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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"

25083 results found.

  1. GRB 050701: Refined XRT analysis
  2. Swift UVOT observations of GRB 050701
  3. GRB050701: Swift-BAT Refined analysis
  4. Swift trigger 143708 is really GRB 050701
  5. GRB 050607, radio observations
  6. H11603: An X-ray flare from V4641 Sgr, or a possible XRF
  7. GRB050525a: HST Observations
  8. H3800 and H3801 on 2005 June 11: two bursts from SGR1806-20 localized by HETE
  9. XRF 050509c: Optical monitoring
  10. Konus-Wind observation of an intermediate burst from SGR 1806-20
  11. XRF050509c: Radio Detection
  12. GRB 050607 optical decay
  13. GRB050607: refined analysis of prompt REM observations
  14. GRB 050607: PROMPT VRcIc Observations
  15. GRB 050607: Optical decay and spectral slope
  16. GRB050607,optical observation
  17. Optical Afterglow of GRB 050607
  18. GRB050607: Swift Detection of a long GRB
  19. GRB050607: prompt REM observations
  20. Limits on a SN in the field of GRB 050509b
  21. GRB 050603 - XRT data analysis of the first day
  22. GRB050603, submillimetre observations
  23. GRB050603: Radio Detection
  24. GRB 050603: Swift-BAT refined analysis of a long three-spiked burst
  25. GRB 050603: INTEGRAL shows it is not a short GRB
  26. GRB 050525a, infrared observations
  27. GRB050528, XRT observations
  28. GRB050528: updated Liverpool Telescope limits
  29. Swift-BAT GRB 050528: a soft burst
  30. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  31. Possible GRB050528: no candidate from Liverpool Telescope
  32. GRB050525a: Radio Observations
  33. GRB 050509b: refined XRT/Chandra afterglow position analysis
  34. GRB 050525: RTT150, Optical observations
  35. GRB 050525a: SARA Observations
  36. GRB 050525B: Swift-BAT observations
  37. GRB 050525: MITSuME Optical Observation in VRI
  38. GRB050525A,optical observation
  39. GRB050525: Super-LOTIS observations
  40. GRB 050525, spectral lag pseudo-redshift
  41. GRB050306: optical afterglow not confirmed
  42. GRB 050525: BART optical observation
  43. GRB 050525A: BOOTES simultaneous optical observations
  44. GRB 050525A: Swift-BAT refined analysis
  45. GRB050525: Optical observations
  46. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  47. Konus-Wind observation of GRB 050525
  48. GRB 050525: TAROT observations of the early afterglow
  49. INTEGRAL detection of GRB 050525
  50. GRB 050525, infrared observations
  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. RBO Observations of GRB050522
  61. Recent GRB BVRcIc field photometry
  62. GRB050520: Radio Observations
  63. XRF 050522: Swift XRT observation
  64. XRF050522, BVRcIc field photometry
  65. XRF050522: Optical Observations
  66. XRF050522: Near-infrared Observations
  67. GRB 050520: VLT/ULTRACAM observations
  68. GRB 050520: Swift XRT refined analysis
  69. XRF050509C: Chandra Afterglow Detection
  70. XRF050509c: Radio Observations
  71. GRB 050520: P200 Observations
  72. GRB 050520: TAROT optical limit
  73. GRB 050520: VLT/ULTRACAM observations
  74. XRF 050509c optical afterglow
  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. Refined Chandra analysis of GRB 050509b
  80. GRB050509b, SDSS pre-burst observations
  81. GRB 050509b: Keck/Chandra Cross-Correlation
  82. GRB 050509b: Keck/Chandra Cross-Correlation
  83. Chandra observation of GRB 050509b
  84. GRB 050509b: RAPTOR deep, early limits.
  85. GRB050509B: Optical observations at the Very Large Telescope
  86. GRB 050509b: No Optical Variability in XRT Error Circle
  87. GRB 050509a: Swift-BAT refined analysis
  88. GRB 050509c: ROTSE-III Optical Limits
  89. GRB 050505, early TAROT observation
  90. GRB050509c: REM NIR and Optical observations
  91. GRB 050509b: Physical Properties of the Candidate Host galaxy
  92. GRB 050505: SARA Observations
  93. GRB 050509B, Optical Observations
  94. GRB 050509B: Swift/XRT refined analysis
  95. GRB 050509b: Optical observations
  96. GRB 050509A: Optical observations
  97. GRB050509b: Radio Observations
  98. GRB 050509b: PAIRITEL and WIYN Observations
  99. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  100. Swift Detection of GRB050509b: A short duration burst

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