Log in

Relevant bibliographies by topics / Semi-analytic models / Journal articles

Journal articles on the topic 'Semi-analytic models'

To see the other types of publications on this topic, follow the link: Semi-analytic models.

Author: Grafiati

Published: 1 April 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Semi-analytic models.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Lacerna, I., S. Contreras, R. E. González, N. Padilla, and V. Gonzalez-Perez. "Galactic conformity measured in semi-analytic models." Monthly Notices of the Royal Astronomical Society 475, no. 1 (December 20, 2017): 1177–89. http://dx.doi.org/10.1093/mnras/stx3253.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Hartl, Urs T. "Semi-stable models for rigid-analytic spaces." manuscripta mathematica 110, no. 3 (March 2003): 365–80. http://dx.doi.org/10.1007/s00229-002-0349-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Gruppioni, C., F. Calura, F. Pozzi, I. Delvecchio, S. Berta, G. De Lucia, F. Fontanot, et al. "Star formation inHerschel's Monsters versus semi-analytic models." Monthly Notices of the Royal Astronomical Society 451, no. 4 (June 25, 2015): 3419–26. http://dx.doi.org/10.1093/mnras/stv1204.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Visbal, Eli, Zoltán Haiman, and Greg L. Bryan. "Self-consistent semi-analytic models of the first stars." Monthly Notices of the Royal Astronomical Society 475, no. 4 (January 17, 2018): 5246–56. http://dx.doi.org/10.1093/mnras/sty142.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Donnelly, IJ, EK Rose, and JL Cook. "Magnetohydrodynamic Equilibrium Models for Rotamak Plasmas." Australian Journal of Physics 40, no. 2 (1987): 175. http://dx.doi.org/10.1071/ph870175.

Full text

Abstract:

A semi-analytic method is used to solve the Grad-Shafranov equation for a range of compact torus plasma configurations which have ellipsoidal separatrices, zero toroidal magnetic field and pressure P proportional to the square of the poloidal flux function 1[1. The equilibria are compared with the analytic solutions of the Solov'ev model, for which P ex 1[1.

APA, Harvard, Vancouver, ISO, and other styles

6

Delfino, Facundo M., Claudia G. Scóccola, Sofía A. Cora, Cristian A. Vega-Martínez, and Ignacio D. Gargiulo. "Tracking the orbit of unresolved subhaloes for semi-analytic models." Monthly Notices of the Royal Astronomical Society 510, no. 2 (December 3, 2021): 2900–2919. http://dx.doi.org/10.1093/mnras/stab3494.

Full text

Abstract:

ABSTRACT We present a model to track the orbital evolution of ‘unresolved subhaloes’ (USHs) in cosmological simulations. USHs are subhaloes that are no longer distinguished by halo finders as self-bound overdensities within their larger host system due to limited mass resolution. These subhaloes would host ‘orphan galaxies’ in semi-analytic models of galaxy formation and evolution (SAMs). Predicting the evolution of the phase-space components of USHs is crucial for the adequate modelling of environmental processes, interactions, and mergers implemented in SAMs that affect the baryonic properties of orphan satellites. Our model takes into account dynamical friction drag, mass-loss by tidal stripping and merger with the host halo, involving three free parameters. To calibrate this model, we consider two DM-only simulations of different mass resolution (MultiDark simulations). The simulation with higher mass resolution (smdpl; $m_{\rm DM} = 9.6 \times 10^7\, h^{-1}\, \mathrm{M_{\odot }}$) provides information about subhaloes that are not resolved in the lower mass resolution one (mdpl2; $m_{\rm DM} = 1.5 \times 10^9\, h^{-1}\, \mathrm{M_{\odot }}$); the orbit of those USHs is tracked by our model. We use as constraining functions the subhalo mass function (SHMF) and the two-point correlation function (2PCF) obtained from smdpl, being the latter a novel aspect of our approach. While the SHMF fails to put tight constraints on the efficiency of dynamical friction and the merger condition, the addition of clustering information helps us to specify the parameters of the model related to the spatial distribution of subhaloes. Our model allows to achieve good convergence between the results of simulations of different mass resolution, with a precision better than 10 per cent for both SHMF and 2PCF.

