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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"

45463 results found.

  1. GRB 050904: Possible High-Redshift GRB
  2. GRB 050904: SOAR/PROMPT Observations
  3. GRB050904: P60 Observations
  4. GRB 050904: TAROT optical limits
  5. GRB050904: Swift-BAT detection of a probable burst
  6. Swift-BAT triggers 153461-153465 are not GRBs
  7. Retraction of Swift-BAT trigger #153355
  8. GRB 050824: MDM Observations
  9. GRB 050827: Swift XRT preliminary analysis results
  10. IBAS Alerts 2641 and 2642: not a real GRB
  11. Swift Trigger #152652 is not a GRB
  12. GRB 050827 : OSN 1.5m optical observations
  13. GRB 050827: P200 NIR Observations
  14. GRB050827: Swift/UVOT upper limits
  15. GRB 050827: Optical Limit
  16. GRB 050827: XRT possible afterglow detection
  17. GRB 050826 : Lulin R band observation
  18. GRB050824: Maidanak optical limits
  19. GRB050820A: RTT150 optical observations
  20. GRB050827: RTT150 optical observations
  21. GRB 050827: Swift-BAT refined analysis
  22. GRB050827: Swift-BAT detection of a burst
  23. Subaru Observations of GRB050724
  24. GRB 050826: Optical Candidate
  25. GRB050824, HETE-2 Observation
  26. GRB 050826: Swift XRT preliminary analysis results
  27. GRB 050826: BAT refined analysis
  28. GRB050826: Swift/UVOT early upper limits
  29. GRB050824: First 2 hours of power low optical decay?
  30. GRB 050826: Swift XRT position
  31. GRB050826: Swift-BAT detection of a long burst
  32. GRB050824: MASTER final analysis of the OT observations
  33. Possible GRB050825:MASTER optical observations
  34. Swift-BAT trigger 152038 is definitely not a GRB
  35. GRB050824: CORRECTION to UVOT observing times
  36. Swift-BAT trigger 152038 is probably not a GRB
  37. GRB050824: Swift/UVOT detection of fading afterglow
  38. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  39. GRB050824, I-band imaging
  40. GRB050824: Radio Observations
  41. GRB 050824: Spectroscopic redshift from the VLT
  42. GRB 050822: refined XRT analysis
  43. GRB 050824: XRT refined analysis and possible afterglow detection
  44. GRB 050824: BAT refined analysis of a soft weak burst
  45. GRB050824: MASTER:OT decay
  46. GRB050824: MASTER observation OT
  47. GRB050805a: MASTER optical candidat
  48. GRB 050824: ROTSE-III Optical Limits
  49. GRB050824: Swift-BAT detection of a burst
  50. GRB 050824 optical candidate
  51. GRB050820A: RTT150 optical observations
  52. GRB050820a: PROMPT RcIc Observations
  53. GRB050815: Maidanak optical observation
  54. XRF050509c: Radio upper limits from GMRT
  55. VLT/UVES spectroscopy of GRB050820
  56. GRB050822: Swift/UVOT upper limits
  57. GRB 050820A BAT observations of second, larger episode of emission
  58. GRB050813: Maidanak I-band observations
  59. GRB 050822: Swift-BAT refined analysis
  60. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  61. GRB050820B at FRAM
  62. GRB050820A: RTT150 optical observations
  63. GRB 050820a - corrections to GCN 3846
  64. Swift/UVOT UV Photometry of GRB 050820B
  65. GRB 050822: ROTSE-III Prompt Optical Limits
  66. GRB 050822: Swift detection of a long burst
  67. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  68. GRB050820A: Radio Observation
  69. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  70. GRB050820a BVRcIc field photometry
  71. GRB050820B XMM-Newton observation
  72. GRB 050820a: NIR Observations by WIRO
  73. GRB 050820B: Swift XRT position
  74. GRB050820B: Planned XMM-Newton observation
  75. GRB050820B: Refined analysis of the Swift-BAT burst
  76. GRB050820B: BAT-Swift detection of a bright GRB
  77. Swift/UVOT photometry of GRB050820
  78. GRB050820: refined XRT analysis
  79. GRB 050820: Early RAPTOR detections
  80. GRB 050820 Swift-BAT refined analysis
  81. GRB 050820: P60 Temporal Decay Index
  82. GRB 050820: High Resolution Spectroscopy from Keck
  83. GRB050819: refined XRT analysis
  84. GRB050819: RTT150 optical observations
  85. GRB 050820: Swift detection of a GRB
  86. GRB050820: Optical afterglow from P60
  87. GRB 050819 Swift-BAT refined analysis
  88. GRB050819: Swift XRT position
  89. GRB050819: Swift-BAT detection of a weak burst
  90. Swift-BAT trigger 150993 is not a GRB
  91. Swift Trigger 150823 is HETE J1900.1-2455
  92. GRB 050817: Optical observations
  93. GRB 050815: Radio Observation
  94. GRB050814: Radio Observation
  95. GRB050817: Negative Optical Observations
  96. GRB050817: Swift-BAT Detection of a burst
  97. GRB 050814: continued fading
  98. GRB050815: Optical afterglow detection by Swift UVOT
  99. GRB050815: XRT refined analysis
  100. GRB 050813: Radio Observations

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