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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"

26528 results found.

  1. GRB 030328: Optical observations
  2. GRB 030328: Optical afterglow candidate
  3. GRB030324 optical observation
  4. GRB030131, BVRcIc field photometry
  5. Possible GRB030323 localized by INTEGRAL
  6. GRB030323: Detection on 2003/03/24
  7. IPN triangulation of GRB030326 (single small error box)
  8. IPN triangulation of GRB030325 (two small error boxes)
  9. GRB030323: V, R, I photometry
  10. GRB 030324 (HETE #2641): Optical observations
  11. GRB030324, Optical Observations
  12. GRB030323 (=H2640): A Faint, Long GRB Localized by the HETE WXM and SXC
  13. GRB030324 (=H2641): A Long GRB Localized in Real Time by the HETE WXM
  14. VLT/FORS2 spectra of GRB 030323
  15. GRB030323, optical observations
  16. GRB030324, BVRcIc field photometry
  17. GRB030323, BVRcIc field calibration
  18. GRB 030324, optical observations
  19. IPN triangulation of GRB030320 (small error box)
  20. Possible GRB 030320 localized by INTEGRAL
  21. IPN upper limit to a GRB associated with SN2003L
  22. IPN triangulation of GRB030306 (single small error box - REVISED)
  23. IPN triangulation of GRB030306 (single small error box)
  24. IPN triangulation of GRB030306 (two small error boxes)
  25. GRB030226: Analysis of Chandra data
  26. IPN triangulation of GRB030304 (annulus)
  27. GRB030226, BVRc observations
  28. Chandra detection of the X-ray afterglow of GRB 030226
  29. GRB 030226, further optical/NIR imaging
  30. GRB030227: Kiso optical upper limit
  31. GRB030227, BVRcIc field photometry
  32. GRB030226, BVRcIc field calibration
  33. GRB 030228, optical observations
  34. GRB 030227: Confirmed Optical Afterglow (S1-A)
  35. GRB 030227: fading of candidate optical afterglow 'S1-A'
  36. GRB030227:Optical observations
  37. GRB 030227, possible optical counterpart of XMM-Newton source
  38. XMM-Newton observation of GRB030227
  39. GRB030227: Kiso optical observations
  40. GRB 030227: Kyoto optical observation
  41. GRB 030226 spectroscopy
  42. GRB030227: refined INTEGRAL position
  43. GRB030227 localized by INTEGRAL
  44. GRB 030226 : Predicted light curve
  45. GRB030226: ESI spectroscopy
  46. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  47. GRB 030226 simultaneous optical observations
  48. GRB 030226, optical observations
  49. GRB030226: Optical decay index
  50. GRB030226: Candidate optical afterglow
  51. GRB: Non-Referencing of GCN Circulars.
  52. IPN triangulation of GRB030217 (small error box)
  53. GRB 030131: marginal optical detection
  54. GRB 030204: Optical Observations
  55. GRB030204 field photometry
  56. GRB020819: Kiso R and I band observations
  57. GRB030131: Candidate Optical Afterglow
  58. GRB 030204, optical observations
  59. IPN triangulation of GRB030204 (small error box)
  60. GRB 030131, optical observations
  61. GRB 030131: afterglow candidate
  62. GRB 030115, late-time optical observations
  63. GRB 020819: Host galaxy at Radio Position
  64. GRB 020819: afterglow candidate
  65. GRB 030131 optical observations
  66. GRB 030131 optical observations
  67. A long GRB detected by INTEGRAL
  68. IPN triangulation of GRB030119 (two large error boxes)
  69. GRB 030115, simultaneous observations by BOOTES-1
  70. GRB 030115: IR observations with IRSF/SIRIUS
  71. IPN triangulation of GRB030115C (large error box)
  72. GRB030115, afterglow candidate
  73. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  74. GRB 030115 : Possible IR counterpart
  75. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  76. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  77. GRB030115: R-band observations at Asiago
  78. GRB 030115: APO Optical Observations
  79. GRB 030115, no optical candidate
  80. GRB 030115, optical candidate
  81. IPN triangulation of GRB030102A (large error box)
  82. VLT spectroscopy of the probable host of GRB 021211
  83. GRB on 20030101 seen by SPI-ACS
  84. GRB 021211: Probable Host and Underlying Supernova
  85. GRB 021112: Evidence for Another Dark Optical Afterglow
  86. GRB 021219: OSN optical observations
  87. GRB021219, optical observations
  88. GRB021219, optical observation by MASTER
  89. GRB021219: a long GRB localized by INTEGRAL
  90. GRB021211: APO optical observations
  91. XRF 020903 : HST observations
  92. GRB 021201: Optical Observations
  93. GRB 021211: CTIO observations
  94. IPN triangulation of GRB021211B (two large error boxes)
  95. GRB021211, BVRI field photometry
  96. GRB021211: Optical observations in CrAO
  97. GRB 021211, optical observations
  98. GRB021211: Kiso Observations
  99. GRB 021201, optical observations
  100. GRB021211: Optical observations

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