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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"

36157 results found.

  1. GRB 050626 - a long GRB detected with INTEGRAL
  2. GRB 050525A: Swift Late-Time Decay Rate
  3. H3804: A Possible New XRB Detected by HETE
  4. XRF 050509c: Optical monitoring
  5. IBAS Alert #2512 is NOT a GRB
  6. GRB 050416(a): Host Galaxy Redshift Determination
  7. GRB 050607: MDM Observation
  8. GRB 050607 optical decay
  9. GRB 050607: RTT150 optical observations
  10. GRB 050607 : Lulin R-band observation
  11. GRB 050607: PROMPT VRcIc Observations
  12. GRB 050607: RAPTOR-S Early Optical Limits
  13. GRB 050525a, Mid-Infrared Observations
  14. GRB 050607: Optical decay and spectral slope
  15. GRB 050607: MDM Observations
  16. GRB050607,optical observation
  17. GRB 050607 - XRT refined data analysis
  18. Optical Afterglow of GRB 050607
  19. GRB050607 optical limit by "Pi of the Sky"
  20. GRB050607: Swift Detection of a long GRB
  21. GRB050607: P60 Observations
  22. GRB 050603: prediction of t_break
  23. Limits on a SN in the field of GRB 050509b
  24. GRB 050603: Redshift
  25. GRB 050603 - XRT data analysis of the first day
  26. Konus-Wind observation of GRB 050603
  27. GRB 050603: Analysis of UVOT data
  28. GRB 050603: Swift XRT Position
  29. GRB050603: Radio Detection
  30. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  31. GRB 050603: Afterglow Identification from LCO
  32. GRB 050603: INTEGRAL shows it is not a short GRB
  33. GRB 050408: jet break in the XRT light curve
  34. GRB 050525a, infrared observations
  35. GRB 050525a, SMARTS optical/IR afterglow observations
  36. Correction to GCN Circ 3502 on GRB 050528
  37. GRB050528: updated Liverpool Telescope limits
  38. Swift-BAT GRB 050528: a soft burst
  39. Update on Swift-BAT GRB 050528 (Trigger 130679)
  40. GRB050528: BOOTES optical candidate (retraction)
  41. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  42. GRB050528: BOOTES optical candidate
  43. Possible GRB050528: no candidate from Liverpool Telescope
  44. Swift-BAT detection of possible GRB 050528
  45. GRB050525a: Radio Observations
  46. GRB 050509b: refined XRT/Chandra afterglow position analysis
  47. GRB 050525: RTT150, Optical observations
  48. GRB050525a: optical upper limits
  49. GRB 050525a: SARA Observations
  50. GRB 050525B: Swift-BAT observations
  51. GRB 050525: MITSuME Optical Observation in VRI
  52. GRB 050525a: MDM Observations
  53. GRB050525A,optical observation
  54. GRB 050525 : Lulin optical afterglow observations
  55. GRB050525: Super-LOTIS observations
  56. GRB 050525, spectral lag pseudo-redshift
  57. GRB 050525a: Gemini/GMOS Spectra
  58. GRB050306: optical afterglow not confirmed
  59. GRB 050525: BART optical observation
  60. GRB 050525A: BOOTES simultaneous optical observations
  61. GRB 050525A: Swift-BAT refined analysis
  62. GRB050525: Optical observations
  63. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  64. GRB 050525: pseudo-redshift
  65. Swift/UVOT UV and optical detections of GRB 050525
  66. Konus-Wind observation of GRB 050525
  67. GRB 050525: TAROT observations of the early afterglow
  68. INTEGRAL detection of GRB 050525
  69. GRB 050525, infrared observations
  70. GRB 050525: Optical observation
  71. GRB 050525: observatons of the optical afterglow
  72. GRB050525: ROTSE-III Refined Analysis
  73. GRB 050525 - Very Bright, Not Short
  74. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  75. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  76. XRF050522: NIR observations of XRT candidate
  77. XRF050522: Radio Observations
  78. GRB 050509A: Further I-band imaging
  79. GRB050522,optical observation
  80. GRB050520,optical observation
  81. XRF 050522: Continued NIR P200 Monitoring
  82. RBO Observations of GRB050522
  83. GRB050509b: optical observations
  84. Recent GRB BVRcIc field photometry
  85. GRB050520: Radio Observations
  86. XRF050522, BVRcIc field photometry
  87. XRF050522: Optical Observations
  88. XRF 050522: KAIT observations
  89. XRF 050522 detected with INTEGRAL
  90. GRB 050520: VLT/ULTRACAM observations
  91. Swift UVOT Observations of GRB 050520
  92. GRB 050520: Swift XRT refined analysis
  93. RBO Observations of GRB050520
  94. GRB 050520: P200 Observations
  95. GRB050520: Liverpool Telescope follow-up
  96. GRB 050520: TAROT optical limit
  97. GRB 050520: Swift XRT position
  98. GRB 050520: VLT/ULTRACAM observations
  99. GRB 050520: OSN optical observations
  100. GRB 050520: BART optical limit

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