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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"

28043 results found.

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

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