withMark Westmoquette (UCL)

Jay Gallagher (Wisconsin-Madison)Bob O’Connell (Virginia)

Richard de Grijs (Sheffield)

Linda J. SmithUniversity College London

MODEST-6 Workshop 29-31 August 2005

HST/STIS SPECTROSCOPY OF A YOUNGSSC IN THE STARBURST CORE OF M82

WFPC2 BVI+H

STScI-PRC2001-08b R. de Grijs

STIS slit =

52”

REGION A: 86 clusters!!

In projection:

Density of 1450 /kpc2

Mean separation = 11 +/- 5 pcMean radius = 5 +/- 2 pc(Melo et al. 2005)

A

180 pc

STIS slit position

52” x 0.1”

0”.1 = 1.8 pc

M82-A1

WFPC2 V-band image

STIS G430L + G750M spectra of M82-A1

• Age = 6.4 +/- 0.4 Myr• E(B-V) = 1.35 +/- 0.15 mag• V = 17.23 +/- 0.1 mag• MV = -14.8 +/- 0.4 mag• Mass = 7-13 x 105 Msun

• Half-light radius = 3.0 +/- 0.5 pc

• Mass density = 6-11 x 103 Msun

pc-3

[NII]+H

[SII]D

ist a

nce a

lon

g s

lit

->

Small HII region around M82-A1

•Half-light radius = 4.5 +/- 0.5 pc•Electron density = 1800 cm-3

•Pressure P/k = 2 x 107 cm-3 K