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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"

7293 results found.

  1. GRB 051021: Optical observations and candidate afterglow
  2. GRB051021.63
  3. GRB051021.6: MASTER optical observation
  4. GRB 051016b: Optical limit
  5. Afterglow candidate of GRB 051016B observed at Lulin
  6. GRB 051016b: Gemini Near IR Observations
  7. GRB050805A: Rc optical observations
  8. GRB051008: optical candidate
  9. GRB051011: MASTER optical observation
  10. GRB051008 - Swift UVOT upper limits
  11. GRB 051008, optical observations
  12. GRB 051008: Swift UVOT Candidate
  13. grb test
  14. GRB050925: Faulkes Telescope North R-band limit
  15. GRB 050911, optical content of Swift/XRT error box
  16. GRB050911: Swift-XRT position
  17. GRB050908 : Swift-XRT refined analysis
  18. GRB 050908: Optical observations
  19. Gemini Spectroscopy of GRB 050908
  20. GRB 050908: P60 Confirmation of Optical Afterglow
  21. GRB 050908: Optical Observations
  22. GRB 050904: Subaru Optical Spectroscopy
  23. GRB 050906: Swift-BAT refined analysis
  24. GRB 050904: Keck I-band Imaging
  25. GRB 050904: TAROT optical measurements
  26. GRB 050827: Optical Limit
  27. GRB 050826 : Lulin R band observation
  28. GRB 050826: Optical Candidate
  29. GRB050824: MASTER final analysis of the OT observations
  30. GRB050824, I-band imaging
  31. GRB 050824: XRT refined analysis and possible afterglow detection
  32. GRB 050824: BAT refined analysis of a soft weak burst
  33. GRB050824: MASTER:OT decay
  34. GRB 050824 optical candidate
  35. GRB050814: P60 Optical Afterglow Candidate
  36. GRB 050813: Non-fading of afterglow candidate
  37. GRB050803: CrAO optical observations, no OT candidate
  38. GRB050802: TNG optical observations
  39. GRB 050803: RTT150 optical observations
  40. GRB050803: CrAO optical observations, possible OT candidate
  41. GRB 050803, optical observations
  42. GRB 050802: Swift/UVOT optical and UV detections
  43. GRB050801: Optical photometry and decay index
  44. GRB 050730, SMARTS optical/IR afterglow observations
  45. GRB050730: Liverpool Telescope optical observations
  46. GRB 050730, optical candidate
  47. GRB 050721a: Optical Observations
  48. GRB 050714a: Refined XRT analysis and afterglow confirmation
  49. GRB 050716; J-band observations
  50. GRB 050716 - UKIRT identification of candidate afterglow
  51. GRB 050716: Refined XRT analysis.
  52. GRB050716: Faulkes North Telescope observation
  53. GRB 050714B: refined XRT analysis
  54. GRB 050714B: candidate afterglow does not fade
  55. GRB 050709: optical afterglow candidate
  56. GRB 050714, R-band candidate
  57. GRB 050709: Spectroscopy
  58. GRB050713B: Faulkes North Telescope observation
  59. RBO RI observations of GRB 050713A
  60. GRB050709: Candidate X-ray Afterglow from Chandra
  61. GRB 050713: ARC NIR Detections and Identification of Fading
  62. GRB050712: UVOT candidate optical counterpart
  63. GRB 050626: Swift XRT observations
  64. GRB 050607: MDM Observations
  65. GRB 050603: Swift XRT Position
  66. GRB050528: BOOTES optical candidate (retraction)
  67. GRB050528: BOOTES optical candidate
  68. Possible GRB050528: no candidate from Liverpool Telescope
  69. GRB050525: Super-LOTIS observations
  70. GRB 050525a: Gemini/GMOS Spectra
  71. GRB050306: optical afterglow not confirmed
  72. GRB050525: Optical observations
  73. GRB 050525: Optical observation
  74. XRF050522: NIR observations of XRT candidate
  75. XRF 050522: Swift XRT refined analysis
  76. XRF050522: Optical Observations
  77. GRB050520: Liverpool Telescope follow-up
  78. XRF 050509C: REM NIR and Optical refined analysis
  79. GRB 050504: Swift XRT afterglow candidate has faded
  80. Chandra observation of GRB 050509b
  81. GRB 050509b: RAPTOR deep, early limits.
  82. GRB 050509b: Further Analysis of Keck LRIS Images
  83. GRB 050509b: Physical Properties of the Candidate Host galaxy
  84. GRB 050509B, Optical Observations
  85. GRB 050509b: Optical observations
  86. GRB 050509b: Optical Counterpart Candidate
  87. GRB 050505 - Faulkes Telescope North observations
  88. GRB050505: Infrared observations
  89. GRB050505: AAVSO observations
  90. GRB 050505: Keck absorption spectrum and redshift (z=4.27)
  91. GRB050505: Optical Afterglow Candidate
  92. GRB 050416b:Swift XRT afterglow upper limits
  93. GRB 050416b:Swift XRT afterglow upper limits
  94. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  95. GRB050502b: Afterglow Confirmation
  96. GRB050502A: Optical Observations
  97. Swift UVOT refined analysis
  98. GRB 050502: Confirmed variability of the afterglow candidate +
  99. GRB050502 - Correction on the Optical Candidate from the Liverpool
  100. GRB050502 - Optical Candidate from the Liverpool Telescope

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