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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"
  1. GRB 040511: Optical observations
  2. GRB 040511: Optical Observations
  3. GRB040511: Optical Observations
  4. GRB040511: Optical Observations
  5. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  6. IBAS GRB Alert number 1774: NOT a real GRB
  7. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  8. IBAS Alerts 1771 and 1772: NOT a real GRB
  9. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  10. IPN triangulation of GRB040425 (=H3183)
  11. On Line Availability of Archival HETE Fregate Data and Lightcurves
  12. GRB040422: optical observations at Xinglong Observatory
  13. GRB040422: optical observations at CrAO
  14. GRB 040423 (=H3175): A Long GRB Localized by HETE
  15. GRB040422, optical observations at Loiano
  16. GRB040422 : I-band follow-up observation at Lulin Observatory
  17. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  18. GRB040422, BVRcIc field calibration
  19. GRB 040422,optical observation
  20. GRB040422: optical and NIR observations at the VLT
  21. GRB 040422: a long GRB detected with INTEGRAL
  22. GRB 040403, deep optical observations
  23. MASTER: HETE Alert 3163, 3167 technical optical observation
  24. INTEGRAL-SPI/ACS GRB data: timing correction
  25. IBAS GRB alerts 1739, 1740, 1741
  26. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  27. GRB 040403: Optical Observations
  28. GRB 040403 Optical Observations
  29. GRB 040403: Optical observations
  30. GRB 040403: optical observations
  31. GRB 040403: Optical Observations
  32. GRB 040403: a long GRB detected with INTEGRAL
  33. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  34. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  35. IBAS GRB Alert 1694
  36. GRB040323: NIR Observations and Variable Object
  37. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  38. GRB 040323, a dark GRB ?
  39. short hard GRB 040322
  40. GRB 040323: a long GRB detected with INTEGRAL
  41. IBAS GRB alerts 1679, 1680, 1681
  42. GRB040223: Deep NIR NTT data re-analysis
  43. GRB 040223: XMM-Newton results
  44. GRB040223, improved XMM position
  45. IBAS Alert 1678: not a GRB
  46. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  47. GRB 031203, possible supernova
  48. MASTER: RXTE GRB040308 optical observation
  49. IBAS results on a burst from SGR1806-20
  50. INTEGRAL detection of activity from SGR1806-20
  51. RXTE GRB040229 optical observation: no candidate
  52. GRB 040228 Optical observations
  53. IPN triangulation of GRB040228 (H3066, H3067)
  54. GRB040228 : KISO optical follow-up observation
  55. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  56. GRB 040223: Deep NIR NTT observations
  57. GRB 040223 : Optical observation (non-detection)
  58. XMM-Newton Images of GRB 040223
  59. GRB 040223, VLA observations
  60. GRB 040223: REM IJK Observations
  61. GRB 040223 XMM-Newton observation ...
  62. GRB 031203 XMM-Newton observation
  63. GRB 040223 : Planned XMM-Newton observation
  64. GRB 040106 : Planned XMM-Newton observation
  65. GRB 040223: further offline analysis
  66. GRB 040223: a long GRB detected with INTEGRAL
  67. GRB031111, optical observations
  68. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  69. GRB031203: Chandra Observations
  70. GRB040106, follow-up radio observations
  71. GRB040106: refined X-ray transient position
  72. Follow-up on IBAS GRB Alert 1379
  73. IBAS GRB alert 1379
  74. SN 2003dh/GRB030329 late-time optical spectroscopy
  75. GRB040106, Radio Observations
  76. GRB040106, likely optical afterglow
  77. GRB040106: Second Epoch Optical Observations
  78. GRB 031220: Optical observations of Chandra X-ray sources
  79. XMM-Newton Images of GRB 040106
  80. GRB040106: optical observations with REM+ROSS
  81. GRB031220: observation at Univercity of Miyazaki
  82. GRB 040106: Optical observations
  83. XMM-Newton observation of GRB040106
  84. GRB 040106 : Planned XMM-Newton observation
  85. GRB 040106 : peak flux
  86. GRB 040106 : a long GRB detected with INTEGRAL
  87. IPN triangulation of an intermediate burst from SGR1806-20
  88. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  89. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  90. GRB031225a triangulation (annulus)
  91. IPN triangulation of GRB031219 (large error box)
  92. GRB031220: Palomar Observations
  93. GRB 031220 : Kyoto Optical Observation
  94. GRB 031220: Subaru observation
  95. GRB 031220: Optical observation at Tokyo Tech
  96. GRB031220: ROTSE-IIIb Optical Limits
  97. GRB031220 : Optical Observation of Lulin Observatory
  98. GRB 031203 I-band monitoring
  99. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  100. GRB 2974 follow-up observations

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