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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"

33874 results found.

  1. GRB 050904: BAT refined analysis of partial data set
  2. GRB 050904: TAROT optical measurements
  3. GRB050904: Optical Observations
  4. GRB 050904: Environmental Constraints
  5. GRB 050904: Possible High-Redshift GRB
  6. GRB 050904: SOAR/PROMPT Observations
  7. GRB 050904: TAROT optical limits
  8. Swift-BAT triggers 153461-153465 are not GRBs
  9. GRB 050824: MDM Observations
  10. GRB 050827: Swift XRT preliminary analysis results
  11. IBAS Alerts 2641 and 2642: not a real GRB
  12. Swift Trigger #152652 is not a GRB
  13. GRB 050827 : OSN 1.5m optical observations
  14. GRB 050827: P200 NIR Observations
  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. GRB 050826: Optical Candidate
  23. GRB050824, HETE-2 Observation
  24. GRB 050826: Swift XRT preliminary analysis results
  25. GRB 050826: BAT refined analysis
  26. GRB050824: First 2 hours of power low optical decay?
  27. GRB 050826: Swift XRT position
  28. GRB050826: Swift-BAT detection of a long burst
  29. GRB050824: MASTER final analysis of the OT observations
  30. Possible GRB050825:MASTER optical observations
  31. Swift-BAT trigger 152038 is definitely not a GRB
  32. Swift-BAT trigger 152038 is probably not a GRB
  33. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  34. GRB050824, I-band imaging
  35. GRB050824: Radio Observations
  36. GRB 050824: Spectroscopic redshift from the VLT
  37. GRB 050822: refined XRT analysis
  38. GRB 050824: XRT refined analysis and possible afterglow detection
  39. GRB 050824: BAT refined analysis of a soft weak burst
  40. GRB050824: MASTER:OT decay
  41. GRB050824: MASTER observation OT
  42. GRB050805a: MASTER optical candidat
  43. GRB 050824: ROTSE-III Optical Limits
  44. GRB050824: Swift-BAT detection of a burst
  45. GRB 050824 optical candidate
  46. GRB050820A: RTT150 optical observations
  47. GRB050820a: PROMPT RcIc Observations
  48. GRB050815: Maidanak optical observation
  49. XRF050509c: Radio upper limits from GMRT
  50. VLT/UVES spectroscopy of GRB050820
  51. GRB 050820A BAT observations of second, larger episode of emission
  52. GRB050813: Maidanak I-band observations
  53. GRB 050822: Swift-BAT refined analysis
  54. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  55. GRB050820B at FRAM
  56. GRB050820A: RTT150 optical observations
  57. GRB 050820a - corrections to GCN 3846
  58. Swift/UVOT UV Photometry of GRB 050820B
  59. GRB 050822: ROTSE-III Prompt Optical Limits
  60. GRB 050822: Swift detection of a long burst
  61. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  62. GRB050820A: Radio Observation
  63. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  64. GRB050820a BVRcIc field photometry
  65. GRB 050820a: NIR Observations by WIRO
  66. GRB 050820B: Swift XRT position
  67. GRB050820B: Refined analysis of the Swift-BAT burst
  68. GRB050820B: BAT-Swift detection of a bright GRB
  69. GRB050820: refined XRT analysis
  70. GRB 050820: Early RAPTOR detections
  71. GRB 050820 Swift-BAT refined analysis
  72. GRB 050820: P60 Temporal Decay Index
  73. GRB 050820: High Resolution Spectroscopy from Keck
  74. GRB050819: RTT150 optical observations
  75. GRB 050820: Swift detection of a GRB
  76. GRB 050819 Swift-BAT refined analysis
  77. GRB050819: Swift XRT position
  78. GRB050819: Swift-BAT detection of a weak burst
  79. Swift-BAT trigger 150993 is not a GRB
  80. Swift Trigger 150823 is HETE J1900.1-2455
  81. GRB 050817: Optical observations
  82. GRB 050815: Radio Observation
  83. GRB050814: Radio Observation
  84. GRB050817: Negative Optical Observations
  85. GRB 050814: continued fading
  86. GRB 050813: Radio Observations
  87. GRB050815: Refined analysis of the Swift-BAT burst
  88. GRB 050815: ROTSE-III Optical Limits
  89. GRB050815: Swift XRT afterglow localization
  90. GRB 050730: Third Epoch WSRT Radio Observations
  91. GRB050814: Fading red source
  92. GRB 050813: Gemini Spectra Revisited
  93. GRB 050813: Non-fading of afterglow candidate
  94. GRB 050814: XRT refined analysis
  95. GRB050814: Refined analysis of the Swift-BAT burst
  96. GRB050813: Gemini Imaging
  97. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  98. GRB 050814: Swift XRT Afterglow Localization
  99. GRB 050814: Swift detection of a burst
  100. GRB 050813: Magellan detection of a high redshift galaxy cluster

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