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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. GRB050814: Refined analysis of the Swift-BAT burst
  2. GRB050813: Gemini Imaging
  3. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  4. GRB 050814: Swift XRT Afterglow Localization
  5. GRB 050814: Swift detection of a burst
  6. GRB 050813: Magellan detection of a high redshift galaxy cluster
  7. GRB050813: RTT150 optical observations
  8. GRB 050813: I-band observations
  9. GRB050813, SDSS pre-burst observations
  10. GRB 050813: KAIT optical limit
  11. GRB 050813: Swift-BAT refined analysis
  12. GRB 050813: Photometry of object in XRT error circle
  13. GRB050813: SWIFT/UVOT observation
  14. GRB 050813: Swift XRT afterglow localization
  15. RBO GRB 050714A and GRB 050716 observations
  16. GRB 050813: Possible Short Swift-BAT GRB
  17. GRB050813 (Swift 150139): P60 Observations
  18. Swift-BAT trigger 150131 is not a GRB
  19. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  20. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  21. GRB050803: CrAO optical observations, no OT candidate
  22. Detection of an intermediate burst from SGR 1806-20 on August 8
  23. GRB 050730: WSRT Radio Observations
  24. GRB 050803: PROMPT BVRcIc Observations
  25. GRB 050807: ROTSE-III Optical Limits
  26. GRB 050730, optical observation
  27. GRB050805b: CrAO optical limit
  28. GRB050805a : Null detection report
  29. GRB050730, optical observations
  30. GRB050803, optical observations
  31. Swift-BAT trigger 149118 is very likely not a GRB
  32. Retraction of Swift Trigger 149131 (GRB 050805B)
  33. GRB 050805b: OHP optical limits
  34. GRB 050805b: TAROT optical limits
  35. GRB050805b: MASTER optical observations
  36. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  37. GRB050805a: MASTER optical candidat
  38. Swift-BAT trigger 149118 is probably not a GRB
  39. GRB050802: TNG optical observations
  40. GRB050803: Radio Observation
  41. GRB 050803: RTT150 optical observations
  42. GRB050801: Radio Observation
  43. GRB050730: Radio Detection
  44. GRB050803: CrAO optical observations, possible OT candidate
  45. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  46. GRB 050803: Keck Observations
  47. GRB 050803: Swift-BAT refined analysis
  48. GRB 050802.422: Fading of the afterglow and detection of the host
  49. GRB050803: MASTER further analys
  50. GRB 050803, optical observations
  51. GRB 050803: Magellan Observations
  52. GRB 050803: early Swift XRT analysis results
  53. GRB 050803: TAROT optical limits
  54. GRB050803: MASTER optical observations
  55. GRB050802: Tentative absorption redshift
  56. GRB050803: Swift-BAT detection of a very long burst
  57. GCN GRB observation 050713A
  58. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  59. GRB 050802: Swift/UVOT optical and UV detections
  60. GRB050802: CrAO optical observations
  61. GRB050801: Unchanged decay slope
  62. GRB050802 radio non-detection
  63. GRB 050730: OHP optical observations
  64. GRB 050802: early Swift XRT analysis results
  65. GRB 050802: Swift/UVOT observations
  66. GRB 050802 : Lulin Optical follow-up observation
  67. GRB 050802: Swift-BAT refined analysis
  68. GRB050801: Optical photometry and decay index
  69. GRB 050802: XRT position
  70. GRB 050802: Swift Gamma-ray Burst
  71. GRB050801: Swift/UVOT Optical and UV detections
  72. GRB 050730: Preliminary Analysis of MIKE Spectrum
  73. GCN 050801: early Swift XRT analysis results
  74. GRB 050801: Swift-BAT refined analysis
  75. GRB 050801, SMARTS optical/IR afterglow observations
  76. GRB 050801, afterglow observations
  77. GRB 050730, corrected photometry and break?
  78. GRB 050801: ROTSE-III Early Afterglow Break
  79. GRB050801: Swift-BAT detection of a burst
  80. GRB050801: GCN XRT position is incorrect
  81. GRB 050801: ROTSE-III Detection of Possible Counterpart
  82. GRB 050730: XRT refined analysis
  83. Correction to GCN Circ 3476 on GRB050525A
  84. GRB 050730: early TAROT optical observations
  85. GRB 050726: PROMPT Rc Observations
  86. GRB 050730: RTT150 optical observations
  87. Swift/UVOT photometry of GRB050730
  88. GRB 050730, spectra and optical photometry
  89. GRB050730: Refined BAT analysis of the Swift-BAT burst
  90. GRB 050730: Swift XRT afterglow observations
  91. GRB 050730 XMM-Newton observation
  92. GRB 050730: PROMPT VRcIc Observations
  93. GRB050730, afterglow observations
  94. GRB050730: confirmation of redshift
  95. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  96. GRB 050730, SMARTS optical/IR afterglow observations
  97. GRB 050730 : Planned XMM-Newton observation
  98. GRB050730: Liverpool Telescope optical observations
  99. GRB 050730, optical candidate
  100. GRB050730: Swift-BAT detection of a weak burst

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