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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"

28083 results found.

  1. GRB 101011A: XRT Refined Analysis
  2. GRB 101011A: Swift/UVOT Observations of a Possible Optical Afterglow
  3. GRB 101011A: Enhanced Swift-XRT position
  4. GRB 101011A: Swift-BAT refined analysis
  5. GRB 101011A: Swift detection of a burst
  6. GRB 101008A: Swift-BAT refined analysis
  7. GRB101008A, GROND detection of a fading afterglow
  8. GRB 101008A: Swift-XRT refined analysis
  9. GRB 101008A: SAO RAS optical observations
  10. GRB 100915 optical upper limit
  11. GRB 101008: Swift/UVOT Upper Limits
  12. GRB 101008A: Enhanced Swift-XRT position
  13. GRB 101008A: Swift/XRT Detection of an Afterglow with no UVOT Counterpart
  14. GRB 101008A: Swift detection of a burst
  15. Refined analysis shows Swift Trigger 435520 is not a GRB
  16. Swift Trigger 435520 is probably not a GRB
  17. GRB 100925A / MAXI J1659-152: MASTER optical observations
  18. GRB 100924A: Suzaku WAM observation of the prompt emission
  19. GRB 100928A, Swift-BAT refined analysis
  20. GRB 100924A: Fermi GBM observation
  21. GRB 100928A: Swift detection of a burst
  22. GRB100925A/MAXI J1659-152 MITSuME Ishigakijima and Okayama Optical Observation
  23. GRB 100925A / MAXI J1659-152: SARA-S Observations
  24. GRB 100925A/MAXI J1659-152: Submm observations from APEX
  25. GRB100925A/MAXI J1659-152: Galactic origin from SED analysis
  26. GRB 100925A/MAXI J1659-152 - NOT optical observations
  27. GRB 100925A / MAXI J1659-152: BOOTES-2/TELMA and IAC80 optical observations
  28. GRB 100925A: Nearby DSS Source - SN-GRB or new Galactic transient?
  29. GRB100925A UVOT afterglow
  30. GRB 100924A: GROND detection of an optical/NIR afterglow
  31. GRB 100925A: Swift detection of a burst
  32. GRB 100924A: Swift-BAT refined analysis
  33. GRB 100917A: TAROT La Silla observatory optical observations
  34. GRB 100915A: TAROT Calern observatory optical observations
  35. GRB100906A: Ashra-1 observation of early optical emission
  36. GRB 100916A: Fermi GBM detection
  37. GRB 100917A: Swift-BAT refined analysis
  38. GRB 100917A: Swift detection of a burst
  39. GRB100915A: MITSuME Ishigakijima Optical upper limits
  40. GRB 100915B: GRT Optical Observation
  41. GRB 100915A: GRT Optical Observation
  42. GRB 100915B: Fermi GBM observation
  43. GRB 100915A: Correction to Swift-BAT refined analysis
  44. GRB 100915A: Swift/UVOT Upper Limits
  45. GRB 100915A: Swift-BAT refined analysis
  46. GRB 100915A: Swift-XRT refined analysis
  47. GRB 100915A: Enhanced Swift-XRT position
  48. GRB 100915B: a long GRB detected by INTEGRAL
  49. GRB 100915A: Swift detection of a likely burst
  50. GRB 100910A: Fermi GBM detection
  51. Swift BAT Trigger 433953 probably not a GRB
  52. GRB100909A: MITSuME Ishigakijima Optical upper limits
  53. GRB 100909A: Swift/UVOT observations
  54. GRB 100901A: errata of GRB name in GCN 11270
  55. GRB 100909A: Swift-XRT refined analysis
  56. GRB 100906A: optical observations at Mt.Terskol
  57. GRB 100901A: optical observation in Maidanak, break confirmation
  58. GRB 100909A: Faulkes Telescope North afterglow candidate
  59. GRB 100902A : Confirmation of afterglow and re-brightening with CFHT r’-band imaging
  60. GRB 100909A: Swift target of opportunity observation
  61. GRB100906A: detection at 15GHz
  62. GRB100901A: IAO optical upper limits at 4 days after the burst
  63. GRB100906A: R band observations
  64. GRB100906A: non-detection at 15GHz
  65. GRB100906A: Optical observations at IAO
  66. GRB 100906A: Fermi GBM observation
  67. GRB 100906A: Swift-XRT refined analysis
  68. GRB 100906A: Enhanced Swift-XRT position
  69. GRB 100906A: Swift/UVOT Observations
  70. GRB100906A: MITSuME Okayama Optical Observation
  71. GRB 100905A: Swift/UVOT Upper Limits
  72. GRB 100901A: TLS observations, SDSS calibration, decay slope
  73. GRB 100906A: MASTER preliminary prompt+afterglow lc
  74. GRB 100906A: Swift-BAT refined analysis
  75. GRB 100906A: Swift detection of a burst with an optical afterglow
  76. GRB 100829A: MASTER optical observations
  77. GRB100905A: Optical upper limits at IAO
  78. GRB100905A: MITSuME Okayama optical upper limits
  79. GRB 100905A: Swift-XRT refined analysis.
  80. GRB100905A: 1.5m OSN upper limit
  81. GRB 100905A: Enhanced Swift-XRT position
  82. GRB 100905A: Swift-BAT refined analysis
  83. GRB 100905A: Faulkes Telescope North observations
  84. GRB 100905A: Swift detection of a burst
  85. GRB10901A: Murikabushi telescope observation at 3 days after the burst
  86. GRB 100901A: Submm observations from SMA
  87. GRB 100904A: Swift-BAT refined analysis
  88. GRB100902A: Optical upper limits at IAO
  89. GRB10901A: Optical observations at IAO
  90. GRB 100902A: Swift-BAT refined analysis
  91. IPN Triangulation of the very bright GRB 100829A
  92. GRB 100902A: Swift XRT refined analysis
  93. GRB 100902A: Swift/UVOT Upper Limits
  94. GRB 100902A: optical observation at Mt.Terskol
  95. GRB 100901A: optical observation at Mt.Terskol
  96. GRB100901A: MITSuME Okayama Optical Observation at 1 day after the burst
  97. GRB 100902A: Enhanced Swift-XRT position
  98. GRB 100901A: TLS Observations: Break?
  99. GRB 100901A: ISON-NM optical observations
  100. GRB 100902A: Faulkes Telescope South observations

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