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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"

27400 results found.

  1. GRB 090309: Swift/UVOT Upper Limits
  2. GRB090305B: Fermi GBM detection
  3. GRB 090309B: Fermi GBM detection
  4. GRB 090309: Swift-XRT refined analysis
  5. GRB 090306B: INTEGRAL SPI-ACS light curve
  6. GRB 090309, Swift-BAT refined analysis
  7. GRB 090308: GROND observations
  8. GRB 090309: Swift detection of a burst
  9. GRB 090308B: Fermi GBM detection
  10. GRB 090308: Swift/UVOT Upper Limits
  11. GRB 090307B: Fermi GBM detection
  12. GRB 090306C: Fermi GBM detection
  13. GRB 090307: GROND Upper Limits
  14. GRB 090306B: GROND Upper Limits
  15. GRB 090308: Swift-XRT refined analysis
  16. ATCA observation of SGR J1550-5418
  17. GRB 090308: Swift-BAT refined analysis
  18. GRB 090308: Swift detection of a burst
  19. GRB 090306B: Possible XRT afterglow
  20. GRB 090307: Swift-XRT afterglow confirmation and analysis
  21. GRB 090307: Swift-BAT refined analysis of trigger 345551
  22. GRB 090306B: Burst detection from Swift-BAT slew data
  23. Swift Trigger 345551 is probably not a GRB
  24. Swift-BAT trigger 345396 is not a GRB
  25. IPN localization of short GRB 090305C
  26. Fermi GBM trigger 090305784 is not a GRB
  27. GRB 090306: Swift detection of a possible burst
  28. GRB 090305: Swift/UVOT Upper Limits
  29. GRB 090305: Swift-XRT refined analysis
  30. GRB 090305, Swift-BAT refined analysis
  31. GRB 090305: Magellan confirmation of the optical afterglow
  32. GRB090305: GMOS-S Candidate Optical Afterglow
  33. GRB 090305: Swift detection of a short burst
  34. GRB 090303: Fermi GBM detection
  35. GRB 090304: Fermi GBM detection
  36. GRB 090301A: Suzaku WAM observation of the prompt emission
  37. Konus-RF catches first GRB and SGR bursts
  38. GRB 090228B: Fermi GBM detection
  39. Konus-Wind observation of bright short GRB 090227B
  40. IPN localization of short bright GRB 090227B
  41. Konus-Wind observation of GRB 090301A
  42. GRB 090301A: Swift-BAT refined analysis
  43. GRB 090301B: Fermi GBM detection
  44. GRB 090227B: Fermi GBM detection
  45. GRB 090301: Swift detection of a burst
  46. Swift_BAT_Lightcurve Notice for Trigger Number 344565 is not valid
  47. GRB 090228: Fermi GBM detection
  48. GRB 090227: Fermi GBM detection
  49. GRB 090206: Fermi GBM detection
  50. SGR J1550-5418
  51. GRB 081211B: Nearby cluster
  52. Ongoing activity of AXP/SGR 1E1547.0-5408
  53. GRB 090222: Fermi GBM detection
  54. GRB 090219: Fermi GBM detection
  55. Swift Restored
  56. Swift Trigger 343319 is not a GRB
  57. GRB 090217: Suzaku WAM observation of the prompt emission
  58. GRB090217: XRT analysis
  59. Konus-Wind observation of GRB 090217
  60. IPN localization of GRB 090217
  61. GRB 090213: Fermi GBM detection
  62. GRB090217: Fermi-LAT Detection
  63. GRB 090217: Fermi GBM detection
  64. SGR activity seen by BAT during ICSP Ionospheric Events
  65. GRB 090207 - Fermi GBM Observations
  66. Fermi Gamma-ray Burst Monitor trigger 255729682 is not a GRB
  67. GRB 090129: Fermi GBM detection
  68. Fermi Gamma-ray Burst Monitor trigger 255541748 cannot be classified
  69. GRB 090205: Swift/UVOT Upper Limits
  70. GRB 090205: Swift-XRT refined analysis
  71. GRB 090205: GROND observations and photometric redshift estimate
  72. GRB 090205: Swift-BAT refined analysis
  73. GRB 090205: Swift detection of a burst
  74. GRB 090126A: Swift-XRT afterglow confirmation
  75. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  76. Konus-Wind observation of GRB 090201
  77. GRB 090202: Fermi GBM detection
  78. GRB 090131: Fermi GBM detection
  79. GRB 090201: Swift-XRT refined analysis
  80. GRB090201: Swift UVOT upper limits
  81. GRB 090201: Swift-BAT refined analysis
  82. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  83. GRB090113: MAGIC telescope GeV observation
  84. GRB 090201: ROTSE-III Optical Limits
  85. GRB 090201: Swift detection of a burst
  86. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  87. GRB 090129: Swift-BAT refined analysis
  88. GRB 090129: Swift detection of a burst
  89. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  90. GRB 090126C: Fermi GBM detection
  91. GRB 090126A: Swift-XRT Refined Analysis
  92. GRB 090126B: Fermi GBM detection
  93. GRB 090123: GROND detection
  94. GRB 090123: Swift XRT refined analysis
  95. GRB 090123: Swift/UVOT Observations
  96. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  97. GRB 090123: Swift-BAT refined analysis
  98. GRB 090123: Swift detection of a burst
  99. Swift-BAT trigger 340734 is not a GRB
  100. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts

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