APA, Harvard, Vancouver, ISO, and other styles

7

Mitchell, Peter D., Cedric G. Lacey, Claudia D. P. Lagos, Carlos S. Frenk, Richard G. Bower, Shaun Cole, John C. Helly, Matthieu Schaller, Violeta Gonzalez-Perez, and Tom Theuns. "Comparing galaxy formation in semi-analytic models and hydrodynamical simulations." Monthly Notices of the Royal Astronomical Society 474, no. 1 (October 25, 2017): 492–521. http://dx.doi.org/10.1093/mnras/stx2770.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Yates, Robert M., Bruno Henriques, Peter A. Thomas, Guinevere Kauffmann, Jonas Johansson, and Simon D. M. White. "Modelling element abundances in semi-analytic models of galaxy formation." Monthly Notices of the Royal Astronomical Society 435, no. 4 (September 9, 2013): 3500–3520. http://dx.doi.org/10.1093/mnras/stt1542.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Henriques, Bruno M., Serena Bertone, and Peter A. Thomas. "The effect of dwarf galaxy disruption in semi-analytic models." Monthly Notices of the Royal Astronomical Society 383, no. 4 (December 21, 2007): 1649–54. http://dx.doi.org/10.1111/j.1365-2966.2007.12684.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Brennan, Ryan, Viraj Pandya, Rachel S. Somerville, Guillermo Barro, Edward N. Taylor, Stijn Wuyts, Eric F. Bell, et al. "Quenching and morphological transformation in semi-analytic models and CANDELS." Monthly Notices of the Royal Astronomical Society 451, no. 3 (June 17, 2015): 2933–56. http://dx.doi.org/10.1093/mnras/stv1007.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Fu, Jian. "Radial resolved galaxy disks models based on semi-analytic models of galaxy formation." Proceedings of the International Astronomical Union 15, S341 (November 2019): 273–74. http://dx.doi.org/10.1017/s1743921319002199.

Full text

Abstract:

AbstractWe show our work on the L-Galaxies semi-analytic models of galaxy formation, which includes the radial resolved distribution of star, gas, SFR and metallicity on each galaxy disk. The newest version of the codes include the H22-to-HI gas transition prescriptions and the chemical enrichment of various elements. Our revised model can give results on cold gas components, radial metallicity gradients and scaling relations, which can fit the recent observations.

APA, Harvard, Vancouver, ISO, and other styles

12

Wang, Lan, Gabriella De Lucia, Fabio Fontanot, and Michaela Hirschmann. "Starburst galaxies in semi-analytic models of galaxy formation and evolution." Monthly Notices of the Royal Astronomical Society 482, no. 4 (November 6, 2018): 4454–65. http://dx.doi.org/10.1093/mnras/sty2998.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Leung, Philip K. C., and Gordon I. Ogilvie. "Local semi-analytic models of magnetic flux transport in protoplanetary discs." Monthly Notices of the Royal Astronomical Society 487, no. 4 (June 11, 2019): 5155–74. http://dx.doi.org/10.1093/mnras/stz1620.

Full text

Abstract:

Abstract The evolution of a large-scale poloidal magnetic field in an accretion disc is an important problem because it determines the launching of winds and the feasibility of the magnetorotational instability to generate turbulence or channel flows. Recent studies, both semi-analytical calculations and numerical simulations, have highlighted the crucial role non-ideal magnetohydrodynamic effects (Ohmic resistivity, Hall drift, and ambipolar diffusion), relevant in the protoplanetary disc context, might play in magnetic flux evolution in the disc. We investigate the flux transport in discs through the use of two 1D semi-analytic models in the vertical direction, exploring regimes where different physical source terms and effects dominate. The governing equations for both models are derived by performing an asymptotic expansion in the limit of a thin disc, with the different regimes isolated through setting the relative order of the leading terms between variables. Flux transport rates and vertical structure profiles are calculated for a range of diffusivities and disc magnetizations. We found that Ohmic and ambipolar diffusivities drive radially outward flux transport with an outwardly inclined field. A wind outflow drives inward flux transport, which is significantly enhanced in the presence of Hall drift in the positive polarity case, $\eta _\mathrm{ H} (\boldsymbol{B}_\mathrm{ z} \cdot \boldsymbol{\Omega }) \gt 0$, an effect which has only been briefly noted before. Coupled only with outward inclination, the Hall effect reduces the flux transport given by a background Ohmic and/or ambipolar diffusivity, but drives no flux transport when it is the only non-ideal effect present.

