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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 afterglow candidate
  2. GRB020813, optical observations
  3. Millimeter observation of GRB 020813
  4. GRB020812: optical observations
  5. GRB 020813 : KISO multiband optical observations
  6. GRB020813, optical observations
  7. IPN error box for GRB020813
  8. IPN triangulation of GRB020813
  9. GRB020812: possible afterglow candidate
  10. Early Time Limits for GRB020813
  11. GRB020812: possible afterglow candidate
  12. GRB020813, astrometric position
  13. Spectropolarimetry of GRB 020813
  14. GRB 020813 Afterglow Observations; Possible break
  15. GRB 020813: Absorption redshift
  16. GRB 020813 multiband optical observations
  17. GRB020813: optical afterglow
  18. GRB020813: Fading of Candidate OT
  19. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  20. GRB020813: Candidate Optical Afterglow
  21. GRB 020812 optical observation
  22. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  23. GRB 020715, optical observations
  24. GRB 020714, optical observations
  25. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  26. GRB020801: Candidate OT present in DSS
  27. HST Imaging of the Host of GRB 011121
  28. GRB020801, optical afterglow candidate
  29. Further refinement to IPN error box for GRB020531
  30. GRB020331: Late-time Optical Light Curve (re-submission)
  31. GRB020331: Late-time Optical Light Curve
  32. GRB 020405: HST observations reveal red bump
  33. IPN triangulation of GRB020714
  34. IPN triangulation of GRB020715 (=GRB150702)
  35. IPN triangulation of GRB020714
  36. IPN triangulation of GRB150702
  37. GRB 020410: Discovery of Probable OT by HST
  38. GRB 020124, HST observations of the fading afterglow
  39. IPN triangulation of GRB020708
  40. IPN triangulation of GRB020708
  41. IPN error box for GRB020706
  42. Correction to IPN error box for GRB020706
  43. IPN triangulation of GRB020706
  44. GRB 020705: Optical observations
  45. GRB 020625, optical observations
  46. GRB 020625: Optical observations
  47. GRB 020531: optical photometry of Chandra sources
  48. GRB020625 (=H2081): A Long Burst Localized by HETE
  49. HETE #2081: Optical observations
  50. The Probable Host Galaxy of GRB/XRF 020427
  51. GRB/XRF 020427, detection of an underlying system with the VLT
  52. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  53. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  54. AXP 1E2259+586: quasi-simultaneous optical observation
  55. AXP 1E2259+586 optical observations
  56. Fading Optical Source in the Field of GRB020531
  57. GRB 020531, INT+WFC deep optical upper limits
  58. SGR-like Bursts from the AXP 1E 2259+586
  59. GRB020405: polarimetric observations
  60. GRB 020531, simultaneous optical observations
  61. GRB 020604, optical observations
  62. GRB 020531/Candidate Redshift
  63. GRB020531: Detection of Candidate Host Galaxy
  64. GRB020531: Second epoch Chandra observations
  65. GRB020604, optical observations
  66. GRB020604, BVRcIc field photometry
  67. GRB020603, BVRcIc field observations
  68. GRB020531, BVRcIc field photometry
  69. GRB020531 Optical observations with TAROT
  70. GRB020531 Optical observations with TAROT
  71. GRB 020418, optical/near-IR observations
  72. GRB 020531, Radio Observations
  73. IPN triangulation of GRB020604
  74. GRB020531 Optical Observations
  75. GRB020531: Observations with the Chandra X-ray Observatory
  76. GRB 020603: Optical Observations
  77. GRB 020603, R-band observation
  78. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  79. GRB020531: Upper Limit for Detection of Two TAROT Sources
  80. GRB 020603: Optical observations
  81. IPN triangulation of GRB020603 (possible short/hard GRB)
  82. GRB 020531 optical observations with TAROT
  83. Refined IPN error box for GRB020531
  84. GRB020531, optical observations
  85. GRB020531: optical observations
  86. GRB020531, optical observation
  87. GRB020531(=H2042): Optical Observations
  88. IPN triangulation of the short, hard GRB020531 (=H2042)
  89. GRB020531(=H2042): Optical Observations
  90. GRB020531: Optical observations
  91. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  92. GRB 020525: Optical Observations
  93. GRB020525, optical observations
  94. IPN detection of possible bursts from SGR1806-20
  95. IPN triangulation of GRB020525
  96. XRF 020427: Sudden Ionospheric Disturbance (SID)
  97. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  98. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  99. IPN triangulation of a burst from SGR1806-20
  100. GRB/XRF 020427, Radio Observations

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