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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. GRB 090201: Swift-XRT detection of the possible X-ray afterglow
  2. GRB090113: MAGIC telescope GeV observation
  3. GRB 090201: ROTSE-III Optical Limits
  4. GRB 090201: Swift detection of a burst
  5. GRB 090126A: Swift/UVOT Upper Limits
  6. Konus-Wind observation of bright burst from AXP/SGR 1E1547.0-5408 on January 29
  7. GRB 090129: Swift-BAT refined analysis
  8. GRB 090129: Swift detection of a burst
  9. IBAS Alert N. 5442 is not a GRB
  10. Suzaku ToO Observation of AXP 1E 1547.0-5408
  11. Konus-Wind observation of AXP/SGR 1E1547.0-5408 bursting activity
  12. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  13. GRB 090102: HST observations and host galaxy
  14. GRB 090126C: Fermi GBM detection
  15. GRB 090126A: Swift-XRT Refined Analysis
  16. GRB 090126B: Fermi GBM detection
  17. GRB 090126: SuperAGILE Localization of a Long GRB
  18. Konus-Wind detection of very bright SGR-like burst on January 25, 2009
  19. GRB 090118: no afterglow candidate
  20. GRB 090123: GROND detection
  21. 1E1547.0-5408: Swift detection of dust halo
  22. GRB 090123: Swift XRT refined analysis
  23. GRB 090123: Swift/UVOT Observations
  24. AXP 1E1547.0-5408: Suzaku WAM detections of the current activity
  25. GRB 090123: Swift-BAT refined analysis
  26. GRB090123: Enhanced Swift-XRT position
  27. GRB 090123: Swift detection of a burst
  28. AXP 1E1547.0-5408: long bursts with INTEGRAL SPI-ACS
  29. GRB 090118: Swift XRT Observations - Confirmation of an Afterglow
  30. Swift-BAT trigger 340734 is not a GRB
  31. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  32. AXP 1E1547.0-5408: INTEGRAL SPI-ACS confirms activity increase
  33. GRB 090117C: Suzaku WAM observation of the prompt emission
  34. AXP 1E1547.0-5408: Fermi GBM observations
  35. Trigger 340734: Swift detection of a possible short burst
  36. AXP 1E1547.0-5408 activity with SGR bursts
  37. GRB 090118: Subaru NIR Observation
  38. GRB 090118: KPNO 4m 2nd Epoch Observations
  39. GRB 090118 (BATSS): GRT Optical Observation
  40. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  41. GRB 090118: Swift-XRT observations
  42. GRB090118 Swift/UVOT upper limits
  43. GRB 090118: GROND Upper Limits
  44. GRB 090118: Possible burst detection from Swift-BAT slew data
  45. GRB 090117B : Fermi GBM detection
  46. GRB 090117: confirmation of the X-ray afterglow
  47. GRB 090117C - Fermi GRB Detection
  48. GRB 090117 - Fermi GBM Observations
  49. GRB 090117: GROND Upper Limits
  50. GRB090117 Swift/UVOT upper limits
  51. GRB090117: Swift-XRT detection of a possible candidate afterglow
  52. GRB 090117 - SuperAGILE Localization of a long GRB
  53. GRB090102: MAGIC telescope GeV observation
  54. GRB 090112B: Suzaku WAM observation of the prompt emission
  55. GRB 090113: LOAO Detection Limits in R, I, z, Y-band
  56. GRB 090113: Swift UVOT upper limits
  57. GRB 090113: GROND Upper Limits
  58. GRB 090113: Swift-XRT refined analysis
  59. GRB 090113: Observations from NOT
  60. GRB 090113: Enhanced Swift-XRT position
  61. GRB 090113: Swift-BAT refined analysis
  62. GRB 090113: ROTSE-III Optical Limits
  63. GRB090113: XRT position
  64. GRB 090112B: Fermi GBM Detection
  65. GRB 090113: Swift detection of a burst
  66. GRB 090112: Fermi GBM detection
  67. GRB 090109: Fermi GBM detection
  68. GRB 090108B: Fermi GBM detection
  69. GRB 090111, Swift-BAT refined analysis
  70. GRB 090111: Swift UVOT Upper Limits
  71. GRB 090108: Fermi GBM Detection
  72. GRB 090111: Swift-XRT refined analysis
  73. GRB 090111: Enhanced Swift-XRT position
  74. GRB 090111: Swift detection of a burst
  75. GRB 090107B: Suzaku WAM observation of the prompt emission
  76. GRB090107B: Fermi GBM Detection
  77. GRB 090102: WSRT Radio Observations
  78. GRB 090107B: Swift XRT afterglow confirmation
  79. GRB 090107B: Swift/UVOT Observations
  80. GRB 090107B: Swift-XRT detection of possible afterglow
  81. GRB 090107B optical observations
  82. GRB 090107B: ROTSE-III Optical Limits
  83. GRB 090107B: a long GRB localized by INTEGRAL
  84. Fermi/GBM detection of GRB 081226A
  85. Fermi/GBM detection of GRB 081225
  86. GRB 090107: Swift-BAT refined analysis
  87. GRB 090107: Swift detection of a burst
  88. GRB 081231: Fermi GBM Detection
  89. GRB 090102: optical decay
  90. VLA radio upper limit on GRB 090102
  91. GRB 090102: GRT Optical Observation
  92. Swift triggered on the HMXB 1A 1118-61
  93. Konus-Wind observation of GRB 090102
  94. GRB 081229: Fermi GBM detection
  95. GRB 090102: Hobby-Eberly Telescope Spectroscopy
  96. GRB 090102: P60 Imaging and P200 Spectroscopy
  97. GRB 090102 Observations from IAC80
  98. GRB 090102: GROND observations of the optical afterglow
  99. Swift UVOT observations of GRB 090102
  100. GRB 090102: Swift-BAT refined analysis

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