APA, Harvard, Vancouver, ISO, and other styles

14

Snaith, Owain N., Brad K. Gibson, Chris B. Brook, Stéphanie Courty, Patricia Sánchez-Blázquez, Daisuke Kawata, Alexander Knebe, and Laura V. Sales. "A comparison of galaxy group luminosity functions from semi-analytic models." Monthly Notices of the Royal Astronomical Society 415, no. 3 (June 24, 2011): 2798–811. http://dx.doi.org/10.1111/j.1365-2966.2011.18907.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Hirschmann, Michaela, Thorsten Naab, Rachel S. Somerville, Andreas Burkert, and Ludwig Oser. "Galaxy formation in semi-analytic models and cosmological hydrodynamic zoom simulations." Monthly Notices of the Royal Astronomical Society 419, no. 4 (December 6, 2011): 3200–3222. http://dx.doi.org/10.1111/j.1365-2966.2011.19961.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Hou, Jun, Cedric G. Lacey, and Carlos S. Frenk. "A new gas cooling model for semi-analytic galaxy formation models." Monthly Notices of the Royal Astronomical Society 475, no. 1 (December 13, 2017): 543–69. http://dx.doi.org/10.1093/mnras/stx3218.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Berry, Michael, Rachel S. Somerville, Marcel R. Haas, Eric Gawiser, Ari Maller, Gergö Popping, and Scott C. Trager. "Damped Lyα absorption systems in semi-analytic models with multiphase gas." Monthly Notices of the Royal Astronomical Society 441, no. 2 (May 3, 2014): 939–63. http://dx.doi.org/10.1093/mnras/stu613.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Monaco, P., A. J. Benson, G. De Lucia, F. Fontanot, S. Borgani, and M. Boylan-Kolchin. "A semi-analytic model comparison: testing cooling models against hydrodynamical simulations." Monthly Notices of the Royal Astronomical Society 441, no. 3 (May 15, 2014): 2058–77. http://dx.doi.org/10.1093/mnras/stu655.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Somerville, Rachel S., Gergö Popping, and Scott C. Trager. "Star formation in semi-analytic galaxy formation models with multiphase gas." Monthly Notices of the Royal Astronomical Society 453, no. 4 (September 17, 2015): 4338–68. http://dx.doi.org/10.1093/mnras/stv1877.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Kim, Myungbae, Byungil Choi, and Taehoon Kim. "A new categorization of release models using a semi-analytic solution." Journal of Loss Prevention in the Process Industries 35 (May 2015): 80–84. http://dx.doi.org/10.1016/j.jlp.2015.03.019.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Hilder, Thomas, Daniele Fasano, Francesco Bollati, and Jacob Vandenberg. "Wakeflow: A Python package for semi-analytic models of planetary wakes." Journal of Open Source Software 8, no. 82 (February 28, 2023): 4863. http://dx.doi.org/10.21105/joss.04863.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Raouf, Mojtaba, Habib G. Khosroshahi, Gary A. Mamon, Darren J. Croton, Abdolhosein Hashemizadeh, and Ali A. Dariush. "Merger History of Central Galaxies in Semi-analytic Models of Galaxy Formation." Astrophysical Journal 863, no. 1 (August 8, 2018): 40. http://dx.doi.org/10.3847/1538-4357/aace57.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Takahashi, Takashi, and Yoshiyuki Kabashima. "Semi-analytic approximate stability selection for correlated data in generalized linear models." Journal of Statistical Mechanics: Theory and Experiment 2020, no. 9 (September 3, 2020): 093402. http://dx.doi.org/10.1088/1742-5468/ababff.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Triani, Dian, Darren Croton, and Manodeep Sinha. "Mentari: A pipeline to model the galaxy SED using semi analytic models." Proceedings of the International Astronomical Union 15, S341 (November 2019): 119–23. http://dx.doi.org/10.1017/s1743921319002813.

Full text

Abstract:

AbstractWe build a theoretical picture of how the light from galaxies evolves across cosmic time. In particular, we predict the evolution of the galaxy spectral energy distribution (SED) by carefully integrating the star formation and metal enrichment histories of semi-analytic model (SAM) galaxies and combining these with stellar population synthesis models which we call mentari. Our SAM combines prescriptions to model the interplay between gas accretion, star formation, feedback process, and chemical enrichment in galaxy evolution. From this, the SED of any simulated galaxy at any point in its history can be constructed and compared with telescope data to reverse engineer the various physical processes that may have led to a particular set of observations. The synthetic SEDs of millions of simulated galaxies from mentari can cover wavelengths from the far UV to infrared, and thus can tell a near complete story of the history of galaxy evolution.

APA, Harvard, Vancouver, ISO, and other styles

25

Yu-fei, Yang. "Application of Weighted Correlation Functions to Semi-analytic Models and SDSS Data." Chinese Astronomy and Astrophysics 34, no. 3 (July 2010): 255–64. http://dx.doi.org/10.1016/j.chinastron.2010.07.010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Saghiha, Hananeh, Patrick Simon, Peter Schneider, and Stefan Hilbert. "Confronting semi-analytic galaxy models with galaxy-matter correlations observed by CFHTLenS." Astronomy & Astrophysics 601 (May 2017): A98. http://dx.doi.org/10.1051/0004-6361/201629608.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Ruiz, Andrés N., Sofía A. Cora, Nelson D. Padilla, Mariano J. Domínguez, Cristian A. Vega Martínez, Tomás E. Tecce, Álvaro Orsi, et al. "CALIBRATION OF SEMI-ANALYTIC MODELS OF GALAXY FORMATION USING PARTICLE SWARM OPTIMIZATION." Astrophysical Journal 801, no. 2 (March 12, 2015): 139. http://dx.doi.org/10.1088/0004-637x/801/2/139.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Nakasato, N. "Origin of the galaxy morphology." Symposium - International Astronomical Union 208 (2003): 431–32. http://dx.doi.org/10.1017/s0074180900207614.

