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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 020812: optical observation at Bisei
  2. GRB020813: Early Time Magnitude
  3. GRB020813: optical observations; possible host galaxy
  4. GRB 020813, radio detection
  5. GRB 020812 : optical afterglow candidate
  6. GRB020813, optical observations
  7. Millimeter observation of GRB 020813
  8. GRB020812: optical observations
  9. GRB 020813 : KISO multiband optical observations
  10. GRB020813, optical observations
  11. IPN error box for GRB020813
  12. IPN triangulation of GRB020813
  13. GRB020812: possible afterglow candidate
  14. Early Time Limits for GRB020813
  15. GRB020812: possible afterglow candidate
  16. GRB020813, astrometric position
  17. Spectropolarimetry of GRB 020813
  18. GRB 020813 Afterglow Observations; Possible break
  19. GRB 020813: Absorption redshift
  20. GRB 020813 multiband optical observations
  21. GRB020813: optical afterglow
  22. GRB020813: Fading of Candidate OT
  23. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  24. GRB020813: Candidate Optical Afterglow
  25. GRB 020812 optical observation
  26. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  27. GRB 020715, optical observations
  28. GRB 020714, optical observations
  29. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  30. GRB020801: Candidate OT present in DSS
  31. HST Imaging of the Host of GRB 011121
  32. GRB020801, optical afterglow candidate
  33. Further refinement to IPN error box for GRB020531
  34. GRB020331: Late-time Optical Light Curve (re-submission)
  35. GRB020331: Late-time Optical Light Curve
  36. GRB 020405: HST observations reveal red bump
  37. IPN triangulation of GRB020714
  38. IPN triangulation of GRB020715 (=GRB150702)
  39. IPN triangulation of GRB020714
  40. IPN triangulation of GRB150702
  41. GRB 020410: Discovery of Probable OT by HST
  42. GRB 020124, HST observations of the fading afterglow
  43. IPN triangulation of GRB020708
  44. IPN triangulation of GRB020708
  45. IPN error box for GRB020706
  46. Correction to IPN error box for GRB020706
  47. IPN triangulation of GRB020706
  48. GRB 020705: Optical observations
  49. GRB 020625, optical observations
  50. GRB 020625: Optical observations
  51. GRB 020531: optical photometry of Chandra sources
  52. GRB020625 (=H2081): A Long Burst Localized by HETE
  53. HETE #2081: Optical observations
  54. The Probable Host Galaxy of GRB/XRF 020427
  55. GRB/XRF 020427, detection of an underlying system with the VLT
  56. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  57. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  58. AXP 1E2259+586: quasi-simultaneous optical observation
  59. AXP 1E2259+586 optical observations
  60. Fading Optical Source in the Field of GRB020531
  61. GRB 020531, INT+WFC deep optical upper limits
  62. SGR-like Bursts from the AXP 1E 2259+586
  63. GRB020405: polarimetric observations
  64. GRB 020531, simultaneous optical observations
  65. GRB 020604, optical observations
  66. GRB 020531/Candidate Redshift
  67. GRB020531: Detection of Candidate Host Galaxy
  68. GRB020531: Second epoch Chandra observations
  69. GRB020604, optical observations
  70. GRB020604, BVRcIc field photometry
  71. GRB020603, BVRcIc field observations
  72. GRB020531, BVRcIc field photometry
  73. GRB020531 Optical observations with TAROT
  74. GRB020531 Optical observations with TAROT
  75. GRB 020418, optical/near-IR observations
  76. GRB 020531, Radio Observations
  77. IPN triangulation of GRB020604
  78. GRB020531 Optical Observations
  79. GRB020531: Observations with the Chandra X-ray Observatory
  80. GRB 020603: Optical Observations
  81. GRB 020603, R-band observation
  82. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  83. GRB020531: Upper Limit for Detection of Two TAROT Sources
  84. GRB 020603: Optical observations
  85. IPN triangulation of GRB020603 (possible short/hard GRB)
  86. GRB 020531 optical observations with TAROT
  87. Refined IPN error box for GRB020531
  88. GRB020531, optical observations
  89. GRB020531: optical observations
  90. GRB020531, optical observation
  91. GRB020531(=H2042): Optical Observations
  92. IPN triangulation of the short, hard GRB020531 (=H2042)
  93. GRB020531(=H2042): Optical Observations
  94. GRB020531: Optical observations
  95. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  96. GRB 020525: Optical Observations
  97. GRB020525, optical observations
  98. IPN detection of possible bursts from SGR1806-20
  99. IPN triangulation of GRB020525
  100. XRF 020427: Sudden Ionospheric Disturbance (SID)

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