light detectives
DESCRIPTION
Light Detectives. Using NASA’s WISE Data to Identify Brown Dwarfs and ULIRGs. Light Detectives. Light Detectives – #2. Brown dwarfs. Limb of Sun. Brown dwarf. Brown dwarf. Very low mass star. Jupiter. Where is the brown dwarf?. Light Detectives – #3. How do astronomers - PowerPoint PPT PresentationTRANSCRIPT
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 micronsW2 = 4.6 micronsW3 = 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 micronsW2 = 4.6 micronsW3 = 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
0.3
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0.8
1211 10
9
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54
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1
Sample color-color diagram for brown dwarf search W2/W1 vs W3/W2
123456789101112
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
0.4
0.6
0.8
1.0
1.2
12
11
1098
765 4
321
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!