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Driving factors behind multiple populations

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Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 172-181页

作者： Ruoyun Huang Baitian Tang Chengyuan Li Doug Geisler Mario Mateo Ying-Yi Song Holger Baumgardt Julio A.Carballo-Bello Yue Wang Jundan Nie Bruno Dias JoséG.Fernández-Trincado School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China departamento de Astronomía Universidad de ConcepcionConcepcionChile instituto de Investigación Multidisciplinario en Ciencia y Tecnología Universidad de La SerenaLa SerenaChile departamento de Astronomía Facultad de CienciasUniversidad de La SerenaChile department of Astronomy University of MichiganAnn Arbor 48109USA David A.Dunlap department of Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada Dunlap Institute for Astronomy&Astrophysics University of TorontoToronto ON M5S 3H4Canada School of Mathematics and Physics The University of QueenslandSt.Lucia QLD 4072Australia instituto de Alta Investigación Universidad de TarapacáAricaChile CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China instituto de astrofísica Departamento de Ciencias FísicasFacultad de Ciencias ExactasUniversidad Andres BelloSantiagoChile instituto de Astronomía Universidad Católica del NorteAntofagastaChile

Star clusters were historically considered simple stellar populations,with all stars sharing the same age and initial chemical ***,the presence of chemical anomalies in globular clusters(GCs),called multiple stellar populations(MPs),has challenged star formation theories in dense *** studies show that mass,metallicity,and age are likely controlling parameters for the manifestation of *** the limit between clusters with/without MPs in physical parameter space is crucial to reveal the driving mechanism behind their *** this study,we look for MP signals in Whiting 1,which is traditionally considered a young *** the Magellan telescope,we obtained low-resolution spectra withinλλ=3850-5500?for eight giants of Whiting *** measured the C and N abundances from the CN and CH spectral indices.C and N abundances have variations comparable with their measurement errors(~0.1 dex),suggesting that MPs are absent from Whiting *** these findings with literature studies,we propose a limit in the metallicity *** compactness index parameter space,which relatively clearly separates star clusters with/without MPs(GCs/open clusters).This limit is physically *** a larger scale,the galactic environment determines cluster compactness and metallicity,leading to metal-rich,diffuse,old clusters formed ex *** proposed limit also impacts our understanding of the formation of the Sagittarius dwarf galaxy:star clusters formed after the first starburst(age≤8-10 Gyr).These clusters are simple stellar populations because the enriched galactic environment is no longer suitable for MP formation.

关键词： stellar galactic galaxy

Advanced strategies for marine antifouling based on nanomaterial-enhanced functional PDMS coatings

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Nano Materials Science 2024年第4期6卷 375-395页

作者： Xiaohui Shi Hao Wei Wenjun Zhou Paul E.D.Soto Rodriguez Cunguo Lin Lei Wang Zhijia Zhang School of Materials Science and Chemical Engineering Harbin Engineering University Qingdao Innovation and development Center of Harbin Engineering University State Key Laboratory for Marin Corrosion and Protection Luoyang Ship Material Research Institute (LSMRI) instituto de Estudios Avanzados IUdeA Departamento de Física Universidad de La Laguna C/Astrofísico Francisco Sanchez School of Chemistry and Chemical Engineering Harbin Institute of Technology

Marine biofouling seriously affects human marine exploitation and transportation activities, to which marine antifouling(AF) coatings are considered to be the most cost-effective solution. Since the mid-20th century, human beings have dedicated their efforts on developing AF coatings with long cycle and high performance, leading to a large number of non-target organisms? distortion, death and marine environmental pollution. Polydimethylsiloxane(PDMS), is considered as one of the representative environment-friendly AF materials thanks to its non-toxic, hydrophobic, low surface energy and AF properties. However, PDMS AF coatings are prone to mechanical damage, weak adhesion strength to substrate, and poor static AF effect, which seriously restrict their use in the ocean. The rapid development of various nanomaterials provides an opportunity to enhance and improve the mechanical properties and antifouling properties of PDMS coating by embedding *** on our research background and the problems faced in our laboratory, this article presents an overview of the current progress in the fields of PDMS composite coatings enhanced by different nanomaterials, with the discussion focused on the advantages and main bottlenecks currently encountered in this field. Finally, we propose an outlook, hoping to provide fundamental guidance for the development of marine AF field.

