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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"

4716 results found.

  1. GRB 090323: optical observations
  2. GRB 090429A: ROVOR magnitude limit
  3. GRB 090426: optical observations
  4. GRB 090429D: Fermi GBM detection
  5. GRB 090424: YNAO-GMG observations
  6. GRB 090426: GAO 150cm telescope Optical Observation
  7. GRB 090429B: Swift detection of a burst
  8. GRB 090424: Continued R-band monitoring
  9. GRB 090425: Fermi GBM detection
  10. GRB 090426: Okayama MITSuME optical observation
  11. GRB 090426: TNT confimation of optical counterpart
  12. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  13. GRB 090422: Fermi GBM observation
  14. GRB 080408A: GAO 150cm telescope Optical Observation
  15. GRB 090422: Liverpool Telescope observations
  16. GRB 090422: Swift detection of a burst
  17. GRB 090418B: GRAS002 observatios
  18. GRB 090418B: GROND observations
  19. GRB 090417B: Liverpool Telescope observations
  20. GRB 090417B: Swift detection of a burst
  21. Swift-BAT trigger 348781: almost certainly not a burst
  22. GRB 090403: Fermi GBM detection
  23. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  24. GRB 090331: Fermi GBM detection
  25. GRB 090323: Radio afterglow detection
  26. GRB 090323: Additional Lick observations
  27. GRB 090323: Lick observations
  28. GRB 090323: UVOT Detection of Afterglow
  29. GRB 090323: Swift-XRT refined analysis
  30. GRB 090323 Gemini-South Redshift
  31. GRB 090323: GROND Detection of the Afterglow and Photo-z
  32. GRB 090323: Possible XRT Counterpart
  33. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  34. GRB 090313, SMARTS optical/IR observations
  35. GRB 090313: MITSuME Okayama observation
  36. GRB 090313: Additional Gemini-S photometry
  37. GRB 090313 - PAIRITEL NIR detections
  38. GRB 090313: Gemini-S redshift
  39. GRB 090313 optical observations
  40. Swift trigger 346250 is probably not a burst
  41. GRB 090306B: INTEGRAL SPI-ACS light curve
  42. GRB 090308: Swift detection of a burst
  43. Swift Trigger 345551 is probably not a GRB
  44. GRB 090306: Swift detection of a possible burst
  45. GRB 090305: Swift-XRT refined analysis
  46. GRB 090303: Fermi GBM detection
  47. Ongoing activity of AXP/SGR 1E1547.0-5408
  48. IPN localization of GRB 090217
  49. GRB 090205: GROND observations and photometric redshift estimate
  50. GRB 090205: Swift detection of a burst
  51. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  52. GRB 090129: Swift detection of a burst
  53. Suzaku ToO Observation of AXP 1E 1547.0-5408
  54. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  55. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  56. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  57. GRB 090118: Swift-XRT observations
  58. GRB090102: MAGIC telescope GeV observation
  59. Fermi/GBM detection of GRB 081226A
  60. GRB 081231: Fermi GBM Detection
  61. GRB 090102: GRT Optical Observation
  62. Swift triggered on the HMXB 1A 1118-61
  63. GRB 090102: P60 Imaging and P200 Spectroscopy
  64. GRB 090102: NOT redshift
  65. GRB 090102: Swift detection of a burst with an optical counterpart
  66. GRB 081226C: Fermi GBM detection
  67. GRB 081226: Swift detection of a possible short-hard burst
  68. GRB 080810: optical observations
  69. GRB 081223: Fermi GBM detection
  70. GRB081222 optical limit by "Pi of the Sky"
  71. GRB 081221: Gemini-N nIR imaging
  72. GRB 081221: further NOT observations
  73. GRB 081221: NOT observations
  74. IPN localization of short hard GRB 081216
  75. GRB 081203A: optical observations
  76. GRB 081203B: Suzaku WAM observation of the prompt emission
  77. GRB081203B: optical observations
  78. GRB081203A: MITSuME optical observation
  79. GRB081203A: optical observation
  80. GRB 081203A: optical observations
  81. GRB081203: optical observation
  82. GRB 081129: Fermi GBM detection
  83. GRB 081126: GRT Optical Observation
  84. GRB 081118: Fermi GBM detection.
  85. GRB 081109A: confirmation of possible detection host galaxy
  86. GRB 081102: RTT150 Optical observations
  87. GRB 081109A: Faulkes Telescope South observations
  88. GRB 081109A: Swift-XRT refined analysis
  89. GRB 081109: Swift/UVOT upper limits
  90. GRB 081109A optical upper limit
  91. GRB 081109: REM NIR afterglow detection
  92. GRB 081109: Swift detection of a burst
  93. Swift-XRT observations of GRB 081105
  94. Radio observation of GRB 080516 with ATCA
  95. Radio observation of GRB 080411 with ATCA
  96. GRB 081009: Fermi GBM detection
  97. Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
  98. AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
  99. GRB 080928A: ROTSE-III Confirmation of Optical Counterpart
  100. GRB080922: A long GRB detected by INTEGRAL

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