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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"

33773 results found.

  1. GRB 050701, optical observations
  2. GRB 050408: ARC 3.5-meter NIR Observations
  3. GRB 050701: Refined XRT analysis
  4. Swift UVOT observations of GRB 050701
  5. GRB 050701: Swift XRT afterglow position
  6. Swift trigger 143708 is really GRB 050701
  7. GRB 050607, radio observations
  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. H3804: A Possible New XRB Detected by HETE
  12. XRF 050509c: Optical monitoring
  13. IBAS Alert #2512 is NOT a GRB
  14. GRB 050416(a): Host Galaxy Redshift Determination
  15. GRB 050607: MDM Observation
  16. GRB 050607 optical decay
  17. GRB 050607: RTT150 optical observations
  18. GRB 050607 : Lulin R-band observation
  19. GRB 050607: PROMPT VRcIc Observations
  20. GRB 050607: RAPTOR-S Early Optical Limits
  21. GRB 050525a, Mid-Infrared Observations
  22. GRB 050607: Optical decay and spectral slope
  23. GRB 050607: MDM Observations
  24. GRB050607,optical observation
  25. GRB 050607 - XRT refined data analysis
  26. Optical Afterglow of GRB 050607
  27. GRB050607 optical limit by "Pi of the Sky"
  28. GRB050607: Swift Detection of a long GRB
  29. GRB050607: P60 Observations
  30. GRB 050603: prediction of t_break
  31. Limits on a SN in the field of GRB 050509b
  32. GRB 050603: Redshift
  33. GRB 050603 - XRT data analysis of the first day
  34. Konus-Wind observation of GRB 050603
  35. GRB 050603: Analysis of UVOT data
  36. GRB 050603: Swift XRT Position
  37. GRB050603: Radio Detection
  38. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  39. GRB 050603: Afterglow Identification from LCO
  40. GRB 050603: INTEGRAL shows it is not a short GRB
  41. GRB 050408: jet break in the XRT light curve
  42. GRB 050525a, infrared observations
  43. GRB 050525a, SMARTS optical/IR afterglow observations
  44. Correction to GCN Circ 3502 on GRB 050528
  45. GRB050528: updated Liverpool Telescope limits
  46. Swift-BAT GRB 050528: a soft burst
  47. Update on Swift-BAT GRB 050528 (Trigger 130679)
  48. GRB050528: BOOTES optical candidate (retraction)
  49. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  50. GRB050528: BOOTES optical candidate
  51. Possible GRB050528: no candidate from Liverpool Telescope
  52. Swift-BAT detection of possible GRB 050528
  53. GRB050525a: Radio Observations
  54. GRB 050509b: refined XRT/Chandra afterglow position analysis
  55. GRB 050525: RTT150, Optical observations
  56. GRB050525a: optical upper limits
  57. GRB 050525a: SARA Observations
  58. GRB 050525B: Swift-BAT observations
  59. GRB 050525: MITSuME Optical Observation in VRI
  60. GRB 050525a: MDM Observations
  61. GRB050525A,optical observation
  62. GRB 050525 : Lulin optical afterglow observations
  63. GRB050525: Super-LOTIS observations
  64. GRB 050525, spectral lag pseudo-redshift
  65. GRB 050525a: Gemini/GMOS Spectra
  66. GRB050306: optical afterglow not confirmed
  67. GRB 050525: BART optical observation
  68. GRB 050525A: BOOTES simultaneous optical observations
  69. GRB 050525A: Swift-BAT refined analysis
  70. GRB050525: Optical observations
  71. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  72. GRB 050525: pseudo-redshift
  73. Swift/UVOT UV and optical detections of GRB 050525
  74. Konus-Wind observation of GRB 050525
  75. GRB 050525: TAROT observations of the early afterglow
  76. INTEGRAL detection of GRB 050525
  77. GRB 050525, infrared observations
  78. GRB 050525: Optical observation
  79. GRB 050525: observatons of the optical afterglow
  80. GRB050525: ROTSE-III Refined Analysis
  81. GRB 050525 - Very Bright, Not Short
  82. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  83. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  84. XRF050522: NIR observations of XRT candidate
  85. XRF050522: Radio Observations
  86. GRB 050509A: Further I-band imaging
  87. GRB050522,optical observation
  88. GRB050520,optical observation
  89. XRF 050522: Continued NIR P200 Monitoring
  90. RBO Observations of GRB050522
  91. GRB050509b: optical observations
  92. Recent GRB BVRcIc field photometry
  93. GRB050520: Radio Observations
  94. XRF050522, BVRcIc field photometry
  95. XRF050522: Optical Observations
  96. XRF 050522: KAIT observations
  97. XRF 050522 detected with INTEGRAL
  98. GRB 050520: VLT/ULTRACAM observations
  99. Swift UVOT Observations of GRB 050520
  100. GRB 050520: Swift XRT refined analysis

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