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1. Can the Symmetric Fermi and eROSITA Bubbles Be Produced by Tilted Jets?

Author

Po-Hsun Tseng, H.-Y. Karen Yang, Chun-Yen Chen, Hsi-Yu Schive, and Tzihong Chiueh

Subjects
Galaxy jets, Relativistic jets, Galactic cosmic rays, Astrophysics, QB460-466
Abstract

The Fermi Gamma-Ray Space Telescope reveals two large bubbles in the Galaxy, extending nearly symmetrically ∼50° above and below the Galactic center (GC). Previous simulations of bubble formation invoking active galactic nucleus (AGN) jets have assumed that the jets are vertical to the Galactic disk; however, in general, the jet orientation does not necessarily correlate with the rotational axis of the Galactic disk. Using three-dimensional special relativistic hydrodynamic simulations including cosmic rays (CRs) and thermal gas, we show that the dense clumpy gas within the Galactic disk disrupts jet collimation (“failed jets” hereafter), which causes the failed jets to form hot bubbles. Subsequent buoyancy in the stratified atmosphere renders them vertical to form the symmetric Fermi and eROSITA bubbles (collectively, Galactic bubbles). We find that (1) despite the relativistic jets emanating from the GC at various angles ≤45° with respect to the rotational axis of the Galaxy, the Galactic bubbles nonetheless appear aligned with the axis; (2) the edge of the eROSITA bubbles corresponds to a forward shock driven by the hot bubbles; (3) followed by the forward shock is a tangling contact discontinuity corresponding to the edge of the Fermi bubbles; (4) assuming a leptonic model we find that the observed gamma-ray bubbles and microwave haze can be reproduced with a best-fit CR power-law spectral index of 2.4; The agreements between the simulated and the observed multiwavelength features suggest that forming the Galactic bubbles by oblique AGN failed jets is a plausible scenario.

Published
2024
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2. On the Dynamical Heating of Dwarf Galaxies in a Fuzzy Dark Matter Halo

Author

Dhruba Dutta Chowdhury, Frank C. van den Bosch, Pieter van Dokkum, Victor H. Robles, Hsi-Yu Schive, and Tzihong Chiueh

Subjects
Galaxy dynamics, Galaxy dark matter halos, Gravitational interaction, Astrophysics, QB460-466
Abstract

Fuzzy dark matter (FDM), consisting of ultralight bosons, is an intriguing alternative to cold dark matter. Numerical simulations solving the Schrödinger–Poisson (SP) equation, which governs FDM dynamics, show that FDM halos consist of a central solitonic core (representing the ground state of the SP equation), surrounded by a large envelope of excited states. Wave interference gives rise to density fluctuations of order unity throughout the envelope and causes the soliton to undergo density oscillations and execute a confined random walk in the central region of the halo. The resulting gravitational potential perturbations are an efficient source of dynamical heating. Using high-resolution numerical simulations of a 6.6 × 10 ^9 M _⊙ FDM halo with boson mass m _b = 8 × 10 ^−23 eV, we investigate the impact of this dynamical heating on the structure and kinematics of spheroidal dwarf galaxies of a fixed mass but different initial sizes and ellipticities. The galaxies are set up in equilibrium in the time-and-azimuthally averaged halo potential and evolved for 10 Gyr in the live FDM halo. We find that they continuously increase their sizes and central velocity dispersions. In addition, their kinematic structures become strongly radially anisotropic, especially in the outskirts. Dynamical heating also causes initially ellipsoidal galaxies to become more spherical over time from the inside out and gives rise to distorted, nonconcentric isodensity contours. These telltale characteristics of dynamical heating of dwarf galaxies in FDM halos can potentially be used to constrain the boson mass.

Published
2023
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3. Ultra Light Axionic Dark Matter: Galactic Halos and Implications for Observations with Pulsar Timing Arrays

Author

Ivan de Martino, Tom Broadhurst, S.-H. Henry Tye, Tzihong Chiueh, Hsi-Yu Schive, and Ruth Lazkoz

Subjects
dark matter, axions, particle physics, general relativity, pulsars, SKA, Astronomy, QB1-991
Abstract

The cold dark matter (CDM) paradigm successfully explains the cosmic structure over an enormous span of redshifts. However, it fails when probing the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. Moreover, the lack of experimental detection of Weakly Interacting Massive Particle (WIMP) favors alternative candidates such as light axionic dark matter that naturally arise in string theory. Cosmological N-body simulations have shown that axionic dark matter forms a solitonic core of size of ≃150 pc in the innermost region of the galactic halos. The oscillating scalar field associated to the axionic dark matter halo produces an oscillating gravitational potential that induces a time dilation of the pulse arrival time of ≃400 ns/(m B /10 − 22 eV) for pulsar within such a solitonic core. Over the whole galaxy, the averaged predicted signal may be detectable with current and forthcoming pulsar timing array telescopes.

Published
2018
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4. Galactic disc heating by density granulation in fuzzy dark matter simulations.

Author

Yang, Hsun-Yeong, Chiang, Barry T, Su, Guan-Ming, (薛熙于), Hsi-Yu Schive, (闕志鴻), Tzihong Chiueh, and Ostriker, Jeremiah P

Subjects
DARK matter, GRANULATION, QUANTUM interference, FUZZY neural networks, DENSITY, AXIONS, GALACTIC halos, SOLAR photosphere
Abstract

Fuzzy dark matter (FDM), an attractive dark matter candidate comprising ultralight bosons (axions) with a particle mass ma ∼ 10−22 eV, is motivated by the small-scale challenges of cold dark matter and features a kpc-size de Broglie wavelength. Quantum wave interference inside an FDM halo gives rise to stochastically fluctuating density granulation; the resulting gravitational perturbations could drive significant disc thickening, providing a natural explanation for galactic thick discs. Here we present the first self-consistent simulations of FDM haloes and stellar discs, exploring ma  = 0.2–1.2 × 10−22 eV and halo masses M h = 0.7–2.8 × 1011 M⊙. Disc thickening is observed in all simulated systems. The disc heating rates are approximately constant in time and increase substantially with decreasing ma , reaching d h /d t ≃ 0.04 (0.4) kpc Gyr−1 and |${\rm d}\sigma _z^2/{\rm d}t \simeq 4$| (150) km2 s−2 Gyr−1 for ma  = 1.2 (0.2) × 10−22 eV and |$M_{\rm h}=7\times 10^{10} \, \rm {M}_{\odot }$|⁠ , where h is the disc scale height and σ z is the vertical velocity dispersion. These simulated heating rates agree within a factor of two with the theoretical estimates of Chiang et al. confirming that the rough estimate of Church et al. overpredicts the granulation-driven disc heating rate by two orders of magnitude. However, the simulation-inferred heating rates scale less steeply than the theoretically predicted relation |${\rm d}\sigma ^2_z/{\rm d}t \propto m_a^{-3}$|⁠. Finally, we examine the applicability of the Fokker–Planck approximation in FDM granulation modelling and the robustness of the ma exclusion bound derived from the Galactic disc kinematics. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Cosmological simulations of two-component wave dark matter.

Author

(黃新豪), Hsinhao Huang, (薛熙于), Hsi-Yu Schive, and (闕志鴻), Tzihong Chiueh

Subjects
DARK matter, DE-Broglie waves, GALAXY formation, GRAVITY, GRAVITATIONAL potential, SOLITONS, BOSONS, GALACTIC halos
Abstract

Wave (fuzzy) dark matter (⁠|$\psi \rm {DM}$|⁠) consists of ultralight bosons, featuring a solitonic core within a granular halo. Here we extend |$\psi \rm {DM}$| to two components, with distinct particle masses m and coupled only through gravity, and investigate the resulting soliton–halo structure via cosmological simulations. Specifically, we assume |$\psi \rm {DM}$| contains 75 per cent major component and 25 per cent minor component, fix the major-component particle mass to |$m_{\rm major}=1\times 10^{-22}\, \rm eV$|⁠ , and explore two different minor-component particle masses with m major: m minor = 3: 1 and 1: 3, respectively. For m major: m minor = 3: 1, we find that (i) the major- and minor-component solitons coexist, have comparable masses, and are roughly concentric. (ii) The soliton peak density is significantly lower than the single-component counterpart, leading to a smoother soliton-to-halo transition and rotation curve. (iii) The combined soliton mass of both components follows the same single-component core–halo mass relation. In dramatic contrast, for m major: m minor = 1: 3, a minor-component soliton cannot form with the presence of a stable major-component soliton; the total density profile, for both halo and soliton, is thus dominated by the major component and closely follows the single-component case. To support this finding, we propose a toy model illustrating that it is difficult to form a soliton in a hot environment associated with a deep gravitational potential. The work demonstrates that the extra flexibility added to the multi-component |$\psi \rm {DM}$| model can resolve observational tensions over the single-component model while retaining its key features. [ABSTRACT FROM AUTHOR]

Published
2023
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6. On the Random Motion of Nuclear Objects in a Fuzzy Dark Matter Halo

Author

Frank C. van den Bosch, Dhruba Dutta Chowdhury, Tzihong Chiueh, Tom Broadhurst, Hsi-Yu Schive, Victor H. Robles, and Pieter G. van Dokkum

Subjects
Physics, Cold dark matter, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Gravitation, Dark matter halo, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Center of mass, Halo, Soliton, Astrophysics::Galaxy Astrophysics
Abstract

Fuzzy Dark Matter (FDM), consisting of ultralight bosons ($m_{\rm b} \sim 10^{-22}\ \rm eV$), is an intriguing alternative to Cold Dark Matter. Numerical simulations that solve the Schr\"odinger-Poisson (SP) equation show that FDM halos consist of a central solitonic core, which is the ground state of the SP equation, surrounded by an envelope of interfering excited states. These excited states also interfere with the soliton, causing it to oscillate and execute a confined random walk with respect to the halo center of mass. Using high-resolution numerical simulations of a $6.6 \times 10^9 M_{\odot}$ FDM halo with $m_{\rm b} = 8 \times 10^{-23}\ \rm eV$ in isolation, we demonstrate that the wobbling, oscillating soliton gravitationally perturbs nuclear objects, such as supermassive black holes or dense star clusters, causing them to diffuse outwards. In particular, we show that, on average, objects with mass $\lesssim 0.3 \%$ of the soliton mass ($M_{\rm sol}$) are expelled from the soliton in $\sim 3\ \rm Gyr$, after which they continue their outward diffusion due to gravitational interactions with the soliton and the halo granules. More massive objects ($\gtrsim 1 \% M_{\rm sol}$), while executing a random walk, remain largely confined to the soliton due to dynamical friction. We also present an effective treatment of the diffusion, based on kinetic theory, that accurately reproduces the outward motion of low mass objects and briefly discuss how the observed displacements of star clusters and active galactic nuclei from the centers of their host galaxies can be used to constrain FDM., Comment: 20 pages, 9 figures, minor revisions, accepted for publication in ApJ

Published
2021

7. Testing extreme-axion wave dark matter using the BOSS Lyman-Alpha forest data

Author

Tzihong Chiueh, Ka-Hou Leong, Hsi-Yu Schive, and Ui-Han Zhang

Subjects
Physics, Cold dark matter, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010308 nuclear & particles physics, Matter power spectrum, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Lyman-alpha forest, 01 natural sciences, Galaxy, Spectral line, Space and Planetary Science, 0103 physical sciences, 010303 astronomy & astrophysics, Axion, Boson, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Using cosmological particle hydrodynamical simulations and uniform ultraviolet backgrounds, we compare Lyman-$\alpha$ forest flux spectra predicted by the conventional cold dark matter (CDM) model, the free-particle wave dark matter (FP$\psi$DM) model and extreme-axion wave dark matter (EA$\psi$DM) models of different initial axion field angles against the BOSS Lyman-$\alpha$ forest absorption spectra with a fixed boson mass $m_b\sim 10^{-22}$eV. We recover results reported previously (Ir\v{s}i\v{c} et al. 2017b; Armengaud et al. 2017) that the CDM model agrees better with the BOSS data than the FP$\psi$DM model by a large margin, and we find the difference of total $\chi^2$'s is $120$ for $420$ data bins. These previous results demand a larger boson mass by a factor $>10$ to be consistent with the date and are in tension with the favoured value determined from local satellite galaxies. We however find that such tension is removed as some EA$\psi$DM models predict Lyman-$\alpha$ flux spectra agreeing better with the BOSS data than the CDM model, and the difference of total $\chi^2$'s can be as large as $24$ for the same bin number. This finding arises with no surprise since EA$\psi$DM models have unique spectral shapes with spectral bumps in excess of the CDM power near the small-scale cutoff typical of $\psi$DM linear matter power spectra as well as more extended cutoffs than FP$\psi$DM (Zhang & Chiueh 2017a,b).

