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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"

42181 results found.

  1. GRB 990712, Optical Observation
  2. GRB990806 BeppoSAX follow up
  3. GRB990806: BATSE Observations
  4. GRB 990806 Optical observations
  5. Optical Observations of GRB990806
  6. GRB 990806, Optical Observations
  7. GRB 990806, optical observations
  8. GRB 990806, Optical Observations
  9. GRB990806 UBVRIJHK observations
  10. GRB990806: possible X-ray afterglow, BeppoSAX
  11. BeppoSAX ALERT GRB990806: Summer GRB
  12. GRB 990712 Optical Observations
  13. GRB990705: No Evidence for Neutrino Signal
  14. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  15. VLT spectrum of GRB990712
  16. GRB 990712
  17. Late-time HST/STIS Observations of GRB 990510
  18. Refined BeppoSAX-WFC position of GRB990712
  19. GRB 990705, R-band observations
  20. Updated IPN localization of GRB990705
  21. IPN localization of GRB990704
  22. Infrared and Optical Observations of GRB990705
  23. GRB 990705, radio observations
  24. GRB990704 radio and optical observations
  25. GRB 990704 X-ray Observations
  26. GRB 990704 Optical Observations
  27. GRB 990704, optical observations
  28. GRB990704
  29. GRB990705: Intriguing Positional Coincidences
  30. GRB990704
  31. GRB990704, optical observations
  32. Identification of a possible optical counterpart for GRB990704
  33. GRB990704
  34. Refined BeppoSAX-WFC position of GRB990704
  35. GRB990704: BeppoSAX detection
  36. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  37. Optical Observations of GRB990627
  38. GRB 990627, radio observations
  39. BeppoSAX: GRB990625
  40. Late-time HST/STIS Observation of GRB 990123
  41. GRB 990506 - clarification to GCN 352
  42. GRB 990506 - Optical Observations
  43. Optical Observations of GRB 990506
  44. GRB 990506 Radio Transient
  45. GRB990527 Optical Observations
  46. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  47. IPN error box for GRB990527
  48. Late Afterglows of GRBs 990510, 990123
  49. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  50. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  51. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  52. GRB 990506 optical observation
  53. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  54. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  55. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  56. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  57. radio observations of X-ray/GRB transient field
  58. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  59. Optical report on X-ray/GRB transient
  60. BeppoSAX: A new fast X-ray transient
  61. GRB 990510: optical observations
  62. GRB990510: photometric and spectroscopic observations with the VLT
  63. GRB 990510: optical linear polarization
  64. GRB 990510: optical observations
  65. GRB990510, VI observations
  66. GRB 990506 R band observations
  67. GRB990510: X-ray afterglow
  68. GRB 990510: optical observation
  69. VLT spectrum of GRB990510
  70. GRB 990510: Broad Band Break
  71. GRB 990510: BATSE Observations
  72. GRB990510: optical observation
  73. GRB 990510 Optical Observations
  74. GRB 990510, BVI photometry
  75. GRB 990510 optical observations
  76. GRB 990510: BeppoSAX/GRBM observations
  77. GRB990510 optical observations
  78. GRB990510
  79. GRB 990510 optical observations
  80. GRB 990510 optical observations
  81. Galactic extinction towards GRB 990510
  82. GRB 990510 optical observations
  83. IPN localization of GRB990510
  84. GRB 990123, optical monitoring
  85. GRB 990506: BATSE Observations
  86. GRB 990506, optical observations
  87. GRB 990510: Final BeppoSAX-WFC Coordinates
  88. GRB 990506, Optical Observations
  89. GRB 990506 optical observations
  90. GRB 990506 optical observations
  91. GRB 990506, optical observations
  92. GRB990506 observation plan
  93. Refined IPN error box for GRB990506
  94. GRB 990506: Limits on the possible optical transient
  95. GRB 990506, armchair astronomy
  96. GRB 990506, optical observations from +1 to +3 hours
  97. GRB 990506, optical observations
  98. GRB990506 Optical observations
  99. GRB990506 observation plan
  100. New IPN/RXTE error box for GRB990506

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