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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"

21793 results found.

  1. GRB 030329: optical observations
  2. GRB 030329, R-band observations
  3. GRB030329: Upper limits from recent and historical observations.
  4. GRB 030329: Optical Afterglow Observations
  5. GRB 030329: precise position from Kyoto images
  6. GRB 030328 Optical Observations
  7. GRB030328: Decay index
  8. GRB 030328: Optical observations
  9. GRB 030328: optical observations
  10. GRB 030329: Optical afterglow fading
  11. GRB 030329 follow-up
  12. GRB 030329: Optical afterglow candidate
  13. GRB 030328: OT photometry
  14. GRB030328: optical spectroscopy at TNG
  15. GRB030328: optical photometry at the TNG
  16. GRB 030328, optical observations
  17. GRB 030328: Optical observations
  18. GRB 030328: Optical afterglow candidate
  19. GRB030323 optical observations
  20. GRB 030323: SARA Optical Observations
  21. GRB030324, optical observations
  22. GRB030324, optical observations
  23. GRB 030324: TAROT optical observations
  24. GRB030323: V, R, I photometry
  25. GRB 030324 (HETE #2641): Optical observations
  26. GRB030324, Optical Observations
  27. GRB030323: Upper limits from recent and historical observations.
  28. VLT/FORS2 spectra of GRB 030323
  29. GRB030323, optical observations
  30. GRB030324, BVRcIc field photometry
  31. GRB030323, possible optical counterpart
  32. GRB030323, BVRcIc field calibration
  33. GRB 030324 optical observations
  34. GRB 030320: Optical Observations
  35. GRB 030324, optical observations
  36. GRB030226, addendum to GCN 1892
  37. GRB 030226 Optical observations
  38. GRB030226: Optical observations at Asiago
  39. GRB 030226: Optical observations
  40. GRB 030227: Optical observations
  41. GRB030226, BVRc observations
  42. GRB 030226, further optical/NIR imaging
  43. GRB030227, optical observations
  44. GRB 030226: Ic Observations
  45. GRB 030228, optical observations
  46. GRB 030226: Steep Decline
  47. GRB 030226: R band polarimetric observations
  48. GRB 030226: Optical observations
  49. GRB030227:Optical observations
  50. GRB 20030226: Upper limits from recent and historical observations
  51. GRB 030227, possible optical counterpart of XMM-Newton source
  52. GRB 030226, optical observations
  53. GRB030227: Kiso optical observations
  54. GRB 030226, optical light curve
  55. GRB030226: optical observation
  56. GRB030226: ESI spectroscopy
  57. GRB 030226 simultaneous optical observations
  58. GRB 030226, optical observations
  59. GRB030226: optical observations and refined redshift
  60. GRB030226: Optical decay index
  61. GRB 030226, optical observations
  62. GRB030226: Candidate optical afterglow
  63. GRB 030217: Optical Observations at 4, 5, and 6 Days
  64. GRB030217: optical observations
  65. GRB030115, WSRT radio observations - correction to GCN 1864
  66. GRB 030131: marginal optical detection
  67. GRB030115, WSRT radio observations
  68. GRB 030204: Optical Observations
  69. GRB020819: Kiso R and I band observations
  70. GRB030131: Candidate Optical Afterglow
  71. GRB 030115: Optical Observations
  72. GRB 030204, optical observations
  73. GRB 030131, optical observations
  74. GRB030131: Optical limits for corrected position
  75. GRB 030115, late-time optical observations
  76. GRB030131: Kiso Observations
  77. GRB 020819: Host galaxy at Radio Position
  78. GRB030131: Optical limit
  79. GRB 030131 optical observations
  80. GRB 030131 optical observations
  81. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  82. Type Ic SN2003L (SN/GRB?) Radio Observations
  83. GRB030115 submm upper limit
  84. GRB 030115: Further IR observations with IRSF/SIRIUS
  85. GRB 030115: Radio detection of IR candidate
  86. GRB 030115, simultaneous observations by BOOTES-1
  87. GRB 030115: IR observations with IRSF/SIRIUS
  88. GRB030115: R-band counterpart of IR candidate
  89. GRB 021211: R-band observations at late-time
  90. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  91. GRB 030115 : Possible IR counterpart
  92. GRB 030115: Radio Observations
  93. GRB030115: R-band observations at Asiago
  94. GRB030115: TAROT optical observations
  95. GRB 021211: VLT spectrum
  96. GRB 030115: APO Optical Observations
  97. GRB 030115, no optical candidate
  98. GRB 030115, optical observations
  99. GRB 030115, optical candidate
  100. Information about where HETE will be pointing

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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