Published
2018

8. Magnification Bias of Distant Galaxies in the Hubble Frontier Fields: Testing Wave vs. Particle Dark Matter Predictions

Author

Tzihong Chiueh, Enoch Leung, Rogier A. Windhorst, Hsi-Yu Schive, Tom Broadhurst, Jose M. Diego, and Jeremy Lim

Subjects
Physics, Cold dark matter, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Luminosity, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, Reionization, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Luminosity function (astronomy), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Acting as powerful gravitational lenses, the strong lensing galaxy clusters of the deep Hubble Frontier Fields (HFF) program permit access to lower-luminosity galaxies lying at higher redshifts than hitherto possible. We analyzed the HFF to measure the volume density of Lyman-break galaxies at $z > 4.75$ by identifying a complete and reliable sample up to $z \simeq 10$. A marked deficit of such galaxies was uncovered in the highly magnified regions of the clusters relative to their outskirts, implying that the magnification of the sky area dominates over additional faint galaxies magnified above the flux limit. This negative magnification bias is consistent with a slow rollover at the faint end of the UV luminosity function, and indicates a preference for Bose-Einstein condensate dark matter with a light boson mass of $m_\mathrm{B} \simeq 10^{-22} \, \mathrm{eV}$ over standard cold dark matter. We emphasize that measuring the magnification bias requires no correction for multiply lensed images (with typically three or more images per source), whereas directly reconstructing the luminosity function will lead to an overestimate unless such images can be exhaustively matched up, especially at the faint end that is accessible only in the strongly lensed regions. In addition, we detected a distinctive downward transition in galaxy number density at $z \gtrsim 8$, which may be linked to the relatively late reionization reported by Planck. Our results suggests that JWST will likely peer into an "abyss" with essentially no galaxies detected in deep NIR imaging at $z > 10$., 46 pages, 23 figures, accepted for publication in ApJ

Published
2018

9. Ultra Light Axionic Dark Matter: Galactic Halos and Implications for Observations with Pulsar Timing Arrays

Author

Tom Broadhurst, Tzihong Chiueh, Ruth Lazkoz, Ivan De Martino, S.-H. Henry Tye, and Hsi-Yu Schive

Subjects
Cold dark matter, axions, lcsh:Astronomy, Milky Way, Dark matter, CDM, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, wave, 01 natural sciences, dark matter, lcsh:QB1-991, Galactic halo, scale, Pulsar, 0103 physical sciences, general relativity, particle physics, 010306 general physics, invisible axion, Axion, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, SKA, Astronomy and Astrophysics, field, pulsars, Galaxy, Dark matter halo, modulation, onstraining F(R) gravity, cosmology
Abstract

The cold dark matter (CDM) paradigm successfully explains the cosmic structure over an enormous span of redshifts. However, it fails when probing the innermost regions of dark matter halos and the properties of the Milky Way’s dwarf galaxy satellites. Moreover, the lack of experimental detection of Weakly Interacting Massive Particle (WIMP) favors alternative candidates such as light axionic dark matter that naturally arise in string theory. Cosmological N-body simulations have shown that axionic dark matter forms a solitonic core of size of ≃150 pc in the innermost region of the galactic halos. The oscillating scalar field associated to the axionic dark matter halo produces an oscillating gravitational potential that induces a time dilation of the pulse arrival time of ≃400 ns/(m B /10 −22 eV) for pulsar within such a solitonic core. Over the whole galaxy, the averaged predicted signal may be detectable with current and forthcoming pulsar timing array telescopes. IDM acknowledges financial support from University of the Basque Country UPV/EHU under the program "Convocatoria de contratacion para la especializacion de personal investigador doctor en la UPV/EHU 2015", from the Spanish Ministerio de Economia y Competitividad through research project FIS2010-15492, and from the Basque Government through research project IT-956-16. RL is supported by the Spanish Ministry of Economy and Competitiveness through research projects FIS2010-15492 and Consolider EPI CSD2010-00064, and by the University of the Basque Country UPV/EHU under program UFI 11/55. IDM and RL also acknowledge support from the COST Action CA1511 Cosmology and Astrophysics Network for Theoretical Advances and Training Actions (CANTATA). TJB acknowledges generous hospitality from the Institute for Advanced Studies in Hong Kong and helpful conversations with Nick Kaiser and Kfir Blum. SHHT is supported by CRF Grant HKUST4/CRF/13G and GRF 16305414 issued by the Research Grants Council (RGC) of the Government of the Hong Kong SAR. Chipbond Technology Corporation is acknowledged for donating the GPU cluster with which this work was conducted. This work was supported in part by the National Science Council of Taiwan under grants NSC100-2112-M-002-018-MY3 and NSC99-2112-M-002-009-MY3

Published
2018
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10. Recognising Axionic Dark Matter by Compton and de-Broglie Scale Modulation of Pulsar Timing

Author

S.-H. Henry Tye, Tzihong Chiueh, Ruth Lazkoz, Hsi-Yu Schive, Ivan De Martino, and Tom Broadhurst

Subjects
Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010308 nuclear & particles physics, Hot dark matter, Dark matter, Scalar field dark matter, General Physics and Astronomy, FOS: Physical sciences, Computer Science::Computation and Language (Computational Linguistics and Natural Language and Speech Processing), Astrophysics, General Relativity and Quantum Cosmology (gr-qc), Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, General Relativity and Quantum Cosmology, Dark matter halo, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Galaxy formation and evolution, 010303 astronomy & astrophysics, Light dark matter, Axion, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Light Axionic Dark Matter, motivated by string theory, is increasingly favored for the "no-WIMP era". Galaxy formation is suppressed below a Jeans scale, of $\simeq 10^8 M_\odot$ by setting the axion mass to, $m_B \sim 10^{-22}$eV, and the large dark cores of dwarf galaxies are explained as solitons on the de-Broglie scale. This is persuasive, but detection of the inherent scalar field oscillation at the Compton frequency, $\omega_B= (2.5{\rm \, months})^{-1}(m_B/10^{-22}eV)$, would be definitive. By evolving the coupled Schr\"odinger-Poisson equation for a Bose-Einstein condensate, we predict the dark matter is fully modulated by de-Broglie interference, with a dense soliton core of size $\simeq 150pc$, at the Galactic center. The oscillating field pressure induces General Relativistic time dilation in proportion to the local dark matter density and pulsars within this dense core have detectably large timing residuals, of $\simeq 400nsec/(m_B/10^{-22}eV)$. This is encouraging as many new pulsars should be discovered near the Galactic center with planned radio surveys. More generally, over the whole Galaxy, differences in dark matter density between pairs of pulsars imprints a pairwise Galactocentric signature that can be distinguished from an isotropic gravitational wave background., Comment: 6 pages, 3 figures. Accepted for publication in Physics Review Letter

Published
2017

11. Cosmological Perturbations of Extreme Axion in the Radiation Era

Author

Ui-Han Zhang and Tzihong Chiueh

Subjects
Physics, Particle physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Cold dark matter, 010308 nuclear & particles physics, Oscillation, media_common.quotation_subject, FOS: Physical sciences, 01 natural sciences, Galaxy, Universe, 0103 physical sciences, Initial value problem, Boundary value problem, 010303 astronomy & astrophysics, Scalar field, Axion, media_common, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

Sub-horizon perturbations under the extreme initial condition of the axion model are investigated, where initial axion angles start near the potential maximum. This work focuses on a few new features found in the extreme axion model but absent in the free-particle model. A particularly novel new feature is the spectral excess relative to the CDM model in some wave number range, where the excess may be so large that landscapes of high-redshift universe beyond $z=10$ can be significantly altered. For axions of particle mass $10^{-22}$ eV, this range of wave number corresponds to first galaxies of few times $10^9-10^{10} M_\odot$. We demonstrate that sub-horizon perturbations are accurately described by Mathieu's equation and subject to parametric instability, which explains this novel feature. Actually the axion model is not a special one; perturbations in a wide range of scalar field models can share the similar characteristic., 11 pages, 3 figures

Published
2017

12. Hydrodynamical simulations of colliding jets:modeling 3C 75

Author

Sandor M. Molnar, Andrew J. Young, Tzihong Chiueh, Gibwa Musoke, Hsi-Yu Schive, and Mark Birkinshaw

Subjects
Physics, Jet (fluid), Break-Up, clusters: individual (Abell 400) [galaxies], Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, numerical [methods], Astrophysics, Collision, 01 natural sciences, Helicity, Galaxy, Projection (linear algebra), 010305 fluids & plasmas, Dumbbell shaped, extragalactic jets, Space and Planetary Science, clusters: intracluster medium [– galaxies], 0103 physical sciences, clusters: general [galaxies], High Energy Physics::Experiment, Impact parameter, 010303 astronomy & astrophysics
Abstract

Radio observations suggest that 3C 75, located in the dumbbell shaped galaxy NGC 1128 at the center of Abell 400, hosts two colliding jets. Motivated by this source, we perform three-dimensional hydrodynamical simulations using a modified version of the GPU-accelerated Adaptive-MEsh-Refinement hydrodynamical parallel code ($\mathit{GAMER}$) to study colliding extragalactic jets. We find that colliding jets can be cast into two categories: 1) bouncing jets, in which case the jets bounce off each other keeping their identities, and 2) merging jets, when only one jet emerges from the collision. Under some conditions the interaction causes the jets to break up into oscillating filaments of opposite helicity, with consequences for their downstream stability. When one jet is significantly faster than the other and the impact parameter is small, the jets merge; the faster jet takes over the slower one. In the case of merging jets, the oscillations of the filaments, in projection, may show a feature which resembles a double helix, similar to the radio image of 3C 75. Thus we interpret the morphology of 3C 75 as a consequence of the collision of two jets with distinctly different speeds at a small impact parameter, with the faster jet breaking up into two oscillating filaments.

Published
2017
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13. Galaxy-scale gravitational lens candidates from the Hyper Suprime-Cam imaging survey and the Galaxy And Mass Assembly spectroscopic survey

Author

Bau-Ching Hsieh, Anupreeta More, Hitoshi Murayama, Sherry H. Suyu, Tsuyoshi Terai, Paul A. Price, Masamune Oguri, Jean Coupon, Atsushi J. Nishizawa, Philip J. Tait, Yousuke Utsumi, Satoshi Miyazaki, Shiang-Yu Wang, Tzihong Chiueh, Yutaka Komiyama, and James H. H. Chan

Subjects
Physics, Initial mass function, Stellar population, Stellar mass, 010308 nuclear & particles physics, Dark matter, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Galaxy, Einstein radius, Gravitational lens, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Mass fraction, Astrophysics::Galaxy Astrophysics
Abstract

We present a list of galaxy-scale lens candidates including a highly probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC) imaging survey. We combine HSC imaging with the blended-spectra catalog from the Galaxy And Mass Assembly (GAMA) survey to identify lens candidates, and use lens mass modeling to confirm the candidates. We find 46 matches between the HSC S14A_0b imaging data release and the GAMA catalog. Ten of them are probable lens systems according to their morphology and redshifts. There is one system with an interacting galaxy pair, HSC J084928+000949, that has a valid mass model. We predict the total mass enclosed by the Einstein radius of $\sim0.72$" ($\sim1.65$kpc) for this new expected lens system to be $\sim10^{10.59}M_{\odot}$. Using the photometry in the {\it grizy} bands of the HSC survey and stellar population synthesis modeling with a Salpeter stellar initial mass function, we estimate the stellar mass within the Einstein radius to be $\sim10^{10.46}\,M_{\odot}$. We thus find a dark matter mass fraction within the Einstein radius of $\sim25\%$. Further spectroscopy or high-resolution imaging would allow confirmation of the nature of these lens candidates. The particular system with the interacting galaxy pair, if confirmed, would provide an opportunity to study the interplay between dark matter and stars as galaxies build up through hierarchical mergers., 10 pages, 5 figures

Published
2016

14. Sound-Triggered Collapse of Stably Oscillating Low-Mass Cores in a Two-Phase Interstellar Medium

Author

Ui-Han Zhang, Hsi-Yu Schive, and Tzihong Chiueh

Subjects
Coalescence (physics), Mass flux, Physics, Bok globule, Oscillation, Star formation, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Mechanics, Interstellar medium, symbols.namesake, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Adiabatic process, Bonnor–Ebert mass, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Inspired by Barnard 68, a Bok globule, that undergoes stable oscillations, we perform multi-phase hydrodynamic simulations to analyze the stability of Bok globules. We show that a high-density soft molecular core, with an adiabatic index $\gamma$ = 0.7 embedded in a warm isothermal diffuse gas, must have a small density gradient to retain the stability. Despite being stable, the molecular core can still collapse spontaneously as it will relax to develop a sufficiently large density gradient after tens of oscillations, or a few $10^7$ years. However, during its relaxation, the core may abruptly collapse triggered by the impingement of small-amplitude, long-wavelength ($\sim$ 6 $-$ 36 pc) sound waves in the warm gas. This triggered collapse mechanism is similar to a sonoluminescence phenomenon, where underwater ultrasounds can drive air bubble coalescence. The collapse configuration is found to be different from both inside-out and outside-in models of low-mass star formation; nonetheless the mass flux is close to the prediction of the inside-out model. The condition and the efficiency for this core collapse mechanism are identified. Generally speaking, a broad-band resonance condition must be met, where the core oscillation frequency and the wave frequency should match each other within a factor of several. A consequence of our findings predicts the possibility of propagating low-mass star formation, for which collapse of cores, within a mass range short of one order of magnitude, takes place sequentially tracing the wave front across a region of few tens of pc over $10^7$ years., Comment: 9 pages, 8 figures

