IMF - - PDF document

1

近赤外広視野観測から探る褐色矮星・ 惑星質量天体とIMF

NIR Deep Wide Survey of Very Young Low-mass Objects Investigation of the Initial Mass Function at Very Low-Mass Side

Salpeter (1955)

Salpeter Kroupa Miller-Scalo Scalo

logM →massive

  Salpeter’s law

Increase monotonously

Scalo’s law

Peark around 0.3Mo But, data incompleteness

Kroupa’s law

Peak around 0.1 Mo? But, data incompleteness

  Brown Dwarf Planetary- Mass Object Brown Dwarf Planetary- Mass Object 年齢 1Myr 10Myr 100Myr 1Gyr 10Gyr

The track of Burrows et al. (1997)

1 10-

2

10-

４

10- 光度 (L/Lo)

Field Pleiades

軌道半径(AU) 0.01 100 質 量 ( 木 星 質 量 ) 0.01 10m/s 12年 １ 1 age Sun SFR

Luminosity

• 4
• 8

Forming PMOs are brighter 4th order

Star Brown Dwarf Planetary-Mass Object

  Sun

M dwarf L dwarf T dwarf

Jupiter Star Brown Dwarf Planet

1Myr 10Myr

Sun

M dwarf L dwarf T dwarf

Jupiter Star Brown Dwarf Planet 0.26pc (5.5’)

Young BD and PMOs in Perseus Oasa et al. in prep.

1 2 6 7

2

IMF – Massive SFRs Orion, NGC3603 -

 

Brown Dwarf Low-Mass Star Planetary Mass Object Brown Dwarf Low-Mass Star



IMF Massive SFR OriB

IMF

• Massive

SFR S106-

• 2 -1 0

Log[N/logMo]

Log[M/Mo]

Group2 Group3 Group1

  Brown Dwarf Planetary- Mass Object Low- Mass Star

Dust clump with CO gas

E N Cluster A Cluster B

Dust clump without CO gas

IMF –Intermediate mass SFRs Serpens-

Spitzer/IRAC

16 18 19 21

3

 

Log[N/logMo]

1Myr 0.3Myr

Log[M/Mo]

Clump MF

IMF – Intermediate mass SFR RCrA & NGC1333-

5’

Planetary- Mass Objects Brown Dwarfs Low-Mass Stars

IMF – low mass SFRs Ophiuchi-

Brown Dwarfs Low-Mass Stars Planetary- Mass Objects

N/Mo

Brown DwarfsLow-Mass Stars Planetary- Mass Objects

IMF – Other Clusters & Field -

 

Q: Substellar-mass objects form everywhere?

 

field in M31 using

2MASS Image of NGC7538 11.0´ × 11.0´



LMC IMF Carlson et al. (2012)

Carlson et al. 2012

37 38 39 40

4

   

Summary

Open Questions

Is the lower mass objects increasing also in the other regions? What key physical processes govern the formation of BDs and

PMOs?

Is the process same as “star” or “planet”? The lower end of IMF would be variable. What determines it? Over a range of mass, metallicity, stellar density, and environment

41