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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"

21575 results found.

  1. GRB 990705, radio observations
  2. GRB990704 radio and optical observations
  3. BeppoSAX GRB990705: possible X-ray afterglow
  4. GRB 990704 X-ray Observations
  5. GRB 990704 Optical Observations
  6. GRB 990704, optical observations
  7. GRB990705: Intriguing Positional Coincidences
  8. GRB990704
  9. GRB990704, optical observations
  10. Identification of a possible optical counterpart for GRB990704
  11. GRB990704
  12. Optical Observations of GRB990627
  13. GRB 990627, radio observations
  14. Late-time HST/STIS Observation of GRB 990123
  15. GRB 990506 - Optical Observations
  16. Optical Observations of GRB 990506
  17. GRB990527 Optical Observations
  18. IPN error box for GRB990527
  19. Late Afterglows of GRBs 990510, 990123
  20. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  21. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  22. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  23. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  24. radio observations of X-ray/GRB transient field
  25. Optical report on X-ray/GRB transient
  26. radio detection of X-ray/GRB transient
  27. BeppoSAX: A new fast X-ray transient
  28. GRB 990510: optical observations
  29. GRB990510: photometric and spectroscopic observations with the VLT
  30. GRB 990510: optical observations
  31. GRB990510, VI observations
  32. GRB 990506 R band observations
  33. GRB990510: X-ray afterglow
  34. GRB 990510: Broad Band Break
  35. GRB 990510: BATSE Observations
  36. GRB 990510 Optical Observations
  37. GRB 990510, BVI photometry
  38. GRB 990510 optical observations
  39. GRB 990510: BeppoSAX/GRBM observations
  40. GRB990510 optical observations
  41. GRB990510
  42. GRB 990510 optical observations
  43. GRB 990510 optical observations
  44. GRB 990510 optical observations
  45. GRB 990506 Radio Observations
  46. GRB 990123, optical monitoring
  47. GRB 990506: BATSE Observations
  48. GRB 990506, optical observations
  49. GRB 990506, Optical Observations
  50. GRB 990506 optical observations
  51. GRB 990506 optical observations
  52. GRB 990506, optical observations
  53. GRB990506 observation plan
  54. Refined IPN error box for GRB990506
  55. GRB 990506: Limits on the possible optical transient
  56. GRB 990506, optical observations from +1 to +3 hours
  57. GRB 990506, optical observations
  58. GRB990506 Optical observations
  59. IPN localization of GRB990427
  60. GRB981220 VLBA observations
  61. GRB980425 Optical observations of exponential decline at late time
  62. GRB990321 REFINED IPN ANNULUS
  63. GRB990323 PRECISE IPN POSITION
  64. GRB990321 IPN TRIANGULATION
  65. GRB 990316 Optical Observations
  66. GRB 990316, Radio observations
  67. GRB 990316, Optical observations
  68. GRB990316, Optical observations
  69. GRB 990316 optical observations
  70. GRB990316: simultaneous optical observation
  71. GRB990308 not a new SGR
  72. GRB990308 (Trig. 7457), optical observations
  73. GRB990308, Possible new SGR~0209+70
  74. GRB 981220, radio observations
  75. GRB 990217 Optical Observations
  76. GRB 990217, radio observations
  77. Optical Observations of GRB990217
  78. GRB990123 observations
  79. GRB990123, Optical Observation
  80. GRB 990123: Reduced HST Images
  81. For Immediate Posting to GCN - HST Data GRB 990123 Available
  82. GRB19990123 observations
  83. GRB 990123: Updated Keck Spectroscopy Results
  84. GRB981220, field photometry
  85. GRB 990123 NOT Spectrum Update
  86. GRB990123, Optical observation
  87. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  88. GRB 990123: Publicly available reduced HST images
  89. GRB990123, Upcoming HST Service Observations
  90. GRB990123, 15-GHz limits
  91. GRB 990123: New Constraints on Possible Foreground Galaxies
  92. GRB990123 Optical Observations
  93. GRB990123, Probability of gravitational lensing
  94. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  95. GRB 990123: Continued Radio Observations
  96. GRB990123, Preliminary Lens Search Results
  97. GRB990123, Optical BVRI Observations
  98. GRB 990123: near-infrared observations.
  99. GRB990123, OSSE observations
  100. GRB990123: NIR Observation

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