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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. BeppoSAX NFI Observation of GRB990705
  2. Updated Astrometry for the IR Counterpart of GRB990705
  3. GRB 990705, R-band observations
  4. Updated IPN localization of GRB990705
  5. IPN localization of GRB990704
  6. IPN localization of GRB990705
  7. Infrared and Optical Observations of GRB990705
  8. GRB 990705, radio observations
  9. GRB990704: SAX-NFI results summary
  10. GRB990704 radio and optical observations
  11. BeppoSAX GRB990705: possible X-ray afterglow
  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. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  19. GRB990704, optical observations
  20. GRB990704: possible X-ray afterglow
  21. Identification of a possible optical counterpart for GRB990704
  22. GRB990704
  23. Refined BeppoSAX-WFC position of GRB990704
  24. GRB990704: BeppoSAX detection
  25. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  26. Optical Observations of GRB990627
  27. GRB 990627, radio observations
  28. GRB990627: BeppoSAX-WFC final location
  29. BeppoSAX: GRB990625
  30. Late-time HST/STIS Observation of GRB 990123
  31. GRB 990506 - clarification to GCN 352
  32. GRB 990506 - Optical Observations
  33. Optical Observations of GRB 990506
  34. GRB 990506 Radio Transient
  35. GRB990527 Optical Observations
  36. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  37. IPN error box for GRB990527
  38. Late Afterglows of GRBs 990510, 990123
  39. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  40. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  41. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  42. GRB 990506 optical observation
  43. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  44. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  45. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  46. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  47. radio observations of X-ray/GRB transient field
  48. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  49. Optical report on X-ray/GRB transient
  50. radio detection of X-ray/GRB transient
  51. BeppoSAX: A new fast X-ray transient
  52. GRB 990510: optical observations
  53. GRB990510: photometric and spectroscopic observations with the VLT
  54. GRB 990510: optical linear polarization
  55. GRB 990510: optical observations
  56. GRB990510, VI observations
  57. GRB 990506 R band observations
  58. GRB990510: X-ray afterglow
  59. GRB 990510: optical observation
  60. VLT spectrum of GRB990510
  61. GRB 990510: Broad Band Break
  62. GRB 990510: BATSE Observations
  63. GRB990510: optical observation
  64. GRB 990510 Optical Observations
  65. GRB 990510, BVI photometry
  66. GRB 990510 optical observations
  67. GRB 990510: BeppoSAX/GRBM observations
  68. GRB990510 optical observations
  69. GRB990510
  70. GRB 990510 optical observations
  71. GRB 990510 optical observations
  72. Galactic extinction towards GRB 990510
  73. GRB990510: NFI X-ray source
  74. GRB 990510 optical observations
  75. IPN localization of GRB990510
  76. GRB 990506 Radio Observations
  77. GRB 990123, optical monitoring
  78. GRB 990506: BATSE Observations
  79. GRB 990506, optical observations
  80. GRB 990510: Final BeppoSAX-WFC Coordinates
  81. GRB 990506, Optical Observations
  82. GRB 990506 optical observations
  83. GRB 990506 optical observations
  84. GRB 990506, optical observations
  85. GRB990506 observation plan
  86. Refined IPN error box for GRB990506
  87. GRB 990506: Limits on the possible optical transient
  88. GRB 990506, armchair astronomy
  89. GRB 990506, optical observations from +1 to +3 hours
  90. GRB 990506, optical observations
  91. GRB990506 Optical observations
  92. GRB990506 observation plan
  93. New IPN/RXTE error box for GRB990506
  94. IPN localization for GRB990506
  95. GRB 970228: Redshift and properties of the host galaxy
  96. IPN localization of GRB990427
  97. GRB981220 VLBA observations
  98. GRB980425 Optical observations of exponential decline at late time
  99. GRB990321 REFINED IPN ANNULUS
  100. GRB990323 PRECISE IPN POSITION

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