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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"

26507 results found.

  1. GRB041226: Swift-BAT detection of a burst
  2. GRB041223: decay of the afterglow
  3. GRB 041224: near-infrared observations with REM
  4. GRB 041223 Fluence measured by Swift-BAT
  5. GRB041223: optical and NIR observations with REM
  6. GRB 041219: TAROT optical observations
  7. GRB 041218: TAROT optical observations
  8. GRB 041223: J-band observations of the afterglow
  9. GRB041223: Swift XRT Detection of X-ray Afterglow Emission
  10. GRB 041219c: PROMPT Observations
  11. GRB041223: Swift-BAT detection of a bright long burst
  12. GRB 041218: optical observations
  13. GRB 041219 : optical follow-up observations
  14. GRB041220: Swift-BAT burst
  15. GRB 041218 Optical Observations
  16. GRB041219c: Third Burst in One Day from Swift-BAT
  17. GRB041219: Continued NIR Observations
  18. GRB041219b: A Swift-BAT burst
  19. GRB 041219 ,optical observation
  20. GRB 041219: Radio Afterglow Detection
  21. GRB 041218 : Radio Observations
  22. GRB 041218: R-band optical observations
  23. GRB041218: optical observations
  24. GRB041219: Confirmed NIR Afterglow
  25. GRB041218: Continued P60 Optical Observations
  26. Swift-BAT detection of the bright long burst GRB041219
  27. GRB 041219: Infrared Afterglow Candidate
  28. GRB041219, BVRcIc field calibration
  29. GRB 041219: Infrared Afterglow Candidate
  30. GRB041218, BVRcIc field calibration
  31. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  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. GRB041217: optical limit 30 min after GRB
  36. GRB 041217: LCO40 Optical Observations and Possible Candidates
  37. GRB041217: NIR and optical observations with REM
  38. GRB041217: Infrared Observations
  39. GRB041217: The First GRB Located On-Board Swift
  40. GRB041211: Faulkes Telescope continued optical monitoring
  41. Optical transient (GRB?) in Lynx
  42. GRB041211: RAPTOR observations
  43. GRB041211: Ashra Prototype optical observation
  44. GRB041211, Faulkes Telescope optical observation
  45. GRB041211, BVRcIc field calibration
  46. GRB041211,optical observation
  47. GRB 041211: Infrared Observations
  48. GRB 041211: KAIT observations
  49. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  50. GRB970815: Discovery of Optical Afterglow
  51. Triangulation of short GRB 041116 (large error box)
  52. GRB 040924: Afterglow Color
  53. GRB 041006: GETS Optical Afterglow Observation
  54. GRB 041006: Optical Observations
  55. GRB041006, late-time optical photometry
  56. GRB041006: RTT150 Optical Observations
  57. Bright bursts from SGR1806-20
  58. GRB 041016: BOOTES-2 simultaneous observation
  59. GRB041006: RTT150 Optical Observations
  60. GRB041016,optical observation
  61. GRB 041016: Optical limits
  62. GRB 041016:Optical limit during first minute
  63. GRB 041016: Optical limit
  64. GRB 041015 R band observations
  65. GRB040924, BVRcIc field calibration
  66. GRB041015,optical observation
  67. GRB041006: Fading X-ray Afterglow Observed with Chandra
  68. GRB 041006 R observations in Loiano
  69. GRB041006: Optical observations and Potential host galaxy
  70. GRB041006, BVRcIc field calibration
  71. GRB 041006: SARA afterglow observations
  72. GRB041006, optical observation in CrAO
  73. Search for SN light in XRF 040912 with MEGACAM
  74. GRB 040916: Afterglow Color at Early Times
  75. GRB 041006: BR observations with VATT
  76. GRB 041006: Radio Observations
  77. GRB041006: Optical photometry and spectroscopy at TNG
  78. GRB 041006: presice astrometry
  79. GRB041006, optical I observation
  80. GRB041006 (=HETE3570): optical observations
  81. ROTSE-IIIa Observations of GRB 041006
  82. GRB041006: MASTER optical observations
  83. GRB041006,optical observation
  84. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  85. GRB041006: Fading of optical afterglow candidate
  86. GRB 041006: Optical afterglow candidate
  87. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  88. SGR 1806-20 still active
  89. radio observations, GRB 040924
  90. GRB040929,optical observation
  91. GRB040924,optical observation
  92. GRB040924, RTT150 optical observation
  93. GRB040924,optical observation
  94. GRB040924: KAIT observations
  95. GRB 040924: Subaru NIR observation
  96. GRB 040924, optical follow-up
  97. GRB040924 (H3564): Optical afterglow candidate
  98. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  99. XRF040916: continuing decay of OT
  100. TAROT Observations of GRB 040916 (HETE #3558)

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