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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"

45467 results found.

  1. GRB 050814: continued fading
  2. GRB050815: Optical afterglow detection by Swift UVOT
  3. GRB050815: XRT refined analysis
  4. GRB 050813: Radio Observations
  5. GRB050815: Refined analysis of the Swift-BAT burst
  6. GRB 050815: ROTSE-III Optical Limits
  7. GRB050815: Swift XRT afterglow localization
  8. GRB050815: Swift-BAT detection of a burst
  9. GRB 050730: Third Epoch WSRT Radio Observations
  10. GRB050814: Fading red source
  11. GRB 050813: Gemini Spectra Revisited
  12. GRB050814: P60 Optical Afterglow Candidate
  13. GRB 050813: Non-fading of afterglow candidate
  14. GRB 050814: XRT refined analysis
  15. GRB050814: SWIFT/UVOT observation
  16. GRB050814: Refined analysis of the Swift-BAT burst
  17. GRB050813: Gemini Imaging
  18. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  19. GRB 050814: Swift XRT Afterglow Localization
  20. GRB 050814: Swift detection of a burst
  21. GRB 050813: Magellan detection of a high redshift galaxy cluster
  22. GRB050813: RTT150 optical observations
  23. GRB 050813: I-band observations
  24. GRB050813, SDSS pre-burst observations
  25. GRB 050813: KAIT optical limit
  26. GRB 050813: Swift-BAT refined analysis
  27. GRB 050813: Photometry of object in XRT error circle
  28. GRB050813: SWIFT/UVOT observation
  29. GRB 050813: Swift XRT afterglow localization
  30. RBO GRB 050714A and GRB 050716 observations
  31. GRB 050813: Possible Short Swift-BAT GRB
  32. GRB050813 (Swift 150139): P60 Observations
  33. Swift-BAT trigger 150131 is not a GRB
  34. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  35. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  36. GRB050803: CrAO optical observations, no OT candidate
  37. Detection of an intermediate burst from SGR 1806-20 on August 8
  38. GRB 050730: WSRT Radio Observations
  39. GRB 050803: PROMPT BVRcIc Observations
  40. GRB 050807: ROTSE-III Optical Limits
  41. GRB 050730, optical observation
  42. GRB050805b: CrAO optical limit
  43. GRB050805a : Null detection report
  44. GRB050730, optical observations
  45. GRB050803, optical observations
  46. Swift-BAT trigger 149118 is very likely not a GRB
  47. Retraction of Swift Trigger 149131 (GRB 050805B)
  48. GRB 050805b: OHP optical limits
  49. GRB 050805b: TAROT optical limits
  50. GRB050805b: MASTER optical observations
  51. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  52. GRB050805a: MASTER optical candidat
  53. Swift-BAT trigger 149118 is probably not a GRB
  54. GRB050802: TNG optical observations
  55. GRB050803: Radio Observation
  56. GRB 050803: RTT150 optical observations
  57. GRB050801: Radio Observation
  58. GRB050730: Radio Detection
  59. GRB050803: CrAO optical observations, possible OT candidate
  60. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  61. GRB 050803: Keck Observations
  62. GRB 050803: Swift-BAT refined analysis
  63. GRB 050802.422: Fading of the afterglow and detection of the host
  64. GRB050803: MASTER further analys
  65. GRB 050803, optical observations
  66. GRB 050803: Magellan Observations
  67. GRB 050803: early Swift XRT analysis results
  68. GRB 050803: TAROT optical limits
  69. GRB050803: MASTER optical observations
  70. GRB050802: Tentative absorption redshift
  71. GRB050803: Swift-BAT detection of a very long burst
  72. GCN GRB observation 050713A
  73. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  74. GRB 050802: Swift/UVOT optical and UV detections
  75. GRB050802: CrAO optical observations
  76. GRB050801: Unchanged decay slope
  77. GRB050802 radio non-detection
  78. GRB 050730: OHP optical observations
  79. GRB 050802: early Swift XRT analysis results
  80. GRB 050802: Swift/UVOT observations
  81. GRB 050802 : Lulin Optical follow-up observation
  82. GRB 050802: Swift-BAT refined analysis
  83. GRB050801: Optical photometry and decay index
  84. GRB 050802: XRT position
  85. GRB 050802: Swift Gamma-ray Burst
  86. GRB050801: Swift/UVOT Optical and UV detections
  87. GRB 050730: Preliminary Analysis of MIKE Spectrum
  88. GCN 050801: early Swift XRT analysis results
  89. GRB 050801: Swift-BAT refined analysis
  90. GRB 050801, SMARTS optical/IR afterglow observations
  91. GRB 050801, afterglow observations
  92. GRB 050730, corrected photometry and break?
  93. GRB 050801: ROTSE-III Early Afterglow Break
  94. GRB050801: Swift-BAT detection of a burst
  95. GRB 050801: ROTSE-III Detection of Possible Counterpart
  96. GRB 050730: XRT refined analysis
  97. Correction to GCN Circ 3476 on GRB050525A
  98. GRB 050730: early TAROT optical observations
  99. GRB 050726: PROMPT Rc Observations
  100. GRB 050730: RTT150 optical observations

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