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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"

26173 results found.

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

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