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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"

37512 results found.

  1. GRB 030323: Gemini South VRI obsevations.
  2. GRB030329: Optical observations
  3. GRB 030329, R-band observations, supplement
  4. GRB030329:optical observations by MASTER
  5. GRB 030329: optical observations
  6. GRB 030329, R-band observations
  7. GRB 030329: OT B and R photometry, decline rate
  8. GRB030329: Upper limits from recent and historical observations.
  9. GRB030329 (=H2652): A Long, Extremely Bright GRB Localized by the HETE WXM and SXC
  10. RXTE detection of GRB 030329 afterglow
  11. GRB 030329: Optical Afterglow Observations
  12. GRB 030329: precise position from Kyoto images
  13. GRB 030328 Optical Observations
  14. GRB 030328: Optical observations
  15. GRB 030328: optical observations
  16. GRB 030329: Optical afterglow fading
  17. GRB 030329 follow-up
  18. GRB 030329: Optical afterglow candidate
  19. GRB 030329: OT candidate
  20. GRB 030329: Optical afterglow candidate
  21. GRB 030328: OT photometry
  22. VLT spectra of GRB 030328
  23. GRB 030328, optical spectroscopy
  24. GRB 030328, optical observations
  25. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  26. GRB 030328: Optical observations
  27. Re: GRB 030328: Finding chart
  28. GRB 030328: Finding chart
  29. GRB 030328: Optical afterglow candidate
  30. GRB030131, BVRcIc field photometry
  31. Possible GRB030323 localized by INTEGRAL
  32. IPN triangulation of GRB030325 (final analysis)
  33. IPN triangulation of GRB030326 (single small error box)
  34. GRB 030323: SARA Optical Observations
  35. IPN triangulation of GRB030325 (single small error box)
  36. GRB030324, optical observations
  37. IPN triangulation of GRB030325 (two small error boxes)
  38. GRB 030324: TAROT optical observations
  39. GRB 030324 (HETE #2641): Optical observations
  40. GRB030324, Optical Observations
  41. GRB030323: Upper limits from recent and historical observations.
  42. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  43. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  44. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  45. VLT/FORS2 spectra of GRB 030323
  46. GRB030323, ROTSE-III detection of possible optical counterpart
  47. GRB030323, optical observations
  48. GRB030324, BVRcIc field photometry
  49. GRB030323, possible optical counterpart
  50. GRB030323, BVRcIc field calibration
  51. GRB 030324 optical observations
  52. GRB 030320: Optical Observations
  53. GRB 030324, optical observations
  54. IPN triangulation of GRB030320B (annulus)
  55. IPN triangulation of GRB030320 (small error box)
  56. IPN triangulation of GRB030320
  57. Possible GRB 030320 localized by INTEGRAL
  58. IPN upper limit to a GRB associated with SN2003L
  59. IPN triangulation of GRB030317 (annulus)
  60. IPN triangulation of GRB030307 (annulus)
  61. GRB 030227: Optical limit at RIKEN
  62. GRB 030226 Optical observations
  63. IPN triangulation of GRB030306 (single small error box - REVISED)
  64. GRB030226: Optical observations at Asiago
  65. IPN triangulation of GRB030306 (single small error box)
  66. IPN triangulation of GRB030306 (two small error boxes)
  67. IPN triangulation of GRB030306 (intense; annulus only so far)
  68. GRB 030226: Optical observations
  69. IPN triangulation of GRB030304 (annulus)
  70. GRB 030227: Optical observations
  71. GRB030226, BVRc observations
  72. Chandra detection of the X-ray afterglow of GRB 030226
  73. GRB 030226, further optical/NIR imaging
  74. GRB030227, optical observations
  75. GRB 030226: Ic Observations
  76. GRB030227: Kiso optical upper limit
  77. IPN triangulation of GRB030301 (annulus)
  78. IPN triangulation of GRB030228 (annulus)
  79. GRB030227, BVRcIc field photometry
  80. GRB030226, BVRcIc field calibration
  81. GRB 030227 optical afterglow
  82. 030302: NOT A GRB
  83. 030228: NOT A GRB
  84. GRB 030228, optical observations
  85. GRB 030226: Steep Decline
  86. GRB 030227: Confirmed Optical Afterglow (S1-A)
  87. GRB 030226: R band polarimetric observations
  88. GRB 030226: Optical observations
  89. GRB 030227: fading of candidate optical afterglow 'S1-A'
  90. GRB030227:Optical observations
  91. GRB 20030226: Upper limits from recent and historical observations
  92. GRB 030227, possible optical counterpart of XMM-Newton source
  93. GRB030227 - faint tentative OT candidate
  94. GRB 030226, optical observations
  95. GRB030227: Kiso optical observations
  96. GRB 030227: Kyoto optical observation
  97. GRB 030226, optical light curve
  98. GRB 030226 spectroscopy
  99. Possible break in the GRB 030226 light curve
  100. GRB 030226 : Predicted light curve

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