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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. INTEGRAL ToO Observation of SGR0501+4516
  2. Radio Detection of SGR 0501+4516
  3. SGR 0501+4516: MDM Optical Observations
  4. GRB 080822B, Swift-BAT refined analysis
  5. SGR 0501+4516: Astrotel-Caucasus optical observations
  6. SGR 0501+4516: UKIRT detection of possible infra-red counterpart
  7. SGR 0501+4516: WSRT Radio Observations
  8. Trigger 321551: Continued Large Flaring of SGR 0501+4516
  9. GRB 080822B: MASTER optical observation
  10. New Soft Gamma Repeater 0501+4516 (GRB 080822): GLAST Burst Monitor detection
  11. SGR 0501+4516: optical observations
  12. Swift Trigger 321481: A Large Flare from SGR 0501+4516
  13. SGR 0501+4516: Swift-BAT refined analysis of the 3 discovery events
  14. Discovery of the Spin Period of the New Soft Gamma Repeater SGR 0501+4516
  15. GRB 080822B: Swift detection of a burst
  16. GRB080818B: GLAST Burst Monitor detection
  17. Third event from SGR 0501+4516
  18. GRB 080822 (SGR 0501+4516): archival optical observations
  19. New Soft Gamma Repeater 0501+4516 was GRB 080822
  20. GRB 080822: Swift detection of a short burst
  21. GLAST Burst Monitor detection of a GRB: 080816B
  22. GLAST Burst Monitor detection of GRB 080818
  23. GLAST Burst Monitor detection of GRB080817B
  24. GLAST Burst Monitor detection of GRB 080817
  25. GLAST Burst Monitor detection of GRB080816
  26. GRB080810 - optical observations
  27. GRB080810: optical observations
  28. GLAST Burst Monitor detection of GRB 080812
  29. Radio detection of GRB 080810 with the VLA
  30. GRB 080810: RTT150 optical observations
  31. GRB 080810: Konus-Wind and Swift/BAT joint spectral analysis
  32. GLAST Burst Monitor detection of GRB 080810
  33. GRB 080810: Liverpool and Faulkes North observations
  34. GRB 080810: RTT150 optical observations
  35. GRB080810: MITSuME optical observation
  36. First GLAST Burst Monitor GRB Circulars
  37. GRB 080810: Swift/UVOT Refined Analysis
  38. GRB 080810: optical observations
  39. GRB 080810: Liverpool Telescope observations
  40. GRB 080810: D50 optical observation
  41. GRB 080810: Kanazawa optical observation
  42. GRB 080810: OSN follow-up
  43. GRB 080810: Observations from NOT
  44. GRB 080810: RTT150 optical observations
  45. GRB 080810: Swift-XRT Team refined analysis
  46. GRB 080810: Enhanced Swift-XRT position
  47. GRB 080810: KANATA optical-NIR observation, update
  48. GRB 080810: ROTSE-III Prompt Detection of Optical Counterpart
  49. GRB 080810: Keck/HIRES Spectroscopy
  50. GRB 080810, Swift-BAT refined analysis
  51. GRB 080810 : optical observation with KANATA
  52. GRB 080810: Swift detection of a burst with a bright optical afterglow
  53. GRB 080723B: GROND upper limits
  54. GRB 080723B: XMM-Newton observation
  55. GRB 080805: VLT redshift update
  56. GRB 080805: Faulkes Telescope South optical observations
  57. GRB 080804: GROND observations
  58. GRB 080727B: Late VLT imaging
  59. GRB 080804: ATCA Radio Observations
  60. GRB 080805: Swift-XRT Refined Analysis
  61. GRB 080805: Swift/UVOT Upper Limits
  62. GRB 080804: Swift-XRT Refined Analysis
  63. GRB 080804: Swift/UVOT Refined Analysis
  64. GRB 080805, Swift-BAT refined analysis
  65. GRB 080804, Swift-BAT refined analysis
  66. GRB 080804: Enhanced Swift-XRT position
  67. GRB080804: Gemini South redshift confirmation
  68. GRB 080804: Faulkes Telescope South observations
  69. GRB080805 optical limit by "Pi of the Sky"
  70. GRB 080805: VLT redshift
  71. GRB 080805: Afterglow confirmation
  72. GRB 080805: GROND detection of possible afterglow
  73. GRB 080805: Swift detection of a burst
  74. GRB 080804: UVES redshift
  75. GRB 080804: Swift detection of a burst with optical afterglow
  76. GRB 080804: ROTSE-III Detection of Optical Counterpart
  77. GRB 080802: Swift/UVOT Upper Limits
  78. GRB 080802: Swift-XRT Refined Analysis
  79. GRB 080802: UVI Telescope Upper Limit
  80. GRB 080802, Swift-BAT refined analysis
  81. GRB 080802: Swift detection of a probable burst
  82. GRB 080727C: Suzaku WAM observation of the prompt emission
  83. GRB 080727B: IR photometry
  84. GRB 080727A: Early IR observations
  85. GRB 080727C: TAROT Calern observatory optical observations
  86. GRB 080727B: KAIT photometry and an early lightcurve break
  87. GRB 080727B: GROND redshift limit
  88. GRB 080727C, Swift-BAT refined analysis
  89. GRB 080727C: Swift/UVOT Upper Limits
  90. Konus-Wind observation of GRB 080727B
  91. GRB 080727C: Swift XRT refined analysis
  92. GRB 080727C: Liverpool Telescope observations
  93. GRB 080727A: VLT upper limits
  94. GRB 080727C: Enhanced Swift-XRT position
  95. GRB 080727B: REM NIR afterglow prompt detection
  96. GRB080727C: RTT150 optical observations
  97. GRB 080727C: Swift detection of a burst
  98. Swift detection of XTE J1701-407
  99. GRB 080727B: Swift/UVOT Upper Limits
  100. BAT Trigger 318150 is not a GRB

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