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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. IPN localization of GRB990705
  2. Infrared and Optical Observations of GRB990705
  3. GRB 990705, radio observations
  4. GRB990704: SAX-NFI results summary
  5. GRB990704 radio and optical observations
  6. BeppoSAX GRB990705: possible X-ray afterglow
  7. GRB 990704 X-ray Observations
  8. GRB 990704 Optical Observations
  9. GRB 990704, optical observations
  10. GRB990704
  11. GRB990705: Intriguing Positional Coincidences
  12. GRB990704
  13. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  14. GRB990704, optical observations
  15. GRB990704: possible X-ray afterglow
  16. Identification of a possible optical counterpart for GRB990704
  17. GRB990704
  18. Refined BeppoSAX-WFC position of GRB990704
  19. GRB990704: BeppoSAX detection
  20. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  21. Optical Observations of GRB990627
  22. GRB 990627, radio observations
  23. GRB990627: BeppoSAX-WFC final location
  24. BeppoSAX: GRB990625
  25. Late-time HST/STIS Observation of GRB 990123
  26. GRB 990506 - clarification to GCN 352
  27. GRB 990506 - Optical Observations
  28. Optical Observations of GRB 990506
  29. GRB 990506 Radio Transient
  30. GRB990527 Optical Observations
  31. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  32. IPN error box for GRB990527
  33. Late Afterglows of GRBs 990510, 990123
  34. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  35. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  36. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  37. GRB 990506 optical observation
  38. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  39. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  40. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  41. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  42. radio observations of X-ray/GRB transient field
  43. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  44. Optical report on X-ray/GRB transient
  45. radio detection of X-ray/GRB transient
  46. BeppoSAX: A new fast X-ray transient
  47. GRB 990510: optical observations
  48. GRB990510: photometric and spectroscopic observations with the VLT
  49. GRB 990510: optical linear polarization
  50. GRB 990510: optical observations
  51. GRB990510, VI observations
  52. GRB 990506 R band observations
  53. GRB990510: X-ray afterglow
  54. GRB 990510: optical observation
  55. VLT spectrum of GRB990510
  56. GRB 990510: Broad Band Break
  57. GRB 990510: BATSE Observations
  58. GRB990510: optical observation
  59. GRB 990510 Optical Observations
  60. GRB 990510, BVI photometry
  61. GRB 990510 optical observations
  62. GRB 990510: BeppoSAX/GRBM observations
  63. GRB990510 optical observations
  64. GRB990510
  65. GRB 990510 optical observations
  66. GRB 990510 optical observations
  67. Galactic extinction towards GRB 990510
  68. GRB990510: NFI X-ray source
  69. GRB 990510 optical observations
  70. IPN localization of GRB990510
  71. GRB 990506 Radio Observations
  72. GRB 990123, optical monitoring
  73. GRB 990506: BATSE Observations
  74. GRB 990506, optical observations
  75. GRB 990510: Final BeppoSAX-WFC Coordinates
  76. GRB 990506, Optical Observations
  77. GRB 990506 optical observations
  78. GRB 990506 optical observations
  79. GRB 990506, optical observations
  80. GRB990506 observation plan
  81. Refined IPN error box for GRB990506
  82. GRB 990506: Limits on the possible optical transient
  83. GRB 990506, armchair astronomy
  84. GRB 990506, optical observations from +1 to +3 hours
  85. GRB 990506, optical observations
  86. GRB990506 Optical observations
  87. GRB990506 observation plan
  88. New IPN/RXTE error box for GRB990506
  89. IPN localization for GRB990506
  90. GRB 970228: Redshift and properties of the host galaxy
  91. IPN localization of GRB990427
  92. GRB981220 VLBA observations
  93. GRB980425 Optical observations of exponential decline at late time
  94. GRB990321 REFINED IPN ANNULUS
  95. GRB990323 PRECISE IPN POSITION
  96. GRB990321 IPN TRIANGULATION
  97. GRB 990316 Optical Observations
  98. GRB 990316, Radio observations
  99. GRB 990316, Optical observations
  100. GRB990316, Optical observations

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