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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 010214: X-Ray afterglow
  2. GRB 010214, Optical Observations
  3. GRB 010214 optical observation
  4. GRB010213, Radio Observations
  5. GRB010213 Optical Observation
  6. GRB010213, Radio Observations
  7. J-Band Observation of GRB 010214.
  8. GRB010214, Radio Observations
  9. GRB010214, optical observations
  10. GRB010213, optical observations
  11. GRB010213, Near-IR observations
  12. Possible InfraRed Transient of GRB 010214.
  13. GRB010214 Optical Observation
  14. GRB010214: BeppoSAX/NFI Observations
  15. GRB010213 (HETE) TAROT observations
  16. GRB 010214, optical observations
  17. GRB010213 detected by HETE
  18. GRB010214 refined WFC position
  19. BeppoSAX ALERT: GRB010214
  20. IPN Status Report
  21. HETE Status
  22. GRB010126 opt. obs.
  23. IPN/RXTE TRIANGULATION OF GRB010126
  24. GRB010126: CONCAM crude optical limits during GRB
  25. GRB010126, TNG R-band observations
  26. GRB010126 Optical Observations
  27. GRB010126 optical observations
  28. GRB010126: Optical observations
  29. IPN TRIANGULATION OF GRB010126
  30. IPN/RXTE TRIANGULATION OF GRB010126
  31. GRB 010119, optical observations
  32. GRB010119: Optical observations
  33. Optical Observations of GRB 001018 at Keck
  34. GRB010119, Radio observations
  35. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  36. Optical observations of GRB 001018 with JCAM
  37. IPN TRIANGULATION OF GRB010115
  38. IPN TRIANGULATION OF GRB010109
  39. IPN TRIANGULATION OF GRB010109
  40. GRB010103, optical observations
  41. IPN triangulation of GRB010104
  42. IPN triangulation of GRB010103
  43. GRB 001204: Ks observations
  44. H band observation of GRB 001212
  45. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  46. IPN triangulation of GRB001219
  47. GRB 001212 Optical Observation
  48. GRB 001212 Optical Observation
  49. GRB 001212 optical observation
  50. GRB 001212 possible OA in 2MASS
  51. GRB 001212 possible OA
  52. IPN triangulation of GRB001212
  53. GRB001204: Optical observations
  54. Confirmation of IPN position for GRB001204
  55. GRB001204, Radio observations
  56. IPN triangulation of GRB001204 (short/hard)
  57. GRB 001105, further optical observations
  58. GRB001120: Gunn-i observations
  59. GRB001120: Optical observations
  60. GRB001109, optical observations
  61. GRB001120, optical observations
  62. WSRT 4.8 GHz observations of GRB001109
  63. IPN triangulation of GRB001120
  64. Optical/NIR observations of GRB001109
  65. GRB 001109: deep JHK upper limits
  66. GRB 001109 X-ray afterglow with BeppoSAX
  67. CORRECTION to XMM-Newton observation of GRB001025
  68. GRB001109: Optical observations
  69. GRB001109: BeppoSAX/NFI Observations
  70. GRB001109, R-band optical observations
  71. GRB001109, Radio observations
  72. GRB001109: BeppoSAX refined WFC position
  73. BeppoSAX ALERT: GRB001109
  74. GRB001105 BVRI field photometry correction
  75. GRB001105, BVRI field photometry
  76. GRB 001105, R-band observation
  77. IPN TRIANGULATION OF GRB001105
  78. GRB 001025B, Optical obervations
  79. GRB 991208: HST Imaging of the Host Galaxy
  80. GRB000926: R-image of the host galaxy
  81. GRB 001025B, I-band observations
  82. XMM-Newton observation of GRB001025
  83. GRB001025B, Radio observations
  84. GRB 001025 Optical Observations
  85. GRB 001025A, optical observation
  86. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  87. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  88. IPN triangulation of GRB001025
  89. GRB001007: Optical observations
  90. ASM Localization of GRB 001025
  91. GRB001007, Radio observations
  92. IPN TRIANGULATION OF GRB001020
  93. GRB001019, Optical Observations
  94. GRB 001018, Possible Radio Afterglow
  95. GRB001018, Gamma Ray Observations
  96. IPN TRIANGULATION OF GRB001019
  97. CORRECTION TO PEAK FLUX OF GRB001018
  98. IPN TRIANGULATION OF GRB001018
  99. IPN TRIANGULATION OF GRB 001017
  100. GRB 000926: Improved Absorber Redshift

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