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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"

28042 results found.

  1. GRB030329: Kiso B and R band observations
  2. GRB030328: R upper limit after 6 hours by MASTER
  3. SDSS 0.5m PT observations of GRB030329 (correction)
  4. SDSS 0.5m PT observations of GRB030329
  5. GRB030329: final R-band light curve by MASTER
  6. GRB030329, optical observation
  7. GRB030329, new UBVRcIc field photometry
  8. GRB 030329, light curve and SN prediction
  9. GRB 030329, BRI photometry
  10. GRB030328: Full Observation, X-ray Fading and Spectrum Measured
  11. GRB030329: Optical observations at Teramo
  12. GRB 030329: Radio observations at GMRT
  13. Further AAVSO V,B,R observations of GRB030329
  14. GRB 030329: Additional Mt. Laguna Optical Observations
  15. GRB 030329: Observations with ANDICAM
  16. GRB030329: further optical photometry and evidence for a light curve discontinuity
  17. triangulation of GRB 030331 (single error box)
  18. GRB 030329: optical observations
  19. Photometry of GRB030329 - Constant OT Magnitude
  20. GRB030329 - OT brightens
  21. GRB 030329, optical photometry
  22. GRB 030324: Optical and NIR Observations
  23. GRB030329: R band light curve by MASTER
  24. GRB030329 - Light curve flattening
  25. GRB 030324, optical search
  26. GRB 030329, optical observations
  27. GRB030328: X-ray Fading and Spectrum Measured with Chandra
  28. GRB030329a: detection by Konus-Wind
  29. GRB030329b: detection by Konus-Wind and Helicon-CoronasF
  30. GRB030329, BVRcIc field photometry
  31. GRB030329, SPM optical observations
  32. GRB 030329: Optical decay and synthesis
  33. GRB030329 optical observations
  34. GRB 030329: Optical pre-Imaging
  35. GRB 030329: Upper limit from 5.6 hours before trigger
  36. GRB030328: X-ray Afterglow Observed with Chandra
  37. GRB 030329, R-band observations
  38. GRB 030329: OT B and R photometry, decline rate
  39. GRB030329: Upper limits from recent and historical observations.
  40. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  41. GRB 030329: Optical Afterglow Observations
  42. GRB 030328: optical observations
  43. GRB 030329: Optical afterglow fading
  44. GRB 030328: OT photometry
  45. GRB030328: optical spectroscopy at TNG
  46. GRB030328: optical photometry at the TNG
  47. VLT spectra of GRB 030328
  48. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  49. GRB 030328: Optical observations
  50. GRB030324 optical observation
  51. GRB030131, BVRcIc field photometry
  52. Possible GRB030323 localized by INTEGRAL
  53. GRB030323: Detection on 2003/03/24
  54. IPN triangulation of GRB030326 (single small error box)
  55. IPN triangulation of GRB030325 (two small error boxes)
  56. GRB030323: V, R, I photometry
  57. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  58. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  59. VLT/FORS2 spectra of GRB 030323
  60. GRB030323, optical observations
  61. GRB030324, BVRcIc field photometry
  62. GRB030323, BVRcIc field calibration
  63. IPN triangulation of GRB030320 (small error box)
  64. Possible GRB 030320 localized by INTEGRAL
  65. IPN triangulation of GRB030306 (single small error box - REVISED)
  66. IPN triangulation of GRB030306 (single small error box)
  67. IPN triangulation of GRB030306 (two small error boxes)
  68. GRB030226, BVRc observations
  69. Chandra detection of the X-ray afterglow of GRB 030226
  70. GRB030227: Kiso optical upper limit
  71. GRB030227, BVRcIc field photometry
  72. GRB030226, BVRcIc field calibration
  73. GRB 030228, optical observations
  74. GRB 030227: Confirmed Optical Afterglow (S1-A)
  75. GRB 030227: fading of candidate optical afterglow 'S1-A'
  76. GRB030227:Optical observations
  77. GRB 030227, possible optical counterpart of XMM-Newton source
  78. GRB030227 - faint tentative OT candidate
  79. GRB 030226, optical observations
  80. XMM-Newton observation of GRB030227
  81. GRB030227: Kiso optical observations
  82. GRB 030227: Kyoto optical observation
  83. GRB 030226, optical light curve
  84. GRB030227 localized by INTEGRAL
  85. GRB 030226 : Predicted light curve
  86. GRB030226: ESI spectroscopy
  87. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  88. GRB 030226 simultaneous optical observations
  89. GRB 030226, optical observations
  90. GRB030226: Optical decay index
  91. GRB 030226 Optical Spectra and R,I,z' Imaging
  92. GRB: Non-Referencing of GCN Circulars.
  93. IPN triangulation of GRB030217 (small error box)
  94. GRB 030131: marginal optical detection
  95. GRB 030204: Optical Observations
  96. GRB030204 field photometry
  97. GRB020819: Kiso R and I band observations
  98. GRB030131: Candidate Optical Afterglow
  99. IPN triangulation of GRB030204 (small error box)
  100. GRB 030131, optical observations

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