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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"

28096 results found.

  1. GRB 030329: Optical pre-Imaging
  2. GRB 030329: visual observations
  3. GRB030328: R optical observation
  4. GRB030328: X-ray Afterglow Observed with Chandra
  5. GRB 030323: Gemini South VRI obsevations.
  6. GRB 030329: optical observations
  7. GRB 030329, R-band observations
  8. RXTE detection of GRB 030329 afterglow
  9. GRB 030329: Optical Afterglow Observations
  10. GRB 030329: precise position from Kyoto images
  11. GRB 030328 Optical Observations
  12. GRB030328: Decay index
  13. GRB 030329: Optical afterglow fading
  14. GRB 030329 follow-up
  15. GRB 030329: Optical afterglow candidate
  16. GRB 030329: Optical afterglow candidate
  17. GRB030328: optical spectroscopy at TNG
  18. GRB030328: optical photometry at the TNG
  19. VLT spectra of GRB 030328
  20. GRB 030328, optical spectroscopy
  21. GRB 030328, optical observations
  22. GRB 030328: Optical observations
  23. GRB 030328: Finding chart
  24. GRB 030328: Optical afterglow candidate
  25. GRB030131, BVRcIc field photometry
  26. Possible GRB030323 localized by INTEGRAL
  27. GRB030323: Detection on 2003/03/24
  28. GRB 030323: SARA Optical Observations
  29. GRB030324, optical observations
  30. GRB030323: V, R, I photometry
  31. GRB 030324 (HETE #2641): Optical observations
  32. VLT/FORS2 spectra of GRB 030323
  33. GRB030323, ROTSE-III detection of possible optical counterpart
  34. Possible GRB 030320 localized by INTEGRAL
  35. GRB 030226 Optical observations
  36. GRB030226: Analysis of Chandra data
  37. Chandra detection of the X-ray afterglow of GRB 030226
  38. GRB 030226, further optical/NIR imaging
  39. GRB 030226: Ic Observations
  40. GRB030227: Kiso optical upper limit
  41. GRB 030227 optical afterglow
  42. GRB 030228, optical observations
  43. GRB 030226: Steep Decline
  44. GRB 030227: Confirmed Optical Afterglow (S1-A)
  45. GRB 030226: R band polarimetric observations
  46. GRB 030227: fading of candidate optical afterglow 'S1-A'
  47. GRB030227:Optical observations
  48. GRB 030227, possible optical counterpart of XMM-Newton source
  49. GRB 030226, optical observations
  50. GRB 030226, optical light curve
  51. GRB 030226 spectroscopy
  52. GRB030227 localized by INTEGRAL
  53. Possible break in the GRB 030226 light curve
  54. GRB 030226 : Predicted light curve
  55. GRB030226: optical observation
  56. GRB 030226: Confirmed decay index
  57. GRB030226: ESI spectroscopy
  58. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  59. Two absorption systems in GRB 030226
  60. GRB 030226, optical observations
  61. GRB030226: optical observations and refined redshift
  62. GRB030226: Optical decay index
  63. GRB 030226 Optical Spectra and R,I,z' Imaging
  64. GRB 030226: Optical afterglow
  65. GRB030226: Candidate optical afterglow
  66. GRB 030217: Optical Observations at 4, 5, and 6 Days
  67. GRB030115, WSRT radio observations - correction to GCN 1864
  68. GRB 030131: marginal optical detection
  69. GRB030115, WSRT radio observations
  70. GRB030204 field photometry
  71. GRB020819: Kiso R and I band observations
  72. GRB030131: Candidate Optical Afterglow
  73. GRB 030131, optical observations
  74. GRB030131: Optical limits for corrected position
  75. GRB 030131: afterglow candidate
  76. GRB 020819: afterglow candidate
  77. A long GRB detected by INTEGRAL
  78. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  79. GRB030115 submm upper limit
  80. GRB 030115: Further IR observations with IRSF/SIRIUS
  81. GRB 030115: Radio detection of IR candidate
  82. GRB 030115: IR observations with IRSF/SIRIUS
  83. GRB030115: R-band counterpart of IR candidate
  84. GRB030115, afterglow candidate
  85. GRB 021211: R-band observations at late-time
  86. GRB030115: TAROT optical observations
  87. GRB 021211: VLT spectrum
  88. GRB 030115, optical candidate
  89. GRB 021211: Probable Host and Underlying Supernova
  90. GRB021211, radio observations
  91. GRB 021112: Evidence for Another Dark Optical Afterglow
  92. VLT spectra of GRB 021211 revisited
  93. GRB021219: a long GRB localized by INTEGRAL
  94. GRB021211: APO optical observations
  95. IPN detection of continued activity from SGR1806-20
  96. GRB 021211, optical observations
  97. GRB 021211: CTIO observations
  98. GRB021211: Measurement of Early Time Afterglow
  99. VLT spectrum of GRB 021211
  100. GRB 021211: early break in light curve

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