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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"

20350 results found.

  1. GRB 050525a: ARC 3.5-meter Optical and NIR Observations
  2. GRB 050525a: ARC 3.5-Meter SPIcam Field Calibration
  3. GRB 050626 optical observations
  4. GRB 050408: ARC 3.5-meter NIR Observations
  5. Swift UVOT observations of GRB 050701
  6. GRB 050607, radio observations
  7. GRB050525a: HST Observations
  8. XRF 050509c: Optical monitoring
  9. XRF050509c: Radio Detection
  10. GRB 050607 optical decay
  11. GRB050607: refined analysis of prompt REM observations
  12. GRB 050607: PROMPT VRcIc Observations
  13. GRB 050607: Optical decay and spectral slope
  14. GRB050607,optical observation
  15. Optical Afterglow of GRB 050607
  16. GRB050607: Swift Detection of a long GRB
  17. GRB050607: prompt REM observations
  18. Limits on a SN in the field of GRB 050509b
  19. GRB050603, submillimetre observations
  20. GRB050603: Radio Detection
  21. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  22. GRB 050603: Afterglow Identification from LCO
  23. GRB 050603: INTEGRAL shows it is not a short GRB
  24. Swift/BAT Detection of GRB050603
  25. GRB 050525a, infrared observations
  26. GRB050528: updated Liverpool Telescope limits
  27. Swift-BAT GRB 050528: a soft burst
  28. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  29. Possible GRB050528: no candidate from Liverpool Telescope
  30. Swift-BAT detection of possible GRB 050528
  31. GRB050525a: Radio Observations
  32. GRB 050509b: refined XRT/Chandra afterglow position analysis
  33. GRB 050525: RTT150, Optical observations
  34. GRB 050525a: SARA Observations
  35. GRB 050525B: Swift-BAT observations
  36. GRB 050525: MITSuME Optical Observation in VRI
  37. GRB050525A,optical observation
  38. GRB 050525 : Lulin optical afterglow observations
  39. GRB050525: Super-LOTIS observations
  40. GRB050306: optical afterglow not confirmed
  41. GRB 050525: BART optical observation
  42. GRB 050525A: BOOTES simultaneous optical observations
  43. GRB 050525A: Swift-BAT refined analysis
  44. GRB050525: Optical observations
  45. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  46. Konus-Wind observation of GRB 050525
  47. GRB 050525: TAROT observations of the early afterglow
  48. INTEGRAL detection of GRB 050525
  49. GRB 050525, infrared observations
  50. GRB 050525: Optical observation
  51. GRB 050525: observatons of the optical afterglow
  52. GRB050525: ROTSE-III Refined Analysis
  53. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  54. XRF050522: Radio Observations
  55. Swift/UVOT observation of XRF 050522
  56. GRB 050509A: Further I-band imaging
  57. GRB050522,optical observation
  58. GRB050520,optical observation
  59. XRF 050522: Continued NIR P200 Monitoring
  60. Recent GRB BVRcIc field photometry
  61. GRB050520: Radio Observations
  62. XRF 050522: Swift XRT observation
  63. XRF050522, BVRcIc field photometry
  64. XRF050522: Optical Observations
  65. XRF050522: Near-infrared Observations
  66. GRB 050520: VLT/ULTRACAM observations
  67. GRB 050520: Swift XRT refined analysis
  68. XRF 050509c: Swift XRT Upper Limit
  69. XRF050509c: Radio Observations
  70. RBO Observations of GRB050520
  71. GRB 050520: P200 Observations
  72. GRB 050520: TAROT optical limit
  73. GRB 050520: VLT/ULTRACAM observations
  74. GRB 050504: Swift XRT afterglow candidate has faded
  75. GRB 050509B and short GRB-SN association? (corrected)
  76. GRB 050509B and short GRB-SN association?
  77. GRB050502b: Early Observation
  78. GRB050509b, Bok telescope B-band imaging
  79. GRB050509b, SDSS pre-burst observations
  80. GRB 050509b: Keck/Chandra Cross-Correlation
  81. GRB 050509b: Keck/Chandra Cross-Correlation
  82. Chandra observation of GRB 050509b
  83. GRB050509B: Optical observations at the Very Large Telescope
  84. GRB 050509b: No Optical Variability in XRT Error Circle
  85. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  86. GRB 050509c: ROTSE-III Optical Limits
  87. GRB 050505, early TAROT observation
  88. GRB050509c: REM NIR and Optical observations
  89. GRB 050505: SARA Observations
  90. GRB 050509B, Optical Observations
  91. GRB 050509b: Possible Optical Counterpart
  92. GRB 050509A: Optical observations
  93. GRB050509b: Radio Observations
  94. Swift Detection of GRB050509b: A short duration burst
  95. Swift Detection of the Burst GRB050509
  96. Swift-BAT detection of GRB 050507
  97. GRB 050502a: Swift XRT Upper Limit
  98. GRB 050505, simultaneous optical observation
  99. GRB050505: AAVSO observations
  100. GRB050416A : 1 GHz limit from GMRT

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