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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
  1. Polarimetry of GRB020813: evidence for variability
  2. GRB020813 IRAM millimeter observations
  3. GRB020812: optical observations
  4. GRB020813: High-Resolution Optical Observations
  5. GRB020813(=H2262): Revised Localization with HETE SXC
  6. GRB 020812: optical observation at Bisei
  7. GRB020813: Early Time Magnitude
  8. GRB020813: optical observations; possible host galaxy
  9. GRB 020813, radio detection
  10. GRB 020812 : optical afterglow candidate
  11. GRB020813, optical observations
  12. Millimeter observation of GRB 020813
  13. GRB020812: optical observations
  14. GRB 020813 : KISO multiband optical observations
  15. GRB020813, optical observations
  16. IPN error box for GRB020813
  17. IPN triangulation of GRB020813
  18. GRB020812: possible afterglow candidate
  19. Early Time Limits for GRB020813
  20. GRB020812: possible afterglow candidate
  21. GRB020813, astrometric position
  22. Spectropolarimetry of GRB 020813
  23. GRB 020813 Afterglow Observations; Possible break
  24. GRB 020813: Absorption redshift
  25. GRB 020813 multiband optical observations
  26. GRB020813: optical afterglow
  27. GRB020813: Fading of Candidate OT
  28. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  29. GRB020813: Candidate Optical Afterglow
  30. GRB 020812 optical observation
  31. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  32. GRB 020715, optical observations
  33. GRB 020714, optical observations
  34. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  35. GRB020801: Candidate OT present in DSS
  36. HST Imaging of the Host of GRB 011121
  37. GRB020801, optical afterglow candidate
  38. Further refinement to IPN error box for GRB020531
  39. GRB020331: Late-time Optical Light Curve (re-submission)
  40. GRB020331: Late-time Optical Light Curve
  41. GRB 020405: HST observations reveal red bump
  42. IPN triangulation of GRB020714
  43. IPN triangulation of GRB020715 (=GRB150702)
  44. IPN triangulation of GRB020714
  45. IPN triangulation of GRB150702
  46. GRB 020410: Discovery of Probable OT by HST
  47. GRB 020124, HST observations of the fading afterglow
  48. IPN triangulation of GRB020708
  49. IPN triangulation of GRB020708
  50. IPN error box for GRB020706
  51. Correction to IPN error box for GRB020706
  52. IPN triangulation of GRB020706
  53. GRB 020705: Optical observations
  54. GRB 020625, optical observations
  55. GRB 020625: Optical observations
  56. GRB 020531: optical photometry of Chandra sources
  57. GRB020625 (=H2081): A Long Burst Localized by HETE
  58. HETE #2081: Optical observations
  59. The Probable Host Galaxy of GRB/XRF 020427
  60. GRB/XRF 020427, detection of an underlying system with the VLT
  61. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  62. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  63. AXP 1E2259+586: quasi-simultaneous optical observation
  64. AXP 1E2259+586 optical observations
  65. Fading Optical Source in the Field of GRB020531
  66. GRB 020531, INT+WFC deep optical upper limits
  67. SGR-like Bursts from the AXP 1E 2259+586
  68. GRB020405: polarimetric observations
  69. GRB 020531, simultaneous optical observations
  70. GRB 020604, optical observations
  71. GRB 020531/Candidate Redshift
  72. GRB020531: Detection of Candidate Host Galaxy
  73. GRB020531: Second epoch Chandra observations
  74. GRB020604, optical observations
  75. GRB020604, BVRcIc field photometry
  76. GRB020603, BVRcIc field observations
  77. GRB020531, BVRcIc field photometry
  78. GRB020531 Optical observations with TAROT
  79. GRB020531 Optical observations with TAROT
  80. GRB 020418, optical/near-IR observations
  81. GRB 020531, Radio Observations
  82. IPN triangulation of GRB020604
  83. GRB020531 Optical Observations
  84. GRB020531: Observations with the Chandra X-ray Observatory
  85. GRB 020603: Optical Observations
  86. GRB 020603, R-band observation
  87. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  88. GRB020531: Upper Limit for Detection of Two TAROT Sources
  89. GRB 020603: Optical observations
  90. IPN triangulation of GRB020603 (possible short/hard GRB)
  91. GRB 020531 optical observations with TAROT
  92. Refined IPN error box for GRB020531
  93. GRB020531, optical observations
  94. GRB020531: optical observations
  95. GRB020531, optical observation
  96. GRB020531(=H2042): Optical Observations
  97. IPN triangulation of the short, hard GRB020531 (=H2042)
  98. GRB020531(=H2042): Optical Observations
  99. GRB020531: Optical observations
  100. GRB020531(=H2042): A Short, Hard Burst Localized by HETE

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