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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"

42554 results found.

  1. GRB030328: X-ray Afterglow Observed with Chandra
  2. GRB 030323: Gemini South VRI obsevations.
  3. GRB030329: Optical observations
  4. GRB030329 optical observations
  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 030328 Optical Observations
  13. GRB030328: Decay index
  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. GRB030328: optical spectroscopy at TNG
  23. GRB030328: optical photometry at the TNG
  24. VLT spectra of GRB 030328
  25. GRB 030328, optical spectroscopy
  26. GRB 030328, optical observations
  27. GRB030328 (=H2650): A Long, Bright GRB Localized by the HETE WXM and SXC
  28. GRB 030328: Optical observations
  29. GRB 030328: Finding chart
  30. GRB 030328: Optical afterglow candidate
  31. GRB030324 optical observation
  32. GRB030131, BVRcIc field photometry
  33. Possible GRB030323 localized by INTEGRAL
  34. IPN triangulation of GRB030325 (final analysis)
  35. GRB030323: Detection on 2003/03/24
  36. IPN triangulation of GRB030326 (single small error box)
  37. GRB 030323: SARA Optical Observations
  38. IPN triangulation of GRB030325 (single small error box)
  39. GRB030324, optical observations
  40. GRB030324, optical observations
  41. IPN triangulation of GRB030325 (two small error boxes)
  42. GRB 030324: TAROT optical observations
  43. GRB030323: V, R, I photometry
  44. GRB030324, Optical Observations
  45. GRB030323: Upper limits from recent and historical observations.
  46. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  47. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  48. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  49. VLT/FORS2 spectra of GRB 030323
  50. GRB030323, ROTSE-III detection of possible optical counterpart
  51. GRB030323, optical observations
  52. GRB030324, BVRcIc field photometry
  53. GRB030323, possible optical counterpart
  54. GRB030323, BVRcIc field calibration
  55. GRB 030324 optical observations
  56. GRB 030320: Optical Observations
  57. GRB 030324, optical observations
  58. IPN triangulation of GRB030320B (annulus)
  59. IPN triangulation of GRB030320 (small error box)
  60. IPN triangulation of GRB030320
  61. Possible GRB 030320 localized by INTEGRAL
  62. GRB030226, addendum to GCN 1892
  63. IPN upper limit to a GRB associated with SN2003L
  64. IPN triangulation of GRB030317 (annulus)
  65. IPN triangulation of GRB030307 (annulus)
  66. GRB 030227: Optical limit at RIKEN
  67. GRB 030226 Optical observations
  68. IPN triangulation of GRB030306 (single small error box - REVISED)
  69. GRB030226: Optical observations at Asiago
  70. IPN triangulation of GRB030306 (single small error box)
  71. IPN triangulation of GRB030306 (two small error boxes)
  72. IPN triangulation of GRB030306 (intense; annulus only so far)
  73. GRB 030226: Optical observations
  74. GRB030226: Analysis of Chandra data
  75. IPN triangulation of GRB030304 (annulus)
  76. GRB 030227: Optical observations
  77. GRB030226, BVRc observations
  78. Chandra detection of the X-ray afterglow of GRB 030226
  79. GRB 030226, further optical/NIR imaging
  80. GRB 030226: Ic Observations
  81. GRB030227: Kiso optical upper limit
  82. IPN triangulation of GRB030301 (annulus)
  83. IPN triangulation of GRB030228 (annulus)
  84. GRB030227, BVRcIc field photometry
  85. GRB030226, BVRcIc field calibration
  86. GRB 030227 optical afterglow
  87. 030302: NOT A GRB
  88. 030228: NOT A GRB
  89. GRB 030228, optical observations
  90. GRB 030226: Steep Decline
  91. GRB 030227: Confirmed Optical Afterglow (S1-A)
  92. GRB 030226: R band polarimetric observations
  93. GRB 030226: Optical observations
  94. GRB 030227: fading of candidate optical afterglow 'S1-A'
  95. GRB030227:Optical observations
  96. GRB 20030226: Upper limits from recent and historical observations
  97. GRB 030227, possible optical counterpart of XMM-Newton source
  98. GRB030227 - faint tentative OT candidate
  99. GRB 030226, optical observations
  100. XMM-Newton observation of GRB030227

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