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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"

28047 results found.

  1. GRB 090201: Swift-BAT refined analysis
  2. GRB 090201: VLT afterglow candidate
  3. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  4. GRB090113: MAGIC telescope GeV observation
  5. GRB 090201: ROTSE-III Optical Limits
  6. GRB 090126A: Swift/UVOT Upper Limits
  7. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  8. GRB 090129: Swift-BAT refined analysis
  9. GRB 090129: Swift detection of a burst
  10. Suzaku ToO Observation of AXP 1E 1547.0-5408
  11. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  12. GRB 090102: HST observations and host galaxy
  13. GRB 090126C: Fermi GBM detection
  14. GRB 090126A: Swift-XRT Refined Analysis
  15. GRB 090126B: Fermi GBM detection
  16. GRB 090126: SuperAGILE Localization of a Long GRB
  17. GRB 090118: no afterglow candidate
  18. GRB 090123: GROND detection
  19. 1E1547.0-5408: Swift detection of dust halo
  20. GRB 090123: Swift XRT refined analysis
  21. GRB 090123: Swift/UVOT Observations
  22. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  23. GRB 090123: Swift-BAT refined analysis
  24. GRB090123: Enhanced Swift-XRT position
  25. GRB 090123: Swift detection of a burst
  26. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  27. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  28. GRB 090117C: Suzaku WAM observation of the prompt emission
  29. Trigger 340734: Swift detection of a possible short burst
  30. GRB 090118: Subaru NIR Observation
  31. GRB 090118: KPNO 4m 2nd Epoch Observations
  32. GRB 090118 (BATSS): GRT Optical Observation
  33. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  34. GRB 090118: Swift-XRT observations
  35. GRB090118 Swift/UVOT upper limits
  36. GRB 090118: GROND Upper Limits
  37. GRB 090118: Possible burst detection from Swift-BAT slew data
  38. GRB 090117B : Fermi GBM detection
  39. GRB 090117C - Fermi GRB Detection
  40. GRB 090117 - Fermi GBM Observations
  41. GRB 090117: GROND Upper Limits
  42. GRB090117 Swift/UVOT upper limits
  43. GRB090117: Swift-XRT detection of a possible candidate afterglow
  44. GRB 090117 - SuperAGILE Localization of a long GRB
  45. GRB 090112B: Suzaku WAM observation of the prompt emission
  46. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  47. GRB 090113: Swift UVOT upper limits
  48. GRB 090113: GROND Upper Limits
  49. GRB 090113: Swift-XRT refined analysis
  50. GRB 090113: Observations from NOT
  51. GRB 090113: Enhanced Swift-XRT position
  52. GRB 090113: Swift-BAT refined analysis
  53. GRB 090113: ROTSE-III Optical Limits
  54. GRB 090112B: Fermi GBM Detection
  55. GRB 090113: Swift detection of a burst
  56. GRB 090112: Fermi GBM detection
  57. GRB 090109: Fermi GBM detection
  58. GRB 090108B: Fermi GBM detection
  59. GRB 090111, Swift-BAT refined analysis
  60. GRB 090111: Swift UVOT Upper Limits
  61. GRB 090108: Fermi GBM Detection
  62. GRB 090111: Swift-XRT refined analysis
  63. GRB 090111: Enhanced Swift-XRT position
  64. GRB 090111: Swift detection of a burst
  65. GRB 090107B: Suzaku WAM observation of the prompt emission
  66. GRB090107B: Fermi GBM Detection
  67. GRB 090107B: Swift XRT afterglow confirmation
  68. GRB 090107B: Swift/UVOT Observations
  69. GRB 090107B: Swift-XRT detection of possible afterglow
  70. GRB 090107B: a long GRB localized by INTEGRAL
  71. Fermi/GBM detection of GRB 081226A
  72. Fermi/GBM detection of GRB 081225
  73. GRB 090107: Swift-BAT refined analysis
  74. GRB 081231: Fermi GBM Detection
  75. VLA radio upper limit on GRB 090102
  76. GRB 090102: GRT Optical Observation
  77. Swift triggered on the HMXB 1A 1118-61
  78. GRB 081229: Fermi GBM detection
  79. GRB 090102: P60 Imaging and P200 Spectroscopy
  80. GRB 090102 Observations from IAC80
  81. GRB 090102: GROND observations of the optical afterglow
  82. GRB 090102: Swift-BAT refined analysis
  83. GRB 090102: Swift XRT refined analysis
  84. GRB 090102: NOT redshift
  85. GRB 090102: Enhanced Swift-XRT position
  86. GRB 090102: REM observations of a bright afterglow
  87. GRB 090102: Swift detection of a burst with an optical counterpart
  88. GRB 090102: TAROT Calern observatory optical observations
  89. GRB 081230: GROND confirmation of the afterglow
  90. GRB 081230, Swift-BAT refined analysis
  91. GRB081230: Swift-XRT refined analysis
  92. GRB 081230 Swift/UVOT Observations
  93. GRB 081230: Enhanced Swift-XRT position
  94. GRB 081230: ROTSE-III Detection of Optical Counterpart
  95. GRB 081230: Swift detection of a burst
  96. GRB 081226C: Fermi GBM detection
  97. GRB 081228, Swift-BAT refined analysis
  98. VLA radio detection of GRB 081221
  99. GRB 081228: Swift/UVOT Upper Limits
  100. GRB 081228: Swift-XRT Team refined analysis

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