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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"

28871 results found.

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

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