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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 080520: Swift detection of a burst with optical afterglow
  2. GRB 080514B: Suzaku WAM observation of the prompt emission
  3. Konus-Wind observation of GRB 080514B
  4. GRB 080514B: second epoch Swift XRT data confirms the X-ray afterglow
  5. GRB 080503: Further HST imaging
  6. GRB 080517, Swift-BAT refined analysis
  7. GRB 080516, GROND further analysis
  8. GRB 080517: Swift-XRT refined analysis
  9. GRB 080514B: Further NIR observations
  10. GRB 080517: Enhanced Swift-XRT position
  11. GRB080517: Liverpool Telescope Optical Observations
  12. GRB 080517: Swift detection of a burst
  13. GRB 080516, GROND 2nd epoch observations
  14. GRB 080516, GROND observations
  15. GRB080430: optical observations
  16. GRB 080516, SMARTS optical/IR observations
  17. GRB 080516: Swift-XRT Team refined analysis
  18. GRB 080516, Swift-BAT refined analysis
  19. GRB 080516: Enhanced Swift-XRT position
  20. GRB 080514B: NOT observations
  21. GRB 080516: Swift detection of a burst
  22. Errartum: VLA upper limit on GRB 080507
  23. VLA upper limit on GRB 080705
  24. GRB 080514B : redshift estimation
  25. Konus-Wind observation of GRB 080513
  26. IPN triangulation of bright GRB 080513
  27. Swift-BAT refined analysis for Trigger 311603: Galactic source
  28. GRB 080515, Swift-BAT refined analysis
  29. GRB 080514B: KPNO 4m IR observations
  30. GRB 080514B: slow fading behaviour ?
  31. GRB 080514B: Swift-XRT analysis
  32. GRB 080514B, GROND observations
  33. GRB 080515: Swift detection of a burst
  34. GRB 080514B: Finding chart
  35. GRB 080514B: Afterglow candidate
  36. GRB 080514B: Watcher observations
  37. GRB 080430
  38. GRB 080514B: possible AGILE detection at E>50 MeV
  39. GRB 080514B: SuperAGILE/IPN GRB Localization
  40. procesure for GRB Circular
  41. Swift detection of a possible galactic transient
  42. GRB080514: REM NIR & Optical Observations
  43. Konus-Wind observation of GRB 080507
  44. GRB 080319B: Further HST observations and underlying host
  45. GRB 080506: NAYUTA Optical Observation
  46. GRB 080507: Suzaku WAM observation of the prompt emission
  47. GRB 080507: Swift XRT analysis confirms the X-ray afterglow
  48. GRB 080507: Keck photometry
  49. GRB 080507: E Pur Si Muove!
  50. GRB 080503: Chandra Observation of X-ray Rebrightening or Flattening
  51. GRB 080503: Hubble Space Telescope Imaging
  52. GRB080507: Swift/UVOT followup observations
  53. GRB 080507: Optical Afterglow
  54. GRB 080506:Optical observations from HCT
  55. GRB 080507: Swift-XRT position of a possible afterglow
  56. GRB 080506: VLA radio upper limit
  57. GRB 080507: GRB localization by SuperAGILE
  58. GRB 080506: TLS 2nd Epoch - possible light curve break
  59. GRB 080503: Fading in continued Gemini imaging
  60. GRB 080506: Swift XRT refined analysis
  61. GRB080506: Swift/UVOT observations
  62. GRB 080506, Swift-BAT refined analysis
  63. GRB080503, RIMOTS optical upper limit
  64. GRB 080506: Observations from NOT
  65. GRB 080506: optical observation from Ondrejov
  66. GRB 080506: TLS afterglow detection in VRIZ
  67. GRB 080506: Enhanced Swift-XRT position
  68. GRB 080506: Optical observation with KANATA/TRISPEC
  69. GRB 080506: Swift detection of a burst with optical afterglow
  70. GRB 080503: VLA radio upper limit
  71. GRB 080503: Observations from NOT
  72. GRB 080503: Slow-rise optical AG ?
  73. GRB 080430: TLS imaging one day after the GRB
  74. GRB 080503: No further optical rebrightening
  75. GRB 080503: Late-time Optical rebrightening (possible mini-SN) - correction
  76. GRB 080503: Late-time Optical rebrightening (possible mini-SN)
  77. GRB 080503, Swift-BAT lag and time-resolved spectral analysis
  78. GRB 080503: MITSuME Ishigakijima optical upper limits
  79. GRB080503: Swift/UVOT Upper Limits
  80. GRB080503 XRT refined analysis
  81. GRB 080503, Swift-BAT refined analysis
  82. GRB 080430
  83. GRB 080430
  84. GRB 080430
  85. GRB 080503: Enhanced Swift-XRT position
  86. GRB 080503: MITSuME Akeno optical upper limits
  87. GRB 080503: New candidate afterglow/host in Gemini imaging
  88. GRB 080503: Optical afterglow candidate and LRIS spectroscopy of the short burst
  89. GRB 080503: Swift detection of a short burst
  90. GRB 080411: Continued Swift Monitoring
  91. GRB 080430: Optical observations
  92. GRB 080430: Shallow decay
  93. GRB080430: RTT150 Optical Observations
  94. GRB080430: Swift/UVOT observations
  95. VLA radio upper limit on GRB 080430
  96. GRB 080430 - multicolor observations of the afterglow
  97. GRB 080430 optical observations
  98. GRB 080430, Swift-BAT refined analysis
  99. GRB080430: optical observations
  100. GRB 080430: Hobby-Eberly Telescope Absorption Redshift

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