Izzard, R G; Schneider, F R N

    2013-01-01

    Because the majority of massive stars are born as members of close binary systems, populations of massive main-sequence stars contain stellar mergers and products of binary mass transfer. We simulate populations of massive stars accounting for all major binary evolution effects based on the most recent binary parameter statistics and extensively evaluate the effect of model uncertainties. Assuming constant star formation, we find that $8^{+9}_{-4}\\,\\%$ of a sample of early type stars to be the product of a merger resulting from a close binary system. In total we find that $30^{+10}_{-15}\\,\\%$ of massive main-sequence stars are the product of binary interaction. We show that the commonly adapted approach to minimize the effects of binaries on an observed sample by excluding systems detected as binaries through radial velocity campaigns can be counterproductive. Systems with significant radial velocity variations are mostly pre-interaction systems. Excluding them substantially enhances the relative incidence of...

  18. Dry Etching

    DEFF Research Database (Denmark)

    Stamate, Eugen; Yeom, Geun Young

    2016-01-01

    Production of large-area flat panel displays (FPDs) involves several pattern transfer and device fabrication steps that can be performed with dry etching technologies. Even though the dry etching using capacitively coupled plasma is generally used to maintain high etch uniformity, due to the need...... for the higher processing rates in FPDs, high-density plasma processing tools that can handle larger-area substrate uniformly are more intensively studied especially for the dry etching of polysilicon thin films. In the case of FPD processing, the current substrate size ranges from 730 × 920 mm (fourth...... generation) to 2,200 × 2,500 mm (eighth generation), and the substrate size is expected to increase further within a few years. This chapter aims to present relevant details on dry etching including the phenomenology, materials to be etched with the different recipes, plasma sources fulfilling the dry...

  19. The case of BMW Group and Tesla Motors : mergers and acquisitions

    OpenAIRE

    Gomes, Luís Verdasca

    2013-01-01

    This case study provides analysis of a hypothetical M&A deal in the automotive industry. The main purpose is to consider if there is potential value creation when merging two different players, with different market approaches. The existing level of globalization that illustrates the majority of the markets has shaped the automotive industry into determined, multinational groups of companies. The rationale motivating this work lies in the fact that the merger of two different players in th...

  20. Simulations of binary galaxy mergers and the link with Fast Rotators, Slow Rotators, and Kinematically Distinct Cores

    CERN Document Server

    Bois, Maxime; Bournaud, Frédéric; Alatalo, Katherine; Blitz, Leo; Bureau, Martin; Cappellari, Michele; Davies, Roger L; Davis, Timothy A; de Zeeuw, P T; Duc, Pierre-Alain; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Lablanche, Pierre-Yves; McDermid, Richard M; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M

    2012-01-01

    We study the formation of early-type galaxies (ETGs) through mergers with a sample of 70 high-resolution numerical simulations of binary mergers of disc galaxies. These simulations encompass various mass ratios, initial conditions and orbital parameters. We find that binary mergers of disc galaxies with mass ratios of 3:1 and 6:1 are nearly always classified as Fast Rotators according to the Atlas3D criterion: they preserve the structure of the input fast rotating spiral progenitors. Major disc mergers (mass ratios of 2:1 and 1:1) lead to both Fast and Slow Rotators. Most of the Slow Rotators hold a stellar Kinematically Distinct Core (KDC) in their 1-3 central kilo-parsec: these KDCs are built from the stellar components of the progenitors. The mass ratio of the progenitors is a fundamental parameter for the formation of Slow Rotators in binary mergers, but it also requires a retrograde spin for the progenitor galaxies with respect to the orbital angular momentum. The importance of the initial spin of the pr...

  1. Failure of the merger of the Mount Sinai and New York University hospitals and medical schools: part 1.

    Science.gov (United States)

    Kastor, John A

    2010-12-01

    This is the first of two articles in this issue of Academic Medicine that, together, report the author's findings from his study of the attempts by the leaders of Mount Sinai and New York University (NYU) academic health centers in New York City to merge their medical schools and hospitals, and the failure of those attempts. The contemporary and predicted effects of managed care, capitation, and the Balanced Budget Act of 1997 were major factors stimulating this and other mergers at academic health centers. The hospital executives and board members also anticipated saving significant amounts of money by consolidating back-office functions and clinical services. The leadership at Mount Sinai were the most enthusiastic proponents of the merger. At NYU, many trustees feared that their hospital, which was generating a surplus when the merger was being planned, and its medical school, which operated at a deficit and was dependent on hospital earnings, would, in time, drain the university's endowment if the merger took place. Accordingly, some of the leading trustees favored separating its hospital and medical school from the university and consigning them to a new company with Mount Sinai. Influential members of the NYU faculty strongly opposed this. The attempt to create a merged entity of the hospitals and medical schools failed after several frustrating months of interinstitutional negotiations. The trustees and executives then attempted to develop a merger of only the hospitals; that process is described in the companion article in this issue of Academic Medicine.

  2. Merger Signatures in the Dynamics of Star-forming Gas

    Science.gov (United States)

    Hung, Chao-Ling; Hayward, Christopher C.; Smith, Howard A.; Ashby, Matthew L. N.; Lanz, Lauranne; Martínez-Galarza, Juan R.; Sanders, D. B.; Zezas, Andreas

    2016-01-01

    The recent advent of integral field spectrographs and millimeter interferometers has revealed the internal dynamics of many hundreds of star-forming galaxies. Spatially resolved kinematics have been used to determine the dynamical status of star-forming galaxies with ambiguous morphologies, and constrain the importance of galaxy interactions during the assembly of galaxies. However, measuring the importance of interactions or galaxy merger rates requires knowledge of the systematics in kinematic diagnostics and the visible time with merger indicators. We analyze the dynamics of star-forming gas in a set of binary merger hydrodynamic simulations with stellar mass ratios of 1:1 and 1:4. We find that the evolution of kinematic asymmetries traced by star-forming gas mirrors morphological asymmetries derived from mock optical images, in which both merger indicators show the largest deviation from isolated disks during strong interaction phases. Based on a series of simulations with various initial disk orientations, orbital parameters, gas fractions, and mass ratios, we find that the merger signatures are visible for ˜0.2-0.4 Gyr with kinematic merger indicators but can be approximately twice as long for equal-mass mergers of massive gas-rich disk galaxies designed to be analogs of z ˜ 2-3 submillimeter galaxies. Merger signatures are most apparent after the second passage and before the black holes coalescence, but in some cases they persist up to several hundred Myr after coalescence. About 20%-60% of the simulated galaxies are not identified as mergers during the strong interaction phase, implying that galaxies undergoing violent merging process do not necessarily exhibit highly asymmetric kinematics in their star-forming gas. The lack of identifiable merger signatures in this population can lead to an underestimation of merger abundances in star-forming galaxies, and including them in samples of star-forming disks may bias the measurements of disk properties such

  3. The VIMOS VLT Deep Survey: the contribution of minor mergers to the growth of L_B >= L*_B galaxies since z ~ 1 from spectroscopically identified pairs

    CERN Document Server

    López-Sanjuan, C; de Ravel, L; Cucciati, O; Ilbert, O; Tresse, L; Bardelli, S; Bolzonella, M; Contini, T; Garilli, B; Guzzo, L; Maccagni, D; McCraken, H J; Mellier, Y; Pollo, A; Vergani, D; Zucca, E

    2010-01-01

    In this work we measure the merger fraction, f_m, of L_B >= L*_B galaxies in the VVDS-Deep spectroscopic Survey. We define kinematical close pairs as those galaxies with a separation in the sky plane 5h^-1 kpc = 1/4 and 1/10 = mu) proportional to mu^s. The value of s evolves from s = -0.64 +- 0.13 at z = 0.8 to s = -1.11 +- 0.19 at z = 0.5. The fraction of minor mergers for bright galaxies decreases with redshift as a power-law (1+z)^m with index m = -0.4 +- 0.6 for the merger fraction and m = -0.8 +- 0.9 for the merger rate. We split our principal galaxies in red and blue by their rest-frame NUV-r colour, finding that i) f_m is higher for red galaxies, ii) f_m^red does not evolve with z, and iii) f_m^blue evolves dramatically. Our results show that the mass of normal L_B >= L*_B galaxies has grown ~25% since z ~ 1 because of minor and major mergers. The relative contribution of the mass growth by merging is ~25% due to minor mergers and ~75% due to major ones. The relative effect of merging is more important...

  4. Cross-border mergers and minority protection
    An open-ended harmonization

    Directory of Open Access Journals (Sweden)

    Marieke Wyckaert

    2008-03-01

    Full Text Available Minority protection is an important, though difficult, issue in company law, and a subtle balance must be struck between the legitimate interests of the majority and minority shareholder(s. The rules on minority protection in the context of the Cross-border Mergers Directive, which was recently adopted and should have been transposed into Member States’ national law towards the end of 2007, are examined in this paper. The authors analyse how minority shareholders are protected within the scope of this Directive and how some of the Member States (such as Germany, Italy, Belgium and the Netherlands have transposed or will transpose some of these protective provisions. The different levels of minority protection (information rights, consultation rights, rights to challenge majority decisions and other specific rights are considered, as well as which types of shareholders can benefit from such protection, and why they should be afforded protection. With respect to the last question, the authors conclude that the change in corporate law encountered especially by the shareholders of the disappearing company seems to be the major rationale underlying the European legislator's decision to introduce minority protection (but not oblige Member States to do so. The authors submit that this reflects too narrow a vision on the need for minority protection because it ignores the fact that the change of the corporate form as a consequence of a merger is in itself sufficient rationale for protecting minority shareholders. It remains somewhat of a mystery as to why the European legislator, while confirming that a cross-border merger should be subject to the same rules as a national merger, has created one possible and very vague exception to that rule.

  5. Cross-border mergers and minority protection An open-ended harmonization

    Directory of Open Access Journals (Sweden)

    Marieke Wyckaert

    2008-03-01

    Full Text Available Minority protection is an important, though difficult, issue in company law, and a subtle balance must be struck between the legitimate interests of the majority and minority shareholder(s. The rules on minority protection in the context of the Cross-border Mergers Directive, which was recently adopted and should have been transposed into Member States’ national law towards the end of 2007, are examined in this paper. The authors analyse how minority shareholders are protected within the scope of this Directive and how some of the Member States (such as Germany, Italy, Belgium and the Netherlands have transposed or will transpose some of these protective provisions. The different levels of minority protection (information rights, consultation rights, rights to challenge majority decisions and other specific rights are considered, as well as which types of shareholders can benefit from such protection, and why they should be afforded protection. With respect to the last question, the authors conclude that the change in corporate law encountered especially by the shareholders of the disappearing company seems to be the major rationale underlying the European legislator's decision to introduce minority protection (but not oblige Member States to do so. The authors submit that this reflects too narrow a vision on the need for minority protection because it ignores the fact that the change of the corporate form as a consequence of a merger is in itself sufficient rationale for protecting minority shareholders. It remains somewhat of a mystery as to why the European legislator, while confirming that a cross-border merger should be subject to the same rules as a national merger, has created one possible and very vague exception to that rule.

  6. The human resources in mergers and acquisitions

    Directory of Open Access Journals (Sweden)

    Noemí Martínez Caraballo

    2007-07-01

    Full Text Available In view of intangible resources -and, among them, human capital- play a significant role in the managerial strategy, this article aims to analyze the fit of human resources in companies that has been target of mergers and/or acquisitions processes. In this sense, the present paper will be centered in carrying out a state of the art of this topic and in showing some evidences about the top managers perceptions of the target company with the purpose of better understanding which are the reasons for the departure and the permanence of them.

  7. MORTUARY MERGERS AND THE INTERNATIONALIZATION OF INTERMENT

    Directory of Open Access Journals (Sweden)

    David O. Whitten

    2001-01-01

    Full Text Available “Mortuary Mergers and the Internationalization of Interment” is a study ofthe death services industry’s response to a changing market. Throughout the industry and across national borders, independent mortuaries and cemeteries are merging or consolidating. International death services firms are structured much as the automobile, oil, and communications multinationals are. Monopolistic competition is increasingly replaced by national and international oligopoly that may well translate into monopoly in isolated markets and lead to antitrust action and regulation. The study develops the historical roots of the death services industry but concentrates on the revolution underway. The prospects for the industry in the twenty-first century conclude the paper.

  8. Modelling Galaxy Merger Timescales and Tidal Destruction

    CERN Document Server

    Simha, Vimal

    2016-01-01

    We present a model for the dynamical evolution of subhaloes based on an approach combining numerical and analytical methods. Our method is based on tracking subhaloes in an N-body simulation up to the last point that it can be resolved, and applying an analytic prescription for its merger timescale that takes dynamical friction and tidal disruption into account. When applied to cosmological N-body simulations with mass resolutions that differ by two orders of magnitude, the technique produces halo occupation distributions that agree to within 3%.

  9. 12 CFR 931.5 - Liquidation, merger, or consolidation.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Liquidation, merger, or consolidation. 931.5 Section 931.5 Banks and Banking FEDERAL HOUSING FINANCE BOARD FEDERAL HOME LOAN BANK RISK MANAGEMENT AND CAPITAL STANDARDS FEDERAL HOME LOAN BANK CAPITAL STOCK § 931.5 Liquidation, merger, or consolidation....

  10. Remnant evolution after a carbon-oxygen white dwarf merger

    NARCIS (Netherlands)

    Yoon, S.C.; Podsiadlowski, P.; Rosswog, S.

    2007-01-01

    We systematically explore the evolution of the merger of two carbon-oxygen (CO) white dwarfs. The dynamical evolution of a 0.9Msolar + 0.6Msolar CO white dwarf merger is followed by a 3D smoothed particle hydrodynamics (SPH) simulation. The calculation uses a state-of-the-art equation of state that

  11. Migrating Legacy Systems in the Global Merger & Acquisition Environment

    Science.gov (United States)

    Katerattanakul, Pairin; Kam, Hwee-Joo; Lee, James J.; Hong, Soongoo

    2009-01-01

    The MetaFrame system migration project at WorldPharma, while driven by merger and acquisition, had faced complexities caused by both technical challenges and organizational issues in the climate of uncertainties. However, WorldPharma still insisted on instigating this post-merger system migration project. This project served to (1) consolidate the…

  12. Migrating Legacy Systems in the Global Merger & Acquisition Environment

    Science.gov (United States)

    Katerattanakul, Pairin; Kam, Hwee-Joo; Lee, James J.; Hong, Soongoo

    2009-01-01

    The MetaFrame system migration project at WorldPharma, while driven by merger and acquisition, had faced complexities caused by both technical challenges and organizational issues in the climate of uncertainties. However, WorldPharma still insisted on instigating this post-merger system migration project. This project served to (1) consolidate the…

  13. Value Creation through ICT Integration in Merger & Acquisition Processes

    DEFF Research Database (Denmark)

    Holm Larsen, Michael

    2005-01-01

    As deals are becoming more complex, and as technology, and the people supporting it, are becoming key drivers of merger and acquisition processes, planning of information and communication technologies in early stages of the integration process is vital to the realization of benefits of an Merger...

  14. Star formation in mergers with comologically motivated initial conditions

    NARCIS (Netherlands)

    Karman, Wouter; Macciò, Andrea V.; Kannan, Rahul; Moster, Benjamin P.; Somerville, Rachel S.

    2015-01-01

    We use semi-analytic models and cosmological merger trees to provide the initial conditions for multimerger numerical hydrodynamic simulations, and exploit these simulations to explore the effect of galaxy interaction and merging on star formation (SF). We compute numerical realizations of 12 merger

  15. Star formation in mergers with cosmologically motivated initial conditions

    NARCIS (Netherlands)

    Karman, Wouter; Macciò, Andrea V.; Kannan, Rahul; Moster, Benjamin P.; Somerville, Rachel S.

    2015-01-01

    We use semi-analytic models and cosmological merger trees to provide the initial conditions for multimerger numerical hydrodynamic simulations, and exploit these simulations to explore the effect of galaxy interaction and merging on star formation (SF). We compute numerical realizations of 12 merger

  16. Design study on the merger for BXERL-FEL

    Institute of Scientific and Technical Information of China (English)

    ZHU Xiong-Wei; WANG Shu-Hong; CHEN Sen-Yu

    2009-01-01

    In North China, there is a preliminary proposal for ERL-FEL light source (BXERL-FEL) with its aim at "one machine, two purposes" (the XFEL and ERL work simultaneously). One of the key technologies is the merger section. In this paper, we give the physical design of the merger section for BXERL-FEL which merges three kinds of electron beam.

  17. Strategic Mergers of Strong Institutions to Enhance Competitive Advantage

    Science.gov (United States)

    Harman, Grant; Harman, Kay

    2008-01-01

    Strategic mergers are formal combinations or amalgamations of higher education institutions with the aim of enhancing competitive advantage, or merging for "mutual growth". Recently, in a number of countries, there has been a decided shift from mergers initiated by governments, and dealing mainly with "problem" cases, towards…

  18. Hans A. Bethe Prize: Mergers of Binary Compact Objects

    Science.gov (United States)

    Kalogera, Vassiliki

    2016-03-01

    The inspiral and eventual merger of two compact objects in binary systems are important in astrophysics across the electromagnetic spectrum and as potential gravitational-wave sources. In this talk I will select a few topics of current interest to highlight compact-object mergers, including in the context of multi-messenger astrophysics.

  19. Strategic Mergers of Strong Institutions to Enhance Competitive Advantage

    Science.gov (United States)

    Harman, Grant; Harman, Kay

    2008-01-01

    Strategic mergers are formal combinations or amalgamations of higher education institutions with the aim of enhancing competitive advantage, or merging for "mutual growth". Recently, in a number of countries, there has been a decided shift from mergers initiated by governments, and dealing mainly with "problem" cases, towards…

  20. 29 CFR 4231.7 - De minimis mergers and transfers.

    Science.gov (United States)

    2010-07-01

    ... actuarial valuation. (b) De minimis merger defined. A merger is de minimis if the present value of accrued benefits (whether or not vested) of one plan is less than 3 percent of the fair market value of the other plan's assets. (c) De minimis transfer defined. A transfer of assets or liabilities is de minimis if...

