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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"

40654 results found.

  1. GRB990705, VLT-FORS1 observations of the host galaxy
  2. GRB010222, late-time optical observation
  3. GRB 010222 - HEGRA GeV/TeV Observations
  4. Congratulate Scott on the 1000th GRB Coordinates Network Circular!
  5. GRB010222: Chandra X-ray Observatory Observation
  6. GRB010222: Sub-millimeter vanishing act
  7. GRB010222 - Optical observation
  8. GRB 010222, Optical Observations
  9. GRB010220 optical obsercations
  10. GRB010222 - Optical observation
  11. GRB 010222: High-Resolution Keck Spectroscopy
  12. GRB010222: Optical observation and decay
  13. GRB 010214, I-band data
  14. Sub-millimeter Excess/GRB 010222
  15. GRB 010222
  16. GRB 010222 HST/Chandra TOO
  17. GRB010222 further R-band photometry
  18. GRB010222 Optical observations
  19. GRB 010222: Keck Spectroscopy
  20. GRB010214, field photometry
  21. GRB010222, field photometry
  22. GRB010222 further R-band photometry
  23. GRB010222, possible increase of optical decay slope
  24. GRB 010222 Kyoto optical observation
  25. GRB010222: fading behavior
  26. GRB 010222 BV optical observations
  27. GRB010220, Optical Observations
  28. GRB010222 R-BAND OBSERVATION
  29. GRB 010220: Near-IR Observations
  30. GRB010214 follow-up from Hanle
  31. GRB 010222: Near-IR Observations
  32. GRB 010222: Optical Observations
  33. GRB 010222, Decay Slope Confirmed
  34. GRB010222: Another absorption line system
  35. GRB010222: Optical decay slope
  36. GRB 010214, Optical Observations
  37. GRB010222: Sub-millimeter detection
  38. GRB010222: R-band fading behavior
  39. GRB010222: Optical Observations
  40. GRB010222, radio observations
  41. GRB010222, optical observations
  42. GRB010222: BeppoSAX/NFI Observations
  43. Redshift of the Optical Transient of GRB010222
  44. GRB010214B,Gamma Ray Observations
  45. GRB010222: possible optical counterpart
  46. GRB010222
  47. GRB010220, Radio and Optical Observations
  48. GRB 010220, simultaneous optical observations
  49. GRB010220: BeppoSAX WFC and GRBM preliminary data
  50. GRB010214, candidate optical afterglow
  51. GRB010214, optical observations
  52. GRB010214: BeppoSAX WFC and GRBM preliminary data
  53. GRB 010214: X-Ray afterglow
  54. GRB 010214, Optical Observations
  55. GRB 010214 optical observation
  56. GRB010213, Radio Observations
  57. GRB010213 Optical Observation
  58. GRB010213, Radio Observations
  59. J-Band Observation of GRB 010214.
  60. GRB010214, Radio Observations
  61. GRB010214, optical observations
  62. GRB010213, optical observations
  63. GRB010213, Near-IR observations
  64. Possible InfraRed Transient of GRB 010214.
  65. GRB010214 Optical Observation
  66. GRB010214: BeppoSAX/NFI Observations
  67. GRB010213 (HETE) TAROT observations
  68. GRB 010214, optical observations
  69. GRB010213 detected by HETE
  70. HETE Status
  71. GRB010126 opt. obs.
  72. IPN/RXTE TRIANGULATION OF GRB010126
  73. GRB010126, TNG R-band observations
  74. GRB010126 Optical Observations
  75. GRB010126 optical observations
  76. GRB010126: Optical observations
  77. IPN/RXTE TRIANGULATION OF GRB010126
  78. GRB 010119, optical observations
  79. GRB010119: Optical observations
  80. Optical Observations of GRB 001018 at Keck
  81. GRB010119, Radio observations
  82. Optical observations of GRB 001018 with JCAM
  83. IPN TRIANGULATION OF GRB010109
  84. IPN TRIANGULATION OF GRB010109
  85. GRB010103, optical observations
  86. IPN triangulation of GRB010103
  87. GRB 001204: Ks observations
  88. H band observation of GRB 001212
  89. IPN triangulation of GRB001219
  90. GRB 001212 Optical Observation
  91. GRB 001212 Optical Observation
  92. GRB 001212 optical observation
  93. GRB 001212 possible OA
  94. IPN triangulation of GRB001212
  95. GRB001204: Optical observations
  96. Confirmation of IPN position for GRB001204
  97. GRB001204, Radio observations
  98. IPN triangulation of GRB001204 (short/hard)
  99. GRB 001105, further optical observations
  100. GRB001120: Gunn-i observations

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