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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. GRB990704
  2. GRB990705: Intriguing Positional Coincidences
  3. GRB990704
  4. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  5. GRB990704, optical observations
  6. GRB990704: possible X-ray afterglow
  7. Identification of a possible optical counterpart for GRB990704
  8. GRB990704
  9. Refined BeppoSAX-WFC position of GRB990704
  10. GRB990704: BeppoSAX detection
  11. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  12. Optical Observations of GRB990627
  13. GRB 990627, radio observations
  14. GRB990627: BeppoSAX-WFC final location
  15. BeppoSAX: GRB990625
  16. Late-time HST/STIS Observation of GRB 990123
  17. GRB 990506 - clarification to GCN 352
  18. GRB 990506 - Optical Observations
  19. Optical Observations of GRB 990506
  20. GRB 990506 Radio Transient
  21. GRB990527 Optical Observations
  22. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  23. IPN error box for GRB990527
  24. Late Afterglows of GRBs 990510, 990123
  25. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  26. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  27. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  28. GRB 990506 optical observation
  29. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  30. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  31. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  32. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  33. radio observations of X-ray/GRB transient field
  34. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  35. Optical report on X-ray/GRB transient
  36. radio detection of X-ray/GRB transient
  37. BeppoSAX: A new fast X-ray transient
  38. GRB 990510: optical observations
  39. GRB990510: photometric and spectroscopic observations with the VLT
  40. GRB 990510: optical linear polarization
  41. GRB 990510: optical observations
  42. GRB990510, VI observations
  43. GRB 990506 R band observations
  44. GRB990510: X-ray afterglow
  45. GRB 990510: optical observation
  46. VLT spectrum of GRB990510
  47. GRB 990510: Broad Band Break
  48. GRB 990510: BATSE Observations
  49. GRB990510: optical observation
  50. GRB 990510 Optical Observations
  51. GRB 990510, BVI photometry
  52. GRB 990510 optical observations
  53. GRB 990510: BeppoSAX/GRBM observations
  54. GRB990510 optical observations
  55. GRB990510
  56. GRB 990510 optical observations
  57. GRB 990510 optical observations
  58. Galactic extinction towards GRB 990510
  59. GRB990510: NFI X-ray source
  60. GRB 990510 optical observations
  61. IPN localization of GRB990510
  62. GRB 990506 Radio Observations
  63. GRB 990123, optical monitoring
  64. GRB 990506: BATSE Observations
  65. GRB 990506, optical observations
  66. GRB 990510: Final BeppoSAX-WFC Coordinates
  67. GRB 990506, Optical Observations
  68. GRB 990506 optical observations
  69. GRB 990506 optical observations
  70. GRB 990506, optical observations
  71. GRB990506 observation plan
  72. Refined IPN error box for GRB990506
  73. GRB 990506: Limits on the possible optical transient
  74. GRB 990506, armchair astronomy
  75. GRB 990506, optical observations from +1 to +3 hours
  76. GRB 990506, optical observations
  77. GRB990506 Optical observations
  78. GRB990506 observation plan
  79. New IPN/RXTE error box for GRB990506
  80. IPN localization for GRB990506
  81. GRB 970228: Redshift and properties of the host galaxy
  82. IPN localization of GRB990427
  83. GRB981220 VLBA observations
  84. GRB980425 Optical observations of exponential decline at late time
  85. GRB990321 REFINED IPN ANNULUS
  86. GRB990323 PRECISE IPN POSITION
  87. GRB990321 IPN TRIANGULATION
  88. GRB 990316 Optical Observations
  89. GRB 990316, Radio observations
  90. GRB 990316, Optical observations
  91. GRB990316, Optical observations
  92. GRB 990316 optical observations
  93. GRB990316: simultaneous optical observation
  94. GRB990316 - Optical null results
  95. ASM/IPN error box for GRB 990308 (BATSE #7457)
  96. GRB990308 not a new SGR
  97. GRB 990308a and GRB 990308b
  98. GRB990308 (Trig. 7457), optical observations
  99. GRB990308, Possible new SGR~0209+70
  100. GRB981220, IPN localization

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