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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"

36130 results found.

  1. Swift Trigger 345551 is probably not a GRB
  2. Swift-BAT trigger 345396 is not a GRB
  3. IPN localization of short GRB 090305C
  4. Fermi GBM trigger 090305784 is not a GRB
  5. GRB 090306: Swift detection of a possible burst
  6. GRB 090305: Swift/UVOT Upper Limits
  7. GRB 090305: Swift-XRT refined analysis
  8. GRB 090305, Swift-BAT refined analysis
  9. GRB 090227A: Suzaku WAM observation of the prompt emission
  10. GRB 090305: Magellan confirmation of the optical afterglow
  11. GRB090305: GMOS-S Candidate Optical Afterglow
  12. GRB 090305: Swift detection of a short burst
  13. GRB 090303: Fermi GBM detection
  14. GRB 090304: Fermi GBM detection
  15. GRB 090301A: Suzaku WAM observation of the prompt emission
  16. Konus-RF catches first GRB and SGR bursts
  17. GRB 090228B: Fermi GBM detection
  18. Konus-Wind observation of bright short GRB 090227B
  19. IPN localization of short bright GRB 090227B
  20. Konus-Wind observation of GRB 090301A
  21. GRB 090301A: Swift-BAT refined analysis
  22. GRB 090301B: Fermi GBM detection
  23. GRB 090227B: Fermi GBM detection
  24. GRB 090301: Swift detection of a burst
  25. Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
  26. GRB 090228: Fermi GBM detection
  27. GRB 090227: Fermi GBM detection
  28. GRB 090206: Fermi GBM detection
  29. GRB 081211B: Nearby cluster
  30. GRB 090222: Fermi GBM detection
  31. GRB 090219: Fermi GBM detection
  32. Swift Trigger 343319 is not a GRB
  33. GRB 090217: Suzaku WAM observation of the prompt emission
  34. GRB090217: XRT analysis
  35. Konus-Wind observation of GRB 090217
  36. IPN localization of GRB 090217
  37. GRB 090213: Fermi GBM detection
  38. GRB090217: Fermi-LAT Detection
  39. GRB 090217: Fermi GBM detection
  40. GRB 090207 - Fermi GBM Observations
  41. Fermi Gamma-ray Burst Monitor trigger 255729682 is not a GRB
  42. GRB 090129: Fermi GBM detection
  43. VLA radio upper limit on GRB 090205
  44. GRB 090205: VLT optical decay
  45. Fermi Gamma-ray Burst Monitor trigger 255541748 cannot be classified
  46. GRB 090205: Swift/UVOT Upper Limits
  47. GRB 090205: VLT refined redshift
  48. GRB 090205: Swift-XRT refined analysis
  49. GRB 090205: Swift burst of interest
  50. GRB 090205: VLT spectroscopic redshift
  51. GRB 090205: GROND observations and photometric redshift estimate
  52. GRB 090205: VLT candidate afterglow
  53. GRB 090205: Swift-BAT refined analysis
  54. GRB 090205: Enhanced Swift-XRT position
  55. GRB 090205: Swift detection of a burst
  56. GRB 080319B: IceCube upper limit on high-energy neutrino flux
  57. GRB 090131: Suzaku WAM observation of the prompt emission
  58. GRB 090126A: Swift-XRT afterglow confirmation
  59. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  60. Konus-Wind observation of GRB 090201
  61. GRB 090202: Fermi GBM detection
  62. GRB 090131: Fermi GBM detection
  63. GRB 090201: Swift-XRT refined analysis
  64. GRB090201: Swift UVOT upper limits
  65. GRB 090201: object inside the enhanced XRT error circle
  66. GRB 090201: Enhanced Swift-XRT position
  67. GRB 090201: VLT NIR observations
  68. GRB 090201: Swift-BAT refined analysis
  69. GRB 090201: VLT afterglow candidate
  70. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  71. GRB090113: MAGIC telescope GeV observation
  72. GRB 090201: ROTSE-III Optical Limits
  73. GRB 090201: Swift detection of a burst
  74. GRB 090126A: Swift/UVOT Upper Limits
  75. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  76. GRB 090129: Swift-BAT refined analysis
  77. GRB 090129: Swift detection of a burst
  78. IBAS Alert N. 5442 is not a GRB
  79. GRB 090102: HST observations and host galaxy
  80. GRB 090126C: Fermi GBM detection
  81. GRB 090126A: Swift-XRT Refined Analysis
  82. GRB 090126B: Fermi GBM detection
  83. GRB 090126: SuperAGILE Localization of a Long GRB
  84. GRB 090118: no afterglow candidate
  85. GRB 090123: GROND detection
  86. GRB 090123: Swift XRT refined analysis
  87. GRB 090123: Swift/UVOT Observations
  88. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  89. GRB 090123: Swift-BAT refined analysis
  90. GRB 090123: Swift detection of a burst
  91. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  92. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  93. Swift-BAT trigger 340734 is not a GRB
  94. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  95. GRB 090117C: Suzaku WAM observation of the prompt emission
  96. Trigger 340734: Swift detection of a possible short burst
  97. GRB 090118: Subaru NIR Observation
  98. GRB 090118: KPNO 4m 2nd Epoch Observations
  99. GRB 090118 (BATSS): GRT Optical Observation
  100. GRB 090118: KPNO 4m Detection of Candidate Afterglow

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