关键词： Nanomaterials Antifouling PDMS composites Environment-friendly Marine biofouling

On the non-evolution of the dependence of black hole masses on bolometric luminosities for QSOs

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Research in Astronomy and Astrophysics 2012年第3期12卷 249-259页

作者： Martín López-Corredoira Carlos M. Gutirrez instituto de astrofísica de Canarias departamento de astrofísica Universidad de La Laguna

There are extremely luminous quasi stellar objects （QSOs） at high redshift which are absent at low redshift. The lower luminosities at low redshifts can be understood as the external manifestation of either a lower Eddington ratio or a lower mass. To distinguish between both effects, we determine the possible dependence of masses and Eddington ratios of QSOs with a fixed luminosity as a function of redshifts; this avoids the Malmquist bias or any other selection effect. For the masses and Eddington ratios derived for a sample of QSOs in the Sloan Digital Sky Survey, we model their evolution by a double linear fit separating the dependence on redshifts and luminosities. The validity of the fits and possible systematic effects were tested by the use of different estimators of masses or bolometric luminosities, and possible intergalactic extinction effects. The results do not show any significant evolution of black hole masses or Eddington ratios for equal luminosity QSOs. The black hole mass only depends on the bolometric luminosity without significant dependence on the redshift as （M BH/10 9 M ）≈ 3.4 （L bol/10 47 erg s-1）0.65 on average for z ≤ 5. This must not be confused with the possible evolution in the formation of black holes in QSOs. The variations of the environment might influence the formation of the black holes but not their subsequent accretion. It also leaves a question to be solved： Why are there not QSOs with very high mass at low redshift？ A brief discussion of the possible reasons for this is tentatively pointed out.

关键词： accretion—methods: statistical—quasars: general

Confirmation of a Sub-Saturn-size Transiting Exoplanet Orbiting a G Dwarf:TOI-1194 b and a Very Low Mass Companion Star: TOI-1251 B from TESS

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Research in Astronomy and Astrophysics 2024年第3期24卷 129-143页

作者： Jia-Qi Wang Xiao-Jun Jiang Jie Zheng Hanna Kellermann Arno Riffeser Liang Wang Karen A.Collins Allyson Bieryla Lars A.Buchhave Steve B.Howell Elise Furlan Eric Girardin Joao Gregorio Eric Jensen Felipe Murgas Mesut Yilmaz Sam Quinn Xing Gao Ruo-Yu Zhou Frank Grupp Hui-Juan Wang CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy Of SciencesBeijing 10010China University of Chinese Academy of Sciences Beijing 100049China University Observatory Munich Scheinertrsse 1.D-81679 MunichGemany Max Planck Institute for Extraterrestrial Physics Giessenbachstr.1D-85748 GarchingGermany National Astronomical Observatories/Nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China Center for Astrophysics Harvard&Smithsonian60 Garden Street.CambridgeMA 02138USA National Space Institute Technical University of DenmarkElektrovejDK-2800 KgsLyngbyDenmark NASA Ames Research Center Moffett FieldCA 94035USA NASA Exoplanet Science Institute Caltech/IPACMail Code 100-221200 E.California Blvd.PasadenaCA91125USA Grand Pra Observatory Switzerland department of Physics Washington UniversitySt.LouisMO 63130.USA department of Physics and Astronomy Swarthmore CollegeSwarthmorePA 19081USA instituto de astrofísica de Canarias(IAC) E-38205 La Laguna.TenerifeSpain departamento de astrofísica Universidad de La LagunaSpain dept.of Astronomy and Space Sciences Ankara UniversityTandogan 06100AnkaraTurkey Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Urumqi No.1 Senior High School Urumqi 830002China Lijiang Gemini Observatory Lijiang 674199China