  1. What Drives Private and Public Merger Waves in Europe?

    DEFF Research Database (Denmark)

    Bartholdy, Jan; Blunck, Benjamin

    What drives merger waves? Harford 2005 argues that mergers are an efficient response to economic shocks to an industry, whereas Rhodes-Kropf, Robinson & Viswanathan 2005 argues that merger waves are driven by overvaluation of the acquiring firm, and to a lesser extent, the target firm. Both paper...... significant differences between driving forces for listed firms and for private firms. Public or listed firm mergers and acquisitions are primarily driven by overvaluation or behavioural factors, whereas private transactions are driven by economic factors.......What drives merger waves? Harford 2005 argues that mergers are an efficient response to economic shocks to an industry, whereas Rhodes-Kropf, Robinson & Viswanathan 2005 argues that merger waves are driven by overvaluation of the acquiring firm, and to a lesser extent, the target firm. Both papers...... are based on empirical analyses of listed US firms. This paper presents additional evidence of merger waves in the European Union (EU). The use of European data allows a more detailed analysis, since firm level data is available for both listed as well as private transactions. This analysis reveals...

  2. Corporate Mergers in the Publishing Industry: Helpful or Intrusive?

    Science.gov (United States)

    Rudman, Herbert C.

    1990-01-01

    Examines the effects of corporate mergers in the publishing industry on the publishing of textbooks and standardized tests. Concludes that restructuring, acquisitions, and mergers have an intrusive effect on established practices of academic publishing and may severely limit the access of scholars to the academic marketplace. (FMW)

  3. Mergers and star formation in SPH cosmological simulations

    CERN Document Server

    Tissera, P B

    1999-01-01

    The star formation rate history of galactic objects in hydrodynamical cosmological simulations are analyzed in relation to their merger histories. The findings suggest that massive mergers produce more efficient starbursts and that, depending on the internal structure of the objects, double starbursts could also occur.

  4. Minor Mergers or Progenitor Bias? The Stellar Ages of Small and Large Quenched Galaxies

    Science.gov (United States)

    Fagioli, Martina; Carollo, C. Marcella; Renzini, Alvio; Lilly, Simon J.; Onodera, Masato; Tacchella, Sandro

    2016-11-01

    We investigate the origin of the evolution of the population-averaged size of quenched galaxies (QGs) through a spectroscopic analysis of their stellar ages. This evolution has been claimed to arise from either the size growth of individual galaxies through a sequence of dry minor mergers, or the addition of larger, newly quenched galaxies to the pre-existing population (i.e., a progenitor bias effect). We use the 20k zCOSMOS-bright spectroscopic survey to select bona fide QGs at 0.2 < z < 0.8. We stack their spectra in bins of redshift, stellar mass, and size to compute stellar population parameters through fits to the rest-frame optical spectra and Lick indices. The size-age relation differs below and above ˜1011 M ⊙: at 10.5\\lt {log} {M}* /{M}⊙ \\lt 11, at all redshifts the stellar populations of the largest galaxies are younger than those of the smaller counterparts, indicating progenitor bias as the main driver of the average size evolution. In contrast, at higher masses, there is no clear size-age trend, supporting a substantial role of dry mergers in increasing with cosmic time the sizes of these most massive QGs. The [α/Fe] abundance ratios of QGs are (i) above-solar over the entire redshift range of our analysis, hinting at universally short timescales for the buildup of the stellar populations of QGs, and (ii) similar at all masses and sizes, suggesting similar (short) timescales for the whole QG population—and strengthening the role of mergers in the buildup of the most massive QGs in the universe.

  5. EARNING MANAGEMENT, STOCK RETURN AND COMPANIES’ MERGER AND ACQUISITION

    Directory of Open Access Journals (Sweden)

    Sigit Handoyo

    2017-03-01

    Full Text Available The purpose of this study was to find out the practice earning management before merger and acquisitionannouncement. It also aimed to examine the differences of stock return before and after merger and acquisitionannouncement among companies that were listed on Indonesia stock exchange. The samples were 35 companiesthat did merger and acquisition and listed in Indonesia Stock Exchange (IDX period 2004–2013. Then, thedata analysis was performed by computer statistic program SPSS. These samples were selected by usingpurposive sampling method. Analysis hypothesis used Independent sample t-test and Wilcoxon sign rankstest. The result of independent sample t-test showed that the companies tended to do earning managementbefore merger and acquisitions. While the result of Wilcoxon signed ranks test showed that there was nodifference between stock return before and after merger and acquisition announcement.

  6. Electromagnetic Counterparts of Gravitational Wave Sources : Mergers of Compact Objects

    CERN Document Server

    Kamble, Atish

    2016-01-01

    Mergers of compact objects are considered prime sources of gravitational waves (GW) and will soon be targets of GW observatories such as the Advanced-LIGO, VIRGO etc. Finding electromagnetic counterparts of these GW sources will be important to understand their nature. We discuss possible electromagnetic signatures of the mergers. We show that the BH-BH mergers could have luminosities which exceed Eddington luminosity from unity to several orders of magnitude depending on the masses of the merging BHs. As a result these mergers could be explosive, release up to $10^{51}$ erg of energy and shine as radio transients. At any given time we expect about a few such transients in the sky at GHz frequencies which could be detected out to about 300 Mpc. It has also been argued that these radio transients would look alike radio supernovae with comparable detection rates. Multi-band follow up could, however, distinguish between the mergers and supernovae.

  7. The host galaxy and environment of a neutron star merger

    CERN Document Server

    Postigo, A de Ugarte; Rowlinson, A; Garcia-Benito, R; Levan, A J; Gorosabel, J; Goldoni, P; Schulze, S; Zafar, T; Wiersema, K; Sanchez-Ramirez, R; Melandri, A; D'Avanzo, P; Oates, S; D'Elia, V; De Pasquale, M; Kruehler, T; van der Horst, A J; Xu, D; Watson, D; Piranomonte, S; Vergani, S; Milvang-Jensen, B; Kaper, L; Malesani, D; Fynbo, J P U; Cano, Z; Covino, S; Flores, H; Greiss, S; Hammer, F; Hartoog, O E; Hellmich, S; Heuser, C; Hjorth, J; Jakobsson, P; Mottola, S; Sparre, M; Sollerman, J; Tagliaferri, G; Tanvir, N R; Vestergaard, M; Wijers, R A M J

    2013-01-01

    The mergers of neutron stars have been predicted to cause an r-process supernova - a luminous near-infrared transient powered by the radioactive decay of freshly formed heavy metals. An r-process supernova, or kilonova, has recently been discovered coincident with the short-duration gamma-ray burst GRB 130603B, simultaneously confirming the widely-held theory of the origin of most short-durations GRBs in neutron star mergers. We report here the absorption spectrum of the afterglow of this GRB. From it we determine the redshift of the burst and the properties of the host galaxy and the environment in which the merger occurred. The merger is not associated with the most star-forming region of the galaxy; however, it did occur in a dense region, implying a rapid merger or a low natal kick velocity for the neutron star binary.

  8. Impact of HMO mergers and acquisitions on financial performance.

    Science.gov (United States)

    Weech-Maldonado, Robert

    2002-01-01

    This study examines the effect of health maintenance organization (HMO) mergers and acquisitions on financial performance, as indicated by cash flow returns, profitability ratios, and efficiency indicators. Pooled, cross-sectional files of financial performance data were created for HMO mergers occurring in the period of 1988 to 1994. The study uses a time-series design involving the analysis of pre- and post-acquisition financial performance measured over a period of four years. Change scores for the industry-adjusted financial performance measures were calculated and then evaluated using t-tests. The study showed that HMO mergers had a positive effect on financial performance and efficiency. This effect disappeared, however, after adjusting for HMO industry returns. Potential synergies arising from HMO mergers have been largely illusory. Mergers may have been a result of non-value enhancing motives or management overconfidence.

  9. century drying

    Science.gov (United States)

    Cook, Benjamin I.; Smerdon, Jason E.; Seager, Richard; Coats, Sloan

    2014-11-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twenty-first century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman-Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  10. A survey of dual active galactic nuclei in simulations of galaxy mergers: frequency and properties

    CERN Document Server

    Capelo, Pedro R; Volonteri, Marta; Mayer, Lucio; Bellovary, Jillian M; Shen, Sijing

    2016-01-01

    We investigate the simultaneous triggering of active galactic nuclei (AGN) in merging galaxies, using a large suite of high-resolution hydrodynamical simulations. We compute dual-AGN observability time-scales using bolometric, X-ray, and Eddington-ratio thresholds, confirming that dual activity from supermassive black holes (BHs) is generally higher at late pericentric passages, before a merger remnant has formed, especially at high luminosities. For typical minor and major mergers, dual activity lasts ~20-70 and ~100-160 Myr, respectively. We also explore the effects of X-ray obscuration from gas, finding that the dual-AGN time decreases at most by a factor of ~2, and of contamination from star formation. Using projected separations and velocity differences rather than three-dimensional quantities can decrease the dual-AGN time-scales by up to ~4, and we apply filters which mimic current observational-resolution limitations. In agreement with observations, we find that, for a sample of major mergers hosting ...

  11. Black Hole Mergers as Probes of Structure Formation

    Science.gov (United States)

    Alicea-Munoz, E.; Miller, M. Coleman

    2008-01-01

    Intense structure formation and reionization occur at high redshift, yet there is currently little observational information about this very important epoch. Observations of gravitational waves from massive black hole (MBH) mergers can provide us with important clues about the formation of structures in the early universe. Past efforts have been limited to calculating merger rates using different models in which many assumptions are made about the specific values of physical parameters of the mergers, resulting in merger rate estimates that span a very wide range (0.1 - 104 mergers/year). Here we develop a semi-analytical, phenomenological model of MBH mergers that includes plausible combinations of several physical parameters, which we then turn around to determine how well observations with the Laser Interferometer Space Antenna (LISA) will be able to enhance our understanding of the universe during the critical z 5 - 30 structure formation era. We do this by generating synthetic LISA observable data (total BH mass, BH mass ratio, redshift, merger rates), which are then analyzed using a Markov Chain Monte Carlo method. This allows us to constrain the physical parameters of the mergers. We find that our methodology works well at estimating merger parameters, consistently giving results within 1- of the input parameter values. We also discover that the number of merger events is a key discriminant among models. This helps our method be robust against observational uncertainties. Our approach, which at this stage constitutes a proof of principle, can be readily extended to physical models and to more general problems in cosmology and gravitational wave astrophysics.

  12. The core-halo mass relation of ultra-light axion dark matter from merger history

    CERN Document Server

    Du, Xiaolong; Niemeyer, Jens C; Schwabe, Bodo

    2016-01-01

    In the context of structure formation with ultra-light axion dark matter, we offer an alternative explanation for the mass relation of solitonic cores and their host halos observed in numerical simulations. Our argument is based entirely on the mass gain that occurs during major mergers of binary cores and largely independent of the initial core-halo mass relation assigned to hosts that have just collapsed. We find a relation between the halo mass $M_h$ and corresponding core mass $M_c$, $M_c\\propto M_h^{2\\beta-1}$, where $(1-\\beta)$ is the core mass loss fraction. Following the evolution of core masses in stochastic merger trees, we find empirical evidence for our model. Our results are useful for statistically modeling the effects of dark matter cores on the properties of galaxies and their substructures in axion dark matter cosmologies.

  13. Galaxy Merger Morphologies and Time-Scales from Simulations of Equal-Mass Gas-Rich Disc Mergers

    CERN Document Server

    Lotz, Jennifer M; Cox, T J; Primack, Joel R

    2008-01-01

    A key obstacle to understanding the galaxy merger rate and its role in galaxy evolution is the difficulty in constraining the merger properties and time-scales from instantaneous snapshots of the real universe. The most common way to identify galaxy mergers is by morphology, yet current theoretical calculations of the time-scales for galaxy disturbances are quite crude. We present a morphological analysis of a large suite of GADGET N-Body/hydro-dynamical equal-mass gas-rich disc galaxy mergers which have been processed through the Monte-Carlo radiative transfer code SUNRISE. With the resulting images, we examine the dependence of quantitative morphology (G, M20, C, A) in the SDSS g-band on merger stage, dust, viewing angle, orbital parameters, gas properties, supernova feedback, and total mass. We find that mergers appear most disturbed in G-M20 and asymmetry at the first pass and at the final coalescence of their nuclei, but can have normal quantitative morphologies at other merger stages. The merger observa...

  14. Pair Fireball Precursors of Neutron Star Mergers

    CERN Document Server

    Metzger, Brian D

    2016-01-01

    If at least one neutron star (NS) is magnetized in a binary NS merger, then the orbital motion of the conducting companion through its dipole field during the final inspiral induces a strong voltage and current along the magnetic field lines connecting the two objects. If a modest fraction eta of the electromagnetic power extracted during the inspiral is used to accelerate relativistic particles, the resulting gamma-ray emission in such a compact volume will result in the formation of a thermal electron-positron pair fireball. Applying the steady-state pair wind model of Paczynski (1986), we quantify the luminosities and temperatures of the precursor fireball and its detectability with gamma-ray satellites. Under the assumption that eta ~ 1, the gamma-ray detection horizon of Dmax ~ 20(Bd/1e14 G) is much closer than the Advanced LIGO/Virgo horizon of 200 Mpc, unless the surface magnetic field of the NS is very strong, Bd > 1e15 G. Given the quasi-isotropic nature of the emission, a sub-population of mergers w...

  15. Life Extinctions due to Neutron Star Mergers

    CERN Document Server

    Dar, Arnon; Shaviv, N J; Dar, Arnon; Laor, Ari; Shaviv, Nir J.

    1996-01-01

    In a recent paper, Shaviv and Dar have shown that highly relativistic ejecta of high Z material from merger or accretion induced collapse of neutron stars can boost and beam star-light in dense stellar regions into cosmological gamma ray bursts (GRBs) whose predicted properties reproduce remarkably well the observed properties of GRBs. Generally, only a small fraction of the relativistic kinetic energy of the ejecta is converted into gamma rays and most of it is injected into the interstellar medium as a very powerful cosmic ray burst (CRB). Here we show that such CRBs can extinct life on Earth-like planets if they are closer than $\\sim 1 ~kpc$ from the merger/explosion. Such CRBs produce lethal fluxes of atmospheric muons at ground, underground and underwater. They also destroy the ozone layer, radioactivate the atmosphere and the surface of the planet and induce large climatic changes. They are enormously more violent than the GRBs alone or supernova explosions. In Milky-Way like galaxies they destroy life ...

  16. How Loud Are Neutron Star Mergers?

    CERN Document Server

    Bernuzzi, Sebastiano; Ott, Christian D; Roberts, Luke F; Moesta, Philipp; Galeazzi, Filippo

    2015-01-01

    We investigate neutron star merger dynamics using fully general relativistic simulations of equal and unequal-mass binaries sampling the galactic population, and including neutrino cooling and three different temperature-dependent microphysical equations of state. We focus on the emission of energy and angular momentum in gravitational waves in the postmerger phase. Our results reveal that the emitted gravitational-wave energy in the early evolution of the formed hypermassive neutron star (HMNS) is about twice as large as the energy emitted over the entire inspiral history of the binary. The total radiated energy per binary mass is comparable or larger than that of nonspinning black hole mergers. About $0.8-2.5\\%$ of the binary mass-energy is emitted at kHz frequencies in the early HMNS evolution due to the strong nonaxisymmetric deformation of the HMNS. Our results also show that the dimensionless spin of black holes resulting from subsequent HMNS collapse are limited to $\\lesssim0.7-0.8$. This may significa...

  17. Pair fireball precursors of neutron star mergers

    Science.gov (United States)

    Metzger, Brian D.; Zivancev, Charles

    2016-10-01

    If at least one neutron star (NS) is magnetized in a binary NS merger, then the orbital motion of the conducting companion during the final inspiral induces a strong voltage and current along the magnetic field lines connecting the NSs. If a modest fraction η of the extracted electromagnetic power extracted accelerates relativistic particles, the resulting gamma-ray emission a compact volume will result in the formation of an electron-positron pair fireball. Applying a steady-state pair wind model, we quantify the detectability of the precursor fireball with gamma-ray satellites. For η ˜ 1 the gamma-ray detection horizon of Dmax ≈ 10(Bd/1014 G)3/4 Mpc is much closer than the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo horizon of 200 Mpc, unless the NS surface magnetic field strength is very large, B_d ≲ 10^{15} G. Given the quasi-isotropic nature of the emission, mergers with weaker NS fields could contribute a nearby population of short gamma-ray bursts. Power not dissipated close to the binary is carried to infinity along the open field lines by a large-scale Poynting flux. Reconnection within this outflow, well outside of the pair photosphere, provides a potential site for non-thermal emission, such as a coherent millisecond radio burst.

  18. Mergers and obliquities in stellar triples

    Energy Technology Data Exchange (ETDEWEB)

    Naoz, Smadar [Harvard Smithsonian Center for Astrophysics, Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States); Fabrycky, Daniel C., E-mail: snaoz@cfa.harvard.edu [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)

    2014-10-01

    Many close stellar binaries are accompanied by a faraway star. The 'eccentric Kozai-Lidov' (EKL) mechanism can cause dramatic inclination and eccentricity fluctuations, resulting in tidal tightening of inner binaries of triple stars. We run a large set of Monte Carlo simulations, including the secular evolution of the orbits, general relativistic precession, and tides, and we determine the semimajor axis, eccentricity, inclination, and spin-orbit angle distributions of the final configurations. We find that the efficiency of forming tight binaries (≲ 16 days) when taking the EKL mechanism into account is ∼21%, and about 4% of all simulated systems ended up in a merger event. These merger events can lead to the formation of blue stragglers. Furthermore, we find that the spin-orbit angle distribution of the inner binaries carries a signature of the initial setup of the system; thus, observations can be used to disentangle close binaries' birth configuration. The resulting inner and outer final orbits' period distributions and their estimated fraction suggest that secular dynamics may be a significant channel for the formation of close binaries in triples and even blue stragglers.

