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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. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  2. IPN error box for GRB990527
  3. Late Afterglows of GRBs 990510, 990123
  4. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  5. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  6. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  7. GRB 990506 optical observation
  8. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  9. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  10. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  11. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  12. radio observations of X-ray/GRB transient field
  13. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  14. Optical report on X-ray/GRB transient
  15. radio detection of X-ray/GRB transient
  16. BeppoSAX: A new fast X-ray transient
  17. GRB 990510: optical observations
  18. GRB990510: photometric and spectroscopic observations with the VLT
  19. GRB 990510: optical linear polarization
  20. GRB 990510: optical observations
  21. GRB990510, VI observations
  22. GRB 990506 R band observations
  23. GRB990510: X-ray afterglow
  24. GRB 990510: optical observation
  25. VLT spectrum of GRB990510
  26. GRB 990510: Broad Band Break
  27. GRB 990510: BATSE Observations
  28. GRB990510: optical observation
  29. GRB 990510 Optical Observations
  30. GRB 990510, BVI photometry
  31. GRB 990510 optical observations
  32. GRB 990510: BeppoSAX/GRBM observations
  33. GRB990510 optical observations
  34. GRB990510
  35. GRB 990510 optical observations
  36. GRB 990510 optical observations
  37. Galactic extinction towards GRB 990510
  38. GRB990510: NFI X-ray source
  39. GRB 990510 optical observations
  40. IPN localization of GRB990510
  41. GRB 990506 Radio Observations
  42. GRB 990123, optical monitoring
  43. GRB 990506: BATSE Observations
  44. GRB 990506, optical observations
  45. GRB 990510: Final BeppoSAX-WFC Coordinates
  46. GRB 990506, Optical Observations
  47. GRB 990506 optical observations
  48. GRB 990506 optical observations
  49. GRB 990506, optical observations
  50. GRB990506 observation plan
  51. Refined IPN error box for GRB990506
  52. GRB 990506: Limits on the possible optical transient
  53. GRB 990506, armchair astronomy
  54. GRB 990506, optical observations from +1 to +3 hours
  55. GRB 990506, optical observations
  56. GRB990506 Optical observations
  57. GRB990506 observation plan
  58. New IPN/RXTE error box for GRB990506
  59. IPN localization for GRB990506
  60. GRB 970228: Redshift and properties of the host galaxy
  61. IPN localization of GRB990427
  62. GRB981220 VLBA observations
  63. GRB980425 Optical observations of exponential decline at late time
  64. GRB990321 REFINED IPN ANNULUS
  65. GRB990323 PRECISE IPN POSITION
  66. GRB990321 IPN TRIANGULATION
  67. GRB 990316 Optical Observations
  68. GRB 990316, Radio observations
  69. GRB 990316, Optical observations
  70. GRB990316, Optical observations
  71. GRB 990316 optical observations
  72. GRB990316: simultaneous optical observation
  73. GRB990316 - Optical null results
  74. ASM/IPN error box for GRB 990308 (BATSE #7457)
  75. GRB990308 not a new SGR
  76. GRB 990308a and GRB 990308b
  77. GRB990308 (Trig. 7457), optical observations
  78. GRB990308, Possible new SGR~0209+70
  79. GRB981220, IPN localization
  80. GRB 981220, radio observations
  81. GRB 990123, Field Photometry
  82. GRB 990217 Optical Observations
  83. GRB 990217, radio observations
  84. BATSE Resumes Normal Operations
  85. BATSE Flight Anomaly
  86. GRB990217: BeppoSAX/GRBM data
  87. Optical Observations of GRB990217
  88. GRB990123: Caltech STIS Photometry and Images
  89. GRB990123 observations
  90. GRB990217 Optical observation
  91. GRB990217, WFC position
  92. GRB990123, Optical Observation
  93. GRB 990123: Discovery of the Probable Host Galaxy
  94. GRB 990123: Reduced HST Images
  95. For Immediate Posting to GCN - HST Data GRB 990123 Available
  96. GRB19990123 observations
  97. GRB 990123: BVRI standards in the field
  98. GRB 990123: Updated Keck Spectroscopy Results
  99. GRB981220, field photometry
  100. GRB 990123 NOT Spectrum Update

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