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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. GRB990705: No Evidence for Neutrino Signal
  2. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  3. VLT spectrum of GRB990712
  4. GRB 990712
  5. Late-time HST/STIS Observations of GRB 990510
  6. Refined BeppoSAX-WFC position of GRB990712
  7. BeppoSAX NFI Observation of GRB990705
  8. BeppoSAX NFI Observation of GRB990705
  9. Updated Astrometry for the IR Counterpart of GRB990705
  10. GRB 990705, R-band observations
  11. Updated IPN localization of GRB990705
  12. IPN localization of GRB990704
  13. IPN localization of GRB990705
  14. Infrared and Optical Observations of GRB990705
  15. GRB 990705, radio observations
  16. GRB990704: SAX-NFI results summary
  17. GRB990704 radio and optical observations
  18. BeppoSAX GRB990705: possible X-ray afterglow
  19. GRB 990704 X-ray Observations
  20. GRB 990704 Optical Observations
  21. GRB 990704, optical observations
  22. GRB990704
  23. GRB990705: Intriguing Positional Coincidences
  24. GRB990704
  25. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  26. GRB990704, optical observations
  27. GRB990704: possible X-ray afterglow
  28. Identification of a possible optical counterpart for GRB990704
  29. GRB990704
  30. Refined BeppoSAX-WFC position of GRB990704
  31. GRB990704: BeppoSAX detection
  32. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  33. Optical Observations of GRB990627
  34. GRB 990627, radio observations
  35. GRB990627: BeppoSAX-WFC final location
  36. BeppoSAX: GRB990625
  37. Late-time HST/STIS Observation of GRB 990123
  38. GRB 990506 - clarification to GCN 352
  39. GRB 990506 - Optical Observations
  40. Optical Observations of GRB 990506
  41. GRB 990506 Radio Transient
  42. GRB990527 Optical Observations
  43. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  44. IPN error box for GRB990527
  45. Late Afterglows of GRBs 990510, 990123
  46. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  47. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  48. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  49. GRB 990506 optical observation
  50. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  51. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  52. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  53. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  54. radio observations of X-ray/GRB transient field
  55. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  56. Optical report on X-ray/GRB transient
  57. radio detection of X-ray/GRB transient
  58. BeppoSAX: A new fast X-ray transient
  59. GRB 990510: optical observations
  60. GRB990510: photometric and spectroscopic observations with the VLT
  61. GRB 990510: optical linear polarization
  62. GRB 990510: optical observations
  63. GRB990510, VI observations
  64. GRB 990506 R band observations
  65. GRB990510: X-ray afterglow
  66. GRB 990510: optical observation
  67. VLT spectrum of GRB990510
  68. GRB 990510: Broad Band Break
  69. GRB 990510: BATSE Observations
  70. GRB990510: optical observation
  71. GRB 990510 Optical Observations
  72. GRB 990510, BVI photometry
  73. GRB 990510 optical observations
  74. GRB 990510: BeppoSAX/GRBM observations
  75. GRB990510 optical observations
  76. GRB990510
  77. GRB 990510 optical observations
  78. GRB 990510 optical observations
  79. Galactic extinction towards GRB 990510
  80. GRB990510: NFI X-ray source
  81. GRB 990510 optical observations
  82. IPN localization of GRB990510
  83. GRB 990506 Radio Observations
  84. GRB 990123, optical monitoring
  85. GRB 990506: BATSE Observations
  86. GRB 990506, optical observations
  87. GRB 990510: Final BeppoSAX-WFC Coordinates
  88. GRB 990506, Optical Observations
  89. GRB 990506 optical observations
  90. GRB 990506 optical observations
  91. GRB 990506, optical observations
  92. GRB990506 observation plan
  93. Refined IPN error box for GRB990506
  94. GRB 990506: Limits on the possible optical transient
  95. GRB 990506, armchair astronomy
  96. GRB 990506, optical observations from +1 to +3 hours
  97. GRB 990506, optical observations
  98. GRB990506 Optical observations
  99. GRB990506 observation plan
  100. New IPN/RXTE error box for GRB990506

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