  19. How loud are neutron star mergers?

    Science.gov (United States)

    Bernuzzi, Sebastiano; Radice, David; Ott, Christian D.; Roberts, Luke F.; Mösta, Philipp; Galeazzi, Filippo

    2016-07-01

    We present results from the first large parameter study of neutron star mergers using fully general relativistic simulations with finite-temperature microphysical equations of state and neutrino cooling. We consider equal and unequal-mass binaries drawn from the galactic population and simulate each binary with three different equations of state. Our focus is on the emission of energy and angular momentum in gravitational waves in the postmerger phase. We find that the emitted gravitational-wave energy in the first ˜10 ms of the life of the resulting hypermassive neutron star (HMNS) is about twice the energy emitted over the entire inspiral history of the binary. The total radiated energy per binary mass is comparable to or larger than that of nonspinning black hole inspiral-mergers. About 0.8-2.5% of the binary mass-energy is emitted at kHz frequencies in the early HMNS evolution. We find a clear dependence of the postmerger gravitational wave emission on binary configuration and equation of state and show that it can be encoded as a broad function of the binary tidal coupling constant κ2T. Our results also demonstrate that the dimensionless spin of black holes resulting from subsequent HMNS collapse are limited to ≲0.7 - 0.8 . This may significantly impact the neutrino pair annihilation mechanism for powering short gamma-ray bursts (sGRB).

  20. Dry cell battery poisoning

    Science.gov (United States)

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  1. A Multiwavelength Study of a Sample of 70 micron Selected Galaxies in the COSMOS Field II: The Role of Mergers in Galaxy Evolution

    CERN Document Server

    Kartaltepe, Jeyhan S; Le Floc'h, E; Frayer, D T; Aussel, H; Arnouts, S; Ilbert, O; Salvato, M; Scoville, N Z; Surace, J; Yan, L; Capak, P; Caputi, K; Carollo, C M; Cassata, P; Civano, F; Hasinger, G; Koekemoer, A M; Le Fèvre, O; Lilly, S; Liu, C T; McCracken, H J; Schinnerer, E; Smolcic, V; Taniguchi, Y; Thompson, D J; Trump, J; Baldassare, V F; Fiorenza, S L

    2010-01-01

    We analyze the morphological properties of a large sample of 1503 70 micron selected galaxies in the COSMOS field spanning the redshift range 0.011 being difficult to classify and subject to the effects of band pass shifting, therefore, these numbers can only be considered lower limits. At z1 the fraction of major mergers is at least 30-40% for ULIRGs. Although the general morphological trends agree with what has been observed for local (U)LIRGs, the fraction of major mergers is slightly lower than seen locally. This is in part due to the difficulty of identifying merger signatures at high redshift. W e argue that given the number of major gas-rich mergers observed and the relatively short timescale that they would be observable in the (U)LIRG phase that it is plausible for the observed red sequence of massive ellipticals (<10^12 M_sun) to have been formed entirely by gas-rich major mergers.

  2. NEUTRON-STAR MERGER EJECTA AS OBSTACLES TO NEUTRINO-POWERED JETS OF GAMMA-RAY BURSTS

    Energy Technology Data Exchange (ETDEWEB)

    Just, O.; Janka, H.-T.; Schwarz, N. [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85748 Garching (Germany); Obergaulinger, M. [Departament d´Astronomia i Astrofísica, Universitat de València, Edifici d´Investigació Jeroni Muñoz, C/ Dr. Moliner, 50, E-46100 Burjassot (València) (Spain); Bauswein, A., E-mail: ojust@mpa-garching.mpg.de, E-mail: thj@mpa-garching.mpg.de [Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

    2016-01-10

    We present the first special relativistic, axisymmetric hydrodynamic simulations of black hole-torus systems (approximating general relativistic gravity) as remnants of binary-neutron star (NS–NS) and neutron star–black hole (NS–BH) mergers, in which the viscously driven evolution of the accretion torus is followed with self-consistent energy-dependent neutrino transport and the interaction with the cloud of dynamical ejecta expelled during the NS–NS merging is taken into account. The modeled torus masses, BH masses and spins, and the ejecta masses, velocities, and spatial distributions are adopted from relativistic merger simulations. We find that energy deposition by neutrino annihilation can accelerate outflows with initially high Lorentz factors along polar low-density funnels, but only in mergers with extremely low baryon pollution in the polar regions. NS–BH mergers, where polar mass ejection during the merging phase is absent, provide sufficiently baryon-poor environments to enable neutrino-powered, ultrarelativistic jets with terminal Lorentz factors above 100 and considerable dynamical collimation, favoring short gamma-ray bursts (sGRBs), although their typical energies and durations might be too small to explain the majority of events. In the case of NS–NS mergers, however, neutrino emission of the accreting and viscously spreading torus is too short and too weak to yield enough energy for the outflows to break out from the surrounding ejecta shell as highly relativistic jets. We conclude that neutrino annihilation alone cannot power sGRBs from NS–NS mergers.

  3. EUROPEAN CROSS-BORDER MERGERS AND ACQUISITIONS- REALITIES AND PERSPECTIVES

    Directory of Open Access Journals (Sweden)

    Vancea Mariana

    2011-07-01

    Full Text Available This paper analyses the impact of the economic and financial crisis on merger and acquisition activity in Europe and the latest trends manifested on the cross-border merger and acquisition market involving European companies. Thus, a first objective of this research is to reveal the evolution of the European cross-border merger and acquisition activity in terms of dynamics, volume and structure. Another objective of this research is to reveal the short and medium term perspectives on mergers and acquisitions in Europe. Thus, under the continuous economic recovery of the European countries and the other worldwide economies, the recovery of financial markets and the growth of corporate profits, we shall witness an intensive cross-border merger and acquisition activity in Europe. The expansion engine of these operations seems to be represented by the emerging economies. This research is based on a systematic, logical and comparative analysis of scientific literature and statistical data regarding the cross-border mergers and acquisitions that involve European companies in recent years. This paper is part of the doctoral thesis Mergers and acquisitions- strategies of growth and development of enterprises. European and national particularities, coordinated by professor Ph.D. Alina Bădulescu from University of Oradea, Faculty of Economics. The doctoral research is supported by The Sectorial Operational Program for Human Resources Development 2007-2013, Contract POSDRU 59/1.5/S/1- Romanian researchers through modern and efficient doctoral programs.

  4. Dry Mouth

    Science.gov (United States)

    ... Use a fluoride rinse or brush-on fluoride gel before bedtime. See your dentist at least twice yearly to have your teeth examined and plaque removed, to help prevent tooth decay. Several herbal remedies have been used historically to treat dry ...

  5. Mergers and acquisitions: new arrangements in health care. Part 1.

    Science.gov (United States)

    Grant, E A

    1988-02-01

    Mergers and acquisitions are assuming a more important role in the healthcare industry today. These transactions require various issues be considered, such as valuation, capital planning, and so forth. In this article, the first in a five-part series on mergers and acquisitions, the fundamental methods and techniques of valuation are discussed. Some of these valuation methods, including comparative market transactions and free cash flow, are explained and examples are used to help potential purchasers and sellers to determine an organization's true value. Other articles in this series will include legal issues, tax implications, purchase investigations, and capital planning for mergers and acquisitions.

  6. Mergers and acquisitions in the international banking sector

    Directory of Open Access Journals (Sweden)

    Botis, S.

    2013-06-01

    Full Text Available The economic crisis emphasized the risks that banks assume and run. Reducing them is a strong reason for the acceleration of mergers and acquisitions in the international banking field. The merger of banking entities has established itself as a modern method of global credit risk management within every country and internationally. The main objective of this article is to highlight the latest developments on the bank mergers and acquisitions market in the U.S. and EU and on emerging market trends.

  7. Merger of binary neutron stars: Gravitational waves and electromagnetic counterparts

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Masaru

    2016-12-15

    Late inspiral and merger phases of binary neutron stars are the valuable new experimental fields for exploring nuclear physics because (i) gravitational waves from them will bring information for the neutron-star equation of state and (ii) the matter ejected after the onset of the merger could be the main site for the r-process nucleosynthesis. We will summarize these aspects of the binary neutron stars, describing the current understanding for the merger process of binary neutron stars that has been revealed by numerical-relativity simulations.

  8. Producing ultrastrong magnetic fields in neutron star mergers.

    Science.gov (United States)

    Price, D J; Rosswog, S

    2006-05-01

    We report an extremely rapid mechanism for magnetic field amplification during the merger of a binary neutron star system. This has implications for the production of the short class of gamma-ray bursts, which recent observations suggest may originate in such mergers. In detailed magnetohydrodynamic simulations of the merger process, the fields are amplified by Kelvin-Helmholtz instabilities beyond magnetar field strength and may therefore represent the strongest magnetic fields in the universe. The amplification occurs in the shear layer that forms between the neutron stars and on a time scale of only 1 millisecond, that is, long before the remnant can collapse into a black hole.

  9. How Enterprise Architecture Maturity Enables Post-merger IT Integration

    DEFF Research Database (Denmark)

    Törmer, Robert Lorenz; Henningsson, Stefan

    2017-01-01

    While world-wide Mergers and Acquisitions (M&As) activity continues to accelerate, a substantial proportion of deals fails to yield the expected value. The inability to plan and implement post-merger integration of information technology contributes substantially to these failure rates. This paper...... advances the argument that a company’s pre-existing Enterprise Architecture decisively shapes the capability to implement post-merger IT integration and subsequently realize benefits from M&A. Our multiple-case study investigates three acquisition cases and develops an explanatory theory of how Enterprise...

  10. An Empirical Analysis of Post-Merger Organizational Integration

    DEFF Research Database (Denmark)

    Smeets, Valerie Anne Rolande; Ierulli, Kathryn; Gibbs, Michael

    2016-01-01

    We study post-merger organizational integration using linked employer-employee data. Integration is implemented by reassigning a small number of high skilled workers, especially in R&D and management. Workforce mixing is concentrated to establishments set up after merger rather than to previously...... existing establishments. Worker turnover is high after merger, but new hiring yields stable total employment. Target employees have higher turnover and reassignment, particularly if the target firm is small relative to the acquiring firm. These findings may suggest integration is costly, but can...

  11. Electromagnetic Counterparts to Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.

    2011-01-01

    During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspirating BH system will interact strongly-on a purely Newtonian level-with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.

  12. Post-Merger Evolution of Betelgeuse

    Science.gov (United States)

    Sullivan, James; Wheeler, J. Craig; Nance, Sarafina; Diaz, Manuel

    2017-01-01

    Betelgeuse appears to rotate anomalously rapidly. One possible explanation is that if merged with a companion of about 1 solar mass when it evolved up the Hyashi track to become a red giant. We have used the MESA evolutionary code to explore the effects of such a merger. We have added a solar mass of matter with angular momentum corresponding to the Keplerian angular velocity at the current radius of Betelgeuse and then followed the evolution of that mass and angular momentum. A wave of angular momentum propagates in toward the core where it is stalled by the composition barrier at the boundary with the helium core. There is also a rearrangement of the envelope material that results in a decrease in the surface gravity, yielding a result in closer agreement with observations than either non-rotating models or models evolved from rotating ZAMS models.

  13. Fully compressive tides in galaxy mergers

    CERN Document Server

    Renaud, Florent; Naab, Thorsten; Theis, Christian

    2009-01-01

    The disruptive effect of galactic tides is a textbook example of gravitational dynamics. However, depending on the shape of the potential, tides can also become fully compressive. When that is the case, they might trigger or strengthen the formation of galactic substructures (star clusters, tidal dwarf galaxies), instead of destroying them. We perform N-body simulations of interacting galaxies to quantify this effect. We demonstrate that tidal compression occurs repeatedly during a galaxy merger, independently of the specific choice of parameterization. With a model tailored to the Antennae galaxies, we show that the distribution of compressive tides matches the locations and timescales of observed substructures. After extending our study to a broad range of parameters, we conclude that neither the importance of the compressive tides (~15% of the stellar mass) nor their duration (~ 10 Myr) are strongly affected by changes in the progenitors' configurations and orbits. Moreover, we show that individual clumps ...

  14. The Study of Airline Merger and Acquisition in the Great China Area

    Science.gov (United States)

    Shon, Zhengyi

    2003-01-01

    The Asian financial crisis in the late 20 th century has some long lasting effect on the air transportation industry in Asia, especially in the Great China Area. Starting from 1998, airlines in both China and Taiwan suffered some serious financial losses due to the diminishing travel demand caused by the economic recession. Airlines were forced to cut price to attract passengers and hence crashed the market discipline. A number of airline mergers and acquisitions were then driven by the markets and the governments. After China and Taiwan have both entered the World Trade Organization, some mega-merging cases were finalized in late 2002 for better fitting the world's aviation competitions. This paper reviews the nine merging and acquiring cases in the Great China Area in the past 5 years. Almost all the airlines in the area were involved. The new groups of airlines and the survival airlines are introduced. Market response to the airline mergers will also be examined. A general look over the performance of the new airlines will be discussed. And the future of the market will also be analyzed. Finally, the practices and the impacts of current inter-state mergers in the Great China Area will be examined. The study has expected a highly concentrated domestic market in both China and Taiwan. Each of the market will be dominated by three major airline groups of their own. Cross-holding equity within these 6 leading aviation groups would also be possible after further deregulations.

  15. Post-Mergers and Acquisitions: The Motives, Success Factors and Key Success Indicators

    Directory of Open Access Journals (Sweden)

    Hatem El Zuhairy

    2015-07-01

    Full Text Available There is a wide body of evidence showing a significant increase in the adoption of mergers and acquisitions (M&A worldwide. Moreover, research confirms that the integration and implementation stage (post-M&A has a major impact on the success or failure of a merger or acquisition. Therefore it has become increasingly important to explore the post-M&A phase further in order to support the management teams of organizations pursuing a merger or acquisition in meeting all their desired objectives. This paper proposes a framework to help in the successful execution of M&A. The framework contains three main elements: the motives, success factors and key success indicators (KSI. A qualitative research approach using the multiple case study methodology was conducted to test the framework. Ten case studies were selected from the industrial sector in Egypt and used to validate the research. The final version of the M&A framework was provided after applying the research results. Considering the practical implications of the M&A framework, a tool was proposed for its application in light of the balanced scorecard (BSC methodology. The proposed M&A scorecard tool should be used in the strategic planning and execution of M&A. Both the proposed M&A framework and the M&A scorecard tool should be used to guide the implementation of M&A in order to increase the success rate enjoyed by organizations.

  16. Modelling CO emission from hydrodynamic simulations of nearby spirals, starbursting mergers, and high-redshift galaxies

    CERN Document Server

    Bournaud, F; Weiss, A; Renaud, F; Mastropietro, C; Teyssier, R

    2014-01-01

    We model the intensity of emission lines from the CO molecule, based on hydrodynamic simulations of spirals, mergers, and high-redshift galaxies with very high resolutions (3pc and 10^3 Msun) and detailed models for the phase-space structure of the interstellar gas including shock heating, stellar feedback processes and galactic winds. The simulations are analyzed with a Large Velocity Gradient (LVG) model to compute the local emission in various molecular lines in each resolution element, radiation transfer and opacity effects, and the intensity emerging from galaxies, to generate synthetic spectra for various transitions of the CO molecule. This model reproduces the known properties of CO spectra and CO-to-H2 conversion factors in nearby spirals and starbursting major mergers. The high excitation of CO lines in mergers is dominated by an excess of high-density gas, and the high turbulent velocities and compression that create this dense gas excess result in broad linewidths and low CO intensity-to-H2 mass r...

  17. The Impact of Mergers and Acquisitions on Firm Performance: Evidence from the Pharmaceutical Industry

    OpenAIRE

    Kasetty, Soumya Ramesh

    2009-01-01

    The recent past has witnessed a significant increase in mergers and acquisition activity. Firms mainly engage in mergers to achieve corporate growth and realise their business strategy. Mergers and Acquisitions has been a popular strategy among companies, but however they may not always improve firm performance. Various theoretical and empirical studies have been conducted to measure the impact of mergers and acquisitions. Theoretically mergers and acquisitions have shown to improve company p...

  18. Neutrino flavor evolution in neutron star mergers

    Science.gov (United States)

    Tian, James Y.; Patwardhan, Amol V.; Fuller, George M.

    2017-08-01

    We examine the flavor evolution of neutrinos emitted from the disklike remnant (hereafter called "neutrino disk") of a binary neutron star (BNS) merger. We specifically follow the neutrinos emitted from the center of the disk, along the polar axis perpendicular to the equatorial plane. We carried out two-flavor simulations using a variety of different possible initial neutrino luminosities and energy spectra and, for comparison, three-flavor simulations in specific cases. In all simulations, the normal neutrino mass hierarchy was used. The flavor evolution was found to be highly dependent on the initial neutrino luminosities and energy spectra; in particular, we found two broad classes of results depending on the sign of the initial net electron neutrino lepton number (i.e., the number of neutrinos minus the number of antineutrinos). In the antineutrino-dominated case, we found that the matter-neutrino resonance effect dominates, consistent with previous results, whereas in the neutrino-dominated case, a bipolar spectral swap develops. The neutrino-dominated conditions required for this latter result have been realized, e.g., in a BNS merger simulation that employs the "DD2" equation of state for neutron star matter [Phys. Rev. D 93, 044019 (2016), 10.1103/PhysRevD.93.044019]. For this case, in addition to the swap at low energies, a collective Mikheyev-Smirnov-Wolfenstein mechanism generates a high-energy electron neutrino tail. The enhanced population of high-energy electron neutrinos in this scenario could have implications for the prospects of r -process nucleosynthesis in the material ejected outside the plane of the neutrino disk.

  19. Mass ejection in neutron star mergers

    Science.gov (United States)

    Rosswog, S.; Liebendörfer, M.; Thielemann, F.-K.; Davies, M. B.; Benz, W.; Piran, T.

    1999-01-01

    We present the results of 3D Newtonian SPH simulations of the merger of a neutron star binary. The microscopic properties of matter are described by the physical equation of state of Lattimer and Swesty (LS-EOS). To check the model dependence of the results we vary the resolution ( ~ 21000 and ~ 50000 particles), the equation of state (stiff and soft polytropes), the artificial viscosity scheme, the stellar masses, we include neutrinos (free-streaming limit), switch off the gravitational backreaction force, and vary the initial stellar spins. In addition we test the influence of the initial configuration, i.e. spherical stars versus corotating equilibrium configurations. The final matter distribution consists of a rapidly spinning central object with 2.5 to 3.1 Msun of baryonic mass that probably collapses to a black hole, a thick disk of 0.1 to 0.3 Msun and an extended low density region. In the case of corotation this low density material forms spiral arms that expand explosively due to an increase of the adiabatic exponent and the release of nuclear binding energy in the case of the LS-EOS, but remain narrow and well defined for the stiff polytropic equation of state. The main and new result is that for the realistic LS-EOS, depending on the initial spin, between 4*10(-3) and 4*10(-2) Msun of material become unbound. If, as suggested, large parts of this matter consist of r-process nuclei, neutron star mergers could account for the whole observed r-process material in the Galaxy.

