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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"

45645 results found.

  1. GRB050908 : Swift-XRT refined analysis
  2. GRB 050908: Swift-BAT refined analysis
  3. GRB 050908: Optical observations
  4. Gemini Spectroscopy of GRB 050908
  5. GRB 050908: spectroscopic redshift
  6. GRB 050908: Prompt PROMPT Observations
  7. GRB 050908 : Swift XRT position
  8. GRB 050908: KAIT observations
  9. GRB 050908: P60 Confirmation of Optical Afterglow
  10. GRB 050908: Optical Observations
  11. GRB 050908: Swift detection of a burst
  12. Swift trigger 154073 is not a GRB
  13. GRB 050906: Optical observations at the Very Large Telescope
  14. GRB050904: CrAO optical observations
  15. GRB 050904 BAT refined analysis of complete data set
  16. GRB 050904: Subaru Optical Spectroscopy
  17. GRB 050906: MARGE Optical Limits
  18. GRB 050906: Swift-BAT refined analysis
  19. GRB 050906: Swift XRT upper limit
  20. GRB 050906: Radio Observations
  21. GRB 050904: Keck I-band Imaging
  22. GRB050906: P60 Observations
  23. GRB 050904: more VLT NIR observations
  24. GRB 050904: BOOTES early R-band observation
  25. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  26. GRB 050906: Bright galaxy in BAT error box
  27. GRB 050906: Swift/BAT Detection of a possible burst
  28. GRB 050904: More SOAR
  29. GRB 050904: photometric redshift
  30. GRB 050904: Swift/UVOT observations
  31. GRB 050904: Afterglow Astrometry
  32. GRB 050904: NIR object inside the XRT error box
  33. GRB 050904: early Swift XRT analysis results
  34. GRB 050904: SOAR YJ and PROMPT Ic Observations
  35. GRB 050904: BAT refined analysis of partial data set
  36. GRB 050904: TAROT optical measurements
  37. GRB050904: Optical Observations
  38. GRB 050904: Environmental Constraints
  39. GRB 050904: Possible High-Redshift GRB
  40. GRB 050904: SOAR/PROMPT Observations
  41. GRB050904: P60 Observations
  42. GRB 050904: TAROT optical limits
  43. GRB050904: Swift-BAT detection of a probable burst
  44. Swift-BAT triggers 153461-153465 are not GRBs
  45. Retraction of Swift-BAT trigger #153355
  46. GRB 050824: MDM Observations
  47. GRB 050827: Swift XRT preliminary analysis results
  48. IBAS Alerts 2641 and 2642: not a real GRB
  49. Swift Trigger #152652 is not a GRB
  50. GRB 050827 : OSN 1.5m optical observations
  51. GRB 050827: P200 NIR Observations
  52. GRB050827: Swift/UVOT upper limits
  53. GRB 050827: Optical Limit
  54. GRB 050827: XRT possible afterglow detection
  55. GRB 050826 : Lulin R band observation
  56. GRB050824: Maidanak optical limits
  57. GRB050820A: RTT150 optical observations
  58. GRB050827: RTT150 optical observations
  59. GRB 050827: Swift-BAT refined analysis
  60. GRB050827: Swift-BAT detection of a burst
  61. Subaru Observations of GRB050724
  62. GRB 050826: Optical Candidate
  63. GRB050824, HETE-2 Observation
  64. GRB 050826: Swift XRT preliminary analysis results
  65. GRB 050826: BAT refined analysis
  66. GRB050826: Swift/UVOT early upper limits
  67. GRB050824: First 2 hours of power low optical decay?
  68. GRB 050826: Swift XRT position
  69. GRB050826: Swift-BAT detection of a long burst
  70. GRB050824: MASTER final analysis of the OT observations
  71. Possible GRB050825:MASTER optical observations
  72. Swift-BAT trigger 152038 is definitely not a GRB
  73. GRB050824: CORRECTION to UVOT observing times
  74. Swift-BAT trigger 152038 is probably not a GRB
  75. GRB050824: Swift/UVOT detection of fading afterglow
  76. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  77. GRB050824, I-band imaging
  78. GRB050824: Radio Observations
  79. GRB 050824: Spectroscopic redshift from the VLT
  80. GRB 050822: refined XRT analysis
  81. GRB 050824: XRT refined analysis and possible afterglow detection
  82. GRB 050824: BAT refined analysis of a soft weak burst
  83. GRB050824: MASTER:OT decay
  84. GRB050824: MASTER observation OT
  85. GRB050805a: MASTER optical candidat
  86. GRB 050824: ROTSE-III Optical Limits
  87. GRB050824: Swift-BAT detection of a burst
  88. GRB 050824 optical candidate
  89. GRB050820A: RTT150 optical observations
  90. GRB050820a: PROMPT RcIc Observations
  91. GRB050815: Maidanak optical observation
  92. XRF050509c: Radio upper limits from GMRT
  93. VLT/UVES spectroscopy of GRB050820
  94. GRB050822: Swift/UVOT upper limits
  95. GRB 050820A BAT observations of second, larger episode of emission
  96. GRB050813: Maidanak I-band observations
  97. GRB 050822: Swift-BAT refined analysis
  98. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  99. GRB050820B at FRAM
  100. GRB050820A: RTT150 optical observations

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