light detectives. limb of sun very low mass star brown dwarf jupiter light detectives – #2
TRANSCRIPT
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
Light Detectives – #2
Where is the brown dwarf?
Light Detectives – #3
How do astronomersknow what they know?
Light Detectives – #4
W1 = 3.4 microns
W2 = 4.6 microns
W3 = 12 microns2
COLOR
Regular Stars Brown Dwarfs(more green [W2], less blue [W1])
Light Detectives – #5
Where is the brown dwarf?
Light Detectives – #6
Light Detectives – #7
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.
Light Detectives – #8
How do astronomersknow what they know?
Light Detectives – #9
W1 = 3.4 microns
W2 = 4.6 microns
W3 = 12 microns2
COLOR
Regular Stars Brown Dwarfs(more green [W2], less blue [W1])
Light Detectives – #10
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/
W1
• 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
Light Detectives – #11
0 1 2 3 4 5 6 7 8 9
W3/W2
W2/
W1
5 4
3 2 1
0
Brown Dwarfs
AGB Stars
Stars Normal Galaxies
ULIRGs
ULIRGsUltra-Luminous Infrared Galaxies
Light Detectives – #12
Light Detectives – #13
Arp 220
Light Detectives – #14
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.
Light Detectives – #15
0.0 1.0 2.0 3.0 4.0 5.0 6.00.0
0.2
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1.0
1.2
12
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1098
765
432
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Sample color-color diagram for ULIRG searchW2/W1 vs W3/W2
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W3/W2
W2/
W1
Light Detectives – #16
WISE color image
Light Detectives – #17
WISE color imageHubbleimage
ULIRG created by two merging galaxies!