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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 141026A: 1.23m CAHA I-band observations
  2. GRB 141026A: GROND observations
  3. GRB 141026A: RATIR Optical Observations
  4. GRB 141026A: P60 early observations
  5. GRB 141026A: Swift detection of a burst
  6. Fermi Gamma-ray Burst Monitor trigger 141025734 is not a GRB
  7. GRB 141020A: AAO optical upper limit
  8. GRB 141020A: Khureltogot optical upper limit
  9. GRB141022A: Fermi GBM Detection
  10. GRB141022B: Fermi GBM Detection
  11. GRB 141022A: Swift/UVOT Upper Limits
  12. GRB 141020A: Mondy optical observations
  13. GRB 141022A: Swift-BAT refined analysis
  14. GRB 141022A: Swift-XRT refined Analysis
  15. GRB141015A iTelescope observation
  16. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  17. GRB 141022A: Swift detection of a burst
  18. GRB 141004A: RATIR Late Time Optical and NIR Observations
  19. GRB 141004A: La Palma late-time observations and possible brightening
  20. GRB 141020A: Swift-BAT refined analysis
  21. GRB 141020A: Swift-XRT refined Analysis
  22. GRB 141020A: 1.4 GHZ observation
  23. GRB 141020A: Swift/UVOT Detection
  24. GRB 141020A: Enhanced Swift-XRT position
  25. GRB 141020B: MAXI/GSC detection
  26. Konus-Wind observation of GRB 141017A
  27. GRB 141020A: Swift detection of a burst with an optical counterpart
  28. GRB 141017A, Swift-BAT refined analysis
  29. GRB 141017A: GROND Afterglow Confirmation
  30. GRB 141015A: Swift-XRT afterglow confirmation and refined Analysis
  31. GRB 141017A: Swift/UVOT Detection
  32. GRB 141015A: MITSuME Akeno upper limits
  33. GRB 141017A: Swift-XRT refined Analysis
  34. GRB 141017A: Enhanced Swift-XRT position
  35. GRB 141017A: Zadko observatory - Gingin optical observations
  36. GRB 141017A: Swift detection of a burst
  37. GRB 141015A: Swift/UVOT Upper Limits
  38. GRB 141015A: MITSuME Okayama upper limits
  39. GRB 141015A: Swift-BAT refined analysis
  40. GRB 141015A: LCO-McDonald observations
  41. GRB 141015A: RATIR Optical Upper Limits
  42. GRB 141015A: Enhanced Swift-XRT position
  43. GRB 141015A: Super-LOTIS early observations
  44. GRB 141015A: ISON-NM early optical observations
  45. GRB 141015A: Swift/XRT localization
  46. GRB 141015A: Swift detection of a burst
  47. Fermi Gamma-ray Burst Monitor trigger 141014781 is not a GRB
  48. Konus-Wind observation of GRB 141011A
  49. IPN Triangulation of GRB 141011A (short/hard)
  50. GRB 141011A: Fermi GBM detection
  51. Trigger 614903: Swift detection of IGR J17544-2619
  52. GRB 141005A: iTelescope.Net T21 Optical Observation
  53. GRB141004A: Host galaxy redshift form GTC
  54. GRB 141005A: Additional P60 imaging and afterglow confirmation
  55. GRB 141004A: Fermi GBM observation
  56. GRB 141004A: GROND observations
  57. GRB 141005A: GROND observations
  58. Konus-Wind observation of GRB 141005A
  59. GRB 141004A: Swift-XRT refined Analysis
  60. GRB 141005A: Swift-XRT refined Analysis
  61. GRB 141005A: Swift/UVOT Upper Limits
  62. GRB 141005A: Swift-BAT refined analysis
  63. GRB 141004A: Swift-BAT refined analysis
  64. GRB141004A: NOT imaging and spectroscopy
  65. GRB 141004A: Swift/UVOT Detection
  66. GRB 141005A: Fermi GBM Detection
  67. GRB 141005A: Enhanced Swift-XRT position
  68. GRB 141004A: RATIR Optical Observations
  69. GRB 141004A: Monte Agliale Observatory optical observations
  70. GRB 141005A: RATIR Optical Observations
  71. GRB 141005A: P60 probable afterglow deteaction
  72. GRB 141004A: Enhanced Swift-XRT position
  73. GRB 141005A: Swift detection of a burst
  74. GRB 141004A: TNG photometric and spectroscopic observations
  75. GRB 141004A: 1.23m CAHA optical observations
  76. GRB 141004A: a long GRB detected by INTEGRAL
  77. GRB 141004A: Swift detection of a burst with an optical counterpart
  78. Swift observations of HD 305560
  79. GRB 140928A: Swift-XRT follow-up observations
  80. GRB 140930B: MASTER early possible OT detection
  81. Swift possible detection of the Be star HD 305560
  82. GRB 140930B: Gemini South Spectroscopy
  83. GRB 140930B: GROND observations
  84. GRB 140930A/MAXI J2259+524: MASTER optical observations
  85. GRB 140930B Swift-BAT refined analysis
  86. GRB 140930B: Swift/UVOT Upper Limits
  87. Konus-Wind observation of GRB 140930B
  88. GRB 140930B: Keck NIR imaging
  89. GRB 140930B: Swift-XRT refined Analysis
  90. GRB 140930B: Enhanced Swift-XRT position
  91. GRB 140928A: MAXI-GSC detection
  92. GRB 140930B: MMT confirmation of the optical afterglow
  93. GRB 140930B: ISON-Kislovodsk observations
  94. GRB 140930B: WHT detection of candidate afterglow
  95. GRB 140930B: 1.23m CAHA optical observations
  96. GRB 140930B: Prompt enhanced Swift-XRT position
  97. GRB 140930B: MASTER early optical observations
  98. GRB 140930B: Swift detection of a short burst
  99. GRB140928A: Gemini-South observation
  100. GRB 140930A/MAXI J2259+524: MAXI-GSC detection

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