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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"

42591 results found.

  1. GRB 130420A: Enhanced Swift-XRT position
  2. GRB130420A : Xinglong TNT optical upper limit
  3. GRB 130420B: Faulkes Telescope North observations
  4. GRB 130420B: MASTER-Net optical observations
  5. GRB 130420B: Swift detection of a burst
  6. GRB 130420A: T21 optical observations
  7. GRB 130420A: RATIR Optical and NIR Observations
  8. GRB 130420A: PAIRITEL NIR detections
  9. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  10. GRB 130420A: Swift detection of a burst with an optical counterpart
  11. GRB 130420A: Faulkes Telescope North candidate
  12. GRB 130418A: Continued RATIR Optical and NIR Observations
  13. GRB 130418A: Swift-XRT refined Analysis
  14. Swift Trigger 553930 is not an astrophysical source
  15. GRB 130418A: SMARTS optical/IR afterglow observations
  16. GRB 130418A: Submm observations from SMA
  17. GRB 130419A, Swift-BAT refined analysis
  18. GRB 130327B: Swift/XRT source is not the afterglow
  19. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  20. Trigger 553930: Swift detection of a possible flare from HR 5110
  21. GRB 130418A: T21 optical observation
  22. GRB 130418A: T18 and T21 optical observations
  23. GRB 130418A: LOAO Observation
  24. GRB 130418A, Swift-BAT refined analysis
  25. GRB 130419A: Swift detection of a burst
  26. GRB130418A: VLT/X-shooter redshift confirmation
  27. GRB 130418A: RATIR Optical and NIR Observations
  28. GRB 130418A: CARMA 3mm detection
  29. GRB 130418A: GROND detection of the optical-NIR afterglow
  30. GRB130418A: OSN 1.5m fading afterglow detection
  31. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  32. GRB 130418A: Enhanced Swift-XRT position
  33. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  34. GRB 130418A: TNG optical observations
  35. GRB 130418A: Redshift from 10.4m GTC
  36. GRB 130418A: Bassano Bresciano Observatory optical observations
  37. GRB 130418A: 1.23m I-band observations
  38. GRB 130418A: Swift detection of a burst with an optical counterpart
  39. GRB 130408A: Suzaku WAM observation of the prompt emission
  40. GRB 130408a: Skynet Optical Observations
  41. GRB 130408A: SMARTS optical/IR afterglow observations
  42. GRB 130408A, Swift-BAT refined analysis
  43. GRB 130408A: Zadko observatory - Gingin optical observations
  44. GRB 130407A: Swift-XRT observations
  45. GRB130408A: Swift/UVOT followup observations
  46. GRB 130408A: Swift-XRT refined Analysis
  47. Konus-Wind observation of GRB 130408A
  48. GRB 130408A: Enhanced Swift-XRT position
  49. GRB 130408A - Gemini-S/GMOS redshift determination
  50. GRB 130408A - VLT/X-shooter redshift determination
  51. GRB 130408A: GROND detection of the afterglow
  52. GRB 130408A: Swift/UVOT Detection of the Optical Afterglow
  53. GRB 130408A: Liverpool Telescope Optical candidate detection
  54. GRB 130408A: Swift detection of a burst
  55. GRB 130407A Tiled Swift observations
  56. GRB 130407A: MAXI/GSC detection
  57. GRB 130211A: Retraction of afterglow candidate
  58. GRB 130327B: Suzaku WAM observation of the prompt emission
  59. Konus-Wind observation of GRB 130320B
  60. Swift detection of IGR J18245-2452
  61. IPN Triangulation of GRB 130320B (very long/bright)
  62. Swift/XRT observation of GRB 130327B
  63. GRB 130327A: RATIR Optical/NIR afterglow confirmation
  64. GRB 130306A: Confirmation of the X-ray Afterglow
  65. GRB 130310A: RATIR Observations
  66. Swift Trigger 552142 is a noise event
  67. Konus-Wind observation of GRB 130327B
  68. GRB 130327B: Fermi-LAT detection of a burst
  69. GRB 130327B: Fermi GBM detection
  70. Swift Trigger 552142: a possible GRB
  71. GRB 130327B: gamma-ray detection by AGILE
  72. GRB 130327A: Swift-BAT refined analysis
  73. GRB 130327A: Gemini Observations
  74. GRB 130327A: Swift-XRT refined Analysis
  75. GRB 130327A: Weihai optical obsevations
  76. GRB 130327A: Swift/UVOT Upper Limits
  77. Konus-Wind observation of GRB 130325A
  78. GRB 130327A: ISON-NM optical upper limit
  79. GRB 130325A Tiled Swift observations
  80. GRB 130327A: Enhanced Swift-XRT position
  81. GRB 130327A: RATIR Optical and NIR Observations
  82. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  83. GRB 130325A: Fermi LAT detection
  84. GRB 130327A: Swift detection of a burst
  85. report: GRB 130315A: Zadko observatory - Gingin optical observations
  86. GRB 130325A: Fermi GBM detection
  87. Konus-Wind observation of GRB 130320A
  88. IPN Triangulation of GRB 130320A (long/very bright)
  89. GRB 130305A: Gemini follow-up observations
  90. GRB 130315A: GROND afterglow candidate
  91. GRB 130305A: optical upper limit in Mondy observatory
  92. GRB 130315A: Swift/UVOT Upper Limits
  93. GRB 130313A: optical upper limit in CrAO
  94. GRB 130313A: optical upper limit in Mondy observatory
  95. GRB 130315A: SALT optical observations
  96. GRB130313A: GTC early optical limits
  97. GRB 130313A: 5.8 GHz VLA upper limit
  98. GRB 130315A: Swift-XRT refined Analysis
  99. Swift XRT observations of GRB 130310A
  100. GRB 130315A, Swift-BAT refined analysis

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