Gamma-ray Burst 020418

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN/BACODINE POSITION NOTICE


TITLE:             GCN/IPN POSITION NOTICE
NOTICE_DATE:       Fri 19 Apr 02 09:58:03 UT
NOTICE_TYPE:       IPN Single Box
IPN_NUMBER:        260
GRB_DATE:          12382 TJD;   108 DOY;   02/04/18
GRB_TIME:          31056.00 SOD {08:37:36.00} UT
GRB_IPN_RA:        120.0732d {+08h 00m 18s} (J2000),
                   120.0900d {+08h 00m 22s} (current),
                   119.7062d {+07h 58m 49s} (1950)
GRB_IPN_DEC:       -48.6454d {-48d 38' 42"} (J2000),
                   -48.6518d {-48d 39' 05"} (current),
                   -48.5067d {-48d 30' 23"} (1950)
GRB_ERROR1_RA1:    120.1820d {+08h 00m 44s} (J2000)
GRB_ERROR1_DEC1:   -48.6363d {-48d 38' 10"} (J2000)
GRB_ERROR1_RA2:    119.9323d {+07h 59m 44s} (J2000)
GRB_ERROR1_DEC2:   -48.6165d {-48d 36' 58"} (J2000)
GRB_ERROR1_RA3:    120.2142d {+08h 00m 51s} (J2000)
GRB_ERROR1_DEC3:   -48.6742d {-48d 40' 26"} (J2000)
GRB_ERROR1_RA4:    119.9644d {+07h 59m 51s} (J2000)
GRB_ERROR1_DEC4:   -48.6544d {-48d 39' 15"} (J2000)
GRB_ERROR:         4.99 [arcmin radius of circumscribing circle, 3 sigma]
GRB_BOX_AREA:      21 [sq.arcmin]
GRB_PEAK_FLUX:     unknown [erg/cm2/sec]
GRB_FLUENCE:       unknown [erg/cm2]
GRB_DURATION:      unknown [sec]
SUN_POSTN:          26.15d {+01h 44m 35s}  +10.82d {+10d 48' 56"}
SUN_DIST:          100.69 [deg]
MOON_POSTN:         91.46d {+06h 05m 50s}  +24.60d {+24d 36' 08"}
MOON_DIST:          77.60 [deg]
COMMENTS:          IPN triangulation localization.  
COMMENTS:          This is a preliminary, 3 sigma error box.  
COMMENTS:          GCN message is being issued.

