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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"

35948 results found.

  1. XRF 050509c: Optical monitoring
  2. IBAS Alert #2512 is NOT a GRB
  3. GRB 050416(a): Host Galaxy Redshift Determination
  4. GRB 050607: MDM Observation
  5. GRB 050607 optical decay
  6. GRB 050607: RTT150 optical observations
  7. GRB 050607 : Lulin R-band observation
  8. GRB 050607: PROMPT VRcIc Observations
  9. GRB 050607: RAPTOR-S Early Optical Limits
  10. GRB 050525a, Mid-Infrared Observations
  11. GRB 050607: Optical decay and spectral slope
  12. GRB 050607: MDM Observations
  13. GRB050607,optical observation
  14. GRB 050607 - XRT refined data analysis
  15. Optical Afterglow of GRB 050607
  16. GRB050607 optical limit by "Pi of the Sky"
  17. GRB050607: Swift Detection of a long GRB
  18. GRB050607: P60 Observations
  19. GRB 050603: prediction of t_break
  20. Limits on a SN in the field of GRB 050509b
  21. GRB 050603: Redshift
  22. GRB 050603 - XRT data analysis of the first day
  23. Konus-Wind observation of GRB 050603
  24. GRB 050603: Analysis of UVOT data
  25. GRB 050603: Swift XRT Position
  26. GRB050603: Radio Detection
  27. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  28. GRB 050603: Afterglow Identification from LCO
  29. GRB 050603: INTEGRAL shows it is not a short GRB
  30. GRB 050408: jet break in the XRT light curve
  31. GRB 050525a, infrared observations
  32. GRB 050525a, SMARTS optical/IR afterglow observations
  33. Correction to GCN Circ 3502 on GRB 050528
  34. GRB050528: updated Liverpool Telescope limits
  35. Swift-BAT GRB 050528: a soft burst
  36. Update on Swift-BAT GRB 050528 (Trigger 130679)
  37. GRB050528: BOOTES optical candidate (retraction)
  38. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  39. GRB050528: BOOTES optical candidate
  40. Possible GRB050528: no candidate from Liverpool Telescope
  41. Swift-BAT detection of possible GRB 050528
  42. GRB050525a: Radio Observations
  43. GRB 050509b: refined XRT/Chandra afterglow position analysis
  44. GRB 050525: RTT150, Optical observations
  45. GRB050525a: optical upper limits
  46. GRB 050525a: SARA Observations
  47. GRB 050525B: Swift-BAT observations
  48. GRB 050525: MITSuME Optical Observation in VRI
  49. GRB 050525a: MDM Observations
  50. GRB050525A,optical observation
  51. GRB 050525 : Lulin optical afterglow observations
  52. GRB050525: Super-LOTIS observations
  53. GRB 050525, spectral lag pseudo-redshift
  54. GRB 050525a: Gemini/GMOS Spectra
  55. GRB050306: optical afterglow not confirmed
  56. GRB 050525: BART optical observation
  57. GRB 050525A: BOOTES simultaneous optical observations
  58. GRB 050525A: Swift-BAT refined analysis
  59. GRB050525: Optical observations
  60. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  61. GRB 050525: pseudo-redshift
  62. Swift/UVOT UV and optical detections of GRB 050525
  63. Konus-Wind observation of GRB 050525
  64. GRB 050525: TAROT observations of the early afterglow
  65. INTEGRAL detection of GRB 050525
  66. GRB 050525, infrared observations
  67. GRB 050525: Optical observation
  68. GRB 050525: observatons of the optical afterglow
  69. GRB050525: ROTSE-III Refined Analysis
  70. GRB 050525 - Very Bright, Not Short
  71. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  72. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  73. XRF050522: NIR observations of XRT candidate
  74. XRF050522: Radio Observations
  75. GRB 050509A: Further I-band imaging
  76. GRB050522,optical observation
  77. GRB050520,optical observation
  78. XRF 050522: Continued NIR P200 Monitoring
  79. RBO Observations of GRB050522
  80. GRB050509b: optical observations
  81. Recent GRB BVRcIc field photometry
  82. GRB050520: Radio Observations
  83. XRF050522, BVRcIc field photometry
  84. XRF050522: Optical Observations
  85. XRF 050522: KAIT observations
  86. XRF 050522 detected with INTEGRAL
  87. GRB 050520: VLT/ULTRACAM observations
  88. Swift UVOT Observations of GRB 050520
  89. GRB 050520: Swift XRT refined analysis
  90. RBO Observations of GRB050520
  91. GRB 050520: P200 Observations
  92. GRB050520: Liverpool Telescope follow-up
  93. GRB 050520: TAROT optical limit
  94. GRB 050520: Swift XRT position
  95. GRB 050520: VLT/ULTRACAM observations
  96. GRB 050520: OSN optical observations
  97. GRB 050520: BART optical limit
  98. GRB 050520 - A long GRB detected with INTEGRAL
  99. Swift-BAT trigger 122203 is not a real GRB
  100. GRB 050504: Swift XRT afterglow candidate has faded

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