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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').
  1. GRB 990806 Optical observations
  2. Optical Observations of GRB990806
  3. GRB 990806, Optical Observations
  4. GRB 990806, optical observations
  5. GRB 990806, Optical Observations
  6. GRB990806 UBVRIJHK observations
  7. GRB990806: possible X-ray afterglow, BeppoSAX
  8. BeppoSAX ALERT GRB990806: Summer GRB
  9. GRB 990712 Optical Observations
  10. GRB990705: No Evidence for Neutrino Signal
  11. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  12. VLT spectrum of GRB990712
  13. GRB 990712
  14. Late-time HST/STIS Observations of GRB 990510
  15. Refined BeppoSAX-WFC position of GRB990712
  16. BeppoSAX NFI Observation of GRB990705
  17. BeppoSAX NFI Observation of GRB990705
  18. Updated Astrometry for the IR Counterpart of GRB990705
  19. GRB 990705, R-band observations
  20. Updated IPN localization of GRB990705
  21. IPN localization of GRB990704
  22. IPN localization of GRB990705
  23. Infrared and Optical Observations of GRB990705
  24. GRB 990705, radio observations
  25. GRB990704: SAX-NFI results summary
  26. GRB990704 radio and optical observations
  27. BeppoSAX GRB990705: possible X-ray afterglow
  28. GRB 990704 X-ray Observations
  29. GRB 990704 Optical Observations
  30. GRB 990704, optical observations
  31. GRB990704
  32. GRB990705: Intriguing Positional Coincidences
  33. GRB990704
  34. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  35. GRB990704, optical observations
  36. GRB990704: possible X-ray afterglow
  37. Identification of a possible optical counterpart for GRB990704
  38. GRB990704
  39. Refined BeppoSAX-WFC position of GRB990704
  40. GRB990704: BeppoSAX detection
  41. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  42. Optical Observations of GRB990627
  43. GRB 990627, radio observations
  44. GRB990627: BeppoSAX-WFC final location
  45. BeppoSAX: GRB990625
  46. Late-time HST/STIS Observation of GRB 990123
  47. GRB 990506 - clarification to GCN 352
  48. GRB 990506 - Optical Observations
  49. Optical Observations of GRB 990506
  50. GRB 990506 Radio Transient
  51. GRB990527 Optical Observations
  52. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  53. IPN error box for GRB990527
  54. Late Afterglows of GRBs 990510, 990123
  55. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  56. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  57. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  58. GRB 990506 optical observation
  59. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  60. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  61. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  62. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  63. radio observations of X-ray/GRB transient field
  64. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  65. Optical report on X-ray/GRB transient
  66. radio detection of X-ray/GRB transient
  67. BeppoSAX: A new fast X-ray transient
  68. GRB 990510: optical observations
  69. GRB990510: photometric and spectroscopic observations with the VLT
  70. GRB 990510: optical linear polarization
  71. GRB 990510: optical observations
  72. GRB990510, VI observations
  73. GRB 990506 R band observations
  74. GRB990510: X-ray afterglow
  75. GRB 990510: optical observation
  76. VLT spectrum of GRB990510
  77. GRB 990510: Broad Band Break
  78. GRB 990510: BATSE Observations
  79. GRB990510: optical observation
  80. GRB 990510 Optical Observations
  81. GRB 990510, BVI photometry
  82. GRB 990510 optical observations
  83. GRB 990510: BeppoSAX/GRBM observations
  84. GRB990510 optical observations
  85. GRB990510
  86. GRB 990510 optical observations
  87. GRB 990510 optical observations
  88. Galactic extinction towards GRB 990510
  89. GRB990510: NFI X-ray source
  90. GRB 990510 optical observations
  91. IPN localization of GRB990510
  92. GRB 990506 Radio Observations
  93. GRB 990123, optical monitoring
  94. GRB 990506: BATSE Observations
  95. GRB 990506, optical observations
  96. GRB 990510: Final BeppoSAX-WFC Coordinates
  97. GRB 990506, Optical Observations
  98. GRB 990506 optical observations
  99. GRB 990506 optical observations
  100. GRB 990506, optical observations

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