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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"

28072 results found.

  1. GRB 040606: Optical observations
  2. MASTER: HETE Alert 3274 optical observation
  3. Activivty of SGR 1806-20
  4. GRB 040511: Optical limit
  5. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  6. GRB040511: Optical Observations
  7. GRB040511: Optical Observations
  8. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  9. GRB040422: optical observations at CrAO
  10. GRB 040423 (=H3175): A Long GRB Localized by HETE
  11. GRB040422, optical observations at Loiano
  12. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  13. GRB 040422,optical observation
  14. MASTER: HETE Alert 3163, 3167 technical optical observation
  15. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  16. IBAS GRB Alert 1694
  17. GRB 040228 Optical observations
  18. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  19. Follow-up on IBAS GRB Alert 1379
  20. IBAS GRB alert 1379
  21. GRB 031220: Optical observations of Chandra X-ray sources
  22. GRB040106: optical observations with REM+ROSS
  23. GRB031220: observation at Univercity of Miyazaki
  24. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  25. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  26. GRB 031220: Optical observation at Tokyo Tech
  27. GRB031220: ROTSE-IIIb Optical Limits
  28. IPN/HETE localization of GRB031203B (=H2949; large error box)
  29. IPN/HETE localization of GRB031109 (=H2917; large error box)
  30. GRB 031111, Radio observations
  31. HETE Prompt GRB Spectral Analyses
  32. GRB 031026: Ic Observations
  33. HETE Prompt GRB Light Curves and Color-Color Diagrams
  34. XRF 030723: Detection of the likely host galaxy
  35. GRB030922 triangulation (annulus)
  36. GRB 030913: Optical limit at RIKEN
  37. XRF030824: optical observations
  38. GRB030823: optical observations
  39. GRB030823: optical observation at Tokyo Tech
  40. GRB 030817 = H2808 TAROT optical observations
  41. SGR 1808-20 (=H2802): A Possible new SGR
  42. XRF030723, ROTSE-III Early Observations
  43. XRF030723, optical observations
  44. GRBlog: Compilation of all GCN Circ. data
  45. HETE detection of burst from SGR1806-20
  46. MASTER: optical observation GRB030601
  47. GRB 030528: Optical observations at RIKEN
  48. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  49. GRB030429: RTT150 optical observations, a possible host galaxy
  50. GRB 030429: Radio Observations
  51. GRB 030429: redshift from VLT spectroscopy
  52. GRB030429: Optical Observations
  53. GRB 030501: TAROT possible candidate counterpart
  54. GRB 030429: confirmation of afterglow candidate
  55. GRB030429, possible optical counterpart
  56. GRB 030429: ROTSE-III observations
  57. GRB 030418: Optical afterglow candidate
  58. GRB030329: Near Infrared Observations at Gunma
  59. GRB030329: optical observations at Tokyo Tech
  60. Photometry of GRB030329 - Constant OT Magnitude
  61. GRB030329 - OT brightens
  62. GRB 030329: OT observations at Kanazawa
  63. 030331 NOT A GRB
  64. GRB030329 - Light curve flattening
  65. GRB030329 - near contemporaneous optical limits from CONCAM
  66. GRB 030329, optical observations
  67. GRB 030329: Upper limit from 5.6 hours before trigger
  68. GRB 030329: optical observations
  69. GRB 030329, R-band observations
  70. RXTE detection of GRB 030329 afterglow
  71. GRB 030329: Optical Afterglow Observations
  72. GRB 030328: Optical observations
  73. GRB 030328: optical observations
  74. GRB 030329: OT candidate
  75. VLT spectra of GRB 030328
  76. GRB030324 optical observation
  77. GRB030324, optical observations
  78. GRB030324, optical observations
  79. GRB 030324: TAROT optical observations
  80. GRB 030324 (HETE #2641): Optical observations
  81. GRB030324, Optical Observations
  82. VLT/FORS2 spectra of GRB 030323
  83. GRB030323, ROTSE-III detection of possible optical counterpart
  84. GRB030323, optical observations
  85. GRB030324, BVRcIc field photometry
  86. GRB030323, possible optical counterpart
  87. GRB030323, BVRcIc field calibration
  88. GRB 030324 optical observations
  89. GRB 030324, optical observations
  90. GRB 030227: Optical limit at RIKEN
  91. Chandra detection of the X-ray afterglow of GRB 030226
  92. 030302: NOT A GRB
  93. 030228: NOT A GRB
  94. GRB 030228, optical observations
  95. GRB 030226: R band polarimetric observations
  96. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  97. GRB 030226 simultaneous optical observations
  98. GRB030226: Candidate optical afterglow
  99. IPN triangulation of GRB030215C (annulus)
  100. GRB 030115, simultaneous observations by BOOTES-1

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