  20. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: ... your eyes do not produce enough tears, it is called dry eye. Dry eye is also when ...

  1. LIGO Discovers the Merger of Two Black Holes

    Science.gov (United States)

    Kohler, Susanna

    2016-02-01

    Big news: the Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected its first gravitational-wave signal! Not only is the detection of this signal a major technical accomplishment and an exciting confirmation of general relativity, but it also has huge implications for black-hole astrophysics.What did LIGO see?LIGO is designed to detect the ripples in space-time created by two massive objects orbiting each other. These waves can reach observable amplitudes when a binary system consisting of two especially massive objects i.e., black holes or neutron stars reach the end of their inspiral and merge.LIGO has been unsuccessfully searching for gravitational waves since its initial operations in 2002, but a recent upgrade in its design has significantly increased its sensitivity and observational range. The first official observing run of Advanced LIGO began 18 September 2015, but the instruments were up and running in engineering mode several weeks before that. And it was in this time frame before official observing even began! that LIGO spotted its first gravitational wave signal: GW150914.One of LIGOs two detection sites, located near Hanford in eastern Washington. [LIGO]The signal, detected on 14 September, 2015, provides astronomers with a remarkable amount of information about the merger that caused it. From the detection, the LIGO team has extracted the masses of the two black holes that merged, 36+5-4 and 29+4-4 solar masses, as well as the mass of the final black hole formed by the merger, ~62 solar masses. The team also determined that the merger happened roughly a billion light-years away (at a redshift of z~0.1), and the direction of the signal was localized to an area of ~600 square degrees (roughly 1% of the sky).Why is this detection a big deal?This is the firstdirect detection of gravitational waves, providing spectacular further confirmation of Einsteins theory of general relativity. But the implications of GW150914 go far beyond this

  2. INCREASING THE ECONOMIC EFFICIENCY OF ENTERPRISES THROUGH MERGERS AND ACQUISITIONS

    National Research Council Canada - National Science Library

    SEHLEANU, Mariana

    2014-01-01

    In the literature there are many theories that try to explain why firms adopt the strategy of growth through mergers and acquisitions, or examine the particularities and consequences of this strategy...

  3. AN OVERVIEW ON THE DETERMINANTS OF MERGERS AND ACQUISITIONS WAVES

    Directory of Open Access Journals (Sweden)

    Vancea Mariana

    2012-12-01

    Full Text Available This paper concentrates on the presentation of the economic dimension of the mergers and acquisitions from a macroeconomic perspective. Thus, the objective of this paper is to reveal the main drivers of merger and acquisition activity. These operations take place in waves, which enters the context of changing the competition game marked by economic changes, technological evolutions, changes generated by the phenomenon of globalization, and by regulating changes. On the other side, a series of studies in the literature argue the existence of a connection between evaluating the securities and the merger and acquisition activity. This research is based on a systematic, logical and comparative analysis of scientific literature regarding the macroeconomic determinants of mergers and acquisitions.

  4. Numerical Relativity Simulations for Black Hole Merger Astrophysics

    Science.gov (United States)

    Baker, John G.

    2010-01-01

    Massive black hole mergers are perhaps the most energetic astronomical events, establishing their importance as gravitational wave sources for LISA, and also possibly leading to observable influences on their local environments. Advances in numerical relativity over the last five years have fueled the development of a rich physical understanding of general relativity's predictions for these events. Z will overview the understanding of these event emerging from numerical simulation studies. These simulations elucidate the pre-merger dynamics of the black hole binaries, the consequent gravitational waveform signatures ' and the resulting state, including its kick velocity, for the final black hole produced by the merger. Scenarios are now being considered for observing each of these aspects of the merger, involving both gravitational-wave and electromagnetic astronomy.

  5. Black Hole Mergers, Gravitational Waves, and Multi-Messenger Astronomy

    Science.gov (United States)

    Centrella, Joan M.

    2010-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. Although numerical codes designed to simulate black hole mergers were plagued for many years by a host of instabilities, recent breakthroughs have conquered these problems and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, astrophysics, and testing general relativity.

  6. Black-hole Merger Simulations for LISA Science

    Science.gov (United States)

    Kelly, Bernard J.; Baker, John G.; vanMeter, James R.; Boggs, William D.; Centrella, Joan M.; McWilliams, Sean T.

    2009-01-01

    The strongest expected sources of gravitational waves in the LISA band are the mergers of massive black holes. LISA may observe these systems to high redshift, z>10, to uncover details of the origin of massive black holes, and of the relationship between black holes and their host structures, and structure formation itself. These signals arise from the final stage in the development of a massive black-hole binary emitting strong gravitational radiation that accelerates the system's inspiral toward merger. The strongest part of the signal, at the point of merger, carries much information about the system and provides a probe of extreme gravitational physics. Theoretical predictions for these merger signals rely on supercomputer simulations to solve Einstein's equations. We discuss recent numerical results and their impact on LISA science expectations.

  7. Mergers involving academic health centers: a formidable challenge.

    Science.gov (United States)

    Pellegrini, V D

    2001-10-01

    Escalating economic pressures on the clinical enterprise threaten the missions of education and research in many of the most prestigious academic health centers. Following the model of industry, mergers of the healthcare delivery systems of teaching hospitals and clinics held promise for economies of scale and an improved operating margin. Failure to follow business principles in constructing the merged entity, differences in organizational governance and culture, and inability of physician leadership to prioritize, downsize, and consolidate clinical programs to optimize operational efficiencies all compromise the success of such mergers in academic medicine. Academic institutions and their respective governing boards need to exercise greater discipline in financial analysis and a willingness to make difficult decisions that show favor to one parent institution over another if mergers are to be effective in this setting. To date, an example of a vibrant and successful merger of academic health centers remains to be found.

  8. Black Hole Mergers and Gravitational Waves: Opening the New Frontier

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes produces a powerful burst of gravitational waves, emitting more energy than all the stars in the observable universe combined. Since these mergers take place in the regime of strong dynamical gravity, computing the gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For more than 30 years, scientists tried to simulate these mergers using the methods of numerical relativity. The resulting computer codes were plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. In the past several years, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will highlight these breakthroughs and the resulting 'gold rush' of new results that is revealing the dynamics of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  9. The delayed time distribution of massive double compact star mergers

    CERN Document Server

    Mennekens, N

    2016-01-01

    In order to investigate the temporal evolution of binary populations in general, double compact star binaries and mergers in particular within a galactic evolution context, a most straightforward method is obviously the implementation of a detailed binary evolutionary model in a galactic chemical evolution code. To our knowledge, only the Brussels galactic code explicitly accounts for binaries. With a galactic code that does not explicitly include binaries, the temporal evolution of the population of double compact star binaries and mergers can be estimated with reasonable accuracy if the delayed time distribution (DTD) for these mergers is available. The DTD for supernovae type Ia has been studied extensively the last decade. In the present paper we present the DTD for merging double neutron star binaries and mixed systems consisting of a neutron star and a black hole. The latter mergers are very promising sites for the production of r-process elements and the DTDs can be used to study the galactic evolution...

  10. Mergers and Acquisitions By China's Petroleum and Chemical Companies

    Institute of Scientific and Technical Information of China (English)

    Peter Zong

    2007-01-01

    @@ In the world of mergers and acquisitions (M&A), deals by Asian players usually account for around 15% of the activity.In 2005 and 2006, however, this proportion increased and was estimated to be 18% - 20%.

  11. Numerical Relativity Simulations for Black Hole Merger Astrophysics

    Science.gov (United States)

    Baker, John G.

    2010-01-01

    Massive black hole mergers are perhaps the most energetic astronomical events, establishing their importance as gravitational wave sources for LISA, and also possibly leading to observable influences on their local environments. Advances in numerical relativity over the last five years have fueled the development of a rich physical understanding of general relativity's predictions for these events. Z will overview the understanding of these event emerging from numerical simulation studies. These simulations elucidate the pre-merger dynamics of the black hole binaries, the consequent gravitational waveform signatures ' and the resulting state, including its kick velocity, for the final black hole produced by the merger. Scenarios are now being considered for observing each of these aspects of the merger, involving both gravitational-wave and electromagnetic astronomy.

  12. Should New Merger Guidelines Give UPP Market Definition?

    OpenAIRE

    Richard Schmalensee

    2009-01-01

    Even though in such cases most economists would place more weight on methods of assessing the competitive impact of mergers that do not rely on market definition, courts generally view market definition as an essential component of the case.

  13. Modeling the Effects of Mergers in the Retail Sector

    DEFF Research Database (Denmark)

    Blomgren-Hansen, Niels

    2013-01-01

    the retail and wholesale markets is constructed, calibrated and simulated based on a concrete case (the acquisition and merger of 250 shops previously organized in a voluntary chain of shops comprising roughly half of the market for high-end cosmetics in Denmark). Model simulations predicts that the merger......According to EU competition law, mergers that significantly impedes effective competition, particularly by creating or strengthening a dominant position are prohibited. To identify these cases, authorities need a quantifiable model of the relationship between the variables that are affected...... by the merger and some measure of competition. Furthermore, the authorities must make their decision quickly, rendering deliberate data collection and econometric analyses infeasible in practice. The decision must be based on easily accessible data. In this paper, a simple model of the interaction between...

  14. Mergers and acquisitions: some implications of cultural change.

    Science.gov (United States)

    Cavanaugh, S J

    1996-01-01

    A result of recent National Health Service reforms is the need to investigate, and possibly change, the culture of the professional working relationship between members of staff and their employer. This is particularly the case in situations of mergers and acquisitions where staff working from different cultural environments must work together. Mergers are becoming a feature of health service provision, perhaps this becomes most obvious with the recent moves by colleges of nursing and midwifery into the higher education sector and amalgamations of some purchasing authorities. Mergers highlight the practical issues of bringing together different organizational and work cultures to deliver a high quality service. This article discusses some aspects of the nature of organizational culture, the human impact of mergers and acquisitions and offers strategies for managing these events.

  15. Horizontal mergers and weak and strong competition commissions

    Directory of Open Access Journals (Sweden)

    Ristić Bojan

    2014-01-01

    Full Text Available In this paper we analyse the horizontal merger of companies in an already concentrated industry. The participants in mergers are obliged to submit notification to the Competition Commission but they also have the option of rejecting the merger. At the time of the notification submission the participants do not know whether the Commission is strong or weak, and they can complain to the Court if the Commission prohibits the merger. We model the strategic interaction between Participants and Commission in a dynamic game of incomplete information and determine weak perfect Bayesian equilibria. The main finding of our paper is that Participants will base their decision to submit notification on their belief in a weak Commission decision and will almost completely ignore the possibility of a strong Commission decision. We also provide a detailed examination of one case from Serbian regulatory practice, which coincides with the results of our game theoretical model.

  16. Modeling the Complete Gravitational Wave Spectrum of Neutron Star Mergers.

    Science.gov (United States)

    Bernuzzi, Sebastiano; Dietrich, Tim; Nagar, Alessandro

    2015-08-28

    In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency f2 related to the particular structure and dynamics of the remnant hot hypermassive neutron star. We show that f(2) is correlated with the tidal coupling constant κ(2)^T that characterizes the binary tidal interactions during the late-inspiral merger. The relation f(2)(κ(2)^T) depends very weakly on the binary total mass, mass ratio, equation of state, and thermal effects. This observation opens up the possibility of developing a model of the gravitational spectrum of every merger unifying the late-inspiral and postmerger descriptions.

  17. Factors Determining Mergers of Banks in Malaysia's Banking Sector Reform

    National Research Council Canada - National Science Library

    Rubi Ahmad; Mohamed Ariff; Michael Skully

    2007-01-01

    What was termed government-guided merger was a unique banking sector reform implemented in 2002 by the central bank of Malaysia guiding a larger number of depository institutions to form 10 large banks...

  18. CANDELS: CONSTRAINING THE AGN-MERGER CONNECTION WITH HOST MORPHOLOGIES AT z {approx} 2

    Energy Technology Data Exchange (ETDEWEB)

    Kocevski, Dale D.; Faber, S. M.; Mozena, Mark; Trump, Jonathan R.; Koo, David C. [University of California Observatories/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Koekemoer, Anton M.; Somerville, Rachel S.; Lotz, Jennifer M.; Dahlen, Tomas; Donley, Jennifer L. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Nandra, Kirpal; Brusa, Marcella; Wuyts, Stijn [Max-Planck-Institut fuer extraterrestrische Physik, D-85748 Garching (Germany); Rangel, Cyprian; Laird, Elise S. [Astrophysics Group, Imperial College London, London, SW7 2AZ (United Kingdom); Bell, Eric F. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Alexander, David M. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Bournaud, Frederic [CEA, IRFU, SAp and Laboratoire AIM Paris-Saclay, F-91191 Gif-sur-Yvette (France); Conselice, Christopher J. [Centre for Astronomy and Particle Theory, University of Nottingham, Nottingham, NG7 2RD (United Kingdom); Dekel, Avishai, E-mail: kocevski@ucolick.org [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); and others

    2012-01-10

    Using Hubble Space Telescope/WFC3 imaging taken as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, we examine the role that major galaxy mergers play in triggering active galactic nucleus (AGN) activity at z {approx} 2. Our sample consists of 72 moderate-luminosity (L{sub X} {approx} 10{sup 42-44} erg s{sup -1}) AGNs at 1.5 < z < 2.5 that are selected using the 4 Ms Chandra observations in the Chandra Deep Field South, the deepest X-ray observations to date. Employing visual classifications, we have analyzed the rest-frame optical morphologies of the AGN host galaxies and compared them to a mass-matched control sample of 216 non-active galaxies at the same redshift. We find that most of the AGNs reside in disk galaxies (51.4{sup +5.8}{sub -5.9}%), while a smaller percentage are found in spheroids (27.8{sup +5.8}{sub -4.6}%). Roughly 16.7{sup +5.3}{sub -3.5}% of the AGN hosts have highly disturbed morphologies and appear to be involved in a major merger or interaction, while most of the hosts (55.6{sup +5.6}{sub -5.9}%) appear relatively relaxed and undisturbed. These fractions are statistically consistent with the fraction of control galaxies that show similar morphological disturbances. These results suggest that the hosts of moderate-luminosity AGNs are no more likely to be involved in an ongoing merger or interaction relative to non-active galaxies of similar mass at z {approx} 2. The high disk fraction observed among the AGN hosts also appears to be at odds with predictions that merger-driven accretion should be the dominant AGN fueling mode at z {approx} 2, even at moderate X-ray luminosities. Although we cannot rule out that minor mergers are responsible for triggering these systems, the presence of a large population of relatively undisturbed disk-like hosts suggests that the stochastic accretion of gas plays a greater role in fueling AGN activity at z {approx} 2 than previously thought.

  19. Numerical Relativity, Black Hole Mergers, and Gravitational Waves: Part II

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    This series of 3 lectures will present recent developments in numerical relativity, and their applications to simulating black hole mergers and computing the resulting gravitational waveforms. In this second lecture, we focus on simulations of black hole binary mergers. We hig hlight the instabilities that plagued the codes for many years, the r ecent breakthroughs that led to the first accurate simulations, and the current state of the art.

  20. Value created or destroyed in mergers and acquisitions

    OpenAIRE

    Goel, Avnee

    2011-01-01

    In today’s global business environment, Mergers and Acquisitions (M&A) have become an important means of growth and survival for the companies. The key principle behind a merger or an acquisition is to create shareholders value since it is believed that two companies together are more valuable than two separate entities. Also these transactions help firms to expand internationally and pursue their other strategic and corporate goals. In this dissertation, we aim to study the rationales be...

  1. MERGER AND ACQUISITION - A STRATEGIC OPTION FOR COMPANIES

    OpenAIRE

    ANDREEA CEAUSESCU

    2008-01-01

    Business strategy is not a finished artefact, it is a work in progress. Even if its main purpose is profit, another one is growth. Growth, as a strategic choice, can be reached either by organic growth, by strategic alliances or by merger and acquisition (they are risky because of the incompatibility of different companies). In the paper below, we analyze merger and acquisition from the juridical and economic point of view, its international implication for companies in terms of advantages an...

  2. Managing Information Systems Integration in Corporate Mergers and Acquisitions

    OpenAIRE

    Henningsson, Stefan

    2008-01-01

    Corporate mergers and acquisitions (M&As) have during the last decade established themselves as prominent tools for corporate strategy. Consequently, more and more organizations direct their attention towards the potential benefits of a corporate merger and acquisition (M&A) and the problems of leveraging the potentials. This thesis addresses information systems (IS) integration in the context of M&As. It seeks to enhance the understanding of how IS integration relates to the M&am...

  3. Merger, Akusisi dan Konsolidasi dalam Perspektif Hukum Persaingan Usaha

    Directory of Open Access Journals (Sweden)

    Paulus Aluk Fadjar Dwi Santo

    2011-04-01

    Monopolistic Practices and Unfair Business Competition. Market impact of mergers, acquisitions and consolidation is important for analysis because it can have significant legal consequences for businesses, so that the research method used is the juridical normative and empirical approaches. In practice of mergers, acquisitions and consolidation intersect with regulation in other sectors, especially banking and capital markets. That is, there should be equality of perception and interpretation among the institutions that issued the policy.

  4. Transparency and Coordinated Effects in European Merger Control

    DEFF Research Database (Denmark)

    Albæk, Svend; Møllgaard, H. Peter; Overgaard, Per Baltzer

    2010-01-01

    In this paper, we first outline the foundations in economic theory of so-called coordinated effects with a particular view to mergers and with a special focus on transparency. Then, we review a number of seminal merger cases in EU competition policy (Airtours, Sony/BMG, ABF/GBI Business) in light...... widespread in the market in question. Finally, we briefly present a few other cases in which transparency has been an issue....

  5. A Reference Point Theory of Mergers and Acquisitions

    OpenAIRE

    Malcolm Baker; Xin Pan; Jeffrey Wurgler

    2009-01-01

    The use of judgmental anchors or reference points in valuing corporations affects several basic aspects of merger and acquisition activity including offer prices, deal success, market reaction, and merger waves. Offer prices are biased towards the 52-week high, a highly salient but largely irrelevant past price, and the modal offer price is exactly that reference price. An offer's probability of acceptance discontinuously increases when the offer exceeds the 52-week high; conversely, bidder s...

