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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"

45629 results found.

  1. GRB 050906: MARGE Optical Limits
  2. GRB 050906: Swift-BAT refined analysis
  3. GRB 050906: Swift XRT upper limit
  4. GRB 050906: Radio Observations
  5. GRB 050904: Keck I-band Imaging
  6. GRB050906: P60 Observations
  7. GRB 050904: more VLT NIR observations
  8. GRB 050904: BOOTES early R-band observation
  9. GRB 050904: Did SWIFT/XRT see the prompt GRB emission ?
  10. GRB 050906: Bright galaxy in BAT error box
  11. GRB 050906: Swift/BAT Detection of a possible burst
  12. GRB 050904: More SOAR
  13. GRB 050904: photometric redshift
  14. GRB 050904: Swift/UVOT observations
  15. GRB 050904: Afterglow Astrometry
  16. GRB 050904: NIR object inside the XRT error box
  17. GRB 050904: early Swift XRT analysis results
  18. GRB 050904: SOAR YJ and PROMPT Ic Observations
  19. GRB 050904: BAT refined analysis of partial data set
  20. GRB 050904: TAROT optical measurements
  21. GRB050904: Optical Observations
  22. GRB 050904: Environmental Constraints
  23. GRB 050904: Possible High-Redshift GRB
  24. GRB 050904: SOAR/PROMPT Observations
  25. GRB050904: P60 Observations
  26. GRB 050904: TAROT optical limits
  27. GRB050904: Swift-BAT detection of a probable burst
  28. Swift-BAT triggers 153461-153465 are not GRBs
  29. Retraction of Swift-BAT trigger #153355
  30. GRB 050824: MDM Observations
  31. GRB 050827: Swift XRT preliminary analysis results
  32. IBAS Alerts 2641 and 2642: not a real GRB
  33. Swift Trigger #152652 is not a GRB
  34. GRB 050827 : OSN 1.5m optical observations
  35. GRB 050827: P200 NIR Observations
  36. GRB050827: Swift/UVOT upper limits
  37. GRB 050827: Optical Limit
  38. GRB 050827: XRT possible afterglow detection
  39. GRB 050826 : Lulin R band observation
  40. GRB050824: Maidanak optical limits
  41. GRB050820A: RTT150 optical observations
  42. GRB050827: RTT150 optical observations
  43. GRB 050827: Swift-BAT refined analysis
  44. GRB050827: Swift-BAT detection of a burst
  45. Subaru Observations of GRB050724
  46. GRB 050826: Optical Candidate
  47. GRB050824, HETE-2 Observation
  48. GRB 050826: Swift XRT preliminary analysis results
  49. GRB 050826: BAT refined analysis
  50. GRB050826: Swift/UVOT early upper limits
  51. GRB050824: First 2 hours of power low optical decay?
  52. GRB 050826: Swift XRT position
  53. GRB050826: Swift-BAT detection of a long burst
  54. GRB050824: MASTER final analysis of the OT observations
  55. Possible GRB050825:MASTER optical observations
  56. Swift-BAT trigger 152038 is definitely not a GRB
  57. GRB050824: CORRECTION to UVOT observing times
  58. Swift-BAT trigger 152038 is probably not a GRB
  59. GRB050824: Swift/UVOT detection of fading afterglow
  60. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  61. GRB050824, I-band imaging
  62. GRB050824: Radio Observations
  63. GRB 050824: Spectroscopic redshift from the VLT
  64. GRB 050822: refined XRT analysis
  65. GRB 050824: XRT refined analysis and possible afterglow detection
  66. GRB 050824: BAT refined analysis of a soft weak burst
  67. GRB050824: MASTER:OT decay
  68. GRB050824: MASTER observation OT
  69. GRB050805a: MASTER optical candidat
  70. GRB 050824: ROTSE-III Optical Limits
  71. GRB050824: Swift-BAT detection of a burst
  72. GRB 050824 optical candidate
  73. GRB050820A: RTT150 optical observations
  74. GRB050820a: PROMPT RcIc Observations
  75. GRB050815: Maidanak optical observation
  76. XRF050509c: Radio upper limits from GMRT
  77. VLT/UVES spectroscopy of GRB050820
  78. GRB050822: Swift/UVOT upper limits
  79. GRB 050820A BAT observations of second, larger episode of emission
  80. GRB050813: Maidanak I-band observations
  81. GRB 050822: Swift-BAT refined analysis
  82. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  83. GRB050820B at FRAM
  84. GRB050820A: RTT150 optical observations
  85. GRB 050820a - corrections to GCN 3846
  86. Swift/UVOT UV Photometry of GRB 050820B
  87. GRB 050822: ROTSE-III Prompt Optical Limits
  88. GRB 050822: Swift detection of a long burst
  89. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  90. GRB050820A: Radio Observation
  91. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  92. GRB050820a BVRcIc field photometry
  93. GRB050820B XMM-Newton observation
  94. GRB 050820a: NIR Observations by WIRO
  95. GRB 050820B: Swift XRT position
  96. GRB050820B: Planned XMM-Newton observation
  97. GRB050820B: Refined analysis of the Swift-BAT burst
  98. GRB050820B: BAT-Swift detection of a bright GRB
  99. Swift/UVOT photometry of GRB050820
  100. GRB050820: refined XRT analysis

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