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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. GRB 050824: XRT refined analysis and possible afterglow detection
  2. GRB 050824: BAT refined analysis of a soft weak burst
  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. GRB 050824 optical candidate
  9. GRB050820A: RTT150 optical observations
  10. GRB050820a: PROMPT RcIc Observations
  11. GRB050815: Maidanak optical observation
  12. XRF050509c: Radio upper limits from GMRT
  13. VLT/UVES spectroscopy of GRB050820
  14. GRB050822: Swift/UVOT upper limits
  15. GRB 050820A BAT observations of second, larger episode of emission
  16. GRB050813: Maidanak I-band observations
  17. GRB 050822: Swift-BAT refined analysis
  18. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  19. GRB050820B at FRAM
  20. GRB050820A: RTT150 optical observations
  21. GRB 050820a - corrections to GCN 3846
  22. Swift/UVOT UV Photometry of GRB 050820B
  23. GRB 050822: ROTSE-III Prompt Optical Limits
  24. GRB 050822: Swift detection of a long burst
  25. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  26. GRB050820A: Radio Observation
  27. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  28. GRB050820a BVRcIc field photometry
  29. GRB050820B XMM-Newton observation
  30. GRB 050820a: NIR Observations by WIRO
  31. GRB 050820B: Swift XRT position
  32. GRB050820B: Planned XMM-Newton observation
  33. GRB050820B: Refined analysis of the Swift-BAT burst
  34. GRB050820B: BAT-Swift detection of a bright GRB
  35. Swift/UVOT photometry of GRB050820
  36. GRB050820: refined XRT analysis
  37. GRB 050820: Early RAPTOR detections
  38. GRB 050820 Swift-BAT refined analysis
  39. GRB 050820: P60 Temporal Decay Index
  40. GRB 050820: High Resolution Spectroscopy from Keck
  41. GRB050819: refined XRT analysis
  42. GRB050819: RTT150 optical observations
  43. GRB 050820: Swift detection of a GRB
  44. GRB050820: Optical afterglow from P60
  45. GRB 050819 Swift-BAT refined analysis
  46. GRB050819: Swift XRT position
  47. GRB050819: Swift-BAT detection of a weak burst
  48. Swift-BAT trigger 150993 is not a GRB
  49. Swift Trigger 150823 is HETE J1900.1-2455
  50. GRB 050817: Optical observations
  51. GRB 050815: Radio Observation
  52. GRB050814: Radio Observation
  53. GRB050817: Negative Optical Observations
  54. GRB050817: Swift-BAT Detection of a burst
  55. GRB 050814: continued fading
  56. GRB050815: Optical afterglow detection by Swift UVOT
  57. GRB050815: XRT refined analysis
  58. GRB 050813: Radio Observations
  59. GRB050815: Refined analysis of the Swift-BAT burst
  60. GRB 050815: ROTSE-III Optical Limits
  61. GRB050815: Swift XRT afterglow localization
  62. GRB050815: Swift-BAT detection of a burst
  63. GRB 050730: Third Epoch WSRT Radio Observations
  64. GRB050814: Fading red source
  65. GRB 050813: Gemini Spectra Revisited
  66. GRB050814: P60 Optical Afterglow Candidate
  67. GRB 050813: Non-fading of afterglow candidate
  68. GRB 050814: XRT refined analysis
  69. GRB050814: SWIFT/UVOT observation
  70. GRB050814: Refined analysis of the Swift-BAT burst
  71. GRB050813: Gemini Imaging
  72. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  73. GRB 050814: Swift XRT Afterglow Localization
  74. GRB 050814: Swift detection of a burst
  75. GRB 050813: Magellan detection of a high redshift galaxy cluster
  76. GRB050813: RTT150 optical observations
  77. GRB 050813: I-band observations
  78. GRB050813, SDSS pre-burst observations
  79. GRB 050813: KAIT optical limit
  80. GRB 050813: Swift-BAT refined analysis
  81. GRB 050813: Photometry of object in XRT error circle
  82. GRB050813: SWIFT/UVOT observation
  83. GRB 050813: Swift XRT afterglow localization
  84. RBO GRB 050714A and GRB 050716 observations
  85. GRB 050813: Possible Short Swift-BAT GRB
  86. GRB050813 (Swift 150139): P60 Observations
  87. Swift-BAT trigger 150131 is not a GRB
  88. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  89. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  90. GRB050803: CrAO optical observations, no OT candidate
  91. Detection of an intermediate burst from SGR 1806-20 on August 8
  92. GRB 050730: WSRT Radio Observations
  93. GRB 050803: PROMPT BVRcIc Observations
  94. GRB 050807: ROTSE-III Optical Limits
  95. GRB 050730, optical observation
  96. GRB050805b: CrAO optical limit
  97. GRB050805a : Null detection report
  98. GRB050730, optical observations
  99. GRB050803, optical observations
  100. Swift-BAT trigger 149118 is very likely not a GRB

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