Post on 05-Feb-2016
description
Age-dating a Starburst:Age-dating a Starburst:Gemini/CIRPASS ObservationsGemini/CIRPASS Observations
of the Core of M83of the Core of M83
Age-dating a Starburst:Age-dating a Starburst:Gemini/CIRPASS ObservationsGemini/CIRPASS Observations
of the Core of M83of the Core of M83
Stuart Ryder & Robert Sharp Stuart Ryder & Robert Sharp AAOAAO
Johan Knapen Johan Knapen U. HertfordshireU. Hertfordshire
Lisa Mazzuca Lisa Mazzuca GSFCGSFC
Ian Parry Ian Parry U. CambridgeU. Cambridge
Circumnuclear Star FormationCircumnuclear Star FormationCircumnuclear Star FormationCircumnuclear Star Formation• Compact SF regions (“knots”) in ring/spiral < 1 kpc Compact SF regions (“knots”) in ring/spiral < 1 kpc
across.across.
• CSF most common in barred spirals.CSF most common in barred spirals.
• Bars “funnel” gas inwards, accumulates near Inner Bars “funnel” gas inwards, accumulates near Inner Lindblad Resonance (ILR): Lindblad Resonance (ILR): = = pp - - /2/2
• What triggers CSF?What triggers CSF?
– Critical gas density
– Spiral density wave
Random age spread
Age gradient
M83 (NGC 5236)M83 (NGC 5236)M83 (NGC 5236)M83 (NGC 5236)
AAT/IRIS2
HST/WFPC2F300WF547MF814W
Dyn/PhotCenter
50 pc
The HST ViewThe HST ViewThe HST ViewThe HST View
Harris et al. 2001, AJ, 122, 3046
Model: Starburst99Z=0.04, =2.35
Instantaneous Burst
AV=1old
young
Starburst Clock No. 1Starburst Clock No. 1Starburst Clock No. 1Starburst Clock No. 1• H recombination line (HH recombination line (H, Pa, Pa, Br, Br) equivalent widths.) equivalent widths.
• Leitherer et al. “Starburst 99” models:Leitherer et al. “Starburst 99” models:
Instantaneous Burst Continuous SFInstantaneous Burst Continuous SF
Starburst Clock No. 2Starburst Clock No. 2Starburst Clock No. 2Starburst Clock No. 2• CO band (2.29 CO band (2.29 m, 1.62 m, 1.62 m) spectroscopic index.m) spectroscopic index.
• Leitherer et al. “Starburst 99” models:Leitherer et al. “Starburst 99” models:
Instantaneous Burst Continuous SFInstantaneous Burst Continuous SF
The CIRPASS ViewThe CIRPASS ViewThe CIRPASS ViewThe CIRPASS View
The CIRPASS ViewThe CIRPASS ViewThe CIRPASS ViewThe CIRPASS View
Knot-by-knot analysisKnot-by-knot analysisKnot-by-knot analysisKnot-by-knot analysis
Region AnalysisRegion AnalysisRegion AnalysisRegion Analysis
Pa 1.28 m
Inside-out, or Outside-in?Inside-out, or Outside-in?Inside-out, or Outside-in?Inside-out, or Outside-in?
[Fe II] 1.64m
Sequential Triggering in M100Sequential Triggering in M100Sequential Triggering in M100Sequential Triggering in M100
SummarySummarySummarySummary• Photometry gives an incomplete/ambiguous age picture.Photometry gives an incomplete/ambiguous age picture.
• NIR IFU spectroscopy less biased by extinction and NIR IFU spectroscopy less biased by extinction and selection effects.selection effects.
• Multiple spectral line diagnostics help constrain Star Multiple spectral line diagnostics help constrain Star Formation Formation HistoryHistory..
• Clear azimuthal age gradients in M83 and M100 provide Clear azimuthal age gradients in M83 and M100 provide best evidence yet for sequential triggering via spiral best evidence yet for sequential triggering via spiral density wave-induced shock.density wave-induced shock.
• Ideal project for NIR MOS: GNIRS IFU will have Ideal project for NIR MOS: GNIRS IFU will have 3.33.3" " 4.8" FOV at 0.15" sampling, R=1700, full 4.8" FOV at 0.15" sampling, R=1700, full KK window includes Br window includes Br and CO (2,0) bands. and CO (2,0) bands.
“The cube is not enough”