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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"

45461 results found.

  1. GRB 050603: Afterglow Identification from LCO
  2. GRB 050603: INTEGRAL shows it is not a short GRB
  3. Swift/BAT Detection of GRB050603
  4. GRB 050408: jet break in the XRT light curve
  5. GRB 050525a, infrared observations
  6. GRB 050525a, SMARTS optical/IR afterglow observations
  7. GRB050528, XRT observations
  8. Correction to GCN Circ 3502 on GRB 050528
  9. GRB050528: updated Liverpool Telescope limits
  10. Swift-BAT GRB 050528: a soft burst
  11. Update on Swift-BAT GRB 050528 (Trigger 130679)
  12. GRB050528: BOOTES optical candidate (retraction)
  13. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  14. GRB050528: BOOTES optical candidate
  15. Possible GRB050528: no candidate from Liverpool Telescope
  16. Swift-BAT detection of possible GRB 050528
  17. GRB050525a: Radio Observations
  18. GRB 050509b: refined XRT/Chandra afterglow position analysis
  19. GRB 050525: RTT150, Optical observations
  20. GRB050525a: optical upper limits
  21. GRB 050525a: SARA Observations
  22. GRB 050525B: Swift-BAT observations
  23. GRB 050525: MITSuME Optical Observation in VRI
  24. GRB 050525a: MDM Observations
  25. GRB050525A,optical observation
  26. GRB 050525 : Lulin optical afterglow observations
  27. GRB050525: Super-LOTIS observations
  28. GRB 050525, spectral lag pseudo-redshift
  29. GRB 050525a: Gemini/GMOS Spectra
  30. GRB050306: optical afterglow not confirmed
  31. GRB 050525: BART optical observation
  32. GRB 050525A: BOOTES simultaneous optical observations
  33. GRB 050525A: Swift-BAT refined analysis
  34. GRB050525: Optical observations
  35. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  36. GRB 050525: pseudo-redshift
  37. Swift/UVOT UV and optical detections of GRB 050525
  38. Konus-Wind observation of GRB 050525
  39. GRB 050525: TAROT observations of the early afterglow
  40. INTEGRAL detection of GRB 050525
  41. GRB 050525, infrared observations
  42. GRB 050525: Optical observation
  43. GRB 050525: observatons of the optical afterglow
  44. GRB050525: ROTSE-III Refined Analysis
  45. GRB 050525 - Very Bright, Not Short
  46. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  47. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  48. XRF050522: NIR observations of XRT candidate
  49. XRF 050522: Swift XRT refined analysis
  50. XRF050522: Radio Observations
  51. Swift/UVOT observation of XRF 050522
  52. GRB 050509A: Further I-band imaging
  53. GRB050522,optical observation
  54. GRB050520,optical observation
  55. XRF 050522: Continued NIR P200 Monitoring
  56. RBO Observations of GRB050522
  57. GRB050509b: optical observations
  58. Recent GRB BVRcIc field photometry
  59. GRB050520: Radio Observations
  60. XRF 050522: Swift XRT observation
  61. XRF050522, BVRcIc field photometry
  62. XRF 050522 : Lulin observations
  63. XRF050522: Optical Observations
  64. XRF050522: Near-infrared Observations
  65. XRF 050522: KAIT observations
  66. XRF 050522 detected with INTEGRAL
  67. GRB 050520: VLT/ULTRACAM observations
  68. Swift UVOT Observations of GRB 050520
  69. GRB 050520: Swift XRT refined analysis
  70. XRF050509C: Chandra Afterglow Detection
  71. XRF 050509c: Swift XRT Upper Limit
  72. XRF050509c: Radio Observations
  73. RBO Observations of GRB050520
  74. GRB 050520: P200 Observations
  75. GRB050520: Liverpool Telescope follow-up
  76. RBO Observations of GRB050520
  77. GRB 050520: TAROT optical limit
  78. GRB 050520: Swift XRT position
  79. GRB 050520: VLT/ULTRACAM observations
  80. GRB 050520: OSN optical observations
  81. GRB 050520: BART optical limit
  82. GRB 050520 - A long GRB detected with INTEGRAL
  83. No Swift-BAT Lightcurves in real-time for next 3 weeks
  84. Swift-BAT trigger 122203 is not a real GRB
  85. XRF 050509C: REM NIR and Optical refined analysis
  86. GRB 050504: Swift XRT afterglow candidate has faded
  87. XRF 050509c optical afterglow
  88. GRB 050509B and short GRB-SN association? (corrected)
  89. GRB 050509B and short GRB-SN association?
  90. GRB 050509B: Subaru Optical Observations
  91. GRB050502b: Early Observation
  92. GRB050509b, Bok telescope B-band imaging
  93. Refined Chandra analysis of GRB 050509b
  94. GRB050509b, SDSS pre-burst observations
  95. GRB 050509b: Keck/Chandra Cross-Correlation
  96. GRB 050509b: Keck/Chandra Cross-Correlation
  97. Chandra observation of GRB 050509b
  98. GRB 050509b: RAPTOR deep, early limits.
  99. GRB050509B: Optical/Infared observations
  100. GRB 050509b: Swift/UVOT follow-up measurements

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