# Presentation: 303613

## USING THE INTERPLANETARY NETWORK TO SEARCH FOR SN Ic/GRB COINCIDENCES

- Kevin Hurley
- UC Berkeley
- Space Sciences Laboratory
- Berkeley, CA

**AGILE**

- Elena Pian
- INAF
- Astronomical Observatory of Trieste
- Trieste, Italy

## INTERPLANETARY NETWORKS OF GRB DETECTORS

- Have been in use since the late 1970’s
- Detect GRBs, SGRs, and other high energy transients (Cyg X-1, Sun, bursting pulsar, etc.)
- Current (3rd) IPN comprises 8 spacecraft (Ulysses, Mars Odyssey, MESSENGER, Wind, INTEGRAL, RHESSI, Suzaku, and Swift)
- 2 – 3 more missions will be added in the near future (Italian AGILE mission, NASA’s GLAST, Russian experiment on the Space Station)

## ADVANTAGES OF INTERPLANETARY NETWORKS

- True all-sky coverage (Earth-occultation is negligible due to the distances and number of the spacecraft)
- Almost 100% duty cycle, when all the spacecraft are considered
- The only technique in use to monitor the entire sky for transients
- Current GRB detection rate: 200/year (bursts which are *not* observed by narrow FOV instruments like Swift-BAT or INTEGRAL-IBIS)

## DISADVANTAGES

**Energy range covered is generally >25 keV, so soft spectrum GRBs (X-ray flashes, or XRF’s) are not detected**
**Not all localizations are precise**
**Experiments are small, so sensitivities are low**

## REALITY CHECK: DOES THE IPN DETECT KNOWN SN/GRBs?

| SN | GRB | DISTANCE,
Mpc | γ-RAY FLUENCE,
erg cm-2 | DETECTED? |
| --- | --- | --- | --- | --- |
| 1998bw	 | 980425
(BeppoSAX) | 35.6
	 | 4.4 x 10-6 | Yes |
| 2002lt	 | 021211
(HETE) | 6476 | 2.2x10-6
 | Yes |
| 2003dh		 | 030329
(HETE) | 788 | 1.2x10-4 | Yes |
| 2003lw	 | 031203
(IBIS) | 474 | 4x10-7 | Yes |
| 2006aj | 060218 
(Swift, XRF) | 150 | 6.8x10-6 | No
(for a variety of reasons) |

- Yes, if their spectra are not too soft

## SEARCHING FOR GRBs ASSOCIATED WITH OPTICALLY DETECTED SNe

- Select energetic Ic’s (Elena chairs the selection committee)
- Explosion times are not well constrained; search for GRBs in a 1-2 month time window
- 15 – 30 IPN bursts in this window
- Some are poorly localized; error boxes cover a large fraction of the sky
- Some random spatial/temporal coincidences are expected; most are not compelling

## ENERGETIC Ic’s

|  | SN | Distance, Mpc | Search Result |
| --- | --- | --- | --- |
| 1 | 1997dq | 13.8 | Several random coincidences |
| 2 | 1997ef | 49.2 | Several random coincidences |
| 3 | 1998ey | 67.5 | 1 random coincidence |
| 4 | 1999as | 579 | 1 random coincidence |
| 5 | 2001bb | 65.4 | Several random coincidences |
| 6 | 2002ap | 7.3 | No coincidences |
| 7 | 2002bl | 66.9 | 5 random coincidences |
| 8 | 2003L | 89 | 2 random coincidences |
| 9 | 2003bg | 18.9 | No coincidences |
| 10 | 2003cv | 119 | 1 random coincidence |
| 11 | 2003jd | 80.3 | No coincidences |
| 12 | 2004af | 243 | In progress |
| 13 | 2004aw | 243 | In progress |
| 14 | 2004bu | 77.8 | In progress |
| 15 | 2005da | 63.2 | In progress |
| 16 | 2007D | 96 | In progress |
| 17 | 2007I | 93 | In progress |

## CONCLUSIONS

- The IPN has detected 4 GRBs which are definitely associated with hypernovae; it did not detect one XRF/SN
- No convincing associations have been found between optically discovered hypernovae and IPN GRBs in 11 cases so far
- Assuming that GRBs were indeed produced in these events, then
- They were beamed away from us (beaming into 4π/11 events, or ~1 radian would explain the non-detections), or
- The GRBs produced were weak, <10-7 erg cm-2 (below the IPN fluence threshold), or
- The GRBs had very soft spectra, with little emission above 25 keV (~the IPN energy threshold), which would put them into the X-ray flash category, or
- Any combination of the above properties

## The IPN data are publicly available at ssl.berkeley.edu/ipn3,

**AGILE**

- or contact me at khurley@ssl.berkeley.edu