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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"

7422 results found.

  1. GRB 150120B: Swift detection of a burst
  2. GRB 150120A: Swift detection of a possibly-short burst
  3. The Swift Detection of a Large Flare from the RS CVn Binary SZ Psc
  4. GRB 150110C Tiled Swift observations
  5. GRB 150110B: Swift detection of a burst
  6. GRB 150101B/Swift J123205.1-105602: VLT observations and redshift
  7. Swift J123205.1-105602: Magellan candidate afterglow
  8. GRB 150103A: Swift detection of a burst
  9. GRB 150101A: Swift detection of a short burst
  10. GRB 141230A: Nanshan optical obsrvations
  11. GRB 141230A: iPTF Optical Observations and Candidate Afterglow iPTF14jko
  12. GRB 141229A Tiled Swift observations
  13. GRB 141225A: UVOT detection
  14. GRB 141225A: LT optical candidate
  15. GRB 141225A: Swift detection of a burst
  16. GRB141221A: REM afterglow
  17. GRB 141221A: Swift detection of a burst with an optical counterpart
  18. GRB 141215A Tiled Swift observations
  19. Swift detection of 4U 1700+24 (= V934 Her)
  20. GRB 141212B: initial Swift/UVOT observations
  21. GRB 141212A: Swift detection of a short burst
  22. GRB 141207A: Swift-XRT afterglow candidate detection
  23. GRB 141207A Tiled Swift observations
  24. GRB 141202A Tiled Swift observations
  25. GRB 141121A: Continued RATIR Optical Observations
  26. GRB 141130A: Mondy optical observations
  27. GRB 141130A: Swift detection of a burst with an optical counterpart
  28. GRB 141124A​: iPTF upper limits​
  29. GRB 141118A: Fermi GBM Detection
  30. GRB 141118A: iPTF Optical Observations
  31. GRB 141121A: GROND Afterglow candidate
  32. GRB 141121A: Swift detection of a burst
  33. GRB 141104A: further Swift-XRT observations and afterglow candidate
  34. Swift Trigger 618673: probable noise event
  35. Swift Trigger 618402: probable noise event
  36. GRB 141109A: REM NIR candidate afterglow
  37. GRB 141109B: Swift detection of a burst
  38. GRB 141109A: Swift detection of a burst
  39. GRB 141104A: Swift-XRT observations
  40. GRB 141104A Tiled Swift observations
  41. GRB 141031B: Swift detection of a burst
  42. GRB 141031A: GROND detection of a possible optical afterglow candidate
  43. GRB 141031A: Swift detection of a burst
  44. GRB 141029A Tiled Swift observations
  45. GRB 141028A: Swift/XRT detection of the X-ray afterglow
  46. GRB 141028A: GROND Afterglow confirmation (MASTER source)
  47. GRB 141028A Tiled Swift observations
  48. GRB 141028A: MASTER OT candidate detection
  49. GRB 141026A: GROND observations
  50. GRB 141026A: Swift detection of a burst
  51. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  52. GRB 141022A: Swift detection of a burst
  53. GRB 141020A: Swift detection of a burst with an optical counterpart
  54. GRB 141017A: Swift detection of a burst
  55. GRB 141015A: Swift/XRT localization
  56. GRB 141005A: Additional P60 imaging and afterglow confirmation
  57. GRB 141005A: Swift detection of a burst
  58. GRB 141004A: Swift detection of a burst with an optical counterpart
  59. Swift observations of HD 305560
  60. GRB 140930B: GROND observations
  61. GRB 140930B: MMT confirmation of the optical afterglow
  62. GRB 140930B: ISON-Kislovodsk observations
  63. GRB 140930B: WHT detection of candidate afterglow
  64. GRB 140930B: Swift detection of a short burst
  65. GRB 140930A/MAXI J2259+524: MAXI-GSC detection
  66. GRB 140928A: GROND Afterglow Candidate
  67. GRB 140927A: Swift detection of a burst
  68. GRB 140919A: GROND afterglow candidate
  69. GRB 140919A: Swift/UVOT observations
  70. GRB 140916B: iPTF Optical Observations
  71. GRB 140916A: Swift detection of a burst
  72. GRB 140903A: Chandra detection of the afterglow
  73. GRB140907A: Swift UVOT detection
  74. GRB 140906A: iPTF optical transient candidates
  75. GRB 140903A: Confirmation of Optical Fading from Discovery Channel Telescope
  76. GRB 140903A: tentative spectroscopic redshift
  77. GRB140903A: Discovery Channel Telescope Optical Detection
  78. GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
  79. GRB 140829A: iPTF optical observations
  80. GRB 140824B: Swift observations
  81. GRB 140824A: Swift detection of a burst
  82. GRB 140817A: Khureltogot optical upper limit
  83. GRB 140818B: ISON-Kislovodsk and ISON-Burakan optical upper limit
  84. GRB 140818A: GROND confirmation of afterglow candidate
  85. GRB140819A: Deep GROND Upper Limits
  86. Fermi 430148973/MASTER candidate: LCO-Sutherland observations
  87. Fermi trigg_num 430148973: OSN I-band observations
  88. GRB 140818B : Correction to GCN 16713
  89. GRB 140818B: Swift/UVOT Upper Limits
  90. GRB140818B : GROND afterglow candidate
  91. GRB 140818B: OSN I-band afterglow candidate
  92. GRB 140818B: Swift detection of a burst
  93. Swift detection of SAX J1712.6-3739
  94. GRB 140818A Tiled Swift observations
  95. GRB 140817A: Swift detection of a burst
  96. GRB 140808A / PTFeag: VLA K-band observations
  97. GRB 140815A: GROND afterglow candidate
  98. Swift Trigger 609694 is probably not an astrophysical source
  99. Swift trigger 609139 is probably 4U 1850-03
  100. Swift observations of possible GRB 140809A candidate

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