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Colloquium2014

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2014

Schedule & History

2010ǯ 2011ǯ 2012ǯ 2013ǯ

ȯɽȥ/
4/16Steven Rieder (Kapteyn Astronomical Institute)The Clustered Universe⥹ / 14:10
4/23 ()ʬұͤˤMHDߥ졼عּ / 14:10
5/7 ()ĶȯˤȤηв⥹ / 14:10
5/14 һ (CfCA)濴˵ѡεƻĹȾʬۤηʥꥪ⥹ / 14:10
5/21߷ (CfCA)Ķȯˤʪȼߺȿ⥹ / 14:10
5/28Ĺë ɧ (CfCA)ϱפˤȤŤshear԰βǽ⥹ / 14:10
6/4Ҳ ϲ ()Planetesimal Formation via Fluffy Dust Aggregates⥹ / 14:10
6/11ݻ ҹ ()츶оΥ˥塼ȥФȡư̰ܹԤˤȤʤŷθ⥹ / 14:10
6/18 (CfCA)֥åۡǤĬ˲ݤռήΡήΥߥ졼⥹ / 14:10
6/25 ŵ (ELSI)Collisions, Collisions, Collisions⥹ / 14:10
7/2 (KEK)How to distinguish large field Inflation models after BICEP2⥹ / 14:10
7/9 ̭ (Univ. of Denver)Herschel Planetary Nebula Survey (HerPlaNS)⥹ / 14:10
7/16ʡ л (NAOJ)Analytical computation of generalized Fermi-Dirac integrals by truncated Sommerfeld expansions⥹ / 14:10
7/23ƣ Ƿ (ELSI) SPH ˡ꼰Ȥα⥹ / 14:10
10/1ë ()¬Ⱦֵ / 14:10
10/8Ĺë ()Planet formation in inhomogeneous protoplanetary disksֵ / 14:10
10/15Turner, Edwin Lewis (Princeton Univ.)Tidally Heated ExoMoons (THEM): Theory, Observational Prospects & Astrobiological Possibilitiesֵ / 14:10
10/22ƣɧ (CfCA)ޥåϿνʿԾ׷ȤǤۻҤŻҤβ®ֵ / 14:10
10/24Keiichi Kodaira (JSPS Bonn Liaison Office)A Review: Conspiracy between dark-matter and matter in galaxy evolutionߥʡ(313漼) / 10:00׻
10/29Ͼ߰ (ELSI) ߥ졼õϱ¤ʬұֵ / 14:10
11/5Ralph Pudritz (McMaster) From Filaments to Stars: A New Paradigm for Star Formation祻ߥʡ / 16:00׻ò
11/13Kenneth C. Wong (ASIAA)Strong Gravitational Lensing as a Probe of Galaxy Evolution and Cosmologyֵ / 15:00
11/19Ali Rahmati (Univ of Zurich)Simulating the cosmic distribution of neutral hydrogen and its connection with galaxiesֵ / 14:10
11/26Ramon Brasser (ELSI)Tilting Saturn without tilting Jupiter: Constraints on giant planet migrationֵ / 14:10
12/03Nanase Harada(ASIAA)Molecules in Galactic Centersֵ / 14:10
12/12Felipe Alves (MPE)Magnetic fields in star-forming regions: from molecular clouds to coresALMA102 / 10:30׻
12/15Josep Miquel Girart (CSIC-IEEC)A decade of polarization observations with the Submillimeter Array: Magnetic fields in the earliest and last stages of stellar evolutionֵ / 14:00׻
12/17 û̩٥ѡ⥹ / 14:10
1/7ƣ͵ () ¤äŪåȤθֵ / 14:10
1/14Ĺ͵ ʸ ϷؤνŪˡθŸ˾ֵ / 14:10
1/28īͺա åȤǥߺѤˤʬұμήΥߥ졼ֵ / 14:10
2/4ʿͪ/ Origin of the r-process elements in galactic chemodynamical evolution model ֵ / 13:30
3/13ƣǷʹر ϱפξܺٹ¤¿Ĺ¬ֵ / 13:30׻
3/13Man Hoi Lee The University of Hong Kong The Puzzle of the Pluto Satellite Systemֵ / 15:00׻

Abstract

4/16 Steven Rieder(Kapteyn Astronomical Institute, Groningen) The Clustered Universe
In this seminar, I will discuss various simulations concerning gravity, applied to structure formation in the Universe (the CosmoGrid simulation) and to star clusters (with AMUSE). The first part concerns CosmoGrid, a high-resolution LambdaCDM simulation, which we ran in parallel over multiple supercomputers, including one in Japan and one in the Netherlands. With CosmoGrid, I study the formation and environment of dark matter haloes in voids. In the second part, I will discuss AMUSE, a framework that enables the combination of various simulation codes like gravitational dynamics and stellar evolution. I use it to perform simulations of star clusters within an evolving environment, such as a dark matter halo or a forming disk galaxy, and study their disruption as a function of environment.
