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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. GRB010214, optical observations
  2. GRB010213, optical observations
  3. GRB010213, Near-IR observations
  4. Possible InfraRed Transient of GRB 010214.
  5. GRB010214 Optical Observation
  6. GRB010214: BeppoSAX/NFI Observations
  7. GRB010213 (HETE) TAROT observations
  8. GRB 010214, optical observations
  9. GRB010213 detected by HETE
  10. GRB010214 refined WFC position
  11. BeppoSAX ALERT: GRB010214
  12. IPN Status Report
  13. HETE Status
  14. GRB010126 opt. obs.
  15. IPN/RXTE TRIANGULATION OF GRB010126
  16. GRB010126: CONCAM crude optical limits during GRB
  17. GRB010126, TNG R-band observations
  18. GRB010126 Optical Observations
  19. GRB010126 optical observations
  20. GRB010126: Optical observations
  21. IPN TRIANGULATION OF GRB010126
  22. IPN/RXTE TRIANGULATION OF GRB010126
  23. GRB 010119, optical observations
  24. GRB010119: Optical observations
  25. Optical Observations of GRB 001018 at Keck
  26. GRB010119, Radio observations
  27. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  28. Optical observations of GRB 001018 with JCAM
  29. IPN TRIANGULATION OF GRB010115
  30. IPN TRIANGULATION OF GRB010109
  31. IPN TRIANGULATION OF GRB010109
  32. GRB010103, optical observations
  33. IPN triangulation of GRB010104
  34. IPN triangulation of GRB010103
  35. GRB 001204: Ks observations
  36. H band observation of GRB 001212
  37. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  38. IPN triangulation of GRB001219
  39. GRB 001212 Optical Observation
  40. GRB 001212 Optical Observation
  41. GRB 001212 optical observation
  42. GRB 001212 possible OA in 2MASS
  43. GRB 001212 possible OA
  44. IPN triangulation of GRB001212
  45. GRB001204: Optical observations
  46. Confirmation of IPN position for GRB001204
  47. GRB001204, Radio observations
  48. IPN triangulation of GRB001204 (short/hard)
  49. GRB 001105, further optical observations
  50. GRB001120: Gunn-i observations
  51. GRB001120: Optical observations
  52. GRB001109, optical observations
  53. GRB001120, optical observations
  54. WSRT 4.8 GHz observations of GRB001109
  55. IPN triangulation of GRB001120
  56. Optical/NIR observations of GRB001109
  57. GRB 001109: deep JHK upper limits
  58. GRB 001109 X-ray afterglow with BeppoSAX
  59. CORRECTION to XMM-Newton observation of GRB001025
  60. GRB001109: Optical observations
  61. GRB001109: BeppoSAX/NFI Observations
  62. GRB001109, R-band optical observations
  63. GRB001109, Radio observations
  64. GRB001109: BeppoSAX refined WFC position
  65. BeppoSAX ALERT: GRB001109
  66. GRB001105 BVRI field photometry correction
  67. GRB001105, BVRI field photometry
  68. GRB 001105, R-band observation
  69. IPN TRIANGULATION OF GRB001105
  70. GRB 001025B, Optical obervations
  71. GRB 991208: HST Imaging of the Host Galaxy
  72. GRB000926: R-image of the host galaxy
  73. GRB 001025B, I-band observations
  74. XMM-Newton observation of GRB001025
  75. GRB001025B, Radio observations
  76. GRB 001025 Optical Observations
  77. GRB 001025A, optical observation
  78. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  79. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  80. IPN triangulation of GRB001025
  81. GRB001007: Optical observations
  82. ASM Localization of GRB 001025
  83. GRB001007, Radio observations
  84. IPN TRIANGULATION OF GRB001020
  85. GRB001019, Optical Observations
  86. GRB 001018, Possible Radio Afterglow
  87. GRB001018, Gamma Ray Observations
  88. IPN TRIANGULATION OF GRB001019
  89. CORRECTION TO PEAK FLUX OF GRB001018
  90. IPN TRIANGULATION OF GRB001018
  91. IPN TRIANGULATION OF GRB 001017
  92. GRB 000926: Improved Absorber Redshift
  93. V,R,I band observations of GRB000926
  94. The Likely Optical/Infrared Afterglow of GRB 001011
  95. HETE positions added to GCN
  96. GRB001011 BeppoSAX/WFC refined position
  97. BeppoSAX ALERT: GRB001011
  98. GRB 001007, BVR-band observations
  99. GRB000926 - Amateur Optical Observations
  100. GRB001007: Optical observations

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