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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. IBAS GRB Alerts n.1785 to 1791
  2. GRB 040511: ROTSE-III Rapid Optical Upper Limits
  3. GRB 040511: Second Epoch Optical Observations
  4. IBAS GRB Alerts 1781-4
  5. GRB 040511: Optical observations
  6. GRB 040511: Optical Observations
  7. GRB040511: Optical Observations
  8. GRB040511: Optical Observations
  9. GRB040511 (=H3218): A Long GRB Localized by HETE WXM and SXC
  10. IBAS GRB Alert number 1774: NOT a real GRB
  11. Type Ic SN2001em (off-axis GRB jet?), optical spectrum
  12. IBAS Alerts 1771 and 1772: NOT a real GRB
  13. GRB and XRF on April 27, 2004. Detection by Konus-Wind and Helicon (Coronas-F)
  14. IPN triangulation of GRB040425 (=H3183)
  15. On Line Availability of Archival HETE Fregate Data and Lightcurves
  16. GRB040422: optical observations at Xinglong Observatory
  17. GRB040422: optical observations at CrAO
  18. GRB 040423 (=H3175): A Long GRB Localized by HETE
  19. GRB040422, optical observations at Loiano
  20. GRB040422 : I-band follow-up observation at Lulin Observatory
  21. GRB 040422: ROTSE-IIIb Prompt Optical Limits
  22. GRB040422, BVRcIc field calibration
  23. GRB 040422,optical observation
  24. GRB040422: optical and NIR observations at the VLT
  25. GRB 040422: a long GRB detected with INTEGRAL
  26. GRB 040403, deep optical observations
  27. MASTER: HETE Alert 3163, 3167 technical optical observation
  28. INTEGRAL-SPI/ACS GRB data: timing correction
  29. IBAS GRB alerts 1739, 1740, 1741
  30. HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
  31. GRB 040403: Optical Observations
  32. GRB 040403 Optical Observations
  33. GRB 040403: Optical observations
  34. GRB 040403: optical observations
  35. GRB 040403: Optical Observations
  36. GRB 040403: a long GRB detected with INTEGRAL
  37. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  38. GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
  39. IBAS GRB Alert 1694
  40. GRB040323: NIR Observations and Variable Object
  41. GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
  42. GRB 040323, a dark GRB ?
  43. short hard GRB 040322
  44. GRB 040323: a long GRB detected with INTEGRAL
  45. IBAS GRB alerts 1679, 1680, 1681
  46. GRB040223: Deep NIR NTT data re-analysis
  47. GRB 040223: XMM-Newton results
  48. GRB040223, improved XMM position
  49. IBAS Alert 1678: not a GRB
  50. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  51. GRB 031203, possible supernova
  52. MASTER: RXTE GRB040308 optical observation
  53. IBAS results on a burst from SGR1806-20
  54. INTEGRAL detection of activity from SGR1806-20
  55. RXTE GRB040229 optical observation: no candidate
  56. GRB 040228 Optical observations
  57. IPN triangulation of GRB040228 (H3066, H3067)
  58. GRB040228 : KISO optical follow-up observation
  59. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  60. GRB 040223: Deep NIR NTT observations
  61. GRB 040223 : Optical observation (non-detection)
  62. XMM-Newton Images of GRB 040223
  63. GRB 040223, VLA observations
  64. GRB 040223: REM IJK Observations
  65. GRB 040223 XMM-Newton observation ...
  66. GRB 031203 XMM-Newton observation
  67. GRB 040223 : Planned XMM-Newton observation
  68. GRB 040106 : Planned XMM-Newton observation
  69. GRB 040223: further offline analysis
  70. GRB 040223: a long GRB detected with INTEGRAL
  71. GRB031111, optical observations
  72. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  73. GRB031203: Chandra Observations
  74. GRB040106, follow-up radio observations
  75. GRB040106: refined X-ray transient position
  76. Follow-up on IBAS GRB Alert 1379
  77. IBAS GRB alert 1379
  78. SN 2003dh/GRB030329 late-time optical spectroscopy
  79. GRB040106, Radio Observations
  80. GRB040106, likely optical afterglow
  81. GRB040106: Second Epoch Optical Observations
  82. GRB 031220: Optical observations of Chandra X-ray sources
  83. XMM-Newton Images of GRB 040106
  84. GRB040106: optical observations with REM+ROSS
  85. GRB031220: observation at Univercity of Miyazaki
  86. GRB 040106: Optical observations
  87. XMM-Newton observation of GRB040106
  88. GRB 040106 : Planned XMM-Newton observation
  89. GRB 040106 : peak flux
  90. GRB 040106 : a long GRB detected with INTEGRAL
  91. IPN triangulation of an intermediate burst from SGR1806-20
  92. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  93. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  94. GRB031225a triangulation (annulus)
  95. IPN triangulation of GRB031219 (large error box)
  96. GRB031220: Palomar Observations
  97. GRB 031220 : Kyoto Optical Observation
  98. GRB 031220: Subaru observation
  99. GRB 031220: Optical observation at Tokyo Tech
  100. GRB031220: ROTSE-IIIb Optical Limits

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