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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"
  1. GRB 151205B: Swift-XRT observations
  2. GRB 151205A: Swift/UVOT Upper Limits
  3. GRB 151205B: Swift detection of a burst
  4. GRB 151205A: Enhanced Swift-XRT position
  5. GRB 151205A: Swift detection of a burst
  6. GRB 151127A iTelescope observation
  7. LIGO/Virgo G184098: Results of of 2nd epoch of ASKAP follow-up
  8. Fermi GBM trigger 470712580/151202062 is not a GRB
  9. Fermi GBM trigger 470290196/151127174 is not a GRB
  10. GRB 151122A: Further Swift-XRT observations, no afterglow detected.
  11. Fermi GBM trigger 470375959/151128166 is not a GRB
  12. GRB 151127A: Swift/UVOT Upper Limits
  13. GRB 151127A: Swift-XRT refined Analysis
  14. GRB 151127A: Swift-BAT refined analysis
  15. GRB 151127A: Enhanced Swift-XRT position
  16. GRB151127A: Planned XMM-Newton observation
  17. GRB 151127A: GROND K-band upper limit
  18. GRB 151127A: LCOGT-SSO optical upper limits
  19. GRB 151127A: Swift detection of a short burst
  20. GRB 151118A iTelescope observation
  21. GRB 151122A: Swift/UVOT Observations
  22. GRB 151122A: Swift-XRT observations
  23. GRB 151122A: Fermi GBM detection
  24. GRB 151122A: Swift ToO observations
  25. Subject: GRB 151122A: Swift detection of a burst
  26. Konus-Wind observation of GRB 151120A
  27. GRB 151027A: Maidanak optical observations
  28. Swift-BAT refined analysis of trigger 664624 from SGR J1819-1600
  29. Swift Trigger 664610 is not astrophysical
  30. Swift-BAT probable detection of an outburst from SGR J1819-1600 (AX J1818.8-1559)
  31. Swift Trigger 664610: is unlikely a GRB
  32. GRB 151118A: MITSuME Akeno optical upper limits
  33. GRB 151120A: Swift-XRT afterglow detection
  34. GRB 151120A: Fermi GBM observation
  35. GRB 151118A: AAO optical upper limit
  36. LIGO/Virgo G194575: Updated significance from offline GW analysis
  37. GRB 151120A: Swift ToO observations
  38. GRB 151120A: GROND optical/NIR afterglow
  39. GRB 151120A: A long GRB detected by INTEGRAL
  40. GRB 151118A, Swift-BAT refined analysis
  41. LIGO/Virgo G194575: Fermi GBM Observations
  42. 610 MHz detection of GRB 151027A with the GMRT
  43. GRB 151118A: Early optical limit from pt5m, La Palma
  44. GRB 151118A: ISON-NM early optical limit
  45. GRB 151118A: Swift-XRT refined Analysis
  46. GRB 151027A: SAO RAS and Mt. Terskol observations
  47. GRB 151118A: Swift/UVOT Upper Limits
  48. GRB 151118A: Enhanced Swift-XRT position
  49. GRB GRB 151118A: MASTER-NET optical observations
  50. GRB 151118A: Optical observations from OSN
  51. GRB 151118A: Swift detection of a burst
  52. Swift-BAT resumption of normal operations
  53. GRB151027A; Optical observations
  54. GMRT radio detection of GRB 151027A
  55. GRB 151114A: GROND Detection of the Optical/NIR Afterglow Candidate
  56. GRB 151114A: Swift-XRT refined Analysis
  57. GRB 151107B: CALET Gamma-Ray Burst Monitor detection
  58. GRB 151114A: Swift-BAT refined analysis
  59. GRB 151112A: GROND photometric redshift and i'-band prediction
  60. GRB 151114A: Swift/UVOT Detection
  61. GRB 151114A: LCOGT-FTS afterglow observations
  62. GRB 151114A: Enhanced Swift-XRT position
  63. GRB 151114A: Swift detection of a burst with an optical counterpart
  64. GRB 151111A: GROND confirmation of the afterglow and photometric redshift estimate
  65. GRB 151112A: Swift/UVOT Upper Limits
  66. GRB 151112A: MAXI/GSC detection
  67. GRB 151112A: GROND Detection of the Optical/NIR Afterglow Candidate
  68. GRB 151112A: Swift-XRT refined Analysis
  69. GRB 151112A: Swift-BAT refined analysis
  70. GRB 151112A: Enhanced Swift-XRT position
  71. GRB 151112A: MASTER-NET optical limit
  72. GRB 151112A: initial UVOT observations
  73. GRB 151112A: Swift-XRT observations
  74. GRB 151112A: Swift detection of a burst
  75. GRB 151111A: Swift/UVOT upper limits
  76. Swift-BAT trigger 663164 is not a burst.
  77. GRB 151111A: GROND marginal detection of a afterglow candidate
  78. LIGO/Virgo G194575: VLA follow-up
  79. GRB 151111A: Swift-XRT refined Analysis
  80. GRB 151111A: Fermi GBM observation
  81. GRB 151111A: LCOGT-FTS afterglow observations
  82. GRB 151111A: Swift-BAT refined analysis
  83. GRB 151111A: Enhanced Swift-XRT position
  84. GRB 151111A: Swift detection of a burst
  85. IPN triangulation of GRB151107B
  86. GRB 151107B: MASTER-NET OT detection inside the FERMI error box
  87. GRB 151027A: continued Mondy optical observations
  88. GRB 151107B: Mini-MegaTORTORA limits on simultaneous optical emission
  89. LIGO/Virgo G194575: Liverpool Telescope observations of iPTF-15dld and iPTF-15dni
  90. LIGO/Virgo G194575: La Silla QUEST, Pan-STARRS and PESSTO observations of iPTF15dld
  91. GRB 151107A: Further investigation of the source nature
  92. GRB 151107B
  93. LIGO/Virgo G194575: Swift observations if iPTF15dld
  94. GRB 151107A, Swift-BAT refined analysis
  95. GRB 151027A: Hankasalmi optical observations
  96. LIGO/Virgo G194575: INAF-TNG/Asiago Telescope follow-up of iPTF15dld
  97. GRB 151107A: MASTER-NET optical observations
  98. GRB 151107A: Swift detection of a possible burst
  99. LIGO/Virgo G194575: INAF-Asiago Telescope further analysis of iPTF candidates
  100. Swift-BAT triggers are disabled

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