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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"

12318 results found.

  1. GRB 060306: Swift detection of a bright burst
  2. GRB 060218 : GMRT observation [Correction and Improvement]
  3. GRB 060223b: Swift/UVOT Upper Limits
  4. GRB 060218 : Radio upper limits from GMRT
  5. GRB 060204B: GETS early limit
  6. GRB 060223B: ART optical limits
  7. GRB 060223a: Swift/UVOT refined analysis
  8. GRB 060223: Swift/UVOT Confirmation of Optical Afterglow
  9. GRB 060219: Swift/UVOT Upper Limits
  10. GRB 051221B: Swift-XRT Team Refined Analysis
  11. GRB 060219: Swift-BAT detection of a weak burst
  12. GRB 060211B: Swift/UVOT Upper Limits
  13. Swift UVOT observations of GRB060213
  14. GRB060213: MASTER final result
  15. GRB 060211b: WIRO NIR Observations
  16. GRB060213:_MASTER_optical_observation
  17. GRB 060211a: WIRO NIR Observations
  18. GRB060211B: REM optical and NIR observations
  19. GRB060210: Swift/UVOT Upper Limits
  20. GRB 060211B: Swift-BAT detection of a burst
  21. GRB 060211: Swift detection of a long burst
  22. GRB 060210: Swift detection of a burst
  23. GRB 060206: Swift/UVOT Observations
  24. GRB060209A: MASTER optical observation
  25. GRB 060209(?): Swift-BAT detection of a possible burst
  26. GRB 060203: Swift/UVOT upper limits
  27. GRB060204a: Swift XRT Source is not GRB Afterglow
  28. GRB 060206: Lick 3m Spectroscopy
  29. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  30. GRB 060204A: Swift XRT upper limit
  31. GRB060204B: Swift/UVOT refined analysis
  32. Swift XRT Observation of GRB 060204C
  33. GRB060204B, optical observation
  34. GRB 060204B: Swift detection of a burst
  35. GRB060203 - Swift UVOT observation
  36. GRB 060202: GETS observation
  37. GRB 060202: Swift/UVOT upper limits
  38. GRB 060202: Swift detection of a burst
  39. GRB060130: Further R-band imaging
  40. GRB 060130: Swift/XRT observation
  41. GRB060124: optical observation
  42. GRB 060116 HST observations
  43. GRB 060123: Swift detection of a very long, faint burst
  44. GRB060124:MASTER optical observation
  45. GRB 060121: Swift/UVOT upper limits
  46. GRB060108: photometric redshift determination
  47. GRB 060116: Swift/UVOT upper limits
  48. GRB060115: REM observations
  49. GRB 060116: Swift-BAT detection of a burst
  50. GRB 060115: Swift/UVOT upper limits
  51. GRB 060114: REM observations
  52. GRB 060114: Swift/UVOT Observations
  53. GRB 060114: Swift XRT upper limit
  54. GRB 060111A: refined UVOT anaysis
  55. GRB060111A: RTT150 optical observations
  56. GRB 060111: Swift detection of a burst
  57. GRB 060108: z-band imaging from Gemini-North
  58. GRB 060110: Super-LOTIS observations
  59. GRB 060109: Swift/UVOT upper limits
  60. GRB 060108: ISAS early observations and near IR upper limit
  61. Swift UVOT correction to GCN 4455
  62. GRB 060109: Swift Detection of a long burst
  63. GRB 060108: Mitsume optical observations
  64. GRB 060108: Swift/UVOT upper limits
  65. GRB060108: Swift detection of its 100th GRB
  66. GRB 060105: MDM Observation
  67. GRB 060105: ISAS observations and near IR upper limit
  68. GRB 060105: Swift/UVOT upper limits
  69. GRB 060105: Mitsume optical observations
  70. GRB 060102 - no XRT afterglow
  71. GRB060105: Swift detection of a bright long burst
  72. GRB051211B: optical observations
  73. GRB 051227: optical observation
  74. GRB 051227: Swift/UVOT Upper Limits (Possible U-band
  75. GRB051117B: optical observation
  76. GRB 051221A: MDM Optical Observations
  77. GRB 051221A: Refined spectral and temporal analysis of the Swift-BAT short hard burst
  78. GRB 051221B: TAROT optical limits
  79. GRB 051221A: RAPTOR Fading Counterpart Constraint
  80. GRB 051221B: BOOTES optical observations.
  81. Swift-BAT detection of a possible burst
  82. GRB 051221: Swift/UVOT upper limits
  83. GRB 051221: Swift detection of a bright short burst
  84. GRB051211A: possible optical candidate
  85. GRB 051211A: Swift/UVOT upper limits
  86. GRB 051211B: Swift/UVOT upper limits - correction
  87. GRB 051211B: Swift/UVOT upper limits
  88. GRB 051211A and GRB051211B: BOOTES simultaneous observations
  89. GRB 051210: Swift/UVOT upper limits
  90. GRB 051211: Swift XRT upper limit
  91. GRB051117B: optical observation
  92. GRB051117B: Swift XRT refined analysis
  93. GRB051117b: No Swift/UVOT Detection
  94. GRB 051109B: GAO 150cm telescope Optical limit
  95. GRB 051109B : Nainital upper limits
  96. GRB050925: analysis of the XMM-Newton observation
  97. GRB 051109A Milagro GeV/TeV Observations
  98. GRB/SGR 050925: XMM-Newton ToO observation
  99. GRB051111: Swift/UVOT Observations
  100. GRB 051103 Milagro GeV/TeV Observations

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