Full text

Abstract:

In the current most plausible Cold Dark Matter (CDM) cosmology, larger halos increase their mass by the progressive mergers of smaller clumps. Due to these progressive merger events, galaxies have formed and evolved. Such merger events could trigger star bursts depending on mass of a merging object. In other words, star formation history reflects the strength of the interaction between a galaxy and merging objects. Also, a several merger events strongly affect the development of the morphology of galaxies as assumed in semi-analytic models. In the most advanced semi-analytic models, N-body simulations of dark matter particles are used to obtain the merging history of halos. By combining the description of radiative cooling, hydrodynamics and star formation with the obtained merging history, such models successfully have explained the various qualitative predictions. Here, we show the results of similar approach but using a fullly numerical model. In contrast to the semi-analytic models, we use our high resolution Smoothed Particle Hydrodynamics (SPH) models. With our SPH code, we try to tackle the problem of the galaxy morphology. We have done a several handful high-resolution SPH simulations and analyzed the merging history of such models. Accordingly, we can see the relation between the obtained morphology and the merging history or other physical properties of the model.

APA, Harvard, Vancouver, ISO, and other styles

29

Côté, Benoit, Devin W. Silvia, Brian W. O’Shea, Britton Smith, and John H. Wise. "Validating Semi-analytic Models of High-redshift Galaxy Formation Using Radiation Hydrodynamical Simulations." Astrophysical Journal 859, no. 1 (May 24, 2018): 67. http://dx.doi.org/10.3847/1538-4357/aabe8f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Hou, Jun, Cedric G. Lacey, and Carlos S. Frenk. "How well is angular momentum accretion modelled in semi-analytic galaxy formation models?" Monthly Notices of the Royal Astronomical Society 507, no. 3 (August 28, 2021): 4241–61. http://dx.doi.org/10.1093/mnras/stab2454.

Full text

Abstract:

ABSTRACT Gas cooling and accretion in haloes delivers mass and angular momentum on to galaxies. In this work, we investigate the accuracy of the modelling of this important process in several different semi-analytic (SA) galaxy formation models (galform, l-galaxies, and morgana) through comparisons with a hydrodynamical simulation performed with the moving-mesh code arepo. Both SA models and the simulation were run without any feedback or metal enrichment, in order to focus on the cooling and accretion process. All of the SA models considered here assume that gas cools from a spherical halo. We found that the assumption that the gas conserves its angular momentum when moving from the virial radius, rvir, to the central region of the halo, r ∼ 0.1rvir, is approximately consistent with the results from our simulation. We also found that, compared to the simulation, the morgana model tends to overestimate the mean specific angular momentum of cooled-down gas, the l-galaxies model also tends to overestimate this in low-redshift massive haloes, while the two older galform models tend to underestimate the angular momentum. In general, the predictions of the new galform cooling model developed by Hou et al. agree the best with the simulation.

APA, Harvard, Vancouver, ISO, and other styles

31

Mutch, Simon J., Gregory B. Poole, and Darren J. Croton. "Constraining the last 7 billion years of galaxy evolution in semi-analytic models." Monthly Notices of the Royal Astronomical Society 428, no. 3 (November 5, 2012): 2001–16. http://dx.doi.org/10.1093/mnras/sts182.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Fu, Jian, Guinevere Kauffmann, Mei-ling Huang, Robert M. Yates, Sean Moran, Timothy M. Heckman, Romeel Davé, Qi Guo, and Bruno M. B. Henriques. "Star formation and metallicity gradients in semi-analytic models of disc galaxy formation." Monthly Notices of the Royal Astronomical Society 434, no. 2 (July 12, 2013): 1531–48. http://dx.doi.org/10.1093/mnras/stt1117.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Yang, Shengqi, Xiaolong Du, Andrew J. Benson, Anthony R. Pullen, and Annika H. G. Peter. "A new calibration method of sub-halo orbital evolution for semi-analytic models." Monthly Notices of the Royal Astronomical Society 498, no. 3 (September 23, 2020): 3902–13. http://dx.doi.org/10.1093/mnras/staa2496.

