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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: CORRECTION to UVOT observing times
  2. Swift-BAT trigger 152038 is probably not a GRB
  3. GRB050824: Swift/UVOT detection of fading afterglow
  4. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  5. GRB050824, I-band imaging
  6. GRB050824: Radio Observations
  7. GRB 050824: Spectroscopic redshift from the VLT
  8. GRB 050822: refined XRT analysis
  9. GRB 050824: XRT refined analysis and possible afterglow detection
  10. GRB 050824: BAT refined analysis of a soft weak burst
  11. GRB050824: MASTER:OT decay
  12. GRB050824: MASTER observation OT
  13. GRB050805a: MASTER optical candidat
  14. GRB 050824: ROTSE-III Optical Limits
  15. GRB050824: Swift-BAT detection of a burst
  16. GRB 050824 optical candidate
  17. GRB050820A: RTT150 optical observations
  18. GRB050820a: PROMPT RcIc Observations
  19. GRB050815: Maidanak optical observation
  20. XRF050509c: Radio upper limits from GMRT
  21. VLT/UVES spectroscopy of GRB050820
  22. GRB050822: Swift/UVOT upper limits
  23. GRB 050820A BAT observations of second, larger episode of emission
  24. GRB050813: Maidanak I-band observations
  25. GRB 050822: Swift-BAT refined analysis
  26. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  27. GRB050820B at FRAM
  28. GRB050820A: RTT150 optical observations
  29. GRB 050820a - corrections to GCN 3846
  30. Swift/UVOT UV Photometry of GRB 050820B
  31. GRB 050822: ROTSE-III Prompt Optical Limits
  32. GRB 050822: Swift detection of a long burst
  33. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  34. GRB050820A: Radio Observation
  35. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  36. GRB050820a BVRcIc field photometry
  37. GRB050820B XMM-Newton observation
  38. GRB 050820a: NIR Observations by WIRO
  39. GRB 050820B: Swift XRT position
  40. GRB050820B: Planned XMM-Newton observation
  41. SUBJECT: GRB050820B: Refined analysis of the Swift-BAT burst
  42. GRB050820B: BAT-Swift detection of a bright GRB
  43. Swift/UVOT photometry of GRB050820
  44. GRB050820: refined XRT analysis
  45. GRB 050820: Early RAPTOR detections
  46. GRB 050820 Swift-BAT refined analysis
  47. GRB 050820: P60 Temporal Decay Index
  48. GRB 050820: High Resolution Spectroscopy from Keck
  49. GRB050819: refined XRT analysis
  50. GRB050819: RTT150 optical observations
  51. GRB 050820: Swift detection of a GRB
  52. GRB050820: Optical afterglow from P60
  53. GRB 050819 Swift-BAT refined analysis
  54. GRB050819: Swift XRT position
  55. GRB050819: Swift-BAT detection of a weak burst
  56. Swift-BAT trigger 150993 is not a GRB
  57. Swift Trigger 150823 is HETE J1900.1-2455
  58. GRB 050817: Optical observations
  59. GRB 050815: Radio Observation
  60. GRB050814: Radio Observation
  61. GRB050817: Negative Optical Observations
  62. GRB050817: Swift-BAT Detection of a burst
  63. GRB 050814: continued fading
  64. GRB050815: Optical afterglow detection by Swift UVOT
  65. GRB050815: XRT refined analysis
  66. GRB 050813: Radio Observations
  67. GRB050815: Refined analysis of the Swift-BAT burst
  68. GRB 050815: ROTSE-III Optical Limits
  69. GRB050815: Swift XRT afterglow localization
  70. GRB050815: Swift-BAT detection of a burst
  71. GRB 050730: Third Epoch WSRT Radio Observations
  72. GRB050814: Fading red source
  73. GRB 050813: Gemini Spectra Revisited
  74. GRB050814: P60 Optical Afterglow Candidate
  75. GRB 050813: Non-fading of afterglow candidate
  76. GRB 050814: XRT refined analysis
  77. GRB050814: SWIFT/UVOT observation
  78. GRB050814: Refined analysis of the Swift-BAT burst
  79. GRB050813: Gemini Imaging
  80. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  81. GRB 050814: Swift XRT Afterglow Localization
  82. GRB 050814: Swift detection of a burst
  83. GRB 050813: Magellan detection of a high redshift galaxy cluster
  84. GRB050813: RTT150 optical observations
  85. GRB 050813: I-band observations
  86. GRB050813, SDSS pre-burst observations
  87. GRB 050813: KAIT optical limit
  88. GRB 050813: Swift-BAT refined analysis
  89. GRB 050813: Photometry of object in XRT error circle
  90. GRB050813: SWIFT/UVOT observation
  91. GRB 050813: Swift XRT afterglow localization
  92. RBO GRB 050714A and GRB 050716 observations
  93. GRB 050813: Possible Short Swift-BAT GRB
  94. GRB050813 (Swift 150139): P60 Observations
  95. Swift-BAT trigger 150131 is not a GRB
  96. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  97. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  98. GRB050803: CrAO optical observations, no OT candidate
  99. Detection of an intermediate burst from SGR 1806-20 on August 8
  100. GRB 050730: WSRT Radio Observations

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