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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"

28055 results found.

  1. Further VLA observations of SGR 1806-20
  2. SGR 1806-20 and extragalactic short-duration GRBs
  3. Further ATCA observations of SGR 1806-20
  4. Fourth Epoch VLA observations of SGR 1806-20
  5. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  6. ATCA observations of SGR 1806-20
  7. SGR 1806-20, RHESSI observations of the 041227 giant flare
  8. Third epoch observations of SGR 1806-20 with VLA
  9. Second Epoch VLA observations of SGR 1806-20
  10. Second-epoch VLA observations of SGR 1806-20
  11. SGR1806 VLA Observations
  12. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  13. GRB 041217: Optical observations
  14. GRB041228: Swift-BAT detection of a burst
  15. GRB041219; RXTE ASM Observations
  16. NIR Observations of GRB 041219
  17. GRB041226: Swift-BAT detection of a burst
  18. GRB041223: decay of the afterglow
  19. GRB 041224: near-infrared observations with REM
  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. GRB 041219c: PROMPT Observations
  27. GRB041223: Swift-BAT detection of a bright long burst
  28. GRB 041218: optical observations
  29. GRB 041219 : optical follow-up observations
  30. Deep RAPTOR observations during GRB 041219
  31. GRB 041218 Optical Observations
  32. GRB041219: Continued NIR Observations
  33. GRB 041219 ,optical observation
  34. GRB 041219: Radio Afterglow Detection
  35. GRB 041218 : Radio Observations
  36. GRB 041218: R-band optical observations
  37. GRB041218: optical observations
  38. GRB041219: Confirmed NIR Afterglow
  39. Swift-BAT detection of the bright long burst GRB041219
  40. GRB 041219: Infrared Afterglow Candidate
  41. GRB041219, BVRcIc field calibration
  42. GRB 041219: Infrared Afterglow Candidate
  43. GRB041218, BVRcIc field calibration
  44. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  45. GRB 041219 - A long GRB detected by INTEGRAL
  46. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  47. GRB 041217: PROMPT Observations
  48. GRB 041217: LCO40 Optical Observations and Possible Candidates
  49. GRB 041218 - A long GRB detected by integral
  50. GRB041217: NIR and optical observations with REM
  51. GRB041217: Infrared Observations
  52. GRB041217: The First GRB Located On-Board Swift
  53. GRB041211: Faulkes Telescope continued optical monitoring
  54. Optical Transient in Lynx not a GRB
  55. Optical transient (GRB?) in Lynx
  56. GRB041211: RAPTOR observations
  57. GRB041211: Ashra Prototype optical observation
  58. GRB041211, BVRcIc field calibration
  59. GRB041211,optical observation
  60. GRB 041211: Infrared Observations
  61. GRB 041211: KAIT observations
  62. GRB 041211: Optical follow-up in East Asian region
  63. Triangulation of short GRB 041116 (large error box)
  64. GRB 040924: Afterglow Color
  65. GRB 041006: GETS Optical Afterglow Observation
  66. Summary of the recent bursts from SGR 1806-20
  67. GRB 041006: Optical Observations
  68. GRB041006, late-time optical photometry
  69. GRB041006: RTT150 Optical Observations
  70. HST Observations: XRF 040701 and 040812
  71. Bright bursts from SGR1806-20
  72. GRB 041016: BOOTES-2 simultaneous observation
  73. GRB041006: RTT150 Optical Observations
  74. GRB041016,optical observation
  75. GRB 041016: Optical limits
  76. GRB 041016:Optical limit during first minute
  77. GRB 041015: Optical Observations at Rikubetsu
  78. GRB 041016: Optical limit
  79. GRB 041015 R band observations
  80. GRB040924, BVRcIc field calibration
  81. GRB041015,optical observation
  82. GRB041006: Fading X-ray Afterglow Observed with Chandra
  83. GRB 041015 - A long GRB detected by INTEGRAL
  84. GRB041006: VLT observations of the afterglow and host galaxy
  85. GRB041006: Optical observations and Potential host galaxy
  86. GRB041006, BVRcIc field calibration
  87. GRB 040924: VLT spectroscopy
  88. GRB 041006: SARA afterglow observations
  89. GRB041006, optical observation in CrAO
  90. Search for SN light in XRF 040912 with MEGACAM
  91. GRB 041006: BR observations with VATT
  92. GRB 041006: Redshift confirmed
  93. GRB 041006: Radio Observations
  94. GRB 041006 : optical follow-up observation at Lulin Observatory
  95. GRB041006: Optical photometry and spectroscopy at TNG
  96. GRB 041006: presice astrometry
  97. GRB041006, optical I observation
  98. GRB041006 (=HETE3570): optical observations
  99. ROTSE-IIIa Observations of GRB 041006
  100. GRB041006: MASTER optical observations

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