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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"

25224 results found.

  1. GRB041219: Continued NIR Observations
  2. GRB 041219 ,optical observation
  3. GRB 041219: Radio Afterglow Detection
  4. GRB 041218 : Radio Observations
  5. GRB 041218: R-band optical observations
  6. GRB041218: optical observations
  7. GRB041219: Confirmed NIR Afterglow
  8. Swift-BAT detection of the bright long burst GRB041219
  9. GRB 041219: Infrared Afterglow Candidate
  10. GRB041219, BVRcIc field calibration
  11. GRB 041219: Infrared Afterglow Candidate
  12. GRB041218, BVRcIc field calibration
  13. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  14. GRB 041219 - A long GRB detected by INTEGRAL
  15. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  16. GRB 041217: PROMPT Observations
  17. GRB 041217: LCO40 Optical Observations and Possible Candidates
  18. GRB 041218 - A long GRB detected by integral
  19. GRB041217: NIR and optical observations with REM
  20. GRB041217: Infrared Observations
  21. GRB041217: The First GRB Located On-Board Swift
  22. GRB041211: Faulkes Telescope continued optical monitoring
  23. Optical Transient in Lynx not a GRB
  24. Optical transient (GRB?) in Lynx
  25. GRB041211: RAPTOR observations
  26. GRB041211: Ashra Prototype optical observation
  27. GRB041211, BVRcIc field calibration
  28. GRB041211,optical observation
  29. GRB 041211: Infrared Observations
  30. GRB 041211: KAIT observations
  31. GRB 041211: Optical follow-up in East Asian region
  32. Triangulation of short GRB 041116 (large error box)
  33. GRB 040924: Afterglow Color
  34. GRB 041006: GETS Optical Afterglow Observation
  35. Summary of the recent bursts from SGR 1806-20
  36. GRB 041006: Optical Observations
  37. GRB041006, late-time optical photometry
  38. GRB041006: RTT150 Optical Observations
  39. HST Observations: XRF 040701 and 040812
  40. Bright bursts from SGR1806-20
  41. GRB 041016: BOOTES-2 simultaneous observation
  42. GRB041006: RTT150 Optical Observations
  43. GRB041016,optical observation
  44. GRB 041016: Optical limits
  45. GRB 041016:Optical limit during first minute
  46. GRB 041015: Optical Observations at Rikubetsu
  47. GRB 041016: Optical limit
  48. GRB 041015 R band observations
  49. GRB040924, BVRcIc field calibration
  50. GRB041015,optical observation
  51. GRB041006: Fading X-ray Afterglow Observed with Chandra
  52. GRB 041015 - A long GRB detected by INTEGRAL
  53. GRB041006: VLT observations of the afterglow and host galaxy
  54. GRB041006: Optical observations and Potential host galaxy
  55. GRB041006, BVRcIc field calibration
  56. GRB 040924: VLT spectroscopy
  57. GRB 041006: SARA afterglow observations
  58. GRB041006, optical observation in CrAO
  59. Search for SN light in XRF 040912 with MEGACAM
  60. GRB 041006: BR observations with VATT
  61. GRB 041006: Redshift confirmed
  62. GRB 041006: Radio Observations
  63. GRB 041006 : optical follow-up observation at Lulin Observatory
  64. GRB041006: Optical photometry and spectroscopy at TNG
  65. GRB 041006: presice astrometry
  66. GRB041006, optical I observation
  67. GRB041006 (=HETE3570): optical observations
  68. ROTSE-IIIa Observations of GRB 041006
  69. GRB041006: MASTER optical observations
  70. GRB041006,optical observation
  71. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  72. GRB041006: Fading of optical afterglow candidate
  73. GRB 041006: Optical afterglow candidate
  74. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  75. XRF 020903: Observations of the Host Galaxy
  76. radio observations, GRB 040924
  77. GRB040929,optical observation
  78. GRB040924,optical observation
  79. GRB040924,optical observation
  80. GRB 040924: detection of possible host galaxy by Subaru
  81. GRB040924: KAIT observations
  82. GRB040924 : Optical candidate observations at Lulin observatory
  83. GRB040924 : Optical candidate observations at Lulin observatory
  84. GRB 040924: Subaru NIR observation
  85. XRF 040912: Radio Observations
  86. XRF 040916: Radio Observations
  87. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  88. XRF040916: continuing decay of OT
  89. TAROT Observations of GRB 040916 (HETE #3558)
  90. GRB040912(=H3557): Candidate Optical Afterglow
  91. XRF040916, optical observations
  92. XRF 040912, identification of CXO sources
  93. XRF040912, BVRcIc field calibration
  94. XRF040916, BVRcIc field calibration
  95. GRB040916: Archival optical observations
  96. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  97. GRB040916: Optical observations
  98. GRB040912 (= H3557): Chandra Observations Scheduled
  99. GRB 040912: Optical Observations
  100. GRB/XRF040912,optical observations

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