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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: Hubble Space Telescope Imaging
  2. GRB080507: Swift/UVOT followup observations
  3. GRB 080507: Optical Afterglow
  4. GRB 080506:Optical observations from HCT
  5. GRB 080507: Swift-XRT position of a possible afterglow
  6. GRB 080506: VLA radio upper limit
  7. GRB 080507: GRB localization by SuperAGILE
  8. GRB 080506: TLS 2nd Epoch - possible light curve break
  9. GRB 080503: Fading in continued Gemini imaging
  10. GRB 080506: Swift XRT refined analysis
  11. GRB080506: Swift/UVOT observations
  12. GRB 080506, Swift-BAT refined analysis
  13. GRB080503, RIMOTS optical upper limit
  14. GRB 080506: Observations from NOT
  15. GRB 080506: optical observation from Ondrejov
  16. GRB 080506: TLS afterglow detection in VRIZ
  17. GRB 080506: Enhanced Swift-XRT position
  18. GRB 080506: Optical observation with KANATA/TRISPEC
  19. GRB 080506: Swift detection of a burst with optical afterglow
  20. GRB 080503: VLA radio upper limit
  21. GRB 080503: Observations from NOT
  22. GRB 080503: Slow-rise optical AG ?
  23. GRB 080430: TLS imaging one day after the GRB
  24. GRB 080503: No further optical rebrightening
  25. GRB 080503: Late-time Optical rebrightening (possible mini-SN) - correction
  26. GRB 080503: Late-time Optical rebrightening (possible mini-SN)
  27. GRB 080503, Swift-BAT lag and time-resolved spectral analysis
  28. GRB 080503: MITSuME Ishigakijima optical upper limits
  29. GRB080503: Swift/UVOT Upper Limits
  30. GRB080503 XRT refined analysis
  31. GRB 080503, Swift-BAT refined analysis
  32. GRB 080430
  33. GRB 080430
  34. GRB 080430
  35. GRB 080503: Enhanced Swift-XRT position
  36. GRB 080503: MITSuME Akeno optical upper limits
  37. GRB 080503: New candidate afterglow/host in Gemini imaging
  38. GRB 080503: Optical afterglow candidate and LRIS spectroscopy of the short burst
  39. GRB 080503: Swift detection of a short burst
  40. GRB 080411: Continued Swift Monitoring
  41. GRB 080430: Optical observations
  42. GRB 080430: Shallow decay
  43. GRB080430: RTT150 Optical Observations
  44. GRB080430: Swift/UVOT observations
  45. VLA radio upper limit on GRB 080430
  46. GRB 080430 - multicolor observations of the afterglow
  47. GRB 080430 optical observations
  48. GRB 080430, Swift-BAT refined analysis
  49. GRB080430: optical observations
  50. GRB 080430: Hobby-Eberly Telescope Absorption Redshift
  51. GRB 080430: Swift-XRT refined analysis
  52. GRB 080430: Enhanced Swift-XRT position
  53. GRB080430: Optical observation in AsU CAS Ondrejov & Brno
  54. GRB 080430: Spectroscopy from CAHA
  55. GRB 080430 - SDSS Pre-Burst Observations
  56. GRB 080430: Bootes observation
  57. GRB 080430: Swift detection of a burst with optical afterglow
  58. GRB 080430: TAROT Calern observatory optical observations
  59. GRB960202B - on the association with SN 1996cr
  60. GRB080426: Observations from CAHA
  61. GRB 080426: Swift-XRT refined analysis
  62. GRB080426: Swift/UVOT upper limits
  63. GRB 080426: Enhanced Swift-XRT position
  64. GRB 080426, Swift-BAT refined analysis
  65. GRB 080426: Swift detection of a possibly short burst
  66. Possible GRB 080315: XRT non-detection of afterglow
  67. GRB 080320 : Faulkes Telescope North Observations
  68. GRB 080319A : Liverpool and Faulkes Telescopes Observations
  69. GRB080319A: MAGIC telescope GeV observation
  70. Swift-BAT trigger 309665 is not a GRB
  71. GRB 080420A: ROTSE-III Optical Limits on a possible short burst
  72. GRB 080420?: Swift detection of a possible short burst
  73. GRB080310, BVRcIc field calibration
  74. GRB 080413A: Suzaku/WAM and Swift/BAT joint spectral analysis
  75. GRB 080413B: Rapid PROMPT Observations
  76. Swift XRT and UVOT observations of GRB080414
  77. GRB 080319B: Jet Break, Energetics, Supernova
  78. GRB 080413B: Faulkes Telescope South optical afterglow observations
  79. GRB 080413A: Liverpool Telescope and Faulkes Telescope South optical observations
  80. GRB 080413A: Suzaku WAM observation of the prompt emission
  81. GRB 080413B: Suzaku WAM observation of the prompt emission
  82. GRB 080413A: MOA-II optical afterglow observations
  83. GRB 080319B: Continued Gemini-N monitoring
  84. GRB 080414: RTT150 optical observations
  85. GRB 080414 Watcher observations
  86. GRB 080414: A long GRB detected by INTEGRAL
  87. VLA radio observations of GRB 080413B
  88. GRB 080413A: Gemini-South Spectroscopy
  89. GRB 080413B: Gemini-South Spectroscopy
  90. VLA radio observations of GRB 080413A
  91. IBAS Alert n. 5257 : not a GRB
  92. GRB 080413B: Ep,i-Eiso correlation
  93. GRB080413B
  94. Swift-BAT spectral lag analysis of GRB 080413B
  95. GRB 080413a, SMARTS optical/IR afterglow observations
  96. GRB 080413B: Swift XRT refined analysis
  97. GRB080413A: Swift/UVOT observations
  98. GRB 080413B, Swift-BAT refined analysis
  99. GRB 080413A: Swift-XRT refined analysis
  100. GRB 080413A, Swift-BAT refined analysis

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