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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 140906A: iPTF optical transient candidates
  2. GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
  3. GRB 140903A: Possible optical variability
  4. GRB 140903A: NOT optical and NIR observations
  5. GRB 140901B: Swift XRT observation
  6. GRB 140903A: FTN observations
  7. GRB 140818B: TShAO optical upper limit
  8. GRB 140903A: ISON-Kislovodsk observations
  9. GRB 140903A: MAXI/GSC upper limit
  10. GRB 140903A: 6 GHz VLA detection
  11. GRB 140903A: Pan STARRS images of the field
  12. GRB 140901B: Fermi GBM detection
  13. GRB 140903A: tentative spectroscopic redshift
  14. GRB 140901B found in ground analysis of BAT data
  15. GRB 140903A: Swift/UVOT Upper Limits
  16. GRB 140903A: Swift-BAT Spectral lag analysis
  17. GRB 140903A: P60 Optical Observations
  18. GRB140903A: Discovery Channel Telescope Optical Detection
  19. GRB 140903A: Swift-BAT refined analysis
  20. GRB 140903A: Swift-XRT refined Analysis
  21. GRB 140903A: Coincident galaxy cluster in archival images
  22. GRB 140903A: Confirmed Swift detection of a short burst
  23. GRB 140903A: Preliminary Swift/XRT localization
  24. GRB 140903A: Swift detection of a possible burst
  25. GRB 140901A: Fermi GBM detection
  26. IPN Triangulation of GRB 140901A (short/hard/very intense)
  27. GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
  28. GRB 140829A: Fermi GBM Detection
  29. GRB 140829A: iPTF optical observations
  30. GRB140818B, the review of the sky area in plate archives
  31. GRB 140828A, Swift-BAT refined analysis
  32. Konus-Wind observation of GRB 140825A
  33. GRB 140828A: Fermi GBM observation
  34. Swift Mission Operations Center Fully Operational
  35. IPN Triangulation of GRB 140825A (very intense/long)
  36. GRB 140828A: Swift detection of a burst
  37. IPN Triangulation of GRB 140824B
  38. Swift Burst Response Reenabled
  39. GRB 140818B: TLS observations
  40. GRB 140824A: optical upper limit in CrAO
  41. GRB 140824B: Swift observations
  42. Fermi TRIGGER_NUM 430645968: MASTER OT inside error box
  43. Swift Mission Operations Center Moving Tomorrow
  44. GRB 140824B: Fermi GBM Detection
  45. GRB 140821A: Fermi GBM Detection
  46. Fermi TRIGGER_NUM 430583595: MASTER OT 20 hours later
  47. Fermi TRIGGER_NUM 430583595: MASTER OT JR011101.13+603337.5 detection
  48. GRB 140824A: NOT optical upper limits
  49. GRB 140824A: OSN optical limit
  50. GRB 140824A: Swift-XRT refined Analysis
  51. GRB 140824A: Swift-BAT refined analysis
  52. GRB 140824A: Enhanced Swift-XRT position
  53. GRB 140824A: MITSuME Ishigakijima upper limits
  54. GRB 140824A: Swift/UVOT Upper Limits
  55. GRB 140824A: Swift detection of a burst
  56. GRB 140817A: NOT optical observations
  57. Fermi GBM Trigger 140819576/ 430148973/ MASTER OT
  58. GRB 140817A: Khureltogot optical upper limit
  59. GRB 140818B: ISON-Kislovodsk and ISON-Burakan optical upper limit
  60. Fermi trigger 430148973: Swift-XRT observation
  61. GRB 140818A: GROND confirmation of afterglow candidate
  62. GRB 140808A/iPTF14eag: AMI 15 GHz detection
  63. GRB140819A: Deep GROND Upper Limits
  64. Fermi 430148973/MASTER candidate: LCO-Sutherland observations
  65. Fermi trigg_num 430148973: OSN I-band observations
  66. GRB 140818B, Swift-BAT refined analysis
  67. Fermi trigg_num 430148973: bright OT inside large error box!
  68. Konus-Wind observation of GRB 140818A
  69. GRB 140818B : Correction to GCN 16713
  70. GRB 140818B: Swift/UVOT Upper Limits
  71. GRB 140818B: Swift-XRT refined Analysis
  72. Radio upper limit on the GRB 140808A with the GMRT
  73. GRB 140818B: Fermi GBM detection
  74. GRB140818B : GROND afterglow candidate
  75. GRB 140818B: Enhanced Swift-XRT position
  76. GRB 140818B: OSN I-band afterglow candidate
  77. GRB 140817A: Swift/UVOT Afterglow Detection
  78. GRB 140818B: Swift detection of a burst
  79. GRB 140818A - Fermi GBM Detection
  80. Swift detection of SAX J1712.6-3739
  81. GRB 140818A: Swift-XRT and UVOT potential afterglow detection
  82. GRB 140818A: Correction to GCN 16702
  83. Konus-Wind observation of GRB 140817A
  84. GRB 140818A Tiled Swift observations
  85. GRB 140818A: MAXI/GSC detection
  86. GRB 140817A: Swift-XRT refined Analysis
  87. GRB 140817A: Fermi GBM Detection
  88. GRB 140817A: Swift-BAT refined analysis
  89. GRB 140817A draft circular on nearby galaxy
  90. GRB 140817A: Enhanced Swift-XRT position
  91. GRB 140817A: Swift-XRT position
  92. GRB 140817A: Swift detection of a burst
  93. GRB 140808A / PTFeag: VLA K-band observations
  94. GRB 140815A: GROND afterglow candidate
  95. Swift Trigger 609694 is probably not an astrophysical source
  96. GRB 140815A: Swift-XRT observations
  97. GRB 140815A: A long GRB detected by INTEGRAL
  98. GRB 140814A: Swift-XRT and UVOT observations
  99. GRB 140814A: MASTER optical follow-up inspection
  100. GRB 140814A: Swift-XRT and UVOT observations

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