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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').
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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"

26343 results found.

  1. Fourth Epoch VLA observations of SGR 1806-20
  2. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  3. SGR 1806-20: Temporal and Spectral behavior of radio transient
  4. SGR 1806-20, RHESSI observations of the 041227 giant flare
  5. Second Epoch VLA observations of SGR 1806-20
  6. Second-epoch VLA observations of SGR 1806-20
  7. SGR1806: Detection of a Sudden Ionospheric Disturbance
  8. VLA observations of SGR 1806-20
  9. SGR1806 VLA Observations
  10. VLA observations of SGR 1806-20
  11. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  12. Detection of the SGR 1806-20 giant outburst back-scattered by the
  13. The giant outburst from SGR 1806-20
  14. IPN localization of giant flare from SGR1806-20
  15. Giant flare from SGR 1806-20 detected by INTEGRAL
  16. GRB041219; RXTE ASM Observations
  17. NIR Observations of GRB 041219
  18. GRB041223: decay of the afterglow
  19. GRB041224: ROTSE-III Optical Observations
  20. GRB 041223 Fluence measured by Swift-BAT
  21. GRB041223: optical and NIR observations with REM
  22. Swift-BAT Time History of GRB041219
  23. GRB 041219: TAROT optical observations
  24. GRB 041218: TAROT optical observations
  25. GRB 041223: J-band observations of the afterglow
  26. GRB041223: ROTSE-III Optical Observations
  27. GRB041223: Swift-BAT detection of a bright long burst
  28. GRB 041218: optical observations
  29. Very high activity of SGR 1806-20
  30. GRB 041219: WSRT Radio Afterglow Detection
  31. GRB 041218: Optical observations
  32. GRB 041219 : optical follow-up observations
  33. GRB041220: Swift-BAT burst
  34. Deep RAPTOR observations during GRB 041219
  35. GRB 041218 Optical Observations
  36. GRB 041219 Optical Observations
  37. GRB041219c: Third Burst in One Day from Swift-BAT
  38. GRB041219b: A Swift-BAT burst
  39. GRB 041219 ,optical observation
  40. GRB 041219: Radio Afterglow Detection
  41. GRB 041218 : Radio Observations
  42. GRB 041218: R-band optical observations
  43. GRB041218: optical observations
  44. GRB041219: Confirmed NIR Afterglow
  45. GRB 041218: Optical Observation
  46. GRB 041219: Infrared Afterglow Candidate
  47. GRB 041219: Infrared Afterglow Candidate
  48. GRB041219: P60 Optical Observations
  49. GRB 041219 - A long GRB detected by INTEGRAL
  50. GRB 041217: PROMPT Observations
  51. GRB041218: optical observations
  52. GRB041217: optical limit 30 min after GRB
  53. GRB 041218 - A long GRB detected by integral
  54. GRB041217: NIR and optical observations with REM
  55. GRB041217: P60 Optical Observations
  56. GRB041217: The First GRB Located On-Board Swift
  57. GRB041211: Faulkes Telescope continued optical monitoring
  58. Optical Transient in Lynx not a GRB
  59. Optical transient (GRB?) in Lynx
  60. GRB041211: Continued P60 Observations
  61. GRB041211: RAPTOR observations
  62. GRB041211: Ashra Prototype optical observation
  63. GRB041211, Faulkes Telescope optical observation
  64. GRB041211,optical observation
  65. GRB 041211: Infrared Observations
  66. GRB 041211: Optical follow-up in East Asian region
  67. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  68. GRB041211: P60 optical imaging
  69. GRB970815: Discovery of Optical Afterglow
  70. Triangulation of short GRB 041116 (large error box)
  71. GRB 041006: GETS Optical Afterglow Observation
  72. Summary of the recent bursts from SGR 1806-20
  73. GRB041006, late-time optical photometry
  74. GRB041006: RTT150 Optical Observations
  75. Bright bursts from SGR1806-20
  76. GRB041006: RTT150 Optical Observations
  77. GRB041016,optical observation
  78. GRB 041016:Optical limit during first minute
  79. GRB041015,optical observation
  80. GRB041006: Fading X-ray Afterglow Observed with Chandra
  81. GRB 041015 - A long GRB detected by INTEGRAL
  82. GRB 041006 R observations in Loiano
  83. GRB041006: VLT observations of the afterglow and host galaxy
  84. GRB041006: Optical observations and Potential host galaxy
  85. GRB041006, BVRcIc field calibration
  86. GRB 041006: SARA afterglow observations
  87. GRB041006, optical observation in CrAO
  88. Search for SN light in XRF 040912 with MEGACAM
  89. GRB 041006 Optical afterglow observations
  90. GRB 041006: BR observations with VATT
  91. GRB 041006: Redshift confirmed
  92. GRB041006: Liverpool Telescope optical observations
  93. GRB 041006 : optical follow-up observation at Lulin Observatory
  94. GRB 041006 : Optical follow-up observation at TAROT
  95. GRB041006: Optical photometry and spectroscopy at TNG
  96. GRB 041006: presice astrometry
  97. GRB041006 (= H3570): Chandra Observations In Progress
  98. GRB041006, optical I observation
  99. GRB041006 (=HETE3570): optical observations
  100. ROTSE-IIIa Observations of GRB 041006

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