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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"
  1. No OT 060420 in MASCOT images
  2. Swift-BAT detection of Mrk 421
  3. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  4. GRB060421: Swift/UVOT observations
  5. GRB 060421: Swift-BAT Refined Analysis
  6. GRB 060421: Swift-XRT refined analysis
  7. GRB 060418: prediction of t_break
  8. GRB060418: optical observations
  9. Konus-Wind observation of GRB 060418
  10. GRB(?)060421:MASTER optical limit
  11. GRB(?)060421 : XRT position
  12. Possible GRB060421: BART limits
  13. GRB(?) 060421: Swift detection of a burst
  14. Erratum of GCN 4983 for GRB 060418 IR follow-up
  15. GRB 060418 : IR afterglow observations
  16. GRB 060418 : Lulin Optical follow-up
  17. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  18. GRB 060418: Radio Observations
  19. GRB060418, BVRcIc field calibration
  20. GRB060418: Swift/UVOT Observations
  21. GRB060418: Optical Observations
  22. GRB 060418: FRAM early afterglow observation
  23. GRB 060418: Refined Analysis of the Swift-BAT burst
  24. VLT/UVES observations of GRB060418
  25. GRB060418: Swift XRT Team Refined Analysis
  26. GRB 060418, SMARTS continuing afterglow observations
  27. GRB 060418: PROMPT Detections
  28. GRB 060418, SMARTS optical/IR afterglow observations
  29. GRB060418: Magellan/MIKE Spectroscopic Redshift
  30. GRB060418 : LT optical afterglow observation
  31. GRB 060418: REM candidate afterglow
  32. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  33. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  34. GRB060413: Swift/UVOT upper limits
  35. GRB 060413: REM NIR Observations
  36. SGR 1900+14: Swift detection of an outburst
  37. GRB 060413: Refined analysis of the Swift-BAT burst
  38. GRB 060413: Watcher UBVR observations
  39. GRB 060413: XRT refined analysis
  40. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  41. GRB 060413: Swift detection of a burst
  42. GRB060403: optical observations
  43. GRB 060403 Optical observations
  44. GRB 060403: MITSuME optical observation
  45. GRB060403: Optical Limit
  46. GRB060403: XRT refined analysis
  47. GRB 060403: Swift/UVOT upper limits
  48. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  49. SGR 1900+14: BAT observations
  50. GRB 060403: Refined analysis of the Swift-BAT burst
  51. GRB060403: Swift XRT refined position
  52. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  53. GRB 060403: Swift detection of a burst
  54. HETE trigger H4044: RTT150 optical observations
  55. GRB060331: Swift/UVOT upper limits
  56. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  57. Swift XRT observations of the HETE transient H4043
  58. HETE Trigger 4043: ROTSE-III Optical Limits
  59. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  60. H4043, an unusual high-energy transient observed by HETE
  61. GRB 060322: LNA optical limit
  62. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  63. INTEGRAL and XMM ToO observations of SGR1900+14
  64. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  65. SGR 1900+14: Swift-BAT detection of a bright outburst
  66. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  67. GRB 060323 : WIDGET simultaneous optical observations
  68. GRB 060323: Early optical observation at Xinglong
  69. GRB060218, optical observations
  70. GRB 060322: Confirmation of Swift XRT afterglow
  71. GRB 060211A: optical observation
  72. GRB060323: optical limit
  73. GRB060211B: optical observation
  74. SGR 1900+14: CORRECTION to GCN 4923
  75. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  76. SGR 1900+14: Swift detection of renewed activity
  77. GRB060323: NOT optical observations
  78. GRB 060322: IAC80 optical observations
  79. GRB 060322: Swift XRT afterglow candidate
  80. GRB060323: P60 Observations
  81. GRB 060323: Swift/UVOT Observations
  82. GRB 060323: optical afterglow confirmed
  83. GRB060323: NOT observations
  84. GRB 060323: Optical Observations
  85. GRB 060323: Tautenburg OT candidate retraction
  86. GRB 060323: Refined analysis of the Swift-BAT burst
  87. GRB 060323: optical observations at TNG
  88. GRB 060323: Swift XRT refined analysis
  89. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  90. GRB 060323: Swift/XRT position
  91. GRB 060322: Refined analysis of the Swift-BAT burst
  92. GRB060323, optical observation
  93. GRB060323 - SDSS Pre-Burst Observations
  94. GRB 060323: Swift detection of a burst with a possible optical afterglow
  95. GRB 060322: Swift-BAT detection of a 200-sec burst
  96. GRB060219: optical observation
  97. GRB060206: optical observation
  98. GRB060218/SN2006aj: optical observations
  99. GRB 060218/SN 2006aj, LNA optical observation
  100. GRB060218: Refined photometric calibration of comparison stars

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