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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"
  1. GRB 070808: Swift XRT refined analysis
  2. GRB 070808, Swift-BAT refined analysis
  3. GRB 070808: OPTIMA-Burst optical upper limit
  4. GRB 070808: Xinglong TNT optical Upper Limit
  5. GRB070808: Optical observations with KANATA
  6. GRB070808 - SDSS Pre-Burst Observations
  7. GRB 070808: ROTSE-III Optical Limits
  8. GRB 070808: Swift detection of a burst
  9. GRB061121A: PROMPT Observations
  10. GRB070805 XRT and UVOT afterglow candidate
  11. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  12. GRB070612A: Radio upper limit from GMRT
  13. GRB 070721B: correct afterglow position
  14. Swift/UVOT observations of GRB070805
  15. GRB 070805, Swift-BAT refined analysis
  16. GRB 070805: Swift XRT initial analysis.
  17. GRB 070805: Swift/UVOT initial analysis
  18. GRB 070805: Swift detection of a burst
  19. UVOT observations of SAXJ1810.8-2609
  20. Swift detection of a outburst from SAX J1810.8-2609
  21. VLA non-detection of GRB 070721B
  22. GRB 070802: REM optical observations
  23. GRB 070724B: Swift-XRT afterglow confirmation
  24. GRB 070802: Swift-XRT refined analysis
  25. GRB070802: Swift/UVOT upper limits
  26. GRB 070802: Confirmation of the optical afterglow
  27. GRB 070802, Swift-BAT refined analysis
  28. GRB 070802: VLT redshift
  29. GRB 070802: refined Swift XRT position
  30. GRB 070802: V-band detection of the candidate afterglow
  31. GRB 070802: LCO I-band candidate
  32. GRB 070802: GROND J band candidate
  33. GRB 070802: LCO optical observations
  34. GRB 070802: Swift detection of a burst
  35. GRB 070731, Swift-BAT refined analysis
  36. Konus-A observation of GRB 070729
  37. Swift/UVOT detection of GRB070714B
  38. AGILE-ACS position for the SGR 1806-20 July 27 burst
  39. GRB 070724B: pseudo-z ~ 1.10 from prompt emission spectrum
  40. GRB 070729: LCO optical imaging
  41. VLA upper limit on short hard burst GRB 070714B
  42. Intense burst from SGR 1806-20 detected on July 27
  43. GRB070729: Swift/UVOT upper limits
  44. GRB 070729: Swift-XRT refined analysis
  45. GRB 070729, Swift-BAT refined analysis
  46. GRB 070729: Magellan NIR Observations
  47. GRB 070724B: P60 Observations
  48. GRB 070729: Swift detection of a short hard burst
  49. GRB 070724B: Swift/UVOT Upper limits
  50. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  51. GRB 070724B: Swift-XRT afterglow likely candidate
  52. GRB 070721A: optical observations
  53. GRB 070724A: further VLT observations
  54. GRB 070724B: Suzaku WAM observation of the prompt emission
  55. Konus-Wind observation of GRB 070724B
  56. GRB 070724B: Analysis of AGILE gamma-ray data
  57. GRB 070724B: Swift-XRT afterglow candidates
  58. GRB 070724b: First Gamma Ray Burst Localization by SuperAGILE onboard
  59. Four radio sources in Swift-XRT error box of GRB 070724
  60. GRB 070724: optical observations
  61. GRB070724: Host galaxy redshift
  62. GRB 070724: P60 and Gemini Observations
  63. GRB 060814 - Keck host detection and redshift
  64. GRB 070724: IR observations
  65. GRB 070724: Closer association with DSS source
  66. Swift/UVOT refined analysis of GRB070724
  67. GRB 070724: Swift-XRT Team refined analysis
  68. GRB 070724: Pre-Imaging Shows a Source in the XRT Error Circle
  69. Short-Hard GRB070714B: PROMPT Observations
  70. GRB 070724, Swift-BAT refined analysis of a short burst
  71. GRB 070721B: further observations and analysis
  72. GRB 070724: Swift detection of a burst
  73. GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
  74. GRB 070714B: Keck observations
  75. GRB 070721B: optical observations and proposed redshift
  76. Swift/UVOT observations of GRB070721B optical afterglow.
  77. GRB 070721B, Further Swift-BAT refined analysis
  78. Swift/UVOT Observations of GRB070721A
  79. GRB 070721B : Faulkes Telescope South observations
  80. GRB 070721B: Swift-XRT refined analysis
  81. GRB 070721A : Faulkes Telescope South optical limit
  82. GRB 070721A: Swift/XRT refined analysis
  83. GRB 070721B, Swift-BAT refined analysis
  84. GRB 070721A, Swift-BAT refined analysis
  85. GRB070721B: A bright UVOT candidate
  86. GRB 070721B: Swift detection of a burst
  87. GRB 070721: Swift detection of a possible burst
  88. GRB 070714B: Swift/BAT and Suzaku/WAM joint spectral analysis
  89. GRB 070714B : Suzaku WAM observation of the prompt emission
  90. GRB 070714A: Swift-BAT T_zero
  91. GRB070714B: TNG NIR observations
  92. Erratum : Suzaku WAM observation of GRB 070704
  93. GRB 070714A: Swift/UVOT Upper limits
  94. GRB 070714B: Swift/UVOT Upper Limits
  95. GRB 070714B: Swift-BAT spectral lag for the SHB
  96. GRB 070714B: confirmation of optical afterglow
  97. GRB 070616: No Evidence for I Band Afterglow
  98. GRB 070714A: Swift XRT refined analysis
  99. GRB070714B: Swift-XRT refined analysis
  100. GRB 070707: Swift-XRT follow-up observations

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