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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"

20356 results found.

  1. GRB 030204: Optical Observations
  2. GRB030204 field photometry
  3. GRB020819: Kiso R and I band observations
  4. GRB030131: Candidate Optical Afterglow
  5. IPN triangulation of GRB030204 (small error box)
  6. GRB 030131, optical observations
  7. GRB 030131: afterglow candidate
  8. GRB 030115, late-time optical observations
  9. Type Ic SN2003L (SN/GRB?), optical spectrum
  10. GRB 020819: Host galaxy at Radio Position
  11. GRB 030131 optical observations
  12. GRB 030131 optical observations
  13. A long GRB detected by INTEGRAL
  14. GRB 030115: Further IR observations with IRSF/SIRIUS
  15. GRB 030115, simultaneous observations by BOOTES-1
  16. GRB 030115: IR observations with IRSF/SIRIUS
  17. IPN triangulation of GRB030115C (large error box)
  18. GRB030115, afterglow candidate
  19. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  20. GRB 030115 : Possible IR counterpart
  21. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  22. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  23. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  24. GRB 030115: APO Optical Observations
  25. GRB on 20030102 seen by SPI-ACS
  26. VLT spectroscopy of the probable host of GRB 021211
  27. GRB 021211: Probable Host and Underlying Supernova
  28. GRB 021112: Evidence for Another Dark Optical Afterglow
  29. GRB 021219: OSN optical observations
  30. GRB021219: Radio Observations
  31. GRB021219, optical observations
  32. GRB021219, optical observation by MASTER
  33. GRB021219 refined position with INTEGRAL
  34. GRB021219: a long GRB localized by INTEGRAL
  35. GRB021211: APO optical observations
  36. XRF 020903 : HST observations
  37. GRB 021201: Optical Observations
  38. GRB 021211: CTIO observations
  39. VLT spectrum of GRB 021211
  40. GRB021211, BVRI field photometry
  41. GRB021211: Optical observations in CrAO
  42. GRB 021211, IR observations
  43. GRB 021211, optical observations
  44. GRB021211: Kiso Observations
  45. GRB 021201, optical observations
  46. GRB021211: Optical observations
  47. GRB 021201 (short/hard), NOT observations
  48. Chandra observation of the IPN error box of GRB021201 (short/hard)
  49. GRB 021211, R- and I-band observations
  50. GRB 021204: Optical Observations at RIKEN
  51. IPN triangulation of GRB021206 (small error box)
  52. IPN triangulation of GRB021205 (large error box)
  53. GRB021201, BVRcIc field photometry
  54. GRB 021201: BOOTES simultaneous optical observations
  55. IPN triangulation of GRB021201 (short/hard burst, small error box)
  56. GRB021004, late time optical observations
  57. IPN detection of continued SGR1900+14 activity
  58. Improved IPN error box for GRB021125
  59. IPN BURST POSITION
  60. IPN triangulation of GRB021125 (INTEGRAL BURST)
  61. GRB021125 : A long GRB localized by INTEGRAL
  62. IPN confirmation of the reactivation of SGR1900+14
  63. GRB021113, SPI ACS observation
  64. GRB 021112: Afterglow or Variable Star?
  65. GRB021113: optical observations at Bisei
  66. GRB021112, BVRI field photometry
  67. GRB 021112: Variable Source in R-band search
  68. GRB021112: Optical Observations
  69. GRB 021113: Optical observations
  70. GRB 021112: RAPTOR Observations
  71. GRB 021113: Optical Observations
  72. GRB021113 (=H2449): A Long GRB Localized by HETE
  73. GRB021112 (=H2448): A Long GRB Localized by HETE
  74. GRB 021016: Optical Observations
  75. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  76. SGR1900+14 activity, November 2-4, 2002
  77. GRB021104: optical observations
  78. Detection of activity from SGR 1900+14 with the RXTE/PCA
  79. IPN triangulation of GRB021027 (single large error box)
  80. GRB 021004: optical observations
  81. IPN triangulation of GRB021023 (small error boc)
  82. IPN triangulation of GRB021020 (smaller error box)
  83. IPN triangulation of GRB021020
  84. IPN triangulation of GRB021016 (small error box)
  85. IPN triangulation of GRB021014 (large error box)
  86. IPN triangulation of GRB021013 (single error box)
  87. IPN triangulation of GRB021013 (two small error boxes)
  88. GRB021004: High-resolution optical spectroscopy
  89. XRF 020903: flattening of the optical light curve.
  90. GRB021004, UBVRcIc field photometry update
  91. IPN triangulation of GRB021008 (single error box)
  92. IPN triangulation of GRB021008 (two small error boxes)
  93. GRB021004 Chandra HETG Observations
  94. GRB 021004: Optical/NIR Observations
  95. GRB 021004: Additional V-band Polarimetric Observations
  96. GRB021004: optical observation
  97. GRB 021004: Host Galaxy Star Formation Rate
  98. GRB021004: NIR and Optical observations
  99. GRB 021004: Optical measurement at OHP
  100. GRB 021004: optical spectroscopy

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