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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"

21788 results found.

  1. GRB990806 UBVRIJHK observations
  2. GRB 990712 Optical Observations
  3. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  4. GRB 990712
  5. Late-time HST/STIS Observations of GRB 990510
  6. GRB 990705, R-band observations
  7. Infrared and Optical Observations of GRB990705
  8. GRB 990705, radio observations
  9. GRB990704 radio and optical observations
  10. GRB 990704 X-ray Observations
  11. GRB 990704 Optical Observations
  12. GRB 990704, optical observations
  13. GRB990705: Intriguing Positional Coincidences
  14. GRB990704
  15. GRB990704, optical observations
  16. Identification of a possible optical counterpart for GRB990704
  17. GRB990704
  18. Optical Observations of GRB990627
  19. GRB 990627, radio observations
  20. Late-time HST/STIS Observation of GRB 990123
  21. GRB 990506 - clarification to GCN 352
  22. GRB 990506 - Optical Observations
  23. Optical Observations of GRB 990506
  24. GRB990527 Optical Observations
  25. Late Afterglows of GRBs 990510, 990123
  26. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  27. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  28. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  29. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  30. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  31. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  32. radio observations of X-ray/GRB transient field
  33. Optical report on X-ray/GRB transient
  34. radio detection of X-ray/GRB transient
  35. BeppoSAX: A new fast X-ray transient
  36. GRB 990510: optical observations
  37. GRB990510: photometric and spectroscopic observations with the VLT
  38. GRB 990510: optical observations
  39. GRB990510, VI observations
  40. GRB 990506 R band observations
  41. GRB990510: X-ray afterglow
  42. GRB 990510: optical observation
  43. GRB 990510: Broad Band Break
  44. GRB 990510: BATSE Observations
  45. GRB 990510 Optical Observations
  46. GRB 990510, BVI photometry
  47. GRB 990510 optical observations
  48. GRB 990510: BeppoSAX/GRBM observations
  49. GRB990510 optical observations
  50. GRB990510
  51. GRB 990510 optical observations
  52. GRB 990510 optical observations
  53. GRB 990510 optical observations
  54. GRB 990506 Radio Observations
  55. GRB 990123, optical monitoring
  56. GRB 990506: BATSE Observations
  57. GRB 990506, optical observations
  58. GRB 990506, Optical Observations
  59. GRB 990506 optical observations
  60. GRB 990506 optical observations
  61. GRB 990506, optical observations
  62. GRB990506 observation plan
  63. GRB 990506: Limits on the possible optical transient
  64. GRB 990506, optical observations from +1 to +3 hours
  65. GRB 990506, optical observations
  66. GRB990506 Optical observations
  67. GRB 970228: Redshift and properties of the host galaxy
  68. GRB981220 VLBA observations
  69. GRB980425 Optical observations of exponential decline at late time
  70. GRB 990316 Optical Observations
  71. GRB 990316, Radio observations
  72. GRB 990316, Optical observations
  73. GRB990316, Optical observations
  74. GRB 990316 optical observations
  75. GRB990316: simultaneous optical observation
  76. GRB990308 not a new SGR
  77. GRB990308 (Trig. 7457), optical observations
  78. GRB990308, Possible new SGR~0209+70
  79. GRB 981220, radio observations
  80. GRB 990217 Optical Observations
  81. GRB 990217, radio observations
  82. Optical Observations of GRB990217
  83. GRB990123 observations
  84. GRB990123, Optical Observation
  85. GRB 990123: Discovery of the Probable Host Galaxy
  86. GRB 990123: Reduced HST Images
  87. For Immediate Posting to GCN - HST Data GRB 990123 Available
  88. GRB19990123 observations
  89. GRB 990123: Updated Keck Spectroscopy Results
  90. GRB981220, field photometry
  91. GRB 990123 NOT Spectrum Update
  92. GRB990123, Optical observation
  93. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  94. GRB 990123: Publicly available reduced HST images
  95. GRB990123, Upcoming HST Service Observations
  96. GRB990123, 15-GHz limits
  97. GRB 990123: New Constraints on Possible Foreground Galaxies
  98. GRB990123 Optical Observations
  99. GRB990123, Probability of gravitational lensing
  100. GRB 990123: Detection of the IR Transient, and the Light Curve Fits

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