1. Update on the triggered search for GRBs
Pablo Saz Parkinson (UCSC)
Santa Cruz Collaboration Meeting, April 2007

2. Outline Update on GRBs in Milagro field of view Short GRB paper
Other searches:
Swift X-ray flares
Core-collapse Supernovae

3. Summary through 2006: 2000-2001: 25 GRBs, 3 with z, ApJ paper
Total (including 24 archival GRBs from IPN/BeppoSAX): 106 GRBs, with z, with z< 0.5, 4-6 with z<1

4. New in 2007
6 additional GRBs in Only two more GRBs with redshift ( at 1.5 and at 1.2)
TeV 99% UL limit : 5.8e-4 erg cm^-2
20-10,000 keV fluence = 1.7e-4 erg cm^-2

5. Short GRB paper: response to referee (1. deadtime)
1700 -> 9% tau = 50 us
1800 -> 12.5% tau = 70 us
1500 -> 5.3% tau = 35 us
1600 -> 6.8% tau = 40 us
For non-paralyzable deadtime:
tau=(n-m)/nm
n=true rate
m=observed rate
Deadtime with new trigger

6. Deadtime (cont’d) Deadtime with VME trigger
Deadtime with multiplicity trigger

7. Short GRB paper: Response to Referee (2. Other candidates)
Referee’s comment that predictions of Razzaque model don’t depend on redshift is wrong.
GRB which referee refers to would have a flux less than an order of magnitude of b

8. Short GRB paper: other changes
Added paragraph including two references to SGRs and nearby population of short bursts
Highlighted GRB (from M81?)
Give limits at z=0

9. Emission from X-ray flares
The First Survey of X-ray Flares from GRBs observed by Swift: Chincarini et al (astro- ph/ ), Falcone et al (about to be submitted)
All GRBs up to end January 2006
110 GRBs, 33 with X-ray flares, total of 77 flares
10 flares in Milagro FOV

10. Some examples of flares

11. Search for emission from Core Collapse SNe
Have a catalog of ~ 150 Type Ibc and 460 Type II in Milagro field of view.
A small percentage of these could be GRBs. We could set a good limit.
SNe are also predicted to produce shocks, emit high energy photons.
“trigger” time is not well defined (within ~ 1 month). Use “untriggered” code?

12. Conclusions We have searched 112 GRBs since 2000.
No VHE emission detected yet.
Also searched for emission from Swift flares
Should search for emission from CC SNe and nearby galaxies
Submit GRB paper next week?