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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"

19572 results found.

  1. GRB 180718A: Swift-XRT observations
  2. GRB 180720B: MASTER Global Net OT observations
  3. GRB 180720B: REM photometry
  4. GRB 180720B: ISON-Castelgrande optical observations
  5. GRB 180720B: COATLI Optical Detection
  6. GRB 180720C: BOOTES-2/TELMA optical observations
  7. GRB 180722A: Tiled Swift observations
  8. GRB 180721A: Swift/UVOT Upper Limits
  9. FRB 180714: MASTER optical inspection of the Fast Rado Burst Transient
  10. ANTARES neutrino Alert180713.02: MASTER optical observation
  11. GRB 180720B: Swift-BAT refined analysis
  12. GRB 180721A: Enhanced Swift-XRT position
  13. GRB 180721A: Swift detection of a burst
  14. GRB 180720C: Swift/UVOT Upper Limits
  15. GRB 180720C: Enhanced Swift-XRT position
  16. GRB 180720C: Swift detection of a burst or possible Galactic Transient
  17. GRB 180720B : TSHAO optical observations
  18. GRB 180715A: MASTER optical observation
  19. GRB 180720B: Kanata 1.5m optical/NIR observation
  20. GRB 180720B: Swift detection of a burst
  21. GRB 180715A: Gemini imaging upper limits
  22. GRB 180715A: Swift/UVOT Upper Limits
  23. Swift detects a flare from AX 1631.9-4752
  24. GRB 180718A: Swift ToO observations
  25. GRB 180718B: Swift ToO observations
  26. GRB 180715A: COATLI Optical Observations
  27. GRB 180715A: Swift-XRT observations
  28. GRB 180715A: GOTO optical limits
  29. GRB 180715A: LCO Sutherland possible optical candidate
  30. GRB 180715A: Swift-XRT observations
  31. IceCube-171106A: MASTER optical observation
  32. GRB 180705A: OSN observations
  33. GRB 180709A: Swift/UVOT Upper Limits
  34. GRB 180709A: Optical limits
  35. GRB 180709A: COATLI Optical Observations
  36. GRB 180709A: Enhanced Swift-XRT position
  37. GRB 180703A: Swift-XRT afterglow detection
  38. GRB 180709A: Swift detection of a burst
  39. GRB 180705A: RTT150 optical upper limit
  40. Trigger 846740: Swift trigger near NGC5055
  41. IPN Triangulation of GRB 180703A
  42. GRB 180706A: GOTO optical limits
  43. GRB 180706A: TSHAO optical observations
  44. GRB 180706A: Swift/UVOT Detection
  45. GRB 180706A: Enhanced Swift-XRT position
  46. GRB 180705A: TSHAO optical upper limit
  47. GRB 180705A: Swift/UVOT Upper Limits
  48. GRB 180705A: RATIR Optical Observations
  49. GRB 180706A: COATLI Optical Detection
  50. GRB 180706A: Swift detection of a burst with optical counterpart
  51. IPN Triangulation of GRB 180703B
  52. GRB 180705A: Enhanced Swift-XRT position
  53. GRB 180705A: Swift-XRT observations
  54. GRB 180703A: Swift/UVOT Upper Limits
  55. GRB 180704A: Swift/UVOT Upper Limits
  56. GRB 180704A: Enhanced Swift-XRT position
  57. GRB 180704A: Swift-XRT observations
  58. GRB 180704A: MASTER optical observation
  59. GRB 180703A: Tiled Swift observations
  60. GRB 180630A: Swift/UVOT Detection
  61. GRB 180630A: Fermi GBM detection
  62. GRB 180630A: Enhanced Swift-XRT position
  63. GRB 180630A: Swift detection of a burst with an optical counterpart
  64. GRB 180626A: TSHAO optical upper limit
  65. GRB 180626A: RATIR Optical Observations
  66. IPN Triangulation of GRB 180626C (short)
  67. IPN Triangulation of GRB 180626B (short)
  68. GRB 180626A: KAIT Optical Upper Limit
  69. GRB 180626A: COATLI Optical Detection
  70. GRB 180626A: Swift/UVOT Detection
  71. GRB 180626A: RATIR Optical Detection
  72. GRB 180626A: ISON-MN optical observations
  73. GRB 180626A: Enhanced Swift-XRT position
  74. GRB 180626A: Swift detection of a burst with an optical counterpart
  75. GRB 180624A: RATIR Optical Observations
  76. GRB 180624A: LBT/MODS redshift measurement
  77. GRB 180613A: LCO Afterglow detection
  78. GRB 180624A: GROND observations
  79. GRB 180624A: MITSuME Okayama optical upper limits
  80. GRB 180624A: Swift/UVOT Upper Limits
  81. GRB 180624A: Enhanced Swift-XRT position
  82. GRB 180624A: Swift detection of a burst
  83. GRB 180623A: Swift/UVOT Detection
  84. GRB 180623A: Enhanced Swift-XRT position
  85. GRB 180623A: Swift detection of a burst
  86. GRB 180620B: Swift/UVOT Detection
  87. GRB 180620A iTelescope observation
  88. GRB 180613A: Afterglow confirmation and added photometry
  89. GROND observations of GRB 180620B
  90. GROND observations of GRB 180620A
  91. GRB 180620B: Enhanced Swift-XRT position
  92. GRB 180620A: Xinglong-2.16m optical observations
  93. GRB 180618A: Swift/UVOT Detection
  94. GRB 180618A: TSHAO optical upper limit
  95. GRB 180620B: Swift detection of a burst with an optical counterpart
  96. GRB 180620A: COATLI Detection and Light Curve
  97. GRB 180620A: Swift/UVOT Detection
  98. GRB 180618A: Xinglong-2.16m optical upper limit
  99. GRB 180620A: Enhanced Swift-XRT position
  100. GRB 180620A: ISON-MN afterglow confirmation

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