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

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