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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"

7421 results found.

  1. GRB 151212A: GROND Optical Afterglow Candidate
  2. GRB 151212A: Tiled Swift observations
  3. GRB 151210A: Optical afterglow candidate from LCOGT-Cerro Tololo
  4. GRB 151210A: Swift detection of a burst
  5. GRB 151205C: Tiled Swift observations
  6. GRB151205B: Initial UVOT observations
  7. GRB 151205A: Swift detection of a burst
  8. GRB 151127A: Swift detection of a short burst
  9. GRB 151122A: Swift ToO observations
  10. Swift Trigger 664610: is unlikely a GRB
  11. LIGO/Virgo G194575: Updated significance from offline GW analysis
  12. GRB 151120A: Swift ToO observations
  13. LIGO/Virgo G194575: Fermi GBM Observations
  14. GRB 151118A: Swift detection of a burst
  15. GRB 151114A: GROND Detection of the Optical/NIR Afterglow Candidate
  16. GRB 151114A: Swift detection of a burst with an optical counterpart
  17. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  18. GRB 151112A: initial UVOT observations
  19. GRB 151111A: GROND marginal detection of a afterglow candidate
  20. GRB 151111A: LCOGT-FTS afterglow observations
  21. GRB 151111A: Swift detection of a burst
  22. GRB 151107A: Further investigation of the source nature
  23. LIGO/Virgo G194575: MAXI/GSC further analysis
  24. GRB 151027A: the missing GeV component
  25. LIGO/Virgo G194575: LT Spectroscopy of iPTF-15dmk
  26. GRB 151031A: Swift detection of a burst
  27. GRB 151029A: Swift detection of a burst with an optical counterpart
  28. GRB 151027B: NOT optical afterglow candidate
  29. LIGO/Virgo G194575 : RATIR Observation of La Silla - QUEST Candidate
  30. GRB 151027B: Swift detection of its 1000-th burst
  31. LIGO/Virgo G194575: iPTF Optical Transient Candidates
  32. GRB 151027A: Swift detection of a burst with a bright optical afterglow
  33. LIGO/Virgo G194575: MAXI/GSC observations
  34. Possible Fermi-LAT Gamma-ray counterpart for LIGO/Virgo G194575
  35. GRB 151023A: Swift detection of a burst
  36. LIGO/Virgo G194575: Fermi GBM Observations
  37. LIGO/Virgo G194575: transients from Pan-STARRS in the RA=1hr localisation region
  38. LIGO/Virgo G194575: Identification of a GW CBC Candidate
  39. GRB 151022A: Swift detection of a burst
  40. GRB 151021A: Swift detection of a burst
  41. GRB 151004A: Swift-XRT follow-up observations
  42. GRB 151006A: Swift detection of a burst
  43. LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
  44. LIGO/Virgo G184098: Ongoing gravitational-wave analysis
  45. GRB 151001B: Swift detection of a burst
  46. GRB 151001A: Swift detection of a burst with an optical counterpart
  47. LIGO/Virgo G184098: spectral classification of PS15cci
  48. GRB 150925A: Swift detection of a burst
  49. LIGO/Virgo G184098: TAROT network optical observations
  50. LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
  51. LIGO/Virgo G184098: iPTF Optical Transient Candidates
  52. LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
  53. LIGO/Virgo G184098: Burst candidate in LIGO engineering run data
  54. GRB 150915A: GROND detection of an optical counterpart candidate
  55. GRB 150915A: Swift detection of a burst
  56. GRB 150912A: Swift ToO observations
  57. GRB 150911A: Swift detection of a burst
  58. GRB 150910A: Swift detection of a burst with an optical afterglow
  59. Short GRB 150906B: proximity to NGC 3313 galaxy group
  60. GRB 150907A: Tiled Swift observations
  61. ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
  62. ANTARES neutrino detection: Optical/NIR spectroscopy of the Swift/XRT counterpart candidate from NOT
  63. GRB 150902A: Swift ToO observations
  64. GRB 150831A: Swift detection of a short burst
  65. GRB 150821A: Swift detection of a burst with an optical afterglow
  66. GRB 150819A: Swift detection of a burst
  67. GRB 150818A: Swift/UVOT candidate afterglow
  68. GRB 150817A: P60 Observations
  69. GRB 150818A: Swift detection of a burst
  70. GRB 150817A: Continued RATIR Observations, Revised Candidate
  71. GRB 150817A: RATIR Optical Afterglow Candidate
  72. Swift Trigger 652046 is probably not a GRB
  73. GRB 150811A: KAIT optical candidate
  74. GRB 150811A: Swift detection of a burst
  75. Fermi GBM GRB Trigger 460608875: iPTF P48 Observations
  76. Fermi GBM GRB Trigger 458852670: iPTF P48 Observations
  77. GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
  78. GRB 150801B: Swift detection of a burst
  79. GRB 150801A: Tiled Swift observations
  80. GRB 150728A: TSHAO optical observations
  81. GRB 150728A: Swift detection of a GRB
  82. GRB 150727A: Watcher optical upper limit
  83. GRB 150727A: Swift detection of a burst with an optical counterpart
  84. GRB 150724B: Swift ToO observations
  85. Trigger 650221: Swift detection of a IGR J00291+5934
  86. GRB 150724A: Swift detection of a burst
  87. Swift Trigger 649706: a possible GRB or bright Galactic transient
  88. GRB 150716A: P60 Candidate Optical Afterglow
  89. GRB 150716A: RATIR Optical Observations
  90. GRB 150716A: Swift detection of a burst
  91. Trigger 649113: Swift detection of SGR 1E 1841-045
  92. GRB 150711A: Swift detection of a burst
  93. GRB 150710B: Swift ToO observations
  94. MASTER OT Detection during Fermi Trigger 458235025 inspection
  95. GRB 150710A: host galaxy for Swift XRT second candidate
  96. Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
  97. GRB 150702A: Swift ToO observations
  98. Swift Trigger 647642 is probably not an astrophysical source
  99. GRB 150627A: Swift ToO observations
  100. GRB 150626B: Swift detection of a burst

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