Full text

Abstract:

ABSTRACT Understanding the non-linear dynamics of satellite haloes (a.k.a. ‘sub-haloes’) is important for predicting the abundance and distribution of dark matter sub-structures and satellite galaxies, and for distinguishing among microphysical dark matter models using observations. Typically, modelling these dynamics requires large N-body simulations with high resolution. Semi-analytic models can provide a more efficient way to describe the key physical processes such as dynamical friction, tidal mass loss, and tidal heating, with only a few free parameters. In this work, we present a fast Markov chain Monte Carlo fitting approach to explore the parameter space of such a sub-halo non-linear evolution model. We use the dynamical models described in an earlier work and calibrate the models to two sets of high-resolution cold dark matter N-body simulations, ELVIS and Caterpillar. Compared to previous calibrations that used manual parameter tuning, our approach provides a more robust way to determine the best-fitting parameters and their posterior probabilities. We find that jointly fitting for the sub-halo mass and maximum velocity functions can break the degeneracy between tidal stripping and tidal heating parameters, as well as providing better constraints on the strength of dynamical friction. We show that our semi-analytic simulation can accurately reproduce N-body simulations statistics, and that the calibration results for the two sets of N-body simulations agree at 95 per cent confidence level. Dynamical models calibrated in this work will be important for future dark matter sub-structure studies.

APA, Harvard, Vancouver, ISO, and other styles

34

Henriques, Bruno M. B., Peter A. Thomas, Seb Oliver, and Isaac Roseboom. "Monte Carlo Markov Chain parameter estimation in semi-analytic models of galaxy formation." Monthly Notices of the Royal Astronomical Society 396, no. 1 (June 11, 2009): 535–47. http://dx.doi.org/10.1111/j.1365-2966.2009.14730.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Bertone, Serena, and Christopher J. Conselice. "A comparison of galaxy merger history observations and predictions from semi-analytic models." Monthly Notices of the Royal Astronomical Society 396, no. 4 (July 11, 2009): 2345–58. http://dx.doi.org/10.1111/j.1365-2966.2009.14916.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Fu, Jian, and Yu Luo. "The atomic gas in outer disks in semi-analytic models of galaxy formation." Proceedings of the International Astronomical Union 11, S321 (March 2016): 131. http://dx.doi.org/10.1017/s1743921316011017.

Full text

Abstract:

AbstractWe use semi-analytic models of galaxy formation L-Galaxies based on ΛCDM cosmology to study the HI gas component in galaxy outskirts. We adopt the radially-resolved version of the models by Fu et al. (2013), which includes both atomic and molecular gas component in interstellar medium. This model has been recently updated by Luo et al. (2016) to include cold gas stripping in the outer disk regions of the satellite galaxies by ram pressure. In our models, we can perfectly reproduce the HI size-mass relation, which is discovered by Broeils & Rhee (1997) and confirmed by many subsequent observations. In our model, the reason for such tight correlation between HI size and mass is atomic-molecular phase conversion in high gas surface density regions while HI ionization in low gas surface density region, which leads to very narrow distribution of HI mean surface density. The models also reproduce the universal exponential HI radial profiles in galaxy outskirts found by Bluedisk (Wang et al. 2013), which arises from cold gas accretion onto the galaxy disks in exponentially profiles.

APA, Harvard, Vancouver, ISO, and other styles

37

Fokker, Peter A., Francesca Verga, and Paul Egberts. "New Semi-Analytic Technique to Determine Horizontal Well PI in Fractured Reservoirs." SPE Reservoir Evaluation & Engineering 8, no. 02 (April 1, 2005): 123–31. http://dx.doi.org/10.2118/84597-pa.

Full text

Abstract:

