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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"

8476 results found.

  1. Swift Trigger 639636: a possible GRB
  2. GRB 150428C: Tiled Swift observations
  3. GRB 150428A: GROND Dark Burst Host Candidate
  4. GRB 150428B: Swift detection of a burst
  5. GRB 150428A: Swift detection of a burst
  6. Trigger 639199: Swift detection of IGRJ16418-4532
  7. GRB 150424B: Tiled Swift observations
  8. GRB 150423A: WHT observations
  9. GRB 150424A: Swift detection of a short burst
  10. GRB 150423A: Keck optical afterglow confirmation
  11. GRB 150423A: GROND afterglow candidate
  12. GRB 150423A: Swift detection of a short burst
  13. Swift trigger 638589 is probably not an astrophysical source
  14. GRB 150418A: Tiled Swift observations
  15. Swift Trigger 638217 is probably not an astrophysical source
  16. GRB150413A, optical observations
  17. GRB 150407A: Swift ToO observations
  18. Swift triggered on a source in Terzan 5 (trigger=637212)
  19. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  20. GRB 150403A: Swift detection of a burst with an optical counterpart
  21. GRB 150402A: results of Swift observations
  22. GRB 150402A: Swift ToO observations
  23. GRB 150323C: possible host galaxy detection
  24. GRB 150220A: Optical observations at Kyiv comet station
  25. GRB 150323C: Swift detection of a burst
  26. GRB 150323B: Swift ToO observations
  27. GRB 150323A: P60 Optical Afterglow Candidate
  28. GRB 150323A: Swift detection of a burst
  29. GRB 150318A: Swift detection of a burst
  30. GRB 150317A: Swift detection of a burst
  31. GRB 150314A: KAIT Optical Candidate
  32. GRB 150222A: CrAO optical observation
  33. GRB150309A: Optical observations at Crni Vrh
  34. GRB 150309A: Swift detection of a burst
  35. Swift J0045.2+4151: analysis of XMM-Newton archival data
  36. GRB 150302A: Mondy optical upper limit
  37. GRB 150302A: Swift/UVOT Upper Limits
  38. GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
  39. GRB 150302A: KAIT Optical Upper Limit
  40. GRB 150302A: UVOT Observations
  41. GRB 150302A: NOT afterglow candidate
  42. GRB 150302A: Swift detection of a burst
  43. GRB 150301B: GROND afterglow observations
  44. GRB 150301B: Swift detection of a burst with an optical afterglow
  45. Swift Trigger 633173 is probably not an astrophysical source
  46. GRB 150301A: Fermi GBM observation
  47. GRB 150301A: Swift detection of a short burst or new SGR
  48. GRB 150220A: Swift ToO observations
  49. GRB 150222A: I-band observations from OSN
  50. GRB 150222A: GROND optical afterglow candidate
  51. GRB 150222A: Swift detection of a burst
  52. Swift detection of an outburst from SGR 1935+2154
  53. GRB 150219A: Swift ToO observations
  54. GRB 150213B: Swift detection of a burst with an optical afterglow
  55. GRB 150213A: Fermi GBM detection
  56. GRB 150212A: No Swift/UVOT detection in initial observation
  57. GRB 150212A: P60 Afterglow Retraction
  58. GRB150212A: P60 Afterglow Candidate
  59. GRB 150210A: Tiled Swift observations
  60. GRB 150211A: No afterglow detection in the Swift/UVOT initial observation
  61. GRB 150210A: Fermi GBM detection
  62. GRB 150206B: iPTF Optical Observations
  63. GRB 150206A: Swift detection of a burst with an optical afterglow
  64. GRB 150204A: Swift ToO observations
  65. GRB 150202B: Tiled Swift observations
  66. Swift Trigger 629693: probably not real
  67. GRB 150203A: Swift detection of a burst
  68. GRB 150202A: Swift detection of a burst
  69. GRB 150201A: Swift detection of a burst
  70. GRB 150123A: MASTER inspection
  71. Swift Trigger 628458 likely not astrophysical
  72. GRB 150126A: Fermi GBM Detection
  73. GRB 150126A: MAXI/GSC afterglow candidate detection
  74. GRB 150123A Tiled Swift observations
  75. GRB 150120B, Optical observations
  76. GRB 150101B: Confirmation of a fading optical counterpart
  77. GRB 150101B/Swift J123205.1-105602, deep VLT observations
  78. GRB 150120B: FTN optical afterglow confirmation
  79. GRB 150120B: Swift detection of a burst
  80. GRB 150120A: Swift detection of a possibly-short burst
  81. GRB 150101B/Swift J123205.1-105602: continued WSRT radio and VLT optical observations
  82. GRB 150110C Tiled Swift observations
  83. GRB 150110B: Swift detection of a burst
  84. GRB 150101B/Swift J123205.1-105602: WSRT radio observation
  85. GRB 150101B/Swift J123205.1-105602: VLT observations and redshift
  86. Swift J123205.1-105602: Magellan candidate afterglow
  87. GRB 150103A: Swift detection of a burst
  88. GRB 150101A: Swift detection of a short burst
  89. GRB 141230A: Fermi GBM detection
  90. GRB 141230A: Nanshan optical obsrvations
  91. GRB 141230A: iPTF Optical Observations and Candidate Afterglow iPTF14jko
  92. GRB 141229A: Fermi GBM detection
  93. GRB 141229A Tiled Swift observations
  94. GRB 141225A: Fermi GBM detection
  95. GRB 141225A: UVOT detection
  96. GRB 141225A: LT optical candidate
  97. GRB 141225A: Swift detection of a burst
  98. GRB141221A: REM afterglow
  99. GRB 141221A: Swift detection of a burst with an optical counterpart
  100. GRB 141121A: Keck observations

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