  6. Merger, Akusisi dan Konsolidasi dalam Perspektif Hukum Persaingan Usaha

    OpenAIRE

    Paulus Aluk Fajar Dwi Santo

    2011-01-01

    Mergers, acquisitions and consolidation is a business strategy that is commonly used in the business world to be able to build competitive advantage company, which in time can enhance shareholder value while maximizing the prosperity of the company owners or shareholders. To achieve the above objective normative, policy-makers need a plan and steps of strategic and accurate information to avoid the risk of failure. However, the strategy of merger, acquisition and consolidation of certain pote...

  7. Status and Future of Deep Searches for Compact Binary Mergers

    Science.gov (United States)

    Nitz, Alexander` Harvey; LIGO Scientific Collaboration

    2016-06-01

    Deep offline searches for gravitational waves from binary black hole, binary neutron star, and neutron star- black hole mergers were conducted during the first Advanced LIGO observing run, and recently Advanced LIGO announced the first detection of gravitational waves from a binary black hole merger. We discuss the recent results, the methodology of the high latency searches, along with improvements for the upcoming observing runs.

  8. GlaxoSmithKline: A merger too far?

    OpenAIRE

    Bernardo Batiz-Lazo

    2004-01-01

    This teaching case study summarises events leading to the creation of a global pharmaceutical giant and the early years of its performance while inviting readers to consider the process of growth through mergers and acquisitions as a general strategy. The case also looks at the expectations, deliberations and motivation of managers and stakeholders in doing so. The case invites readers to reflect on whether more mergers are to be the future of GlaxoSmithKline.

  9. "Vertical Market Power" as Oxymoron: Getting Convergence Mergers Right

    OpenAIRE

    Brennan, Timothy

    2001-01-01

    “Vertical market power” is a contradiction in terms because “market power” is essentially horizontal—that is, it depends on relationships of firms within markets. FERC invokes the term to assess “convergence” mergers between electricity generators and natural gas suppliers. It misapplies Department of Justice guidelines for vertical mergers and fails to identify exceptions to a presumption that market power depends only on competitive conditions at any single stage. A three-stage test can ass...

  10. Goal clarity and trust in management in educational mergers

    Directory of Open Access Journals (Sweden)

    T. May

    2007-12-01

    Full Text Available Purpose: The aim of this paper is to explore employees' opinions on goal clarity, trust in management and perceptions of organisational readiness for change in the context of the changes caused by the merger to form the Durban Institute of Technology (DIT in order to increase knowledge about the human aspects of mergers. Design/Methodology/Approach: A survey of staff was conducted, with a sample of respondents completing a questionnaire, which investigated whether or not there were relationships among the change variables, namely goal clarity, trust in management and perception of organisational readiness for change. Findings: The key finding of the study is that the goals of the institution were not clarified sufficiently during the change process at DIT. The correlation of goal clarity, trust in management and perceptions of organisational readiness for change were all significant at the p < 0.01 level; and the direction of the relationship between the variables was strongly positive (between 0.7 and 1.0. Implications: The results suggest that management success in identifying organisational goals clearly during a change initiative could help improve employees' attitudes, thereby increasing the likelihood of merger success, and minimising the negative reactions and staff dissatisfaction often associated with mergers. Originality/Value: Although there is a lot of research in the generic field of mergers and considerable research into mergers in higher education, both overseas and in South Africa, there is a lack of research in the human aspects of mergers. This is especially true of the three key change variables of perceptions of readiness for change, goal clarity and trust in management. Furthermore, what research there is has not focussed on the opinions of individual employees, but on the opinions of trade unions and student representatives. Therefore, this study contributes to filling an important gap in the literature on higher education

  11. The Luminosity Dependence of the Galaxy Merger Rate

    CERN Document Server

    Patton, D R

    2008-01-01

    We measure the number of companions per galaxy (Nc) as a function of r-band absolute magnitude for both the Sloan Digital Sky Survey and the Croton et al. (2006) semi-analytic catalog applied to the Millennium Run simulation. For close pairs with projected separations of 5-20 h^{-1} kpc, velocity differences less than 500 km/s, and luminosity ratios between 1:2 and 2:1, we find good agreement between the observations and simulations, with Nc consistently close to 0.02 over the range -22 < M_r < -18. For larger pair separations, Nc(M_r) instead becomes increasingly steep towards the faint end, implying that luminosity-dependent clustering plays an important role on small scales. Using the simulations to assess and correct for projection effects, we infer that the real-space Nc(M_r) for close pairs peaks at about M*, and declines by at least a factor of two as M_r becomes fainter. Conversely, by measuring the number density of close companions, we estimate that at least 90% of all major mergers occur betw...

  12. Galaxy Formation as a Cosmological Tool. I: The Galaxy Merger History as a Measure of Cosmological Parameters

    CERN Document Server

    Conselice, Christopher J; Mortlock, Alice; Palamara, David; Benson, Andrew J

    2014-01-01

    As galaxy formation and evolution over long cosmic time-scales depends to a large degree on the structure of the universe, the assembly history of galaxies is potentially a powerful approach for learning about the universe itself. In this paper we examine the merger history of dark matter halos based on the Extended Press-Schechter formalism as a function of cosmological parameters, redshift and halo mass. We calculate how major halo mergers are influenced by changes in the cosmological values of $\\Omega_{\\rm m}$, $\\Omega_{\\Lambda}$, $\\sigma_{8}$, the dark matter particle temperature (warm vs. cold dark matter), and the value of a constant and evolving equation of state parameter $w(z)$. We find that the merger fraction at a given halo mass varies by up to a factor of three for halos forming under the assumption of Cold Dark Matter, within different underling cosmological parameters. We find that the current measurements of the merger history, as measured through observed galaxy pairs as well as through struc...

  13. A critical look at the merger scenario to explain multiple populations and rotation in iron-complex globular clusters

    Science.gov (United States)

    Gavagnin, Elena; Mapelli, Michela; Lake, George

    2016-09-01

    Merging has been proposed to explain multiple populations in globular clusters (GCs) where there is a spread in iron abundance (hereafter, iron-complex GCs). By means of N-body simulations, we investigate if merging is consistent with the observations of subpopulations and rotation in iron-complex GCs. The key parameters are the initial mass and density ratios of the progenitors. When densities are similar, the more massive progenitor dominates the central part of the merger remnant and the less massive progenitor forms an extended rotating population. The low-mass progenitor can become the majority population in the central regions of the merger remnant only if its initial density is higher by roughly the mass ratio. To match the radial distribution of multiple populations in two iron-complex GCs (ω Cen and NGC 1851), the less massive progenitor needs to be four times as dense as the larger one. Our merger remnants show solid-body rotation in the inner parts, becoming differential in the outer parts. Rotation velocity V and ellipticity ɛ are in agreement with models for oblate rotators with isotropic dispersion. We discuss several kinematic signatures of a merger with a denser lower mass progenitor that can be tested with future observations.

  14. On the fragility of nuclear stellar discs against galaxy mergers: surviving photometric and kinematic signatures of nuclear discs

    CERN Document Server

    Sarzi, M; Dotti, M

    2015-01-01

    Nuclear stellar discs (NSDs) can help to constrain the assembly history of their host galaxies, as long as we can assume them to be fragile structures that are disrupted during merger events. In this work we investigate the fragility of NSDs by means of N-body simulations reproducing the last phases of a galaxy encounter, when the nuclear regions of the two galaxies merge. For this, we exposed a NSD set in the gravitational potential of the bulge and supermassive black hole of a primary galaxy to the impact of the supermassive black hole from a secondary galaxy. We explored merger events of different mass ratios, from major mergers with a 1:1 mass ratio to intermediate and minor interactions with 1:5 and 1:10 ratios, while considering various impact geometries. We analyse the end results of such mergers from different viewing angles and looked for possible photometric and kinematic signatures of the presence of a disc in the remnant surface density and velocity maps, while adopting detection limits from real ...

  15. Non-parametric Morphologies of Mergers in the Illustris Simulation

    CERN Document Server

    Bignone, Lucas A; Sillero, Emanuel; Pedrosa, Susana E; Pellizza, Leonardo J; Lambas, Diego G

    2016-01-01

    We study non-parametric morphologies of mergers events in a cosmological context, using the Illustris project. We produce mock g-band images comparable to observational surveys from the publicly available Illustris simulation idealized mock images at $z=0$. We then measure non parametric indicators: asymmetry, Gini, $M_{20}$, clumpiness and concentration for a set of galaxies with $M_* >10^{10}$ M$_\\odot$. We correlate these automatic statistics with the recent merger history of galaxies and with the presence of close companions. Our main contribution is to assess in a cosmological framework, the empirically derived non-parametric demarcation line and average time-scales used to determine the merger rate observationally. We found that 98 per cent of galaxies above the demarcation line have a close companion or have experienced a recent merger event. On average, merger signatures obtained from the $G-M_{20}$ criteria anticorrelate clearly with the elapsing time to the last merger event. We also find that the a...

  16. Searching for magnetar powered merger-novae from short GRBs

    CERN Document Server

    Gao, He; Lü, Hou-Jun; Li, Ye

    2016-01-01

    The merger of a double neutron star (NS-NS) binary may result in a rapidly rotating massive NS with an extremely strong magnetic field (i.e., a millisecond magnetar). In this case, the magnetic spin-down of the NS remnant provides an additional source of sustained energy injection, which would continuously power the merger ejecta. The thermal emission from the merger ejecta would give rise to a bright optical "magnetar-powered merger-nova". In this work, we carry out a complete search for magnetar-powered merger-nova from \\emph{Swift} short gamma-ray burst (SGRB) sample. We focus on short GRBs with extended emission or internal plateau, which may signify the presence of magnetars as the central engine. We eventually find three candidates of "magnetar-powered merger-nova" from the late observations of GRB 050724, GRB 070714B and GRB 061006. With standard parameter values, the magentar remnant scenario could well interpret the multi-band data of all three bursts, including the extended emission and their late c...

  17. Relationship between Pre and Post Merger and Acquisition Banking Industry Performance in Nigeria

    Directory of Open Access Journals (Sweden)

    Christian U. Amu

    2015-09-01

    Full Text Available The objective of this paper is to analyse the relationship between the pre and post merger and acquisition performance of banking industry in Nigeria. Aggregate banking data ranging from 1981 to 2013 were analysed for evidence of correlation between the pre-merger banking performance and post-merger banking performance in Nigeria. The results obtained from the descriptive analysis of the pre and post merger and acquisition periods shows that the banking industry performance is significantly better after the merger than before the merger. Furthermore, the Pearson correlation coefficients show that absence of relationship between the pre and post merger period. Overall, the results show that there is significant difference in the performance of Nigerian banking industry in the pre merger and post merger and acquisition periods.

  18. Detectability of compact binary merger macronovae

    CERN Document Server

    Rosswog, S; Korobkin, O; Wu, M -R; Sollerman, J; Goobar, A; Martinez-Pinedo, G

    2016-01-01

    We study the optical and near-infrared luminosities and detectability of radioactively powered electromagnetic transients ('macronovae') occuring in the aftermath of binary neutron star and neutron star black hole mergers. We explore the transients that result from the dynamic ejecta and those from different types of wind outflows. Based on full nuclear network simulations we calculate the resulting light curves in different wavelength bands. We scrutinize the robustness of the results by comparing a) two different nuclear reaction networks and b) two macronova models. We explore in particular how sensitive the results are to the production of alpha-decaying trans-lead nuclei. We compare two frequently used mass models: the Finite-Range Droplet Model (FRDM) and the nuclear mass model of Duflo and Zuker (DZ31). We find that the abundance of alpha-decaying trans-lead nuclei has a significant impact on the observability of the resulting macronovae. For example, the DZ31 model yields considerably larger abundance...

  19. Integrated delivery systems: mergers and acquisitions.

    Science.gov (United States)

    Pinkerton, S

    1999-01-01

    Mergers and acquisitions are usually the way an IDS is built. The CNO and/or CNOs/DONs have an integral role in the resolution of the M/A process. During this time of significant change, during which there may even be chaos, the CNOs work to maintain stability so there is as little impact as possible on patient outcomes, a core responsibility of the CNOs. The CNOs should focus on identifying and working with the highly skilled individuals in the organization to get to the recovery stage of the M/A process, at which time a high-performing organization is achieved. To build this new organization or IDS, the old organizations of the M/A must be changed (Moss Kanter, 1994). The successful CNOs will manage the trade-offs and will become experts in collaboration. The CNO's goals are to maximize the quality of patient care, the professional satisfaction of the nurse, and the goals of achieving cost effectiveness for the system (Clifford, 1998), and keeping this focus through the M/A process will yield success.

  20. A Strong Merger Shock in Abell 665

    Science.gov (United States)

    Dasadia, S.; Sun, M.; Sarazin, C.; Morandi, A.; Markevitch, M.; Wik, D.; Feretti, L.; Giovannini, G.; Govoni, F.; Vacca, V.

    2016-03-01

    Deep (103 ks) Chandra observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of M = 3.0 ± 0.6, propagating in front of a cold disrupted cloud. This makes Abell 665 the second cluster, after the Bullet cluster, where a strong merger shock of M ≈ 3 has been detected. The shock velocity from jump conditions is consistent with (2.7 ± 0.7) × 103 km s-1. The new data also reveal a prominent southern cold front with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the re-acceleration model with the X-ray and radio data combined.

  1. A Strong Merger Shock in Abell 665

    CERN Document Server

    Dasadia, Sarthak; Sarazin, Craig; Morandi, Andrea; Markevitch, Maxim; Wik, Daniel; Feretti, Luigina; Giovannini, Gabriele; Govoni, Federica; Vacca, Valentina

    2016-01-01

    Deep (103 ks) \\chandra\\ observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of $M$ = 3.0 $\\pm$ 0.6, propagating in front of a cold disrupted cloud. This makes Abell~665 the second cluster where a strong merger shock of $M \\approx$ 3 has been detected, after the Bullet cluster. The shock velocity from jump conditions is consistent with (2.7 $\\pm$ 0.7) $\\times$ 10$^3$ km sec$^{-1}$. The new data also reveal a prominent southern cold front, with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the re-acceleration model with the X-ray and radio data combined.

  2. The Galaxy Cluster Merger Catalog: An Online Repository of Mock Observations from Simulated Galaxy Cluster Mergers

    CERN Document Server

    ZuHone, J A

    2016-01-01

    We present the first release of the "Galaxy Cluster Merger Catalog". This catalog provides an extensive suite of mock observations and related data for N-body and hydrodynamical simulations of galaxy cluster mergers. These mock observations consist of projections of a number of important observable quantities in several different wavebands, for the entire evolution of each simulation as well as along different lines of sight through the three-dimensional simulation domain. The web interface to the catalog consists of easily browseable images over epoch and projection direction, as well as download links for the raw data and a JS9 interface for interactive data exploration. All of the data products are provided in the standard FITS file format, in image and table form. Data is being stored on the yt Hub (http://hub.yt), which allows for remote access and analysis using a Jupyter notebook server. Future versions of the catalog will include simulations from a number of research groups and a variety of research t...

  3. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd ... your vision. Privacy Policy Related New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

  4. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Written By: Kierstan Boyd Reviewed By: Brenda Pagan- ...

  5. What Is Dry Eye?

    Medline Plus

    Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué Es el Ojo Seco? ...

  6. Observing Mergers of Non-Spinning Black-Hole Binaries

    Science.gov (United States)

    McWilliams, Sean T.; Boggs, William D.; Baker, John G.; Kelly, Bernard J.

    2010-01-01

    Advances in the field of numerical relativity now make it possible to calculate the final, most powerful merger phase of binary black-hole coalescence for generic binaries. The state of the art has advanced well beyond the equal-mass case into the unequal-mass and spinning regions of parameter space. We present a study of the nonspinning portion of parameter space, primarily using an analytic waveform model tuned to available numerical data, with an emphasis on observational implications. We investigate the impact of varied m8BS ratio on merger signal-to-noise ratios (SNR) for several detectors, and compare our results with expectations from the test-mass limit. We note a striking similarity of the waveform phasing of the merger waveform across the available mass ratios. Motivated by this, we calculate the match between our equal-mass and 4:1 mass-ratio waveforms during the merger as a function of location on the source sky, using a new formalism for the match that accounts for higher harmonics. This is an indicator of the amount of degeneracy in mass ratio for mergers of moderate mass ratio systems.

  7. Magnetar Formation from the Merger of Binary Neutron Stars

    Science.gov (United States)

    Giacomazzo, Bruno

    2014-03-01

    I will discuss the results of recent fully general relativistic magnetohydrodynamic (GRMHD) simulations of binary neutron star (BNS) mergers performed with the Whisky code. I will describe in particular the role of magnetic fields in the post-merger dynamics, their impact on gravitational waves (GWs), and the possible formation of magnetars. The formation of a rapidly spinning magnetar after the merger could in particular generate electromagnetic signals that, if measured together with GWs emitted during the inspiral, could help to constrain the equation of state of NSs. Moreover BNSs are also thought to be behind the central engine of short gamma-ray bursts (SGRBs) and the formation of a magnetar could explain some of the observed SGRBs. While global GRMHD simulations of BNS mergers are currently unable to produce strong magnetic field amplifications during merger, local high-resolution simulations showed that small-scale turbulence can play a very important role in amplifying the magnetic fields. I will show how such small-scale dynamics can be included in global GRMHD BNS simulations via the implementation of a subgrid-scale model and its effect on the formation of magnetars.

  8. The Viscous Evolution of White Dwarf Merger Remnants

    CERN Document Server

    Schwab, Josiah; Quataert, Eliot; Dan, Marius; Rosswog, Stephan

    2012-01-01

    The merger of two white dwarfs (WDs) creates a differentially rotating remnant which is unstable to magnetohydrodynamic instabilities. These instabilities can lead to viscous evolution on a time-scale short compared to the thermal evolution of the remnant. We present multi-dimensional hydrodynamic simulations of the evolution of WD merger remnants under the action of an $\\alpha$-viscosity. We initialize our calculations using the output of eight WD merger simulations from Dan et al. (2011), which span a range of mass ratios and total masses. We generically find that the merger remnants evolve towards spherical states on time-scales of hours, even though a significant fraction of the mass is initially rotationally supported. The viscous evolution unbinds only a very small amount of mass $(< 10^{-5} M_\\odot)$. Viscous heating causes some of the systems we study with He WD secondaries to reach conditions of nearly dynamical burning. It is thus possible that the post-merger viscous phase triggers detonation of...

