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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"

23417 results found.

  1. GRB041217: The First GRB Located On-Board Swift
  2. GRB041211: Faulkes Telescope continued optical monitoring
  3. Optical transient (GRB?) in Lynx
  4. GRB041211: RAPTOR observations
  5. GRB041211: Ashra Prototype optical observation
  6. GRB041211, BVRcIc field calibration
  7. GRB041211,optical observation
  8. GRB 041211: Infrared Observations
  9. GRB 041211: KAIT observations
  10. GRB 041211: Optical follow-up in East Asian region
  11. Triangulation of short GRB 041116 (large error box)
  12. GRB 040924: Afterglow Color
  13. GRB 041006: GETS Optical Afterglow Observation
  14. Summary of the recent bursts from SGR 1806-20
  15. GRB 041006: Optical Observations
  16. GRB041006, late-time optical photometry
  17. GRB041006: RTT150 Optical Observations
  18. HST Observations: XRF 040701 and 040812
  19. GRB 041016: BOOTES-2 simultaneous observation
  20. GRB041006: RTT150 Optical Observations
  21. GRB041016,optical observation
  22. GRB 041016: Optical limits
  23. GRB 041016:Optical limit during first minute
  24. GRB 041016: Optical limit
  25. GRB 041015 R band observations
  26. GRB040924, BVRcIc field calibration
  27. GRB041015,optical observation
  28. GRB041006: Fading X-ray Afterglow Observed with Chandra
  29. GRB 041015 - A long GRB detected by INTEGRAL
  30. GRB041006: Optical observations and Potential host galaxy
  31. GRB041006, BVRcIc field calibration
  32. GRB 041006: SARA afterglow observations
  33. GRB041006, optical observation in CrAO
  34. Search for SN light in XRF 040912 with MEGACAM
  35. GRB 040916: Afterglow Color at Early Times
  36. GRB 041006: BR observations with VATT
  37. GRB 041006 : Optical follow-up observation at TAROT
  38. GRB041006, optical I observation
  39. GRB041006 (=HETE3570): optical observations
  40. ROTSE-IIIa Observations of GRB 041006
  41. GRB041006: MASTER optical observations
  42. GRB041006,optical observation
  43. GRB041006: Fading of optical afterglow candidate
  44. GRB 041006: Optical afterglow candidate
  45. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  46. XRF 020903: Observations of the Host Galaxy
  47. radio observations, GRB 040924
  48. GRB040929,optical observation
  49. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  50. GRB040924,optical observation
  51. GRB040924,optical observation
  52. GRB040924: KAIT observations
  53. GRB 040924: WSRT Radio Observations
  54. GRB 040924: Subaru NIR observation
  55. GRB 040924, optical follow-up
  56. IPN triangulation of GRB040924 (H3564)
  57. XRF 040912: Radio Observations
  58. XRF 040916: Radio Observations
  59. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  60. XRF040916: continuing decay of OT
  61. TAROT Observations of GRB 040916 (HETE #3558)
  62. GRB040912(=H3557): Candidate Optical Afterglow
  63. XRF040916, optical observations
  64. XRF 040912, identification of CXO sources
  65. XRF040916, Ic observations
  66. XRF040912, BVRcIc field calibration
  67. XRF040916, BVRcIc field calibration
  68. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  69. GRB040916: Optical observations
  70. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  71. GRB 040912: Optical Observations
  72. GRB/XRF040912,optical observations
  73. GRB 040912, BVRI observations
  74. Optical observations of GRB/XRF 040912 = HETE 3557
  75. An intense burst from SGR1806-20
  76. GRB040912 : Kiso Optical follow-up observation
  77. Optical observations of field of GRB040912
  78. HETE 3557: Optical observations
  79. GRB040903 - A XRF?
  80. GRB040827: analysis of the XMM-Newton observation
  81. GRB040903, REM near-IR observation
  82. GRB 040903 - INTEGRAL data analysis
  83. Very bright burst detected from SGR 1806-20
  84. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  85. Possible GRB 040903 - further analysis
  86. GRB 040827 - Radio Observations
  87. XMM-Newton Images of GRB 040827
  88. GRB 040827: optical and NIR observations at the VLT
  89. GRB040827 XMM-Newton observation
  90. GRB 040825B: Optical observations
  91. GRB 040827 : Planned XMM-Newton observation
  92. GRB 040827 - A long GRB detected by INTEGRAL
  93. GRB040825B, BVRcIc field photometry
  94. GRB040825A, BVRcIc field photometry
  95. GCN GRB OBSERBATION REPORT
  96. GRB 040825A,optical observations
  97. Increase of SGR 1806-20 activity
  98. GRB040825A: optical observations
  99. GRB040825B: optical observations
  100. GRB 040825A: Optical observations.

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