4/23 (Ωŷʸ) ʬұͤˤMHDߥ졼
Ƕ˵ʬұδ¬顢ʬұι®ͤˤä嵯Ƥ뤳ȤƤ롣ܸǤϤΤ褦ʬұͤˤǽɤ򣳼μήΥߥ졼Ĵ٤ΤǤη̤롣
5/7 (Ωŷʸ) ĶȯˤȤηв
ĶϡˤȤμפʶ븻ȤƹͤƤꡢĶˤäֶ֤˶뤵Ȥ̤ϡ鸽ߤ˵ڤ֥Ȥεʲ餫ˤǽפʲǤ롣ֱܹǤϡޤ˵ĶĶijˤȷδ¬ŪˤĤƴñ˾Ҳ𤹤롣ˡĶХˤȤη׷ȤˤȤ˲⤷ֶ֤˶뤵ȤΥ̤׻̤ˤĤ𤹤롣äֱܹǤϡȯ˿dzؤII-PĶϡ0.01 umʾŪ礭Ȥ0.1-1.0ۼֶ̤֤ۤФͭϤʥȤζ븻Ǥ뤳Ȥ򼨤
5/14 һ(ΩŷʸCfCA) 濴˵ѡεƻĹȾʬۤηʥꥪ
¬줿ѡηϳ濴˵˶ĤǤʤƻȯƤ롣椫饬Ƿϵƻư򤹤뤳ȤΤƤ롣εƻưޤNη׻η̤ϡ濴˵˶ĵƻˤϤη򼨺ȯɽǤϡ濴˵ѡεƻʬۤ򡢶ĵƻˤϤϳŪʰ򸦵椹뤳ȤǡƻưޤΥʥꥪΤǤ롣
5/21 ߷(ΩŷʸCfCA) Ķȯˤʪȼߺȿ
Ķȯᥫ˥ϡʪξ˥塼ȥȿΨ ɤΥߥʪ̩ܤ˴طƤ롣ϡήΤΥʥߥľ ְϤ̩١٤Ф¸פΤߤʤ餺˥塼ȥ͢׻ɬ ʡֳ˻ҡҳˤפͿ˽פʥǡǤꡢ׷Ȥνͥ ˥塼ȥΤˤǮΨ礭ƶ롣ܸǤϡ˷׻ ҳˤޤѤơޤ̵뤵ƤڸǤˤ ˥塼ȥβǮȿȯʥߥͿƶˤĤĴ٤Τǡη ̤롣
5/28 Ĺëɧ(ΩŷʸCfCA) ϱפˤȤŤshear԰βǽ
ϱǤϡפƻ̤ؤΥȤ¤ˤäKelvin-Helmholtz԰ (KHI) ꡢؤν԰ (GI) ȯ˸롣 αפǤKHI˴ؤԸǤϡȤĹϹθƤʤä ȤĹ뤳Ȥˤä®٤Ѳ뤿ᡢȤĹϥȤ¤˱ƶ롣 ܸǤϡȤĹKHIȯβǽͿƶˤĤܤפǤKHI˴ؤԸǤϹθƤʤäȤĹθˤKHIȯβǽˤĤĴ٤ȯɽǤϡη̤ˤĤ𤹤롣
6/4 Ҳ ϲʹΩŷʸPlanetesimal Formation via Fluffy Dust Aggregates
ȤιĹϡʳȤƽפ̤Ǥ롣ܸǤϡȤιĹˤ̩ٿʲƳ뤳ȤŪ褹뤳Ȥܻؤפ㲹㰵ǤΤǥȤ˵ˤϤʤ餺ַʤĹ롣Τ褦ʥȤνΤȥꥲȤȸƤܸ֡ǤϡͤƤͤˤ밵̤¾ˡȥꥲȤŪ̲ƳޤϤθ¿ηϤοͷ׻ˤꡢŪ̶٤꼰˰̶٤ŬѤ̡ȤϰöΨä塢񹳰ϵڤӼʽϤˤäư̤졢뤳Ȥ狼äˤλˤǤä濴ꡦ˲ꡦķ֤Ǥ뤳Ȥ狼äʤܸʳǤȤιĹŪ˲ᤷǤ롣
6/11 ݻ ҹء˶츶оΥ˥塼ȥФȡư̰ܹԤˤȤʤŷθ
ĶȯѲȥ˥塼ȥФ϶ϢäƤ롣ơ˥塼ȥФȸμޤϢäƤ롣桹˶ʥޥͥˤ˾ơ¤˥塼ȥΤʪˤ뻶𡢵ۼѤŪʿѤƷ׻Υ˥塼ȥФΰ򡢵ˡη̤顢˥塼ȥиؤαư̰ܹԤ򳵻ѥ륵å礭ʥԥ®Ȥäŷθݤؤαƶ롣
6/18 ʹΩŷʸCfCA˵֥åۡǤĬ˲ݤռήΡήΥߥ졼
ǯ֥åۡǤĬ˲ݤȼΨ٤áåȤʮФܤ򽸤Ƥ롣ϳϤ濴 Swift J1644+57 Ǥ2011ǯ˵޷ꤽΥԡ٤ϥǥȥ٤1ܤȤʤäĬ˲줿ΥĶ׳ήȹͤƤ롣ŷΤǤ1ǯȾ˵޷ʸ¬ƤꡢĶ׳ήɸפؾܤǽ롣ǡռήΥߥ졼»ܤθɸפؤξܤˤ굯뤳ȤǧŷΤƤĶ׳ήؤܤǽˤĤƤ롣ޤ濴֥åۡSgr A*Ǥ⥬G2ܶᤷԤƤG2pericenter̲ȹͤƤ뤬Ȥƶ濴ǤǧƤʤG2ȹⲹήߺѤ3ήΥߥ졼»ܤ̤ȤˡG2ˤ뺣ǽˤĤƤ롣
6/25 ŵ ELSICollisions, Collisions, Collisions
ϡߥ󥵥ΥȤˤʤޤǤ͡ʵϤξͤиĹƤäơͥץ򤹤뤳Ȥ򤹤ǶˤƽפǤ롣ȯɽǤϡޤ򳵴Ѥǵͤ˴ؤƲ桹ǶԤäƤƱΤξͤ˴ؤ븦ȡŷξͤ˴ؤ븦Ҳ𤹤롣
7/2 ϡKEKHow to distinguish large field Inflation models after BICEP2
I would like to give a talk on a variety of large field inflation models which can fit the observational data recently-reported by BICEP2. Next I will discuss how to distinguish those models by using future cosmological 21cm fluctuation and CMB B-mode polarization observations. I will give a talk on a corresponding introduction of inflationary cosmology at the first half of my talk.
