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

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