Published
2015

15. Understanding the Core-Halo Relation of Quantum Wave Dark Matter, $\psi$DM, from 3D Simulations

Author

W-Y. Pauchy Hwang, Tom Broadhurst, Hsi-Yu Schive, Shing-Kwong Wong, Ming-Hsuan Liao, Tzihong Chiueh, and Tak-Pong Woo

Subjects
Physics, Structure formation, Cold dark matter, Dark matter, Center (category theory), General Physics and Astronomy, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Navarro–Frenk–White profile, Halo, Astrophysics::Galaxy Astrophysics, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We examine the nonlinear structure of gravitationally collapsed objects that form in our simulations of wavelike cold dark matter ($\psi$DM), described by the Schr\"{o}dinger-Poisson (SP) equation with a particle mass $\sim 10^{-22} {\rm eV}$. A distinct gravitationally self-bound solitonic core is found at the center of every halo, with a profile quite different from cores modeled in the warm or self-interacting dark matter scenarios. Furthermore, we show that each solitonic core is surrounded by an extended halo composed of large fluctuating dark matter granules which modulate the halo density on a scale comparable to the diameter of the solitonic core. The scaling symmetry of the SP equation and the uncertainty principle tightly relate the core mass to the halo specific energy, which, in the context of cosmological structure formation, leads to a simple scaling between core mass ($M_c$) and halo mass ($M_h$), $M_c \propto a^{-1/2} M_h^{1/3}$, where $a$ is the cosmic scale factor. We verify this scaling relation by (i) examining the internal structure of a statistical sample of virialized halos that form in our 3D cosmological simulations, and by (ii) merging multiple solitons to create individual virialized objects. Sufficient simulation resolution is achieved by adaptive mesh refinement and graphic processing units acceleration. From this scaling relation, present dwarf satellite galaxies are predicted to have kpc sized cores and a minimum mass of $\sim 10^8 {M_\odot}$, capable of solving the small-scale controversies in the cold dark matter model. Moreover, galaxies of $2\times10^{12} {M_\odot}$ at $z=8$ should have massive solitonic cores of $\sim 2\times10^9 {M_\odot}$ within $\sim 60 {\rm pc}$. Such cores can provide a favorable local environment for funneling the gas that leads to the prompt formation of early stellar spheroids and quasars., Comment: 6 pages, 4 figures, accepted for publication in PRL

Published
2014

16. Probability Friends-of-Friends (PFOF) Group Finder: Performance Study and Observational Data Applications on Photometric Surveys

Author

Nick Kaiser, Lihwai Lin, Sebastien Foucaud, Hung-Yu Jian, Chin-Wei Chen, William S. Burgett, Jiasheng Huang, David Murphy, Tzihong Chiueh, Alex Merson, Carlton M. Baugh, Shaun Cole, Kai-Yang Lin, and Hauyu Baobab Liu

Subjects
Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Group (mathematics), business.industry, Large-scale structure of universe, data analysis. [Methods], FOS: Physical sciences, Astronomy and Astrophysics, Pattern recognition, clusters: general [Galaxies], Astrophysics - Astrophysics of Galaxies, Galaxy, groups: general [Galaxies], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Range (statistics), Galaxy formation and evolution, Observational study, Artificial intelligence, business, Galaxy cluster, Reliability (statistics), Astrophysics - Cosmology and Nongalactic Astrophysics, Photometric redshift
Abstract

(Abridged) In tandem with observational datasets, we utilize realistic mock catalogs, based on a semi-analytic galaxy formation model, constructed specifically for Pan-STARRS1 Medium Deep Surveys in order to assess the performance of the Probability Friends-of-Friends (PFOF, Liu et al.) group finder, and aim to develop a grouping optimization method applicable to surveys like Pan-STARRS1. Producing mock PFOF group catalogs under a variety of photometric redshift accuracies ({\sigma}{\Delta}z/(1+zs)), we find that catalog purities and completenesses from ``good' {\sigma}{\Delta}z/(1+zs)) ~ 0.01) to ``poor' {\sigma}{\Delta}z/(1+zs)) ~ 0.07) photo-zs gradually degrade respectively from 77% and 70% to 52% and 47%. To avoid model dependency of the mock for use on observational data we apply a ``subset optimization' approach, using spectroscopic-redshift group data from the target field to train the group finder for application to that field, as an alternative method for the grouping optimization. We demonstrate this approach using these spectroscopically identified groups as the training set, i.e. zCOSMOS groups for PFOF searches within PS1 Medium Deep Field04 (PS1MD04) and DEEP2 EGS groups for searches in PS1MD07. We ultimately apply PFOF to four datasets spanning the photo-z uncertainty range from 0.01 to 0.06 in order to quantify the dependence of group recovery performance on photo-z accuracy. We find purities and completenesses calculated from observational datasets broadly agree with their mock analogues. Further tests of the PFOF algorithm are performed via matches to X-ray clusters identified within the PS1MD04 and COSMOS footprints. Across over a decade in group mass, we find PFOF groups match ~85% of X-ray clusters in COSMOS and PS1MD04, but at a lower statistical significance in the latter., Comment: 18 pages, 16 figures, 1 table. Submitted to ApJ

Published
2014

17. TIME DELAY BETWEEN IMAGES OF THE LENSED QUASAR UM673

Author

T. Akhunov, Alexander S. Gusev, Wen Ping Chen, O. A. Burkhonov, Alexey V. Sergeyev, V. V. Bruevich, S. N. Nuritdinov, O. V. Ezhkova, Ekaterina Koptelova, M. A. Ibragimov, Tzihong Chiueh, V. L. Oknyanskij, B. P. Artamonov, and Sh. A. Ehgamberdiev

Subjects
Physics, Brightness, Cosmology and Nongalactic Astrophysics (astro-ph.CO), lcsh:Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Time evolution, FOS: Physical sciences, Astronomy and Astrophysics, Quasar, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Light curve, lcsh:QB1-991, Amplitude, Space and Planetary Science, Observatory, Error analysis, Root-mean-square deviation, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract

We study brightness variations in the double lensed quasar UM673 (Q0142-100) with the aim of measuring the time delay between its two images. In the paper we combine our previously published observational data of UM673 obtained during the 2003 - 2005 seasons at the Maidanak Observatory with archival and recently observed Maidanak and CTIO UM673 data. We analyze the V, R and I-band light curves of the A and B images of UM673, which cover ten observational seasons from August 2001 to November 2010. We also analyze the time evolution of the difference in magnitudes between images A and B of UM673 over more than ten years. We find that the quasar exhibits both short-term (with amplitude of \sim 0.1 mag in the R band) and high-amplitude (\sim 0.3 mag) long-term variability on timescales of about several months and several years, respectively. These brightness variations are used to constrain the time delay between the images of UM673. From cross-correlation analysis of the A and B quasar light curves and error analysis we measure the mean time delay and its error of 89 \pm11 days. Given the input time delay of 88 days, the most probable value of the delay that can be recovered from light curves with the same statistical properties as the observed R-band light curves of UM673 is 95{+5/-16}{+14/-29} days (68 and 95 % confidence intervals). Analysis of the V - I color variations and V, R and I-band magnitude differences of the quasar images does not show clear evidence of the microlensing variations between 1998 and 2010., Comment: Submitted to A&A, 11 pages, 9 figures

Published
2012

18. Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01

Author

H. T. Liu, J. Ulbricht, P. Extermann, H. Hofer, G. Ambrosi, U. Becker, E. Perrin, C. Sbarra, W. J. Burger, F. J. Eppling, P. H. Fisher, S. M. Ting, M. Kraeber, Rui Miguel Faisca Rodrigues Pereira, Veronica Bindi, T. Kirn, M. Paniccia, C. dela Guia, A. Klimentov, Adrian Biland, M.W. Lee, M. Pimenta, Jouko Ritakari, Hui Zhang, S. Schael, I. D'Antone, D. Rapin, Sadakazu Haino, J. Casaus, Massimo Gervasi, Jungwook Shin, V. Plyaskin, P. Azzarello, F. Mayet, A. Schultz von Dratzig, D. Grandi, Andrea Contin, J.V. Allaby, L. Djambazov, Andrei Kounine, P. G. Rancoita, M. Pohl, B. Bertucci, Xiao-Dong Tang, J. P. Vialle, W.Z. Zhu, M. Capell, R. Siedling, Shih-Chang Lee, H. Park, L. Ao, J. Engelberg, M. Jongmanns, R. Kossakowski, H. von Gunten, D. Crespo, J. D. Burger, K. Lübelsmeyer, J. Alcaraz, K. Karlamaa, Yun-Young Choi, S. X. Wu, Eun-Suk Seo, T. S. Dai, S. Xu, Dawei Zhao, Federico Cindolo, Z.R. Dong, V. Shoutko, Joachim Trümper, Maria Ionica, Guohuai Zhu, V. Commichau, Z.P. Zhang, E. Shoumilov, E. Riihonen, A. Mihul, G.P. Barreira, M. J. Boschini, M. Ribordy, Tengfei Song, H. Anderhub, M. Duranti, U. Roeser, T. Siedenburg, H.F. Chen, M. Steuer, C. Delgado, Mao-Zhi Yang, Zhenghao Xu, A. Lebedev, Dong-Chul Son, H. Suter, G.S. Sun, A. Bartoloni, V. Koutsenko, Eino Valtonen, W. Wallraff, P.C. Xia, F. Spada, P. Saouter, J. Favier, Z. L. Ren, Waclaw Karpinski, X. D. Cai, Changgen Yang, I. Vetlitsky, W.H. Park, E. Cortina-Gil, G. Bruni, F. Palmonari, A. Pevsner, D. Vité, M. Buénerd, Tzihong Chiueh, S. R. Ro, S. Natale, G. Laurenti, S. Waldmeier Wicki, E. P. Velikhov, B. Zimmermann, R. Becker, Y. Galaktionov, Roald Z. Sagdeev, Ciaran Williams, Merja Tornikoski, J.L. Yan, Markus Cristinziani, J. J. Torsti, Antonino Zichichi, L. Bellagamba, K.S. Kim, A. Arefiev, F. Barao, R. R. McNeil, Jing Wang, G. Sartorelli, Nicola Tomassetti, P. Cannarsa, Y. H. Chang, T. Eronen, G. Kenney, M. Aguilar, Felicitas Pauss, V. Hermel, Werner Lustermann, Behcet Alpat, M. Basile, Z.G. Chen, G. Flügge, G. N. Kim, F. Spinella, M. Bourquin, H. L. Zhuang, J. Yang, You Zhou, Nicolas Produit, D. Luckey, F. Vezzu, G. Lu, C. Maña, C.H. Lin, Samuel C.C. Ting, Fabrizio Giulio Luca Pilo, G. Castellini, J. Vandenhirtz, D. Casadei, G. Laborie, P. Giusti, S. Di Falco, O. Grimm, Paolo Zuccon, A. Hasan, Mauro Menichelli, F. Giovacchini, G. Schwering, Daijin Kim, W.Q. Gu, F. Zhou, N. Fouque, I. Cernuda, E. Fiandrini, H. S. Chen, D. Santos, S. Urpo, G. Viertel, Luísa Arruda, G. Lamanna, K. Hangarter, Lucio Quadrani, B. Verlaat, P. Berges, Ari Mujunen, K. Wiik, J. Berdugo, G. Boella, N.A. Chernoplekov, Anselmo Margotti, W. Hungerford, Timo Laitinen, M. Pauluzzi, D. Ren, Giuseppe Levi, Lu Yuzhang, LinLi Yan, A.I. Oliva, V. Pojidaev, C. Lechanoine-Leluc, S.W. Ye, Roberto Battiston, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, AGUILAR M., ALCARAZ J., ALLABY J., ALPAT B., AMBROSI G., ANDERHUB H., AO L., AREFIEV A., ARRUDA L., AZZARELLO P., BASILE M., BARAO F., BARREIRA G., BARTOLONI A., BATTISTON R., BECKER R., BECKER U., BELLAGAMBA L., BERDUGO J., BERGES P., BERTUCCI B., BILAND A., BINDI V., BOELLA G., BOSCHINI M., BOURQUIN M., BRUNI G., BUENERD M., BURGER JD., BURGER WJ., CAI XD., CANNARSA P., CAPELL M., CASADEI D., CASAUS J., CASTELLINI G., CERNUDA I., CHANG YH., CHEN HF., CHEN HS., CHEN ZG., CHERNOPLEKOV NA., CHIUEH TH., CHOI YY., CINDOLO F., COMMICHAU V., CONTIN A., CORTINA-GIL E., CRESPO D., CRISTINZIANI M., DAI TS., DELA GUIA C., DELGADO C., DI FALCO S., DJAMBAZOV L., D'ANTONE I., DONG ZR., DURANTI M., ENGELBERG J., EPPLING FJ., ERONEN T., EXTERMANN P., FAVIER J., FIANDRINI E., FISHER PH., FLUGGE G., FOUQUE N., GALAKTIONOV Y., GERVASI M., GIOVACCHINI F., GIUSTI P., GRANDI D., GRIMM O., GU WQ., HAINO S., HANGARTER K., HASAN A., HERMEL V., HOFER H., HUNGERFORD W., IONICA M., JONGMANNS M., KARLAMAA K., KARPINSKI W., KENNEY G., KIM DH., KIM GN., KIM KS., KIRN T., KLIMENTOV A., KOSSAKOWSKI R., KOUNINE A., KOUTSENKO V., KRAEBER M., LABORIE G., LAITINEN T., LAMANNA G., LAURENTI G., LEBEDEV A., LECHANOINE-LELUC C., LEE MW., LEE SC., LEVI G., LIN CH., LIU HT., LU G., LU YS., LUBELSMEYER K., LUCKEY D., LUSTERMANN W., MANA C., MARGOTTI A., MAYET F., MCNEIL RR., MENICHELLI M., MIHUL A., MUJUNEN A., NATALE S., OLIVA A., PALMONARI F., PANICCIA M., PARK HB., PARK WH., PAULUZZI M., PAUSS F., PEREIRA R., PERRIN E., PEVSNER A., PILO F., PIMENTA M., PLYASKIN V., POJIDAEV V., POHL M., PRODUIT N., QUADRANI L., RANCOITA PG., RAPIN D., REN D., REN Z., RIBORDY M., RIIHONEN E., RITAKARI J., RO S., ROESER U., SAGDEEV R., SANTOS D., SARTORELLI G., SAOUTER P., SBARRA C., SCHAEL S., VON DRATZIG AS., SCHWERING G., SEO ES., SHIN JW., SHOUMILOV E., SHOUTKO V., SIEDENBURG T., SIEDLING R., SON D., SONG T., SPADA FR., SPINELLA F., STEUER M., SUN GS., SUTER H., TANG XW., TING SCC., TING SM., TOMASSETTI N., TORNIKOSKI M., TORSTI J., TRUMPER J., ULBRICHT J., URPO S., VALTONEN E., VANDENHIRTZ J., VELIKHOV E., VERLAAT B., VETLITSKY I., VEZZU F., VIALLE JP., VIERTEL G., VITE D., VON GUNTEN H., WICKI SW., WALLRAFF W., WANG JZ., WIIK K., WILLIAMS C., WU SX., XIA PC., XU S., XU ZZ., YAN JL., YAN LG., YANG CG., YANG J., YANG M., YE SW., ZHANG HY., ZHANG ZP., ZHAO DX., ZHOU F., ZHOU Y., ZHU GY., ZHU WZ., ZHUANG HL., ZICHICHI A., ZIMMERMANN B., ZUCCON P, Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Arruda, L, Azzarello, P, Basile, M, Barao, F, Barreira, G, Bartoloni, A, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bindi, V, Boella, G, Boschini, M, Bourquin, M, Bruni, G, Buénerd, M, Burger, J, Burger, W, Cai, X, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Cernuda, I, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiueh, T, Choi, Y, Cindolo, F, Commichau, V, Contin, A, Cortina Gil, E, Crespo, D, Cristinziani, M, Dai, T, dela Guia, C, Delgado, C, Di Falco, S, Djambazov, L, D’Antone, I, Dong, Z, Duranti, M, Engelberg, J, Eppling, F, Eronen, T, Extermann, P, Favier, J, Fiandrini, E, Fisher, P, Flügge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giovacchini, F, Giusti, P, Grandi, D, Grimm, O, Gu, W, Haino, S, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Hungerford, W, Ionica, M, Jongmanns, M, Karlamaa, K, Karpinski, W, Kenney, G, Kim, D, Kim, G, Kim, K, Kirn, T, Klimentov, A, Kossakowski, R, Kounine, A, Koutsenko, V, Kraeber, M, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lechanoine Leluc, C, Lee, M, Lee, S, Levi, G, Lin, C, Liu, H, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maña, C, Margotti, A, Mayet, F, Mcneil, R, Menichelli, M, Mihul, A, Mujunen, A, Natale, S, Oliva, A, Palmonari, F, Paniccia, M, Park, H, Park, W, Pauluzzi, M, Pauss, F, Pereira, R, Perrin, E, Pevsner, A, Pilo, F, Pimenta, M, Plyaskin, V, Pojidaev, V, Pohl, M, Produit, N, Quadrani, L, Rancoita, P, Rapin, D, Ren, D, Ren, Z, Ribordy, M, Riihonen, E, Ritakari, J, Ro, S, Roeser, U, Sagdeev, R, Santos, D, Sartorelli, G, Saouter, P, Sbarra, C, Schael, S, von Dratzig, A, Schwering, G, Seo, E, Shin, J, Shoumilov, E, Shoutko, V, Siedenburg, T, Siedling, R, Son, D, Song, T, Spada, F, Spinella, F, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tomassetti, N, Tornikoski, M, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Valtonen, E, Vandenhirtz, J, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Von Gunten, H, Wicki, S, Wallraff, W, Wang, J, Wiik, K, Williams, C, Wu, S, Xia, P, Xu, S, Xu, Z, Yan, J, Yan, L, Yang, C, Yang, J, Yang, M, Ye, S, Zhang, H, Zhang, Z, Zhao, D, Zhou, F, Zhou, Y, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, Zimmermann, B, Zuccon, P, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Becker, R., Becker, Ulrich J., Berges, P., Burger, Joseph D., Cai, Xudong, Capell, Michael H., Dai, T. S., Eppling, Frederic J., Fisher, Peter H., Klimentov, A., Kounine, Andrei, Koutsenko, Vladimir, Lebedev, Alexei, Luckey, P. David, Jr., Shoutko, V., Siedenburg, T., Steuer, M., Ting, Samuel C. C., Wu. S. X., Xu, S., and Zhou, F.

