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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. VLT spectrum of GRB990712
  2. GRB 990712
  3. Late-time HST/STIS Observations of GRB 990510
  4. Refined BeppoSAX-WFC position of GRB990712
  5. BeppoSAX NFI Observation of GRB990705
  6. BeppoSAX NFI Observation of GRB990705
  7. Updated Astrometry for the IR Counterpart of GRB990705
  8. GRB 990705, R-band observations
  9. Updated IPN localization of GRB990705
  10. IPN localization of GRB990704
  11. IPN localization of GRB990705
  12. Infrared and Optical Observations of GRB990705
  13. GRB 990705, radio observations
  14. GRB990704: SAX-NFI results summary
  15. GRB990704 radio and optical observations
  16. BeppoSAX GRB990705: possible X-ray afterglow
  17. GRB 990704 X-ray Observations
  18. GRB 990704 Optical Observations
  19. GRB 990704, optical observations
  20. GRB990704
  21. GRB990705: Intriguing Positional Coincidences
  22. GRB990704
  23. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  24. GRB990704, optical observations
  25. GRB990704: possible X-ray afterglow
  26. Identification of a possible optical counterpart for GRB990704
  27. GRB990704
  28. Refined BeppoSAX-WFC position of GRB990704
  29. GRB990704: BeppoSAX detection
  30. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  31. Optical Observations of GRB990627
  32. GRB 990627, radio observations
  33. GRB990627: BeppoSAX-WFC final location
  34. BeppoSAX: GRB990625
  35. Late-time HST/STIS Observation of GRB 990123
  36. GRB 990506 - clarification to GCN 352
  37. GRB 990506 - Optical Observations
  38. Optical Observations of GRB 990506
  39. GRB 990506 Radio Transient
  40. GRB990527 Optical Observations
  41. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  42. IPN error box for GRB990527
  43. Late Afterglows of GRBs 990510, 990123
  44. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  45. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  46. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  47. GRB 990506 optical observation
  48. X-ray/GRB 1SAX J0835.9+5118, 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. radio observations of X-ray/GRB transient field
  53. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  54. Optical report on X-ray/GRB transient
  55. radio detection of X-ray/GRB transient
  56. BeppoSAX: A new fast X-ray transient
  57. GRB 990510: optical observations
  58. GRB990510: photometric and spectroscopic observations with the VLT
  59. GRB 990510: optical linear polarization
  60. GRB 990510: optical observations
  61. GRB990510, VI observations
  62. GRB 990506 R band observations
  63. GRB990510: X-ray afterglow
  64. GRB 990510: optical observation
  65. VLT spectrum of GRB990510
  66. GRB 990510: Broad Band Break
  67. GRB 990510: BATSE Observations
  68. GRB990510: optical observation
  69. GRB 990510 Optical Observations
  70. GRB 990510, BVI photometry
  71. GRB 990510 optical observations
  72. GRB 990510: BeppoSAX/GRBM observations
  73. GRB990510 optical observations
  74. GRB990510
  75. GRB 990510 optical observations
  76. GRB 990510 optical observations
  77. Galactic extinction towards GRB 990510
  78. GRB990510: NFI X-ray source
  79. GRB 990510 optical observations
  80. IPN localization of GRB990510
  81. GRB 990506 Radio Observations
  82. GRB 990123, optical monitoring
  83. GRB 990506: BATSE Observations
  84. GRB 990506, optical observations
  85. GRB 990510: Final BeppoSAX-WFC Coordinates
  86. GRB 990506, Optical Observations
  87. GRB 990506 optical observations
  88. GRB 990506 optical observations
  89. GRB 990506, optical observations
  90. GRB990506 observation plan
  91. Refined IPN error box for GRB990506
  92. GRB 990506: Limits on the possible optical transient
  93. GRB 990506, armchair astronomy
  94. GRB 990506, optical observations from +1 to +3 hours
  95. GRB 990506, optical observations
  96. GRB990506 Optical observations
  97. GRB990506 observation plan
  98. New IPN/RXTE error box for GRB990506
  99. IPN localization for GRB990506
  100. GRB 970228: Redshift and properties of the host galaxy

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