Light Detectives
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Transcript of Light Detectives
Light Detectives
Light DetectivesUsing NASA’s WISE Data to Identify Brown Dwarfs and ULIRGs
Limb of Sun
Very low mass star
Brown dwarf Brown dwarf
Jupiter
Brown dwarfs
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Where is the brown dwarf?
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How do astronomersknow what they know?
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W1 = 3.4 micronsW2 = 4.6 micronsW3 = 12 microns2
COLOR
Regular Stars Brown Dwarfs(more green [W2], less blue [W1])
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Where is the brown dwarf?
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Let’s find a brown dwarf more scientifically using real NASA data
The Process:1. Find and download the data2. Make measurements3. Plot and interpret the
results
Finder Chart• A finder chart
shows you where to find objects in the sky.
• The same objects will appear in each of the WISE images you download.
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How do astronomersknow what they know?
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W1 = 3.4 micronsW2 = 4.6 micronsW3 = 12 microns2
COLOR
Regular Stars Brown Dwarfs(more green [W2], less blue [W1])
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0.05 0.1 0.15 0.2 0.25 0.3 0.350.2
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Sample color-color diagram for brown dwarf search W2/W1 vs W3/W2
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W3/W2
W2/
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• Brown dwarfs have LOW intensity in W1.
• Brown dwarfs are relatively BRIGHT in W2 light.
• What objects have high W2/W1 ratios?
• What objects have higher W3/W2 ratios than brown dwarfs?
Color-Color Diagram
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W3/W2
W2/
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Brown Dwarfs
AGB Stars
Stars Normal Galaxies
ULIRGs
ULIRGsUltra-Luminous Infrared Galaxies
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Arp 220
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Finder Chart• A finder chart
shows you where to find objects in the sky.
• The same objects will appear in each of the WISE images you download.
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0.0 1.0 2.0 3.0 4.0 5.0 6.00.0
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Sample color-color diagram for ULIRG searchW2/W1 vs W3/W2
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WISE color image
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WISE color imageHubbleimage
ULIRG created by two merging galaxies!