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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"

19093 results found.

  1. GRB 141215A: further Swift-XRT observations and afterglow detection
  2. GRB 141221A: Fermi GBM observation
  3. GRB 141220A: MITSuME Akeno upper limits
  4. GRB 141221A: Swift-XRT refined Analysis
  5. GRB141221A: GROND Afterglow Detection
  6. GRB 141221A: Enhanced Swift-XRT position
  7. GRB 141221A: Skynet PROMPT-CTIO observations of the optical afterglow
  8. GRB141221A: REM afterglow
  9. GRB 141221A: Swift detection of a burst with an optical counterpart
  10. GRB 141220A: Fermi GBM observation
  11. GRB 141220A: MITSuME Okayama upper limits
  12. GRB 141220A: Swift-XRT refined Analysis
  13. GRB 141220A: Swift/UVOT Detection
  14. GRB141220A: 1.23m CAHA I-band observations
  15. GRB 141220A: Swift detection of a burst with an optical afterglow
  16. IPN Triangulation of GRB 141215A (long/intense)
  17. GRB 141212A iTelescope observation
  18. GRB 141212A: Zadko observatory - Gingin optical observations
  19. GRB 141212B: MITSuME Akeno upper limits
  20. GRB 141212A: Swift/UVOT Upper Limits
  21. GRB 141212B: Swift/UVOT Upper Limits
  22. GRB 141212A: VLA upper limit
  23. GRB 141212A: Gemini-N spectroscopy and photometry
  24. GRB 141212B: Enhanced Swift-XRT position
  25. Swift detection of 4U 1700+24 (= V934 Her)
  26. GRB 141212A: MITSuME Okayama upper limits
  27. GRB 141212A: extended object within the XRT error circle
  28. GRB 141212A: Khureltogot optical upper limit
  29. GRB 141212A: 1.23m CAHA I-band observations
  30. GRB 141212B: initial Swift/UVOT observations
  31. GRB 141212A: Enhanced Swift-XRT position
  32. GRB 141212A: Skynet R-COP Observations
  33. GRB 141212A: MITSuME Akeno upper limits
  34. GRB 141212B: Swift detection of a burst
  35. GRB 141212A: Swift detection of a short burst
  36. GRB 141207A: Swift-XRT afterglow candidate detection
  37. GRB141202A: Discovery Channel Telescope Optical Observations
  38. GRB141207A: Discovery Channel Telescope Optical Observations
  39. GRB 141207A: Swift-XRT observations
  40. GRB141121A: Discovery Channel Telescope Optical Observations
  41. GRB 141205A: Swift/UVOT Upper Limits
  42. GRB 141205A: Nanshan optical upper limit
  43. GRB 141121A: Mondy optical observations
  44. GRB 141130A: Mondy optical observations
  45. GRB 141030A: Nanshan very early optical observations
  46. GRB 141121A: Continued RATIR Optical Observations
  47. GRB 141130A: Swift/UVOT Detection
  48. GRB 141130A: Enhanced Swift-XRT position
  49. GRB 141130A: Nanshan optical observations
  50. GRB 141130A: Mondy optical observations
  51. GRB 141130A: Swift detection of a burst with an optical counterpart
  52. GRB 141121A: Continued RATIR Optical Observations
  53. GRB 141121A: Mondy optical observations
  54. GRB 141121A: TSHAO optical observations
  55. GRB 141121A: Continued RATIR Optical Observations
  56. GRB 141121A: MITSuME Ishigakijima Optical Observation after 7 days
  57. GRB 141121A: Khureltogot optical observations
  58. GRB 141121A: Mondy optical observations
  59. GRB 141121A: RATIR Optical and NIR Observations
  60. IPN Triangulation of GRB 141125A (short/hard)
  61. GRB 141121A: three epochs of SAO RAS optical observations
  62. GRB 141121A: Continued RATIR Optical Observations
  63. GRB 141121A: TSHAO optical observations
  64. GRB 141121A: Continued Mondy optical observations
  65. GRB 141121A: Continued RATIR Optical Observations
  66. GRB 141121A: RATIR Optical Observations - Steeper Fading
  67. GRB 141121A: MITSuME Ishigakijima Optical Observation after 3 days
  68. GRB 141121A: RATIR Optical Observations - Fading Again
  69. GRB141124A: MASTER Detection of New Flare of QSO NVSS J075043+790917 During the Fermi Error Box inspection
  70. GRB 141121A: Mondy optical observations
  71. GRB 141121A: MITSuME Ishigakijima Optical Observation
  72. GRB 141121A: Continued RATIR Optical Observations - Rebrightening
  73. GRB 141121A: AAO optical observations
  74. GRB 141121A: MITSuME Akeno Optical observation
  75. GRB 141121A: Continued RATIR Optical Observations
  76. GRB 141121A: Swift/UVOT Detections
  77. GRB 141121A: RATIR Optical Observations
  78. GRB 141121A: Enhanced Swift-XRT position
  79. GRB 141118A: iPTF Optical Observations
  80. GRB 141121A: GROND Afterglow candidate
  81. GRB 141121A: Swift detection of a burst
  82. IPN Triangulation of GRB 141118A
  83. GRB 141104A: further Swift-XRT observations and afterglow candidate
  84. Swift Trigger 618673: probable noise event
  85. Trigger 618634: Swift detection of Vela X-1
  86. GRB 141109B: optical upper limits
  87. GRB 141015A: TAROT La Silla observatory optical observations
  88. GRB 141022A: TAROT La Silla observatory optical observations
  89. GRB 141031A: TAROT La Silla observatory optical observations
  90. GRB 141109A: TAROT La Silla observatory optical observations
  91. GRB 141109A: AAO optical observations
  92. Swift Trigger 618402: probable noise event
  93. GRB 141109A: Terskol photometry
  94. GRB 141109B: Swift/UVOT Upper Limits
  95. GRB 141109A: Swift/UVOT Detection
  96. GRB 141109A: NOT r-band observation
  97. GRB 141109B: MITSuME Akeno upper limits
  98. GRB 141109A: MITSuME Ishigakijima upper limits
  99. GRB 141109A: Swift-XRT refined Analysis
  100. GRB 141109B: Enhanced Swift-XRT position

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