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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"

36156 results found.

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

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