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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"

45451 results found.

  1. GRB050528: BOOTES optical candidate (retraction)
  2. GRB050504: Ashra-P2/3 monitor and Ashra-AFT response
  3. GRB050528: BOOTES optical candidate
  4. Possible GRB050528: no candidate from Liverpool Telescope
  5. Swift-BAT detection of possible GRB 050528
  6. GRB050525a: Radio Observations
  7. GRB 050509b: refined XRT/Chandra afterglow position analysis
  8. GRB 050525: RTT150, Optical observations
  9. GRB050525a: optical upper limits
  10. GRB 050525a: SARA Observations
  11. GRB 050525B: Swift-BAT observations
  12. GRB 050525: MITSuME Optical Observation in VRI
  13. GRB 050525a: MDM Observations
  14. GRB050525A,optical observation
  15. GRB 050525 : Lulin optical afterglow observations
  16. GRB050525: Super-LOTIS observations
  17. GRB 050525, spectral lag pseudo-redshift
  18. GRB 050525a: Gemini/GMOS Spectra
  19. GRB050306: optical afterglow not confirmed
  20. GRB 050525: BART optical observation
  21. GRB 050525A: BOOTES simultaneous optical observations
  22. GRB 050525A: Swift-BAT refined analysis
  23. GRB050525: Optical observations
  24. GRB 050525B: INTEGRAL shows it is unrelated to GRB050525A
  25. GRB 050525: pseudo-redshift
  26. Swift/UVOT UV and optical detections of GRB 050525
  27. Konus-Wind observation of GRB 050525
  28. GRB 050525: TAROT observations of the early afterglow
  29. INTEGRAL detection of GRB 050525
  30. GRB 050525, infrared observations
  31. GRB 050525: Optical observation
  32. GRB 050525: observatons of the optical afterglow
  33. GRB050525: ROTSE-III Refined Analysis
  34. GRB 050525 - Very Bright, Not Short
  35. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  36. GRB 050525A: ROTSE-III Detection of Possible Counterpart
  37. XRF050522: NIR observations of XRT candidate
  38. XRF 050522: Swift XRT refined analysis
  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. GRB050509b: optical observations
  47. Recent GRB BVRcIc field photometry
  48. GRB050520: Radio Observations
  49. XRF 050522: Swift XRT observation
  50. XRF050522, BVRcIc field photometry
  51. XRF 050522 : Lulin observations
  52. XRF050522: Optical Observations
  53. XRF050522: Near-infrared Observations
  54. XRF 050522: KAIT observations
  55. XRF 050522 detected with INTEGRAL
  56. GRB 050520: VLT/ULTRACAM observations
  57. Swift UVOT Observations of GRB 050520
  58. GRB 050520: Swift XRT refined analysis
  59. XRF050509C: Chandra Afterglow Detection
  60. XRF 050509c: Swift XRT Upper Limit
  61. XRF050509c: Radio Observations
  62. RBO Observations of GRB050520
  63. GRB 050520: P200 Observations
  64. GRB050520: Liverpool Telescope follow-up
  65. RBO Observations of GRB050520
  66. GRB 050520: TAROT optical limit
  67. GRB 050520: Swift XRT position
  68. GRB 050520: VLT/ULTRACAM observations
  69. GRB 050520: OSN optical observations
  70. GRB 050520: BART optical limit
  71. GRB 050520 - A long GRB detected with INTEGRAL
  72. No Swift-BAT Lightcurves in real-time for next 3 weeks
  73. Swift-BAT trigger 122203 is not a real GRB
  74. XRF 050509C: REM NIR and Optical refined analysis
  75. GRB 050504: Swift XRT afterglow candidate has faded
  76. XRF 050509c optical afterglow
  77. GRB 050509B and short GRB-SN association? (corrected)
  78. GRB 050509B and short GRB-SN association?
  79. GRB 050509B: Subaru Optical Observations
  80. GRB050502b: Early Observation
  81. GRB050509b, Bok telescope B-band imaging
  82. Refined Chandra analysis of GRB 050509b
  83. GRB050509b, SDSS pre-burst observations
  84. GRB 050509b: Keck/Chandra Cross-Correlation
  85. GRB 050509b: Keck/Chandra Cross-Correlation
  86. Chandra observation of GRB 050509b
  87. GRB 050509b: RAPTOR deep, early limits.
  88. GRB050509B: Optical/Infared observations
  89. GRB 050509b: Swift/UVOT follow-up measurements
  90. GRB 050509b Milagro GeV/TeV Observations
  91. GRB050509B: Optical observations at the Very Large Telescope
  92. GRB 050509b: No Optical Variability in XRT Error Circle
  93. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  94. GRB 050509a: Swift-BAT refined analysis
  95. GRB 050509c: ROTSE-III Optical Limits
  96. GRB 050509B: WSRT Radio Observations
  97. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  98. GRB 050505, early TAROT observation
  99. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  100. GRB 050509b: Further Analysis of Keck LRIS Images

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