  9. Galaxy mergers with various mass ratios: properties of remnants

    CERN Document Server

    Bournaud, F; Combes, F

    2005-01-01

    We study galaxy mergers with various mass ratios using N-body simulations, with an emphasis on the unequal-mass mergers in the relatively unexplored range of mass-ratios 4:1-10:1. Our recent work (Bournaud et al. 2004) shows that the above range of mass ratio results in hybrid systems with spiral-like luminosity profiles but with elliptical-like kinematics, as observed in the data analysis for a sample of mergers by Jog & Chitre (2002). In this paper, we study the merger-remnants for mass ratios from 1:1 to 10:1 while systematically covering the parameter space. We obtain the morphological and kinematical properties of the remnants, and also discuss the robustness and the visibility of disks in the merger remnants with a random line-of-sight. We show that the mass ratios 1:1-3:1 give rise to elliptical remnants whereas the mass ratios 4.5:1-10:1 produce the hybrid systems with mixed properties. We find that the transition between disk-like and elliptical remnants occurs between a narrow mass-range of 4.5:...

  10. CREATING OR DESTROYING VALUE THROUGH MERGERS AND ACQUISITIONS?

    Directory of Open Access Journals (Sweden)

    Sehleanu Mariana

    2015-07-01

    Full Text Available The avalanche of operations performed and their specificities revealed several motivations for mergers and acquisitions However, although they are concluded with the purpose of value creation, reality has shown that in many cases it was exactly the opposite, these transactions led to value destruction. The paper aims to analyze the operations of mergers and acquisitions starting from the value theories, emphasizing their motivations and consequences regarding value creation. This is a theoretical research and we have used as a research method the qualitative approach in order to identify the motivations and the generating factors of mergers and acquisitions. Mergers and acquisitions can contribute to the creation of value, the main motivation being represented by the improvement of the economic performance of the new entity formed, by achievement of synergies, by increasing market power or by replacing inefficient management teams. However, the reality showed that these operations haven’t always a beneficial role for the “health” of a company that wishes to adopt an external growth strategy. Analyzing from an opposite perspective, we emphasized the motivations underlying value destruction by mergers and acquisitions. The existence of conflicts of interest between managers and shareholders, of a free cash flow, the managers’ desire to strengthen their position in the company to built an “empire” or even the pride and overconfidence of the managers regarding their abilities to create value are other reasons that underlie the occurrence of these operations.

  11. The Impact Of Adjustment In Capital Structure In Mergers & Acquisitions On Us Acquirers' Business Performance

    National Research Council Canada - National Science Library

    Taoufik Bouraoui; Ting Li

    2014-01-01

    ...) and Return On Assets (ROA) to measure post-merger performance. We find that leverage changes have a negative impact on performance, in both the short and long run after Mergers & Acquisitions (M&A...

  12. University Merger Reforms: Rational, political, institutional or incidental processes? The case of Denmark

    DEFF Research Database (Denmark)

    Aagaard, Kurt; Hansen, Hanne Foss; Rasmussen, Jørgen Gulddahl

    Mergers have for some years been popular within the public sector in many countries this includes mergers between higher education institutions. In the Danish university and Government Research Institutions sector a process of merger took place in 2006. ‘University merger reforms’ is an analysis ...... on an organizational level demands the use of more than one conceptual model for agenda-setting - decision making and institutional restructuring,......-sector and some of the conclusions made from other kinds of merger studies. Important conclusions of the study of the three universities are that mergers and especially post-mergers processes are much more than linear, straight forward rational processes and that understanding merger processes...

  13. A New Automatic Method to Identify Galaxy Mergers I. Description and Application to the STAGES Survey

    CERN Document Server

    Hoyos, Carlos; Gray, Meghan E; Maltby, David T; Bell, Eric F; Barazza, Fabio D; Boehm, Asmus; Haussler, Boris; Jahnke, Knud; Jogee, Sharda; Lane, Kyle P; McIntosh, Daniel H; Wolf, Christian

    2011-01-01

    We present an automatic method to identify galaxy mergers using the morphological information contained in the residual images of galaxies after the subtraction of a Sersic model. The removal of the bulk signal from the host galaxy light is done with the aim of detecting the fainter minor mergers. The specific morphological parameters that are used in the merger diagnostic suggested here are the Residual Flux Fraction and the asymmetry of the residuals. The new diagnostic has been calibrated and optimized so that the resulting merger sample is very complete. However, the contamination by non-mergers is also high. If the same optimization method is adopted for combinations of other structural parameters such as the CAS system, the merger indicator we introduce yields merger samples of equal or higher statistical quality than the samples obtained through the use of other structural parameters. We explore the ability of the method presented here to select minor mergers by identifying a sample of visually classif...

  14. Dry Skin

    Science.gov (United States)

    ... often is overlooked as a major feature of Sjögren’s syndrome but deserves greater recognition as a frequent issue ... immediately use a moisturizer. For more information on Sjögren’s syndrome, visit the SSF Web site at www.sjogrens. ...

  15. Relationship between Pre and Post Merger and Acquisition Banking Industry Performance in Nigeria

    OpenAIRE

    Christian U. Amu; Ezeji Emmanuel Chigbu

    2015-01-01

    The objective of this paper is to analyse the relationship between the pre and post merger and acquisition performance of banking industry in Nigeria. Aggregate banking data ranging from 1981 to 2013 were analysed for evidence of correlation between the pre-merger banking performance and post-merger banking performance in Nigeria. The results obtained from the descriptive analysis of the pre and post merger and acquisition periods shows that the banking industry performance is significantly b...

  16. The Effect of the Big Eight Accounting Firm Mergers on the Market for Audit Services.

    OpenAIRE

    Sullivan, Mary W

    2002-01-01

    The research assesses whether the two Big Eight mergers of 1989 were anticompetitive or efficiency enhancing. The study determines how a merger would affect the merged firm's probability of winning an auction to supply audit services under four different merger theories. A data set of 1,978 firms over a 12-year period is constructed to test these theories. The main conclusion of the analysis is that the Big Eight mergers of 1989 resulted in cost reductions that benefited relatively large audi...

  17. Astrophysics of Super-Massive Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.

    2013-01-01

    We present here an overview of recent work in the subject of astrophysical manifestations of super-massive black hole (SMBH) mergers. This is a field that has been traditionally driven by theoretical work, but in recent years has also generated a great deal of interest and excitement in the observational astronomy community. In particular, the electromagnetic (EM) counterparts to SMBH mergers provide the means to detect and characterize these highly energetic events at cosmological distances, even in the absence of a space-based gravitational-wave observatory. In addition to providing a mechanism for observing SMBH mergers, EM counterparts also give important information about the environments in which these remarkable events take place, thus teaching us about the mechanisms through which galaxies form and evolve symbiotically with their central black holes.

  18. Neutrino Flavor Evolution in Binary Neutron Star Merger Remnants

    CERN Document Server

    Frensel, Maik; Volpe, Cristina; Perego, Albino

    2016-01-01

    We study the neutrino flavor evolution in the neutrino-driven wind from a binary neutron star merger remnant consisting of a massive neutron star surrounded by an accretion disk. With the neutrino emission characteristics and the hydrodynamical profile of the remnant consistently extracted from a three-dimensional simulation, we compute the flavor evolution by taking into account neutrino coherent forward scattering off ordinary matter and neutrinos themselves. We employ a "single-trajectory" approach to investigate the dependence of the flavor evolution on the neutrino emission location and angle. We also show that the flavor conversion in the merger remnant can affect the (anti-)neutrino absorption rates on free nucleons and may thus impact the $r$-process nucleosynthesis in the wind. We discuss the sensitivity of such results on the change of neutrino emission characteristics, also from different neutron star merger simulations.

  19. Exact Event Horizon of a Black Hole Merger

    CERN Document Server

    Emparan, Roberto

    2016-01-01

    We argue that the event horizon of a binary black hole merger, in the extreme-mass-ratio limit where one of the black holes is much smaller than the other, can be described in an exact analytic way. This is done by tracing in the Schwarzschild geometry a congruence of null geodesics that approaches a null plane at infinity. Its form can be given explicitly in terms of elliptic functions, and we use it to analyze and illustrate the time-evolution of the horizon along the merger. We identify features such as the line of caustics at which light rays enter the horizon, and the critical point at which the horizons touch. We also compute several quantities that characterize these aspects of the merger.

  20. Exact event horizon of a black hole merger

    Science.gov (United States)

    Emparan, Roberto; Martínez, Marina

    2016-08-01

    We argue that the event horizon of a binary black hole merger, in the extreme-mass-ratio limit where one of the black holes is much smaller than the other, can be described in an exact analytic way. This is done by tracing in the Schwarzschild geometry a congruence of null geodesics that approaches a null plane at infinity. Its form can be given explicitly in terms of elliptic functions, and we use it to analyze and illustrate the time-evolution of the horizon along the merger. We identify features such as the line of caustics at which light rays enter the horizon, and the critical point at which the horizons touch. We also compute several quantities that characterize these aspects of the merger.

  1. KEDUDUKAN HUKUM KARYAWAN BANK PASCA DILAKUKAN MERGER, KONSOLIDASI DAN AKUISISI

    Directory of Open Access Journals (Sweden)

    Misranto

    2007-05-01

    Full Text Available One of the terms of economic crisis in Indonesia is monetary crisis. Monetary crisis or economic up to now still occur in Indonesia, which is noted by banks which undergo liquidity that causes the banks “willing or not, wanting or not” have to throw away its stirring and shake hands with the other banks to build cooperation or to look for strategic partner in order to survive by doing merger consolidation, and bank acquisition. However, the member of merger banks should notice the effects of law appeared due to merger consolidating, and that acquisition, in addition to its bank employees, because the employees have the full control as the bank operational. Bank is impossible having its activity well without full supports of its employees.

  2. Employer-provided health insurance and hospital mergers.

    Science.gov (United States)

    Garmon, Christopher

    2013-07-01

    This paper explores the impact of employer-provided health insurance on hospital competition and hospital mergers. Under employer-provided health insurance, employer executives act as agents for their employees in selecting health insurance options for their firm. The paper investigates whether a merger of hospitals favored by executives will result in a larger price increase than a merger of competing hospitals elsewhere. This is found to be the case even when the executive has the same opportunity cost of travel as her employees and even when the executive is the sole owner of the firm, retaining all profits. This is consistent with the Federal Trade Commission's findings in its challenge of Evanston Northwestern Healthcare's acquisition of Highland Park Hospital. Implications of the model are further tested with executive location data and hospital data from Florida and Texas.

  3. A Framework for Understanding Post-Merger Information Systems Integration

    DEFF Research Database (Denmark)

    Alaranta, Maria; Kautz, Karlheinz

    2012-01-01

    This paper develops a theoretical framework for the integration of information systems (IS) after a merger or an acquisition. The framework integrates three perspectives: a structuralist, an individualist, and an interactive process perspective to analyze and understand such integrations....... The framework is applied to a longitudinal case study of a manufacturing company that grew through an acquisition. The management decided to integrate the production control IS via tailoring a new system that blends together features of existing IS. The application of the framework in the case study confirms...... several known impediments to IS integrations. It also identifies a number of new inhibitors, as well as known and new facilitators that can bring post-merger IS integration to a success. Our findings provide relevant insights to researching and managing post-merger IS integrations. They emphasize...

  4. Astrophysics of Super-massive Black Hole Mergers

    CERN Document Server

    Schnittman, Jeremy D

    2013-01-01

    We present here an overview of recent work in the subject of astrophysical manifestations of super-massive black hole (SMBH) mergers. This is a field that has been traditionally driven by theoretical work, but in recent years has also generated a great deal of interest and excitement in the observational astronomy community. In particular, the electromagnetic (EM) counterparts to SMBH mergers provide the means to detect and characterize these highly energetic events at cosmological distances, even in the absence of a space-based gravitational-wave observatory. In addition to providing a mechanism for observing SMBH mergers, EM counterparts also give important information about the environments in which these remarkable events take place, thus teaching us about the mechanisms through which galaxies form and evolve symbiotically with their central black holes.

  5. BRIGHT 'MERGER-NOVA' FROM THE REMNANT OF A NEUTRON STAR BINARY MERGER: A SIGNATURE OF A NEWLY BORN, MASSIVE, MILLISECOND MAGNETAR

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yun-Wei [Institute of Astrophysics, Central China Normal University, Wuhan 430079 (China); Zhang, Bing; Gao, He, E-mail: yuyw@mail.ccnu.edu.cn, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2013-10-20

    A massive millisecond magnetar may survive the merger of a neutron star (NS) binary, which would continuously power the merger ejecta. We develop a generic dynamic model for the merger ejecta with energy injection from the central magnetar. The ejecta emission (the {sup m}erger-nova{sup )} powered by the magnetar peaks in the UV band and the peak of the light curve, progressively shifts to an earlier epoch with increasing frequency. A magnetar-powered merger-nova could have an optical peak brightness comparable to a supernova, which is a few tens or hundreds times brighter than the radioactive-powered merger-novae (the so-called macro-nova or kilo-nova). On the other hand, such a merger-nova would peak earlier and have a significantly shorter duration than that of a supernova. An early collapse of the magnetar could suppress the brightness of the optical emission and shorten its duration. Such millisecond-magnetar-powered merger-novae may be detected from NS-NS merger events without an observed short gamma-ray burst, and could be a bright electromagnetic counterpart for gravitational wave bursts due to NS-NS mergers. If detected, it suggests that the merger leaves behind a massive NS, which has important implications for the equation-of-state of nuclear matter.

  6. Valuation of Company Merger from the Shareholders’ Point of View

    Directory of Open Access Journals (Sweden)

    Christian Toll

    2017-08-01

    Full Text Available By means of a company merger formerly legally and economically independent companies are tied up to an economic entity. To order the financial state of affairs after the merger, the current shareholders must revalue their stake in the merged company. The interest is focused on the valuation of shares and, consequently, on the allocation of the future economic benefits of the merged company to each owner. Despite the apparent relevance of company mergers in practice, the scientific literature deals with this topic only in an unsatisfying manner. After some early simple model-oriented approaches with the aim to define an ideal exchange ratio, the valuation problem of a merger was taken up again not earlier than in Hering (2004. Based on his considerations, the aim of our paper is to extend and generalize the valuation methods for a company merger and foremost to set the algebra for the computation of the critical share by using maximization of wealth as target function on a firm foundation. We assign a certain marginal quota to the shareholders representing the minimum share in the merged company which puts them in a financial position no worse than compared to the going concern basis. For this reason, we introduce the state marginal quota model as an innovative valuation approach that considers both existing market imperfections and individual expectations of a specific shareholder. To pinpoint our key finding: If private financial redistributions are available, our extended and generalized model shows that the marginal quota * in question cannot be “trivially” obtained as a ratio of utilities. Instead, it is essential to consider the private decision field of a shareholder to allow a restructuring of the dividend payout stream offered by the merged company in order to reach at least a level of utility which is comparable to the state before the merger.

  7. Dynamical mass ejection from binary neutron star mergers

    Science.gov (United States)

    Radice, David; Galeazzi, Filippo; Lippuner, Jonas; Roberts, Luke F.; Ott, Christian D.; Rezzolla, Luciano

    2016-08-01

    We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation of state. We study the dynamical mass ejection from both quasi-circular and dynamical-capture eccentric mergers. We systematically vary the level of our treatment of the microphysics to isolate the effects of neutrino cooling and heating and we compute the nucleosynthetic yields of the ejecta. We find that eccentric binaries can eject significantly more material than quasi-circular binaries and generate bright infrared and radio emission. In all our simulations the outflow is composed of a combination of tidally- and shock-driven ejecta, mostly distributed over a broad ˜60° angle from the orbital plane, and, to a lesser extent, by thermally driven winds at high latitudes. Ejecta from eccentric mergers are typically more neutron rich than those of quasi-circular mergers. We find neutrino cooling and heating to affect, quantitatively and qualitatively, composition, morphology, and total mass of the outflows. This is also reflected in the infrared and radio signatures of the binary. The final nucleosynthetic yields of the ejecta are robust and insensitive to input physics or merger type in the regions of the second and third r-process peaks. The yields for elements on the first peak vary between our simulations, but none of our models is able to explain the Solar abundances of first-peak elements without invoking additional first-peak contributions from either neutrino and viscously-driven winds operating on longer time-scales after the mergers, or from core-collapse supernovae.

  8. Massive black hole and gas dynamics in galaxy nuclei mergers - I. Numerical implementation

    Science.gov (United States)

    Lupi, Alessandro; Haardt, Francesco; Dotti, Massimo

    2015-01-01

    Numerical effects are known to plague adaptive mesh refinement (AMR) codes when treating massive particles, e.g. representing massive black holes (MBHs). In an evolving background, they can experience strong, spurious perturbations and then follow unphysical orbits. We study by means of numerical simulations the dynamical evolution of a pair MBHs in the rapidly and violently evolving gaseous and stellar background that follows a galaxy major merger. We confirm that spurious numerical effects alter the MBH orbits in AMR simulations, and show that numerical issues are ultimately due to a drop in the spatial resolution during the simulation, drastically reducing the accuracy in the gravitational force computation. We therefore propose a new refinement criterion suited for massive particles, able to solve in a fast and precise way for their orbits in highly dynamical backgrounds. The new refinement criterion we designed enforces the region around each massive particle to remain at the maximum resolution allowed, independently upon the local gas density. Such maximally resolved regions then follow the MBHs along their orbits, and effectively avoids all spurious effects caused by resolution changes. Our suite of high-resolution, AMR hydrodynamic simulations, including different prescriptions for the sub-grid gas physics, shows that the new refinement implementation has the advantage of not altering the physical evolution of the MBHs, accounting for all the non-trivial physical processes taking place in violent dynamical scenarios, such as the final stages of a galaxy major merger.