Subjects
Nuclear reaction, Astrophysics and Astronomy, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], genetic structures, Cosmic ray, Isotopes of boron, 01 natural sciences, High Energy Physics - Experiment, Nuclear physics, ACCELERATION OF PARTICLES, ABUNDANCES, Nucleosynthesis, 0103 physical sciences, Alpha Magnetic Spectrometer, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], acceleration of particles, cosmic rays, nuclear reactions, nucleosynthesis, abundances, 010303 astronomy & astrophysics, Cosmic ray spallation, Physics, NUCLEAR REACTIONS, NUCLEOSYNTHESIS, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astronomy and Astrophysics, COSMIC RAYS, FIS/01 - FISICA SPERIMENTALE, Space and Planetary Science, Isotopes of beryllium, Astrophysics - High Energy Astrophysical Phenomena, Heliosphere
Abstract

The variety of isotopes in cosmic rays allows us to study different aspects of the processes that cosmic rays undergo between the time they are produced and the time of their arrival in the heliosphere. In this paper, we present measurements of the isotopic ratios [superscript 2]H/[superscript 4]He, [superscript 3]He/[superscript 4]He, [superscript 6]Li/[superscript 7]Li, [superscript 7]Be/([superscript 9]Be+[superscript 10]Be), and [superscript 10]B/[superscript 11]B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The measurements are based on the data collected by the Alpha Magnetic Spectrometer, AMS-01, during the STS-91 flight in 1998 June., United States. Dept. of Energy, Massachusetts Institute of Technology

Published
2011
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19. GAMER with out-of-core computation

Author

Tzihong Chiueh, Yu-Chih Tsai, and Hsi-Yu Schive

Subjects
N-body simulation, Computer science, FOS: Physical sciences, Astronomy and Astrophysics, GPU cluster, Parallel computing, Riemann solver, CUDA, symbols.namesake, Space and Planetary Science, Virtual memory, symbols, Overhead (computing), Out-of-core algorithm, Central processing unit, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

GAMER is a GPU-accelerated Adaptive-MEsh-Refinement code for astrophysical simulations. In this work, two further extensions of the code are reported. First, we have implemented the MUSCL-Hancock method with the Roe's Riemann solver for the hydrodynamic evolution, by which the accuracy, overall performance and the GPU versus CPU speed-up factor are improved. Second, we have implemented the out-of-core computation, which utilizes the large storage space of multiple hard disks as the additional run-time virtual memory and permits an extremely large problem to be solved in a relatively small-size GPU cluster. The communication overhead associated with the data transfer between the parallel hard disks and the main memory is carefully reduced by overlapping it with the CPU/GPU computations., 4 pages, 4 figures, conference proceedings of IAU Symposium 270 (eds. Alves, Elmegreen, Girart, Trimble)

Published
2010

20. The Redshift Evolution of Wet, Dry, and Mixed Galaxy Mergers from Close Galaxy Pairs in the DEEP2 Galaxy Redshift Survey

Author

Kevin Casteels, Tzihong Chiueh, Sandra M. Faber, Michael C. Cooper, Benjamin J. Weiner, Lihwai Lin, Bau-Ching Hsieh, Gregory S. Novak, Jennifer M. Lotz, Christopher N. A. Willmer, Jeffrey A. Newman, Christopher J. Conselice, David R. Patton, and David C. Koo

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astrophysics (astro-ph), DEEP2 Redshift Survey, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy merger, Redshift survey, 01 natural sciences, Redshift, Galaxy, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Merge (version control), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

We study the redshift evolution of galaxy pair fractions and merger rates for different types of galaxies using kinematic pairs selected from the DEEP2 Redshift Survey. By parameterizing the evolution of the pair fraction as (1+z)^{m}, we find that the companion rate increases mildly with redshift with m = 0.41+-0.20 for all galaxies with -21 < M_B^{e} < -19. Blue galaxies show slightly faster evolution in the blue companion rate with m = 1.27+-0.35 while red galaxies have had fewer red companions in the past as evidenced by the negative slope m = -0.92+-0.59. We find that at low redshift the pair fraction within the red sequence exceeds that of the blue cloud, indicating a higher merger probability among red galaxies compared to that among the blue galaxies. With further assumptions on the merger timescale and the fraction of pairs that will merge, the galaxy major merger rates for 0.1 < z, 11 pages, 8 figures, ApJ Accepted, minor changes to match the journal proof version

Published
2008

21. AEGIS: Enhancement of Dust-enshrouded Star Formation in Close Galaxy Pairs and Merging Galaxies up to z ~ 1

Author

Puragra Guhathakurta, Andrew C. Phillips, Christopher J. Conselice, Emeric Le Floc'h, Alison L. Coil, Tzihong Chiueh, Michael C. Cooper, Jennifer M. Lotz, Steven P. Willner, Lihwai Lin, Kai G. Noeske, David C. Koo, Howard A. Smith, J.-S. Huang, Benjamin J. Weiner, and Christopher N. A. Willmer

Subjects
Physics, Stellar mass, 010308 nuclear & particles physics, Star formation, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy merger, Mass ratio, Redshift survey, 01 natural sciences, Galaxy, Luminosity, Extended Groth Strip, Space and Planetary Science, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Using data from the DEEP2 Galaxy Redshift Survey and HST/ACS imaging in the Extended Groth Strip, we select nearly 100 interacting galaxy systems including kinematic close pairs and morphologically identified merging galaxies. Spitzer MIPS 24 micron fluxes of these systems reflect the current dusty star formation activity, and at a fixed stellar mass (M_{*}) the median infrared luminosity (L_{IR}) among merging galaxies and close pairs of blue galaxies is twice (1.9 +/- 0.4) that of control pairs drawn from isolated blue galaxies. Enhancement declines with galaxy separation, being strongest in close pairs and mergers and weaker in wide pairs compared to the control sample. At z ~ 0.9, 7.1% +/- 4.3% of massive interacting galaxies (M_{*} > 2*10^{10} M_{solar}) are found to be ULIRGs, compared to 2.6% +/- 0.7% in the control sample. The large spread of IR luminosity to stellar mass ratio among interacting galaxies suggests that this enhancement may depend on the merger stage as well as other as yet unidentified factors (e.g., galaxy structure, mass ratio, orbital characteristics, presence of AGN or bar). The contribution of interacting systems to the total IR luminosity density is moderate (, 12 pages, 2 figures, 1 table, minor changes to match the proof version, accepted for publication in the ApJL AEGIS Special Issue

Published
2006

22. Jeans analysis for dwarf spheroidal galaxies in wave dark matter.

Author

Shu-Rong Chen, Hsi-Yu Schive, and Tzihong Chiueh

Subjects
DARK matter, REDSHIFT, ASTROPHYSICS, DWARF galaxies, BARYONICHIDAE
Abstract

Although still under debate, observations generally suggest that dwarf spheroidal (dSph) galaxies exhibit large constant-density cores in the centres, which can hardly be explained by dissipationless cold dark matter simulations without baryonic feedback. Wave dark matter (ψDM), characterized by a single parameter, the dark matter particle mass mψ, predicts a central soliton core in every galaxy arising from quantum pressure against gravity. Here we apply Jeans analysis assuming a soliton core profile to the kinematic data of eight classical dSphs so as to constrain mψ, and obtain mψ=1.18-0.24+0.28 x 10-22 and 1.79-0.33+0.35 x 10-22eV(2σ) using the two different observational data sets of Walker et al. We show that the estimate of mψ is sensitive to the dSph kinematic data sets and is robust to various models of stellar density profile. We also consider multiple stellar subpopulations in dSphs and find consistent results. This mass range of mψ is in good agreement with other independent estimates, such as the high-redshift luminosity functions, the reionization history and the Thomson optical depth to the cosmic microwave background. [ABSTRACT FROM AUTHOR]

Published
2017
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23. An Analytical Approach to the Spin-Distribution of Dark Halos

