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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"

35343 results found.

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

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