  9. CANDELS: Constraining the AGN-Merger Connection with Host Morphologies at z~2

    CERN Document Server

    Kocevski, Dale D; Mozena, Mark; Koekemoer, Anton M; Nandra, Kirpal; Rangel, Cyprian; Laird, Elise S; Brusa, Marcella; Wuyts, Stijn; Trump, Jonathan R; Koo, David C; Somerville, Rachel S; Bell, Eric F; Lotz, Jennifer M; Alexander, David M; Bournaud, Frederic; Conselice, Christopher J; Dahlen, Tomas; Dekel, Avashi; Donley, Jennifer L; Dunlop, James S; Finoguenov, Alexis; Georgakakis, Antonis; Giavalisco, Mauro; Guo, Yicheng; Grogin, Norman A; Hathi, Nimish P; Juneau, Stephanie; Kartaltepe, Jeyhan S; Lucas, Ray A; McGrath, Elizabeth J; McIntosh, Daniel H; Mobasher, Bahram; Robaina, Aday R; Rosario, David; Straughn, Amber N; van der Wel, Arjen; Villforth, Carolin

    2011-01-01

    Using HST/WFC3 imaging taken as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), we examine the role that major galaxy mergers play in triggering active galactic nuclei (AGN) activity at z~2. Our sample consists of 72 moderate-luminosity (Lx ~ 1E42-1E44 erg/s) AGN at 1.5major merger or interaction, while most of the hosts (55.6%) appear relatively relaxed and undisturbed. These fractions are statistically consis...

  10. Towards a Novel Conceptual Framework for Understanding Mergers in Higher Education

    Science.gov (United States)

    Cai, Yuzhuo; Pinheiro, Rómulo; Geschwind, Lars; Aarrevaara, Timo

    2016-01-01

    This paper tries to develop a conceptual framework for a comprehensive understanding of the merger process, which is regarded as a matter of institutionalization of organizational innovation. In the framework, a number of factors affecting merger process or institutionalization of merger are identified, such as those related to environmental…

  11. 17 CFR 230.145 - Reclassification of securities, mergers, consolidations and acquisitions of assets.

    Science.gov (United States)

    2010-04-01

    ..., mergers, consolidations and acquisitions of assets. 230.145 Section 230.145 Commodity and Securities... § 230.145 Reclassification of securities, mergers, consolidations and acquisitions of assets.... A statutory merger or consolidation or similar plan or acquisition in which securities of...

  12. The InBev and Anheuser-Busch Merger in China: A View from Economists

    OpenAIRE

    Howard Chang; Xinzhu Zhang

    2008-01-01

    In this paper, we provide some background on the merger approval process in China and the InBev acquisition, and then discuss the implications of MOFCOM’s decision and its other statements on merger policy for the future of merger control in China.

  13. From discs to bulges: effect of mergers on the morphology of galaxies

    NARCIS (Netherlands)

    Kannan, Rahul; Macciò, Andrea V.; Fontanot, Fabio; Moster, Benjamin P.; Karman, Wouter; Somerville, Rachel S.

    2015-01-01

    We study the effect of mergers on the morphology of galaxies by means of the simulated merger tree approach first proposed by Moster et al. This method combines N-body cosmological simulations and semi-analytic techniques to extract realistic initial conditions for galaxy mergers. These are then evo

  14. Bazaarvoice: Applying Traditional Merger Analysis to a Dynamic High-Tech Market

    OpenAIRE

    James Fishkin

    2014-01-01

    No one should be surprised that the government will investigate mergers involving products in a high-tech industry utilizing the same Horizontal Merger Guidelines that apply to all merger investigationsâ۠regardless of the industry. James A. Fishkin (Dechert LLP)

  15. Mergers between governmental research institutes and Universities in the Danish HE sector

    DEFF Research Database (Denmark)

    Aagaard, Kaare; Hansen, Hanne Foss; Rasmussen, Jørgen Gulddahl

    2016-01-01

    This article presents an analysis of the mergers in the Danish Higher Education (HE)-sector with a particular emphasis on the 2007 mergers involving universities and Government Research Institutes (GRIs). Furthermore, it follows the post-merger processes up to 2014/2015 at two Danish universities...

  16. Discursive "Policy Logics" of Mergers in US Higher Education: Strategy or Tragedy?

    Science.gov (United States)

    Stephenson, Sandria S.

    2011-01-01

    Mergers are part of the historical fabric of US higher education. However, the current economic recession and other policy issues have experts and academicians predicting an increase in higher education mergers in the USA. Consequently, this study analysed the discursive "policy logics" surrounding merger negotiations in US higher education. The…

  17. Mergers and aquisitions in India:motives,barriers and outcomes

    OpenAIRE

    Shah, Siddharth

    2012-01-01

    This paper examines the various factors that need to be accounted for while analysing a company undertaking a merger or an acquisition. From the motives behind the decisions to enter into a Merger or Acquisition to the barriers it faces during the process to the immediate as well as future outcomes have been projected in this research. Four case studies have been analysed showing the overall picture of the deal, the cases were: The TataCorus acquisition, The BhartiAirtel and Zain acquisi...

  18. Post-Merger Restructuring and the Boundaries of the Firm

    OpenAIRE

    Vojislav Maksimovic; Gordon Phillips; N. R. Prabhala

    2008-01-01

    Mergers and acquisitions are a fast way for a firm to grow. Using plant-level data, we examine how firms redraw their boundaries after acquisitions. We find that there is a large amount of restructuring in a short period following mergers. Acquirers sell 27% and close 19% of acquired plants within three years of the acquisition. Plants in the target's peripheral divisions, especially in industries in which asset values are increasing, and in industries in which the acquirer does not have a co...

  19. Metallicity evolution in mergers of disk galaxies with black holes

    Science.gov (United States)

    Rantala, Antti; Johansson, Peter H.

    2016-10-01

    We use the TreeSPH simulation code Gadget-3 including a recently improved smoothed particle hydrodynamics (SPH) module, a detailed metallicity evolution model and sophisticated subresolution feedback models for supernovae and supermassive black holes in order to study the metallicity evolution in disk galaxy mergers. In addition, we examine the simulated morphology, star formation histories, metallicity gradients and kinematic properties of merging galaxies and merger remnants. We will compare our simulation results with observations of the early-type Centaurus A galaxy and the currently colliding Antennae galaxies.

  20. Hospital mergers and acquisitions: does market consolidation harm patients?

    Science.gov (United States)

    Ho, V; Hamilton, B H

    2000-09-01

    Debate continues on whether consolidation in health care markets enhances efficiency or instead facilitates market power, possibly damaging quality. We compare the quality of hospital care before and after mergers and acquisitions in California between 1992 and 1995. We analyze inpatient mortality for heart attack and stroke patients, 90-day readmission for heart attack patients, and discharge within 48 h for normal newborn babies. Recent mergers and acquisitions have not had a measurable impact on inpatient mortality, although the associated standard errors are large. Readmission rates and early discharge increased in some cases. The adverse consequences of increased market power on the quality of care require further substantiation.

  1. Galaxy Merger Candidates in High-redshift Cluster Environments

    Science.gov (United States)

    Delahaye, A. G.; Webb, T. M. A.; Nantais, J.; DeGroot, A.; Wilson, G.; Muzzin, A.; Yee, H. K. C.; Foltz, R.; Noble, A. G.; Demarco, R.; Tudorica, A.; Cooper, M. C.; Lidman, C.; Perlmutter, S.; Hayden, B.; Boone, K.; Surace, J.

    2017-07-01

    We compile a sample of spectroscopically and photometrically selected cluster galaxies from four high-redshift galaxy clusters (1.59contamination from interlopers, {11.0}-5.6+7.0 % of the cluster members are involved in potential mergers, compared to {24.7}-4.6+5.3 % of the field galaxies. We see no evidence of merger enhancement in the central cluster environment with respect to the field, suggesting that galaxy-galaxy merging is not a stronger source of galaxy evolution in cluster environments compared to the field at these redshifts.

  2. The impact of post-merger cross-shareholdings on South African merger control policy

    Directory of Open Access Journals (Sweden)

    Chris Charter

    2012-10-01

    Full Text Available There is a concentration of EU and US standards in the South African economy. In addition, a number of large industries have been undergoing consolidation. As a result, the phenomenon of cross-holdings, both within and across industries, is not unusual. In cases where the level of cross-holding falls short of joint control, the competition authorities have at times sought to apply the co-ordinated effects doctrine or some variation thereof hoping to lessen potential competition. More recently, the Tribunal has also considered the possible unilateral effects of the acquisition of a minority stake in a rival. A number of cases has emerged that to a greater or lesser degree explores the impact of crossholdings and cross-directorships on the competitive behaviour of the firms concerned. This paper includes a review of some of these decisions with a view to determining whether any clear policy seems likely to emerge from the competition authorities. The authorities’ approach to date, reveals an evolution from reflex suspicion to a more reasoned, fact-based outlook. Cross-holdings and directorships are treated in the same way as any other evidence relevant to an analysis of a given merger. However, despite the Tribunal’s willingness to wrestle with various economic theories, the most recent decision suggests that the acquisition of a non-controlling cross-holding in a company may not fall under the analysis of South African merger regulation at all. Should that position change, following clarification by the Tribunal or an unequivocal ruling of the Competition Appeal Court, the body of case law goes some way to indicating the type and manner of analysis the authorities will employ.

  3. A Study on Firm Mergers One of the Financial Structure Strengthening Precautions: Tansaş-Migros Merger

    Directory of Open Access Journals (Sweden)

    Berna YILDIZ TULUM

    2009-06-01

    Full Text Available In last years, it is examined that there is an increase in the number of firms that faces with financial distress in both our country and in west. In terms of social and economic results, the financial distress of the firms is a very big problem. Consequently, financial distress prediction carries an very big importance. By forecasting the probability of facing with financial distress, the firms can be able to catch the opportunity of taking necessary financial structure strengthening precautions. Firm mergers is one of the many financial structure strengthening precautions. This study aims to improve models that provides the prediction of financial distress 1-3 years before in firms that is active in retail sector and have transactions in IMKB by showing the firm mergers which is one of the financial structure strengthening precautions in Tansaş and Migros Merger in retail sector.

  4. Tracing kinematic (mis)alignments in CALIFA merging galaxies: Stellar and ionized gas kinematic orientations at every merger stage

    CERN Document Server

    Barrera-Ballesteros, J K; Falcón-Barroso, J; van de Ven, G; Lyubenova, M; Wild, V; Méndez-Abreu, J; Sánchez, S F; Marquez, I; Masegosa, J; Monreal-Ibero, A; Ziegler, B; del Olmo, A; Verdes-Montenegro, L; García-Benito, R; Husemann, B; Mast, D; Kehrig, C; Iglesias-Paramo, J; Marino, R A; Aguerri, J A L; Walcher, C J; Vílchez, J M; Bomans, D J; Cortijo-Ferrero, C; Delgado, R M González; Bland-Hawthorn, J; McIntosh, D H; Bekeraite, Simona

    2015-01-01

    We present spatially resolved stellar and/or ionized gas kinematic properties for a sample of 103 interacting galaxies, tracing all merger stages: close companions, pairs with morphological signatures of interaction, and coalesced merger remnants. We compare our sample with 80 non-interacting galaxies. We measure for the stellar and the ionized gas components the major (projected) kinematic position angles (PA$_{\\mathrm{kin}}$, approaching and receding) directly from the velocity fields with no assumptions on the internal motions. This method allow us to derive the deviations of the kinematic PAs from a straight line ($\\delta$PA$_{\\mathrm{kin}}$). Around half of the interacting objects show morpho-kinematic PA misalignments that cannot be found in the control sample. Those misalignments are present mostly in galaxies with morphological signatures of interaction. Alignment between the kinematic sides for both samples is similar, with most of the galaxies displaying small misalignments. Radial deviations of the...

  5. Type Ia supernovae from violent mergers of carbon-oxygen white dwarfs: polarization signatures

    Science.gov (United States)

    Bulla, M.; Sim, S. A.; Pakmor, R.; Kromer, M.; Taubenberger, S.; Röpke, F. K.; Hillebrandt, W.; Seitenzahl, I. R.

    2016-01-01

    The violent merger of two carbon-oxygen white dwarfs has been proposed as a viable progenitor for some Type Ia supernovae. However, it has been argued that the strong ejecta asymmetries produced by this model might be inconsistent with the low degree of polarization typically observed in Type Ia supernova explosions. Here, we test this claim by carrying out a spectropolarimetric analysis for the model proposed by Pakmor et al. for an explosion triggered during the merger of a 1.1 and 0.9 M⊙ carbon-oxygen white dwarf binary system. Owing to the asymmetries of the ejecta, the polarization signal varies significantly with viewing angle. We find that polarization levels for observers in the equatorial plane are modest (≲1 per cent) and show clear evidence for a dominant axis, as a consequence of the ejecta symmetry about the orbital plane. In contrast, orientations out of the plane are associated with higher degrees of polarization and departures from a dominant axis. While the particular model studied here gives a good match to highly polarized events such as SN 2004dt, it has difficulties in reproducing the low polarization levels commonly observed in normal Type Ia supernovae. Specifically, we find that significant asymmetries in the element distribution result in a wealth of strong polarization features that are not observed in the majority of currently available spectropolarimetric data of Type Ia supernovae. Future studies will map out the parameter space of the merger scenario to investigate if alternative models can provide better agreement with observations.

  6. Merger-driven evolution of the effective stellar initial mass function of massive early-type galaxies

    CERN Document Server

    Sonnenfeld, Alessandro; Treu, Tommaso

    2016-01-01

    The stellar initial mass function (IMF) of early-type galaxies is the combination of the IMF of the stellar population formed in-situ and that of accreted stellar populations. Using as an observable the effective IMF $\\alpha_{IMF}$, defined as the ratio between the true stellar mass of a galaxy and the stellar mass inferred assuming a Salpeter IMF, we present a theoretical model for its evolution as a result of dry mergers. We use a simple dry merger evolution model, based on cosmological $N$-body simulations, together with empirically motivated prescriptions for the IMF to make predictions for how the effective IMF of massive early-type galaxies changes from $z=2$ to $z=0$. We find that the IMF normalization of individual galaxies becomes lighter with time. At fixed velocity dispersion, $\\alpha_{IMF}$ is predicted to be constant with redshift. Current constraints on the evolution of the IMF are in slight tension with this prediction, even though systematic uncertainties prevent a conclusive statement. The co...

  7. Mergers & Acquisitions in Japan : Lessons for Dutch companies

    NARCIS (Netherlands)

    Grotenhuis, F.D.J.

    2009-01-01

    This article deals with lessons learned from mergers and acquisitions in Japan. In general, such combinations are not success stories, since 50–80 percent of them do not bring the benefits that were expected. Several reasons for such failures have been brought up in the literature, but real-life cas

  8. Numerical Relativity, Black Hole Mergers, and Gravitational Waves: Part I

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    This series of 3 lectures will present recent developments in numerical relativity, and their applications to simulating black hole mergers and computing the resulting gravitational waveforms. In this first lecture, we introduce the basic ideas of numerical relativity, highlighting the challenges that arise in simulating gravitational wave sources on a computer.

  9. Numerical Relativity, Black Hole Mergers, and Gravitational Waves: Part III

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    This series of 3 lectures will present recent developments in numerical relativity, and their applications to simulating black hole mergers and computing the resulting gravitational waveforms. In this third and final lecture, we present applications of the results of numerical relativity simulations to gravitational wave detection and astrophysics.

  10. The Scanfin Merger: Managing Organisational Change (Case C)

    DEFF Research Database (Denmark)

    Smith, Pernille; Carugati, Andrea; Giangreco, Antonio

    the integration process of the merger. The main issue is how a middle manager constitutes an obstacle to this organisational change by re-inforcing the 'old' ways of working in his group. To solve this case satisfactorily students should be able to see the organisation from several different layers (employee...

  11. Is your hospital a candidate for a merger or acquisition?

    Science.gov (United States)

    Ashworth, R B; Hirsch, N G

    1983-05-01

    Decisions to buy or sell a hospital or to merge with another facility raise concerns for any institution, be it the buyer, the seller, or the proposed partner in the merger. To help trustees assess their options, this article presents profiles of the common characteristics shared by institutions that have been acquired and by those that have acquired other institutions.

  12. EFFECTIVE SCHEMES OF FINANCING MERGERS AND ACQUISITIONS OF INTERNATIONAL CORPORATIONS

    Directory of Open Access Journals (Sweden)

    Vladimir Momot

    2013-10-01

    Full Text Available The article considers the question of a choice of the optimum scheme of financing mergers and acquisitions (M&As in the environment of international corporations. Methods and ways of financing integration transactions are considered and key factors and system processes of realization of these transactions are defined.

  13. Merger as marriage: communication issues in postmerger integration.

    Science.gov (United States)

    Dooley, Kevin J; Zimmerman, Brenda J

    2003-01-01

    Many health care organizations have found themselves involved in mergers, acquisitions, alliances, networks, and other forms of structural change in order to reduce costs, improve utilization and service breadth, increase market leverage, and reduce variation in demand. This article examines three levels of communication issues that interact with one another and impact the likelihood of successful postmerger integration: affect, discursive frame, and negotiating position.

  14. Merger, Akusisi dan Konsolidasi dalam Perspektif Hukum Persaingan Usaha

    Directory of Open Access Journals (Sweden)

    Paulus Aluk Fajar Dwi Santo

    2011-05-01

    Full Text Available Mergers, acquisitions and consolidation is a business strategy that is commonly used in the business world to be able to build competitive advantage company, which in time can enhance shareholder value while maximizing the prosperity of the company owners or shareholders. To achieve the above objective normative, policy-makers need a plan and steps of strategic and accurate information to avoid the risk of failure. However, the strategy of merger, acquisition and consolidation of certain potentially inhibit fair competition conditions, thus becoming one of the objects that need to be regulated in Law no. 5 Year 1999 concerning Prohibition of Monopolistic Practices and Unfair Business Competition. Market impact of mergers, acquisitions and consolidation is important for analysis because it can have significant legal consequences for businesses, so that the research method used is the juridical normative and empirical approaches. In practice of mergers, acquisitions and consolidation intersect with regulation in other sectors, especially banking and capital markets. That is, there should be equality of perception and interpretation among the institutions that issued the policy.

  15. Organisational mergers: a behavioural perspective on identity management

    NARCIS (Netherlands)

    S.R. Giessner (Steffen)

    2016-01-01

    markdownabstractOrganisational mergers are one of the most extreme forms of organisational change processes. Consequently, they often result in difficulties for employees to adjust to the altered organisational conditions. This is often reflected in low levels of employee identification with the

  16. 7 CFR 1710.108 - Mergers and consolidations.

    Science.gov (United States)

    2010-01-01

    ... operating efficiency and financial soundness. (b) After a merger or consolidation, RUS will give priority consideration per § 1710.119 to the processing of loans for the surviving system to finance the integration and... rural areas. Such priority consideration will also be given in the case of a borrower that has merged or...