Author

Lihwai Lin, Jounghun Lee, and Tzihong Chiueh

Subjects
Physics, Angular momentum, Dark matter, Astrophysics (astro-ph), Scalar (physics), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Power law, Specific relative angular momentum, Space and Planetary Science, Quantum mechanics, Log-normal distribution, Halo, Dimensionless quantity
Abstract

We derive the distribution of the dimensionless specific angular momentum of dark matter halos, $P(j)$, in the framework of the standard tidal torque theory, and explain the characteristic shape of $P(j)$ commonly observed in N-body simulations. A scalar quantity (shear scalar), $r$, is introduced for measuring the effective strength of the tidal torque force acting upon the halo from the surrounding matter. It is found that the ubiquitous and broad shape of $P(j)$ can mostly be attributed to the unique property of the shear scalar $r$, and also that $P(j)$ is insensitve to the underlying collapse dynamics. Our result demonstrates that although the shape of $P(j)$ is ubiquitous and close to log-normal, the distribution is not exactly log-normal but decays exponentially at the high angular momentum end, and drops slowly as a power-law with an index 2 at the low angular momentum end., 14 pages including two figures, submitted to ApJ Lett

Published
2002

24. The Alpha Magnetic Spectrometer (AMS) on the International Space Station: Part I – results from the test flight on the space shuttle

Author

P. Extermann, H. Hofer, J.P. Richeux, Jose Maria Kenny, M. Jongmanns, H. Anderhub, P. Giusti, A. Hasan, Mauro Menichelli, G. Scolieri, Y.S. Lu, I. Lopes, S. Ro, G. Schwering, Eun-Suk Seo, L. Baldini, E. Lanciotti, F. Vezzu, Maria Ionica, S.W. Ye, V. Koutsenko, Eino Valtonen, M.Y. Kim, G. Sartorelli, D. Rapin, V. Plyaskin, Werner Lustermann, Behcet Alpat, W.Q. Gu, W.Z. Zhu, C. Delgado, E. Fiandrini, Yu. Galaktionov, D.H. Kim, J. Alcaraz, S. X. Wu, W.H. Park, Felicitas Pauss, B. Verlaat, P. Berges, K. Karlamaa, S.C.C. Ting, F. Palmonari, Zhenghao Xu, Zhuoxiang Ren, F. Velcea, Tzihong Chiueh, G. Barbier, H.B. Park, R. Kossakowski, A. Klimentov, S. Urpo, Ari Mujunen, A. Lebedev, Dong-Chul Son, G. Laurenti, K. Luebelsmeyer, E. Shoumilov, W. Hungerford, H. S. Chen, N. Produit, M. Buenerd, S. Waldmeier Wicki, M. Basile, E. Riihonen, A. Mihul, Timo Laitinen, J. Yang, V. Postolache, V. Pojidaev, M. Steuer, P.C. Xia, G.S. Sun, Jian Wang, M. Ribordy, K. Hangarter, H. L. Zhuang, M. Pauluzzi, Stefan Schael, H. Suter, Guohuai Zhu, G. Boella, X.W. Tang, M. Kraber, A. Pevsner, M. A. Huang, Mao-Zhi Yang, Tao Song, J.L. Yan, N.A. Chernoplekov, J. Vandenhirtz, Z.G. Chen, C. Camps, Ciaran Williams, D. Ren, D. Luckey, I. Vetlitsky, Samuel C.C. Ting, N. Dinu, Zhidong Zhang, Anselmo Margotti, E. Cortina-Gil, M. Bourquin, A. Papi, Adrian Biland, R. Ionica, L. Djambazov, Paolo Zuccon, A. Contin, I. D'Antone, M.W. Lee, Jungwook Shin, F. Barao, G. Castellini, J. P. Da Cunha, Gui Nyun Kim, N. Fouque, P. Levtchenko, Massimo Gervasi, Kyung-Suk Cho, J. D. Burger, F. Mayet, M. Pohl, P. Yeh, G. Lu, C. Maña, C. Lechanoine-Leluc, A. Schultz von Dratzig, C. Rossin, Hengchang Liu, A. Mourao, S. Blasko, G. Laborie, C. Sbarra, Peter H. Fisher, L.G. Yan, V. Hermel, J.D. Deus, X. D. Cai, M.J. Choi, O. Grimm, J. Casaus, M. Capell, Philipp Azzarello, R. Siedling, J. Berdugo, Yun Wang, A. Arefiev, Roald Z. Sagdeev, J. Engelberg, H. von Gunten, C.L. Liu, L. Bellagamba, Changgen Yang, D. Casadei, U. Roser, R. R. McNeil, B. Meillon, Giuseppe Levi, Y.L. Chuang, K. Wiik, P. Bene, Federico Cindolo, J. J. Torsti, Antonino Zichichi, L. Brocco, J. Ritakari, Y. H. Chang, G. Kenney, P. Cannarsa, Y.Y. Choi, D. Barancourt, J. Favier, Waclaw Karpinski, E. Babucci, U. Becker, Dawei Zhao, R. Becker, Z.R. Dong, E. Perrin, K.S. Kim, Claudia Cecchi, F. J. Eppling, M. Aguilar, V. Shoutko, S. Bizzaglia, G. Esposito, M. Pimenta, G. Fluegge, D. Grandi, B. Bertucci, D. Santos, G. Ambrosi, T. S. Dai, A. Pesci, B.C. Wang, D. Vité, G. Lamanna, G. Viertel, J. P. Vialle, H.F. Chen, G.P. Barreira, W. J. Burger, Frank Raupach, Roberto Battiston, L. Ao, J. Ulbricht, Hao Zhang, S.C. Lee, J. Trümper, P. Emonet, M. J. Boschini, V. Commichau, E. P. Velikhov, B. Zimmermann, Merja Tornikoski, Markus Cristinziani, T. Eronen, P. G. Rancoita, W. Wallraff, G. Bruni, Aguilar, M, Alcaraz, J, Allaby, J, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Boschini, M, Bourquin, M, Brocco, L, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Cecchi, C, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiueh, T, Cho, K, Choi, M, Choi, Y, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Cortina-Gil, E, Cristinziani, M, da Cunha, J, Dai, T, Delgado, C, Deus, J, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Engelberg, J, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Fiandrini, E, Fisher, P, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Grandi, D, Grimms, O, Gu, W, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Jongmanns, M, Karlamaa, K, Karpinski, W, Kenney, G, Kenny, J, Kim, D, Kim, G, Kim, K, Kim, M, Klimentov, A, Kossakowski, R, Koutsenko, V, Kraeber, M, Laborie, G, Laitinen, T, Lamanna, G, Lanciotti, E, Laurenti, G, Lebedev, A, Lechanoine-Leluc, C, Lee, M, Lee, S, Levi, G, Levtchenko, P, Liu, C, Liu, H, Lopes, I, Lu, G, Lu, Y, Lubelsmeyer, K, Luckey, D, Lustermann, W, Mana, C, Margotti, A, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mihul, A, Mourao, A, Mujunen, A, Palmonari, F, Papi, A, Park, H, Park, W, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pimenta, M, Plyaskin, V, Pojidaev, V, Pohl, M, Postolache, V, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Ro, S, Roeser, U, Rossin, C, Sagdeev, R, Santos, D, Sartorelli, G, Sbarra, C, Schael, S, von Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shin, J, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tornikoski, M, Torsti, J, Trumper, J, Ulbricht, J, Urpo, S, Valtonen, E, Vandenhirtz, J, Velcea, F, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, V, Jp, Viertel, G, Vite, D, Von Gunten, H, Wicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wiik, K, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, J, Yang, M, Ye, S, Yeh, P, Xu, Z, Zhang, H, Zhang, Z, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, Zimmermann, B, Zuccon, P, Ambrosi, Giovanni, Azzarello, Philipp, Bene, Pierre, Bourquin, Maurice, Cortina Gil, Eduardo, Cristinziani, Markus, Emonet, Pascal Philippe, Extermann, Pierre, Leluc, Catherine, Perrin, Eric, Pohl, Martin, Produit, Nicolas, Rapin, Divic Jean, Ribordy, Mathieu, Richeux, Jean-Pierre, Vite, Davide, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, CIEMAT, E-28040, Madrid, Spain, and UCL - SST/IRMP - Institut de recherche en mathématique et physique

Subjects
Physics, 010308 nuclear & particles physics, FIS/06 - FISICA PER IL SISTEMA TERRA E PER IL MEZZO CIRCUMTERRESTRE, General Physics and Astronomy, chemistry.chemical_element, Electron, ddc:500.2, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nuclear physics, FIS/05 - ASTRONOMIA E ASTROFISICA, Positron, Earth's magnetic field, FIS/01 - FISICA SPERIMENTALE, chemistry, 13. Climate action, Antiproton, 0103 physical sciences, Alpha Magnetic Spectrometer, Nucleon, 010303 astronomy & astrophysics, AMS, Cosmic Rays, Antimatter, Helium, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
Abstract

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 (June 1998) in a 51.7 deg orbit at altitudes between 320 and 390 km. A search for antihelium nuclei in the rigidity range 1–140 GV was performed. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1×10^−6 was obtained. The high energy proton, electron, positron, helium, antiproton and deuterium spectra were accurately measured. For each particle and nuclei two distinct spectra were observed: a higher energy spectrum and a substantial second spectrum. Positrons in the second spectrum were found to be much more abundant than electrons. Tracing particles from the second spectra shows that most of them travel for an extended period of time in the geomagnetic field, and that the positive particles (p and e+) and negative ones (e−) originate from two complementary geographic regions. The second helium spectrum flux over the energy range 0.1–1.2 GeV/nucleon was measured to be (6.3 ± 0.9) × 10^−3(m^2 s sr)^−1. Over 90 percent of the helium flux was determined to be 3He at the 90% confidence level

Published
2002
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25. Dynamics of Multi-Component, Multi-Field Quintessence

Author

Tzihong Chiueh

Subjects
Physics, High Energy Physics - Theory, Nuclear and High Energy Physics, Astrophysics (astro-ph), FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, General Relativity and Quantum Cosmology, Quantization (physics), Classical mechanics, High Energy Physics - Theory (hep-th), Lorentz scalar, Boson, Quintessence
Abstract

Dynamics of the multi-component, multi-field quintessence and gravity is formulated as relativistic N-particle dynamics, embedded in a static viscus flat space and under the forces given by an interacting Lorentz scalar potential via exchange of field bosons. The Ratra-Peebles power-law potential of effective single-field quintessence can be derived from this microscopic perspective. In certain situations, the effective dynamics can be made identical to that of the single complex quintessence, except for that the overall U(1) symmetry is not manifestly broken. The present formulation provides a convenient gauge for analyzing the superhorizon perturbations and possibly for quantization of superhorizon fields and gravity., 29 pages. submitted to PRD

Published
2001

26. On the Nonspherical Nature of Halo Formation

Author

Jounghun Lee and Tzihong Chiueh

Subjects
Physics, Structure formation, Astrophysics (astro-ph), Monte Carlo method, FOS: Physical sciences, Collapse (topology), Astronomy and Astrophysics, Astrophysics, Function (mathematics), Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy, Spherical model, Classical mechanics, Space and Planetary Science, Physics::Space Physics, Physics::Atomic and Molecular Clusters, Halo, Random matrix
Abstract

We present a new collapse condition to describe the formation of dark halos via nonspherical gravitational clustering. This new nonspherical collapse condition is obtained by the logical generalization of the spherical model to the nonspherical one. By solving a diffusion-like random matrix equation with the help of the Monte Carlo method, we show that this nonspherical collapse condition yields the mass function derived by Sheth & Tormen (1999) which has been shown to be in excellent agreement with the recent N-body results of high resolution. We expect that this nonspherical collapse condition might provide us a deeper insight into the structure formation, and suggest that it should be widely applied to various cosmological issues such as the galaxy merging history, the galaxy bias, and so forth., Accepted version, ApJ in press, LaTex file, 1 ps figure, mistakes and typos corrected