7/9 ̭ (Univ. of Denver) Herschel Planetary Nebula Survey (HerPlaNS)
ϡ뱧˾ϥ衼åѱ赡ءESAˤǾ夲ѤֳĹ3.5mȤ´¬ǽˤߥåǤ롣桹θ楰롼פǤϡϡιʬǽȸ꤬ˤֳ¤Ѥ11ĤΥ٥ԤΤ뵱ʬ⳰¦ΰǡ㲹ȤϢ³Υٹ¤ʬҥβžܵζʬۤĴ٤줿ǡ顢ȡΥʬҥ줾ζʬۤƳʬ򤷤Ȥμ¬Ū˵뤳ȤǡȤΤɤ餫¬ƥǥ뤹뤳ȤǤ⤦̤ȤŪ˹ԤƤˡθڤߤޤǽƤȤʬҥOH+ȯˤĤƤݡȤ롣
7/16 ʡ л (NAOJ) Analytical computation of generalized Fermi-Dirac integrals by truncated Sommerfeld expansions
For the generalized Fermi-Dirac integrals, $F_k(\eta,\beta)$, of orders $k=-$1/2, 1/2, 3/2, and 5/2, we explicitly obtained the first 11 terms of their Sommerfeld expansions. The main terms of the last three orders are rewritten so as to avoid the cancellation problem. If $\eta$ is not so small, say not less than 13.5, 12.0, 10.9, and 9.9 when $k=-1/2$, $1/2$, $3/2$, and $5/2$, respectively, the first 8 terms of the expansion assure the single precision accuracy for arbitrary value of $\beta$. Similarly, the 15-digits accuracy is achieved by the 11 terms expansion if $\eta$ is greater than 36.8, 31.6, 30.7, and 26.6 when $k=-1/2$, $1/2$, $3/2$, and $5/2$, respectively. Since the truncated expansions are analytically given in a closed form, their computational time is sufficiently small, say at most 4.9 and 6.7 times that of the integrand evaluation for the 8- and 11-terms expansions, respectively. When $\eta$ is larger than a certain threshold value as indicated, these appropriately-truncated Sommerfeld expansions provide a factor of 10-80 acceleration of the computation of the generalized Fermi-Dirac integrals when compared with the direct numerical quadrature.
