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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"

45653 results found.

  1. GRB 050701: Refined XRT analysis
  2. Swift UVOT observations of GRB 050701
  3. GRB050701: Swift-BAT Refined analysis
  4. GRB 050701: Swift XRT afterglow position
  5. Swift trigger 143708 is really GRB 050701
  6. GRB 050607, radio observations
  7. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  8. GRB 050626 - Correction to GCN 3552
  9. GRB 050626 - a long GRB detected with INTEGRAL
  10. GRB 050525A: Swift Late-Time Decay Rate
  11. GRB050525a: HST Observations
  12. CORRECTION: GRB050603 Swift UVOT Afterglow Observations
  13. H3804: A Possible New XRB Detected by HETE
  14. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  15. XRF 050509c: Optical monitoring
  16. Konus-Wind observation of an intermediate burst from SGR 1806-20
  17. IBAS Alert #2512 is NOT a GRB
  18. XRF050509c: Radio Detection
  19. GRB 050416(a): Host Galaxy Redshift Determination
  20. GRB 050607: MDM Observation
  21. GRB 050607 optical decay
  22. GRB 050607: RTT150 optical observations
  23. GRB050607: refined analysis of prompt REM observations
  24. Swift/UVOT observations of GRB050607
  25. GRB 050607 : Lulin R-band observation
  26. GRB 050607: PROMPT VRcIc Observations
  27. GRB 050607: RAPTOR-S Early Optical Limits
  28. GRB050607: KAIT optical limits
  29. GRB 050525a, Mid-Infrared Observations
  30. GRB 050607: Optical decay and spectral slope
  31. GRB 050607: MDM Observations
  32. GRB050607,optical observation
  33. GRB 050607 - XRT refined data analysis
  34. Optical Afterglow of GRB 050607
  35. GRB050607 optical limit by "Pi of the Sky"
  36. GRB050607: Swift Detection of a long GRB
  37. GRB050607: P60 Observations
  38. GRB050607: prompt REM observations
  39. GRB 050603: prediction of t_break
  40. Limits on a SN in the field of GRB 050509b
  41. GRB 050603: Redshift
  42. GRB 050603 - XRT data analysis of the first day
  43. Konus-Wind observation of GRB 050603
  44. GRB 050603: Analysis of UVOT data
  45. GRB050603: Fading Afterglow observed by Swift UVOT
  46. GRB050603, submillimetre observations
  47. GRB 050603: Swift XRT Position
  48. GRB050603: Radio Detection
  49. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  50. GRB 050603: Afterglow Identification from LCO
  51. GRB 050603: INTEGRAL shows it is not a short GRB
  52. Swift/BAT Detection of GRB050603
  53. GRB 050408: jet break in the XRT light curve
  54. GRB 050525a, infrared observations
  55. GRB 050525a, SMARTS optical/IR afterglow observations
  56. GRB050528, XRT observations
  57. Correction to GCN Circ 3502 on GRB 050528
  58. GRB050528: updated Liverpool Telescope limits
  59. Swift-BAT GRB 050528: a soft burst
  60. Update on Swift-BAT GRB 050528 (Trigger 130679)
  61. GRB050528: BOOTES optical candidate (retraction)
  62. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  63. GRB050528: BOOTES optical candidate
  64. Possible GRB050528: no candidate from Liverpool Telescope
  65. Swift-BAT detection of possible GRB 050528
  66. GRB050525a: Radio Observations
  67. GRB 050509b: refined XRT/Chandra afterglow position analysis
  68. GRB 050525: RTT150, Optical observations
  69. GRB050525a: optical upper limits
  70. GRB 050525a: SARA Observations
  71. GRB 050525B: Swift-BAT observations
  72. GRB 050525: MITSuME Optical Observation in VRI
  73. GRB 050525a: MDM Observations
  74. GRB050525A,optical observation
  75. GRB 050525 : Lulin optical afterglow observations
  76. GRB050525: Super-LOTIS observations
  77. GRB 050525, spectral lag pseudo-redshift
  78. GRB 050525a: Gemini/GMOS Spectra
  79. GRB050306: optical afterglow not confirmed
  80. GRB 050525: BART optical observation
  81. GRB 050525A: BOOTES simultaneous optical observations
  82. GRB 050525A: Swift-BAT refined analysis
  83. GRB050525: Optical observations
  84. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  85. GRB 050525: pseudo-redshift
  86. Swift/UVOT UV and optical detections of GRB 050525
  87. Konus-Wind observation of GRB 050525
  88. GRB 050525: TAROT observations of the early afterglow
  89. INTEGRAL detection of GRB 050525
  90. GRB 050525, infrared observations
  91. GRB 050525: Optical observation
  92. GRB 050525: observatons of the optical afterglow
  93. GRB050525: ROTSE-III Refined Analysis
  94. GRB 050525 - Very Bright, Not Short
  95. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  96. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  97. XRF050522: NIR observations of XRT candidate
  98. XRF 050522: Swift XRT refined analysis
  99. XRF050522: Radio Observations
  100. Swift/UVOT observation of XRF 050522

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