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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"

5523 results found.

  1. GRB 090531: GROND upper limits
  2. GRB 090530: PAIRITEL NIR Detections
  3. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  4. GRB 090530: Swift detection of a burst with an optical counterpart
  5. GRB 090516B: Fermi GBM detection
  6. GRB 090418A: optical observation
  7. GRB 090509: Swift detection of a burst
  8. GRB 090323: optical observations
  9. GRB 090429A: ROVOR magnitude limit
  10. GRB 090426: optical observations
  11. GRB 090429D: Fermi GBM detection
  12. GRB 090424: YNAO-GMG observations
  13. GRB 090426: GAO 150cm telescope Optical Observation
  14. GRB 090429B: Swift detection of a burst
  15. GRB 090424: Continued R-band monitoring
  16. GRB 090425: Fermi GBM detection
  17. GRB 090426: Okayama MITSuME optical observation
  18. GRB 090426: TNT confimation of optical counterpart
  19. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  20. GRB 090422: Fermi GBM observation
  21. GRB 080408A: GAO 150cm telescope Optical Observation
  22. GRB 090422: Liverpool Telescope observations
  23. GRB 090422: Swift detection of a burst
  24. GRB 090418B: GRAS002 observatios
  25. GRB 090418B: GROND observations
  26. GRB 090417B: Liverpool Telescope observations
  27. GRB 090417B: Swift detection of a burst
  28. Swift-BAT trigger 348781: almost certainly not a burst
  29. GRB 090403: Fermi GBM detection
  30. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  31. GRB 090331: Fermi GBM detection
  32. GRB 090323: Radio afterglow detection
  33. GRB 090323: Additional Lick observations
  34. GRB 090323: Lick observations
  35. GRB 090323: UVOT Detection of Afterglow
  36. GRB 090323: Swift-XRT refined analysis
  37. GRB 090323 Gemini-South Redshift
  38. GRB 090323: GROND Detection of the Afterglow and Photo-z
  39. GRB 090323: Possible XRT Counterpart
  40. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  41. GRB 090313, SMARTS optical/IR observations
  42. GRB 090313: MITSuME Okayama observation
  43. GRB 090313: Additional Gemini-S photometry
  44. GRB 090313 - PAIRITEL NIR detections
  45. GRB 090313: Gemini-S redshift
  46. GRB 090313 optical observations
  47. Swift trigger 346250 is probably not a burst
  48. GRB 090306B: INTEGRAL SPI-ACS light curve
  49. GRB 090308: Swift detection of a burst
  50. Swift Trigger 345551 is probably not a GRB
  51. GRB 090306: Swift detection of a possible burst
  52. GRB 090305: Swift-XRT refined analysis
  53. GRB 090303: Fermi GBM detection
  54. Ongoing activity of AXP/SGR 1E1547.0-5408
  55. IPN localization of GRB 090217
  56. GRB 090205: GROND observations and photometric redshift estimate
  57. GRB 090205: Swift detection of a burst
  58. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  59. GRB 090129: Swift detection of a burst
  60. Suzaku ToO Observation of AXP 1E 1547.0-5408
  61. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  62. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  63. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  64. GRB 090118: Swift-XRT observations
  65. GRB090102: MAGIC telescope GeV observation
  66. Fermi/GBM detection of GRB 081226A
  67. GRB 081231: Fermi GBM Detection
  68. GRB 090102: GRT Optical Observation
  69. Swift triggered on the HMXB 1A 1118-61
  70. GRB 090102: P60 Imaging and P200 Spectroscopy
  71. GRB 090102: NOT redshift
  72. GRB 090102: Swift detection of a burst with an optical counterpart
  73. GRB 081226C: Fermi GBM detection
  74. GRB 081226: Swift detection of a possible short-hard burst
  75. GRB 080810: optical observations
  76. GRB 081223: Fermi GBM detection
  77. GRB081222 optical limit by "Pi of the Sky"
  78. GRB 081221: Gemini-N nIR imaging
  79. GRB 081221: further NOT observations
  80. GRB 081221: NOT observations
  81. IPN localization of short hard GRB 081216
  82. GRB 081203A: optical observations
  83. GRB 081203B: Suzaku WAM observation of the prompt emission
  84. GRB081203B: optical observations
  85. GRB081203A: MITSuME optical observation
  86. GRB081203A: optical observation
  87. GRB 081203A: optical observations
  88. GRB081203: optical observation
  89. GRB 081129: Fermi GBM detection
  90. GRB 081126: GRT Optical Observation
  91. GRB 081118: Fermi GBM detection.
  92. GRB 081109A: confirmation of possible detection host galaxy
  93. GRB 081102: RTT150 Optical observations
  94. GRB 081109A: Faulkes Telescope South observations
  95. GRB 081109A: Swift-XRT refined analysis
  96. GRB 081109: Swift/UVOT upper limits
  97. GRB 081109A optical upper limit
  98. GRB 081109: REM NIR afterglow detection
  99. GRB 081109: Swift detection of a burst
  100. Swift-XRT observations of GRB 081105

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