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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"

5401 results found.

  1. GRB 090422: Swift detection of a burst
  2. GRB 090418B: GRAS002 observatios
  3. GRB 090418B: GROND observations
  4. GRB 090417B: Liverpool Telescope observations
  5. GRB 090417B: Swift detection of a burst
  6. Swift-BAT trigger 348781: almost certainly not a burst
  7. GRB 090403: Fermi GBM detection
  8. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  9. GRB 090331: Fermi GBM detection
  10. GRB 090323: Radio afterglow detection
  11. GRB 090323: Additional Lick observations
  12. GRB 090323: Lick observations
  13. GRB 090323: UVOT Detection of Afterglow
  14. GRB 090323: Swift-XRT refined analysis
  15. GRB 090323 Gemini-South Redshift
  16. GRB 090323: GROND Detection of the Afterglow and Photo-z
  17. GRB 090323: Possible XRT Counterpart
  18. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  19. GRB 090313, SMARTS optical/IR observations
  20. GRB 090313: MITSuME Okayama observation
  21. GRB 090313: Additional Gemini-S photometry
  22. GRB 090313 - PAIRITEL NIR detections
  23. GRB 090313: Gemini-S redshift
  24. GRB 090313 optical observations
  25. Swift trigger 346250 is probably not a burst
  26. GRB 090306B: INTEGRAL SPI-ACS light curve
  27. GRB 090308: Swift detection of a burst
  28. Swift Trigger 345551 is probably not a GRB
  29. GRB 090306: Swift detection of a possible burst
  30. GRB 090305: Swift-XRT refined analysis
  31. GRB 090303: Fermi GBM detection
  32. Ongoing activity of AXP/SGR 1E1547.0-5408
  33. IPN localization of GRB 090217
  34. GRB 090205: GROND observations and photometric redshift estimate
  35. GRB 090205: Swift detection of a burst
  36. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  37. GRB 090129: Swift detection of a burst
  38. Suzaku ToO Observation of AXP 1E 1547.0-5408
  39. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  40. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  41. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  42. GRB 090118: Swift-XRT observations
  43. GRB090102: MAGIC telescope GeV observation
  44. Fermi/GBM detection of GRB 081226A
  45. GRB 081231: Fermi GBM Detection
  46. GRB 090102: GRT Optical Observation
  47. Swift triggered on the HMXB 1A 1118-61
  48. GRB 090102: P60 Imaging and P200 Spectroscopy
  49. GRB 090102: NOT redshift
  50. GRB 090102: Swift detection of a burst with an optical counterpart
  51. GRB 081226C: Fermi GBM detection
  52. GRB 081226: Swift detection of a possible short-hard burst
  53. GRB 080810: optical observations
  54. GRB 081223: Fermi GBM detection
  55. GRB081222 optical limit by "Pi of the Sky"
  56. GRB 081221: Gemini-N nIR imaging
  57. GRB 081221: further NOT observations
  58. GRB 081221: NOT observations
  59. IPN localization of short hard GRB 081216
  60. GRB 081203A: optical observations
  61. GRB 081203B: Suzaku WAM observation of the prompt emission
  62. GRB081203B: optical observations
  63. GRB081203A: MITSuME optical observation
  64. GRB081203A: optical observation
  65. GRB 081203A: optical observations
  66. GRB081203: optical observation
  67. GRB 081129: Fermi GBM detection
  68. GRB 081126: GRT Optical Observation
  69. GRB 081118: Fermi GBM detection.
  70. GRB 081109A: confirmation of possible detection host galaxy
  71. GRB 081102: RTT150 Optical observations
  72. GRB 081109A: Faulkes Telescope South observations
  73. GRB 081109A: Swift-XRT refined analysis
  74. GRB 081109: Swift/UVOT upper limits
  75. GRB 081109A optical upper limit
  76. GRB 081109: REM NIR afterglow detection
  77. GRB 081109: Swift detection of a burst
  78. Swift-XRT observations of GRB 081105
  79. Radio observation of GRB 080516 with ATCA
  80. Radio observation of GRB 080411 with ATCA
  81. GRB 081009: Fermi GBM detection
  82. Fermi GBM detection of additional bursts from AXP 1E1547.0-5408
  83. AXP 1E1547.0-5408 (SGR 1550-5418): Fermi GBM detection
  84. GRB 080928A: ROTSE-III Confirmation of Optical Counterpart
  85. GRB080922: A long GRB detected by INTEGRAL
  86. Trigger 324561: IGR J08408-4503 detected by Swift
  87. SGR 0501+4516: preliminary results of the Suzaku ToO observation
  88. GRB 080916B, Swift-BAT refined analysis
  89. GRB 080916B: Enhanced Swift-XRT position
  90. GRB 080916B: Swift-XRT afterglow detection
  91. GRB 080915: ROTSE-III Optical Limits
  92. SGR J0501+4516: radio pulsar searches with GBT and WSRT
  93. GRB 080903: Liverpool Telescope observations
  94. GRB 080828: SuperAGILE GRB Localization
  95. SGR 0501+4516: Decline in Activity
  96. SGR 0501+4516: GMRT Radio Observation at 618 MHz
  97. SGR 0501+4516: radio pulsar searches with GBT and WSRT
  98. GLAST Burst Monitor detection of GRB 080817
  99. GRB 080810: Liverpool Telescope observations
  100. GRB 080727B: IR photometry

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