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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"

26368 results found.

  1. GRB050607,optical observation
  2. Optical Afterglow of GRB 050607
  3. GRB050607: Swift Detection of a long GRB
  4. GRB050607: prompt REM observations
  5. Limits on a SN in the field of GRB 050509b
  6. GRB 050603 - XRT data analysis of the first day
  7. GRB050603, submillimetre observations
  8. GRB050603: Radio Detection
  9. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  10. GRB 050603: INTEGRAL shows it is not a short GRB
  11. GRB 050525a, infrared observations
  12. GRB050528, XRT observations
  13. GRB050528: updated Liverpool Telescope limits
  14. Swift-BAT GRB 050528: a soft burst
  15. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  16. Possible GRB050528: no candidate from Liverpool Telescope
  17. GRB050525a: Radio Observations
  18. GRB 050509b: refined XRT/Chandra afterglow position analysis
  19. GRB 050525: RTT150, Optical observations
  20. GRB 050525a: SARA Observations
  21. GRB 050525B: Swift-BAT observations
  22. GRB 050525: MITSuME Optical Observation in VRI
  23. GRB050525A,optical observation
  24. GRB050525: Super-LOTIS observations
  25. GRB 050525, spectral lag pseudo-redshift
  26. GRB050306: optical afterglow not confirmed
  27. GRB 050525: BART optical observation
  28. GRB 050525A: BOOTES simultaneous optical observations
  29. GRB 050525A: Swift-BAT refined analysis
  30. GRB050525: Optical observations
  31. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  32. Konus-Wind observation of GRB 050525
  33. GRB 050525: TAROT observations of the early afterglow
  34. INTEGRAL detection of GRB 050525
  35. GRB 050525, infrared observations
  36. GRB 050525: observatons of the optical afterglow
  37. GRB050525: ROTSE-III Refined Analysis
  38. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  39. XRF050522: Radio Observations
  40. Swift/UVOT observation of XRF 050522
  41. GRB 050509A: Further I-band imaging
  42. GRB050522,optical observation
  43. GRB050520,optical observation
  44. XRF 050522: Continued NIR P200 Monitoring
  45. RBO Observations of GRB050522
  46. Recent GRB BVRcIc field photometry
  47. GRB050520: Radio Observations
  48. XRF 050522: Swift XRT observation
  49. XRF050522, BVRcIc field photometry
  50. XRF050522: Optical Observations
  51. XRF050522: Near-infrared Observations
  52. GRB 050520: VLT/ULTRACAM observations
  53. GRB 050520: Swift XRT refined analysis
  54. XRF050509C: Chandra Afterglow Detection
  55. XRF050509c: Radio Observations
  56. GRB 050520: P200 Observations
  57. GRB 050520: TAROT optical limit
  58. GRB 050520: VLT/ULTRACAM observations
  59. XRF 050509c optical afterglow
  60. GRB 050509B and short GRB-SN association? (corrected)
  61. GRB 050509B and short GRB-SN association?
  62. GRB050502b: Early Observation
  63. GRB050509b, Bok telescope B-band imaging
  64. Refined Chandra analysis of GRB 050509b
  65. GRB050509b, SDSS pre-burst observations
  66. GRB 050509b: Keck/Chandra Cross-Correlation
  67. GRB 050509b: Keck/Chandra Cross-Correlation
  68. Chandra observation of GRB 050509b
  69. GRB 050509b: RAPTOR deep, early limits.
  70. GRB050509B: Optical observations at the Very Large Telescope
  71. GRB 050509b: No Optical Variability in XRT Error Circle
  72. GRB 050509a: Swift-BAT refined analysis
  73. GRB 050509c: ROTSE-III Optical Limits
  74. GRB 050505, early TAROT observation
  75. GRB050509c: REM NIR and Optical observations
  76. GRB 050509b: Physical Properties of the Candidate Host galaxy
  77. GRB 050505: SARA Observations
  78. GRB 050509B, Optical Observations
  79. GRB 050509B: Swift/XRT refined analysis
  80. GRB 050509b: Optical observations
  81. GRB 050509A: Optical observations
  82. GRB050509b: Radio Observations
  83. GRB 050509b: PAIRITEL and WIYN Observations
  84. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  85. Swift Detection of GRB050509b: A short duration burst
  86. Swift Detection of the Burst GRB050509
  87. GRB 050505: early time observations
  88. GRB 050505, simultaneous optical observation
  89. GRB050505: AAVSO observations
  90. GRB050416A : 1 GHz limit from GMRT
  91. GRB050505: Optical Afterglow Candidate
  92. GRB050505 Swift-BAT refined analysis
  93. GRB 050416b:Swift XRT afterglow upper limits
  94. GRB 050416b:Swift XRT afterglow upper limits
  95. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  96. GRB050502b: Afterglow Confirmation
  97. GRB050502: P200 Observations (Correction)
  98. GRB050502: P200 Observations
  99. GRB 050504 : R band observation at Lulin observatory
  100. Swift UVOT observation of GRB 050504

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