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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"

18336 results found.

  1. GRB 050525: observatons of the optical afterglow
  2. GRB050525: ROTSE-III Refined Analysis
  3. GRB 050525: Swift Detection of a Bright, Possibly Short Burst
  4. XRF050522: Radio Observations
  5. Swift/UVOT observation of XRF 050522
  6. GRB 050509A: Further I-band imaging
  7. GRB050522,optical observation
  8. GRB050520,optical observation
  9. XRF 050522: Continued NIR P200 Monitoring
  10. GRB050509b: optical observations
  11. Recent GRB BVRcIc field photometry
  12. GRB050520: Radio Observations
  13. XRF 050522: Swift XRT observation
  14. XRF050522, BVRcIc field photometry
  15. XRF050522: Optical Observations
  16. XRF050522: Near-infrared Observations
  17. GRB 050520: VLT/ULTRACAM observations
  18. XRF050509c: Radio Observations
  19. GRB 050520: P200 Observations
  20. GRB 050520: TAROT optical limit
  21. GRB 050520: VLT/ULTRACAM observations
  22. GRB 050509B: Subaru Optical Observations
  23. GRB050502b: Early Observation
  24. GRB050509b, Bok telescope B-band imaging
  25. GRB050509b, SDSS pre-burst observations
  26. GRB 050509b: Keck/Chandra Cross-Correlation
  27. GRB 050509b: Keck/Chandra Cross-Correlation
  28. Chandra observation of GRB 050509b
  29. GRB050509B: Optical observations at the Very Large Telescope
  30. GRB 050509b: No Optical Variability in XRT Error Circle
  31. GRB 050509c: ROTSE-III Optical Limits
  32. GRB 050509B: WSRT Radio Observations
  33. GRB 050505, early TAROT observation
  34. GRB050509c (=H3751): An X-Ray Flash Localized By HETE
  35. GRB050509c: REM NIR and Optical observations
  36. GRB 050505: SARA Observations
  37. GRB 050509b: Optical observations
  38. GRB 050509b: Possible Optical Counterpart
  39. GRB 050509A: Optical observations
  40. GRB050509b: Radio Observations
  41. Swift Detection of GRB050509b: A short duration burst
  42. Swift Detection of the Burst GRB050509
  43. GRB 050505, simultaneous optical observation
  44. GRB050505: AAVSO observations
  45. GRB050416A : 1 GHz limit from GMRT
  46. GRB050505: Optical Afterglow Candidate
  47. GRB 050505: Swift XRT Position
  48. GRB 050416b:Swift XRT afterglow upper limits
  49. GRB 050416b:Swift XRT afterglow upper limits
  50. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  51. GRB050502b: Afterglow Confirmation
  52. GRB050502: P200 Observations (Correction)
  53. GRB050502: P200 Observations
  54. Swift UVOT observation of GRB 050504
  55. GRB050504: P60 Observations
  56. GRB (?) 050504: IR Observations, Intriguing Source
  57. GRB 050502b, Optical observations
  58. GRB050502a: P60 Observations (Correction)
  59. GRB050502a: P60 Observations
  60. GRB050502B Swift-BAT refined analysis
  61. GRB050502B: I band source in XRT error circle
  62. Swift UVOT refined analysis
  63. GRB050502B: Optical Limits from ANU 1m
  64. GRB 050502: ROTSE-III Detection of Possible Counterpart
  65. Swift/BAT possible detection of a weak burst GRB050430
  66. GRB050416a: Radio Detection
  67. Swift Detection of GRB 050422
  68. GRB 050421: SLOTIS observations
  69. GRB 050421: Further Analysis of IR imaging
  70. GRB050421: Radio Observations
  71. GRB050421: Radio Observations
  72. GRB 050421: Swift-UVOT observation
  73. GRB 050421: IR Observations
  74. GRB050421
  75. GRB 050421: NIR observations
  76. GRB050421: P60 Observations
  77. GRB 050421: BOOTES-2 simultaneous optical observations
  78. GRB 050416b: Tentative Swift XRT Position
  79. GRB 050315: potential host galaxy
  80. GRB050326: analysis of the XMM-Newton observation
  81. GRB050418: Null Optical Observations
  82. GRB050416A, optical observations
  83. GRB 050416: Mitsume optical observation
  84. GRB050416B: IR observations
  85. GRB 050416: Swift/UVOT refined analysis
  86. GRB050412: Radio Observations
  87. GRB 050416: Swift/UVOT detection of afterglow emission
  88. GRB 050416,optical observation
  89. GRB050416: P200 NIR Observations
  90. GRB 050416: Radio observations
  91. Swift BAT/XRT Detection of GRB 050416
  92. GRB 050412: Subaru observations
  93. GRB050408: optical observation
  94. GRB 050408: Kuiper 1.5m observations
  95. GRB 050412: optical observations
  96. GRB 050412: Early Optical/Ultraviolet Observations with
  97. GRB 050408: SDSS Field Calibration
  98. GRB050412: P60 Observations
  99. Swift-BAT Detection of GRB 050412: A Bright, Long Burst
  100. GRB 050412: IR and Optical observations

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