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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"

28063 results found.

  1. GRB 050822: refined XRT analysis
  2. GRB 050824: XRT refined analysis and possible afterglow detection
  3. GRB050824: MASTER:OT decay
  4. GRB050824: MASTER observation OT
  5. GRB050805a: MASTER optical candidat
  6. GRB 050824: ROTSE-III Optical Limits
  7. GRB050824: Swift-BAT detection of a burst
  8. GRB050820A: RTT150 optical observations
  9. GRB050820a: PROMPT RcIc Observations
  10. GRB050815: Maidanak optical observation
  11. XRF050509c: Radio upper limits from GMRT
  12. VLT/UVES spectroscopy of GRB050820
  13. GRB050822: Swift/UVOT upper limits
  14. GRB 050822: Swift-BAT refined analysis
  15. GRB050820A: RTT150 optical observations
  16. Swift/UVOT UV Photometry of GRB 050820B
  17. GRB 050822: ROTSE-III Prompt Optical Limits
  18. GRB 050822: Swift detection of a long burst
  19. GRB050820A: Radio Observation
  20. GRB050820a BVRcIc field photometry
  21. GRB050820B XMM-Newton observation
  22. GRB 050820a: NIR Observations by WIRO
  23. GRB 050820B: Swift XRT position
  24. GRB050820B: BAT-Swift detection of a bright GRB
  25. Swift/UVOT photometry of GRB050820
  26. GRB050820: refined XRT analysis
  27. GRB 050820: P60 Temporal Decay Index
  28. GRB 050820: High Resolution Spectroscopy from Keck
  29. GRB050819: refined XRT analysis
  30. GRB 050820: Swift detection of a GRB
  31. GRB050820: Optical afterglow from P60
  32. GRB 050819 Swift-BAT refined analysis
  33. GRB050819: Swift XRT position
  34. GRB050819: Swift-BAT detection of a weak burst
  35. Swift-BAT trigger 150993 is not a GRB
  36. GRB 050815: Radio Observation
  37. GRB050814: Radio Observation
  38. GRB050817: Swift-BAT Detection of a burst
  39. GRB 050814: continued fading
  40. GRB050815: Optical afterglow detection by Swift UVOT
  41. GRB050815: XRT refined analysis
  42. GRB 050813: Radio Observations
  43. GRB050815: Refined analysis of the Swift-BAT burst
  44. GRB 050815: ROTSE-III Optical Limits
  45. GRB050815: Swift XRT afterglow localization
  46. GRB050815: Swift-BAT detection of a burst
  47. GRB 050730: Third Epoch WSRT Radio Observations
  48. GRB050814: Fading red source
  49. GRB 050813: Gemini Spectra Revisited
  50. GRB050814: P60 Optical Afterglow Candidate
  51. GRB 050813: Non-fading of afterglow candidate
  52. GRB 050814: XRT refined analysis
  53. GRB050814: SWIFT/UVOT observation
  54. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  55. GRB 050814: Swift XRT Afterglow Localization
  56. GRB 050814: Swift detection of a burst
  57. GRB 050813: Magellan detection of a high redshift galaxy cluster
  58. GRB 050813: I-band observations
  59. GRB050813, SDSS pre-burst observations
  60. GRB 050813: KAIT optical limit
  61. GRB 050813: Swift-BAT refined analysis
  62. GRB 050813: Photometry of object in XRT error circle
  63. GRB050813: SWIFT/UVOT observation
  64. GRB 050813: Swift XRT afterglow localization
  65. GRB 050813: Possible Short Swift-BAT GRB
  66. Swift-BAT trigger 150131 is not a GRB
  67. GRB050803: CrAO optical observations, no OT candidate
  68. Detection of an intermediate burst from SGR 1806-20 on August 8
  69. GRB 050730: WSRT Radio Observations
  70. GRB 050803: PROMPT BVRcIc Observations
  71. GRB 050730, optical observation
  72. GRB050805a : Null detection report
  73. GRB050803, optical observations
  74. Swift-BAT trigger 149118 is very likely not a GRB
  75. Retraction of Swift Trigger 149131 (GRB 050805B)
  76. GRB050805b: MASTER optical observations
  77. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  78. GRB050805a: MASTER optical candidat
  79. Swift-BAT trigger 149118 is probably not a GRB
  80. GRB050802: TNG optical observations
  81. GRB 050803: RTT150 optical observations
  82. GRB050730: Radio Detection
  83. GRB050803: CrAO optical observations, possible OT candidate
  84. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  85. GRB 050803: Keck Observations
  86. GRB 050802.422: Fading of the afterglow and detection of the host
  87. GRB050803: MASTER further analys
  88. GRB 050803, optical observations
  89. GRB 050803: Magellan Observations
  90. GRB 050803: early Swift XRT analysis results
  91. GRB050803: MASTER optical observations
  92. GRB050802: Tentative absorption redshift
  93. GRB050803: Swift-BAT detection of a very long burst
  94. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  95. GRB 050802: Swift/UVOT optical and UV detections
  96. GRB050801: Unchanged decay slope
  97. GRB050802 radio non-detection
  98. GRB 050730: OHP optical observations
  99. GRB 050802: early Swift XRT analysis results
  100. GRB 050802: Swift/UVOT observations

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