GRB 990217

Luigi Piro, BeppoSAX Mission Scientist, reports:

GB990217 refined WFC positions are:
R.A.(2000)= 45.7177
DEC(2000)= -53.0935
with an error radius of about 3'

A follow-on with NFI will start today around 12.00 UT

Bradley E. Schaefer (Yale) reports:

"I have examined the BeppoSAX error circle for GRB990217 (Tarei et al.
IAUCirc 7110) with the Yale 1-m telescope on Cerro Tololo.  At this early
time, the only comparison available is the Digital Sky Survey, and no
optical transient is apparent.  The images were taken in R and I starting
at 18 February 2:17 UT with 900s exposures, and these reach considerably
deeper than the Digital Sky Survey."

GRB 990217 B and R band observations

E. Palazzi, N. Masetti, E. Pian, F. Frontera (ITESRE-CNR, Bologna),
P.M. Vreeswijk, E. Rol, T.J. Galama, G. Dubus (U. of Amsterdam),
J. van Paradijs (U. of Amsterdam and U. of Alabama in Huntsville),
C. Kouveliotou (NASA-MSFC/USRA), O. Hainaut (ESO), C. Tinney (AAT),
T. Axelrod, B.  Schmidt, and H. Jones (MSSSO), on behalf of a large
collaboration, report:

"Images of the GRB 990217 error box (Tarei et al. 1999, IAU Circ. 7110) 
were acquired on 1999 Feb 17.50 UT at Siding Spring with the 40-inch
telescope (R band), on Feb 17.48 at Mount Stromlo with the 74-inch
telescope (R), on Feb 17.54 with the 50-inch telescope (B and R), on Feb
18.03-18.07 and Feb 19.04-19.12 at ESO-La Silla with NTT+EMMI (B and R). 
Limiting magnitudes were R~22.5 for the 40-inch, B~20 and R~21 for the
50-inch, R~22 for the 74-inch, B~24.5 and R~24.5 for NTT on Feb 18, and
B~24 and R~23.5 for NTT on Feb 19. 

Comparison between the NTT images of Feb 18 and 19 shows no object varying
by more than 0.3 magnitudes down to R~23.5 and B~24 within the error box in
either band. Similarly, the comparison between the 40-inch and the Feb 18
NTT R band images shows no object varying by more than 0.3 magnitudes down
to R~22.5 within the error box.


This message can be cited."

L. Amati, F. Frontera and N. Masetti (ITESRE/CNR, Bologna), E. Montanari
(University of Ferrara), E. Costa, M. Feroci and
L. Piro (IAS/CNR) report on behalf of the BeppoSAX/GRBM Team:

"The BeppoSAX Gamma Ray Burst Monitor detected GRB990217 (IAUC #7110) as a
weak, single pulse gamma-ray burst lasting about 25 s. The
total fluence in the 40-700 keV energy range is 4307 +/- 195 counts, 
corresponding to (1.3 +/- 0.2) x 10E-6 erg cmE-2. The 1 s peak flux in
the same band is 146 +/- 43 counts/s, corresponding to 
(1.1 +/- 0.3) x 10E-7 erg cmE-2 sE-1. For a comparison, the peak flux 
in the 2-26 keV range as measured by the BeppoSAX/WFC N. 2 (IAUC #7110) is 
about 0.5 Crab, that corresponds to 1.64 x 10E-8 erg cmE-2 sE-1.
The average photon index inferred from the GRBM data with the assumption
of a single power-law is 1.52 +/- 0.55. The low statistical quality of the
data does not allow to better constrain the spectral model."

This message is citeable.

R. Wark (CSIRO), M. Wieringa (CSIRO), D. A. Frail (NRAO) and
S. R. Kulkarni (Caltech) report on behalf of a larger collaboration:

"Beginning at 7:39 UT on 1999 February 18 we observed a region
covering the WFC error circle of GRB 990217 (GCN #258
Loading...
 
 , IAU Circ 7710)
with the Australia Telescope Compact Array (ATCA) at 4.8 GHz and 8.6
GHz.  The total observing time was 3.6 hours.

Within a 3 arcmin radius around the GRB position no radio sources were
detected down to 0.28 mJy (5 sigma) at either frequency. Deeper ATCA
observations are planned for this week."

This message is citeable.

K. Pedersen (Danish Space Research Institute, Copenhagen), 
J. Hjorth, H. Pedersen (Copenhagen University Observatory), and
A.O. Jaunsen (Institute for Theoretical Astrophysics, Oslo) report:

We have observed the field of GRB 990217 (Tarei et al., IAUC 7110), 
using the DFOSC instrument on the 1.54-m Danish telescope at 
La Silla.  All exposures were done in the R band. The field 
covered was 13.6 x 13.6 arcminutes, hence significantly larger 
than the BeppoSAX error circle.

UTC (mid exposure)    Exp.    Seeing (fwhm)   Limit

1999 Feb 19.049      1200 s        1.4"      < 23.1      
1999 Feb 20.034      1000 s        1.4"      < 23.0 
1999 Feb 24.037       600 s        1.2"      < 22.8 
 
Intercomparison of the exposure shows no variable object.