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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"

36028 results found.

  1. GRB041223: optical and NIR observations with REM
  2. GRB 041219: TAROT optical observations
  3. GRB 041218: TAROT optical observations
  4. GRB 041223: J-band observations of the afterglow
  5. GRB 041223: Detection of Optical Transient with LCO40
  6. GRB 041219c: PROMPT Observations
  7. GRB 041218: optical observations
  8. GRB 041219: Second Epoch WSRT Radio Observations
  9. GRB 041219: WSRT Radio Afterglow Detection
  10. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  11. GRB 041218: Optical observations
  12. GRB 041219 : optical follow-up observations
  13. Deep RAPTOR observations during GRB 041219
  14. GRB 041218 Optical Observations
  15. GRB 041219 Optical Observations
  16. GRB041219c: Third Burst in One Day from Swift-BAT
  17. GRB041219: Optical Afterglow Detection
  18. GRB041219: Continued NIR Observations
  19. GRB 041219 ,optical observation
  20. GRB 041219: Radio Afterglow Detection
  21. GRB 041218 : Radio Observations
  22. GRB 041218: R-band optical observations
  23. GRB041219: Confirmed NIR Afterglow
  24. GRB041218: Continued P60 Optical Observations
  25. GRB 041218: Optical Observation
  26. GRB 041219: Infrared Afterglow Candidate
  27. GRB041219, BVRcIc field calibration
  28. GRB 041219: Infrared Afterglow Candidate
  29. GRB041218, BVRcIc field calibration
  30. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  31. GRB041219: P60 Optical Observations
  32. GRB 041219 - A long GRB detected by INTEGRAL
  33. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  34. GRB 041217: PROMPT Observations
  35. GRB041218: optical observations
  36. GRB041217: optical limit 30 min after GRB
  37. GRB 041218; optical candidate
  38. GRB 041218: Optical observations
  39. GRB 041217: LCO40 Optical Observations and Possible Candidates
  40. GRB 041218 - A long GRB detected by integral
  41. GRB041217: Optical Observations
  42. GRB041217: P60 Optical Observations
  43. GRB041217: Infrared Observations
  44. GRB041217: The First GRB Located On-Board Swift
  45. GRB041211: Faulkes Telescope continued optical monitoring
  46. Optical Transient in Lynx not a GRB
  47. Optical transient (GRB?) in Lynx
  48. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  49. GRB041211: Continued P60 Observations
  50. GRB041211: RAPTOR observations
  51. GRB041211: Ashra Prototype optical observation
  52. GRB041211, Faulkes Telescope optical observation
  53. GRB041211, BVRcIc field calibration
  54. GRB 041211: Infrared Observations
  55. GRB 041211: KAIT observations
  56. GRB 041211: Optical follow-up in East Asian region
  57. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  58. GRB041211: P60 optical imaging
  59. GRB970815: Discovery of Optical Afterglow
  60. Distribution of IBAS Alerts for NON-GRB sources
  61. Triangulation of short GRB 041116 (large error box)
  62. GRB 040924: Afterglow Color
  63. GRB 041006: GETS Optical Afterglow Observation
  64. Summary of the recent bursts from SGR 1806-20
  65. GRB 041006: Optical Observations
  66. GRB041006, late-time optical photometry
  67. IBAS GRB Alert # 2034
  68. GRB041006: RTT150 Optical Observations
  69. Bright bursts from SGR1806-20
  70. GRB 041016: BOOTES-2 simultaneous observation
  71. GRB041006: RTT150 Optical Observations
  72. GRB 041016: Optical limits
  73. GRB 041016: Optical limits in V, R, I
  74. GRB 041016:Optical limit during first minute
  75. GRB041016: MASTER: Optical observations
  76. GRB 041015: Optical Observations at Rikubetsu
  77. GRB041006: Near Infrared observations
  78. GRB 041016: Optical limit
  79. GRB 041015 R band observations
  80. GRB040924, BVRcIc field calibration
  81. GRB041015: MASTER: Optical observations
  82. GRB041015,optical observation
  83. GRB 041015: Optical limit at Osaka University
  84. GRB041015 : Optical follow-up at Kiso
  85. GRB 041015 - A long GRB detected by INTEGRAL
  86. GRB 041006 R observations in Loiano
  87. GRB041006: VLT observations of the afterglow and host galaxy
  88. GRB041006: Optical observations and Potential host galaxy
  89. GRB041006, BVRcIc field calibration
  90. GRB 040924: VLT spectroscopy
  91. GRB 041006: SARA afterglow observations
  92. Search for SN light in XRF 040912 with MEGACAM
  93. GRB 040916: Afterglow Color at Early Times
  94. GRB 041006 Optical afterglow observations
  95. IBAS GRB Alert # 2010
  96. GRB 041006: BR observations with VATT
  97. GRB 041006: Redshift confirmed
  98. GRB041006: Liverpool Telescope optical observations
  99. GRB 041006: Colour measurement
  100. GRB041006: break in the light curve

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