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

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