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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. Late-time HST/STIS Observations of GRB 990510
  2. Refined BeppoSAX-WFC position of GRB990712
  3. BeppoSAX NFI Observation of GRB990705
  4. BeppoSAX NFI Observation of GRB990705
  5. Updated Astrometry for the IR Counterpart of GRB990705
  6. GRB 990705, R-band observations
  7. Updated IPN localization of GRB990705
  8. IPN localization of GRB990704
  9. IPN localization of GRB990705
  10. Infrared and Optical Observations of GRB990705
  11. GRB 990705, radio observations
  12. GRB990704: SAX-NFI results summary
  13. GRB990704 radio and optical observations
  14. BeppoSAX GRB990705: possible X-ray afterglow
  15. GRB 990704 X-ray Observations
  16. GRB 990704 Optical Observations
  17. GRB 990704, optical observations
  18. GRB990704
  19. GRB990705: Intriguing Positional Coincidences
  20. GRB990704
  21. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  22. GRB990704, optical observations
  23. GRB990704: possible X-ray afterglow
  24. Identification of a possible optical counterpart for GRB990704
  25. GRB990704
  26. Refined BeppoSAX-WFC position of GRB990704
  27. GRB990704: BeppoSAX detection
  28. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  29. Optical Observations of GRB990627
  30. GRB 990627, radio observations
  31. GRB990627: BeppoSAX-WFC final location
  32. BeppoSAX: GRB990625
  33. Late-time HST/STIS Observation of GRB 990123
  34. GRB 990506 - clarification to GCN 352
  35. GRB 990506 - Optical Observations
  36. Optical Observations of GRB 990506
  37. GRB 990506 Radio Transient
  38. GRB990527 Optical Observations
  39. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  40. IPN error box for GRB990527
  41. Late Afterglows of GRBs 990510, 990123
  42. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  43. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  44. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  45. GRB 990506 optical observation
  46. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  47. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  48. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  49. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  50. radio observations of X-ray/GRB transient field
  51. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  52. Optical report on X-ray/GRB transient
  53. radio detection of X-ray/GRB transient
  54. BeppoSAX: A new fast X-ray transient
  55. GRB 990510: optical observations
  56. GRB990510: photometric and spectroscopic observations with the VLT
  57. GRB 990510: optical linear polarization
  58. GRB 990510: optical observations
  59. GRB990510, VI observations
  60. GRB 990506 R band observations
  61. GRB990510: X-ray afterglow
  62. GRB 990510: optical observation
  63. VLT spectrum of GRB990510
  64. GRB 990510: Broad Band Break
  65. GRB 990510: BATSE Observations
  66. GRB990510: optical observation
  67. GRB 990510 Optical Observations
  68. GRB 990510, BVI photometry
  69. GRB 990510 optical observations
  70. GRB 990510: BeppoSAX/GRBM observations
  71. GRB990510 optical observations
  72. GRB990510
  73. GRB 990510 optical observations
  74. GRB 990510 optical observations
  75. Galactic extinction towards GRB 990510
  76. GRB990510: NFI X-ray source
  77. GRB 990510 optical observations
  78. IPN localization of GRB990510
  79. GRB 990506 Radio Observations
  80. GRB 990123, optical monitoring
  81. GRB 990506: BATSE Observations
  82. GRB 990506, optical observations
  83. GRB 990510: Final BeppoSAX-WFC Coordinates
  84. GRB 990506, Optical Observations
  85. GRB 990506 optical observations
  86. GRB 990506 optical observations
  87. GRB 990506, optical observations
  88. GRB990506 observation plan
  89. Refined IPN error box for GRB990506
  90. GRB 990506: Limits on the possible optical transient
  91. GRB 990506, armchair astronomy
  92. GRB 990506, optical observations from +1 to +3 hours
  93. GRB 990506, optical observations
  94. GRB990506 Optical observations
  95. GRB990506 observation plan
  96. New IPN/RXTE error box for GRB990506
  97. IPN localization for GRB990506
  98. GRB 970228: Redshift and properties of the host galaxy
  99. IPN localization of GRB990427
  100. GRB981220 VLBA observations

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