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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"
  1. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  2. XRF 020903: Observations of the Host Galaxy (authors)
  3. XRF 020903: Observations of the Host Galaxy
  4. SGR 1806-20 still active
  5. GRB 040924: Second Epoch WSRT Radio Observations
  6. radio observations, GRB 040924
  7. IBAS Alert 1991. Not a real GRB
  8. GRB040929,optical observation
  9. GRB040929: MASTER optical observations
  10. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  11. GRB040924,optical observation
  12. GRB040924, RTT150 optical observation
  13. GRB040924,optical observation
  14. GRB 040924: detection of possible host galaxy by Subaru
  15. GRB040924, RTT150 optical observation
  16. GRB040924: KAIT observations
  17. GRB040924: Afterglow magnitude at t=17.5hr
  18. GRB 040924: WSRT Radio Observations
  19. GRB 040924: NIR finding chart
  20. GRB040924 : Optical candidate observations at Lulin observatory
  21. GRB040924 : Optical candidate observations at Lulin observatory
  22. GRB 040924: Subaru NIR observation
  23. GRB040924: Optical afterglow properties
  24. GRB 040924: RTT150 optical observations
  25. GRB 040924, optical follow-up
  26. GRB040924: MASTER: OT decay
  27. GRB040924: MASTER Optical observations
  28. IPN triangulation of GRB040924 (H3564)
  29. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  30. GRB040924 (H3564): Optical afterglow candidate
  31. XRF 040912: Radio Observations
  32. XRF 040916: Radio Observations
  33. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  34. XRF040916: continuing decay of OT
  35. TAROT Observations of GRB 040916 (HETE #3558)
  36. GRB040912(=H3557): Candidate Optical Afterglow
  37. XRF040916, optical observations
  38. XRF040916: Optical Transient Candidate by Subaru
  39. GRB040916 optical limits 17 min after GRB
  40. XRF 040912, identification of CXO sources
  41. XRF 040912 (=H3557): Spectral and Temporal Properties
  42. XRF040916, Ic observations
  43. XRF040916: optical follow-up observations
  44. XRF040912, BVRcIc field calibration
  45. XRF040916, BVRcIc field calibration
  46. GRB040916: Archival optical observations
  47. XRF 040916, optical follow-up
  48. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  49. GRB040916: Optical observations
  50. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  51. GRB040916 (= H3558): Improved Localization from HETE WXM
  52. GRB040916 (= H3558): A Long XRF Localized by HETE
  53. GRB040912 (= H3557): Chandra Observations Scheduled
  54. GRB 040912: Optical Observations
  55. GRB/XRF040912,optical observations
  56. GRB 040912, BVRI observations
  57. Optical observations of GRB/XRF 040912 = HETE 3557
  58. An intense burst from SGR1806-20
  59. GRB040912 : Kiso Optical follow-up observation
  60. IBAS GRB Alerts 1978-1980
  61. Optical observations of field of GRB040912
  62. HETE 3557: Optical observations
  63. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  64. GRB 040827: XMM-Newton data
  65. GRB040903 - A XRF?
  66. GRB040827: analysis of the XMM-Newton observation
  67. GRB040903, REM near-IR observation
  68. GRB 040903 - INTEGRAL data analysis
  69. IBAS Alert 1974. Not a real GRB
  70. Very bright burst detected from SGR 1806-20
  71. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  72. Possible GRB 040903 - further analysis
  73. Possible GRB 040903 detected with INTEGRAL
  74. GRB 040827 - Radio Observations
  75. XMM-Newton Images of GRB 040827
  76. GRB040825A: Optical observations
  77. GRB040825A: Optical observations
  78. GRB 040827: optical and NIR observations at the VLT
  79. GRB 040827: UKIRT - 2nd epoch K-band imaging
  80. GRB 040827: 2nd epoch of Magellan K-band imaging
  81. GRB 040827: K imaging - no evidence of variability
  82. GRB 040827: Detection of NIR afterglow
  83. GRB 040827: Possible detection of optical afterglow
  84. GRB 040827: RTT150 optical observations
  85. GRB040827 XMM-Newton observation
  86. GRB040825A: optical limit before GRB
  87. MASTER: GRB040827 possible OT
  88. GRB 040825B: Optical observations
  89. GRB040827 optical observations
  90. GRB 040827 : Planned XMM-Newton observation
  91. GRB 040827 - Refined position
  92. GRB 040827 : peak flux
  93. GRB 040827 - A long GRB detected by INTEGRAL
  94. GRB040825B, BVRcIc field photometry
  95. GRB040825A, BVRcIc field photometry
  96. GCN GRB OBSERBATION REPORT
  97. GRB 040825A,optical observations
  98. Increase of SGR 1806-20 activity
  99. GRB040825A: optical observations
  100. GRB040825B: optical observations

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