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

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