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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"

42744 results found.

  1. GRB 990506 - clarification to GCN 352
  2. GRB 990506 - Optical Observations
  3. Optical Observations of GRB 990506
  4. GRB 990506 Radio Transient
  5. GRB990527 Optical Observations
  6. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  7. IPN error box for GRB990527
  8. Late Afterglows of GRBs 990510, 990123
  9. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  10. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  11. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  12. GRB 990506 optical observation
  13. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  14. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  15. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  16. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  17. radio observations of X-ray/GRB transient field
  18. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  19. Optical report on X-ray/GRB transient
  20. radio detection of X-ray/GRB transient
  21. BeppoSAX: A new fast X-ray transient
  22. GRB 990510: optical observations
  23. GRB990510: photometric and spectroscopic observations with the VLT
  24. GRB 990510: optical observations
  25. GRB990510, VI observations
  26. GRB 990506 R band observations
  27. GRB990510: X-ray afterglow
  28. GRB 990510: optical observation
  29. VLT spectrum of GRB990510
  30. GRB 990510: Broad Band Break
  31. GRB 990510: BATSE Observations
  32. GRB 990510 Optical Observations
  33. GRB 990510, BVI photometry
  34. GRB 990510 optical observations
  35. GRB 990510: BeppoSAX/GRBM observations
  36. GRB990510 optical observations
  37. GRB990510
  38. GRB 990510 optical observations
  39. GRB 990510 optical observations
  40. Galactic extinction towards GRB 990510
  41. GRB 990510 optical observations
  42. IPN localization of GRB990510
  43. GRB 990506 Radio Observations
  44. GRB 990123, optical monitoring
  45. GRB 990506: BATSE Observations
  46. GRB 990506, optical observations
  47. GRB 990510: Final BeppoSAX-WFC Coordinates
  48. GRB 990506, Optical Observations
  49. GRB 990506 optical observations
  50. GRB 990506 optical observations
  51. GRB 990506, optical observations
  52. GRB990506 observation plan
  53. Refined IPN error box for GRB990506
  54. GRB 990506: Limits on the possible optical transient
  55. GRB 990506, optical observations from +1 to +3 hours
  56. GRB 990506, optical observations
  57. GRB990506 Optical observations
  58. GRB990506 observation plan
  59. New IPN/RXTE error box for GRB990506
  60. IPN localization for GRB990506
  61. GRB 970228: Redshift and properties of the host galaxy
  62. IPN localization of GRB990427
  63. GRB981220 VLBA observations
  64. GRB980425 Optical observations of exponential decline at late time
  65. GRB990321 REFINED IPN ANNULUS
  66. GRB990323 PRECISE IPN POSITION
  67. GRB990321 IPN TRIANGULATION
  68. GRB 990316 Optical Observations
  69. GRB 990316, Radio observations
  70. GRB 990316, Optical observations
  71. GRB990316, Optical observations
  72. GRB 990316 optical observations
  73. GRB990316: simultaneous optical observation
  74. GRB990316 - Optical null results
  75. ASM/IPN error box for GRB 990308 (BATSE #7457)
  76. GRB990308 not a new SGR
  77. GRB 990308a and GRB 990308b
  78. GRB990308 (Trig. 7457), optical observations
  79. GRB990308, Possible new SGR~0209+70
  80. GRB981220, IPN localization
  81. GRB 981220, radio observations
  82. GRB 990123, Field Photometry
  83. GRB 990217 Optical Observations
  84. GRB 990217, radio observations
  85. BATSE Resumes Normal Operations
  86. BATSE Flight Anomaly
  87. GRB990217: BeppoSAX/GRBM data
  88. Optical Observations of GRB990217
  89. GRB990123: Caltech STIS Photometry and Images
  90. GRB990123 observations
  91. GRB990217 Optical observation
  92. GRB 990123: Discovery of the Probable Host Galaxy
  93. GRB 990123: Reduced HST Images
  94. For Immediate Posting to GCN - HST Data GRB 990123 Available
  95. GRB19990123 observations
  96. GRB 990123: BVRI standards in the field
  97. GRB 990123: Updated Keck Spectroscopy Results
  98. GRB981220, field photometry
  99. GRB 990123 NOT Spectrum Update
  100. GRB990123, Optical observation

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