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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"

25042 results found.

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

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