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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 040223: a long GRB detected with INTEGRAL
  2. GRB031111, optical observations
  3. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  4. GRB031203: Chandra Observations
  5. GRB040106, follow-up radio observations
  6. GRB040106: refined X-ray transient position
  7. Follow-up on IBAS GRB Alert 1379
  8. IBAS GRB alert 1379
  9. SN 2003dh/GRB030329 late-time optical spectroscopy
  10. GRB040106, Radio Observations
  11. GRB040106, likely optical afterglow
  12. GRB040106: Second Epoch Optical Observations
  13. GRB 031220: Optical observations of Chandra X-ray sources
  14. XMM-Newton Images of GRB 040106
  15. GRB040106: optical observations with REM+ROSS
  16. GRB031220: observation at Univercity of Miyazaki
  17. GRB 040106: Optical observations
  18. XMM-Newton observation of GRB040106
  19. GRB 040106 : Planned XMM-Newton observation
  20. GRB 040106 : peak flux
  21. GRB 040106 : a long GRB detected with INTEGRAL
  22. IPN triangulation of an intermediate burst from SGR1806-20
  23. GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
  24. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  25. GRB031225a triangulation (annulus)
  26. IPN triangulation of GRB031219 (large error box)
  27. GRB031220: Palomar Observations
  28. GRB 031220 : Kyoto Optical Observation
  29. GRB 031220: Subaru observation
  30. GRB 031220: Optical observation at Tokyo Tech
  31. GRB031220: ROTSE-IIIb Optical Limits
  32. GRB031220 : Optical Observation of Lulin Observatory
  33. GRB 031203 I-band monitoring
  34. IPN triangulation of GRB031214 (short/hard; very intense; small error box)
  35. GRB 2974 follow-up observations
  36. GRB031203, improved XMM position
  37. GRB 031203: Discovery of a dust echo
  38. GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
  39. GRB030921 triangulation (annulus)
  40. GRB 031203: SMARTS optical monitoring
  41. GRB 021203: A Normal GRB viewed far off axis?
  42. XMM-Newton Observations of GRB031203: Preliminary Images
  43. GRB 031203: Variable Radio Source
  44. GRB 031203: Magellan spectrum of possible GRB host
  45. GRB 031203: Optical/IR Astrometry
  46. IPN/HETE localization of GRB031203B (=H2949; large error box)
  47. GRB031203 K prime photometry: correction to galaxy coordinates
  48. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  49. XMM-Newton Observation of GRB031203
  50. GRB 031203: Deep NIR NTT & VLT observations
  51. GRB031203: K' Photometry of the likely GRB host
  52. XMM-Newton Observation of GRB031203
  53. GRB 031203: Radio detection
  54. GRB 031203: Further reports on December 4 observations
  55. GRB 031203: IR NTTobservations do not confirm REM detection
  56. GRB031203 : Optical Observation of Lulin Observatory
  57. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  58. GRB 031203: Apparent Spectral Break
  59. GRB031203: Planned XMM-Newton observation II
  60. GRB 031203: IR REM Observations
  61. GRB031203: Optical Observations
  62. GRB 031203 XMM-Newton observation
  63. GRB 031203: Optical/IR SMARTS Observations
  64. GRB031203: Planned XMM-Newton observation
  65. IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
  66. GRB 031203: further analysis of INTEGRAL data
  67. GRB 031203: A long GRB detected with INTEGRAL
  68. IPN triangulation of GRB031201 (large error box)
  69. IPN triangulation of GRB031130 (large error box)
  70. GRB031111A, prompt optical observations
  71. GRB 030329: Planned XMM-Newton Observation
  72. IPN triangulation of GRB031120 (two large error boxes)
  73. GRB 031111B (= H2925) : Kyoto Optical Observation
  74. IPN/HETE localization of GRB031109 (=H2917; large error box)
  75. IPN detection of activity from SGR1806-20
  76. GRB 031111, Radio observations
  77. IPN triangulation of GRB031114 (large error box)
  78. IPN triangulation of GRB031107 (two large error boxes)
  79. GRB 031111: Optical observations
  80. GRB 031111, optical observations
  81. SN 2003jd (SN/GRB?) -- X-ray Observations
  82. HETE Prompt GRB Spectral Analyses
  83. IPN triangulation of GRB031111 (=H2924): small error box
  84. XRF031109 (=H2919): A very long XRF localized by HETE
  85. IPN triangulation of GRB031108 (large error box)
  86. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  87. GRB030929/SN2003jd association unlikely based on IPN localiztion
  88. IPN triangulation of GRB031027 (small error box)
  89. IPN triangulation of GRB031026B (large error box)
  90. Lulin optical follow-up observations of GRB031026
  91. SN 2003jd (SN/GRB?), Radio Observations
  92. SN 2003jd (SN/GRB?) - possible association with GRB 030929
  93. GRB 031026: Further Ic Observations
  94. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  95. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  96. IPN triangulation of GRB031024 (single error box)
  97. GRB031026 (=H2882): A Long, Hard Spectrum Burst Localized by HETE
  98. GRB 031026: Ic Observations
  99. GRB031026 : KISO optical follow-up observation
  100. IPN triangulation of GRB031024 (annulus)

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