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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"

7420 results found.

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

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