Summary Simplified analytical relations derived for homogeneous formations are usually applied to the determination of the productivity of horizontal wells, regardless of the presence of heterogeneities in the reservoir. Furthermore, complex well architectures and the wealth of completion options currently available cannot be taken into account properly because the well trajectory can only be schematized as a single horizontal wellbore. However, the use of numerical reservoir simulators to reliably forecast the productivity of horizontal wells draining heterogeneous reservoirs may be time-prohibitive or not feasible because of a lack of sufficiently detailed information, especially during the appraisal phase or the early stages of production. A new semianalytic technique is proposed in this paper to solve the inflow equations in an approximate yet reliable manner. A solution to 3D problems of single-phase flow into a horizontal well, taking into account friction in the wellbore, is provided for both single-layer reservoirs and reservoirs comprising two interfering layers. The method also has been extended to describe the fluid flow when the well intercepts one or more fractures. The presented technique allows very fast calculation of the well productivity in oil and gas reservoirs, offering great flexibility in the placement and architecture of the wells. The method has been applied to two field cases for which the well productivity under pseudosteady-state conditions was measured. One of these is a 200-m-long horizontal well draining an isotropic carbonatic reservoir and intersected by a natural low-conductivity fracture. The other is a similar well, intercepting a natural high-conductivity fault, but the oil-bearing formation is anisotropic. Good correspondence was found between the actual productivity and the predictions obtained by application of the proposed semianalytic technique. Introduction Horizontal wells are common practice in the present hydrocarbon industry, and smart wells (including multilateral completions and wells with selective access of different zones) are becoming increasingly commonplace. The modeling of such wells is, in many cases, not ideal. Areas in which improvements are welcome are well testing, well models in reservoir simulators, and fast models for quick assessment of many field-development options. Further, the handling of natural or hydraulic fractures is often suboptimal. In reservoir simulation, fine grids need to be selected to properly capture the flow behavior close to the well. Moreover, most reservoir simulators are not equipped with extensive well models, which are required when friction in the well becomes important or when two-phase flow develops in the well. This situation has prompted the development of a number of analytical and semianalytical tools, some of which are intended for implementation in a reservoir simulator. Most of the first models, as well as many of the more recent models, assume either constant influx density along the well or infinite well conductivity in a single homogeneous layer. Dikken introduced the effect of well conductivity for a single horizontal well in a homogeneous formation. He started with the assumption that the flow is mainly perpendicular to the wellbore, which allowed him to reduce the reservoir to a 2D flow domain, coupled to a friction model in the well. Others followed this approach, but 3Dmodels were developed as well. A second kind of extension are the multilayer models. Lee and Milliken and Kuchuk and Habashy used a method of reflection and transmission, while Basquet et al. used a "quadrupole" method relating the pressures between the various layers. The multilayer models are also, however, still limited to constant-influx or infinite-conductivity wells.

APA, Harvard, Vancouver, ISO, and other styles

38

Yung, L. Y. Aaron, Rachel S. Somerville, Gergö Popping, and Steven L. Finkelstein. "Semi-analytic forecasts for JWST – III. Intrinsic production efficiency of Lyman-continuum radiation." Monthly Notices of the Royal Astronomical Society 494, no. 1 (March 14, 2020): 1002–17. http://dx.doi.org/10.1093/mnras/staa714.

Full text

Abstract:

ABSTRACT The James Webb Space Telescope is expected to enable transformational progress in studying galaxy populations in the very early Universe, during the epoch of reionization. A critical parameter for understanding the sources that reionized the Universe is the Lyman-continuum production efficiency, ξion, defined as the rate of production of ionizing photons divided by the intrinsic UV luminosity. In this work, we combine self-consistent star formation and chemical enrichment histories predicted by semi-analytic models of galaxy formation with stellar population synthesis (SPS) models to predict the expected dependence of ξion on galaxy properties and cosmic epoch from z = 4–10. We then explore the sensitivity of the production rate of ionizing photons, $\dot{N}_\text{ion}$, to the choice of SPS model and the treatment of stellar feedback in our galaxy formation model. We compare our results to those of other simulations, constraints from empirical models, and observations. We find that adopting SPS models that include binary stars predict about a factor of 2 more ionizing radiation than models that only assume single stellar populations. We find that UV-faint, low-mass galaxies have values of ξion about 0.25 dex higher than those of more massive galaxies, but find weak evolution with cosmic time, about 0.2 dex from z ∼ 12–4 at fixed rest-UV luminosity. We provide predictions of $\dot{N}_\text{ion}$ as a function of Mh and a number of other galaxy properties. All results presented in this work are available at https://www.simonsfoundation.org/semi-analytic-forecasts-for-jwst/.

APA, Harvard, Vancouver, ISO, and other styles

39

Comerford, Julia M., Eliot Quataert, and Chung-Pei Ma. "Constraints on Elliptical Galaxy Formation from Dry Mergers." Proceedings of the International Astronomical Union 2, S235 (August 2006): 195. http://dx.doi.org/10.1017/s1743921306006016.

Full text

Abstract:

Recent observations suggest that dissipationless mergers of elliptical galaxies build up the population of massive early-type galaxies (Bell et al. 2004; Faber et al. 2006). This type of merger is observed in galaxy clusters (Tran et al. 2005) and predicted by semi-analytic models which find mass assembly times significantly later than star-formation times for the most massive elliptical galaxies (de Lucia & Blaizot 2006). Here, we use a semi-analytic model of minor mergers of dark matter halos to examine the role of dry minor mergers in elliptical galaxy formation.

