Nearby galaxies on gmc scales
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Nearby Galaxies on GMC Scales:. Massive complexes, cold dust, and the effect of environment Christine Wilson McMaster University. Interferometric Surveys for GMCs in Nearby Galaxies 1990-2000. Spiral Galaxies: M33: 44 clouds (Wilson & Scoville 1990, 1992, Viallefond et al. 1992)

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Nearby galaxies on gmc scales

Nearby Galaxies on GMC Scales:

Massive complexes, cold dust,

and the effect of environment

Christine Wilson

McMaster University


Interferometric surveys for gmcs in nearby galaxies 1990 2000

Interferometric Surveys for GMCs in Nearby Galaxies 1990-2000

Spiral Galaxies:

  • M33: 44 clouds (Wilson & Scoville 1990, 1992, Viallefond et al. 1992)

  • M31: 4 clouds (Vogel et al. 1987,Wilson & Rudolph 1993)

  • M81: 3 clouds (Taylor & Wilson 1998)

  • M83: 10 clouds (Rand et al. 1999)

    Dwarf Irregulars and Ellipticals:

  • NGC6822: 3 clouds (Wilson 1994)

  • IC10: 9 clouds (Wilson & Reid 1991, Wilson 1995)

  • NGC1569: 5 clouds (Taylor et al. 1999)

  • NGC185, NGC205: 1 cloud each (Young 2000,2001)


A complete survey of m33

A Complete Survey of M33

  • 148 GMCs (green) shown on HI map

  • complete to 1.5x105 Mo

  • mass function is N(m) ~ m-2.6, steeper than seen in Galaxy

  • An interferometric survey of M31 is also underway with IRAM (Guelin et al. 2001, Neininger 2001)

Engargiola et al. 2003; HI map Deul & van der Hulst 1987


Ngc 4214 interaction between ism and star formation walter et al 2001

NGC 4214: Interaction between ISM and Star Formation(Walter et al. 2001)

A wide distribution of molecular gas in IC 10(Walter 2003)


Giant clouds and star clusters in the antennae

Giant Clouds and Star Clusters in the Antennae

  • Hundreds of young massive star clusters discovered with HST

  • population of very massive clouds is unique among galaxies to date

Wilson et al. 2000, Whitmore et al. 1999

Wilson et al. 2003

Are very massive clouds required to form massive star clusters?


Two models for cluster formation

Two models for cluster formation

  • Shock compression of pre-existing GMCs to form a single massive cluster (Jog & Solomon 1992)

  • efficient star formation inside very massive cloud cores residing in supergiant molecular clouds (Harris & Pudritz 1994)

  • one possible distinguishing characteristic is pressure (108 K/cm3 in JS92 versus 105-106 K/cm3 in HP94)

  • typical pressure in Antennae 6x105 (Fabbiano et al. 2003)

  • since JS92 predicts volume filling factor of 1%, observed pressure is consistent with either model!

Observations of Antennae on sub-GMC scale required to distinguish between the models!


A double nucleus in m83 evidence of a minor merger

A Double Nucleus in M83: Evidence of a Minor Merger?

  • visible nucleus different from dynamical center

  • high-velocity gas traces gas disk rotating around visible “nucleus”

Sakamoto et al. 2004


Ngc 1569 evidence for cold dust

NGC 1569: evidence for cold dust

7.7 mm image 850 mm (contours) 15 mm image

Galliano et al. 2003

Spatial distribution of different dust components: 7.7 mm PAH, 15 mm small grains, colder grains in submillimeter


Scuba observations of dwarf galaxies

SCUBA Observations of Dwarf Galaxies

850 mm

NGC 1569

He 2-10

IIZw 40

NGC 1140

450 mm

Galliano et al (2003, 2004)


Nearby galaxies on gmc scales

SEDs of Four Dwarf Galaxies

NGC1140

NGC1569

NGC 1569

NGC 1140

He2-10

IIZw40

II Zw 40

He 2-10

Galliano et al (2003, 2004)


Alma and herschel

Sensitive, whole-galaxy surveys

access more distant galaxies so wider range of environments possible

higher spatial resolution for peak of dust SED and for cooling lines e.g. [CII]

Amount, location, nature of cold dust

link between cloud mass function and intense star formation

effects of metallicity on ISM structure and star formation process

ALMA and Herschel

Will provide a physical basis for understanding

dusty galaxies in the early universe!


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