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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. GRB 060717, optical observation
  2. GRB 060717: Swift detection of a burst
  3. GRB060714: correction to GCN 5324
  4. GRB060714: optical observations
  5. GRB 060714, SMARTS optical/IR afterglow observation
  6. GRB 060714 : Liverpool Telescope Observations
  7. GRB 060714: Swift XRT refined analysis
  8. GRB 060714: OA redshift
  9. GRB 060708: VLT spectroscopy
  10. GRB060708: MARGE low resolution spectrum observations
  11. GRB060714: optical observations
  12. Swift-BAT trigger 219136 is not a GRB
  13. Correction to Circular 5314: Circular refers to GRB 060714
  14. GRB060707 possible optical confirmation
  15. Swift trigger 219136 is probably not a GRB
  16. GRB 060714, optical observation
  17. GRB 060714: Swift detection of a burst with an UVOT optical afterglow
  18. GRB 060605: SkyNet Optical Limits
  19. GRB060712: P60 Observations
  20. GRB 060712: XRT refined analysis
  21. GRB 060712: Swift/UVOT Upper Limits
  22. GRB060526: optical observations
  23. GRB 060712: XRT refined position
  24. GRB 060712: Refined analysis of the Swift-BAT burst
  25. GRB060712: MASTER optical observation
  26. GRB120706: MASTER optical observation
  27. GRB 060712: Swift detection of a burst
  28. Host galaxy of GRB050904: 250 GHz upper limit with MAMBO at the IRAM 30m
  29. GRB 060708: PROMPT Optical Limits
  30. GRB 060707: OA fading and redshift
  31. GRB 060708: Swift-XRT refined analysis
  32. GCN 060708: Swift-UVOT Observations
  33. GRB 060708: Refined analysis of the Swift-BAT burst
  34. GCN 060707: Swift-UVOT observations
  35. GRB 060707: Swift-XRT refined analysis
  36. GRB 060708: Swift detection of a burst with an UVOT countpart
  37. GRB060707 possible optical confirmation
  38. GRB 060707: BOOTES-IR optical afterglow candidate
  39. GRB 060707: Refined analysis of the Swift-BAT burst
  40. GRB 060707: BOOTES-IR optical observation
  41. GRB060614: Possible SN Bump in UVOT U Band Light Curve
  42. GRB 060707: Swift detection of a burst
  43. GRB 060515: Upper Limit on Host Galaxy
  44. GRB 050223: Magellan redshift
  45. GRB 060614: SMARTS host galaxy observations
  46. GRB 060614: Detection of a Possible, Late-Time Rebrightening
  47. Correction to GCN 5278 & GCN 5279 (GRBs 060105 & 060109)
  48. GRB 060109: Upper Limit on Host Galaxy
  49. GRB 060105: Upper limit on Host Galaxy
  50. GRB060614: Detection of the host galaxy but no supernova emission
  51. GRB 060614: redshift confirmation
  52. GRB 060614: Redshift
  53. Swift-BAT trigger 215279 is not a GRB
  54. Trigger 215279: Swift detection of a possible burst (GRB 060619)
  55. GRB060614: Optical observations
  56. GRB 060614: spectroscopy
  57. GRB050326: Host Galaxy Candidates
  58. GRB050124: Possible Host Galaxy
  59. GRB050223: Host Galaxy
  60. GRB060512: near IR observations
  61. GRB060526: optical observations
  62. GRB 060614: pseudo-z from spectral parameters of the prompt emission
  63. Konus-Wind observation of GRB 060614
  64. GRB060605: optical observation
  65. The Unusually Long-Lived Afterglow of GRB 060614
  66. GRB 060614: optical observations
  67. GRB 060605, optical observations
  68. GRB 060614, SMARTS optical/IR afterglow observation
  69. GRB060614: SSO 1m observations
  70. GRB060614: Watcher observation
  71. GRB 060614: Swift-BAT refined analysis
  72. GRB 060614: Swift/UVOT Observations
  73. GRB060614: Swift-XRT refined analysis
  74. GRB 060604, optical observations
  75. GRB 060614: Swift detection of a burst with a bright optical and X-ray counterpart
  76. GRB 060602A: Swift/XRT analysis
  77. BAT Trigger #214277 is SGR 1900+14
  78. GRB 060610: KAIT observations
  79. GRB 060607: RTT150 optical observations
  80. GRB 070706B: Watcher upper limit
  81. GRB 060607B: Swift-BAT Refined Analysis
  82. GRB060602A: Swift/UVOT upper limits
  83. GRB 060607B: Swift detection of a burst
  84. GCN 060607: Swift-UVOT obswervations.
  85. GRB 060607: Swift-BAT Refined Analysis
  86. GRB 060607: optical limit by "Pi of the Sky"
  87. GRB 060607: Swift-XRT Team refined analysis
  88. GRB 060607: IR observations
  89. GRB 060502B: A Bright Early-type Galaxy as Putative Host of the Short Burst
  90. VLT/UVES observations of GRB 060607
  91. GRB 060607: PROMPT Observations
  92. GRB 060605: RTT150 optical observations
  93. GRB 060607: REM NIR afterglow
  94. GRB 060607: Swift detection of a burst with bright optical counterpart
  95. GRB 060522: PROMPT Optical Limits
  96. GRB 060605 BAT refined analysis
  97. GRB 060605: Xinglong TNT optical observations
  98. GRB060602B : REM infrared observations
  99. GRB060605: Swift/UVOT detections
  100. GRB 060605: Swift-XRT Team refined analysis

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