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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"

45655 results found.

  1. XRF050522: Radio Observations
  2. Swift/UVOT observation of XRF 050522
  3. GRB 050509A: Further I-band imaging
  4. GRB050522,optical observation
  5. GRB050520,optical observation
  6. XRF 050522: Continued NIR P200 Monitoring
  7. RBO Observations of GRB050522
  8. GRB050509b: optical observations
  9. Recent GRB BVRcIc field photometry
  10. GRB050520: Radio Observations
  11. XRF 050522: Swift XRT observation
  12. XRF050522, BVRcIc field photometry
  13. XRF 050522 : Lulin observations
  14. XRF050522: Optical Observations
  15. XRF050522: Near-infrared Observations
  16. XRF 050522: KAIT observations
  17. XRF 050522 detected with INTEGRAL
  18. GRB 050520: VLT/ULTRACAM observations
  19. Swift UVOT Observations of GRB 050520
  20. GRB 050520: Swift XRT refined analysis
  21. XRF050509C: Chandra Afterglow Detection
  22. XRF 050509c: Swift XRT Upper Limit
  23. XRF050509c: Radio Observations
  24. RBO Observations of GRB050520
  25. GRB 050520: P200 Observations
  26. GRB050520: Liverpool Telescope follow-up
  27. RBO Observations of GRB050520
  28. GRB 050520: TAROT optical limit
  29. GRB 050520: Swift XRT position
  30. GRB 050520: VLT/ULTRACAM observations
  31. GRB 050520: OSN optical observations
  32. GRB 050520: BART optical limit
  33. GRB 050520 - A long GRB detected with INTEGRAL
  34. No Swift-BAT Lightcurves in real-time for next 3 weeks
  35. Swift-BAT trigger 122203 is not a real GRB
  36. XRF 050509C: REM NIR and Optical refined analysis
  37. GRB 050504: Swift XRT afterglow candidate has faded
  38. XRF 050509c optical afterglow
  39. GRB 050509B and short GRB-SN association? (corrected)
  40. GRB 050509B and short GRB-SN association?
  41. GRB 050509B: Subaru Optical Observations
  42. GRB050502b: Early Observation
  43. GRB050509b, Bok telescope B-band imaging
  44. Refined Chandra analysis of GRB 050509b
  45. GRB050509b, SDSS pre-burst observations
  46. GRB 050509b: Keck/Chandra Cross-Correlation
  47. GRB 050509b: Keck/Chandra Cross-Correlation
  48. Chandra observation of GRB 050509b
  49. GRB 050509b: RAPTOR deep, early limits.
  50. GRB050509B: Optical/Infared observations
  51. GRB 050509b: Swift/UVOT follow-up measurements
  52. GRB 050509b Milagro GeV/TeV Observations
  53. GRB050509B: Optical observations at the Very Large Telescope
  54. GRB 050509b: No Optical Variability in XRT Error Circle
  55. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  56. GRB 050509a: Swift-BAT refined analysis
  57. GRB 050509c: ROTSE-III Optical Limits
  58. GRB 050509B: WSRT Radio Observations
  59. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  60. GRB 050505, early TAROT observation
  61. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  62. GRB 050509b: Further Analysis of Keck LRIS Images
  63. GRB050509c: REM NIR and Optical observations
  64. GRB 050509b: Physical Properties of the Candidate Host galaxy
  65. GRB 050505: SARA Observations
  66. Swift UVOT Follow-up Observations of GRB 050509B
  67. GRB 050509B, Optical Observations
  68. GRB 050509B: Swift/XRT refined analysis
  69. GRB050509a: Swift UVOT observations
  70. GRB 050509b: Optical observations
  71. GRB 050509b: Precision Astrometry
  72. GRB 050509b: Possible Optical Counterpart
  73. Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
  74. GRB 050509A: Optical observations
  75. GRB 050509b: Optical Counterpart Candidate
  76. GRB050509b: Radio Observations
  77. GRB 050509b: PAIRITEL and WIYN Observations
  78. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  79. GRB 050509b: optical observations
  80. GRB 050509b: Swift XRT Position
  81. GRB 050509B: ROTSE-III Optical Limits
  82. Swift Detection of GRB050509b: A short duration burst
  83. GRB 050509a: Swift XRT Position
  84. Swift Detection of the Burst GRB050509
  85. Swift-BAT detection of GRB 050507
  86. GRB 050505: Keck I-band Magnitude
  87. GRB 050505: early time observations
  88. GRB 050505 - Faulkes Telescope North observations
  89. GRB 050502a: Swift XRT Upper Limit
  90. GRB 050505, simultaneous optical observation
  91. GRB050505: Infrared observations
  92. GRB 050505: Further Swift UVOT observations.
  93. GRB050505: AAVSO observations
  94. GRB050416A : 1 GHz limit from GMRT
  95. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  96. GRB 050505 UVOT
  97. GRB050505: Optical Afterglow Candidate
  98. GRB 050505: Swift XRT Position
  99. GRB050505 Swift-BAT refined analysis
  100. GRB 050502a: Optical Observations

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