Gamma Ray Burst 120909A


[Sept. 10, 2012] 
Maybe following this event can be a point of discussion of the science and the use of Skynet?
I [Rich DeCoster; ricdec@starsatyerkes.net] will try to follow this event and its subsequent analysis and put some of the material here.  Discussion is encouraged.  

The GRB that reached Earth during Viv's Stars at Yerkes Workshop presentation on Skynet Saturday [Sept. 8] has been given the name GRB 120909A since its signal reached Earth on Sept. 9, UT.  Information can be found at this url: http://heasarc.gsfc.nasa.gov/docs/swift/archive/grb_table/120909A/ 
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Here is the initial contribution of PROMPT to the observation of this event: If we log in to Skynet we should be able to find the PROMPT images and find their observations of this guy.
TITLE:   GCN CIRCULAR
NUMBER:  13728
SUBJECT: Skynet/PROMPT Observations of GRB120909A
DATE:    12/09/09 02:24:04 GMT
FROM:    Aaron LaCluyze at U.North Carolina  <lacluyze@email.unc.edu>

J. Haislip, A. LaCluyze, K. Ivarsen, D. Reichart, J. Moore, H. T. 
Cromartie, R. Egger, A. Foster, N. Frank, M. Nysewander, A. Oza, E. 
Speckhard, A.Trotter, and J. A. Crain report:

Skynet observed the field of GRB120909A (GCN 13727, Swift trigger #533060) 
with the PROMPT telescopes located at CTIO in Chile beginning ~4 minutes 
after the burst. We detect a fading, uncataloged source at RA 18:22:56.72 
DEC -59:26:54.0, roughly coinciding with the location of the Swift trigger 
with an initial magnitude of ~16.3 in R, calibrated to the NOMAD catalog.
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Further observations are ongoing. 

If you go to the bottom of the page there are a number of other urls [of GCN] for updated information.  As this event is studied in more detail, additional GCN [GRB Coordinates Network (GCN)] will be issued.
Its redshift has now been measured, at least provisionally [z~3.9].   http://gcn.gsfc.nasa.gov/gcn3/13730.gcn3 
The event was far away and a long time ago!  Here's a link to Ned Wright's "cosmology calculator" to find out.  The universe appears to be "FLAT,"  so you may wish to use that choice.  http://www.astro.ucla.edu/~wright/CosmoCalc.html

This makes it only one of about 200 GRBs for which redshifts have been determined.  Here is a paragraph about these guys and SWIFT from a recent [8/24] review article in Science.  Although Skynet is not mentioned explicitly in the review, the network of telescopes is.  The reason that Skynet exists is because of its use by the SWIFT program.  You or your students may wish to follow continuing developments of the GRB and see what contributions the PROMPT telescopes make to its study.


From Science: August 24, 2012

Swift GRB Observations

Mission and statistics. The Swift mission (7) has three instruments: the Burst Alert Telescope (BAT) (8), the X-Ray Telescope (XRT) (9), and the UV Optical Telescope (UVOT) (10). The BAT detects bursts and locates them to ~2–arc min accuracy. The position is then sent to the spacecraft to repoint the XRT and UVOT at the event. Positions are also rapidly sent to the ground so that ground telescopes can follow the afterglows. There are more than 50 such telescopes of all sizes that participate in these worldwide follow-up campaigns. Measurements of the redshift and studies of host galaxies are typically done with large ground-based telescopes, which receive immediate alerts from the spacecraft when GRBs are detected. Swift has, by far, detected the largest number of well-localized bursts with afterglow observations and redshift determinations. As of 1 April 2012, BAT has detected 669 GRBs (at an annual average rate of ~90 per year). Approximately 80% of the BAT-detected GRBs were observed by rapid repointings (the remaining 20% had spacecraft constraints that prevented rapid slewing). Of those, virtually all long bursts observed promptly had detected x-ray afterglow. Short bursts are more likely to have negligible x-ray afterglow, fading rapidly below the XRT sensitivity limit. The fraction of GRBs observed by rapid repointing that had UVOT detection is ~35%. Combined with ground-based optical observations, about ~60% of Swift GRBs had optical afterglow detection. There are 200 Swift GRBs with redshifts, as compared with 41 before Swift.

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