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

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