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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"
  1. GRB050824: First 2 hours of power low optical decay?
  2. GRB 050826: Swift XRT position
  3. GRB050826: Swift-BAT detection of a long burst
  4. GRB050824: MASTER final analysis of the OT observations
  5. Possible GRB050825:MASTER optical observations
  6. Swift-BAT trigger 152038 is definitely not a GRB
  7. GRB050824: CORRECTION to UVOT observing times
  8. Swift-BAT trigger 152038 is probably not a GRB
  9. GRB050824: Swift/UVOT detection of fading afterglow
  10. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  11. GRB050824, I-band imaging
  12. GRB050824: Radio Observations
  13. GRB 050824: Spectroscopic redshift from the VLT
  14. GRB 050822: refined XRT analysis
  15. GRB 050824: XRT refined analysis and possible afterglow detection
  16. GRB 050824: BAT refined analysis of a soft weak burst
  17. GRB050824: MASTER:OT decay
  18. GRB050824: MASTER observation OT
  19. GRB050805a: MASTER optical candidat
  20. GRB 050824: ROTSE-III Optical Limits
  21. GRB050824: Swift-BAT detection of a burst
  22. GRB 050824 optical candidate
  23. GRB050820A: RTT150 optical observations
  24. GRB050820a: PROMPT RcIc Observations
  25. GRB050815: Maidanak optical observation
  26. XRF050509c: Radio upper limits from GMRT
  27. VLT/UVES spectroscopy of GRB050820
  28. GRB050822: Swift/UVOT upper limits
  29. GRB 050820A BAT observations of second, larger episode of emission
  30. GRB050813: Maidanak I-band observations
  31. GRB 050822: Swift-BAT refined analysis
  32. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  33. GRB050820B at FRAM
  34. GRB050820A: RTT150 optical observations
  35. GRB 050820a - corrections to GCN 3846
  36. Swift/UVOT UV Photometry of GRB 050820B
  37. GRB 050822: ROTSE-III Prompt Optical Limits
  38. GRB 050822: Swift detection of a long burst
  39. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  40. GRB050820A: Radio Observation
  41. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  42. GRB050820a BVRcIc field photometry
  43. GRB050820B XMM-Newton observation
  44. GRB 050820a: NIR Observations by WIRO
  45. GRB 050820B: Swift XRT position
  46. GRB050820B: Planned XMM-Newton observation
  47. SUBJECT: GRB050820B: Refined analysis of the Swift-BAT burst
  48. GRB050820B: BAT-Swift detection of a bright GRB
  49. Swift/UVOT photometry of GRB050820
  50. GRB050820: refined XRT analysis
  51. GRB 050820: Early RAPTOR detections
  52. GRB 050820 Swift-BAT refined analysis
  53. GRB 050820: P60 Temporal Decay Index
  54. GRB 050820: High Resolution Spectroscopy from Keck
  55. GRB050819: refined XRT analysis
  56. GRB050819: RTT150 optical observations
  57. GRB 050820: Swift detection of a GRB
  58. GRB050820: Optical afterglow from P60
  59. GRB 050819 Swift-BAT refined analysis
  60. GRB050819: Swift XRT position
  61. GRB050819: Swift-BAT detection of a weak burst
  62. Swift-BAT trigger 150993 is not a GRB
  63. Swift Trigger 150823 is HETE J1900.1-2455
  64. GRB 050817: Optical observations
  65. GRB 050815: Radio Observation
  66. GRB050814: Radio Observation
  67. GRB050817: Negative Optical Observations
  68. GRB050817: Swift-BAT Detection of a burst
  69. GRB 050814: continued fading
  70. GRB050815: Optical afterglow detection by Swift UVOT
  71. GRB050815: XRT refined analysis
  72. GRB 050813: Radio Observations
  73. GRB050815: Refined analysis of the Swift-BAT burst
  74. GRB 050815: ROTSE-III Optical Limits
  75. GRB050815: Swift XRT afterglow localization
  76. GRB050815: Swift-BAT detection of a burst
  77. GRB 050730: Third Epoch WSRT Radio Observations
  78. GRB050814: Fading red source
  79. GRB 050813: Gemini Spectra Revisited
  80. GRB050814: P60 Optical Afterglow Candidate
  81. GRB 050813: Non-fading of afterglow candidate
  82. GRB 050814: XRT refined analysis
  83. GRB050814: SWIFT/UVOT observation
  84. GRB050814: Refined analysis of the Swift-BAT burst
  85. GRB050813: Gemini Imaging
  86. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  87. GRB 050814: Swift XRT Afterglow Localization
  88. GRB 050814: Swift detection of a burst
  89. GRB 050813: Magellan detection of a high redshift galaxy cluster
  90. GRB050813: RTT150 optical observations
  91. GRB 050813: I-band observations
  92. GRB050813, SDSS pre-burst observations
  93. GRB 050813: KAIT optical limit
  94. GRB 050813: Swift-BAT refined analysis
  95. GRB 050813: Photometry of object in XRT error circle
  96. GRB050813: SWIFT/UVOT observation
  97. GRB 050813: Swift XRT afterglow localization
  98. RBO GRB 050714A and GRB 050716 observations
  99. GRB 050813: Possible Short Swift-BAT GRB
  100. GRB050813 (Swift 150139): P60 Observations

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