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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"

20358 results found.

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

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