Published
2000

27. Search for antihelium in cosmic rays

Author

Z.R. Dong, S. Bizzaglia, G. Ambrosi, J. Casaus, M. Pimenta, T. S. Dai, Samuel C.C. Ting, L. Djambazov, B.C. Wang, G. Molinari, A. Klimentov, B. Bertucci, S. X. Wu, R. Pilastrini, G. Lamanna, L.G. Yan, R. Siedling, J. Favier, Philipp Azzarello, J. J. Torsti, Antonino Zichichi, A. Hasan, Mauro Menichelli, L. Ao, Inkyu Park, J.P. Vialle, M. Steuer, P.C. Xia, Peter H. Fisher, Ilya Usoskin, P. G. Rancoita, Jing Wang, F. Palmonari, J. Isbert, M. Ribordy, G. Boella, H. von Gunten, P. Crespo, W. J. Burger, N. Fouque, R. Ionica, Federico Cindolo, J.P. Richeux, R. Cavalletti, D.X. Zhao, U. Roeser, N.A. Chernoplekov, C. G. Yang, Nicolas Produit, M. Buenerd, A. Cotta-Ramusino, R. Flaminio, J. P. Da Cunha, Anselmo Margotti, D. Rapin, V. Plyaskin, W. Kim, Roberto Battiston, G.Y. Zhu, W.Z. Zhu, G. Fluegge, G. Bruni, G. Viertel, P. Levtchenko, E. Fiandrini, G. Laurenti, K. Luebelsmeyer, S. Waldmeier Wicki, S.C. Lee, Yu. Galaktionov, F. Massera, D. Vité, J. Ulbricht, A. Chiarini, Hao Zhang, H. S. Chen, C. Rossin, G. Pancaldi, Felicitas Pauss, S. Recupero, Ciaran Williams, R. Kossakowski, W. Karpinski, J. Alcaraz, F. Barao, P. Yeh, E. Emonet, L.K. Ding, H.T. Liu, E. P. Velikhov, G. Torromeo, M. Basile, G.S. Sun, A. Pevsner, J.L. Yan, X. D. Cai, L. Baldini, F. Mezzanotte, C.L. Liu, L. Bellagamba, S. Blasko, K. Hangarter, J. Berdugo, Adrian Biland, G. Barbier, J. Vandenhirtz, V. Hermel, A. Arefiev, E. Prati, Jose Maria Kenny, R. R. McNeil, T.G. Guzik, B. Meillon, W.K. Gu, G. Kenney, I. D'Antone, J.P. Wefel, Markus Cristinziani, T. Eronen, R. Becker, Y.L. Chuang, P. Bene, B. Alpat, D. Luckey, E. Riihonen, A. Mihul, M. Jongmanns, C.C. Feng, D. Casadei, W. Wallraff, J. Krieger, H.L. Zhuang, G. Castellini, Massimo Gervasi, Zhuoxiang Ren, G. Schwering, W. Hungerford, A. Papi, Timo Laitinen, D. Santos, F. Tenbusch, B. Verlaat, P. Berges, Raffaele Mezzenga, S. Urpo, Ari Mujunen, G. Laborie, V. Shoutko, M. Pauluzzi, Y. S. Lu, G.P. Barreira, Yun Wang, V. Commichau, J. Truemper, A. Pesci, D. Ren, M. Capell, V. Koutsenko, Eino Valtonen, F. Vezzu, P. Cannarsa, C. Camps, T.P. Li, M. Ionica, H. Postema, A. Contin, M. Yang, E. Babucci, U. Becker, A. Lebedev, Dong-Chul Son, P. Giusti, I. Lopes, E. Perrin, F. J. Eppling, D. Alvisi, G. Lu, F. Raupach, C. Maña, P. Extermann, S. M. Ting, H. Hofer, G. Esposito, I. Vetlitsky, G. Sartorelli, M. Lolli, G. Maehlum, E.A. Werner, Fabio Finelli, Z.G. Chen, Werner Lustermann, Giuseppe Levi, X. W. Tang, Tao Song, M. Bourquin, V. Pojidaev, E. Shoumilov, H. Suter, J. D. Burger, Roald Z. Sagdeev, A. Mourao, J. Ritakari, Y. H. Chang, D. Barancourt, N. Dinu, H. Anderhub, Tzihong Chiueh, M. A. Huang, Jorge Dias de Deus, F. Mayet, A. Schultz von Dratzig, Alcaraz, J, Alvisi, D, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Barancourt, D, Barao, F, Barbier, G, Barreira, G, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Béné, P, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Bourquin, M, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Cavalletti, R, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiarini, A, Chiueh, T, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Cotta Ramusino, A, Crespo, P, Cristinziani, M, Dacunha, J, Dai, T, Deus, J, Ding, L, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Feng, C, Fiandrini, E, Finelli, F, Fisher, P, Flaminio, R, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Gu, W, Guzik, T, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Isbert, J, Jongmanns, M, Karpinski, W, Kenney, G, Kenny, J, Kim, W, Klimentov, A, Krieger, J, Kossakowski, R, Koutsenko, V, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lee, S, Levi, G, Levtchenko, P, Li, T, Liu, C, Liu, H, Lolli, M, Lopes, I, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maehlum, G, Maña, C, Margotti, A, Massera, F, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mezzanotte, F, Mezzenga, R, Mihul, A, Molinari, G, Mourao, A, Mujunen, A, Palmonari, F, Pancaldi, G, Papi, A, Park, I, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pilastrini, R, Pimenta, M, Plyaskin, V, Pojidaev, V, Postema, H, Prati, E, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Recupero, S, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Roeser, U, Roissin, C, Sagdeev, R, Santos, D, Sartorelli, G, Schultzvondratzig, A, Schwering, G, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tenbusch, F, Torromeo, G, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Usoskin, I, Valtonen, E, Vandenhirtz, J, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Vongunten, H, Waldmeierwicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wefel, J, Werner, E, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, M, Yeh, P, Zhang, H, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), and AMS

Subjects
Astrophysics and Astronomy, Nuclear and High Energy Physics, FOS: Physical sciences, chemistry.chemical_element, Space Shuttle, Cosmic ray, Astrophysics, 7. Clean energy, 01 natural sciences, High Energy Physics - Experiment, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], High Energy Physics - Experiment (hep-ex), FIS/05 - ASTRONOMIA E ASTROFISICA, Rigidity (electromagnetism), 0103 physical sciences, Alpha Magnetic Spectrometer, 010306 general physics, Helium, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), Astronomy, Flux ratio, FIS/01 - FISICA SPERIMENTALE, chemistry, Cosmic rays: anti-helium, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE
Abstract

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained., 18 pages, Latex, 9 .eps figures

Published
2000

28. Leptons in near earth orbit

Author

L. Djambazov, P. Giusti, G. Scolieri, I. Lopes, Dawei Zhao, P. G. Rancoita, E. Babucci, U. Becker, F. Vezzu, E. Perrin, F. J. Eppling, G. Barbier, S. M. Ting, S.C. Lee, R. Ionica, F. Palmonari, H. von Gunten, G. Esposito, Z.R. Dong, Federico Cindolo, Changgen Yang, H. T. Liu, Diego Casadei, Yu. Galaktionov, D. Vité, A. Lebedev, U. Roeser, G. Castellini, Dong-Chul Son, Z. L. Ren, J. Alcaraz, Guohuai Zhu, Yun Wang, S. Bizzaglia, A. Arefiev, P. Extermann, H. Hofer, W. Wallraff, Ilya Usoskin, Jing Wang, P. Levtchenko, P. Emonet, T. S. Dai, H. Anderhub, Waclaw Karpinski, E. Fiandrini, R. Becker, P. Cannarsa, R. R. McNeil, D. Rapin, C. Roissin, B.C. Wang, M. Pimenta, E. P. Velikhov, B. Zimmermann, V. Plyaskin, Roald Z. Sagdeev, B. Meillon, H. S. Chen, L. Baldini, J. Casaus, A. Hasan, E. Riihonen, Mauro Menichelli, K. Karlamaa, A. Mihul, Giovanna Bruni, G. Kenney, N. Produit, D. Grandi, M. Ribordy, S. Urpo, W. J. Burger, Merja Tornikoski, Markus Cristinziani, G. Schwering, A. Pesci, I. Vetlitsky, L.G. Yan, I. D'Antone, Y. H. Chang, Tengfei Song, W.Q. Gu, B. Bertucci, D. Barancourt, N. Dinu, V. Commichau, G. Laborie, P. Crespo, Mao-Zhi Yang, J. J. Torsti, M. Jongmanns, Antonino Zichichi, Adrian Biland, V. Postolache, Peter H. Fisher, T. Eronen, C. Camps, J. Berdugo, N. Fouque, J. P. Da Cunha, Massimo Gervasi, J. Vandenhirtz, H. F. Chen, F. Barao, S. Blasko, Zhenyu Zhang, H.L. Zhuang, G. Viertel, E. Shoumilov, Jose Maria Kenny, W. Hungerford, F. Velcea, Y.L. Chuang, O. Grimm, J.L. Yan, K. Wiik, P. Bene, H. Suter, J.P. Richeux, Tzihong Chiueh, V. Hermel, M. Buenerd, Timo Laitinen, M. Capell, A. Papi, Eun-Suk Seo, M. Pauluzzi, R. Siedling, G. Fluegge, W.Z. Zhu, Giovanni Ambrosi, L. Ao, M. Bourquin, D. Ren, G. Lu, C. Maña, V. Koutsenko, Eino Valtonen, Felicitas Pauss, R. Kossakowski, A. Klimentov, G.S. Sun, A. Contin, Samuel C.C. Ting, M. A. Huang, M. J. Boschini, M. Basile, K. Hangarter, Roberto Battiston, A. Pevsner, D. Luckey, F. Mayet, Ciaran Williams, J. Ulbricht, A. Schultz von Dratzig, P. Yeh, G. Laurenti, Claudia Cecchi, S. Waldmeier Wicki, Hao Zhang, Z.G. Chen, S. X. Wu, J. Ritakari, X. D. Cai, J. Trümper, V. Shoutko, Inkyu Park, M. Steuer, P.C. Xia, S.W. Ye, C.L. Liu, L. Bellagamba, G. Lamanna, J. Engelberg, Xiao-Dong Tang, J. P. Vialle, K. Lübelsmeyer, G.P. Barreira, M. Ionica, P. Azzarello, Z. Z. Xu, V. Pojidaev, B. Verlaat, G. Sartorelli, P. Berges, Giuseppe Levi, Lu Yuzhang, Ari Mujunen, Werner Lustermann, Behcet Alpat, J. D. Burger, Frank Raupach, A. Mourao, J.D. Deus, L. Brocco, G. Boella, N.A. Chernoplekov, Anselmo Margotti, W. Kim, M. Kraeber, J. Favier, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AMS, Alcaraz, J, Alpat, B, Ambrosi, G, Anderhub, H, Ao, L, Arefiev, A, Azzarello, P, Babucci, E, Baldini, L, Basile, M, Barancourt, D, Barao, F, Barbier, G, Barreira, G, Battiston, R, Becker, R, Becker, U, Bellagamba, L, Béné, P, Berdugo, J, Berges, P, Bertucci, B, Biland, A, Bizzaglia, S, Blasko, S, Boella, G, Boschini, M, Bourquin, M, Brocco, L, Bruni, G, Buenerd, M, Burger, J, Burger, W, Cai, X, Camps, C, Cannarsa, P, Capell, M, Casadei, D, Casaus, J, Castellini, G, Cecchi, C, Chang, Y, Chen, H, Chen, Z, Chernoplekov, N, Chiueh, T, Chuang, Y, Cindolo, F, Commichau, V, Contin, A, Crespo, P, Cristinziani, M, Cunha, J, Dai, T, Deus, J, Dinu, N, Djambazov, L, D'Antone, I, Dong, Z, Emonet, P, Engelberg, J, Eppling, F, Eronen, T, Esposito, G, Extermann, P, Favier, J, Fiandrini, E, Fisher, P, Fluegge, G, Fouque, N, Galaktionov, Y, Gervasi, M, Giusti, P, Grandi, D, Grimm, O, Gu, W, Hangarter, K, Hasan, A, Hermel, V, Hofer, H, Huang, M, Hungerford, W, Ionica, M, Ionica, R, Jongmanns, M, Karlamaa, K, Karpinski, W, Kenney, G, Kenny, J, Kim, W, Klimentov, A, Kossakowski, R, Koutsenko, V, Kraeber, M, Laborie, G, Laitinen, T, Lamanna, G, Laurenti, G, Lebedev, A, Lee, S, Levi, G, Levtchenko, P, Liu, C, Liu, H, Lopes, I, Lu, G, Lu, Y, Lübelsmeyer, K, Luckey, D, Lustermann, W, Maña, C, Margotti, A, Mayet, F, Mcneil, R, Meillon, B, Menichelli, M, Mihul, A, Mourao, A, Mujunen, A, Palmonari, F, Papi, A, Park, I, Pauluzzi, M, Pauss, F, Perrin, E, Pesci, A, Pevsner, A, Pimenta, M, Plyaskin, V, Pojidaev, V, Postolache, V, Produit, N, Rancoita, P, Rapin, D, Raupach, F, Ren, D, Ren, Z, Ribordy, M, Richeux, J, Riihonen, E, Ritakari, J, Roeser, U, Roissin, C, Sagdeev, R, Sartorelli, G, Dratzig, A, Schwering, G, Scolieri, G, Seo, E, Shoutko, V, Shoumilov, E, Siedling, R, Son, D, Song, T, Steuer, M, Sun, G, Suter, H, Tang, X, Ting, S, Tornikoski, M, Torsti, J, Trümper, J, Ulbricht, J, Urpo, S, Usoskin, I, Valtonen, E, Vandenhirtz, J, Velcea, F, Velikhov, E, Verlaat, B, Vetlitsky, I, Vezzu, F, Vialle, J, Viertel, G, Vité, D, Gunten, H, Wicki, S, Wallraff, W, Wang, B, Wang, J, Wang, Y, Wiik, K, Williams, C, Wu, S, Xia, P, Yan, J, Yan, L, Yang, C, Yang, M, Ye, S, Yeh, P, Xu, Z, Zhang, H, Zhang, Z, Zhao, D, Zhu, G, Zhu, W, Zhuang, H, Zichichi, A, and Zimmermann, B

Subjects
Nuclear and High Energy Physics, Cosmic Rays, AMS, Cosmic ray, Electron, Astrophysics, Kinetic energy, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nuclear physics, FIS/05 - ASTRONOMIA E ASTROFISICA, AMS-01, 0103 physical sciences, Alpha Magnetic Spectrometer, AMS, 010306 general physics, 010303 astronomy & astrophysics, Physics, Earth's orbit, Cosmic rays: leptons, Cosmic Rays, cosmic rays, AMS-01, FIS/01 - FISICA SPERIMENTALE, Earth's magnetic field, 13. Climate action, High Energy Physics::Experiment, FIS/04 - FISICA NUCLEARE E SUBNUCLEARE, Lepton
Abstract

The lepton spectra in the kinetic energy ranges 0.2 to 40 GeV for e − and 0.2 to 3 GeV for e + were measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS–91 at altitudes near 380 km. From the origin of the leptons two distinct spectra were observed: a higher energy spectrum and a substantial second spectrum with positrons much more abundant than electrons. Tracing leptons from the second spectra shows that most of these leptons travel for an extended period of time in the geomagnetic field and that the e + and e − originate from two complementary geographic regions.

