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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"

28051 results found.

  1. SGR 1806-20: Low frequency GMRT results; submission to GCN circulars
  2. ATCA observations of SGR 1806-20
  3. SGR 1806-20, RHESSI observations of the 041227 giant flare
  4. Third epoch observations of SGR 1806-20 with VLA
  5. Second Epoch VLA observations of SGR 1806-20
  6. Second-epoch VLA observations of SGR 1806-20
  7. SGR1806 VLA Observations
  8. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  9. GRB 041217: Optical observations
  10. GRB041228: Swift-BAT detection of a burst
  11. GRB041219; RXTE ASM Observations
  12. NIR Observations of GRB 041219
  13. GRB041226: Swift-BAT detection of a burst
  14. GRB041223: decay of the afterglow
  15. GRB 041224: near-infrared observations with REM
  16. GRB 041223 Fluence measured by Swift-BAT
  17. GRB041223: optical and NIR observations with REM
  18. Swift-BAT Time History of GRB041219
  19. GRB 041219: TAROT optical observations
  20. GRB 041218: TAROT optical observations
  21. GRB 041223: J-band observations of the afterglow
  22. GRB 041219c: PROMPT Observations
  23. GRB041223: Swift-BAT detection of a bright long burst
  24. GRB 041218: optical observations
  25. GRB 041219 : optical follow-up observations
  26. Deep RAPTOR observations during GRB 041219
  27. GRB 041218 Optical Observations
  28. GRB041219: Continued NIR Observations
  29. GRB 041219 ,optical observation
  30. GRB 041219: Radio Afterglow Detection
  31. GRB 041218 : Radio Observations
  32. GRB 041218: R-band optical observations
  33. GRB041218: optical observations
  34. GRB041219: Confirmed NIR Afterglow
  35. Swift-BAT detection of the bright long burst GRB041219
  36. GRB 041219: Infrared Afterglow Candidate
  37. GRB041219, BVRcIc field calibration
  38. GRB 041219: Infrared Afterglow Candidate
  39. GRB041218, BVRcIc field calibration
  40. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  41. GRB 041219 - A long GRB detected by INTEGRAL
  42. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  43. GRB 041217: PROMPT Observations
  44. GRB 041217: LCO40 Optical Observations and Possible Candidates
  45. GRB 041218 - A long GRB detected by integral
  46. GRB041217: NIR and optical observations with REM
  47. GRB041217: Infrared Observations
  48. GRB041217: The First GRB Located On-Board Swift
  49. GRB041211: Faulkes Telescope continued optical monitoring
  50. Optical Transient in Lynx not a GRB
  51. Optical transient (GRB?) in Lynx
  52. GRB041211: RAPTOR observations
  53. GRB041211: Ashra Prototype optical observation
  54. GRB041211, BVRcIc field calibration
  55. GRB041211,optical observation
  56. GRB 041211: Infrared Observations
  57. GRB 041211: KAIT observations
  58. GRB 041211: Optical follow-up in East Asian region
  59. Triangulation of short GRB 041116 (large error box)
  60. GRB 040924: Afterglow Color
  61. GRB 041006: GETS Optical Afterglow Observation
  62. Summary of the recent bursts from SGR 1806-20
  63. GRB 041006: Optical Observations
  64. GRB041006, late-time optical photometry
  65. GRB041006: RTT150 Optical Observations
  66. HST Observations: XRF 040701 and 040812
  67. Bright bursts from SGR1806-20
  68. GRB 041016: BOOTES-2 simultaneous observation
  69. GRB041006: RTT150 Optical Observations
  70. GRB041016,optical observation
  71. GRB 041016: Optical limits
  72. GRB 041016:Optical limit during first minute
  73. GRB 041015: Optical Observations at Rikubetsu
  74. GRB 041016: Optical limit
  75. GRB 041015 R band observations
  76. GRB040924, BVRcIc field calibration
  77. GRB041015,optical observation
  78. GRB041006: Fading X-ray Afterglow Observed with Chandra
  79. GRB 041015 - A long GRB detected by INTEGRAL
  80. GRB041006: VLT observations of the afterglow and host galaxy
  81. GRB041006: Optical observations and Potential host galaxy
  82. GRB041006, BVRcIc field calibration
  83. GRB 040924: VLT spectroscopy
  84. GRB 041006: SARA afterglow observations
  85. GRB041006, optical observation in CrAO
  86. Search for SN light in XRF 040912 with MEGACAM
  87. GRB 041006: BR observations with VATT
  88. GRB 041006: Redshift confirmed
  89. GRB 041006: Radio Observations
  90. GRB 041006 : optical follow-up observation at Lulin Observatory
  91. GRB041006: Optical photometry and spectroscopy at TNG
  92. GRB 041006: presice astrometry
  93. GRB041006, optical I observation
  94. GRB041006 (=HETE3570): optical observations
  95. ROTSE-IIIa Observations of GRB 041006
  96. GRB041006: MASTER optical observations
  97. GRB041006,optical observation
  98. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  99. GRB041006: Fading of optical afterglow candidate
  100. GRB 041006: Optical afterglow candidate

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