7/23 ƣ Ƿ (ELSI) SPH ˡ꼰Ȥα
Smoothed Particle Hydrodynamics (SPH) ˡϰήΤοͲˡΰĤǤ롣饰󥸥ˡǤ뤿ᡢޤǶϷʤŷʸؤʬǹƤǯ SPH ˡǤϡܿϢ³̤򰷤ȤǤηή԰ʤ̤ФȤŦ줿(Agertz+2007 ʤ)θϡ SPH ˡǤϡ̩٤ʬǽꤷƤ뤫Ǥ롣ϤܿϢ³̤Ǥϡ̩٤Ϣ³Ѳ롣Τᡢ̩٤ʬǽꤷ꼰Ǥϡ̩ٿ˥顼ȯ줬ϸۤʤɤοȵڤ롣ϸۤΥ顼ʪŪɽĥϤȤƯή԰ȯã˳롣Dz桹ϡ̩٤˰ϤѤ SPH (Density Independent SPHʲDISPH)ˡ꼰ԤäϤѤ꼰ԤäƤ뤿ᡢܿϢ³̤ˤʪŪɽĥϤϸʤ켡׷ȴꡢ󼡸ſ尵ʿήꡢ󼡸ӥ=إۥĤӥ쥤꡼ƥ顼԰ꡢоȯʤɤɸŪʥƥȤΤ٤Ƥˤ DISPH Ͻ SPH ɤ̤򼨤DISPH ˡϽ SPH ˡѤ뿷ɸˤʤȴԤ롣ȯɽǤϡDISPH ˡ򤵤˰̲꼰䡢ϵʳؤʬؤαѤˤĤƤ⿨줿
10/1 ë () ¬Ⱦ
Ķȯ˻ĤϡϾǤϼ¸ʹ̩٤Ȥʤ١ϤΤ褦ʶ˸´ĶǤʪĴ٤乥μ¸ȸ롣ι¤ϡʪξˤäƷޤ뤬äϾθҳ˼¸븶ҳ˰¥ѥ᡼ϡ̾ɽնθؤǤ륯饹ΰ̤ξˤʪ̩ܤ˴Ϣ롣ǯޥͥȸƤФ붯θŷΤǤ𥬥ԡȯ줿Ūư濴ŷΤǤοưȶӤĤȹͤ롣ǡ桹ϤνŪư饹ΰǤ˵ȹͤҳ˰¥ѥ顼᡼¤Ϳߤǡ򵭽ҤΤɤҳ˥ѥ᡼ƳФˤΥѥ᡼Ѥơ¬ؤ¤ˤڤ롣
10/8 Ĺë () Planet formation in inhomogeneous protoplanetary disks
One of the most fundamental questions in theories of planet formation is how planets form out of protoplanetary disks. As shown by many previous studies, planetary migration, that arises from resonant, tidal interactions between protoplanets and the natal disks, jeopardizes the existence of any planetary system around the central stars. In this talk, I will present all the key results of my recent work, wherein planet traps - specific sites in protoplanetary disks at which planets undergoing rapid type I migration are captured - play a crucial role. We will discuss how disk inhomogeneities, one of the general properties of planetary disks, give rise to planet traps and how planet traps affect the formation and evolution of planetary systems. Comparisons with a large number of observed exoplanets enable us to verify our picture of planet formation based on planet traps.
10/15 Turner, Edwin Lewis (Princeton Univ.) Tidally Heated ExoMoons (THEM): Theory, Observational Prospects & Astrobiological Possibilities
Tidally heated exomoons (THEM) can plausibly be far more luminous than their host exoplanet and can shine brightly at arbitrarily large separations from the system's stellar primary with temperatures of several hundreds degrees Kelvin or higher. Furthermore, these temperatures can occur in systems that are billions of years old. THEM may thus be far easier targets for direct imaging studies than giant exoplanets, which must be both young and at a large projected separation for detection with current and near future facilities. If THEM exist and are sufficiently common, it may well be far easier to directly image an exomoon with surface conditions that allow the existence of liquid water than it will be to resolve an Earth-like planet in the classical Habitable Zone of its primary.
