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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. IPN TRIANGULATION OF GRB010126
  2. IPN/RXTE TRIANGULATION OF GRB010126
  3. GRB 010119, optical observations
  4. GRB010119: Optical observations
  5. Optical Observations of GRB 001018 at Keck
  6. GRB010119, Radio observations
  7. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  8. Optical observations of GRB 001018 with JCAM
  9. IPN TRIANGULATION OF GRB010115
  10. IPN TRIANGULATION OF GRB010109
  11. IPN TRIANGULATION OF GRB010109
  12. GRB010103, optical observations
  13. IPN triangulation of GRB010104
  14. IPN triangulation of GRB010103
  15. GRB 001204: Ks observations
  16. H band observation of GRB 001212
  17. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  18. IPN triangulation of GRB001219
  19. GRB 001212 Optical Observation
  20. GRB 001212 Optical Observation
  21. GRB 001212 optical observation
  22. GRB 001212 possible OA in 2MASS
  23. GRB 001212 possible OA
  24. IPN triangulation of GRB001212
  25. GRB001204: Optical observations
  26. Confirmation of IPN position for GRB001204
  27. GRB001204, Radio observations
  28. IPN triangulation of GRB001204 (short/hard)
  29. GRB 001105, further optical observations
  30. GRB001120: Gunn-i observations
  31. GRB001120: Optical observations
  32. GRB001109, optical observations
  33. GRB001120, optical observations
  34. WSRT 4.8 GHz observations of GRB001109
  35. IPN triangulation of GRB001120
  36. Optical/NIR observations of GRB001109
  37. GRB 001109: deep JHK upper limits
  38. GRB 001109 X-ray afterglow with BeppoSAX
  39. CORRECTION to XMM-Newton observation of GRB001025
  40. GRB001109: Optical observations
  41. GRB001109: BeppoSAX/NFI Observations
  42. GRB001109, R-band optical observations
  43. GRB001109, Radio observations
  44. GRB001109: BeppoSAX refined WFC position
  45. BeppoSAX ALERT: GRB001109
  46. GRB001105 BVRI field photometry correction
  47. GRB001105, BVRI field photometry
  48. GRB 001105, R-band observation
  49. IPN TRIANGULATION OF GRB001105
  50. GRB 001025B, Optical obervations
  51. GRB 991208: HST Imaging of the Host Galaxy
  52. GRB000926: R-image of the host galaxy
  53. GRB 001025B, I-band observations
  54. XMM-Newton observation of GRB001025
  55. GRB001025B, Radio observations
  56. GRB 001025 Optical Observations
  57. GRB 001025A, optical observation
  58. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  59. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  60. IPN triangulation of GRB001025
  61. GRB001007: Optical observations
  62. ASM Localization of GRB 001025
  63. GRB001007, Radio observations
  64. IPN TRIANGULATION OF GRB001020
  65. GRB001019, Optical Observations
  66. GRB 001018, Possible Radio Afterglow
  67. GRB001018, Gamma Ray Observations
  68. IPN TRIANGULATION OF GRB001019
  69. CORRECTION TO PEAK FLUX OF GRB001018
  70. IPN TRIANGULATION OF GRB001018
  71. IPN TRIANGULATION OF GRB 001017
  72. GRB 000926: Improved Absorber Redshift
  73. V,R,I band observations of GRB000926
  74. The Likely Optical/Infrared Afterglow of GRB 001011
  75. HETE positions added to GCN
  76. GRB001011 BeppoSAX/WFC refined position
  77. BeppoSAX ALERT: GRB001011
  78. GRB 001007, BVR-band observations
  79. GRB000926 - Amateur Optical Observations
  80. GRB001007: Optical observations
  81. CONCAM null result on GRB001005
  82. IPN triangulation of GRB001007
  83. GRB 000926 : the host galaxy
  84. HETE-2 Launches Successfully
  85. IPN triangulation of GRB001005
  86. HETE-2 48 hour Launch Delay
  87. GRB 000926 Chandra Observation
  88. IPN triangulation of GRB 001004
  89. Public availability of BeppoSAX data of GRB000926
  90. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  91. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  92. GRB000926 - Optical observations
  93. GRB000926 - Optical observations
  94. GRB 000926, Optical Decay
  95. GRB000911: VLT infrared observation
  96. GRB000926 - Optical observations
  97. GRB000926 - Optical observations
  98. GRB 000926: optical observations
  99. GRB 000926, Optical Observations
  100. GRB000926 - Optical observations

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