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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"

36144 results found.

  1. GRB 030329 RBO V Optical Observations
  2. GRB 030329, optical photometry
  3. GRB030329: Near Infrared Observations
  4. 030331 NOT A GRB
  5. INTEGRAL GRB 030331
  6. GRB 030324: Optical and NIR Observations
  7. GRB 030328, optical photometry
  8. GRB030329: R band light curve by MASTER
  9. GRB030329 - Light curve flattening
  10. GRB 030329: SARA Optical Observations
  11. GRB 030324, optical search
  12. GRB030329 - near contemporaneous optical limits from CONCAM
  13. GRB 030329, optical observations
  14. GRB 030329: Light curve observed during the change of its slope.
  15. GRB030329, BVRcIc field photometry
  16. GRB030329, SPM optical observations
  17. GRB 030329: Optical Decay
  18. Redshift of GRB 030329
  19. GRB030329: ROTSE network observes steepening of decay curve
  20. GRB 030329, optical photometry
  21. GRB 030329: Optical decay and synthesis
  22. GRB 030329: Radio Observations
  23. GRB 030329, optical spectroscopy
  24. GRB 030329: still bright
  25. GRB 030329: Optical pre-Imaging
  26. GRB 030329: visual observations
  27. GRB 030329: Upper limit from 5.6 hours before trigger
  28. GRB030328: R optical observation
  29. GRB 030323: Gemini South VRI obsevations.
  30. GRB030329: Optical observations
  31. GRB 030329, R-band observations, supplement
  32. GRB030329:optical observations by MASTER
  33. GRB 030329: optical observations
  34. GRB 030329, R-band observations
  35. GRB 030329: OT B and R photometry, decline rate
  36. GRB030329: Upper limits from recent and historical observations.
  37. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  38. RXTE detection of GRB 030329 afterglow
  39. GRB 030329: Optical Afterglow Observations
  40. GRB 030329: precise position from Kyoto images
  41. GRB 030328 Optical Observations
  42. GRB 030328: Optical observations
  43. GRB 030328: optical observations
  44. GRB 030329: Optical afterglow fading
  45. GRB 030329 follow-up
  46. GRB 030329: Optical afterglow candidate
  47. GRB 030329: OT candidate
  48. GRB 030329: Optical afterglow candidate
  49. GRB 030328: OT photometry
  50. VLT spectra of GRB 030328
  51. GRB 030328, optical spectroscopy
  52. GRB 030328, optical observations
  53. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  54. GRB 030328: Optical observations
  55. Re: GRB 030328: Finding chart
  56. GRB 030328: Finding chart
  57. GRB 030328: Optical afterglow candidate
  58. GRB030131, BVRcIc field photometry
  59. Possible GRB030323 localized by INTEGRAL
  60. IPN triangulation of GRB030325 (final analysis)
  61. IPN triangulation of GRB030326 (single small error box)
  62. GRB 030323: SARA Optical Observations
  63. IPN triangulation of GRB030325 (single small error box)
  64. GRB030324, optical observations
  65. IPN triangulation of GRB030325 (two small error boxes)
  66. GRB 030324: TAROT optical observations
  67. GRB 030324 (HETE #2641): Optical observations
  68. GRB030324, Optical Observations
  69. GRB030323: Upper limits from recent and historical observations.
  70. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  71. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  72. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  73. VLT/FORS2 spectra of GRB 030323
  74. GRB030323, ROTSE-III detection of possible optical counterpart
  75. GRB030323, optical observations
  76. GRB030324, BVRcIc field photometry
  77. GRB030323, possible optical counterpart
  78. GRB030323, BVRcIc field calibration
  79. GRB 030324 optical observations
  80. GRB 030320: Optical Observations
  81. GRB 030324, optical observations
  82. IPN triangulation of GRB030320B (annulus)
  83. IPN triangulation of GRB030320 (small error box)
  84. IPN triangulation of GRB030320
  85. Possible GRB 030320 localized by INTEGRAL
  86. IPN upper limit to a GRB associated with SN2003L
  87. IPN triangulation of GRB030317 (annulus)
  88. IPN triangulation of GRB030307 (annulus)
  89. GRB 030227: Optical limit at RIKEN
  90. GRB 030226 Optical observations
  91. IPN triangulation of GRB030306 (single small error box - REVISED)
  92. GRB030226: Optical observations at Asiago
  93. IPN triangulation of GRB030306 (single small error box)
  94. IPN triangulation of GRB030306 (two small error boxes)
  95. IPN triangulation of GRB030306 (intense; annulus only so far)
  96. GRB 030226: Optical observations
  97. IPN triangulation of GRB030304 (annulus)
  98. GRB 030227: Optical observations
  99. GRB030226, BVRc observations
  100. Chandra detection of the X-ray afterglow of GRB 030226

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