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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"

43612 results found.

  1. GRB 141229A Swift-BAT observations
  2. GRB 141230A: Nanshan optical obsrvations
  3. GRB 141230A: iPTF Optical Observations and Candidate Afterglow iPTF14jko
  4. GRB 141229A: 1.23m CAHA optical observations
  5. GRB 141229A: Nanshan optical upper limit
  6. GRB 141229A: Swift-XRT observations
  7. Fermi GBM trigger 141229739 is not a GRB
  8. GRB 141229A: Fermi GBM detection
  9. Christmas GRB 141225A: GROND Observations
  10. GRB 141229A Tiled Swift observations
  11. GRB 141229A: MAXI/GSC detection
  12. GRB 141225A: MASTER-SAAO OT light curve
  13. GRB 141225A: TAROT Calern observatory optical observations
  14. GRB 141225A: Swift/UVOT refined analysis
  15. GRB 141225A: Fermi GBM detection
  16. GRB 141225A: very early T60 observations
  17. GRB 141225A: Swift-BAT refined analysis
  18. GRB 141225A: Swift-XRT refined Analysis
  19. GRB 141225A: MASTER-SAAO first OT detection
  20. GRB 141225A: Nanshan very early optical observations
  21. GRB 141225A: Enhanced Swift-XRT position
  22. GRB 141225A: Redshift from OSIRIS at the 10.4m GTC
  23. GRB 141225A: UVOT detection
  24. GRB 141225A: Optical aftergow confirmation
  25. GRB 141225A: LT optical candidate
  26. GRB 141225A: 1.23m CAHA optical observations
  27. GRB 141225A: Swift detection of a burst
  28. GRB 141221A: Keck spectroscopy
  29. GRB 141221A: TAROT La Silla observatory optical observations
  30. Swift XRT and UVOT observations of GRB141222A
  31. Konus-Wind observation of GRB 141222A
  32. GRB 141222A: First MASTER-SAAO optical observation
  33. IPN Triangulation of GRB 141222A (very intense)
  34. GRB 141221A: Continued Skynet PROMPT-CTIO observations
  35. GRB 141222A: Fermi GBM detection
  36. GRB 141221A: Swift/UVOT Detection
  37. GRB 141222A: Fermi-LAT detection
  38. GRB 141215A: further Swift-XRT observations and afterglow detection
  39. GRB 141221A: Fermi GBM observation
  40. GRB 141221A: Swift-XRT refined Analysis
  41. GRB 141221A: Swift-BAT refined analysis
  42. GRB141221A: GROND Afterglow Detection
  43. GRB 141221A: Enhanced Swift-XRT position
  44. GRB 141221A: Skynet PROMPT-CTIO observations of the optical afterglow
  45. GRB 141221A: LCOGT-McDonald optical afterglow observations
  46. GRB141221A: REM afterglow
  47. Konus-Wind observation of GRB 141220A
  48. GRB 141221A: Swift detection of a burst with an optical counterpart
  49. GRB 141220A: Fermi GBM observation
  50. GRB 141220A: Swift-XRT refined Analysis
  51. GRB 141220A: Swift-BAT refined analysis
  52. GRB 141220A: Swift/UVOT Detection
  53. GRB 141220A: Photometry from OSIRIS/GTC
  54. GRB 141220A: LT optical afterglow observations
  55. GRB 141220A: Redshift from OSIRIS at the 10.4m GTC
  56. GRB141220A: 1.23m CAHA I-band observations
  57. GRB 141220A: Swift detection of a burst with an optical afterglow
  58. Fermi Gamma-ray Burst Monitor trigger 440728127 / 141220020 is not a GRB
  59. IPN Triangulation of GRB 141207A
  60. GRB 141207A: Suzaku WAM observation of the prompt emission
  61. GRB 141202A: Suzaku WAM observation of the prompt emission
  62. GRB 141121A: Keck observations
  63. GRB 141215A: Swift-XRT observations
  64. GRB 141215A: Fermi GBM detection
  65. GRB 141215A Tiled Swift observations
  66. Konus-Wind observation of GRB 141215A
  67. IPN Triangulation of GRB 141215A (long/intense)
  68. GRB 141212A iTelescope observation
  69. GRB 141212A: Zadko observatory - Gingin optical observations
  70. Konus-Wind observation of GRB 141212B
  71. GRB 141212B: Swift-XRT refined Analysis
  72. GRB 141212A: VLA upper limit
  73. GRB 141212A: Gemini-N spectroscopy and photometry
  74. GRB 141212B: Swift-BAT refined analysis
  75. GRB 141212A: Swift-BAT refined analysis
  76. GRB 141212B: Enhanced Swift-XRT position
  77. Swift detection of 4U 1700+24 (= V934 Her)
  78. GRB 141212A: Swift-XRT refined Analysis
  79. GRB 141212A: extended object within the XRT error circle
  80. GRB 141212A: Khureltogot optical upper limit
  81. GRB 141212A: 1.23m CAHA I-band observations
  82. GRB 141212B: initial Swift/UVOT observations
  83. GRB 141212B: Swift/XRT preliminary localization
  84. GRB 141212A: Enhanced Swift-XRT position
  85. GRB 141212A: MASTER early optical observations
  86. GRB 141212A: Skynet R-COP Observations
  87. GRB 141212B: Swift detection of a burst
  88. GRB 141212A: Swift detection of a short burst
  89. GRB 141207A: Swift-XRT afterglow candidate detection
  90. GRB 141121A: further VLA observations
  91. Konus-Wind observation of GRB 141207A
  92. GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
  93. GRB141202A: Discovery Channel Telescope Optical Observations
  94. GRB141207A: Discovery Channel Telescope Optical Observations
  95. GRB 141207A: Swift-UVOT Observations
  96. GRB 141207A: Fermi GBM detection
  97. GRB 141207A: Swift-XRT observations
  98. Konus-Wind observation of GRB 141130A
  99. GRB 141207A Tiled Swift observations
  100. GRB 141207A: Fermi-LAT Detection

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