K. Malek 1) , L.W. Piotrowski 2) , M. Biskup 2) , M. Cwiok 2) , M.Denis 3) , W. Dominik 2) , J.Grygorczuk 3) , G.Kasprowicz 4) , J.Juchniewicz 3) , M. Kwiatkowski 4) , A. Majczyna5 ) , A. Majcher 1) , L. Mankiewicz 1) , M. Molak4), K. Nawrocki 5 ),
K. Malek1),L.W. Piotrowski2), M. Biskup2), M. Cwiok2), M.Denis3), W. Dominik2), J.Grygorczuk3), G.Kasprowicz4), J.Juchniewicz3), M. Kwiatkowski4), A. Majczyna5), A. Majcher1), L. Mankiewicz1), M. Molak4), K. Nawrocki5),
R. Pietrzak3), K. Pozniak4), R. Romaniuk4), D. Rybka5), P. Sitek5), M. Sokolowski5), J. Uzycki4), P. Wawer3), R. Wawrzaszek3), G. Wrochna5), M. Zaremba4), A.F. Zarnecki2)
1) Center for Theoretical Physics, Polish Academy of Sciences; 2) Institute of Experimental Physics, University of Warsaw;
3)Space Research Centre, Polish Academy of Sciences; 4) Warsaw University of Technology;5) Soltan Institute for Nuclear Studies;
Special thanks to prof. B. Paczynski (Princeton University) and G. Pojmanski (Warsaw University) and all staff of the Las Campanas Observatory.
of the Sky
Always on time!
Innovative approach to GRB optical counterparts and other short optical transients detection
Study of astrophysical phenomena with time scale from seconds to months
We present an innovative approach to the GRB optical counterparts observations, which ought to overcome one of the main obstacles towards deeper understanding of GRB phenomenon: only a few observations in the very early stage of the burst. The “ of the Sky” introduces the idea of constant, high time resolution, large sky area monitoring. Efficient data stream reduction algorithms were created for optical transient detections not depending on GRB satellites.
GRB prompt optical emission (even prior to burst)
participation in multiwavelength campaigns
search for new fast varying objects
flare star outburst
variable stars (including novae)
continuous large sky area monitoring
images prior to satellite triggers
high time resolution
Final mount design
FULL SYSTEM (under construction)
FIRST RESULTS (from prototype)
Search for GRB optical counterparts:
217 GCN alerts received (>7.2004):
9 apparatus off 11 clouds 59 below horizon
103 daytime 32 FoV change required 3 inside current FoV
limits 9m – 14.3m published:
GRB 040916, 041217, 050123, 050326, 050607, 060607, 060719, 061202, 070521
limits during the burst: GRB 040825A, GRB 050412
Search for optical flashes:
132 flashes < 10s detected (may be flashing satellites)
8 flashes >10s detected (including flare of CN Leo)
Outburst of CN Leo flare star, automatically detected on-line. Star was not visible in our range before its outburst, thus it well simulates expected behavior of GRB optical counterpart.
Modes of observation
The prototype system works autonomously, according to schedule, which could be changed via Internet:
follows SWIFT or Integral FoV
independently detects optical flashes in real time (self-triggering)
instantaneously follows satellite alerts distributed by GCN
performs dedicated observations of interesting objects (eg. blasars, quasars, novae) in spare-time
twice a night makes a full sky survey (2x40 min)
IS OUR RANGE SUFFICIENT?
Knowledge about early brightness is weak, for most optical counterparts were observed long after GRB. How to estimate number of bursts expected in “ of the Sky” range?
Number of objects per night at different trigger steps. Level 1 consists of very fast and simple cuts mainly for eliminating constant stars and apparatus effects. Coincidence performed at the last step of Level 1 mainly eliminates cosmic ray effects. Level 2 eliminates real objects like satellites, planes and meteors not reduced by Level 1.
Results of extrapolation of 45 early lightcurves (<5000s) to 30 s after GRB. The average brightness, not filter corrected, is. 15.7m. (data from GRBlog). Dashed lines – our limits with and without filter correction.
Maximal GRB optical counterpart brightness in the first 100 s after GRB, for 39 bursts. The average brightness, not filter corrected, is 15.9m (data from GRBlog).
Both the extrapolation and the real maximal magnitude show, that we should be able to see close to one third of the GRB optical counterparts (during night, in our hemisphere). That is very optimistic!