Published
2000

29. SHARP – III. First use of adaptive-optics imaging to constrain cosmology with gravitational lens time delays.

Author

Chen, Geoff C.-F., Suyu, Sherry H., Wong, Kenneth C., Fassnacht, Christopher D., Tzihong Chiueh, I Shing Hu, Auger, Matthew W., Koopmans, Léon V. E., Lagattuta, David J., McKean, John P., Vegetti, Simona, and Halkola, Aleksi

Subjects
METAPHYSICAL cosmology, GRAVITATIONAL lenses, OPTICAL images, CONSTRAINTS (Physics), TIME delay systems
Abstract

Accurate and precise measurements of the Hubble constant are critical for testing our current standard cosmological model and revealing possibly new physics. With Hubble Space Telescope (HST) imaging, each strong gravitational lens system with measured time delays can allow one to determine the Hubble constant with an uncertainty of ∼7 per cent. Since HST will not last forever, we explore adaptive-optics (AO) imaging as an alternative that can provide higher angular resolution than HST imaging but has a less stable point spread function (PSF) due to atmospheric distortion. To make AO imaging useful for time-delay-lens cosmography, we develop a method to extract the unknown PSF directly from the imaging of strongly lensed quasars. In a blind test with two mock data sets created with different PSFs, we are able to recover the important cosmological parameters (time-delay distance, external shear, lens-mass profile slope, and total Einstein radius). Our analysis of the Keck AO image of the strong lens system RXJ 1131−1231 shows that the important parameters for cosmography agree with those based on HST imaging and modelling within 1σ uncertainties. Most importantly, the constraint on the model time-delay distance by using AO imaging with 0.09 arcsec resolution is tighter by ∼50 per cent than the constraint of time-delay distance by using HST imaging with 0.09 arcsec when a power-law mass distribution for the lens system is adopted. Our PSF reconstruction technique is generic and applicable to data sets that have multiple nearby point sources, enabling scientific studies that require high-precision models of the PSF. [ABSTRACT FROM AUTHOR]

Published
2016
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32. SIMULATION OF A COMBINED SZE AND WEAK LENSING CLUSTER SURVEY FOR AMIBA EXPERIMENT.

Author

Keiichi Umetsu, Tzihong Chiueh, Kai-Yang Lin, Jun-Mein Wu, and Yao-Huan Tseng

Subjects
*GALAXY clusters, *SUPERCLUSTERS, *REDSHIFT, *ASTRONOMY, *ASTROPHYSICS, *METAPHYSICAL cosmology
Abstract

We present simulations of interferometric Sunyaev-Zel'dovich effect (SZE) and optical weak lenisng observations for the forthcoming AMiBA experiment, aiming at searching for high-redshift clusters of galaxies. On the basis of simulated sky maps, we have derived theoretical halo number counts and redshift distributions of selected halo samples for an AMiBA SZE survey and a weak lensing follow-up survey. By utilizing the conditional number counts of weak lensing halos with the faint SZE detection, we show that a combined SZE and weak lensing survey can gain an additional fainter halo sample at a given false positive rate, which cannot be obtained from either survey alone. [ABSTRACT FROM AUTHOR]

Published
2004
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33. INTERFEROMETRIC MEASUREMENTS OF ANNULUS-FILTERED POLARIZATIONS PATTERNS IN THE CMB.

Author

Cheng-Jiun Ma and Tzihong Chiueh

Subjects
*INTERFEROMETRY, *OPTICAL measurements, *POLARIZATION (Nuclear physics), *RADIATION, *PARTICLES (Nuclear physics), *NUCLEAR physics
Abstract

Due to the finite-size beam, interferometry observations of the CMB polarization tend to measure a mixture of E and B modes arising from uw-space smearing. We propose an interferometry observation strategy that can disentangle the polarization E and B modes in a clean manner. This strategy employs a similar principle as that of the single-dish observation proposed earlier, but requiring additional linear combinations of signals measured from different baselines. In this work, we consider a hexagonally packed interferometry array as an example to demonstrate the ultility and efficiency of the proposed method. The measurement from a unit cell of equilateral triangular baselines in interferometry measurement is found to be comparable to that from a single dish in single-dish measurements. [ABSTRACT FROM AUTHOR]

Published
2004
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34. Soliton Random Walk and the Cluster-Stripping Problem in Ultralight Dark Matter.

Author

Hsi-Yu Schive, Tzihong Chiueh, and Broadhurst, Tom

Subjects
*RANDOM walks, *DARK matter, *STAR clusters, *MILKY Way
Abstract

Simulations of ultralight, ~10-22 eV, bosonic dark matter exhibit rich wavelike structure, including a soliton core within a surrounding halo that continuously self-interferes on the de Broglie scale. We show here that as an inherent consequence, the soliton undergoes a confined random walk at the base of the halo potential. This is significant for the fate of the ancient central star cluster in Eridanus II, as the agitated soliton gravitationally shakes the star cluster in and out of the soliton on a timescale of ~100 Myr, so complete tidal disruption of the star cluster can occur within ~1 Gyr. This destructive effect can be mitigated by tidal stripping of the halo of Eridanus II, thereby reducing the agitation, depending on its orbit around the Milky Way. Our simulations show the Milky Way tide affects the halo much more than the soliton, so the star cluster in Eridanus II can survive for over 5 Gyr within the soliton if it formed after significant halo stripping. [ABSTRACT FROM AUTHOR]

Published
2020
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35. Evolution of perturbation and power spectrum in a two-component ultralight axionic universe.

Author

Yi-Hsiung Hsu and Tzihong Chiueh

Subjects
*POWER spectra, *DARK matter, *GALACTIC redshift, *AXIONS, *ASTRONOMICAL perturbation, *QUASARS, UNIVERSE
Abstract

The evolution of cosmic perturbations in a two-component ultralight axionic universe is investigated. We present the first spectral computation of perturbations in multicomponent universes. A particular case composed of light extreme axions and free massive particles offers a possibility for the formation of very high-redshift massive galaxies, which are typically required to host massive early quasars. Our computation retains the information of perturbed velocities for individual axion components, opening a new avenue for setting up initial conditions for future axion dark matter simulations. [ABSTRACT FROM AUTHOR]

Published
2021
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36. Magnification Bias of Distant Galaxies in the Hubble Frontier Fields: Testing Wave Versus Particle Dark Matter Predictions.

Author

Enoch Leung, Tom Broadhurst, Jeremy Lim, Jose M. Diego, Tzihong Chiueh, Hsi-Yu Schive, and Rogier Windhorst

Subjects
MAGNIFICATION (Optics), GRAVITATIONAL lenses, GRAVITATIONAL effects, GALAXIES, LUMINOSITY
Abstract

Acting as powerful gravitational lenses, the strong lensing galaxy clusters of the deep Hubble Frontier Fields (HFF) program permit access to lower-luminosity galaxies lying at higher redshifts than hitherto possible. We analyzed the HFF to measure the volume density of Lyman-break galaxies at z > 4.75 by identifying a complete and reliable sample up to z ≃ 10. A marked deficit of such galaxies was uncovered in the highly magnified regions of the clusters relative to their outskirts, implying that the magnification of the sky area dominates over additional faint galaxies magnified above the flux limit. This negative magnification bias is consistent with a slow rollover at the faint end of the UV luminosity function and it indicates a preference for Bose–Einstein condensate dark matter with a light boson mass of over standard cold dark matter. We emphasize that measuring the magnification bias requires no correction for multiply-lensed images (with typically three or more images per source), whereas directly reconstructing the luminosity function will lead to an overestimate unless such images can be exhaustively matched up, especially at the faint end that is only accessible in the strongly lensed regions. In addition, we detected a distinctive downward transition in galaxy number density at z ≳ 8, which may be linked to the relatively late reionization reported by Planck. Our results suggests that JWST will likely peer into an “abyss” with essentially no galaxies detected in deep NIR imaging at z > 10. [ABSTRACT FROM AUTHOR]

Published
2018
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37. The Pan-STARRS1 Medium-deep Survey: Star Formation Quenching in Group and Cluster Environments.

Author

Hung-Yu Jian, Lihwai Lin, Kai-Yang Lin, Sebastien Foucaud, Chin-Wei Chen, Tzihong Chiueh, R. G. Bower, Shaun Cole, Wen-Ping Chen, W. S. Burgett, P. W. Draper, H. Flewelling, M. E. Huber, N. Kaiser, R.-P. Kudritzki, E. A. Magnier, N. Metcalfe, R. J. Wainscoat, and C. Waters

Subjects
STAR formation, STELLAR mass, GALAXY clusters, STELLAR density (Stellar population), QUENCHING (Chemistry)
Abstract

We make use of a catalog of 1600 Pan-STARRS1 groups produced by the probability friends-of-friends algorithm to explore how the galaxy properties, i.e., the specific star formation rate (SSFR) and quiescent fraction, depend on stellar mass and group-centric radius. The work is the extension of Lin et al. In this work, powered by a stacking technique plus a background subtraction for contamination removal, a finer correction and more precise results are obtained than in our previous work. We find that while the quiescent fraction increases with decreasing group-centric radius, the median SSFRs of star-forming galaxies in groups at fixed stellar mass drop slightly from the field toward the group center. This suggests that the main quenching process in groups is likely a fast mechanism. On the other hand, a reduction in SSFRs by ∼0.2 dex is seen inside clusters as opposed to the field galaxies. If the reduction is attributed to the slow quenching effect, the slow quenching process acts dominantly in clusters. In addition, we also examine the density–color relation, where the density is defined by using a sixth-nearest-neighbor approach. Comparing the quiescent fractions contributed from the density and radial effect, we find that the density effect dominates the massive group or cluster galaxies, and the radial effect becomes more effective in less massive galaxies. The results support mergers and/or starvation as the main quenching mechanisms in the group environment, while harassment and/or starvation dominate in clusters. [ABSTRACT FROM AUTHOR]

Published
2017
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38. GALAXY-SCALE GRAVITATIONAL LENS CANDIDATES FROM THE HYPER SUPRIME-CAM IMAGING SURVEY AND THE GALAXY AND MASS ASSEMBLY SPECTROSCOPIC SURVEY.

Author

James H. H. Chan, Tzihong Chiueh, Jean Coupon, Yutaka Komiyama, Satoshi Miyazaki, Atsushi J. Nishizawa, Paul Price, Philip J. Tait, Tsuyoshi Terai, Yousuke Utsumi, Bau-Ching Hsieh, Shiang-Yu Wang, Sherry H. Suyu, Anupreeta More, Hitoshi Murayama, and Masamune Oguri

Subjects
*GALAXIES, *SPECTRAL imaging, *GRAVITATIONAL lenses, *DARK matter
Abstract

We present a list of galaxy-scale lens candidates including a highly probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC) imaging survey. We combine HSC imaging with the blended-spectra catalog from the Galaxy And Mass Assembly (GAMA) survey to identify lens candidates, and use lens mass modeling to confirm the candidates. There are 45 matches between the HSC S14A_0b imaging data release and the GAMA catalog. We separate lens and lensed arcs using color information, and exclude those candidates with small image separations (<1.″0, estimated with the lens/source redshifts from the GAMA survey) that are not easily resolved with ground-based imaging. After excluding these, we find 10 probable lens systems. There is one system with an interacting galaxy pair, HSC J084928+000949, that has a valid mass model. We predict the total mass enclosed by the Einstein radius of ∼0.″72 (∼1.65 kpc) for this new expected lens system to be . Using the photometry in the grizy bands of the HSC survey and stellar population synthesis modeling with a Salpeter stellar initial mass function, we estimate the stellar mass within the Einstein radius to be . We thus find a dark matter mass fraction within the Einstein radius of . Further spectroscopy or high-resolution imaging would allow confirmation of the nature of these lens candidates. The particular system with the interacting galaxy pair, if confirmed, would provide an opportunity to study the interplay between dark matter and stars as galaxies build up through hierarchical mergers. [ABSTRACT FROM AUTHOR]

Published
2016
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39. CONTRASTING GALAXY FORMATION FROM QUANTUM WAVE DARK MATTER, ψDM, WITH ΛCDM, USING PLANCK AND HUBBLE DATA.