  17. 12 CFR 611.1123 - Merger or consolidation agreements.

    Science.gov (United States)

    2010-01-01

    ... benefits plan, its subsequent continuation or adaptation by the board of directors of the proposed..., Consolidations, and Charter Amendments of Associations § 611.1123 Merger or consolidation agreements. (a... employees that is a party to the proposed transactions. (7) A statement that the board of directors of...

  18. Downsizings, Mergers, and Acquisitions: Perspectives of Human Resource Development Practitioners

    Science.gov (United States)

    Shook, LaVerne; Roth, Gene

    2011-01-01

    Purpose: This paper seeks to provide perspectives of HR practitioners based on their experiences with mergers, acquisitions, and/or downsizings. Design/methodology/approach: This qualitative study utilized interviews with 13 HR practitioners. Data were analyzed using a constant comparative method. Findings: HR practitioners were not involved in…

  19. Organisational mergers: a behavioural perspective on identity management

    NARCIS (Netherlands)

    S.R. Giessner (Steffen)

    2016-01-01

    markdownabstractOrganisational mergers are one of the most extreme forms of organisational change processes. Consequently, they often result in difficulties for employees to adjust to the altered organisational conditions. This is often reflected in low levels of employee identification with the p

  20. Binary Black Hole Mergers, Gravitational Waves, and LISA

    Science.gov (United States)

    Centrella, Joan; Baker, J.; Boggs, W.; Kelly, B.; McWilliams, S.; van Meter, J.

    2007-12-01

    The final merger of comparable mass binary black holes is expected to be the strongest source of gravitational waves for LISA. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. We will present the results of new simulations of black hole mergers with unequal masses and spins, focusing on the gravitational waves emitted and the accompanying astrophysical "kicks.” The magnitude of these kicks has bearing on the production and growth of supermassive blackholes during the epoch of structure formation, and on the retention of black holes in stellar clusters. This work was supported by NASA grant 06-BEFS06-19, and the simulations were carried out using Project Columbia at the NASA Advanced Supercomputing Division (Ames Research Center) and at the NASA Center for Computational Sciences (Goddard Space Flight Center).

  1. Downsizings, Mergers, and Acquisitions: Perspectives of Human Resource Development Practitioners

    Science.gov (United States)

    Shook, LaVerne; Roth, Gene

    2011-01-01

    Purpose: This paper seeks to provide perspectives of HR practitioners based on their experiences with mergers, acquisitions, and/or downsizings. Design/methodology/approach: This qualitative study utilized interviews with 13 HR practitioners. Data were analyzed using a constant comparative method. Findings: HR practitioners were not involved in…

  2. Built to Be Excellent? The Aalto University Merger in Finland

    Science.gov (United States)

    Tienari, Janne; Aula, Hanna-Mari; Aarrevaara, Timo

    2016-01-01

    In the Finnish higher education system, government steering and the interests of industry and business have come to focus on the impact of the university in society. In 2010, "Aalto University" was created in a merger of three universities representing different academic fields. The new university developed a forward-looking strategy,…

  3. Can mergers-in-progress be unmerged in speech accommodation?

    Directory of Open Access Journals (Sweden)

    Molly eBabel

    2013-09-01

    Full Text Available This study examines spontaneous phonetic accommodation of a dialect with distinct categories by speakers who are in the process of merging those categories. We focus on the merger of the NEAR and SQUARE lexical sets in New Zealand English, presenting New Zealand participants with an unmerged speaker of Australian English. Mergers-in-progress are a uniquely interesting sound change as they showcase the asymmetry between speech perception and production. Yet, we examine mergers using spontaneous phonetic imitation, which is phenomenon that is necessarily a behavior where perceptual input influences speech production. Phonetic imitation is quantified by a perceptual measure and an acoustic calculation of mergedness using a Pillai-Bartlett trace. The results from both analyses indicate spontaneous phonetic imitation is moderated by extra-linguistic factors such as the valence of assigned conditions and social bias. We also find evidence for a decrease in the degree of mergedness in post-exposure productions. Taken together, our results suggest that under the appropriate conditions New Zealanders phonetically accommodate to Australian English and that in the process of speech imitation, mergers-in-progress can, but do not consistently, become less merged.

  4. The Fate of the Compact Remnant in Neutron Star Mergers

    CERN Document Server

    Fryer, Chris L; Ramirez-Ruiz, Enrico; Rosswog, Stephan; Shen, Gang; Steiner, Andrew W

    2015-01-01

    Neutron star (binary neutron star and neutron star - black hole) mergers are believed to produce short-duration gamma-ray bursts. They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of merger calculations and equation of state studies to determine the fate of the cores of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3-2.4 solar masses. If quick black hole formation is essential in producing gamma-ray bursts, LIGO observed rates compared to GRB rates could be used to constr...

  5. THE FATE OF THE COMPACT REMNANT IN NEUTRON STAR MERGERS

    Energy Technology Data Exchange (ETDEWEB)

    Fryer, Chris L. [Department of Physics, The University of Arizona, Tucson, AZ 85721 (United States); Belczynski, Krzysztoff [Astronomical Observatory, University of Warsaw, Al Ujazdowskie 4, 00-478 Warsaw (Poland); Ramirez-Ruiz, Enrico [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Rosswog, Stephan [The Oskar klein Center, Department of Astronomy, AlbaNova, Stockholm University, SE-106 91 Stockholm (Sweden); Shen, Gang [Institute for Nuclear Theory, University of Washington, Seattle, WA 98195 (United States); Steiner, Andrew W. [Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996 (United States)

    2015-10-10

    Neutron star (binary neutron star and neutron star–black hole) mergers are believed to produce short-duration gamma-ray bursts (GRBs). They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and advanced VIRGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of Newtonian merger calculations and equation of state studies to determine the fate of the cores of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3–2.4 solar masses. If quick black hole formation is essential in producing GRBs, LIGO/Virgo observed rates compared to GRB rates could be used to constrain the equation of state for dense nuclear matter.

  6. Binary Black Hole Mergers, Gravitational Waves, and LISA

    Science.gov (United States)

    Centrella, Joan; Baker, J.; Boggs, W.; Kelly, B.; McWilliams, S.; vanMeter, J.

    2008-01-01

    The final merger of comparable mass binary black holes is expected to be the strongest source of gravitational waves for LISA. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. We will present the results of new simulations of black hole mergers with unequal masses and spins, focusing on the gravitational waves emitted and the accompanying astrophysical "kicks." The magnitude of these kicks has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters.

  7. Observing mergers of non-spinning black-hole binaries

    CERN Document Server

    McWilliams, Sean T; Baker, John G

    2010-01-01

    Advances in the field of numerical relativity now make it possible to calculate the final, most powerful merger phase of binary black-hole coalescence for generic binaries. The state of the art has advanced well beyond the equal-mass case into the unequal-mass and spinning regions of parameter space. We present a study of the nonspinning portion of parameter space, primarily using an analytic waveform model tuned to available numerical data, with an emphasis on observational implications. We investigate the impact of varied mass ratio on merger signal-to-noise ratios (SNRs) for several detectors, and compare our results with expectations from the test-mass limit. We note a striking similarity of the waveform phasing of the merger waveform across the available mass ratios. Motivated by this, we calculate the match between our 1:1 (equal mass) and 4:1 mass-ratio waveforms during the merger as a function of location on the source sky, using a new formalism for the match that accounts for higher harmonics. This i...

  8. Mergers & Acquisitions in Japan : Lessons for Dutch companies

    NARCIS (Netherlands)

    Grotenhuis, F.D.J.

    2009-01-01

    This article deals with lessons learned from mergers and acquisitions in Japan. In general, such combinations are not success stories, since 50–80 percent of them do not bring the benefits that were expected. Several reasons for such failures have been brought up in the literature, but real-life

  9. COMPLEMENTARITY AND SIMILARITY OF PARTNERS IN INTERNATIONAL MERGERS

    NARCIS (Netherlands)

    Van Oudenhoven, J.P.; Boer, Th

    1995-01-01

    The effects of degree of cultural and strategic similarity on the preference for a potential merger candidate were investigated. The main objective of the study was to test predictions based on the similarity-attraction hypothesis, Bryne and Clore's (1970) reinforcement-affect model, and social iden

  10. Dynamical Mass Ejection from Binary Neutron Star Mergers

    CERN Document Server

    Radice, David; Lippuner, Jonas; Roberts, Luke F; Ott, Christian D; Rezzolla, Luciano

    2016-01-01

    We present fully general-relativistic simulations of binary neutron star mergers with a temperature and composition dependent nuclear equation of state. We study the dynamical mass ejection from both quasi-circular and dynamical-capture eccentric mergers. We systematically vary the level of our treatment of the microphysics to isolate the effects of neutrino cooling and heating and we compute the nucleosynthetic yields of the ejecta. We find that eccentric binaries can eject significantly more material than quasi-circular binaries and generate bright infrared and radio emission. In all our simulations the outflow is composed of a combination of tidally- and shock-driven ejecta, mostly distributed over a broad $\\sim 60^\\circ$ angle from the orbital plane, and, to a lesser extent, by thermally driven winds at high latitudes. Ejecta from eccentric mergers are typically more neutron rich than those of quasi-circular mergers. This is the effect of the strong tidal torques exerted on the neutron stars during their ...

  11. Impact of Mergers and Acquisitions on the Performance of ...

    African Journals Online (AJOL)

    DR Nneka

    Based on our findings it was recommended that- there should be adequate supervision ... approach has really improved the manufacturing sector and the economy. Reports ... Alashi (2003) suggest that alliances are more flexible unions of which ... Mergers and acquisition is one of the survival strategies of a business. As a.

  12. The Efficiency of the Regulation for Horizontal Mergers Among Electricity Distribution Operators in Norway

    DEFF Research Database (Denmark)

    Agrell, Per J.; Bogetoft, Peter; Gammeltvedt, Thor Erik

    2015-01-01

    Merger analysis is usually drawing on concepts derived from competitive horizontal markets, such as market concentration, predatory foreclosure and economies of scale in marketing. In evaluating horizontal mergers among energy network operators, regulators must use different tools to evaluate...... the attractiveness of mergers. Norway is one country having implemented an ex ante regulation for mergers among electricity distribution operators (DSOs). We investigate whether the actual mergers of Norwegian DSOs in the period 1995-2004 can be rationalized as cost saving exercises or whether they should...... be interpreted in other ways. We use Data Envelopment Analysis (DEA) to estimate the potential cost savings from mergers ex ante, and we decompose the gains into gains from learning best practice and from improving economies of scale and scope. Moreover, we compare the sources of post merger performance...

  13. How does competition structure affect industry merger waves? A network analysis perspective

    Science.gov (United States)

    Hou, Rui; Yang, Jianmei; Yao, Canzhong; McKelvey, Bill

    2015-07-01

    By taking China's beer industry as an example, this paper establishes a series of industrial competition-pressure networks and examines the correlation between competition structure and merger actions. We present a cascade dynamic-merger agent-based computational model driven by competition pressure diffusion to describe the forming process of industry merger wave. The empirical analyses and agent-based computational simulation results show that the competition structure among rivals has a strong effect on the scale, the duration time, and the stability of industry merger wave. We also give explanations on why there are different simulation results between in single market competition environment and in multi-market competition environment, as well as discuss the management implications for the industry-merger policy makers and the merger-tactics decision makers that are involved in merger wave.

  14. Merger Auditor dan Kualitas Audit: Bukti Empiris Dari Bursa Efek Indonesia

    Directory of Open Access Journals (Sweden)

    Sansaloni Butar-Butar

    2016-06-01

    Full Text Available Merge rof Pricewaterhouse and Coopers & Lybrands that occurred in 1998 creates PricewaterhouseCoopers as the biggest accounting firm in history. Conceptually and supported by previous empirical result firm size is expected to be positively correlated with audit quality. Large accounting firms have financial ability to improve its auditors skill and can act more independently because major part of their income do not come from one or two clients. They spend huge investment in audit technology as well. However, this positive relationship only applies to environments where punishment is strictly imposed on audit failure. Unlike their counterparts in the United States and Europe, auditors working in Indonesia rarely face legal issues related to the audit assignment. In addition, empirical studies in Indonesia have always classified local auditors as Big N auditors if they affiliate with one of Big N auditors assuming same quality with that of Big N auditors. This assumption does not necessarily hold. Therefore, in the context of Indonesia environtments, this study predicts PricewaterhouseCoopers merger does not affect the quality of the audit. Using abnormal accruals as a proxy for audit quality, the results show that after the merger audit quality has declined significantly.

  15. The Distribution of Dark and Luminous Matter in the Unique Galaxy Cluster Merger Abell 2146

    CERN Document Server

    King, Lindsay J; Coleman, Joseph E; Russell, Helen R; Santana, Rebecca; White, Jacob A; Canning, Rebecca E A; Deering, Nicole J; Fabian, Andrew C; Lee, Brandyn E; Li, Baojiu; McNamara, Brian R

    2016-01-01

    Abell 2146 ($z$ = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the $\\textit{Chandra X-ray Observatory}$, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the total gravitating mass in the system, using the distorted shapes of distant galaxies seen with ACS-WFC on $\\textit{Hubble Space Telescope}$, is presented. The highest peak in the reconstruction of the projected mass is centred on the Brightest Cluster Galaxy (BCG) in Abell 2146-A. The mass associated with Abell 2146-B is more extended. Bootstrapped noise mass reconstructions show the mass peak in Abell 2146-A to be consistently centred on the BCG. Previous work showed that BCG-A appears to lag behind an X-ray cool core; although the peak of the mass reconstruction is centred on the BCG, it is also consistent with the X-ray peak given the resolution of the we...

  16. The Role of the Kozai-Lidov Mechanism in Black Hole Binary Mergers in Galactic Centers

    CERN Document Server

    VanLandingham, John H; Hamilton, Douglas P; Richardson, Derek C

    2016-01-01

    In order to understand the rate of merger of stellar-mass black hole binaries (BHBs) by gravitational wave (GW) emission it is important to determine the major pathways to merger. We use numerical simulations to explore the evolution of BHBs inside the radius of influence of supermassive black holes (SMBHs) in galactic centers. In this region the evolution of binaries is dominated by perturbations from the central SMBH. In particular, as first pointed out by Antonini and Perets, the Kozai-Lidov (KL) mechanism trades relative inclination of the BHB to the SMBH for eccentricity of the BHB, and for some orientations can bring the BHB to an eccentricity near unity. At very high eccentricities, GW emission from the BHB can become efficient, causing the members of the BHB to coalesce. We use a novel combination of two N-body codes to follow this evolution. We are forced to simulate small systems to follow the behavior accurately. We have completed 400 simulations that range from $\\sim$ 300 stars around a $10^{3}$ M...

  17. The Response of a Circumbinary Disk to a Black Hole Merger

    Science.gov (United States)

    Haiman, Zoltan

    Finding electromagnetic counterparts of future gravitational wave sources would bring rich scientific benefits. A promising possibility, in the case of the coalescence of a super- massive black hole binary, is that prompt emission will be detectable from merger- induced disturbances in a circumbinary disk. Motivated by this possibility, we propose a major effort, to investigate the dynamical response of a circumbinary disk to the SMBH merger, and to compute the expected light-curve and spectrum of the emerging radiation. Our work will consist of several stages of increasing complexity: starting from semi- analytical orbital calculations for a collisionless disk of massless test particles, and culminating in three-dimensional simulations, with an approximate treatment of radiative transfer. The proposed collaboration is built on previous work of the PI and the Co-I, and will lead to an understanding of the physics of how the disturbed disks light up, as well as the nature of the disk emission. Our results will significantly enhance the science return from the LISA satellite, in which NASA is invested, and will directly support NASA's Strategic Plan, Sub-Goal 3D: ``Discover the origin, structure, evolution and destiny of the universe''.

  18. Merger Auditor dan Kualitas Audit: Bukti Empiris Dari Bursa Efek Indonesia

    Directory of Open Access Journals (Sweden)

    Sansaloni Butar-Butar

    2014-08-01

    Full Text Available Merge rof Pricewaterhouse and Coopers & Lybrands that occurred in 1998 creates PricewaterhouseCoopers as the biggest accounting firm in history. Conceptually and supported by previous empirical result firm size is expected to be positively correlated with audit quality. Large accounting firms have financial ability to improve its auditors skill and can act more independently because major part of their income do not come from one or two clients. They spend huge investment in audit technology as well. However, this positive relationship only applies to environments where punishment is strictly imposed on audit failure. Unlike their counterparts in the United States and Europe, auditors working in Indonesia rarely face legal issues related to the audit assignment. In addition, empirical studies in Indonesia have always classified local auditors as Big N auditors if they affiliate with one of Big N auditors assuming same quality with that of Big N auditors. This assumption does not necessarily hold. Therefore, in the context of Indonesia environtments, this study predicts PricewaterhouseCoopers merger does not affect the quality of the audit. Using abnormal accruals as a proxy for audit quality, the results show that after the merger audit quality has declined significantly.

  19. Binary neutron star merger simulations with different initial orbital frequency and equation of state

    CERN Document Server

    Maione, Francesco; Feo, Alessandra; Löffler, Frank

    2016-01-01

    We present results from three-dimensional general relativistic simulations of binary neutron star coalescences and mergers using public codes. We considered equal mass models where the baryon mass of the two Neutron Stars (NS) is $1.4M_{\\odot}$, described by four different equations of state (EOS) for the cold nuclear matter (APR4, SLy, H4, and MS1; all parametrized as piecewise polytropes). We started the simulations from four different initial interbinary distances ($40, 44.3, 50$, and $60$ km), including up to the last 16 orbits before merger. That allows to show the effects on the gravitational wave phase evolution, radiated energy and angular momentum due to: the use of different EOSs, the orbital eccentricity present in the initial data and the initial separation (in the simulation) between the two stars. Our results show that eccentricity has a major role in the discrepancy between numerical and analytical waveforms until the very last few orbits, where "tidal" effects and missing high-order post-Newto...

  20. The role of timing in a merger wave on overcoming challenges in the M&A pre-merger process

    NARCIS (Netherlands)

    Trang, T.D.; Rao Sahib, P.; van Witteloostuijn, Arjen

    This paper investigates two important issues in the pre-merger process, namely the probability to complete an announced M&A deal and the time needed to complete the process. First, through a content analysis of the 150 largest abandoned announced M&A deals between 2000 and 2010, we demonstrate that