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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"

35422 results found.

  1. VLT spectrum of GRB990712
  2. GRB 990712
  3. Late-time HST/STIS Observations of GRB 990510
  4. Refined BeppoSAX-WFC position of GRB990712
  5. GRB 990705, R-band observations
  6. Updated IPN localization of GRB990705
  7. IPN localization of GRB990704
  8. IPN localization of GRB990705
  9. Infrared and Optical Observations of GRB990705
  10. GRB 990705, radio observations
  11. GRB990704 radio and optical observations
  12. GRB 990704 X-ray Observations
  13. GRB 990704 Optical Observations
  14. GRB 990704, optical observations
  15. GRB990704
  16. GRB990705: Intriguing Positional Coincidences
  17. GRB990704
  18. GRB990704, optical observations
  19. Identification of a possible optical counterpart for GRB990704
  20. GRB990704
  21. Refined BeppoSAX-WFC position of GRB990704
  22. GRB990704: BeppoSAX detection
  23. Optical Observations of GRB990627
  24. GRB 990627, radio observations
  25. GRB990627: BeppoSAX-WFC final location
  26. BeppoSAX: GRB990625
  27. Late-time HST/STIS Observation of GRB 990123
  28. GRB 990506 - clarification to GCN 352
  29. GRB 990506 - Optical Observations
  30. Optical Observations of GRB 990506
  31. GRB 990506 Radio Transient
  32. GRB990527 Optical Observations
  33. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  34. IPN error box for GRB990527
  35. Late Afterglows of GRBs 990510, 990123
  36. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  37. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  38. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  39. GRB 990506 optical observation
  40. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  41. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  42. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  43. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  44. radio observations of X-ray/GRB transient field
  45. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  46. Optical report on X-ray/GRB transient
  47. radio detection of X-ray/GRB transient
  48. BeppoSAX: A new fast X-ray transient
  49. GRB 990510: optical observations
  50. GRB990510: photometric and spectroscopic observations with the VLT
  51. GRB 990510: optical linear polarization
  52. GRB 990510: optical observations
  53. GRB990510, VI observations
  54. GRB 990506 R band observations
  55. GRB990510: X-ray afterglow
  56. GRB 990510: optical observation
  57. VLT spectrum of GRB990510
  58. GRB 990510: Broad Band Break
  59. GRB 990510: BATSE Observations
  60. GRB 990510 Optical Observations
  61. GRB 990510, BVI photometry
  62. GRB 990510 optical observations
  63. GRB 990510: BeppoSAX/GRBM observations
  64. GRB990510 optical observations
  65. GRB 990510 optical observations
  66. GRB 990510 optical observations
  67. Galactic extinction towards GRB 990510
  68. GRB 990510 optical observations
  69. IPN localization of GRB990510
  70. GRB 990506 Radio Observations
  71. GRB 990123, optical monitoring
  72. GRB 990506: BATSE Observations
  73. GRB 990506, optical observations
  74. GRB 990510: Final BeppoSAX-WFC Coordinates
  75. GRB 990506, Optical Observations
  76. GRB 990506 optical observations
  77. GRB 990506 optical observations
  78. GRB 990506, optical observations
  79. GRB990506 observation plan
  80. Refined IPN error box for GRB990506
  81. GRB 990506: Limits on the possible optical transient
  82. GRB 990506, armchair astronomy
  83. GRB 990506, optical observations from +1 to +3 hours
  84. GRB 990506, optical observations
  85. GRB990506 observation plan
  86. New IPN/RXTE error box for GRB990506
  87. IPN localization for GRB990506
  88. GRB 970228: Redshift and properties of the host galaxy
  89. IPN localization of GRB990427
  90. GRB981220 VLBA observations
  91. GRB990321 REFINED IPN ANNULUS
  92. GRB990323 PRECISE IPN POSITION
  93. GRB990321 IPN TRIANGULATION
  94. GRB 990316 Optical Observations
  95. GRB 990316, Radio observations
  96. GRB 990316, Optical observations
  97. GRB990316, Optical observations
  98. GRB 990316 optical observations
  99. GRB990316: simultaneous optical observation
  100. ASM/IPN error box for GRB 990308 (BATSE #7457)

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