10/22 ƣ ɧ (CfCA) ޥåϿνʿԾ׷ȤǤۻҤŻҤβ®
֤ⲹǴʥץ饺ǤϡγҴ֤Υͤż줬طĸݤ ץ饺ޤΥʥߥ̵ۤͥץ饺ޤȸƤФ롣̵ͥץ饺Ť׷Ȥ̵;׷ȤȸƤФ졢ĶijСȤξ׷ȡưϤΥåȤʤɡΤޤޤʸݤտ路ȯȹͤƤ롣̵;׷ȤϹ⥨ͥ륮γҤȼȤ¿׷ȤˤγҲ®ƯƤȹͤƤ롣Ķijξ׷Ȥ kneeͥ륮(10^15eV)ޤǤαεȹͤƤ뤬¬뱧Υͥ륮ʬۤ褦ˡ׷ȤǤγҲ®Power-lawŪʥͥ륮ʬۤФȤǤ뵡Ǥ뤳ȤԤ롣Τ褦ʵȤƤϾ׷Ȥˤ1ե߲®ͭϤǤ롣ǯΥϥ֥åˡۻҤγҡŻҤήΤȤưߥ졼ˡˤѤߥ졼ˤꡢ׷ˡطʼθʿԤ˶ᤤʿԾ׷ȤˤơPower-law Υͥ륮ʬۤĹ⥨ͥ륮ۻҤФγҲ®ƯȤºݤ˼줿Sugiyama 2011ʤɡˡθǤϡŻҤγҤȤưPICߥ졼ˡѤơޥåϿ30٤ιޥåϿνʿԾ׷Ȥ1ߥ졼Ԥ׷Ȥη䤽ǵγҲ®ˤĤĴ٤η̡׷նDz®ƯۻҤ®졢Power-lawŪʥͥ륮ʬۤĹ⥨ͥ륮ۻҤ뤳ȤǧȤȤˡ̤ϾʤΤΰŻҤ®狼äֱǤϤη̤ˤĤ𤹤롣
10/24 Keiichi Kodaira (JSPS Bonn Liaison Office)A Review: Conspiracy between dark-matter and matter in galaxy evolution
Selected works are reviewed which are related to the unknown interaction ("conspiracy") between dark-matter and matter in galaxy evolution. Starting from 1970's when optical and radio observation yielded "luminosity- velocity relations" to the decades of 1990's-2000's when SDSS data and X-ray data became available, the accumulating data suggest that some kinds of unknown "physical processes" must be acting to make matching between the dark-matter halo and the global structures of the imbedded matter galaxy. $(Q#| Since the dark-matter halos and the galaxy stellar systems can be regarded as particle ensembles, the phase-space-density distributions might play an important role. Recent large scale simulations in the LCDM universe produced model universe following their evolution from high z through z=0. The behavior of the dark-matter halos without dissipative processes shows common characteristics, as are indicated in the simulations in the Millennium Project / the Aquarius Project. The trials to include dissipative processes among baryons leading to the formation of the observable galaxies involve complex physical-chemical processes like star formation & evolution, and AGN phenomena, including energy / momentum / chemical elements feed- backs, and, so far, they have to invoke some kind of empirical, phenomenological treatments, by adjusting the values of the assumed parameters so that the resulting abundance and relations match to the observed ones. Facing with the high complexity of the involved processes, one may be inclined to adopt a working hypothesis that the nature of the "conspiracy" might be a kind of systemic (collective) influence of the dark-matter halo upon the evolution of the baryon system imbedded in it.
10/29Ͼ߰ (ELSI) ߥ졼õϱ¤ʬұ
׶Ϥɽ̤¸ߤ뱲ӹ¤ΤϡɸŪˤϡ̩ȡפȤưݤǤȲᤵƤ(̩Ȳ)̩Ȳ1960 ǯLin & Shu ˤ󾧤졤 θλٻƤΤΡꤵƤꡤ¤αϤŬѤǤ뤫ϼǤϤʤ ޤǻϡʬǽNΡ¿֥ߥ졼Ԥơ ӹ¤ΥʥߥݻĴ٤Ƥ (Baba et al. 2009; Fujii, Baba et al. 2011; Baba et al. 2013) ä˥СΤʤ (multiple spiral) ܤϱӤ (1) ϲž˱褦ưžԤޤʤ顤 (2)ϲž٤λּ٤ǹΡʬˤưʥߥå¤Ǥꡤ (3) Ӥˤ껶𤵤줿ϥ२ͥ륮򤢤ޤ뤳Ȥʤ ¾Ⱦ¤˰ư (radial migration) 뤳ȤDZӤĹְݻ뤳Ȥʤɤ򼨤Ƥ ŷϤޤ¿αϤ濴¤(С)αӤΥʥߥͿ ƶ̵Ǥʤȹͤ롥 ܸǤϡʬǽNΡ¿֥ߥ졼ѤơϤιϱӤ ʥߥ֥ο񤤤Ĵ٤ η̡multiple spiralȤϰۤʤꡤСαƶDZӤ϶ϲž®®٤DzžΤΡ Ϻưžˤ괬ߤαƶʤʲ뤳Ȥ狼äޤСȥѥߺѤˤꥹѥ뤬200Myrμ˲򷫤֤Ȥݤ⸫줿ֱܹǤϤκǶ̤Ҳ𤹤롥ޤ֤СӤСΰˤʬұηʲ˴ؤ̤Ҳ𤹤롥
11/05 Ralph Pudritz (McMaster) From Filaments to Stars: A New Paradigm for Star Formation
Filamentary structure is ubiquitous on multiple scales in molecular clouds. Observations with the Herschel observatory indicate that it is closely connected with star formation. I will discuss some of the significant advances that have occurred in our understanding of the formation, structure, and evolution of filaments and their links with star formation. I will first address some basic ideas of the structure and stability of equilibrium models of filaments including the role of gravity, turbulence, and magnetic fields. Simulations of turbulent clouds emphasize the highly dynamical aspects of filament formation including accretion flows onto and along filaments, the creation of cluster forming regions at filament nodes, and the combination of dynamical fragmentation and filamentary flow that leads to the formation of individual stars and disks. Finally I'll review some of our recent results on how filamentary structure affects radiative feedback from massive stars and the formation of star clusters. Filaments, it appears, offer some important new insights on how star formation occurs and is controlled.
