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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"

15728 results found.

  1. GRB 030329: Optical Decay
  2. Redshift of GRB 030329
  3. GRB030329: ROTSE network observes steepening of decay curve
  4. GRB 030329, optical photometry
  5. GRB 030329: Optical decay and synthesis
  6. GRB030329 optical observations
  7. GRB030329: optical spectroscopy with the TNG
  8. GRB 030329: Radio Observations
  9. GRB 030329, optical spectroscopy
  10. GRB 030329: still bright
  11. GRB 030329: Optical pre-Imaging
  12. GRB 030329: visual observations
  13. GRB 030329: Upper limit from 5.6 hours before trigger
  14. GRB030328: R optical observation
  15. GRB030328: X-ray Afterglow Observed with Chandra
  16. GRB 030323: Gemini South VRI obsevations.
  17. GRB030329: Optical observations
  18. GRB030329 optical observations
  19. GRB030329:optical observations by MASTER
  20. GRB 030329: optical observations
  21. GRB030329: Upper limits from recent and historical observations.
  22. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  23. GRB 030329: Optical Afterglow Observations
  24. GRB 030329: precise position from Kyoto images
  25. GRB 030328 Optical Observations
  26. GRB 030328: Optical observations
  27. GRB 030328: optical observations
  28. GRB 030329: Optical afterglow fading
  29. GRB 030329: Optical afterglow candidate
  30. GRB 030329: Optical afterglow candidate
  31. GRB030328: optical spectroscopy at TNG
  32. GRB030328: optical photometry at the TNG
  33. VLT spectra of GRB 030328
  34. GRB 030328, optical spectroscopy
  35. GRB 030328, optical observations
  36. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  37. GRB 030328: Optical observations
  38. GRB 030328: Finding chart
  39. GRB 030328: Optical afterglow candidate
  40. GRB030323 optical observations
  41. GRB030324 optical observation
  42. GRB030323: Detection on 2003/03/24
  43. GRB 030323: SARA Optical Observations
  44. GRB030324, optical observations
  45. GRB030324, optical observations
  46. GRB 030324: TAROT optical observations
  47. GRB 030324 (HETE #2641): Optical observations
  48. GRB030324, Optical Observations
  49. GRB030323: Upper limits from recent and historical observations.
  50. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  51. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  52. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  53. GRB030323, ROTSE-III detection of possible optical counterpart
  54. GRB030323, optical observations
  55. GRB030323, possible optical counterpart
  56. GRB 030324 optical observations
  57. GRB 030320: Optical Observations
  58. GRB 030324, optical observations
  59. GRB 030227: Optical limit at RIKEN
  60. GRB 030226 Optical observations
  61. GRB030226: Optical observations at Asiago
  62. GRB 030226: Optical observations
  63. GRB 030227: Optical observations
  64. GRB030226, BVRc observations
  65. Chandra detection of the X-ray afterglow of GRB 030226
  66. GRB 030226, further optical/NIR imaging
  67. GRB030227, optical observations
  68. GRB 030226: Ic Observations
  69. GRB030227: Kiso optical upper limit
  70. GRB030227, BVRcIc field photometry
  71. GRB030226, BVRcIc field calibration
  72. GRB 030227 optical afterglow
  73. GRB 030228, optical observations
  74. GRB 030226: Steep Decline
  75. GRB 030227: Confirmed Optical Afterglow (S1-A)
  76. GRB 030226: R band polarimetric observations
  77. GRB 030226: Optical observations
  78. GRB 030227: fading of candidate optical afterglow 'S1-A'
  79. GRB030227:Optical observations
  80. GRB 20030226: Upper limits from recent and historical observations
  81. GRB 030227, possible optical counterpart of XMM-Newton source
  82. GRB030227 - faint tentative OT candidate
  83. GRB 030226, optical observations
  84. GRB030227: Kiso optical observations
  85. GRB 030227: Kyoto optical observation
  86. GRB 030226, optical light curve
  87. GRB 030226 spectroscopy
  88. GRB 030226 : Predicted light curve
  89. GRB030226: optical observation
  90. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  91. GRB 030226 simultaneous optical observations
  92. GRB 030226, optical observations
  93. GRB030226: optical observations and refined redshift
  94. GRB030226: Optical decay index
  95. GRB 030226 Optical Spectra and R,I,z' Imaging
  96. GRB 030226, optical observations
  97. GRB 030226: Optical afterglow
  98. GRB030226: Candidate optical afterglow
  99. GRB 030217: Optical Observations at 4, 5, and 6 Days
  100. GRB030217: optical observations

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