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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 Alert 1678: not a GRB
  2. GRB 031203: spectoscopic evidence for a 1998bw-like SN
  3. GRB 031203, possible supernova
  4. MASTER: RXTE GRB040308 optical observation
  5. IBAS results on a burst from SGR1806-20
  6. INTEGRAL detection of activity from SGR1806-20
  7. RXTE GRB040229 optical observation: no candidate
  8. GRB 040228 Optical observations
  9. IPN triangulation of GRB040228 (H3066, H3067)
  10. GRB040228 : KISO optical follow-up observation
  11. GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
  12. GRB 040223: Deep NIR NTT observations
  13. GRB 040223 : Optical observation (non-detection)
  14. XMM-Newton Images of GRB 040223
  15. GRB 040223, VLA observations
  16. GRB 040223: REM IJK Observations
  17. GRB 040223 XMM-Newton observation ...
  18. GRB 031203 XMM-Newton observation
  19. GRB 040223 : Planned XMM-Newton observation
  20. GRB 040106 : Planned XMM-Newton observation
  21. GRB 040223: further offline analysis
  22. GRB 040223: a long GRB detected with INTEGRAL
  23. GRB031111, optical observations
  24. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  25. GRB031203: Chandra Observations
  26. GRB040106, follow-up radio observations
  27. GRB040106: refined X-ray transient position
  28. Follow-up on IBAS GRB Alert 1379
  29. IBAS GRB alert 1379
  30. SN 2003dh/GRB030329 late-time optical spectroscopy
  31. GRB040106, Radio Observations
  32. GRB040106, likely optical afterglow
  33. GRB040106: Second Epoch Optical Observations
  34. GRB 031220: Optical observations of Chandra X-ray sources
  35. XMM-Newton Images of GRB 040106
  36. GRB040106: optical observations with REM+ROSS
  37. GRB031220: observation at Univercity of Miyazaki
  38. GRB 040106: Optical observations
  39. XMM-Newton observation of GRB040106
  40. GRB 040106 : Planned XMM-Newton observation
  41. GRB 040106 : peak flux
  42. GRB 040106 : a long GRB detected with INTEGRAL
  43. IPN triangulation of an intermediate burst from SGR1806-20
  44. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  45. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  46. GRB031225a triangulation (annulus)
  47. IPN triangulation of GRB031219 (large error box)
  48. GRB031220: Palomar Observations
  49. GRB 031220 : Kyoto Optical Observation
  50. GRB 031220: Subaru observation
  51. GRB 031220: Optical observation at Tokyo Tech
  52. GRB031220: ROTSE-IIIb Optical Limits
  53. GRB031220 : Optical Observation of Lulin Observatory
  54. GRB 031203 I-band monitoring
  55. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  56. GRB 2974 follow-up observations
  57. GRB031203, improved XMM position
  58. GRB 031203: Discovery of a dust echo
  59. GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
  60. GRB030921 triangulation (annulus)
  61. GRB 031203: SMARTS optical monitoring
  62. GRB 021203: A Normal GRB viewed far off axis?
  63. XMM-Newton Observations of GRB031203: Preliminary Images
  64. GRB 031203: Variable Radio Source
  65. GRB 031203: Magellan spectrum of possible GRB host
  66. GRB 031203: Optical/IR Astrometry
  67. IPN/HETE localization of GRB031203B (=H2949; large error box)
  68. GRB031203 K prime photometry: correction to galaxy coordinates
  69. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  70. XMM-Newton Observation of GRB031203
  71. GRB 031203: Deep NIR NTT & VLT observations
  72. GRB031203: K' Photometry of the likely GRB host
  73. XMM-Newton Observation of GRB031203
  74. GRB 031203: Radio detection
  75. GRB 031203: Further reports on December 4 observations
  76. GRB 031203: IR NTTobservations do not confirm REM detection
  77. GRB031203 : Optical Observation of Lulin Observatory
  78. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  79. GRB 031203: Apparent Spectral Break
  80. GRB031203: Planned XMM-Newton observation II
  81. GRB 031203: IR REM Observations
  82. GRB031203: Optical Observations
  83. GRB 031203 XMM-Newton observation
  84. GRB 031203: Optical/IR SMARTS Observations
  85. GRB031203: Planned XMM-Newton observation
  86. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  87. GRB 031203: further analysis of INTEGRAL data
  88. GRB 031203: A long GRB detected with INTEGRAL
  89. IPN triangulation of GRB031201 (large error box)
  90. IPN triangulation of GRB031130 (large error box)
  91. GRB031111A, prompt optical observations
  92. GRB 030329: Planned XMM-Newton Observation
  93. IPN triangulation of GRB031120 (two large error boxes)
  94. GRB 031111B (= H2925) : Kyoto Optical Observation
  95. IPN/HETE localization of GRB031109 (=H2917; large error box)
  96. IPN detection of activity from SGR1806-20
  97. GRB 031111, Radio observations
  98. IPN triangulation of GRB031114 (large error box)
  99. IPN triangulation of GRB031107 (two large error boxes)
  100. GRB 031111: Optical observations

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