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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"

40643 results found.

  1. GRB 990704, optical observations
  2. GRB990705: Intriguing Positional Coincidences
  3. GRB990704
  4. GRB990704, optical observations
  5. Identification of a possible optical counterpart for GRB990704
  6. GRB990704
  7. Refined BeppoSAX-WFC position of GRB990704
  8. GRB990704: BeppoSAX detection
  9. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  10. Optical Observations of GRB990627
  11. GRB 990627, radio observations
  12. BeppoSAX: GRB990625
  13. Late-time HST/STIS Observation of GRB 990123
  14. GRB 990506 - clarification to GCN 352
  15. GRB 990506 - Optical Observations
  16. Optical Observations of GRB 990506
  17. GRB990527 Optical Observations
  18. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  19. IPN error box for GRB990527
  20. Late Afterglows of GRBs 990510, 990123
  21. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  22. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  23. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  24. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  25. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  26. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  27. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  28. radio observations of X-ray/GRB transient field
  29. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  30. Optical report on X-ray/GRB transient
  31. radio detection of X-ray/GRB transient
  32. BeppoSAX: A new fast X-ray transient
  33. GRB 990510: optical observations
  34. GRB990510: photometric and spectroscopic observations with the VLT
  35. GRB 990510: optical linear polarization
  36. GRB 990510: optical observations
  37. GRB990510, VI observations
  38. GRB 990506 R band observations
  39. GRB990510: X-ray afterglow
  40. GRB 990510: optical observation
  41. VLT spectrum of GRB990510
  42. GRB 990510: Broad Band Break
  43. GRB 990510: BATSE Observations
  44. GRB990510: optical observation
  45. GRB 990510 Optical Observations
  46. GRB 990510, BVI photometry
  47. GRB 990510 optical observations
  48. GRB 990510: BeppoSAX/GRBM observations
  49. GRB990510 optical observations
  50. GRB990510
  51. GRB 990510 optical observations
  52. GRB 990510 optical observations
  53. GRB 990510 optical observations
  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. IPN localization for GRB990506
  72. GRB 970228: Redshift and properties of the host galaxy
  73. GRB981220 VLBA observations
  74. GRB980425 Optical observations of exponential decline at late time
  75. GRB990323 PRECISE IPN POSITION
  76. GRB990321 IPN TRIANGULATION
  77. GRB 990316 Optical Observations
  78. GRB 990316, Radio observations
  79. GRB 990316, Optical observations
  80. GRB990316, Optical observations
  81. GRB 990316 optical observations
  82. GRB990316: simultaneous optical observation
  83. ASM/IPN error box for GRB 990308 (BATSE #7457)
  84. GRB990308 not a new SGR
  85. GRB 990308a and GRB 990308b
  86. GRB990308 (Trig. 7457), optical observations
  87. GRB990308, Possible new SGR~0209+70
  88. GRB981220, IPN localization
  89. GRB 981220, radio observations
  90. GRB 990123, Field Photometry
  91. GRB 990217 Optical Observations
  92. GRB 990217, radio observations
  93. BATSE Resumes Normal Operations
  94. GRB990217: BeppoSAX/GRBM data
  95. Optical Observations of GRB990217
  96. GRB990123 observations
  97. GRB990217 Optical observation
  98. GRB990217, WFC position
  99. GRB990123, Optical Observation
  100. GRB 990123: Discovery of the Probable Host Galaxy

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