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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"

44977 results found.

  1. GRB 990704 X-ray Observations
  2. GRB 990704 Optical Observations
  3. GRB 990704, optical observations
  4. GRB990704
  5. GRB990705: Intriguing Positional Coincidences
  6. GRB990704
  7. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  8. GRB990704, optical observations
  9. GRB990704: possible X-ray afterglow
  10. Identification of a possible optical counterpart for GRB990704
  11. GRB990704
  12. Refined BeppoSAX-WFC position of GRB990704
  13. GRB990704: BeppoSAX detection
  14. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  15. Optical Observations of GRB990627
  16. GRB 990627, radio observations
  17. GRB990627: BeppoSAX-WFC final location
  18. BeppoSAX: GRB990625
  19. Late-time HST/STIS Observation of GRB 990123
  20. GRB 990506 - clarification to GCN 352
  21. GRB 990506 - Optical Observations
  22. Optical Observations of GRB 990506
  23. GRB 990506 Radio Transient
  24. GRB990527 Optical Observations
  25. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  26. IPN error box for GRB990527
  27. Late Afterglows of GRBs 990510, 990123
  28. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  29. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  30. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  31. GRB 990506 optical observation
  32. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  33. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  34. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  35. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  36. radio observations of X-ray/GRB transient field
  37. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  38. Optical report on X-ray/GRB transient
  39. radio detection of X-ray/GRB transient
  40. BeppoSAX: A new fast X-ray transient
  41. GRB 990510: optical observations
  42. GRB990510: photometric and spectroscopic observations with the VLT
  43. GRB 990510: optical linear polarization
  44. GRB 990510: optical observations
  45. GRB990510, VI observations
  46. GRB 990506 R band observations
  47. GRB990510: X-ray afterglow
  48. GRB 990510: optical observation
  49. VLT spectrum of GRB990510
  50. GRB 990510: Broad Band Break
  51. GRB 990510: BATSE Observations
  52. GRB990510: optical observation
  53. GRB 990510 Optical Observations
  54. GRB 990510, BVI photometry
  55. GRB 990510 optical observations
  56. GRB 990510: BeppoSAX/GRBM observations
  57. GRB990510 optical observations
  58. GRB990510
  59. GRB 990510 optical observations
  60. GRB 990510 optical observations
  61. Galactic extinction towards GRB 990510
  62. GRB990510: NFI X-ray source
  63. GRB 990510 optical observations
  64. IPN localization of GRB990510
  65. GRB 990506 Radio Observations
  66. GRB 990123, optical monitoring
  67. GRB 990506: BATSE Observations
  68. GRB 990506, optical observations
  69. GRB 990510: Final BeppoSAX-WFC Coordinates
  70. GRB 990506, Optical Observations
  71. GRB 990506 optical observations
  72. GRB 990506 optical observations
  73. GRB 990506, optical observations
  74. GRB990506 observation plan
  75. Refined IPN error box for GRB990506
  76. GRB 990506: Limits on the possible optical transient
  77. GRB 990506, armchair astronomy
  78. GRB 990506, optical observations from +1 to +3 hours
  79. GRB 990506, optical observations
  80. GRB990506 Optical observations
  81. GRB990506 observation plan
  82. New IPN/RXTE error box for GRB990506
  83. IPN localization for GRB990506
  84. GRB 970228: Redshift and properties of the host galaxy
  85. IPN localization of GRB990427
  86. GRB981220 VLBA observations
  87. GRB980425 Optical observations of exponential decline at late time
  88. GRB990321 REFINED IPN ANNULUS
  89. GRB990323 PRECISE IPN POSITION
  90. GRB990321 IPN TRIANGULATION
  91. GRB 990316 Optical Observations
  92. GRB 990316, Radio observations
  93. GRB 990316, Optical observations
  94. GRB990316, Optical observations
  95. GRB 990316 optical observations
  96. GRB990316: simultaneous optical observation
  97. GRB990316 - Optical null results
  98. ASM/IPN error box for GRB 990308 (BATSE #7457)
  99. GRB990308 not a new SGR
  100. GRB 990308a and GRB 990308b

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