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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. Reactivation of SGR 1627-41
  2. GRB 080524: Swift XRT and UVOT analysis
  3. GRB 080503: 2nd Epoch Chandra X-ray Observations
  4. GRB 080524: Swift-BAT detection of a burst in ground analysis
  5. GRB 080523: Swift-XRT refined analysis
  6. GRB 080523, Swift-BAT refined analysis
  7. GRB 080520: VLT host detection
  8. GRB 080523: VLT optical observations
  9. Swift/UVOT observations of GRB 080523
  10. GRB 080523: Enhanced Swift-XRT position
  11. GRB 080523: Swift detection of a burst
  12. GRB 080515: NIR magnitude correction
  13. GRB 080515: KPNO 4m NIR afterglow detection
  14. GRB080521(?): detection of possible burst from BAT slew data and XRT ToO
  15. GRB 80516: Swift/UVOT Observations
  16. GRB 080515: Swift-XRT position and analysis
  17. GRB 080520, Swift-BAT refined analysis
  18. GRB 080514B: pseudo-z= 1.8 from prompt emission spectrum
  19. GRB 080514B: UVOT Observations
  20. GRB080520: Swift/UVOT observations
  21. GRB 080520: VLT redshift
  22. GRB 080520, GROND observations
  23. GRB 080520: Enhanced Swift-XRT position
  24. GRB 080520: Swift XRT Refined Analysis
  25. GRB 080520: Swift detection of a burst with optical afterglow
  26. GRB 080514B: Suzaku WAM observation of the prompt emission
  27. Konus-Wind observation of GRB 080514B
  28. GRB 080514B: second epoch Swift XRT data confirms the X-ray afterglow
  29. GRB 080503: Further HST imaging
  30. GRB 080517, Swift-BAT refined analysis
  31. GRB 080516, GROND further analysis
  32. GRB 080517: Swift-XRT refined analysis
  33. GRB 080514B: Further NIR observations
  34. GRB 080517: Enhanced Swift-XRT position
  35. GRB080517: Liverpool Telescope Optical Observations
  36. GRB 080517: Swift detection of a burst
  37. GRB 080516, GROND 2nd epoch observations
  38. GRB 080516, GROND observations
  39. GRB080430: optical observations
  40. GRB 080516, SMARTS optical/IR observations
  41. GRB 080516: Swift-XRT Team refined analysis
  42. GRB 080516, Swift-BAT refined analysis
  43. GRB 080516: Enhanced Swift-XRT position
  44. GRB 080514B: NOT observations
  45. GRB 080516: Swift detection of a burst
  46. Errartum: VLA upper limit on GRB 080507
  47. VLA upper limit on GRB 080705
  48. GRB 080514B : redshift estimation
  49. Konus-Wind observation of GRB 080513
  50. IPN triangulation of bright GRB 080513
  51. Swift-BAT refined analysis for Trigger 311603: Galactic source
  52. GRB 080515, Swift-BAT refined analysis
  53. GRB 080514B: KPNO 4m IR observations
  54. GRB 080514B: slow fading behaviour ?
  55. GRB 080514B: Swift-XRT analysis
  56. GRB 080514B, GROND observations
  57. GRB 080515: Swift detection of a burst
  58. GRB 080514B: Finding chart
  59. GRB 080514B: Afterglow candidate
  60. GRB 080514B: Watcher observations
  61. GRB 080430
  62. GRB 080514B: possible AGILE detection at E>50 MeV
  63. GRB 080514B: SuperAGILE/IPN GRB Localization
  64. procesure for GRB Circular
  65. Swift detection of a possible galactic transient
  66. GRB080514: REM NIR & Optical Observations
  67. Konus-Wind observation of GRB 080507
  68. GRB 080319B: Further HST observations and underlying host
  69. GRB 080506: NAYUTA Optical Observation
  70. GRB 080507: Suzaku WAM observation of the prompt emission
  71. GRB 080507: Swift XRT analysis confirms the X-ray afterglow
  72. GRB 080507: Keck photometry
  73. GRB 080507: E Pur Si Muove!
  74. GRB 080503: Chandra Observation of X-ray Rebrightening or Flattening
  75. GRB 080503: Hubble Space Telescope Imaging
  76. GRB080507: Swift/UVOT followup observations
  77. GRB 080507: Optical Afterglow
  78. GRB 080506:Optical observations from HCT
  79. GRB 080507: Swift-XRT position of a possible afterglow
  80. GRB 080506: VLA radio upper limit
  81. GRB 080507: GRB localization by SuperAGILE
  82. GRB 080506: TLS 2nd Epoch - possible light curve break
  83. GRB 080503: Fading in continued Gemini imaging
  84. GRB 080506: Swift XRT refined analysis
  85. GRB080506: Swift/UVOT observations
  86. GRB 080506, Swift-BAT refined analysis
  87. GRB080503, RIMOTS optical upper limit
  88. GRB 080506: Observations from NOT
  89. GRB 080506: optical observation from Ondrejov
  90. GRB 080506: TLS afterglow detection in VRIZ
  91. GRB 080506: Enhanced Swift-XRT position
  92. GRB 080506: Optical observation with KANATA/TRISPEC
  93. GRB 080506: Swift detection of a burst with optical afterglow
  94. GRB 080503: VLA radio upper limit
  95. GRB 080503: Observations from NOT
  96. GRB 080503: Slow-rise optical AG ?
  97. GRB 080430: TLS imaging one day after the GRB
  98. GRB 080503: No further optical rebrightening
  99. GRB 080503: Late-time Optical rebrightening (possible mini-SN) - correction
  100. GRB 080503: Late-time Optical rebrightening (possible mini-SN)

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