Image of M8, taken by the AEOS Burst Camera
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Heather Swan
Physics Department
University of Michigan
Carl Akerlof, Timothy McKay, Eli Rykoff, Donald Smith, U of Michigan
Mark Skinner, Andrew Alday, Kevin Moore, Boeing LTS
Outline
• Why?
• What is the AEOS and ABC?
• GRB response
• Data and simulations
GRB 030418 was dimmer than expected at early times
Optical lightcurve
First image ~76s after -rays
Circum-burst absorbsoptical light
if we could see the spectrum, we would expect to see
red -> blue
GRB 990123 was brighter than expected at early times
-rays were still emitting for first few images
Optical lightcurve
Relativistic fireball – example of a reverse shock
if we could see the spectrum, we would expect to see
blue -> red
Swift’s BAT error box is the perfect size for the ABC
90% will be localized to a 3 arc minute radius
(Can see them with the ABC)
50% will be localized within 12 seconds
(Can see them promptly)
(From Fenimore, et al)
The AEOS telescope is a large optical telescope used by the Air Force
Advanced Electro-Optical Systems Telescope (AEOS)
Largest ground based AF optical telescope (3.67m)
Designed to track satellites, can quickly (~20 sec) slew to coordinates
Located in Haleakala, Hawaii, at 10,000 ftABC
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The AEOS Burst Camera (ABC) is attached to the AEOS
• Optics designed by Carl Akerlof
• Package designed by Alan Schier
• Camera built by Astronomical Research Cameras
Field of view 6' x 6'
Focal length of 15.5m
9 ToO observations / year Limiting Mag ~22nd for 10 sec exposure
Burst Filter
Fax::::::::::::::
GCN
SwiftGRB
User Interface
ABC Computers(Modified ROTSE
Software)
CD
The ABC will try to observe GRBs within minutes after they are localized
No prompt response yet…
• GRB needs to be < 1 hour old and visible in Maui
• The few that have been attempted– Bad weather– Bad pointing
• Several test bursts have been sent– Responses between 1 and 10
minutes
• One was caught during testing (030329)– Images taken several days after
the event
GRB 030329
A diffraction grating was recently installed on the ABC
• Low resolving power (8)• Installed Jan ’05
A light bulb viewed through the grating, and a star….
Simulations of the grating are similar to what is seen
Pixels
Inte
nsi
ty 0th
1st
2nd
higher orders
The blaze angle was chosen so most of the light would be in the 1st order
Blackbody, sun’s temp
Image from ABC of a star
Simulations of different temperature blackbodies
We can differentiate between blue and red stars
Hotter temps
Cooler temps
We can differentiate between different types of objects
Star
Quasar
Symbioticbinary
In summary, the ABC is up and running, we’re just waiting for a GRB
• The ABC can quickly and deeply observe GRBs– First image within minutes of GRB detection
– Small 6’ x 6’ field of view
– Deep (22nd mag) images with 10s exposures
• The ABC has a diffraction grating– Will get early spectral information for GRBs
Questions?