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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"

26050 results found.

  1. GRB060210: Gemini absorption spectroscopy
  2. GRB060210: Early Optical Observations
  3. GRB 060210: optical evolution
  4. GRB060210:Faulkes Telescope North Afterglow Confirmation
  5. GRB 060210: candidate afterglow
  6. GRB 060210: Swift detection of a burst
  7. GRB060210: Optical afterglow
  8. GRB 060206: Swift/UVOT Observations
  9. Swift-BAT trigger 180931 is not a GRB
  10. GRB060209: RTT150 optical observations
  11. GRB 060209 : TAROT optical observation
  12. GRB 060209(?): Swift-BAT detection of a possible burst
  13. GRB 060206: near-infrared observations (JK' imaging)
  14. GRB 060206: WSRT Radio Observations
  15. GRB 060203: Swift/UVOT upper limits
  16. GRB 060206: TTT Observations
  17. GRB 060206: More PROMPT Detections
  18. GRB 060121 : WIDGET Pre-trigger limit
  19. GRB 060206: Tenagra II Observations
  20. GRB 060206: PROMPT Detections
  21. Retraction of orphan GRB afterglow candidate
  22. GRB060204a: Swift XRT Source is not GRB Afterglow
  23. GRB 060206: optical observations at Asiago
  24. Orphan GRB Afterglow candidate
  25. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  26. GRB 060206: Subaru/FOCAS optical spectroscopy
  27. GRB 060206: IR Detection of the Afterglow
  28. GRB 060206: Lick 3m Spectroscopy
  29. GRB 060204A: ROSAT Pointing
  30. GRB 060206: Super-LOTIS observations
  31. GRB060204A: Swift/UVOT observations
  32. GRB 060206: Swift-BAT refined analysis
  33. GRB 060206 : Lulin optical observations
  34. GRB060206: Swift XRT Refined Analysis
  35. GRB060206: Liverpool Telescope observation
  36. GRB 060206: Spectroscopic Redshift
  37. GRB060206: P60 Optical Observations
  38. GRB 060206: KAIT observations
  39. GRB060206: Swift XRT Position
  40. GRB060206: SARA Detection
  41. GRB 060206: RAPTOR observations of afterglow candidate variability.
  42. GRB 060206: High redshift burst
  43. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  44. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  45. GRB060206: Optical afterglow
  46. GRB060206: Swift-BAT detection of a burst
  47. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  48. BAT GRB 060204C is probably not a GRB
  49. GRB 060204B: BVRi-band detections of optical afterglow
  50. GRB 060204A: Swift XRT upper limit
  51. GRB060204B: Swift/UVOT refined analysis
  52. GRB 060204C: optical observations
  53. Swift XRT Observation of GRB 060204C
  54. GRB 060204B: Swift-BAT refined analysis
  55. GRB 060204B: ART early limit
  56. GRB060204B: Swift XRT Team Refined Analysis
  57. GRB 060204C: OSN limits
  58. GRB 060204b: Keck/LRIS Afterglow Confirmation
  59. GRB 060204C: Liverpool Telescopes optical limit
  60. GRB 060204C: ROTSE-III Optical Limits
  61. GRB 060204C: Swift-BAT detection of a burst
  62. GRB 060124: Radio Observations
  63. GRB060204B: Faulkes OT candidate
  64. GRB 060204B: ART optical limit
  65. GRB060204B, optical observation
  66. GRB060204B - SDSS pre-burst observations
  67. GRB 060203: Swift-BAT refined analysis
  68. GRB 060204B: Swift detection of a burst
  69. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  70. GRB 060203: RTT150 optical observations
  71. GRB060203: Swift XRT Team Refined Analysis
  72. GRB060203 - Swift UVOT observation
  73. Swift-BAT trigger is GRB 060203
  74. GRB 060203: IR Counterpart
  75. GRB060203: Observations with SARA
  76. GRB 060203: P60 Confirmation of Optical Afterglow
  77. Possible GRB 060203: candidate optical counterpart
  78. Swift BAT Trigger 180151: Swift XRT source detection
  79. Possible GRB 060203: optical observations at Asiago
  80. Swift-BAT trigger 180151 is unknown origin at this time
  81. GRB 060202: GETS observation
  82. GRB 060202: Gemini-N J, H, K_s observations
  83. GRB 060202 : Kiso B and R band limit
  84. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  85. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  86. GRB 060202: Refined analysis of the Swift-BAT burst
  87. GRB060202, optical observation
  88. GRB 060202: Swift/UVOT upper limits
  89. GRB 060202: Swift XRT Team Refined Analysis
  90. GRB 060202 : Lulin R and I band limit
  91. GRB060202: Faulkes North observation
  92. GRB 060202: Swift detection of a burst
  93. GRB 060121: Gemini Late-time Observations
  94. GRB 060130: Swift/XRT observation
  95. GRB 051211A: MDM Observations
  96. GRB 060123: Gemini spectroscopy of the putative host galaxy
  97. GRB 060123: VLA Radio Observations
  98. Possible GRB 051221B: MDM Correction
  99. GRB 060121: Confirmation of NIR Afterglow
  100. GRB060124: optical observation

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