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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"

27408 results found.

  1. GRB041015: MASTER: Optical observations
  2. GRB041015,optical observation
  3. GRB041006: MASTER optical observations
  4. GRB041006,optical observation
  5. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  6. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  7. GRB040929,optical observation
  8. GRB040924,optical observation
  9. GRB040924: KAIT observations
  10. GRB 040924(=H3564): A Short, Bright GRB Localized in Real Time by HETE
  11. GRB040924 (H3564): Optical afterglow candidate
  12. XRF040912, BVRcIc field calibration
  13. XRF040916, BVRcIc field calibration
  14. GRB040916: Optical observations
  15. GRB/XRF040912,optical observations
  16. GRB 040912, BVRI observations
  17. Optical observations of field of GRB040912
  18. HETE 3557: Optical observations
  19. GRB040825B, BVRcIc field photometry
  20. GRB040825A, BVRcIc field photometry
  21. GCN GRB OBSERBATION REPORT
  22. GRB 040825A,optical observations
  23. Increase of SGR 1806-20 activity
  24. GRB040825A: optical observations
  25. GRB040825B: optical observations
  26. GRB040825B (=H3510): An XRF Localized in Real Time by HETE
  27. GRB 040825A: Optical observations.
  28. MASTER: GRB040825b optical observation
  29. GRB040825B: Correction to GCN 2657
  30. GRB 040812: Second epoch CXO Observations
  31. GRB040823,optical observation
  32. Triangulation of GRB 040816 (Konus-Wind - Helicon-Coronas-F)
  33. CXO observation of GRB 040812
  34. Ongoing activity of SGR 1806-20
  35. GRB040709 J,H-band observations
  36. GRB040706:observation at University of Miyazaki
  37. GRB 040606: Optical observations
  38. MASTER: HETE Alert 3274 optical observation
  39. Activivty of SGR 1806-20
  40. GRB 040511: Optical limit
  41. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  42. GRB040511: Optical Observations
  43. GRB040511: Optical Observations
  44. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  45. GRB040422: optical observations at CrAO
  46. GRB 040423 (=H3175): A Long GRB Localized by HETE
  47. GRB040422, optical observations at Loiano
  48. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  49. GRB 040422,optical observation
  50. MASTER: HETE Alert 3163, 3167 technical optical observation
  51. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  52. IBAS GRB Alert 1694
  53. GRB 040228 Optical observations
  54. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  55. Follow-up on IBAS GRB Alert 1379
  56. IBAS GRB alert 1379
  57. GRB 031220: Optical observations of Chandra X-ray sources
  58. GRB040106: optical observations with REM+ROSS
  59. GRB031220: observation at Univercity of Miyazaki
  60. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  61. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  62. GRB 031220: Optical observation at Tokyo Tech
  63. GRB031220: ROTSE-IIIb Optical Limits
  64. IPN/HETE localization of GRB031203B (=H2949; large error box)
  65. IPN/HETE localization of GRB031109 (=H2917; large error box)
  66. GRB 031111, Radio observations
  67. HETE Prompt GRB Spectral Analyses
  68. GRB 031026: Ic Observations
  69. HETE Prompt GRB Light Curves and Color-Color Diagrams
  70. XRF 030723: Detection of the likely host galaxy
  71. GRB030922 triangulation (annulus)
  72. GRB 030913: Optical limit at RIKEN
  73. XRF030824: optical observations
  74. GRB030823: optical observations
  75. GRB030823: optical observation at Tokyo Tech
  76. GRB 030817 = H2808 TAROT optical observations
  77. SGR 1808-20 (=H2802): A Possible new SGR
  78. XRF030723, ROTSE-III Early Observations
  79. XRF030723, optical observations
  80. GRBlog: Compilation of all GCN Circ. data
  81. HETE detection of burst from SGR1806-20
  82. MASTER: optical observation GRB030601
  83. GRB 030528: Optical observations at RIKEN
  84. XRF030416 (=U10897): An X-Ray Flash Localized by the HETE WXM
  85. GRB030429: RTT150 optical observations, a possible host galaxy
  86. GRB 030429: Radio Observations
  87. GRB 030429: redshift from VLT spectroscopy
  88. GRB030429: Optical Observations
  89. GRB 030501: TAROT possible candidate counterpart
  90. GRB 030429: confirmation of afterglow candidate
  91. GRB030429, possible optical counterpart
  92. GRB 030429: ROTSE-III observations
  93. GRB 030418: Optical afterglow candidate
  94. GRB030329: Near Infrared Observations at Gunma
  95. GRB030329: optical observations at Tokyo Tech
  96. Photometry of GRB030329 - Constant OT Magnitude
  97. GRB030329 - OT brightens
  98. GRB 030329: OT observations at Kanazawa
  99. 030331 NOT A GRB
  100. GRB030329 - Light curve flattening

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