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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"

21763 results found.

  1. GRB990704 radio and optical observations
  2. GRB990704
  3. GRB990704, optical observations
  4. GRB 990627, radio observations
  5. Late-time HST/STIS Observation of GRB 990123
  6. Optical Observations of GRB 990506
  7. GRB990527 Optical Observations
  8. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  9. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  10. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  11. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  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. radio observations of X-ray/GRB transient field
  16. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  17. Optical report on X-ray/GRB transient
  18. GRB 990510: optical linear polarization
  19. GRB 990510: optical observations
  20. GRB990510, VI observations
  21. GRB 990510: BATSE Observations
  22. GRB 990510: BeppoSAX/GRBM observations
  23. GRB 990510 optical observations
  24. GRB 990506 Radio Observations
  25. GRB 990123, optical monitoring
  26. GRB 990506, optical observations
  27. GRB 990506, Optical Observations
  28. GRB 990506 optical observations
  29. GRB 990506, optical observations
  30. GRB 990506, optical observations from +1 to +3 hours
  31. GRB 990506, optical observations
  32. GRB990506 observation plan
  33. GRB981220 VLBA observations
  34. GRB 990316 Optical Observations
  35. GRB 990316 optical observations
  36. GRB990316: simultaneous optical observation
  37. GRB990316 - Optical null results
  38. GRB 990123, Field Photometry
  39. GRB 990217 Optical Observations
  40. GRB 990217, radio observations
  41. BATSE Flight Anomaly
  42. GRB990123 observations
  43. GRB990123, Optical Observation
  44. GRB 990123: Discovery of the Probable Host Galaxy
  45. GRB 990123: Reduced HST Images
  46. GRB19990123 observations
  47. GRB 990123: BVRI standards in the field
  48. GRB981220, field photometry
  49. GRB990123, Optical observation
  50. GRB990123, 15-GHz limits
  51. GRB 990123: New Constraints on Possible Foreground Galaxies
  52. GRB990123 Optical Observations
  53. GRB990123, Probability of gravitational lensing
  54. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  55. GRB990123, Preliminary Lens Search Results
  56. GRB990123, Optical BVRI Observations
  57. GRB 990123: near-infrared observations.
  58. GRB990123, OSSE observations
  59. GRB990123: NIR Observation
  60. "GRB 990123: New BV Observations"
  61. GRB 990123: New Optical Observations, Decay Measure
  62. GRB 990123 Optical Follow-Up
  63. GRB 990123: Possible Gravitationally Lensed Burst?
  64. GRB990123, optical observation
  65. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  66. GRB 990123 r-band photometry
  67. GRB 990123 Optical Follow-up
  68. GRB990123, early optical counterpart detection
  69. GRB 990123, Radio observations
  70. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  71. Possible identification of SN1999E with GRB980910
  72. Optical Observations of GRB 981220
  73. GRB 981226: radio variable
  74. GRB 981226 Optical Observations
  75. GRB981226 BeppoSAX follow up
  76. GRB 981226
  77. GRB 981226 optical observations
  78. GRB981220 B, R and I band observations
  79. GRB 981220:Optical Observations
  80. GRB 981226 optical observations
  81. GRB 981220, radio observations
  82. GRB 981220: BeppoSAX/GRBM results
  83. GRB981220 Optical Observations
  84. GRB 981220
  85. GRB 980326/Host Galaxy
  86. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  87. BeppoSAX NFI Observation of GRB980425
  88. GRB980329 R,I flux calibration and R,I,K upper limits
  89. GRB980425 Optical Follow-up
  90. GRB980425: X-ray revised positions
  91. GRB980703 Very Long Baseline Interferometry
  92. GRB970508 optical observations
  93. GRB980519, Optical Observations
  94. GRB980703 - BeppoSAX/GRBM detection
  95. GRB980703 optical photometry
  96. GRB 980703: BATSE Observations
  97. GRB980703 optical observations
  98. GRB980703: Radio transient
  99. GRB980703 Transient Optical Follow-Up
  100. GRB980703: LOTIS observation at early times

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