We report the confirmation of a sub-Saturn-size exoplanet,TOI-1194 b,with a mass of about 0.456+0.055-0.051M_(J),and a very low mass companion star with a mass of about 96.5±1.5 MJ,TOI-1251 *** candidates provided by the Transiting Exoplanet Survey Satellite(TESS)are suitable for further follow-up observations by ground-based telescopes with small and medium *** analysis is performed based on data from several telescopes worldwide,including telescopes in the Sino-German multiband photometric campaign,which aimed at confirming TESS Objects of Interest(TOIs)using ground-based small-aperture and medium-aperture telescopes,especially for long-period ***-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric *** measure an orbital period of 2.310644±0.000001 days,the radius is 0.767+0.045-0.041RJ and the amplitude of the RV curve is 69.4_(-7.3)^(+7.9)m s^(-1).TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data,whose orbital period is 5.963054+0.000002-0.000001days,radius is 0.947+0.035-0.033 R_(J) and amplitude of the RV curve is 9849_(-40)^(+42)ms^(-1).

关键词： planets and satellites fundamental parameters-planets and satellites gaseous planets-stars fundamental parameters-stars low-mass-methods data analysis-techniques photometric-techniques spectroscopic

New lepton non-universal forces in flavor physics?

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Science Bulletin 2022年第1期67卷 1-4,M0003页

作者： Jorge Martin Camalich Mitesh Patel instituto de astrofísica de Canarias Calle Via Lactea S-NTenerife 38200Spain departamento de astrofísica Universidad de La LagunaTenerife 38205Spain Imperial College London London SW72AZUK

The Standard Model(SM)of particle physics succeeds in predicting the vast majority of experimental high-energy data in terms of a minimal set of subatomic particles and their strong and electroweak ***,while it is a s... 详细信息

关键词： theory interactions predicting

Past,present and future of the Resonant-Mass gravitational wave detectors

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Research in Astronomy and Astrophysics 2011年第1期11卷 1-42页

作者： Odylio denys Aguiar instituto Nacional de Pesquisas Espaciais Divisao de Astrofísica Av. dos Astronautas 1758 So José dos Campos 12227-010 SP Brazil

Resonant-mass gravitational wave detectors are reviewed from the concept of gravitational waves and its mathematical derivation, using Einstein＇s general relativity, to the present status of bars and spherical detectors, and their prospects for the future, which include dual detectors and spheres with non-resonant transducers. The review not only covers technical aspects of detectors and sciences that will be done, but also analyzes the subject in a historical perspective, covering the various detection efforts over four decades, starting from Weber＇s pioneering work.

关键词： gravitation -- gravitational waves -- instrumentation: detectors

Quantum Instability of Magnetized Stellar Objects

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Chinese Journal of Astronomy and Astrophysics 2005年第4期5卷 399-411页

作者： R.González Felipe H.J.Mosquera Cuesta A.Pérez Martínez H.Pérez Rojas departamento de Física and Centro de Física Teórica de Partículas Instituto Superior TécnicoAv.Rovisco Pais1049-001 LisboaPortugal instituto de Cosmologia Relatividade e Astrofísica(ICRA-BR)Centre Brasileiro de Pesquisas FísicasRua Dr.Xavier Sigaud 150CEP 22290-180UreaRio de JaneiroRJBrazil Centro Latino-Americano de Física Avenida Wenceslau Braz 71CEP 22290-140 fundosBotafogoRio de JaneiroBrazil instituto de Cibernética Matemática y FísicaCalle E No.30910400 La HabanaCuba

The equations of state for degenerate electron and neutron gases are studied in the presence of magnetic *** including quantum effects in the investigation of the structural properties of these systems,it is found that some hypermagnetized stars can be unstable according to the criterion of stability of *** magnetized white dwarfs should collapse producing a supernova type Ia,while superstrong magnetized neutron stars cannot stand their own magnetic field and must implode,too.A comparison of our results with a set of the available observational data of some compact stars is also presented,and the agreement between this theory and observations is verified.

