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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"

20866 results found.

  1. Possible GRB050528: no candidate from Liverpool Telescope
  2. Swift-BAT detection of possible GRB 050528
  3. GRB050525a: Radio Observations
  4. GRB 050509b: refined XRT/Chandra afterglow position analysis
  5. GRB 050525: RTT150, Optical observations
  6. GRB 050525a: SARA Observations
  7. GRB 050525B: Swift-BAT observations
  8. GRB 050525: MITSuME Optical Observation in VRI
  9. GRB050525A,optical observation
  10. GRB050525: Super-LOTIS observations
  11. GRB050306: optical afterglow not confirmed
  12. GRB 050525: BART optical observation
  13. GRB 050525A: BOOTES simultaneous optical observations
  14. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  15. Konus-Wind observation of GRB 050525
  16. GRB 050525: TAROT observations of the early afterglow
  17. INTEGRAL detection of GRB 050525
  18. GRB 050525, infrared observations
  19. GRB 050525: observatons of the optical afterglow
  20. GRB050525: ROTSE-III Refined Analysis
  21. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  22. XRF050522: Radio Observations
  23. Swift/UVOT observation of XRF 050522
  24. GRB 050509A: Further I-band imaging
  25. GRB050522,optical observation
  26. GRB050520,optical observation
  27. XRF 050522: Continued NIR P200 Monitoring
  28. Recent GRB BVRcIc field photometry
  29. GRB050520: Radio Observations
  30. XRF 050522: Swift XRT observation
  31. XRF050522, BVRcIc field photometry
  32. XRF050522: Optical Observations
  33. XRF050522: Near-infrared Observations
  34. GRB 050520: VLT/ULTRACAM observations
  35. Swift UVOT Observations of GRB 050520
  36. GRB 050520: Swift XRT refined analysis
  37. XRF 050509c: Swift XRT Upper Limit
  38. XRF050509c: Radio Observations
  39. RBO Observations of GRB050520
  40. GRB 050520: P200 Observations
  41. GRB050520: Liverpool Telescope follow-up
  42. GRB 050520: TAROT optical limit
  43. GRB 050520: VLT/ULTRACAM observations
  44. GRB 050520: OSN optical observations
  45. No Swift-BAT Lightcurves in real-time for next 3 weeks
  46. XRF 050509C: REM NIR and Optical refined analysis
  47. GRB 050504: Swift XRT afterglow candidate has faded
  48. GRB 050509B and short GRB-SN association? (corrected)
  49. GRB 050509B and short GRB-SN association?
  50. GRB050502b: Early Observation
  51. GRB050509b, Bok telescope B-band imaging
  52. GRB050509b, SDSS pre-burst observations
  53. GRB 050509b: Keck/Chandra Cross-Correlation
  54. GRB 050509b: Keck/Chandra Cross-Correlation
  55. Chandra observation of GRB 050509b
  56. GRB 050509b: Swift/UVOT follow-up measurements
  57. GRB050509B: Optical observations at the Very Large Telescope
  58. GRB 050509b: No Optical Variability in XRT Error Circle
  59. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  60. GRB 050509c: ROTSE-III Optical Limits
  61. GRB 050509B: WSRT Radio Observations
  62. GRB 050505, early TAROT observation
  63. GRB050509c: REM NIR and Optical observations
  64. GRB 050505: SARA Observations
  65. GRB 050509B: Swift/XRT refined analysis
  66. GRB 050509b: Optical observations
  67. GRB 050509b: Possible Optical Counterpart
  68. GRB 050509A: Optical observations
  69. GRB050509b: Radio Observations
  70. GRB 050509B: ROTSE-III Optical Limits
  71. Swift Detection of GRB050509b: A short duration burst
  72. Swift Detection of the Burst GRB050509
  73. Swift-BAT detection of GRB 050507
  74. GRB 050502a: Swift XRT Upper Limit
  75. GRB 050505, simultaneous optical observation
  76. GRB 050505: Further Swift UVOT observations.
  77. GRB050505: AAVSO observations
  78. GRB050416A : 1 GHz limit from GMRT
  79. GRB050505: Optical Afterglow Candidate
  80. GRB050505 Swift-BAT refined analysis
  81. GRB 050416b:Swift XRT afterglow upper limits
  82. GRB 050416b:Swift XRT afterglow upper limits
  83. Swift-BAT detection of GRB050505
  84. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  85. GRB050502b: Afterglow Confirmation
  86. GRB050502: P200 Observations (Correction)
  87. GRB050502: P200 Observations
  88. Swift UVOT observation of GRB 050504
  89. GRB050504: P60 Observations
  90. GRB (?) 050504: IR Observations, Intriguing Source
  91. GRB 050502b, Optical observations
  92. GRB050502a: P60 Observations (Correction)
  93. GRB050502a: P60 Observations
  94. GRB 050502A: WSRT Radio Observations
  95. GRB050502A: Optical Observations
  96. GRB050502B Swift-BAT refined analysis
  97. GRB 050502A: Redshift measurement based on Keck HIRES Observations
  98. Swift Detection of the Bright Burst GRB050502b
  99. GRB050502 - Optical Candidate from the Liverpool Telescope
  100. GRB 050502: ROTSE-III Detection of Possible Counterpart

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