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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"

21793 results found.

  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. GRB 990712 Optical Observations
  8. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  9. GRB 990712
  10. Late-time HST/STIS Observations of GRB 990510
  11. GRB 990705, R-band observations
  12. Infrared and Optical Observations of GRB990705
  13. GRB 990705, radio observations
  14. GRB990704 radio and optical observations
  15. GRB 990704 X-ray Observations
  16. GRB 990704 Optical Observations
  17. GRB 990704, optical observations
  18. GRB990705: Intriguing Positional Coincidences
  19. GRB990704
  20. GRB990704, optical observations
  21. Identification of a possible optical counterpart for GRB990704
  22. GRB990704
  23. Optical Observations of GRB990627
  24. GRB 990627, radio observations
  25. Late-time HST/STIS Observation of GRB 990123
  26. GRB 990506 - clarification to GCN 352
  27. GRB 990506 - Optical Observations
  28. Optical Observations of GRB 990506
  29. GRB990527 Optical Observations
  30. Late Afterglows of GRBs 990510, 990123
  31. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  32. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  33. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  34. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  35. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  36. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  37. radio observations of X-ray/GRB transient field
  38. Optical report on X-ray/GRB transient
  39. radio detection of X-ray/GRB transient
  40. BeppoSAX: A new fast X-ray transient
  41. GRB 990510: optical observations
  42. GRB990510: photometric and spectroscopic observations with the VLT
  43. GRB 990510: optical observations
  44. GRB990510, VI observations
  45. GRB 990506 R band observations
  46. GRB990510: X-ray afterglow
  47. GRB 990510: optical observation
  48. GRB 990510: Broad Band Break
  49. GRB 990510: BATSE Observations
  50. GRB 990510 Optical Observations
  51. GRB 990510, BVI photometry
  52. GRB 990510 optical observations
  53. GRB 990510: BeppoSAX/GRBM observations
  54. GRB990510 optical observations
  55. GRB990510
  56. GRB 990510 optical observations
  57. GRB 990510 optical observations
  58. GRB 990510 optical observations
  59. GRB 990506 Radio Observations
  60. GRB 990123, optical monitoring
  61. GRB 990506: BATSE Observations
  62. GRB 990506, optical observations
  63. GRB 990506, Optical Observations
  64. GRB 990506 optical observations
  65. GRB 990506 optical observations
  66. GRB 990506, optical observations
  67. GRB990506 observation plan
  68. GRB 990506: Limits on the possible optical transient
  69. GRB 990506, optical observations from +1 to +3 hours
  70. GRB 990506, optical observations
  71. GRB990506 Optical observations
  72. GRB 970228: Redshift and properties of the host galaxy
  73. GRB981220 VLBA observations
  74. GRB980425 Optical observations of exponential decline at late time
  75. GRB 990316 Optical Observations
  76. GRB 990316, Radio observations
  77. GRB 990316, Optical observations
  78. GRB990316, Optical observations
  79. GRB 990316 optical observations
  80. GRB990316: simultaneous optical observation
  81. GRB990308 not a new SGR
  82. GRB990308 (Trig. 7457), optical observations
  83. GRB990308, Possible new SGR~0209+70
  84. GRB 981220, radio observations
  85. GRB 990217 Optical Observations
  86. GRB 990217, radio observations
  87. Optical Observations of GRB990217
  88. GRB990123 observations
  89. GRB990123, Optical Observation
  90. GRB 990123: Discovery of the Probable Host Galaxy
  91. GRB 990123: Reduced HST Images
  92. For Immediate Posting to GCN - HST Data GRB 990123 Available
  93. GRB19990123 observations
  94. GRB 990123: Updated Keck Spectroscopy Results
  95. GRB981220, field photometry
  96. GRB 990123 NOT Spectrum Update
  97. GRB990123, Optical observation
  98. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  99. GRB 990123: Publicly available reduced HST images
  100. GRB990123, Upcoming HST Service Observations

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