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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. GRB100925A/MAXI J1659-152 MITSuME Ishigakijima and Okayama Optical Observation
  2. GRB 100925A / MAXI J1659-152: SARA-S Observations
  3. GRB 100925A/MAXI J1659-152: Submm observations from APEX
  4. GRB100925A/MAXI J1659-152: Galactic origin from SED analysis
  5. GRB 100925A/MAXI J1659-152 - NOT optical observations
  6. GRB 100925A / MAXI J1659-152: BOOTES-2/TELMA and IAC80 optical observations
  7. MAXI J1659-152: Swift-BAT refined analysis (triggers 434928 and 434931)
  8. GRB 100925A: Nearby DSS Source - SN-GRB or new Galactic transient?
  9. GRB100925A UVOT afterglow
  10. GRB 100924A: GROND detection of an optical/NIR afterglow
  11. GRB 100925A: Swift detection of a burst
  12. GRB 100924A: Swift-BAT refined analysis
  13. GRB 100924A: Swift detection of a burst
  14. GRB 100917A: TAROT La Silla observatory optical observations
  15. GRB 100915A: TAROT Calern observatory optical observations
  16. GRB100906A: Ashra-1 observation of early optical emission
  17. GRB 100916A: Fermi GBM detection
  18. GRB 100917A: Swift-BAT refined analysis
  19. GRB 100917A: Swift detection of a burst
  20. GRB100915A: MITSuME Ishigakijima Optical upper limits
  21. GRB 100915B: GRT Optical Observation
  22. GRB 100915A: GRT Optical Observation
  23. GRB 100915B: Fermi GBM observation
  24. GRB 100915A: Correction to Swift-BAT refined analysis
  25. GRB 100915A: Swift/UVOT Upper Limits
  26. GRB 100915A: Swift-BAT refined analysis
  27. GRB 100915A: Swift-XRT refined analysis
  28. GRB 100915A: Enhanced Swift-XRT position
  29. GRB 100915B: a long GRB detected by INTEGRAL
  30. GRB 100915A: Swift detection of a likely burst
  31. GRB 100910A: Fermi GBM detection
  32. Swift-BAT trigger 433953 is not a burst
  33. Swift BAT Trigger 433953 probably not a GRB
  34. GRB100909A: MITSuME Ishigakijima Optical upper limits
  35. GRB 100909A: Swift/UVOT observations
  36. GRB 100901A: errata of GRB name in GCN 11270
  37. GRB 100901A: optical observations in Mondy and R-light curve
  38. GRB100909A: NOT optical afterglow confirmation
  39. GRB 100909A: Swift-XRT refined analysis
  40. GRB 100906A: optical observations at Mt.Terskol
  41. GRB 100901A: optical observation in Maidanak, break confirmation
  42. GRB 100909A: Faulkes Telescope North afterglow candidate
  43. GRB 100909A: ROTSE-III Optical Limits
  44. GRB 100909A: Planned XMM-Newton observation
  45. GRB 100902A : Confirmation of afterglow and re-brightening with CFHT r’-band imaging
  46. GRB 100909A: Swift target of opportunity observation
  47. GRB 100909A: a long GRB detected by INTEGRAL
  48. GRB100906A: detection at 15GHz
  49. GRB100901A: IAO optical upper limits at 4 days after the burst
  50. EVLA detection of radio afterglow of GRB100901A
  51. GRB 100901A: Confirmation of WSRT Radio Detection
  52. GRB 100901A: CrAO optical observations
  53. GRB 100906A: RTT150 optical observations
  54. GRB 100906A: GRAS-007 optical observations
  55. GRB100906A: R band observations
  56. Konus-Wind observation of GRB 100906A
  57. GRB100906A: non-detection at 15GHz
  58. GRB100906A: Optical observations at IAO
  59. GRB 100906A: Fermi GBM observation
  60. GRB 100906A: TLS Monitoring
  61. GRB 100901A: TLS Detection at 5.5 days
  62. GRB 100906A: Observations at the Virtual Telescope
  63. GRB 100906A: Swift-XRT refined analysis
  64. GRB 100906A: Enhanced Swift-XRT position
  65. GRB 100906A: Swift/UVOT Observations
  66. GRB100906A: Errata of MITSuME Okayama about observation time
  67. GRB100906A: MITSuME Okayama Optical Observation
  68. GRB 100906A: Ondrejov 65cm observations
  69. GRB 100906A: TLS Multicolor Observations
  70. GRB 100905A: Swift/UVOT Upper Limits
  71. GRB 100901A: TLS observations, SDSS calibration, decay slope
  72. GRB 100906A: MASTER preliminary prompt+afterglow lc
  73. GRB 100901A: ISON-NM optical observations
  74. GRB 100906A: Swift-BAT refined analysis
  75. GRB 100906A: UKIRT zYJHK Observation
  76. GRB 100906A: MASTER preliminary polarization prompt light curve
  77. GRB 100906A: Gemini-N/GMOS redshift
  78. GRB 100906A : Faulkes Telescope North optical observations
  79. GRB 100906A: MASTER early OT observations
  80. GRB 100906A: Swift detection of a burst with an optical afterglow
  81. GRB 100829A: MASTER optical observations
  82. GRB100905A: Optical upper limits at IAO
  83. GRB100905A: MITSuME Okayama optical upper limits
  84. GRB 100905A: Swift-XRT refined analysis.
  85. GRB 100905A: UKIRT zJHK Observation
  86. GRB 100901A: Possible WSRT Radio Detection
  87. GRB100905A: 1.5m OSN upper limit
  88. GRB 100905A: Enhanced Swift-XRT position
  89. GRB 100905A: Swift-BAT refined analysis
  90. GRB100904A: BOOTES-3 Upper Limit
  91. GRB 100905A: MASTER Prompt Optical Observations
  92. GRB 100905A: Faulkes Telescope North observations
  93. GRB 100905A: Swift detection of a burst
  94. Optical observations of GRB 100901A
  95. GRB10901A: Murikabushi telescope observation at 3 days after the burst
  96. GRB 100901A: Submm observations from SMA
  97. GRB 100902A: UKIRT JK Observation
  98. GRB 100902A: GROND observations; afterglow candidate
  99. GRB 100901A: UKIRT zYJHK Observation
  100. GRB 100904A: Swift-BAT refined analysis

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