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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. Refined BeppoSAX-WFC position of GRB990704
  2. GRB990704: BeppoSAX detection
  3. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  4. Optical Observations of GRB990627
  5. GRB 990627, radio observations
  6. GRB990627: BeppoSAX-WFC final location
  7. BeppoSAX: GRB990625
  8. Late-time HST/STIS Observation of GRB 990123
  9. GRB 990506 - clarification to GCN 352
  10. GRB 990506 - Optical Observations
  11. Optical Observations of GRB 990506
  12. GRB 990506 Radio Transient
  13. GRB990527 Optical Observations
  14. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  15. IPN error box for GRB990527
  16. Late Afterglows of GRBs 990510, 990123
  17. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  18. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  19. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  20. GRB 990506 optical observation
  21. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  22. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  23. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  24. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  25. radio observations of X-ray/GRB transient field
  26. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  27. Optical report on X-ray/GRB transient
  28. radio detection of X-ray/GRB transient
  29. BeppoSAX: A new fast X-ray transient
  30. GRB 990510: optical observations
  31. GRB990510: photometric and spectroscopic observations with the VLT
  32. GRB 990510: optical linear polarization
  33. GRB 990510: optical observations
  34. GRB990510, VI observations
  35. GRB 990506 R band observations
  36. GRB990510: X-ray afterglow
  37. GRB 990510: optical observation
  38. VLT spectrum of GRB990510
  39. GRB 990510: Broad Band Break
  40. GRB 990510: BATSE Observations
  41. GRB990510: optical observation
  42. GRB 990510 Optical Observations
  43. GRB 990510, BVI photometry
  44. GRB 990510 optical observations
  45. GRB 990510: BeppoSAX/GRBM observations
  46. GRB990510 optical observations
  47. GRB990510
  48. GRB 990510 optical observations
  49. GRB 990510 optical observations
  50. Galactic extinction towards GRB 990510
  51. GRB990510: NFI X-ray source
  52. GRB 990510 optical observations
  53. IPN localization of GRB990510
  54. GRB 990506 Radio Observations
  55. GRB 990123, optical monitoring
  56. GRB 990506: BATSE Observations
  57. GRB 990506, optical observations
  58. GRB 990510: Final BeppoSAX-WFC Coordinates
  59. GRB 990506, Optical Observations
  60. GRB 990506 optical observations
  61. GRB 990506 optical observations
  62. GRB 990506, optical observations
  63. GRB990506 observation plan
  64. Refined IPN error box for GRB990506
  65. GRB 990506: Limits on the possible optical transient
  66. GRB 990506, armchair astronomy
  67. GRB 990506, optical observations from +1 to +3 hours
  68. GRB 990506, optical observations
  69. GRB990506 Optical observations
  70. GRB990506 observation plan
  71. New IPN/RXTE error box for GRB990506
  72. IPN localization for GRB990506
  73. GRB 970228: Redshift and properties of the host galaxy
  74. IPN localization of GRB990427
  75. GRB981220 VLBA observations
  76. GRB980425 Optical observations of exponential decline at late time
  77. GRB990321 REFINED IPN ANNULUS
  78. GRB990323 PRECISE IPN POSITION
  79. GRB990321 IPN TRIANGULATION
  80. GRB 990316 Optical Observations
  81. GRB 990316, Radio observations
  82. GRB 990316, Optical observations
  83. GRB990316, Optical observations
  84. GRB 990316 optical observations
  85. GRB990316: simultaneous optical observation
  86. GRB990316 - Optical null results
  87. ASM/IPN error box for GRB 990308 (BATSE #7457)
  88. GRB990308 not a new SGR
  89. GRB 990308a and GRB 990308b
  90. GRB990308 (Trig. 7457), optical observations
  91. GRB990308, Possible new SGR~0209+70
  92. GRB981220, IPN localization
  93. GRB 981220, radio observations
  94. GRB 990123, Field Photometry
  95. GRB 990217 Optical Observations
  96. GRB 990217, radio observations
  97. BATSE Resumes Normal Operations
  98. BATSE Flight Anomaly
  99. GRB990217: BeppoSAX/GRBM data
  100. Optical Observations of GRB990217

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