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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"

32489 results found.

  1. XRF050522: NIR observations of XRT candidate
  2. XRF 050522: Swift XRT refined analysis
  3. XRF050522: Radio Observations
  4. Swift/UVOT observation of XRF 050522
  5. GRB 050509A: Further I-band imaging
  6. XRF 050522: Continued NIR P200 Monitoring
  7. RBO Observations of GRB050522
  8. GRB050520: Radio Observations
  9. XRF 050522: Swift XRT observation
  10. XRF050522, BVRcIc field photometry
  11. XRF 050522 : Lulin observations
  12. XRF050522: Optical Observations
  13. XRF050522: Near-infrared Observations
  14. XRF 050522: KAIT observations
  15. GRB 050520: VLT/ULTRACAM observations
  16. Swift UVOT Observations of GRB 050520
  17. GRB 050520: Swift XRT refined analysis
  18. XRF050509C: Chandra Afterglow Detection
  19. XRF 050509c: Swift XRT Upper Limit
  20. XRF050509c: Radio Observations
  21. RBO Observations of GRB050520
  22. GRB 050520: P200 Observations
  23. GRB050520: Liverpool Telescope follow-up
  24. GRB 050520: TAROT optical limit
  25. GRB 050520: Swift XRT position
  26. GRB 050520: VLT/ULTRACAM observations
  27. GRB 050520: OSN optical observations
  28. No Swift-BAT Lightcurves in real-time for next 3 weeks
  29. Swift-BAT trigger 122203 is not a real GRB
  30. XRF 050509C: REM NIR and Optical refined analysis
  31. GRB 050504: Swift XRT afterglow candidate has faded
  32. XRF 050509c optical afterglow
  33. GRB 050509B and short GRB-SN association? (corrected)
  34. GRB 050509B and short GRB-SN association?
  35. GRB 050509B: Subaru Optical Observations
  36. GRB050502b: Early Observation
  37. GRB050509b, Bok telescope B-band imaging
  38. Refined Chandra analysis of GRB 050509b
  39. GRB050509b, SDSS pre-burst observations
  40. GRB 050509b: Keck/Chandra Cross-Correlation
  41. Chandra observation of GRB 050509b
  42. GRB 050509b: RAPTOR deep, early limits.
  43. GRB050509B: Optical/Infared observations
  44. GRB 050509b: Swift/UVOT follow-up measurements
  45. GRB 050509b Milagro GeV/TeV Observations
  46. GRB050509B: Optical observations at the Very Large Telescope
  47. GRB 050509b: No Optical Variability in XRT Error Circle
  48. GRB050416: Afterglow detection at 188 nm with Swift UVOT
  49. GRB 050509a: Swift-BAT refined analysis
  50. GRB 050509c: ROTSE-III Optical Limits
  51. GRB 050509B: WSRT Radio Observations
  52. GRB050509c: REM NIR and Optical observations (errata corrige to GCN 3400)
  53. GRB 050505, early TAROT observation
  54. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  55. GRB 050509b: Further Analysis of Keck LRIS Images
  56. GRB 050509b: Physical Properties of the Candidate Host galaxy
  57. GRB 050505: SARA Observations
  58. Swift UVOT Follow-up Observations of GRB 050509B
  59. GRB 050509B, Optical Observations
  60. GRB 050509B: Swift/XRT refined analysis
  61. GRB050509a: Swift UVOT observations
  62. GRB 050509b: Optical observations
  63. GRB 050509b: Precision Astrometry
  64. GRB 050509b: Possible Optical Counterpart
  65. GRB 050509A: Optical observations
  66. GRB 050509b: Optical Counterpart Candidate
  67. GRB050509b: Radio Observations
  68. GRB 050509b: Swift-BAT refined analysis of the short hard burst
  69. GRB 050509b: optical observations
  70. GRB 050509b: Swift XRT Position
  71. GRB 050509B: ROTSE-III Optical Limits
  72. GRB 050509a: Swift XRT Position
  73. GRB 050505: Keck I-band Magnitude
  74. GRB 050505: early time observations
  75. GRB 050502a: Swift XRT Upper Limit
  76. GRB 050505, simultaneous optical observation
  77. GRB050505: Infrared observations
  78. GRB 050505: Further Swift UVOT observations.
  79. GRB050505: AAVSO observations
  80. GRB050416A : 1 GHz limit from GMRT
  81. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  82. GRB 050505 UVOT
  83. GRB050505: Optical Afterglow Candidate
  84. GRB 050505: Swift XRT Position
  85. GRB050505 Swift-BAT refined analysis
  86. GRB 050502a: Optical Observations
  87. GRB 050416b:Swift XRT afterglow upper limits
  88. GRB 050416b:Swift XRT afterglow upper limits
  89. Swift-BAT detection of GRB050505
  90. GRB 050504: Swift XRT position
  91. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  92. GRB050502b: Afterglow Confirmation
  93. GRB050502: P200 Observations (Correction)
  94. GRB050502: P200 Observations
  95. GRB 050504 : R band observation at Lulin observatory
  96. Swift UVOT observation of GRB 050504
  97. GRB 050504, R band Observations
  98. GRB050504: P60 Observations
  99. GRB 050502b, Optical observations
  100. GRB050502a: P60 Observations (Correction)

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