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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"

37203 results found.

  1. Identification of a possible optical counterpart for GRB990704
  2. GRB990704
  3. Refined BeppoSAX-WFC position of GRB990704
  4. GRB990704: BeppoSAX detection
  5. Optical Observations of GRB990627
  6. GRB 990627, radio observations
  7. GRB990627: BeppoSAX-WFC final location
  8. BeppoSAX: GRB990625
  9. Late-time HST/STIS Observation of GRB 990123
  10. GRB 990506 - clarification to GCN 352
  11. GRB 990506 - Optical Observations
  12. Optical Observations of GRB 990506
  13. GRB 990506 Radio Transient
  14. GRB990527 Optical Observations
  15. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  16. IPN error box for GRB990527
  17. Late Afterglows of GRBs 990510, 990123
  18. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  19. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  20. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  21. GRB 990506 optical observation
  22. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  23. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  24. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  25. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  26. radio observations of X-ray/GRB transient field
  27. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  28. Optical report on X-ray/GRB transient
  29. radio detection of X-ray/GRB transient
  30. BeppoSAX: A new fast X-ray transient
  31. GRB 990510: optical observations
  32. GRB990510: photometric and spectroscopic observations with the VLT
  33. GRB 990510: optical linear polarization
  34. GRB 990510: optical observations
  35. GRB990510, VI observations
  36. GRB 990506 R band observations
  37. GRB990510: X-ray afterglow
  38. GRB 990510: optical observation
  39. VLT spectrum of GRB990510
  40. GRB 990510: Broad Band Break
  41. GRB 990510: BATSE Observations
  42. GRB 990510 Optical Observations
  43. GRB 990510, BVI photometry
  44. GRB 990510 optical observations
  45. GRB 990510: BeppoSAX/GRBM observations
  46. GRB990510 optical observations
  47. GRB 990510 optical observations
  48. GRB 990510 optical observations
  49. Galactic extinction towards GRB 990510
  50. GRB 990510 optical observations
  51. IPN localization of GRB990510
  52. GRB 990506 Radio Observations
  53. GRB 990123, optical monitoring
  54. GRB 990506: BATSE Observations
  55. GRB 990506, optical observations
  56. GRB 990510: Final BeppoSAX-WFC Coordinates
  57. GRB 990506, Optical Observations
  58. GRB 990506 optical observations
  59. GRB 990506 optical observations
  60. GRB 990506, optical observations
  61. GRB990506 observation plan
  62. Refined IPN error box for GRB990506
  63. GRB 990506: Limits on the possible optical transient
  64. GRB 990506, armchair astronomy
  65. GRB 990506, optical observations from +1 to +3 hours
  66. GRB 990506, optical observations
  67. GRB990506 observation plan
  68. New IPN/RXTE error box for GRB990506
  69. IPN localization for GRB990506
  70. GRB 970228: Redshift and properties of the host galaxy
  71. IPN localization of GRB990427
  72. GRB981220 VLBA observations
  73. GRB990321 REFINED IPN ANNULUS
  74. GRB990323 PRECISE IPN POSITION
  75. GRB990321 IPN TRIANGULATION
  76. GRB 990316 Optical Observations
  77. GRB 990316, Radio observations
  78. GRB 990316, Optical observations
  79. GRB990316, Optical observations
  80. GRB 990316 optical observations
  81. GRB990316: simultaneous optical observation
  82. ASM/IPN error box for GRB 990308 (BATSE #7457)
  83. GRB990308 not a new SGR
  84. GRB 990308a and GRB 990308b
  85. GRB990308 (Trig. 7457), optical observations
  86. GRB981220, IPN localization
  87. GRB 981220, radio observations
  88. GRB 990123, Field Photometry
  89. GRB 990217 Optical Observations
  90. GRB 990217, radio observations
  91. Optical Observations of GRB990217
  92. GRB990123: Caltech STIS Photometry and Images
  93. GRB990123 observations
  94. GRB990123, Optical Observation
  95. GRB 990123: Discovery of the Probable Host Galaxy
  96. GRB 990123: Reduced HST Images
  97. For Immediate Posting to GCN - HST Data GRB 990123 Available
  98. GRB19990123 observations
  99. GRB 990123: BVRI standards in the field
  100. GRB 990123: Updated Keck Spectroscopy Results

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