APA, Harvard, Vancouver, ISO, and other styles

40

Qiu, Yisheng, Simon J. Mutch, Pascal J. Elahi, Rhys J. J. Poulton, Chris Power, and J. Stuart B. Wyithe. "An efficient hybrid method to produce high-resolution large-volume dark matter simulations for semi-analytic models of reionization." Monthly Notices of the Royal Astronomical Society 500, no. 1 (October 22, 2020): 493–505. http://dx.doi.org/10.1093/mnras/staa3261.

Full text

Abstract:

ABSTRACT Resolving faint galaxies in large volumes is critical for accurate cosmic reionization simulations. While less demanding than hydrodynamical simulations, semi-analytic reionization models still require very large N-body simulations in order to resolve the atomic cooling limit across the whole reionization history within box sizes ${\gtrsim}100 \, h^{-1}\, \rm Mpc$. To facilitate this, we extend the mass resolution of N-body simulations using a Monte Carlo algorithm. We also propose a method to evolve positions of Monte Carlo haloes, which can be an input for semi-analytic reionization models. To illustrate, we present an extended halo catalogue that reaches a mass resolution of $M_\text{halo} = 3.2 \times 10^7 \, h^{-1} \, \text{M}_\odot$ in a $105 \, h^{-1}\, \rm Mpc$ box, equivalent to an N-body simulation with ∼68003 particles. The resulting halo mass function agrees with smaller volume N-body simulations with higher resolution. Our results also produce consistent two-point correlation functions with analytic halo bias predictions. The extended halo catalogues are applied to the meraxes semi-analytic reionization model, which improves the predictions on stellar mass functions, star formation rate densities, and volume-weighted neutral fractions. Comparison of high-resolution large-volume simulations with both small-volume and low-resolution simulations confirms that both low-resolution and small-volume simulations lead to reionization ending too rapidly. Lingering discrepancies between the star formation rate functions predicted with and without our extensions can be traced to the uncertain contribution of satellite galaxies.

APA, Harvard, Vancouver, ISO, and other styles

41

Fontanot, Fabio, Anna Pasquali, Gabriella De Lucia, Frank C. van den Bosch, Rachel S. Somerville, and Xi Kang. "The dependence of AGN activity on stellar and halo mass in semi-analytic models." Monthly Notices of the Royal Astronomical Society 413, no. 2 (February 16, 2011): 957–70. http://dx.doi.org/10.1111/j.1365-2966.2010.18186.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Lovell, Mark R., Sownak Bose, Alexey Boyarsky, Shaun Cole, Carlos S. Frenk, Violeta Gonzalez-Perez, Rachel Kennedy, Oleg Ruchayskiy, and Alex Smith. "Satellite galaxies in semi-analytic models of galaxy formation with sterile neutrino dark matter." Monthly Notices of the Royal Astronomical Society 461, no. 1 (June 7, 2016): 60–72. http://dx.doi.org/10.1093/mnras/stw1317.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Harker, Geraint, Shaun Cole, and Adrian Jenkins. "Constraints on σ8 from galaxy clustering in N-body simulations and semi-analytic models." Monthly Notices of the Royal Astronomical Society 382, no. 4 (December 7, 2007): 1503–15. http://dx.doi.org/10.1111/j.1365-2966.2007.12508.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Tao, Jiang, Chen Jian-Jun, and Xu Ya-Lan. "A semi-analytic method for calculating non-probabilistic reliability index based on interval models." Applied Mathematical Modelling 31, no. 7 (July 2007): 1362–70. http://dx.doi.org/10.1016/j.apm.2006.02.013.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Silva, Laura, Fabio Fontanot, and Gian Luigi Granato. "Fast radiative transfer of dust reprocessing in semi-analytic models with artificial neural networks." Monthly Notices of the Royal Astronomical Society 423, no. 1 (May 1, 2012): 746–55. http://dx.doi.org/10.1111/j.1365-2966.2012.20917.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Lu, Yu, Risa H. Wechsler, Rachel S. Somerville, Darren Croton, Lauren Porter, Joel Primack, Peter S. Behroozi, et al. "SEMI-ANALYTIC MODELS FOR THE CANDELS SURVEY: COMPARISON OF PREDICTIONS FOR INTRINSIC GALAXY PROPERTIES." Astrophysical Journal 795, no. 2 (October 21, 2014): 123. http://dx.doi.org/10.1088/0004-637x/795/2/123.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Maciel, Tamela, and Paul Alexander. "Radio source evolution from galaxy core to intracluster medium." Proceedings of the International Astronomical Union 10, S313 (September 2014): 271–76. http://dx.doi.org/10.1017/s1743921315002318.

