AT2018cow

• GSC Light Curve

• The source sky postion of (RA, Dec)=(244.00090, 22.26800) had been scanned every 90 minutes with good GSC units operated in the normal mode until 2016-06-14T05 (MJD 58283.2). After that time, it has been scanned by the GSC_#3 unit, which has a problem in the veto function for the anti-coincidence background cut. The background level got higher by an order of magnitude, and thus the sensitivity became worse by a factor of 4-5. The relatively large systematic uncertainties are also expected.
• The figure below shows the light curve from MJD 58280 to MJD 58290. Data marked by cross symbols (X) were taken by GSC_#3 or GSC_#6 counters with the degraded functionality. The error bars represent only the statistical uncertainties of 1-sigma.
• No significant emission has been recognized.

• CSV file includes 12 columns, from 2018-06-01 to 2018-06-25,
  1. MJD time of scan or bin center
  2. MJD time of scan or bin start
  3. MJD time of scan or bin end
  4. 2-20 keV rate
  5. 2-20 keV rate error
  6. 2-4 keV rate
  7. 2-4 keV rate error
  8. 4-10 keV rate
  9. 4-10 keV rate error
  10. 10-20 keV rate
  11. 10-20 keV rate error
  12. Data taken by function-limited GSCs including GSC_#3 and GSC_#6 (1), or not (0)