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

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