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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"

42560 results found.

  1. Infrared and Optical Observations of GRB990705
  2. GRB 990705, radio observations
  3. GRB990704: SAX-NFI results summary
  4. BeppoSAX GRB990705: possible X-ray afterglow
  5. GRB 990704 X-ray Observations
  6. GRB 990704 Optical Observations
  7. GRB990704
  8. GRB990705: Intriguing Positional Coincidences
  9. GRB990704
  10. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  11. GRB990704, optical observations
  12. GRB990704: possible X-ray afterglow
  13. Identification of a possible optical counterpart for GRB990704
  14. GRB990704
  15. Refined BeppoSAX-WFC position of GRB990704
  16. GRB990704: BeppoSAX detection
  17. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  18. Optical Observations of GRB990627
  19. GRB 990627, radio observations
  20. GRB990627: BeppoSAX-WFC final location
  21. BeppoSAX: GRB990625
  22. Late-time HST/STIS Observation of GRB 990123
  23. GRB 990506 - clarification to GCN 352
  24. GRB 990506 - Optical Observations
  25. Optical Observations of GRB 990506
  26. GRB 990506 Radio Transient
  27. GRB990527 Optical Observations
  28. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  29. IPN error box for GRB990527
  30. Late Afterglows of GRBs 990510, 990123
  31. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  32. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  33. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  34. GRB 990506 optical observation
  35. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  36. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  37. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  38. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  39. radio observations of X-ray/GRB transient field
  40. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  41. Optical report on X-ray/GRB transient
  42. radio detection of X-ray/GRB transient
  43. BeppoSAX: A new fast X-ray transient
  44. GRB 990510: optical observations
  45. GRB990510: photometric and spectroscopic observations with the VLT
  46. GRB 990510: optical linear polarization
  47. GRB 990510: optical observations
  48. GRB990510, VI observations
  49. GRB 990506 R band observations
  50. GRB990510: X-ray afterglow
  51. GRB 990510: optical observation
  52. VLT spectrum of GRB990510
  53. GRB 990510: Broad Band Break
  54. GRB 990510: BATSE Observations
  55. GRB 990510 Optical Observations
  56. GRB 990510, BVI photometry
  57. GRB 990510 optical observations
  58. GRB 990510: BeppoSAX/GRBM observations
  59. GRB990510 optical observations
  60. GRB990510
  61. GRB 990510 optical observations
  62. GRB 990510 optical observations
  63. GRB990510: NFI X-ray source
  64. GRB 990510 optical observations
  65. IPN localization of GRB990510
  66. GRB 990506 Radio Observations
  67. GRB 990123, optical monitoring
  68. GRB 990506: BATSE Observations
  69. GRB 990506, optical observations
  70. GRB 990510: Final BeppoSAX-WFC Coordinates
  71. GRB 990506, Optical Observations
  72. GRB 990506, optical observations
  73. GRB990506 observation plan
  74. Refined IPN error box for GRB990506
  75. GRB 990506: Limits on the possible optical transient
  76. GRB 990506, armchair astronomy
  77. GRB 990506, optical observations from +1 to +3 hours
  78. GRB 990506, optical observations
  79. GRB990506 Optical observations
  80. GRB990506 observation plan
  81. New IPN/RXTE error box for GRB990506
  82. IPN localization for GRB990506
  83. GRB 970228: Redshift and properties of the host galaxy
  84. GRB981220 VLBA observations
  85. GRB980425 Optical observations of exponential decline at late time
  86. GRB990323 PRECISE IPN POSITION
  87. GRB990321 IPN TRIANGULATION
  88. GRB 990316 Optical Observations
  89. GRB 990316, Radio observations
  90. GRB 990316, Optical observations
  91. GRB990316, Optical observations
  92. GRB 990316 optical observations
  93. GRB990316: simultaneous optical observation
  94. GRB990316 - Optical null results
  95. ASM/IPN error box for GRB 990308 (BATSE #7457)
  96. GRB990308 not a new SGR
  97. GRB 990308a and GRB 990308b
  98. GRB990308 (Trig. 7457), optical observations
  99. GRB990308, Possible new SGR~0209+70
  100. GRB981220, IPN localization

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