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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. GRB041006, optical I observation
  2. GRB041006 (=HETE3570): optical observations
  3. ROTSE-IIIa Observations of GRB 041006
  4. GRB041006, optical observation
  5. GRB041006, submillimetre observations
  6. GRB041006: MASTER optical observations
  7. GRB041006,optical observation
  8. GRB 041006: Optical decay
  9. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  10. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  11. GRB041006: Fading of optical afterglow candidate
  12. GRB 041006 : Optical follow-up observation at KISO
  13. GRB 041006: Finding chart
  14. GRB 041006: Optical afterglow candidate
  15. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  16. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  17. XRF 020903: Observations of the Host Galaxy (authors)
  18. XRF 020903: Observations of the Host Galaxy
  19. SGR 1806-20 still active
  20. GRB 040924: Second Epoch WSRT Radio Observations
  21. radio observations, GRB 040924
  22. IBAS Alert 1991. Not a real GRB
  23. GRB040929,optical observation
  24. GRB040929: MASTER optical observations
  25. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  26. GRB040924,optical observation
  27. GRB040924, RTT150 optical observation
  28. GRB040924,optical observation
  29. GRB 040924: detection of possible host galaxy by Subaru
  30. GRB040924, RTT150 optical observation
  31. GRB040924: KAIT observations
  32. GRB040924: Afterglow magnitude at t=17.5hr
  33. GRB 040924: WSRT Radio Observations
  34. GRB 040924: NIR finding chart
  35. GRB040924 : Optical candidate observations at Lulin observatory
  36. GRB040924 : Optical candidate observations at Lulin observatory
  37. GRB 040924: Subaru NIR observation
  38. GRB040924: Optical afterglow properties
  39. GRB 040924: RTT150 optical observations
  40. GRB 040924, optical follow-up
  41. GRB040924: MASTER: OT decay
  42. GRB040924: MASTER Optical observations
  43. IPN triangulation of GRB040924 (H3564)
  44. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  45. GRB040924 (H3564): Optical afterglow candidate
  46. XRF 040912: Radio Observations
  47. XRF 040916: Radio Observations
  48. GRB040912(=H3557): Chandra Candidate X-ray Afterglow
  49. XRF040916: continuing decay of OT
  50. TAROT Observations of GRB 040916 (HETE #3558)
  51. GRB040912(=H3557): Candidate Optical Afterglow
  52. XRF040916, optical observations
  53. XRF040916: Optical Transient Candidate by Subaru
  54. GRB040916 optical limits 17 min after GRB
  55. XRF 040912, identification of CXO sources
  56. XRF 040912 (=H3557): Spectral and Temporal Properties
  57. XRF040916, Ic observations
  58. XRF040916: optical follow-up observations
  59. XRF040912, BVRcIc field calibration
  60. XRF040916, BVRcIc field calibration
  61. GRB040916: Archival optical observations
  62. XRF 040916, optical follow-up
  63. GRB040912(=H3557): Observations with the Chandra X-ray Observatory
  64. GRB040916: Optical observations
  65. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  66. GRB040916 (= H3558): Improved Localization from HETE WXM
  67. GRB040916 (= H3558): A Long XRF Localized by HETE
  68. GRB040912 (= H3557): Chandra Observations Scheduled
  69. GRB 040912: Optical Observations
  70. GRB/XRF040912,optical observations
  71. GRB 040912, BVRI observations
  72. Optical observations of GRB/XRF 040912 = HETE 3557
  73. An intense burst from SGR1806-20
  74. GRB040912 : Kiso Optical follow-up observation
  75. IBAS GRB Alerts 1978-1980
  76. Optical observations of field of GRB040912
  77. HETE 3557: Optical observations
  78. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  79. GRB 040827: XMM-Newton data
  80. GRB040903 - A XRF?
  81. GRB040827: analysis of the XMM-Newton observation
  82. GRB040903, REM near-IR observation
  83. GRB 040903 - INTEGRAL data analysis
  84. IBAS Alert 1974. Not a real GRB
  85. Very bright burst detected from SGR 1806-20
  86. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  87. Possible GRB 040903 - further analysis
  88. Possible GRB 040903 detected with INTEGRAL
  89. GRB 040827 - Radio Observations
  90. XMM-Newton Images of GRB 040827
  91. GRB040825A: Optical observations
  92. GRB040825A: Optical observations
  93. GRB 040827: optical and NIR observations at the VLT
  94. GRB 040827: UKIRT - 2nd epoch K-band imaging
  95. GRB 040827: 2nd epoch of Magellan K-band imaging
  96. GRB 040827: K imaging - no evidence of variability
  97. GRB 040827: Detection of NIR afterglow
  98. GRB 040827: Possible detection of optical afterglow
  99. GRB 040827: RTT150 optical observations
  100. GRB040827 XMM-Newton observation

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