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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"

5046 results found.

  1. GRB 090727: Liverpool Telescope possible OT candidate
  2. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  3. Konus-Wind and Konus-RF observations of GRB 090715B
  4. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  5. GRB 090712: Fermi GBM observation
  6. GRB 090712: Swift detection of a burst
  7. GRB 090708 : Fermi GBM detection
  8. GRB 090708: Early RAPTOR Optical Limits
  9. GRB 090708: ROTSE-III Optical Limits
  10. GRB 090708: Swift detection of a burst
  11. GRB 090703: Fermi GBM detection
  12. GRB 090313: optical observations
  13. GRB 090626: IPN localization
  14. GRB 090625B: GROND upper limits
  15. GRB 090618: RTT150 optical observations
  16. GRB090618: OAA-OAUV Optical observations
  17. GRB 090616: Fermi GBM detection
  18. RXTE Discovery of Pulsations from SGR 0418+5729
  19. GRB 090530: RTT150 Optical Observation
  20. GRB 090531B: GROND observation
  21. GRB 090530: Early RAPTOR Optical Observations
  22. GRB 090529: MITSuME optical observation
  23. GRB 090530: GRT Optical Observation
  24. GRB 090531: GROND upper limits
  25. GRB 090530: PAIRITEL NIR Detections
  26. GRB 090530A: ROTSE-III Detection of Optical Counterpart
  27. GRB 090530: Swift detection of a burst with an optical counterpart
  28. GRB 090516B: Fermi GBM detection
  29. GRB 090418A: optical observation
  30. GRB 090509: Swift detection of a burst
  31. GRB 090323: optical observations
  32. GRB 090429A: ROVOR magnitude limit
  33. GRB 090426: optical observations
  34. GRB 090429D: Fermi GBM detection
  35. GRB 090424: YNAO-GMG observations
  36. GRB 090426: GAO 150cm telescope Optical Observation
  37. GRB 090429B: Swift detection of a burst
  38. GRB 090424: Continued R-band monitoring
  39. GRB 090425: Fermi GBM detection
  40. GRB 090426: Okayama MITSuME optical observation
  41. GRB 090426: TNT confimation of optical counterpart
  42. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  43. GRB 090422: Fermi GBM observation
  44. GRB 080408A: GAO 150cm telescope Optical Observation
  45. GRB 090422: Liverpool Telescope observations
  46. GRB 090422: Swift detection of a burst
  47. GRB 090418B: GRAS002 observatios
  48. GRB 090418B: GROND observations
  49. GRB 090417B: Liverpool Telescope observations
  50. GRB 090417B: Swift detection of a burst
  51. Swift-BAT trigger 348781: almost certainly not a burst
  52. GRB 090403: Fermi GBM detection
  53. Fermi Gamma-ray Burst Monitor trigger 260428446 is not a GRB
  54. GRB 090331: Fermi GBM detection
  55. GRB 090323: Radio afterglow detection
  56. GRB 090323: Additional Lick observations
  57. GRB 090323: Lick observations
  58. GRB 090323: UVOT Detection of Afterglow
  59. GRB 090323: Swift-XRT refined analysis
  60. GRB 090323 Gemini-South Redshift
  61. GRB 090323: GROND Detection of the Afterglow and Photo-z
  62. GRB 090323: Possible XRT Counterpart
  63. IPN Triangulation of GRB090315 and Tupi Detection of Muon Increase
  64. GRB 090313, SMARTS optical/IR observations
  65. GRB 090313: MITSuME Okayama observation
  66. GRB 090313: Additional Gemini-S photometry
  67. GRB 090313 - PAIRITEL NIR detections
  68. GRB 090313: Gemini-S redshift
  69. GRB 090313 optical observations
  70. Swift trigger 346250 is probably not a burst
  71. GRB 090306B: INTEGRAL SPI-ACS light curve
  72. GRB 090308: Swift detection of a burst
  73. Swift Trigger 345551 is probably not a GRB
  74. GRB 090306: Swift detection of a possible burst
  75. GRB 090305: Swift-XRT refined analysis
  76. GRB 090303: Fermi GBM detection
  77. Ongoing activity of AXP/SGR 1E1547.0-5408
  78. IPN localization of GRB 090217
  79. GRB 090205: GROND observations and photometric redshift estimate
  80. GRB 090205: Swift detection of a burst
  81. Fermi Gamma-ray Burst Monitor trigger 255342766 is not a GRB
  82. GRB 090129: Swift detection of a burst
  83. Suzaku ToO Observation of AXP 1E 1547.0-5408
  84. AXP 1E1547.0-5408: RHESSI observations up to 400 keV
  85. AXP 1E1547.0-5408: Fermi GBM detection of additional bursts
  86. GRB 090118: KPNO 4m Detection of Candidate Afterglow
  87. GRB 090118: Swift-XRT observations
  88. GRB090102: MAGIC telescope GeV observation
  89. Fermi/GBM detection of GRB 081226A
  90. GRB 081231: Fermi GBM Detection
  91. GRB 090102: GRT Optical Observation
  92. Swift triggered on the HMXB 1A 1118-61
  93. GRB 090102: P60 Imaging and P200 Spectroscopy
  94. GRB 090102: NOT redshift
  95. GRB 090102: Swift detection of a burst with an optical counterpart
  96. GRB 081226C: Fermi GBM detection
  97. GRB 081226: Swift detection of a possible short-hard burst
  98. GRB 080810: optical observations
  99. GRB 081223: Fermi GBM detection
  100. GRB081222 optical limit by "Pi of the Sky"

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