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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 refined WFC position
  2. BeppoSAX ALERT: GRB010214
  3. IPN Status Report
  4. HETE Status
  5. GRB010126 opt. obs.
  6. IPN/RXTE TRIANGULATION OF GRB010126
  7. GRB010126: CONCAM crude optical limits during GRB
  8. GRB010126, TNG R-band observations
  9. GRB010126 Optical Observations
  10. GRB010126 optical observations
  11. GRB010126: Optical observations
  12. IPN TRIANGULATION OF GRB010126
  13. IPN/RXTE TRIANGULATION OF GRB010126
  14. GRB 010119, optical observations
  15. GRB010119: Optical observations
  16. Optical Observations of GRB 001018 at Keck
  17. GRB010119, Radio observations
  18. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  19. Optical observations of GRB 001018 with JCAM
  20. IPN TRIANGULATION OF GRB010115
  21. IPN TRIANGULATION OF GRB010109
  22. IPN TRIANGULATION OF GRB010109
  23. GRB010103, optical observations
  24. IPN triangulation of GRB010104
  25. IPN triangulation of GRB010103
  26. GRB 001204: Ks observations
  27. H band observation of GRB 001212
  28. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  29. IPN triangulation of GRB001219
  30. GRB 001212 Optical Observation
  31. GRB 001212 Optical Observation
  32. GRB 001212 optical observation
  33. GRB 001212 possible OA in 2MASS
  34. GRB 001212 possible OA
  35. IPN triangulation of GRB001212
  36. GRB001204: Optical observations
  37. Confirmation of IPN position for GRB001204
  38. GRB001204, Radio observations
  39. IPN triangulation of GRB001204 (short/hard)
  40. GRB 001105, further optical observations
  41. GRB001120: Gunn-i observations
  42. GRB001120: Optical observations
  43. GRB001109, optical observations
  44. GRB001120, optical observations
  45. WSRT 4.8 GHz observations of GRB001109
  46. IPN triangulation of GRB001120
  47. Optical/NIR observations of GRB001109
  48. GRB 001109: deep JHK upper limits
  49. GRB 001109 X-ray afterglow with BeppoSAX
  50. CORRECTION to XMM-Newton observation of GRB001025
  51. GRB001109: Optical observations
  52. GRB001109: BeppoSAX/NFI Observations
  53. GRB001109, R-band optical observations
  54. GRB001109, Radio observations
  55. GRB001109: BeppoSAX refined WFC position
  56. BeppoSAX ALERT: GRB001109
  57. GRB001105 BVRI field photometry correction
  58. GRB001105, BVRI field photometry
  59. GRB 001105, R-band observation
  60. IPN TRIANGULATION OF GRB001105
  61. GRB 001025B, Optical obervations
  62. GRB 991208: HST Imaging of the Host Galaxy
  63. GRB000926: R-image of the host galaxy
  64. GRB 001025B, I-band observations
  65. XMM-Newton observation of GRB001025
  66. GRB001025B, Radio observations
  67. GRB 001025 Optical Observations
  68. GRB 001025A, optical observation
  69. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  70. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  71. IPN triangulation of GRB001025
  72. GRB001007: Optical observations
  73. ASM Localization of GRB 001025
  74. GRB001007, Radio observations
  75. IPN TRIANGULATION OF GRB001020
  76. GRB001019, Optical Observations
  77. GRB 001018, Possible Radio Afterglow
  78. GRB001018, Gamma Ray Observations
  79. IPN TRIANGULATION OF GRB001019
  80. CORRECTION TO PEAK FLUX OF GRB001018
  81. IPN TRIANGULATION OF GRB001018
  82. IPN TRIANGULATION OF GRB 001017
  83. GRB 000926: Improved Absorber Redshift
  84. V,R,I band observations of GRB000926
  85. The Likely Optical/Infrared Afterglow of GRB 001011
  86. HETE positions added to GCN
  87. GRB001011 BeppoSAX/WFC refined position
  88. BeppoSAX ALERT: GRB001011
  89. GRB 001007, BVR-band observations
  90. GRB000926 - Amateur Optical Observations
  91. GRB001007: Optical observations
  92. CONCAM null result on GRB001005
  93. IPN triangulation of GRB001007
  94. GRB 000926 : the host galaxy
  95. HETE-2 Launches Successfully
  96. IPN triangulation of GRB001005
  97. HETE-2 48 hour Launch Delay
  98. GRB 000926 Chandra Observation
  99. IPN triangulation of GRB 001004
  100. Public availability of BeppoSAX data of GRB000926

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