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

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