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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"

20120 results found.

  1. GRB060218: Radio Afterglow Discovery
  2. GRB060219: SDSS pre-burst observations
  3. GRB 060219: Swift-BAT detection of a weak burst
  4. Oddball GRB 060218, transient or GRB?
  5. Brightening of the Optical Counterpart of the Possible GRB 060218
  6. GRB 060218: Pre-burst detection of a possible host galaxy
  7. GRB 060218A: ROTSE-III Possible Optical Flare
  8. GRB 060211B: Swift/UVOT Upper Limits
  9. GRB060218 : SDSS pre-burst observations
  10. GRB 060218: Swift XRT Position
  11. GRB 060213: optical afterglow not confirmed
  12. Swift UVOT observations of GRB060213
  13. GRB060213: Swift XRT observations and possible afterglow candidate
  14. Konus-Wind observation of bright hard GRB 060213
  15. GRB 060213: IPN localization
  16. GRB060211B: REM optical and NIR observations
  17. GRB 060211A: Further refined analysis of the Swift burst
  18. GRB 060210: ARC NIR Detection of Afterglow and Possible Host Galaxy
  19. GRB 060211b: P60 Observations
  20. GRB 060211B: Swift/BAT refined analysis
  21. GRB060210: Swift/UVOT Upper Limits
  22. GRB 060210: Optical Observations
  23. GRB 060211: ROTSE-III Optical Limits
  24. GRB 060211: Swift detection of a long burst
  25. GRB060210: Optical Observations
  26. GRB060210: Early Optical Observations
  27. GRB 060210: optical evolution
  28. GRB 060210: Swift detection of a burst
  29. GRB060210: Optical afterglow
  30. GRB 060209 : TAROT optical observation
  31. GRB 060203: Swift/UVOT upper limits
  32. GRB 060206: TTT Observations
  33. GRB 060121 : WIDGET Pre-trigger limit
  34. GRB060204a: Swift XRT Source is not GRB Afterglow
  35. Orphan GRB Afterglow candidate
  36. GRB 060206: IR Detection of the Afterglow
  37. GRB 060204A: ROSAT Pointing
  38. GRB 060206: Super-LOTIS observations
  39. GRB060204A: Swift/UVOT observations
  40. GRB060206: SDSS Pre-Burst Observations
  41. GRB 060206: High redshift burst
  42. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  43. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  44. GRB060206: Optical afterglow
  45. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  46. GRB060203: WHT Z-band observations
  47. BAT GRB 060204C is probably not a GRB
  48. GRB060204C: optical observation
  49. GRB 060204A: Swift XRT upper limit
  50. GRB 060204A: FRAM optical observations
  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. GRB 060204b: Keck/LRIS Afterglow Confirmation
  57. GRB 060204C: Liverpool Telescopes optical limit
  58. GRB 060204C: ROTSE-III Optical Limits
  59. GRB 060204C: Swift-BAT detection of a burst
  60. GRB060204B, optical observation
  61. GRB060204B - SDSS pre-burst observations
  62. GRB 060204B: Swift detection of a burst
  63. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  64. GRB 060203: RTT150 optical observations
  65. Swift-BAT trigger is GRB 060203
  66. GRB 060203: IR Counterpart
  67. GRB060203: Observations with SARA
  68. GRB 060203: P60 Confirmation of Optical Afterglow
  69. Possible GRB 060203: optical observations at Asiago
  70. GRB 060202: Gemini-N J, H, K_s observations
  71. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  72. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  73. GRB060202, optical observation
  74. GRB 060202: Swift/UVOT upper limits
  75. GRB 060202: Swift detection of a burst
  76. GRB 060121: Gemini Late-time Observations
  77. GRB 060130: PROMPT Observations
  78. GRB060130: Further R-band imaging
  79. GRB 060130: Swift/XRT observation
  80. GRB060130: Optical imaging
  81. GRB060130: REM infrared observations
  82. GRB 060130, SMARTS optical observations
  83. GRB 060130: FRAM optical observations
  84. GRB 060121: Confirmation of NIR Afterglow
  85. GRB 060123: Swift refined analysis of an unusual GRB
  86. GRB060124, BVRcIc field calibration
  87. GRB060105: refined analysis of the Suzaku observation
  88. GRB 060121: Probable Detection of NIR Afterglow
  89. GRB 060116 HST observations
  90. Konus-Wind observation of GRB 060124
  91. GRB 060124: ART optical limits during the burst
  92. GRB060123: Optical and IR Imaging
  93. GRB 060123: P200 Observations
  94. GRB 060124: R band Observations
  95. GRB 060124 : Optical observation at Xinglong and Kiso
  96. GRB060123: SDSS pre-burst observations
  97. GRB 060123: Swift detection of a very long, faint burst
  98. GRB 060121: OHP optical limits
  99. GRB 060124: TAROT optical limits
  100. GRB060124, optical observation

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