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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"

28046 results found.

  1. Second-epoch VLA observations of SGR 1806-20
  2. SGR1806 VLA Observations
  3. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  4. GRB 041217: Optical observations
  5. GRB041228: Swift-BAT detection of a burst
  6. GRB041219; RXTE ASM Observations
  7. NIR Observations of GRB 041219
  8. GRB041226: Swift-BAT detection of a burst
  9. GRB041223: decay of the afterglow
  10. GRB 041224: near-infrared observations with REM
  11. GRB 041223 Fluence measured by Swift-BAT
  12. GRB041223: optical and NIR observations with REM
  13. Swift-BAT Time History of GRB041219
  14. GRB 041219: TAROT optical observations
  15. GRB 041218: TAROT optical observations
  16. GRB 041223: J-band observations of the afterglow
  17. GRB 041219c: PROMPT Observations
  18. GRB041223: Swift-BAT detection of a bright long burst
  19. GRB 041218: optical observations
  20. GRB 041219 : optical follow-up observations
  21. Deep RAPTOR observations during GRB 041219
  22. GRB 041218 Optical Observations
  23. GRB041219: Continued NIR Observations
  24. GRB 041219 ,optical observation
  25. GRB 041219: Radio Afterglow Detection
  26. GRB 041218 : Radio Observations
  27. GRB 041218: R-band optical observations
  28. GRB041218: optical observations
  29. GRB041219: Confirmed NIR Afterglow
  30. Swift-BAT detection of the bright long burst GRB041219
  31. GRB 041219: Infrared Afterglow Candidate
  32. GRB041219, BVRcIc field calibration
  33. GRB 041219: Infrared Afterglow Candidate
  34. GRB041218, BVRcIc field calibration
  35. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  36. GRB 041219 - A long GRB detected by INTEGRAL
  37. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  38. GRB 041217: PROMPT Observations
  39. GRB 041217: LCO40 Optical Observations and Possible Candidates
  40. GRB 041218 - A long GRB detected by integral
  41. GRB041217: NIR and optical observations with REM
  42. GRB041217: Infrared Observations
  43. GRB041217: The First GRB Located On-Board Swift
  44. GRB041211: Faulkes Telescope continued optical monitoring
  45. Optical Transient in Lynx not a GRB
  46. Optical transient (GRB?) in Lynx
  47. GRB041211: RAPTOR observations
  48. GRB041211: Ashra Prototype optical observation
  49. GRB041211, BVRcIc field calibration
  50. GRB041211,optical observation
  51. GRB 041211: Infrared Observations
  52. GRB 041211: KAIT observations
  53. GRB 041211: Optical follow-up in East Asian region
  54. Triangulation of short GRB 041116 (large error box)
  55. GRB 040924: Afterglow Color
  56. GRB 041006: GETS Optical Afterglow Observation
  57. Summary of the recent bursts from SGR 1806-20
  58. GRB 041006: Optical Observations
  59. GRB041006, late-time optical photometry
  60. GRB041006: RTT150 Optical Observations
  61. HST Observations: XRF 040701 and 040812
  62. Bright bursts from SGR1806-20
  63. GRB 041016: BOOTES-2 simultaneous observation
  64. GRB041006: RTT150 Optical Observations
  65. GRB041016,optical observation
  66. GRB 041016: Optical limits
  67. GRB 041016:Optical limit during first minute
  68. GRB 041015: Optical Observations at Rikubetsu
  69. GRB 041016: Optical limit
  70. GRB 041015 R band observations
  71. GRB040924, BVRcIc field calibration
  72. GRB041015,optical observation
  73. GRB041006: Fading X-ray Afterglow Observed with Chandra
  74. GRB 041015 - A long GRB detected by INTEGRAL
  75. GRB041006: VLT observations of the afterglow and host galaxy
  76. GRB041006: Optical observations and Potential host galaxy
  77. GRB041006, BVRcIc field calibration
  78. GRB 040924: VLT spectroscopy
  79. GRB 041006: SARA afterglow observations
  80. GRB041006, optical observation in CrAO
  81. Search for SN light in XRF 040912 with MEGACAM
  82. GRB 041006: BR observations with VATT
  83. GRB 041006: Redshift confirmed
  84. GRB 041006: Radio Observations
  85. GRB 041006 : optical follow-up observation at Lulin Observatory
  86. GRB041006: Optical photometry and spectroscopy at TNG
  87. GRB 041006: presice astrometry
  88. GRB041006, optical I observation
  89. GRB041006 (=HETE3570): optical observations
  90. ROTSE-IIIa Observations of GRB 041006
  91. GRB041006: MASTER optical observations
  92. GRB041006,optical observation
  93. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  94. GRB041006: Fading of optical afterglow candidate
  95. GRB 041006: Optical afterglow candidate
  96. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  97. XRF 020903: Observations of the Host Galaxy
  98. radio observations, GRB 040924
  99. GRB040929,optical observation
  100. GRB040924,optical observation

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