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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"

27415 results found.

  1. GRB 041016: Optical limits
  2. GRB 041016:Optical limit during first minute
  3. GRB041016: MASTER: Optical observations
  4. GRB041006: Near Infrared observations
  5. GRB 041016: Optical limit
  6. GRB 041015 R band observations
  7. GRB040924, BVRcIc field calibration
  8. GRB041015: MASTER: Optical observations
  9. GRB041015,optical observation
  10. GRB041006: MASTER optical observations
  11. GRB041006,optical observation
  12. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  13. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  14. GRB040929,optical observation
  15. GRB040924,optical observation
  16. GRB040924: KAIT observations
  17. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  18. GRB040924 (H3564): Optical afterglow candidate
  19. XRF040912, BVRcIc field calibration
  20. XRF040916, BVRcIc field calibration
  21. GRB040916: Optical observations
  22. GRB/XRF040912,optical observations
  23. GRB 040912, BVRI observations
  24. Optical observations of field of GRB040912
  25. HETE 3557: Optical observations
  26. GRB040825B, BVRcIc field photometry
  27. GRB040825A, BVRcIc field photometry
  28. GCN GRB OBSERBATION REPORT
  29. GRB 040825A,optical observations
  30. Increase of SGR 1806-20 activity
  31. GRB040825A: optical observations
  32. GRB040825B: optical observations
  33. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  34. GRB 040825A: Optical observations.
  35. MASTER: GRB040825b optical observation
  36. GRB040825B: Correction to GCN 2657
  37. GRB 040812: Second epoch CXO Observations
  38. GRB040823,optical observation
  39. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  40. CXO observation of GRB 040812
  41. Ongoing activity of SGR 1806-20
  42. GRB040709 J,H-band observations
  43. GRB040706:observation at University of Miyazaki
  44. GRB 040606: Optical observations
  45. MASTER: HETE Alert 3274 optical observation
  46. Activivty of SGR 1806-20
  47. GRB 040511: Optical limit
  48. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  49. GRB040511: Optical Observations
  50. GRB040511: Optical Observations
  51. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  52. GRB040422: optical observations at CrAO
  53. GRB 040423 (=H3175): A Long GRB Localized by HETE
  54. GRB040422, optical observations at Loiano
  55. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  56. GRB 040422,optical observation
  57. MASTER: HETE Alert 3163, 3167 technical optical observation
  58. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  59. IBAS GRB Alert 1694
  60. GRB 040228 Optical observations
  61. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  62. Follow-up on IBAS GRB Alert 1379
  63. IBAS GRB alert 1379
  64. GRB 031220: Optical observations of Chandra X-ray sources
  65. GRB040106: optical observations with REM+ROSS
  66. GRB031220: observation at Univercity of Miyazaki
  67. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  68. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  69. GRB 031220: Optical observation at Tokyo Tech
  70. GRB031220: ROTSE-IIIb Optical Limits
  71. IPN/HETE localization of GRB031203B (=H2949; large error box)
  72. IPN/HETE localization of GRB031109 (=H2917; large error box)
  73. GRB 031111, Radio observations
  74. HETE Prompt GRB Spectral Analyses
  75. GRB 031026: Ic Observations
  76. HETE Prompt GRB Light Curves and Color-Color Diagrams
  77. XRF 030723: Detection of the likely host galaxy
  78. GRB030922 triangulation (annulus)
  79. GRB 030913: Optical limit at RIKEN
  80. XRF030824: optical observations
  81. GRB030823: optical observations
  82. GRB030823: optical observation at Tokyo Tech
  83. GRB 030817 = H2808 TAROT optical observations
  84. SGR 1808-20 (=H2802): A Possible new SGR
  85. XRF030723, ROTSE-III Early Observations
  86. XRF030723, optical observations
  87. GRBlog: Compilation of all GCN Circ. data
  88. HETE detection of burst from SGR1806-20
  89. MASTER: optical observation GRB030601
  90. GRB 030528: Optical observations at RIKEN
  91. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  92. GRB030429: RTT150 optical observations, a possible host galaxy
  93. GRB 030429: Radio Observations
  94. GRB 030429: redshift from VLT spectroscopy
  95. GRB030429: Optical Observations
  96. GRB 030501: TAROT possible candidate counterpart
  97. GRB 030429: confirmation of afterglow candidate
  98. GRB030429, possible optical counterpart
  99. GRB 030429: ROTSE-III observations
  100. GRB 030418: Optical afterglow candidate

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