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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"

24594 results found.

  1. Optical Observations of GRB 990506
  2. GRB990527 Optical Observations
  3. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  4. Late Afterglows of GRBs 990510, 990123
  5. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  6. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  7. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  8. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  9. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  10. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  11. radio observations of X-ray/GRB transient field
  12. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  13. Optical report on X-ray/GRB transient
  14. radio detection of X-ray/GRB transient
  15. BeppoSAX: A new fast X-ray transient
  16. GRB 990510: optical observations
  17. GRB 990510: optical linear polarization
  18. GRB 990510: optical observations
  19. GRB990510: X-ray afterglow
  20. GRB 990510: Broad Band Break
  21. GRB 990510: BATSE Observations
  22. GRB 990510: BeppoSAX/GRBM observations
  23. GRB990510 optical observations
  24. GRB 990510 optical observations
  25. GRB 990506 Radio Observations
  26. GRB 990123, optical monitoring
  27. GRB 990506: BATSE Observations
  28. GRB 990506, optical observations
  29. GRB 990506, Optical Observations
  30. GRB 990506 optical observations
  31. GRB 990506, optical observations
  32. GRB 990506, armchair astronomy
  33. GRB 990506, optical observations from +1 to +3 hours
  34. GRB 990506, optical observations
  35. GRB990506 observation plan
  36. IPN localization for GRB990506
  37. GRB990323 PRECISE IPN POSITION
  38. GRB 990316 Optical Observations
  39. GRB 990316 optical observations
  40. GRB990316: simultaneous optical observation
  41. GRB990316 - Optical null results
  42. GRB990308 not a new SGR
  43. GRB 990308a and GRB 990308b
  44. GRB990308, Possible new SGR~0209+70
  45. GRB 990123, Field Photometry
  46. GRB 990217 Optical Observations
  47. BATSE Flight Anomaly
  48. GRB990217: BeppoSAX/GRBM data
  49. GRB990123 observations
  50. GRB990217 Optical observation
  51. GRB990123, Optical Observation
  52. GRB 990123: Discovery of the Probable Host Galaxy
  53. GRB 990123: Reduced HST Images
  54. GRB19990123 observations
  55. GRB 990123: BVRI standards in the field
  56. GRB981220, field photometry
  57. GRB990123, Optical observation
  58. GRB990123, 15-GHz limits
  59. GRB 990123: New Constraints on Possible Foreground Galaxies
  60. GRB990123 Optical Observations
  61. GRB990123, Probability of gravitational lensing
  62. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  63. GRB990123, Preliminary Lens Search Results
  64. On the Lensing Interpretation of GRB 990123
  65. Search for Potential Images of GRB 990123
  66. Search for Potential Images of GRB 990123
  67. GRB990123, Optical BVRI Observations
  68. GRB 990123: near-infrared observations.
  69. GRB990123, OSSE observations
  70. GRB990123: NIR Observation
  71. GRB990123, ASCA X-ray observation of afterglow
  72. "GRB 990123: New BV Observations"
  73. GRB 990123 Optical Follow-Up
  74. GRB 990123: BATSE Observations
  75. GRB990123 Optical Observations
  76. GRB 990123: New Optical Observations, Decay Measure
  77. GRB 990123 Optical Follow-Up
  78. GRB 990123: Possible Gravitationally Lensed Burst?
  79. GRB990123, optical observation
  80. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  81. GRB990123, Optical observation
  82. GRB 990123: Optical Decay Slope
  83. GRB 990123 r-band photometry
  84. GRB 990123 Optical Follow-up
  85. GRB990123, early optical counterpart detection
  86. GRB990123 Optical Observation
  87. Possible identification of SN1999E with GRB980910
  88. Optical Observations of GRB 981220
  89. GRB 981226: radio variable
  90. GRB981220
  91. GRB981220, Correction to GCN 179
  92. GRB 981220 Optical observations
  93. GRB 981226 Optical Observations
  94. GRB 981220 and GRB 981226, optical observations
  95. GRB981226 Optical Observations
  96. GRB981226 BeppoSAX follow up
  97. GRB 981226
  98. GRB 981226 optical observations
  99. GRB981220 B, R and I band observations
  100. Optical Observations of GRB981226

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