关键词： dense matter-equation of state-instabilities-stars:magnetic fields-stars:neutron white dwarfs

Solar-stellar astrophysics and dark matter

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Research in Astronomy and Astrophysics 2012年第8期12卷 1107-1138页

作者： Sylvaine Turck-Chize Ilídio Lopes CEA/IRFU/Service d'Astrophysique AIMCE Saclay91191 Gif sur YvetteFrance Centro Multidisciplinar de astrofísica Instituto Superior TcnicoUniversidade Tcnica de LisboaAv.Rovisco Pais1049-001 LisboaPortugal departamento de Física Escola de Ciência e TecnologiaUniversidade de vora Colgio Luis António Verney7002-554 voraPortugal

In this review, we recall how stars contribute to the search for dark matter and the specific role of the Sun. We describe a more complete picture of the solar interior that emerges from neutrino detections, gravity and acoustic mode measurements of the Solar and Heliospheric Observatory （SOHO） satellite, becoming a reference for the most common stars in the Universe. The Sun is a unique star in that we can observe directly the effect of dark matter. The absence of a signature related to Weakly Interacting Massive Particles （WIMPs） in its core disfavors a WIMP mass range below 12 GeV. We give arguments to continue this search on the Sun and other promising cases. We also examine another dark matter candidate, the sterile neutrino, and infer the limitations of the classical structural equations. Open questions on the young Sun, when planets formed, and on its present internal dynamics are finally dis- cussed. Future directions are proposed for the next decade： a better description of the solar core, a generalization to stars coming from seismic missions and a better under- standing of the dynamics of our galaxy which are all crucial keys for understanding dark matter.

关键词： stellar evolution: theory -- elementary particles -- helioseismology --dark matter -- early solar-planet relationship

Fiber laser with simultaneous multi-wavelength Er/Yb passively Q-switched and single-wavelength Tm gain-switched operations

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Photonics Research 2019年第6期7卷 608-614页

作者： J.ALANIZ-BAYLON M.DURAN-SANCHEZ R.I.ALVAREZ-TAMAYO B.POSADA-RAMIREZ M.BELLO-JIMENEZ B.IBARRA-ESCAMILLA A.A.CASTILLO-GUZMAN E.A.KUZIN instituto Nacional de astrofísica óptica y Electrónica (INAOE)L. E. Erro 1 Sta. Ma. Tonantzintla Pue. 72824 Mexico CONACyT-instituto Nacional de astrofísica óptica y ElectrónicaA. P. 51 y 216 Pue. 72000 Mexico CONACyT-Universidad Autónoma de Nuevo León Av.Universidad S/NSan Nicolas de los Garza N. L. 66451 Mexico instituto de Investigación en Comunicación óptica Universidad Autónoma de San Luis Potosí Av. Karakorum 1470 S. L. P. 78210 Mexico Universidad Autónoma de Nuevo León Av.Universidad S/NSan Nicolas de los Garza N. L. 66451 Mexico

We report the experimental investigation of an all-fiber multi-wavelength passively Q-switched Er/Yb laser with simultaneous gain-switched pulsed operation by using a thulium-doped fiber as a saturable *** emission is obtained in three wavelength regions with central peaks at around 1546 nm, 1561 nm, and1862 nm. Multi-wavelength emission with separation of approximately 1 nm is obtained around the wavelength regions of 1546 nm and 1561 nm. Stable laser pulses are generated in the pump power range from 3.6 W to7.3 W.

关键词： Fiber laser multi-wavelength