Full text

Abstract:

AbstractThere is mounting evidence that mechanical kinetic-mode AGN feedback is important in galaxy evolution, and in order to quantify this feedback, detailed models of radio source evolution are required. Self-similar analytic models exist for large powerful radio sources but the evolution of young precursor radio sources is not yet fully understood. In this talk we present a versatile dynamical and radiative model for young source evolution on sub-kiloparsec scales, which extends existing self-similar models into a more complete radio source evolutionary model. This semi-analytic model is successful in reproducing the strong spectral aging observed in compact symmetric objects.

APA, Harvard, Vancouver, ISO, and other styles

48

Brennan, Sean, Andrew J. Benson, Francis-Yan Cyr-Racine, Charles R. Keeton, Leonidas A. Moustakas, and Anthony R. Pullen. "Quantifying the power spectrum of small-scale structure in semi-analytic galaxies." Monthly Notices of the Royal Astronomical Society 488, no. 4 (August 5, 2019): 5085–92. http://dx.doi.org/10.1093/mnras/stz1607.

Full text

Abstract:

Abstract In the cold dark matter (CDM) picture of structure formation, galaxy mass distributions are predicted to have a considerable amount of structure on small scales. Strong gravitational lensing has proven to be a useful tool for studying this small-scale structure. Much of the attention has been given to detecting individual dark matter subhaloes through lens modelling, but recent work has suggested that the full population of subhaloes could be probed using a power spectrum analysis. In this paper, we quantify the power spectrum of small-scale structure in simulated galaxies, with the goal of understanding theoretical predictions and setting the stage for using measurements of the power spectrum to test dark matter models. We use a sample of simulated galaxies generated from the galacticus semi-analytic model to determine the power spectrum distribution first in the CDM paradigm and then in a warm dark matter scenario. We find that a measurement of the slope and amplitude of the power spectrum on galaxy strong lensing scales (k ∼ 1 kpc−1) could be used to distinguish between CDM and alternate dark matter models, especially if the most massive subhaloes can be directly detected via gravitational imaging.

APA, Harvard, Vancouver, ISO, and other styles

49

Tonini, Chiara. "The hierarchical evolution of Brightest Cluster Galaxies: red galaxies in a young universe." Proceedings of the International Astronomical Union 8, S295 (August 2012): 200–203. http://dx.doi.org/10.1017/s174392131300478x.

Full text

Abstract:

AbstractWe investigate the evolution of Brightest Cluster Galaxies (BCGs) from redshift z ~ 1.6 to z = 0. We upgrade the hierarchical semi-analytic model of Croton et al. (2006) with a new spectro-photometric model that produces realistic galaxy spectra, making use of the Maraston (2005) stellar populations and a new recipe for the dust extinction. We compare the model predictions of the K-band luminosity evolution and the J-K, V-I and I-K colour evolution with a series of datasets, including Collins et al. (Nature, 2009) who argued that semi-analytic models based on the Millennium simulation cannot reproduce the red colours and high luminosity of BCGs at z > 1. We show instead that the model is well in range of the observed luminosity and correctly reproduces the colour evolution of BCGs in the whole redshift range up to z ~ 1.6. We argue that the success of the semi-analytic model is in large part due to the implementation of a more sophisticated spectro-photometric model. An analysis of the model BCGs shows an increase in mass by a factor 2-3 since z ~ 1, and star formation activity down to low redshifts. While the consensus regarding BCGs is that they are passively evolving, we argue that this conclusion is affected by the degeneracy between star formation history and stellar population models used in SED-fitting, and by the inefficacy of toy-models of passive evolution to capture the complexity of real galaxies, especially those with rich merger histories like BCGs. Following this argument, we also show that in the semi-analytic model, the BCGs show a realistic mix of stellar populations, and that these stellar populations are mostly old. In addition, the age-redshift relation of the model BCGs follows that of the Universe, meaning that given their merger history and star formation history, the ageing of BCGs is always dominated by the ageing of their stellar populations. In a ΛCDM Universe, we define such evolution as ‘passive in the hierarchical sense’.

APA, Harvard, Vancouver, ISO, and other styles

50

Fu, Jian. "HI gas component in dwarf and disk galaxies in the view of semi-analytic models." Proceedings of the International Astronomical Union 14, S344 (August 2018): 274–75. http://dx.doi.org/10.1017/s1743921318005823.

Full text

Abstract:

AbstractWe show our recent progress on the L-Galaxies semi-analytic models of galaxy formation, which focuses on the HI gas in low mass galaxies. We find that the model based on ELUCID haloes can reproduce the HI mass function from ALFALFA 100 at low mass end. On the other hand, our models predict some gas rich low mass galaxies around the Milky Way, which may offer opportunities for future HI 21cm survey in nearby universe by FAST and SKA-1.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!