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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"

28038 results found.

  1. GRB041223: decay of the afterglow
  2. GRB 041224: near-infrared observations with REM
  3. GRB 041223 Fluence measured by Swift-BAT
  4. GRB041223: optical and NIR observations with REM
  5. Swift-BAT Time History of GRB041219
  6. GRB 041219: TAROT optical observations
  7. GRB 041218: TAROT optical observations
  8. GRB 041223: J-band observations of the afterglow
  9. GRB 041219c: PROMPT Observations
  10. GRB041223: Swift-BAT detection of a bright long burst
  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. GRB041219: Continued NIR Observations
  16. GRB 041219 ,optical observation
  17. GRB 041219: Radio Afterglow Detection
  18. GRB 041218 : Radio Observations
  19. GRB 041218: R-band optical observations
  20. GRB041218: optical observations
  21. GRB041219: Confirmed NIR Afterglow
  22. Swift-BAT detection of the bright long burst GRB041219
  23. GRB 041219: Infrared Afterglow Candidate
  24. GRB041219, BVRcIc field calibration
  25. GRB 041219: Infrared Afterglow Candidate
  26. GRB041218, BVRcIc field calibration
  27. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  28. GRB 041219 - A long GRB detected by INTEGRAL
  29. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  30. GRB 041217: PROMPT Observations
  31. GRB 041217: LCO40 Optical Observations and Possible Candidates
  32. GRB 041218 - A long GRB detected by integral
  33. GRB041217: NIR and optical observations with REM
  34. GRB041217: Infrared Observations
  35. GRB041217: The First GRB Located On-Board Swift
  36. GRB041211: Faulkes Telescope continued optical monitoring
  37. Optical Transient in Lynx not a GRB
  38. Optical transient (GRB?) in Lynx
  39. GRB041211: RAPTOR observations
  40. GRB041211: Ashra Prototype optical observation
  41. GRB041211, BVRcIc field calibration
  42. GRB041211,optical observation
  43. GRB 041211: Infrared Observations
  44. GRB 041211: KAIT observations
  45. GRB 041211: Optical follow-up in East Asian region
  46. Triangulation of short GRB 041116 (large error box)
  47. GRB 040924: Afterglow Color
  48. GRB 041006: GETS Optical Afterglow Observation
  49. Summary of the recent bursts from SGR 1806-20
  50. GRB 041006: Optical Observations
  51. GRB041006, late-time optical photometry
  52. GRB041006: RTT150 Optical Observations
  53. HST Observations: XRF 040701 and 040812
  54. Bright bursts from SGR1806-20
  55. GRB 041016: BOOTES-2 simultaneous observation
  56. GRB041006: RTT150 Optical Observations
  57. GRB041016,optical observation
  58. GRB 041016: Optical limits
  59. GRB 041016:Optical limit during first minute
  60. GRB 041015: Optical Observations at Rikubetsu
  61. GRB 041016: Optical limit
  62. GRB 041015 R band observations
  63. GRB040924, BVRcIc field calibration
  64. GRB041015,optical observation
  65. GRB041006: Fading X-ray Afterglow Observed with Chandra
  66. GRB 041015 - A long GRB detected by INTEGRAL
  67. GRB041006: VLT observations of the afterglow and host galaxy
  68. GRB041006: Optical observations and Potential host galaxy
  69. GRB041006, BVRcIc field calibration
  70. GRB 040924: VLT spectroscopy
  71. GRB 041006: SARA afterglow observations
  72. GRB041006, optical observation in CrAO
  73. Search for SN light in XRF 040912 with MEGACAM
  74. GRB 041006: BR observations with VATT
  75. GRB 041006: Redshift confirmed
  76. GRB 041006: Radio Observations
  77. GRB 041006 : optical follow-up observation at Lulin Observatory
  78. GRB041006: Optical photometry and spectroscopy at TNG
  79. GRB 041006: presice astrometry
  80. GRB041006, optical I observation
  81. GRB041006 (=HETE3570): optical observations
  82. ROTSE-IIIa Observations of GRB 041006
  83. GRB041006: MASTER optical observations
  84. GRB041006,optical observation
  85. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  86. GRB041006: Fading of optical afterglow candidate
  87. GRB 041006: Optical afterglow candidate
  88. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  89. XRF 020903: Observations of the Host Galaxy
  90. radio observations, GRB 040924
  91. GRB040929,optical observation
  92. GRB040924,optical observation
  93. GRB040924,optical observation
  94. GRB 040924: detection of possible host galaxy by Subaru
  95. GRB040924: KAIT observations
  96. GRB040924 : Optical candidate observations at Lulin observatory
  97. GRB040924 : Optical candidate observations at Lulin observatory
  98. GRB 040924: Subaru NIR observation
  99. XRF 040912: Radio Observations
  100. XRF 040916: Radio Observations

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