red DSS finding chart ps-file
GCN notice #1376
K. Hurley, on behalf of the Ulysses GRB team;
F. Frontera, C. Guidorzi, and E. Montanari, on behalf of the BeppoSAX GRBM team;
I. Mitrofanov, D. Anfimov, A. Kozyrev, M. Litvak, and A. Sanin, on behalf of the HEND/Odyssey GRB team;
T. Cline, on behalf of the Ulysses and Mars Odyssey GRB teams;
W. Boynton, C. Fellows, K. Harshman, C. Shinohara, and R. Starr, on behalf of the GRS/Odyssey GRB team, report:
Ulysses, Mars Odyssey - HEND, and BeppoSAX observed this GRB at 31110 s. As observed by Ulysses, it had a duration of ~15 seconds, a 25-100 keV fluence of ~10^-5 erg/cm2, and a peak flux of ~10^-6 erg/cm2 s over 0.25 s.
We have triangulated it to a preliminary, 3 sigma error box with approximate area 20 square arcminutes whose coordinates are:
```
                     RA(2000)                 DEC(2000)
 
 ERROR BOX CENTER:   08 h 00 m 17.58 s    -48 o 38 '  43.64 " 
 ERROR BOX CORNER 1: 08 h 00 m 43.70 s    -48 o 38 '  11.00 " 
 ERROR BOX CORNER 2: 07 h 59 m 43.77 s    -48 o 36 '  59.65 " 
 ERROR BOX CORNER 3: 08 h 00 m 51.42 s    -48 o 40 '  27.43 " 
 ERROR BOX CORNER 4: 07 h 59 m 51.46 s    -48 o 39 '  16.15 "
```
This error box can be improved.
GCN notice #1377
P.A. Price, B.P. Schmidt (RSAA, ANU) and T.S. Axelrod (Arizona) report:
We have observed the error box of GRB 020418 (GCN #1376) with the robotic MSO 50-inch telescope + MACHO imager at 2002 Apr 19.42 UT (approximately 25.5 hours after the GRB) with 3 x 300 sec exposures. The combined image covers the entire error box down to a limiting magnitude of R ~ 21.1 mag, based on comparison with USNO-A2.0 magnitudes. We do not find any convincing afterglow candidate upon visual comparison with the second Digitised Sky Survey down to the plate limit, R ~ 20.5 mag.
Further observations are planned.
This message may be cited.
GCN notice #1379
P.A. Price, B.P. Schmidt (RSAA, ANU) and T.S. Axelrod (Arizona) report:
We have re-observed the error box of GRB 020418 (GCN #1376) with the robotic MSO 50-inch telescope + MACHO imager at 2002 Apr 20.41 UT to search for variable sources that might be the afterglow. On PSF-matched image subtraction from our first epoch image (GCN #1377), we do not find any afterglow candidate to the limiting magnitude of our first epoch images (R ~ 21.2 mag).
This message may be cited.
GCN notice #1419
J. Gorosabel* (IAA-CSIC Granada), J. Hjorth, P. Jakobsson, J. Rasmussen, B. L. Jensen, H. Pedersen (Univ. of Copenhagen), J. M. Castro Ceron* (ROA San Fernando), A. Hornstrup (DSRI Copenhagen), A.O. Jaunsen (ESO Paranal), M. Weidinger, J. Fynbo* (IFA Aarhus), M. I. Andersen (Univ. of Oulu), P. Moller (ESO Garching), S. Holland (Univ. of Notre Dame), A. J. Castro-Tirado (IAA-CSIC Granada), E. Pian (INAF, OA Trieste), A. Fruchter (STScI, Baltimore), J. Greiner (MPE Garching and AI Potsdam), L. Kaper, E. van den Heuvel (Univ. of Amsterdam), on behalf of the GRACE collaboration, report:
We summarise the results of an optical and near-infrared search for the afterglow of GRB 020418 carried out with the 1.54-m Danish Telescope and the 3.58-m New Technology Telescope, both at ESO's La Silla observatory.
The log of the observations is displayed in the following table:
```
 =========================================================================
       Date UT       Filter ExpTime Telescope   Seeing Time since Error box
       2002                   (s)  (+Instrument) (")   GRB (days) Coverage (%)
 --------------------------------------------------------------------------
 April 19.9435--20.0066 Ks  45x60 3.58NTT(+SOFI) 0.65    1.6150    60**
 April 19.9445--19.9935 J   20x60 3.58NTT(+SOFI) 0.65    1.6089    60**
 April 19.9760--20.0507 R  10x420 1.54D(+DFOSC)  1.05    1.6532    100
 April 20.9541--21.0177 Ks  45x60 3.58NTT(+SOFI) 0.70    2.6258    60**
 April 20.9551--21.0052 J   20x60 3.58NTT(+SOFI) 0.70    2.6200    60**
 April 20.9720--21.0340 R   6x500 1.54D(+DFOSC)  0.90    2.6429    100
 June  01.9642--02.0267 R   9x500 1.54D(+DFOSC)  1.90   44.6353    100
 June  02.9592--03.0155 R   8x500 1.54D(+DFOSC)  1.40   45.6273    100
 --------------------------------------------------------------------------
 ** Central part
 ==========================================================================
```
Comparison of the images reveals no variable source contained in the error box brighter than R = 23.0. Correcting for the effect of the Galactic extinction, the R-band upper limit corresponds to R = 22.3.
For the central part of the error box (the 60% of the error box covered for SOFI) we can set limits of Ks >= 21.0, J >= 22.6 and R >= 22.3 for any variable source (magnitudes corrected for Galactic reddening).
We acknowledge the assistance of L. Vanzi at La Silla.
* Visiting the Astronomical Observatory of the University of Copenhagen.

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Jochen Greiner, last update: 08-Jun-2002 [Disclaimer]