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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"

19551 results found.

  1. GRB 030228, optical observations
  2. GRB 030227: Confirmed Optical Afterglow (S1-A)
  3. GRB 030226: Optical observations
  4. GRB 030227: fading of candidate optical afterglow 'S1-A'
  5. GRB030227:Optical observations
  6. GRB 030227, possible optical counterpart of XMM-Newton source
  7. GRB030227: Kiso optical observations
  8. GRB 030227: Kyoto optical observation
  9. GRB030227: refined INTEGRAL position
  10. GRB030227 localized by INTEGRAL
  11. GRB030226: ESI spectroscopy
  12. GRB 030226 simultaneous optical observations
  13. GRB 030226, optical observations
  14. GRB030226: Optical decay index
  15. GRB 030131: marginal optical detection
  16. GRB 030204: Optical Observations
  17. GRB030204 field photometry
  18. GRB020819: Kiso R and I band observations
  19. GRB030131: Candidate Optical Afterglow
  20. GRB 030131, optical observations
  21. GRB 030131: afterglow candidate
  22. GRB 030115, late-time optical observations
  23. GRB 020819: Host galaxy at Radio Position
  24. GRB 030131 optical observations
  25. GRB 030131 optical observations
  26. A long GRB detected by INTEGRAL
  27. GRB 030115, simultaneous observations by BOOTES-1
  28. GRB 030115: IR observations with IRSF/SIRIUS
  29. GRB030115, afterglow candidate
  30. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  31. GRB 030115 : Possible IR counterpart
  32. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  33. GRB 030115: APO Optical Observations
  34. Information about where HETE will be pointing
  35. IPN triangulation of GRB030102B (portion of annulus)
  36. VLT spectroscopy of the probable host of GRB 021211
  37. GRB 021211: Probable Host and Underlying Supernova
  38. GRB 021112: Evidence for Another Dark Optical Afterglow
  39. GRB 021219: OSN optical observations
  40. GRB021219, optical observations
  41. GRB021219, optical observation by MASTER
  42. GRB021219: a long GRB localized by INTEGRAL
  43. GRB021211: APO optical observations
  44. IPN triangulation of GRB021215 (large error box)
  45. XRF 020903 : HST observations
  46. GRB 021201: Optical Observations
  47. GRB 021211: CTIO observations
  48. GRB021211, BVRI field photometry
  49. GRB021211: Optical observations in CrAO
  50. GRB 021211, optical observations
  51. GRB021211: Kiso Observations
  52. GRB 021201, optical observations
  53. GRB021211: Optical observations
  54. GRB 021201 (short/hard), NOT observations
  55. Chandra observation of the IPN error box of GRB021201 (short/hard)
  56. GRB 021211, R- and I-band observations
  57. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  58. HETE 2493: Optical observations
  59. HETE 2493: Optical candidate
  60. GRB021201, BVRcIc field photometry
  61. GRB 021201: Optical Observations
  62. GRB 021201: BOOTES simultaneous optical observations
  63. IPN triangulation of GRB021201 (short/hard burst, small error box)
  64. GRB021004, late time optical observations
  65. IPN triangulation of GRB021119 (large error box)
  66. Improved IPN error box for GRB021125
  67. GRB021125 : A long GRB localized by INTEGRAL
  68. GRB 021112: Afterglow or Variable Star?
  69. GRB021113: optical observations at Bisei
  70. GRB021112, BVRI field photometry
  71. GRB 021112: Variable Source in R-band search
  72. GRB021112: Optical Observations
  73. GRB 021113: Optical observations
  74. GRB 021112: RAPTOR Observations
  75. GRB021113 (=H2449): A Long GRB Localized by HETE
  76. GRB021112 (=H2448): A Long GRB Localized by HETE
  77. GRB 021016: Optical Observations
  78. GRB021004: Near infrared spectroscopy
  79. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  80. SGR1900+14 activity, November 2-4, 2002
  81. GRB021104: optical observations
  82. Detection of activity from SGR 1900+14 with the RXTE/PCA
  83. IPN triangulation of GRB021027 (single large error box)
  84. GRB 021004: optical observations
  85. GRB021004: Optical Observations
  86. GRB021016(=H2397): A Long GRB Localized by HETE
  87. IPN triangulation of GRB021014 (large error box)
  88. IPN triangulation of GRB021013 (two small error boxes)
  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. GRB 021004: WC wind?
  99. GRB021004: NIR and Optical observations
  100. IPN triangulation of GRB021007 (annulus)

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