11/13 Kenneth C. Wong (ASIAA EACOA Fellow)Strong Gravitational Lensing as a Probe of Galaxy Evolution and Cosmology
Strong gravitational lens galaxies present a unique opportunity to study galaxy evolution and cosmology. By constructing a mass model of the lens galaxy that can reproduce the observed lensing configuration, it is possible to constrain the structural properties of the galaxy. Furthermore, lensed quasars with a measured time delay can be used to constrain cosmological parameters, independent of other probes such as supernovae, CMB observations, and BAOs. Most of the lens galaxies discovered to date have been at relatively low redshift (z~0.3) with very few discovered at z > 1. I present the discovery of a lens galaxy at z = 1.62, making it the most distant lens galaxy known. Analysis of this system shows that it is a compact early-type galaxy with an IMF more consistent with Chabrier than Salpeter, in contrast to results for similar galaxies at low redshift. I also present results from the H0LiCOW project, which aims to accurately model five time-delay lenses to get an accurate determination of the Hubble constant. In particular, correcting for biases introduced by line-of-sight structures projected near the lens galaxy is a key systematic that needs to be overcome. I present a new method for accurately and efficiently characterizing these effects, which accounts for the most significant perturbers explicitly while treating the majority of the perturbers with an approximation that greatly reduces the necessary computations.
11/19 Ali Rahmati (Univ of Zurich) Simulating the cosmic distribution of neutral hydrogen and its connection with galaxies
Modern state-of-the-art cosmological simulations of galaxy formation have become indispensable tools for probing the main processes that shape the formation and evolution of galaxies. Therefore, they can be used to learn about the cycle of gas in galactic ecosystems. In this context, I will talk about the distribution of neutral hydrogen and metal absorbers in cosmological simulations and the physical conditions they are representing. In addition to comparing the predictions from simulations with observations, I will discuss the inferences we can obtain from cosmological simulations to better understand the distribution of gas in and around galaxies.
11/26 Ramon Brasser (ELSI) Tilting Saturn without tilting Jupiter: Constraints on giant planet migration
The migration and encounter histories of the giant planets in our Solar System can be constrained by the obliquities of Jupiter and Saturn. We have performed many N-body simulations of the evolution of the outer Solar System containing the giant planets and a disc of planetesimals to study the expected final obliquity distribution of the gas giants. The initial conditions resembled those of the smooth migration model of Hahn & Malhotra, the resonant Nice model or Morbidelli et al. and two models with five giant planets in resonance initially. We find that all models have a similar probability to reproduce the current orbital properties of the giant planets while only two of these are able to reproduce the current obliquities of the gas giants, though with a small probability.
12/03 Nanase Harada(ASIAA) Molecules in Galactic Centers
Composition of different molecular species has been used to determine physical conditions of molecular gas in many of galactic star-forming regions. Recently, the early science of ALMA has shown the ability to observe molecular lines of variety of species even in extragalatic sources. In galactic centers, molecular abundances can be affected by X-rays from active galactic nuclei (AGNs), UV-photons from nuclear starbursts, cosmic rays from supernovae, or shock waves from outflows. In this talk, I will discuss how molecular abundances of different species in an AGN-containing galaxy can be affected by different mechanisms according to the chemical models. Next, I will move onto the circumnuclear disk at the center of Milky Way within a few-parsec from the central black hole Sgr A*. By combining chemical models and line surveys taken by IRAM 30-meter telescope and APEX telescope, I will present how energetic particles such as cosmic rays in the Galactic Center can affect the chemical compositions.
