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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"

23685 results found.

  1. GRB 041217: PROMPT Observations
  2. GRB 041218 - A long GRB detected by integral
  3. GRB041217: Infrared Observations
  4. GRB041217: The First GRB Located On-Board Swift
  5. GRB041211: Faulkes Telescope continued optical monitoring
  6. GRB041211: Continued P60 Observations
  7. GRB041211: Ashra Prototype optical observation
  8. GRB041211, Faulkes Telescope optical observation
  9. GRB041211,optical observation
  10. GRB 041211: Optical follow-up in East Asian region
  11. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  12. Distribution of IBAS Alerts for NON-GRB sources
  13. GRB 040924: Afterglow Color
  14. Summary of the recent bursts from SGR 1806-20
  15. GRB 041006: Optical Observations
  16. GRB041006, late-time optical photometry
  17. IBAS GRB Alert # 2034
  18. Bright bursts from SGR1806-20
  19. GRB041016: MASTER: Optical observations
  20. GRB041015: MASTER: Optical observations
  21. GRB041006: Fading X-ray Afterglow Observed with Chandra
  22. GRB 041015: Optical limit at Osaka University
  23. GRB 041015 - A long GRB detected by INTEGRAL
  24. GRB 040924: VLT spectroscopy
  25. Search for SN light in XRF 040912 with MEGACAM
  26. GRB 040916: Afterglow Color at Early Times
  27. IBAS GRB Alert # 2010
  28. GRB041006: Liverpool Telescope optical observations
  29. GRB041006: break in the light curve
  30. GRB 041006 : Optical follow-up observation at TAROT
  31. GRB041006: Optical photometry and spectroscopy at TNG
  32. GRB041006, optical I observation
  33. ROTSE-IIIa Observations of GRB 041006
  34. GRB041006: MASTER optical observations
  35. GRB041006,optical observation
  36. GRB 041006: Optical decay
  37. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  38. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  39. GRB 041006: Optical afterglow candidate
  40. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  41. SGR 1806-20 still active
  42. IBAS Alert 1991. Not a real GRB
  43. GRB040929,optical observation
  44. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  45. GRB040924,optical observation
  46. GRB 040924: detection of possible host galaxy by Subaru
  47. GRB040924: KAIT observations
  48. GRB040924: Optical afterglow properties
  49. GRB040924: MASTER: OT decay
  50. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  51. GRB040924 (H3564): Optical afterglow candidate
  52. TAROT Observations of GRB 040916 (HETE #3558)
  53. GRB040912(=H3557): Candidate Optical Afterglow
  54. XRF 040916, optical follow-up
  55. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  56. GRB040916 (= H3558): Improved Localization from HETE WXM
  57. An intense burst from SGR1806-20
  58. IBAS GRB Alerts 1978-1980
  59. HETE 3557: Optical observations
  60. GRB040912 (= H3557): A Long GRB or XRF Localized by HETE
  61. GRB040903 - A XRF?
  62. GRB040827: analysis of the XMM-Newton observation
  63. GRB040903, REM near-IR observation
  64. IBAS Alert 1974. Not a real GRB
  65. ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
  66. Possible GRB 040903 - further analysis
  67. Possible GRB 040903 detected with INTEGRAL
  68. GRB 040827: optical and NIR observations at the VLT
  69. GRB 040827: K imaging - no evidence of variability
  70. GRB 040827 - Refined position
  71. GRB 040827 - A long GRB detected by INTEGRAL
  72. Increase of SGR 1806-20 activity
  73. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  74. MASTER: GRB040825b optical observation
  75. XRF040812: possible afterglow second Chandra observation
  76. GRB 040812: Second epoch CXO Observations
  77. GRB040823,optical observation
  78. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  79. Bursting activity from SGR 1806-20 detected with IBAS
  80. IPN/HETE localizations of GRB040810 (=H3489)
  81. Konus-Wind observation of GRB040810 (=H3489)
  82. GRB 040812: a long GRB detected by INTEGRAL
  83. GRB 040810: Optical observations of a limited region
  84. IPN/HETE triangulation of GRB040802 (=H3485)
  85. GRB 040730: a long GRB detected with INTEGRAL
  86. Ongoing activity of SGR 1806-20
  87. XRF 040701 - optical observations of the decaying Chandra source
  88. XRF040701: Second-Epoch Chandra Observations
  89. Cancellation of IBAS/INTEGRAL GRB alerts
  90. XRF040701: VLA Observations
  91. XRF040701: First-Epoch Chandra Observations
  92. IBAS Alert 1836: NOT a real GRB
  93. GRB040624, optical observations
  94. GRB040706:observation at University of Miyazaki
  95. GRB 040624: optical observations
  96. GRB 040624: optical observations at TNG and VLT
  97. MASTER: GRB 040624 optical observation after 0,48d
  98. GRB 040624: R-band observations
  99. GRB 040624 - A long GRB detected with INTEGRAL
  100. GRB 030329: Rebrightening of hyperluminal ejecta.

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