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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"

26785 results found.

  1. GRB040825A: optical observations
  2. GRB040825B: optical observations
  3. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  4. GRB 040825A: Optical observations.
  5. MASTER: GRB040825b optical observation
  6. GRB040825B: Correction to GCN 2657
  7. GRB 040812: Second epoch CXO Observations
  8. GRB040823,optical observation
  9. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  10. CXO observation of GRB 040812
  11. Ongoing activity of SGR 1806-20
  12. GRB040709 J,H-band observations
  13. GRB040706:observation at University of Miyazaki
  14. GRB 040606: Optical observations
  15. MASTER: HETE Alert 3274 optical observation
  16. Activivty of SGR 1806-20
  17. GRB 040511: Optical limit
  18. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  19. GRB040511: Optical Observations
  20. GRB040511: Optical Observations
  21. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  22. GRB040422: optical observations at CrAO
  23. GRB 040423 (=H3175): A Long GRB Localized by HETE
  24. GRB040422, optical observations at Loiano
  25. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  26. GRB 040422,optical observation
  27. MASTER: HETE Alert 3163, 3167 technical optical observation
  28. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  29. IBAS GRB Alert 1694
  30. GRB 040228 Optical observations
  31. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  32. Follow-up on IBAS GRB Alert 1379
  33. IBAS GRB alert 1379
  34. GRB 031220: Optical observations of Chandra X-ray sources
  35. GRB040106: optical observations with REM+ROSS
  36. GRB031220: observation at Univercity of Miyazaki
  37. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  38. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  39. GRB 031220: Optical observation at Tokyo Tech
  40. GRB031220: ROTSE-IIIb Optical Limits
  41. IPN/HETE localization of GRB031203B (=H2949; large error box)
  42. IPN/HETE localization of GRB031109 (=H2917; large error box)
  43. GRB 031111, Radio observations
  44. HETE Prompt GRB Spectral Analyses
  45. GRB 031026: Ic Observations
  46. HETE Prompt GRB Light Curves and Color-Color Diagrams
  47. XRF 030723: Detection of the likely host galaxy
  48. GRB030922 triangulation (annulus)
  49. GRB 030913: Optical limit at RIKEN
  50. XRF030824: optical observations
  51. GRB030823: optical observations
  52. GRB030823: optical observation at Tokyo Tech
  53. GRB 030817 = H2808 TAROT optical observations
  54. SGR 1808-20 (=H2802): A Possible new SGR
  55. XRF030723, ROTSE-III Early Observations
  56. XRF030723, optical observations
  57. GRBlog: Compilation of all GCN Circ. data
  58. HETE detection of burst from SGR1806-20
  59. MASTER: optical observation GRB030601
  60. GRB 030528: Optical observations at RIKEN
  61. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  62. GRB030429: RTT150 optical observations, a possible host galaxy
  63. GRB 030429: Radio Observations
  64. GRB 030429: redshift from VLT spectroscopy
  65. GRB030429: Optical Observations
  66. GRB 030501: TAROT possible candidate counterpart
  67. GRB 030429: confirmation of afterglow candidate
  68. GRB030429, possible optical counterpart
  69. GRB 030429: ROTSE-III observations
  70. GRB 030418: Optical afterglow candidate
  71. GRB030329: Near Infrared Observations at Gunma
  72. GRB030329: optical observations at Tokyo Tech
  73. Photometry of GRB030329 - Constant OT Magnitude
  74. GRB030329 - OT brightens
  75. GRB 030329: OT observations at Kanazawa
  76. 030331 NOT A GRB
  77. GRB030329 - Light curve flattening
  78. GRB030329 - near contemporaneous optical limits from CONCAM
  79. GRB 030329, optical observations
  80. GRB 030329: Upper limit from 5.6 hours before trigger
  81. GRB 030329: optical observations
  82. GRB 030329, R-band observations
  83. RXTE detection of GRB 030329 afterglow
  84. GRB 030329: Optical Afterglow Observations
  85. GRB 030328: Optical observations
  86. GRB 030328: optical observations
  87. GRB 030329: OT candidate
  88. VLT spectra of GRB 030328
  89. GRB030324 optical observation
  90. GRB030324, optical observations
  91. GRB030324, optical observations
  92. GRB 030324: TAROT optical observations
  93. GRB 030324 (HETE #2641): Optical observations
  94. GRB030324, Optical Observations
  95. VLT/FORS2 spectra of GRB 030323
  96. GRB030323, ROTSE-III detection of possible optical counterpart
  97. GRB030323, optical observations
  98. GRB030324, BVRcIc field photometry
  99. GRB030323, possible optical counterpart
  100. GRB030323, BVRcIc field calibration

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