12/12 Felipe Alves (MPE) Magnetic fields in star-forming regions: from molecular clouds to cores
Magnetic fields affect the dynamics of the interstellar medium across awide range of physical scales. Large-scale magnetic fields in molecular clouds, filaments and Infrared Dark Clouds are crucial ingredients on the formation of low- and high-mass star-forming regions. In this talk, I will present recent results of multi-wavelength polarimetric observations of molecular clouds and cores. Most of this research was performed toward the Pipe nebula, a suitable laboratory for early star-formation studies. Our studies reveal that starless cores have a polarimetric regime affected by the absence of internal heating, which is predicted by models of dust grain alignment. The multi-wavelength data resolves the magnetic field structure toward both starless cores and their halos, and they reveal the dynamical state of the cloud through the structure function of the position angles and the B-field strength estimations. Complementary science obtained with molecular line data reveal the chemistry and kinematics of the Pipe cores and are tentatively combined with the polarization. Ongoing and future projects focused on SMA and ALMA will be also discussed.
12/15 Josep Miquel Girart (CSIC-IEEC) A decade of polarization observations with the Submillimeter Array: Magnetic fields in the earliest and last stages of stellar evolution
The magnetic field appears to be an essential ingredient in the star formation process. The dynamical evolution of the molecular clouds, including the formation of the filamentary structures and of the dense cores is thought to be controlled by magnetic fields and interstellar MHD turbulence. During the gravitational collapse of the dense cores, the influence of magnetic fields will determine the fragmentation level and how and when protoplanetary disks are formed around these stars. The magnetic fields also appears to play an essential role in the launching mechanism of jets. Moreover, during their last stages of evolution, stars with < 8 Msun show structures and physical processes that strongly resembles those of young stellar objects: high-velocity jets, tori/disks, all surrounded by a thick circumstellar envelope, which indicate that magnetic fields also play a important at these stages. In this talk, I will review the contribution of the polarimetric SMA observations in the study of magnetic fields in these processes.
12/17 ()û̩٥ѡ桡
ǯα˾ˤϳ٥ˤäơ ƻ100ʲǤϡ۷Ϥˤ¸ߤʤ֥ѡ ȤŷΤ̵¸ߤ뤳Ȥ餫ˤʤääˡϵ巿 ٤ƥХ륯̩٤㤤ѡ̩٥ѡˤ ȯϡˤȤäƽפǤ롣ֱܹǤϡ̩ ѡε˴ؤ桹ΥǥҲ𤷡θƤ 롣ޤ¬Ūڤ˴ؤ桹λߤˤĤƤҲ𤹤롣
1/7ƣ͵ () ¤äŪåȤθ
СȤ͵ǥȤƶǯͭ˾뤵ƤΤˡȸͥǥɤ롣ΥǥϡŻҤȤλˤä åȤƤҡʥˤåȤĥȼ٤ˤäƲ뤳Ȥˤäơʸ͡ˡ СȤȤʥꥪǤ롣ͤΤɾ뤿ˤϡҤå¤ޤǤΰϢβɤɬפ 뤿ᡢռ͢׻ɬܤȤʤ롣Τ褦ʷ׻ϡޤطήΤȤƥåȤʵоΤήΤѤΤۤ ɤǤ롣ΰǡήΥߥ졼˴Ť椫ϡåȤˤϾ׷Ȥ®٥ʤɤʣʹ¤Ū¸ߤ Ƥ롣¤ϸҤ͢¿ʱƶͿ뤿ᡢͤؤαƶ̵Ǥʤ ǡܸǤϥ= ˡѤռ͢׻ɤѤơʣʹ¤ȼäåȤͤŪɾä˥åȤع¤ȤʤäƤ ˤĤܤ׻Ԥäη̡ع¤äå¤ҤϡǮŪڥȥСȤΥڥȥ ƸǤ򼨤ޤΤ褦ʲˤä줿ͤϡиȼ餫ˤֱܹǤϤη̤ȶˡ ԤäƤ뻰ήΥߥ졼˴ŤͤθˤĤƤҲ𤹤ͽǤ롣
1/14 Ĺ͵ ʸ˶ϷؤνŪˡθŸ˾
ϷʣǤꡢñΥץǤϤϰŪˤʤ롣 ʣμϡ䥬ǮήϳŪʿʤɡϥ ٤ƶü˾ʪܼŪ˽פˤʤ뤿ǤꡢǤ ɤΤ褦ʷ׻Ѥ褦ȤǥƳԲķǤ롣桹ϡֵ ֥ƥ륤ˤޥη׻ˡʪȤ߹ ϡAGNνŪǥۤƤֱܹǤϡ ξǽä絬ϴ¬٥ȤδؤˤĤƾҲ𤹤롣
1/28 īͺա˥åȤǥߺѤˤʬұμήΥߥ졼
ưϳˤޥǴ¬뱧襸åȤ濴ŷζ˵Dz줿ͥ륮ޤ֥ߺѤ뤳ȤǼϤδĶ礭ʱƶͿ롣ܸǤϥåȤ֥ߺѤˤʬұη餫ˤ뤿ˡ֥Ѳθήη׻»ܤη׻Ϸ⥸åŷSS433ΥåȤαŤʬұWesterlund 2˴¬줿ʬұϷ濴ΰֳ¬ȯ줿Ť餻տ路ʬұŬѤåȤξ׷Ȥˤäư̤줿(HI)̩äˤΨξ徺ˤäѤ졢åȤ㲹̩٤ΰΤ褦ΰʬҥǽ롣㲹̩٥ư®٤Ͽkm/sˤʤ¬®٤뤳ȤǤ롣ޤHI̩ʬۤåȤι¤ʬұηͿƶĴ١HIΥե󥰥եˤäơ㲹̩ΰ褬Westerlund 2ʬҥιäʬۤ߸̾ʬۤƸǤ뤳Ȥ򼨤Ť餻ŬѤ׻ǤϡϷϤβžμžHIȥåȤߺѤĴ١ž®٤λ®ٺĹ̩٥뤳Ȥ򼨤
