Download - Star Formation in Galaxies
Star Formation in GalaxiesStar Formation in Galaxies
Yuexing Li (Columbia Univ. /AMNH)
Mordecai Mac low (AMNH/Columbia)
Ralf Klessen (AIP, Germany)John Dubinski (CITA)
Zoltan Haiman (Columbia)
NASA, Hubble Heritage Team, Nick Scoville and T. Rector
Star Forming GalaxiesStar Forming Galaxies
NASA/STScI/B.Whitmore
1. Global Schmidt Law1. Global Schmidt Law
Kennicutt1998 Gao & Solomon 2004
2. Star Formation Thresholds2. Star Formation Thresholds
Martin & Kennicutt (2001)
Models of the SF lawsModels of the SF laws
Gravitational instability (Kennicutt89, Friedli et al. 94, Kennicutt98, Martin & Kennicutt 01)
Kinematical law (Wyse 86, Silk 87, Hunter, Elmegreen & Baker 98)
Density PDF from turbulence (Elmegreen 02, Kravtsov03, Krumholtz & McKee 05)
P1: SF in Isolated Disks P1: SF in Isolated Disks
Code: GADGET v1.1 (Springel, Yoshida & White 01)
+ sink particles (gravitationally bound, convergent flow, n >103 cm-3, represent star clusters)
Galaxy model: DM halo + disk (stars & isothermal gas)
(Mo, Mao, White 98, Springel & White 99, Springel 00) Initial conditions:
– rotational vel.: 50 ≤ Vrot ≤ 220 km s-1
– gas fractions: 20 ≤ fg ≤ 90% of Md– effective sound speed cg = 6, 15 km s -1
Numerical CriteriaNumerical Criteria
Jeans criterion for mass resolution (Bate & Burkert 97, Truelove et al. 97)
Gravity-hydro balance criterion for gravitational softening length (Bate & Burkert 97)
Equipartition criterion between gas, collisionless particle masses (Steinmetz & White 97)
Resolution StudyResolution Study
105
6.4 x 106106
8 x105
Li, Mac Low & Klessen 2005a
How Do Stars Form?How Do Stars Form?
LMK 2005b
Star Formation MorphologyStar Formation Morphology
Global Schmidt LawGlobal Schmidt Law
Kennicutt 1998
LMK 2005c
Local Schmidt LawsLocal Schmidt Laws
LMK 2005c
What Controls SF?What Controls SF?S
tar
form
atio
n ti
mes
cale
Gravitational instabilityLMK 2005d
Sta
r F
orm
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n E
ffic
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Galaxy Model
LMK 2005c
P2: SF in Interacting GalaxyP2: SF in Interacting Galaxy
Li, Mac Low & Dubinski, in prep
Merger vs. SingleMerger vs. Single
LMK 2004
Merger RemnantMerger Remnant
Mass distributionAge distribution
LMK 2004
Connection btw SF and BH GrowthConnection btw SF and BH Growth Similarity btw cosmic SFH and quasar evolution
(Madau et al. 96, Shaver et al 96) Starburst – AGN connection (Norman & Scoville 88,
Smith, Lonsdale & Lonsdale 98) MBH – correlation (Magorrian et al. 98, Ferrarese &
Merritt 00, Tremaine et al. 02) Most starburst gals are mergers (Sanders & Mirable
96, Alexanders et al 2004) Larger amount of CO in nearby merging galaxies
(Scoville 2000) and high-z QSOs (Walter 2002) QSO lifetimes 106 – 108 yrs (Martini 2004) Recent simulations (De Mateo, Springel & Hernquist
05, Kazantzidis et al. 05)
Simulated MSimulated MBHBH - - Relation Relation
Li, Haiman & Mac Low, in prep
Quasar LifetimesQuasar Lifetimes
Li, Haiman & Mac Low, in prep
SummarySummary Our simulations reproduce many obs. of SF in
gals -- the Schmidt Laws, SF thresholds… tot gravitational instability, CO SFE
Galaxy interaction trigger starburst. Higher SN of GCs, and bimodal metallicity dist. are natural products of gas-rich major mergers.
Merger also increase BH accretion, and the MBH – correlation is the fine-tuning of gas removal, in our case regulated by SF.
Quasar lifetime ranges 106 – 108 yrs, depending on the luminosity threshold