Author

Hsi-Yu Schive, Tzihong Chiueh, Tom Broadhurst, and Kuan-Wei Huang

Subjects
*GALAXY formation, *DARK matter, *STELLAR luminosity function, *DWARF galaxies, *OPTICAL depth (Astrophysics), *GALACTIC redshift, *COSMIC abundances
Abstract

The newly established luminosity functions (LFs) of high-z galaxies at 4 ≲ z ≲ 10 can provide a stringent check on dark matter models that aim to explain the core properties of dwarf galaxies. The cores of dwarf spheroidal galaxies are understood to be too large to be accounted for by free streaming of warm dark matter without overly suppressing the formation of such galaxies. Here we demonstrate with cosmological simulations that wave dark matter, , appropriate for light bosons such as axions, does not suffer from this problem, given a boson mass of (2σ). In this case, the halo mass function is suppressed below at a level that is consistent with the high-z LFs, while simultaneously generating the kiloparsec-scale cores in dwarf galaxies arising from the solitonic ground state in . We demonstrate that the reionization history in this scenario is consistent with the Thomson optical depth recently reported by Planck, assuming a reasonable ionizing photon production rate. We predict that the LF should turn over slowly around an intrinsic ultraviolet luminosity of at . We also show that for galaxies magnified in the Hubble Frontier Fields, predicts an order of magnitude fewer detections than cold dark matter at down to , allowing us to distinguish between these very different interpretations for the observed coldness of dark matter. [ABSTRACT FROM AUTHOR]

Published
2016
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40. Evolution of linear wave dark matter perturbations in the radiation-dominated era.

Author

Ui-Han Zhang and Tzihong Chiueh

Subjects
*ASTRONOMICAL perturbation, *DARK matter, *RADIATION
Abstract

Linear perturbations of the wave dark matter, or ψ dark matter (ψDM), of particle mass ~10-22 eV in the radiation-dominant era are analyzed, and the matter power spectrum at the photon-matter equality is obtained. We identify four phases of evolution for ψDM perturbations, where the dynamics can be vastly different from the counterparts of cold dark matter (CDM). While in late stages, after mass oscillation, long-wave ψDM perturbations are almost identical to CDM perturbations, some subtle differences remain. The differences are even greater with intermediate-to-short waves that bear no resemblance to those of CDM throughout the whole evolutionary history. The dissimilarity is due to quantum mechanical effects which lead to severe mode suppression. We also discuss the axion model with a cosine field potential. The power spectrum of axion models is generally almost identical to that of ψDM, but in the extreme case, when the initial axion angle is near the field potential top, this axion model predicts a power excess over a range of wave numbers and a higher spectral cutoff than ψDM, as if ψDM had a higher particle mass. [ABSTRACT FROM AUTHOR]

Published
2017
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41. Chitah: STRONG-GRAVITATIONAL-LENS HUNTER IN IMAGING SURVEYS.

Author

James H. H. Chan, Sherry H. Suyu, Tzihong Chiueh, Anupreeta More, Philip J. Marshall, Jean Coupon, Masamune Oguri, and Paul Price

Subjects
QUASARS, ROBOTICS, LENS antennas, IMAGE processing, GAUSSIAN beams
Abstract

Strong gravitationally lensed quasars provide powerful means to study galaxy evolution and cosmology. Current and upcoming imaging surveys will contain thousands of new lensed quasars, augmenting the existing sample by at least two orders of magnitude. To find such lens systems, we built a robot, Chitah, that hunts for lensed quasars by modeling the configuration of the multiple quasar images. Specifically, given an image of an object that might be a lensed quasar, Chitah first disentangles the light from the supposed lens galaxy and the light from the multiple quasar images based on color information. A simple rule is designed to categorize the given object as a potential four-image (quad) or two-image (double) lensed quasar system. The configuration of the identified quasar images is subsequently modeled to classify whether the object is a lensed quasar system. We test the performance of Chitah using simulated lens systems based on the Canada–France–Hawaii Telescope Legacy Survey. For bright quads with large image separations (with Einstein radius ) simulated using Gaussian point-spread functions, a high true-positive rate (TPR) of and a low false-positive rate of show that this is a promising approach to search for new lens systems. We obtain high TPR for lens systems with , so the performance of Chitah is set by the seeing. We further feed a known gravitational lens system, COSMOS 5921+0638, to Chitah, and demonstrate that Chitah is able to classify this real gravitational lens system successfully. Our newly built Chitah is omnivorous and can hunt in any ground-based imaging surveys. [ABSTRACT FROM AUTHOR]

Published
2015
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42. Soliton oscillations and revised constraints from Eridanus II of fuzzy dark matter.

Author

Chiang, Barry T., Hsi-Yu Schive, and Tzihong Chiueh

Subjects
*DARK matter, *OSCILLATIONS, *STAR clusters, *WAVE functions, *BOSONS
Abstract

Fuzzy dark matter (FDM) has been a promising alternative to standard cold dark matter. The model consists of ultralight bosons with mass mb∼10-22 eV and features a quantum-pressure-supported solitonic core that oscillates. In this work, we show that the soliton density oscillations persist even after significant tidal stripping of the outer halo. We report two intrinsic yet distinct timescales associated, respectively, with the ground-state soliton wave function τ00 and the soliton density oscillations τsoliton, obeying τsoliton/τ00≃2.3. The central star cluster (SC) in Eridanus II has a characteristic timescale τsoliton/τSC∼2-3 that deviates substantially from unity. As a result, we demonstrate, both analytically and numerically with three-dimensional self-consistent FDM simulations, that the gravitational heating of the SC owing to soliton density oscillations is negligible irrespective of mb. We also show that the subhalo mass function to form Eridanus II does not place a strong constraint on mb. These results are contrary to the previous findings by Marsh and Niemeyer (2019). [ABSTRACT FROM AUTHOR]

Published
2021
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43. Understanding the Core-Halo Relation of Quantum Wave Dark Matter from 3D Simulations.

Author

Hsi-Yu Schive, Ming-Hsuan Liao, Tak-Pong Woo, Shing-Kwong Wong, Tzihong Chiueh, Broadhurst, Tom, and Pauchy Hwang, W. Y.

Subjects
*DARK matter, *MISSING mass problem (Astronomy), *QUANTUM states, *QUANTUM theory, *QUASI bound states
Abstract

We examine the nonlinear structure of gravitationally collapsed objects that form in our simulations of wave like cold dark matter, described by the Schrdinger-Poisson (SP) equation with a particle mass ~ 10-22 eV. A distinct gravitationally self-bound solitonic core is found at the center of every halo, with a profile quite different from cores modeled in the warm or self-interacting dark matter scenarios. Furthermore, we show that each solitonic core is surrounded by an extended halo composed of large fluctuating dark matter granules which modulate the halo density on a scale comparable to the diameter of the solitonic core. The scaling symmetry of the SP equation and the uncertainty principle tightly relate the core mass to the halo specific energy, which, in the context of cosmological structure formation, leads to a simple scaling between core mass (Mc) and halo mass (Mh), Mc ∝ a-1/2 M1/3h, where a is the cosmic scale factor. We verify this scaling relation by (i) examining the internal structure of a statistical sample of virialized halos that form in our 3D cosmological simulations and by (ii) merging multiple solitons to create individual virialized objects. Sufficient simulation resolution is achieved by adaptive mesh refinement and graphic processing units acceleration. From this scaling relation, present dwarf satellite galaxies are predicted to have kiloparsec-sized cores and a minimum mass of ~ 108M☉, capable of solving the smallscale controversies in the cold dark matter model. Moreover, galaxies of 2 × 1012M☉ at z = 8 should have massive solitonic cores of ~ 2 × 109M☉ within ~60 pc. Such cores can provide a favorable local environment for funneling the gas that leads to the prompt formation of early stellar spheroids and quasars. [ABSTRACT FROM AUTHOR]

Published
2014
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44. Multiple Images and Flux Ratio Anomaly of Fuzzy Gravitational Lenses.

Author

Chan, James H. H., Hsi-Yu Schive, Shing-Kwong Wong, Tzihong Chiueh, and Broadhurst, Tom

Subjects
*DARK matter, *FLUX (Energy), *DE-Broglie waves, *GRAVITATIONAL lenses, *QUASARS
Abstract

Extremely light bosonic wave dark matter (ψDM) is an emerging dark matter candidate contesting the conventional cold dark matter paradigm and a model subject to intense scrutiny of late. This work for the first time reports testable salient features pertinent to gravitational lenses of ψDM halos. ψDM halos are distinctly filled with large-amplitude, small-scale density fluctuations with δρ/ρhalo∼1 in form of density granules. This halo yields ubiquitous flux ratio anomalies of a few tens of percent, as is typically found for lensed quasars, and may also produce rare hexad and octad images for sources located in well-defined caustic zones. We have found new critical features appearing in the highly demagnified lens center when the halo has sufficiently high surface density near a very compact massive core. [ABSTRACT FROM AUTHOR]

Published
2020
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45. Soliton solution for the central dark mass in 47-Tuc globular cluster and implications for the axiverse.

Author

Emami, Razieh, Broadhurst, Tom, Smoot, George, Tzihong Chiueh, and Hoang Nhan Luu

Subjects
*DWARF galaxies, *COMPACT objects (Astronomy), *GLOBULAR clusters, *SCALAR field theory, *GRAVITATIONAL potential, *DARK matter, *ELLIPTICAL galaxies
Abstract

We offer a standing wave explanation for the rising proper motions of stars at the center of the globular cluster 47-Tucanae, amounting to ≃0.44% of the total mass. We show that this can be explained as a solitonic core of dark matter composed of light bosons, m≥10-18 eV, corresponding to ≤0.27 pc, as an alternative to a single black hole (BH) or a concentration of stellar BH remnants proposed recently. This is particularly important because having a concentrated stellar BH remnant with the above radii is very challenging without the heavy core since the three-body encounters would prevent the BHs from being that concentrated. We propose that this core develops from dark matter captured in the deep gravitational potential of this globular cluster as it orbits the dark halo of our Galaxy. This boson may be evidence for a second light axion, additional to a lighter boson of 10-22 eV, favored for the dominant dark matter implied by the large dark cores of dwarf spheroidal galaxies. The identification of two such light bosonic mass scales favors the generic string theory prediction of a wide, discrete mass spectrum of axionic scalar fields. [ABSTRACT FROM AUTHOR]

Published
2020
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46. Recognizing Axionic Dark Matter by Compton and de Broglie Scale Modulation of Pulsar Timing.

Author

De Martino, Ivan, Broadhurst, Tom, Tye, S.-H. Henry, Tzihong Chiueh, Hsi-Yu Schive, and Lazkoz, Ruth

Subjects
*DARK matter, *DE-Broglie waves
Abstract

Light axionic dark matter, motivated by string theory, is increasingly favored for the "no weakly interacting massive particle era". Galaxy formation is suppressed below a Jeans scale of ≃108 M⊙ by setting the axion mass to mB∼10-22 eV, and the large dark cores of dwarf galaxies are explained as solitons on the de Broglie scale. This is persuasive, but detection of the inherent scalar field oscillation at the Compton frequency ωB=(2.5 months)-1(mB/10-22 eV) would be definitive. By evolving the coupled Schrödinger-Poisson equation for a Bose-Einstein condensate, we predict the dark matter is fully modulated by de Broglie interference, with a dense soliton core of size ≃150 pc, at the Galactic center. The oscillating field pressure induces general relativistic time dilation in proportion to the local dark matter density and pulsars within this dense core have detectably large timing residuals of ≃400 nsec/(mB/10-22 eV). This is encouraging as many new pulsars should be discovered near the Galactic center with planned radio surveys. More generally, over the whole Galaxy, differences in dark matter density between pairs of pulsars imprints a pairwise Galactocentric signature that can be distinguished from an isotropic gravitational wave background. [ABSTRACT FROM AUTHOR]

Published
2017
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47. Self-consistent construction of virialized wave dark matter halos.

Author

Shan-Chang Lin, Hsi-Yu Schive, Shing-Kwong Wong, and Tzihong Chiueh

Subjects
*PHYSICS periodicals, *SELF-consistent field theory, *SCHRODINGER equation
Abstract

Wave dark matter (ψDM), which satisfies the Schrödinger-Poisson equation, has recently attracted substantial attention as a possible dark matter candidate. Numerical simulations have, in the past, provided a powerful tool to explore this new territory of possibility. Despite their successes in revealing several key features of ψDM, further progress in simulations is limited, in that cosmological simulations so far can only address formation of halos below ~2×1011M⊚ and substantially more massive halos have become computationally very challenging to obtain. For this reason, the present work adopts a different approach in assessing massive halos by constructing wave-halo solutions directly from the wave distribution function. This approach bears certain similarities with the analytical construction of the particle-halo (cold dark matter model). Instead of many collisionless particles, one deals with one single wave that has many noninteracting eigenstates. The key ingredient in the wave-halo construction is the distribution function of the wave power, and we use several halos produced by structure formation simulations as templates to determine the wave distribution function. Among different models, we find the fermionic King model presents the best fits and we use it for our wave-halo construction. We have devised an iteration method for constructing the nonlinear halo and demonstrate its stability by three-dimensional simulations. A Milky Way-sized halo has also been constructed, and the inner halo is found to be flatter than the NFW profile. These wave-halos have small-scale interferences both in space and time producing time-dependent granules. While the spatial scale of granules varies little, the correlation time is found to increase with radius by 1 order of magnitude across the halo. [ABSTRACT FROM AUTHOR]

Published
2018
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