2/04 ʿͪ/Origin of the r-process elements in galactic chemodynamical evolution model
Astrophysical site(s) of r-process has not been identified yet. Promising site(s) of r- process are core-collapse supernovae (CCSNe) and neutron-star mergers (NSMs). Recent hydrodynamical simulations have shown that r-process elements heavier than 110 of mass number are difficult to synthesize by CCSNe. On the other hand, several studies reported that NSMs can synthesize these elements due to their environment of low electron fraction. Chemical evolution studies of the Milky Way (MW) halo without dynamical evolution have, however, shown that NSMs are difficult to reproduce observed r-process abundance ratio, such as [Eu/Fe] of metal-poor stars due to their low rate (~10^{-6}-10^{-3}/yr for a MW size galaxy) and long delay time (>~ 100 Myr). In this talk, we performed a series of simulations using an N-body/smoothed particle hydrodynamics (SPH) code, ASURA. We have constructed detailed chemo-dynamical evolution model of dSphs assuming NSMs are a major site of r-process. Our models successfully reproduce observed [Eu/Fe] by NSMs with delay time of 100 Myr as well as chemo-dynamical properties of observed local group dwarf spheroidal galaxies (dSphs) such as time variation of star formation rates, metallicity distribution, and mass-metallicity relation. We find that metal mixing in star-forming region is important physical process to reproduce [Eu/Fe] of metal-poor stars in dSphs. In addition, we find star formation rate in early epoch (< 1 Gyr) of galaxy evolution needs to be 10^{-4} Msun/yr. The minimum delay time of NSMs and the Galactic NSM rate are constrained to be < 500 Myr and ~10^{-4}/yr. This study strongly supports that NSMs can be the major site of r-process.
3/13 ƣǷʹر˸ϱפξܺٹ¤¿Ĺ¬
Ф˾ALMA˾ˤꡢֳ䥵֥ߥȤΰˤƸϱפŪʬ򤷤ƴ¬뤳ȤǽˤʤäƤη̡оΤʹ¤򸫤Τ顢Τ礭ʥǤоΤΡ꾮ʥǤξܺ٤ʹ¤Τʤɡ͡ʹ¤äϱפ¸ߤ뤳ȤʬäƤֱܹǤϡϱפοʹ¤δ¬顢פʪ֤ˤĤƤɤΤ褦ʤȤΤȤȤ롣äˡоHD 142527μϤθϱפι¤˴ؤǥ󥰤η̤䡢ֳλǮͤδ¬ˤƸ륹ѥ빽¤ˤĤƾҲ𤹤롣ˡפνߺѤη̤ȤƸ륮å׹¤䥹ѥ빽¤ˤĤƵδ¬ǤɤΤ褦ʤȤԤ뤫롣
3/13 Man Hoi LeeThe University of Hong KongThe Puzzle of the Pluto Satellite System
The dwarf planet Pluto has a fascinating satellite system with five known members: Charon, Styx, Nix, Keberos, and Hydra. The innermostsatellite Charon is about 1/8 as massive as Pluto, and the Pluto-Charon system is in a dual synchronous state, which is the endpoint of tidal evolution. The orbits of the four small satellites are nearly circular and coplanar with Charon's orbit, with orbital periods nearly in the ratios 1:3:4:5:6. These properties suggest that the small satellites were debris from the same impact event that placed Charon in orbit and had been pushed to their current positions by being locked in orbital resonances with Charon as Charon's orbit was expanded by tidal interactions with Pluto. I will discuss the tidal evolution of Pluto-Charon and show that the placing of the small satellites at their current orbital positions by resonant transport is unlikely. I will also discuss some alternative scenarios for the origin of the small satellites.