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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"

18139 results found.

  1. GRB 030226, optical observations
  2. GRB030226: Optical decay index
  3. GRB 030131: marginal optical detection
  4. GRB 030204: Optical Observations
  5. GRB030204 field photometry
  6. GRB020819: Kiso R and I band observations
  7. GRB030131: Candidate Optical Afterglow
  8. GRB 030131, optical observations
  9. GRB 030131: afterglow candidate
  10. GRB 030115, late-time optical observations
  11. GRB 020819: Host galaxy at Radio Position
  12. GRB 030131 optical observations
  13. GRB 030131 optical observations
  14. A long GRB detected by INTEGRAL
  15. GRB 030115, simultaneous observations by BOOTES-1
  16. GRB 030115: IR observations with IRSF/SIRIUS
  17. GRB030115, afterglow candidate
  18. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  19. GRB 030115 : Possible IR counterpart
  20. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  21. GRB 030115: APO Optical Observations
  22. Information about where HETE will be pointing
  23. IPN triangulation of GRB030102B (portion of annulus)
  24. VLT spectroscopy of the probable host of GRB 021211
  25. GRB 021211: Probable Host and Underlying Supernova
  26. GRB 021112: Evidence for Another Dark Optical Afterglow
  27. GRB 021219: OSN optical observations
  28. GRB021219, optical observations
  29. GRB021219, optical observation by MASTER
  30. GRB021219: a long GRB localized by INTEGRAL
  31. GRB021211: APO optical observations
  32. IPN triangulation of GRB021215 (large error box)
  33. XRF 020903 : HST observations
  34. GRB 021201: Optical Observations
  35. GRB 021211: CTIO observations
  36. GRB021211, BVRI field photometry
  37. GRB021211: Optical observations in CrAO
  38. GRB 021211, optical observations
  39. GRB021211: Kiso Observations
  40. GRB 021201, optical observations
  41. GRB021211: Optical observations
  42. GRB 021201 (short/hard), NOT observations
  43. Chandra observation of the IPN error box of GRB021201 (short/hard)
  44. GRB 021211, R- and I-band observations
  45. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  46. HETE 2493: Optical observations
  47. HETE 2493: Optical candidate
  48. GRB021201, BVRcIc field photometry
  49. GRB 021201: Optical Observations
  50. GRB 021201: BOOTES simultaneous optical observations
  51. IPN triangulation of GRB021201 (short/hard burst, small error box)
  52. GRB021004, late time optical observations
  53. IPN triangulation of GRB021119 (large error box)
  54. Improved IPN error box for GRB021125
  55. GRB021125 : A long GRB localized by INTEGRAL
  56. GRB 021112: Afterglow or Variable Star?
  57. GRB021113: optical observations at Bisei
  58. GRB021112, BVRI field photometry
  59. GRB 021112: Variable Source in R-band search
  60. GRB021112: Optical Observations
  61. GRB 021113: Optical observations
  62. GRB 021112: RAPTOR Observations
  63. GRB021113 (=H2449): A Long GRB Localized by HETE
  64. GRB021112 (=H2448): A Long GRB Localized by HETE
  65. GRB 021016: Optical Observations
  66. GRB021004: Near infrared spectroscopy
  67. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  68. SGR1900+14 activity, November 2-4, 2002
  69. GRB021104: optical observations
  70. Detection of activity from SGR 1900+14 with the RXTE/PCA
  71. IPN triangulation of GRB021027 (single large error box)
  72. GRB 021004: optical observations
  73. GRB021004: Optical Observations
  74. GRB021016(=H2397): A Long GRB Localized by HETE
  75. IPN triangulation of GRB021014 (large error box)
  76. IPN triangulation of GRB021013 (two small error boxes)
  77. XRF 020903: flattening of the optical light curve.
  78. GRB021004, UBVRcIc field photometry update
  79. IPN triangulation of GRB021008 (single error box)
  80. IPN triangulation of GRB021008 (two small error boxes)
  81. GRB021004 Chandra HETG Observations
  82. GRB 021004: Optical/NIR Observations
  83. GRB 021004: Additional V-band Polarimetric Observations
  84. GRB021004: optical observation
  85. GRB 021004: Host Galaxy Star Formation Rate
  86. GRB 021004: WC wind?
  87. GRB021004: NIR and Optical observations
  88. IPN triangulation of GRB021007 (annulus)
  89. XRF 020903 spectrum
  90. GRB021004: BVRc photometry
  91. GRB 021004 redshift
  92. GRB021004 radio observation
  93. HETE fluences for GRB021004
  94. GRB 021004: Optical Photometry at 2.5 Days
  95. GRB 021004: polarimetric observations
  96. GRB 021004: V-band Polarimetric Observations
  97. GRB021004: Update Bisei photometric data
  98. GRB 021004: Optical Decay
  99. GRB 021004 radio observation
  100. GRB 021004: Optical Photometry at 1.5 Days

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