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

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