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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. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  2. VLT spectrum of GRB990712
  3. GRB 990712
  4. Late-time HST/STIS Observations of GRB 990510
  5. Refined BeppoSAX-WFC position of GRB990712
  6. BeppoSAX NFI Observation of GRB990705
  7. BeppoSAX NFI Observation of GRB990705
  8. Updated Astrometry for the IR Counterpart of GRB990705
  9. GRB 990705, R-band observations
  10. Updated IPN localization of GRB990705
  11. IPN localization of GRB990704
  12. IPN localization of GRB990705
  13. Infrared and Optical Observations of GRB990705
  14. GRB 990705, radio observations
  15. GRB990704: SAX-NFI results summary
  16. GRB990704 radio and optical observations
  17. BeppoSAX GRB990705: possible X-ray afterglow
  18. GRB 990704 X-ray Observations
  19. GRB 990704 Optical Observations
  20. GRB 990704, optical observations
  21. GRB990704
  22. GRB990705: Intriguing Positional Coincidences
  23. GRB990704
  24. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  25. GRB990704, optical observations
  26. GRB990704: possible X-ray afterglow
  27. Identification of a possible optical counterpart for GRB990704
  28. GRB990704
  29. Refined BeppoSAX-WFC position of GRB990704
  30. GRB990704: BeppoSAX detection
  31. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  32. Optical Observations of GRB990627
  33. GRB 990627, radio observations
  34. GRB990627: BeppoSAX-WFC final location
  35. BeppoSAX: GRB990625
  36. Late-time HST/STIS Observation of GRB 990123
  37. GRB 990506 - clarification to GCN 352
  38. GRB 990506 - Optical Observations
  39. Optical Observations of GRB 990506
  40. GRB 990506 Radio Transient
  41. GRB990527 Optical Observations
  42. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  43. IPN error box for GRB990527
  44. Late Afterglows of GRBs 990510, 990123
  45. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  46. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  47. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  48. GRB 990506 optical observation
  49. X-ray/GRB 1SAX J0835.9+5118, 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. radio observations of X-ray/GRB transient field
  54. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  55. Optical report on X-ray/GRB transient
  56. radio detection of X-ray/GRB transient
  57. BeppoSAX: A new fast X-ray transient
  58. GRB 990510: optical observations
  59. GRB990510: photometric and spectroscopic observations with the VLT
  60. GRB 990510: optical linear polarization
  61. GRB 990510: optical observations
  62. GRB990510, VI observations
  63. GRB 990506 R band observations
  64. GRB990510: X-ray afterglow
  65. GRB 990510: optical observation
  66. VLT spectrum of GRB990510
  67. GRB 990510: Broad Band Break
  68. GRB 990510: BATSE Observations
  69. GRB990510: optical observation
  70. GRB 990510 Optical Observations
  71. GRB 990510, BVI photometry
  72. GRB 990510 optical observations
  73. GRB 990510: BeppoSAX/GRBM observations
  74. GRB990510 optical observations
  75. GRB990510
  76. GRB 990510 optical observations
  77. GRB 990510 optical observations
  78. Galactic extinction towards GRB 990510
  79. GRB990510: NFI X-ray source
  80. GRB 990510 optical observations
  81. IPN localization of GRB990510
  82. GRB 990506 Radio Observations
  83. GRB 990123, optical monitoring
  84. GRB 990506: BATSE Observations
  85. GRB 990506, optical observations
  86. GRB 990510: Final BeppoSAX-WFC Coordinates
  87. GRB 990506, Optical Observations
  88. GRB 990506 optical observations
  89. GRB 990506 optical observations
  90. GRB 990506, optical observations
  91. GRB990506 observation plan
  92. Refined IPN error box for GRB990506
  93. GRB 990506: Limits on the possible optical transient
  94. GRB 990506, armchair astronomy
  95. GRB 990506, optical observations from +1 to +3 hours
  96. GRB 990506, optical observations
  97. GRB990506 Optical observations
  98. GRB990506 observation plan
  99. New IPN/RXTE error box for GRB990506
  100. IPN localization for GRB990506

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