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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"

18346 results found.

  1. GRB 030227, possible optical counterpart of XMM-Newton source
  2. GRB030227: Kiso optical observations
  3. GRB 030227: Kyoto optical observation
  4. GRB030227: refined INTEGRAL position
  5. GRB030227 localized by INTEGRAL
  6. GRB030226: ESI spectroscopy
  7. GRB 030226 simultaneous optical observations
  8. GRB 030226, optical observations
  9. GRB030226: Optical decay index
  10. GRB 030131: marginal optical detection
  11. GRB 030204: Optical Observations
  12. GRB030204 field photometry
  13. GRB020819: Kiso R and I band observations
  14. GRB030131: Candidate Optical Afterglow
  15. GRB 030131, optical observations
  16. GRB 030131: afterglow candidate
  17. GRB 030115, late-time optical observations
  18. GRB 020819: Host galaxy at Radio Position
  19. GRB 030131 optical observations
  20. GRB 030131 optical observations
  21. A long GRB detected by INTEGRAL
  22. GRB 030115, simultaneous observations by BOOTES-1
  23. GRB 030115: IR observations with IRSF/SIRIUS
  24. GRB030115, afterglow candidate
  25. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  26. GRB 030115 : Possible IR counterpart
  27. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  28. GRB 030115: APO Optical Observations
  29. Information about where HETE will be pointing
  30. IPN triangulation of GRB030102B (portion of annulus)
  31. VLT spectroscopy of the probable host of GRB 021211
  32. GRB 021211: Probable Host and Underlying Supernova
  33. GRB 021112: Evidence for Another Dark Optical Afterglow
  34. GRB 021219: OSN optical observations
  35. GRB021219, optical observations
  36. GRB021219, optical observation by MASTER
  37. GRB021219: a long GRB localized by INTEGRAL
  38. GRB021211: APO optical observations
  39. IPN triangulation of GRB021215 (large error box)
  40. XRF 020903 : HST observations
  41. GRB 021201: Optical Observations
  42. GRB 021211: CTIO observations
  43. GRB021211, BVRI field photometry
  44. GRB021211: Optical observations in CrAO
  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. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  53. HETE 2493: Optical observations
  54. HETE 2493: Optical candidate
  55. GRB021201, BVRcIc field photometry
  56. GRB 021201: Optical Observations
  57. GRB 021201: BOOTES simultaneous optical observations
  58. IPN triangulation of GRB021201 (short/hard burst, small error box)
  59. GRB021004, late time optical observations
  60. IPN triangulation of GRB021119 (large error box)
  61. Improved IPN error box for GRB021125
  62. GRB021125 : A long GRB localized by INTEGRAL
  63. GRB 021112: Afterglow or Variable Star?
  64. GRB021113: optical observations at Bisei
  65. GRB021112, BVRI field photometry
  66. GRB 021112: Variable Source in R-band search
  67. GRB021112: Optical Observations
  68. GRB 021113: Optical observations
  69. GRB 021112: RAPTOR Observations
  70. GRB021113 (=H2449): A Long GRB Localized by HETE
  71. GRB021112 (=H2448): A Long GRB Localized by HETE
  72. GRB 021016: Optical Observations
  73. GRB021004: Near infrared spectroscopy
  74. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  75. SGR1900+14 activity, November 2-4, 2002
  76. GRB021104: optical observations
  77. Detection of activity from SGR 1900+14 with the RXTE/PCA
  78. IPN triangulation of GRB021027 (single large error box)
  79. GRB 021004: optical observations
  80. GRB021004: Optical Observations
  81. GRB021016(=H2397): A Long GRB Localized by HETE
  82. IPN triangulation of GRB021014 (large error box)
  83. IPN triangulation of GRB021013 (two small error boxes)
  84. XRF 020903: flattening of the optical light curve.
  85. GRB021004, UBVRcIc field photometry update
  86. IPN triangulation of GRB021008 (single error box)
  87. IPN triangulation of GRB021008 (two small error boxes)
  88. GRB021004 Chandra HETG Observations
  89. GRB 021004: Optical/NIR Observations
  90. GRB 021004: Additional V-band Polarimetric Observations
  91. GRB021004: optical observation
  92. GRB 021004: Host Galaxy Star Formation Rate
  93. GRB 021004: WC wind?
  94. GRB021004: NIR and Optical observations
  95. IPN triangulation of GRB021007 (annulus)
  96. XRF 020903 spectrum
  97. GRB021004: BVRc photometry
  98. GRB 021004 redshift
  99. GRB021004 radio observation
  100. HETE fluences for GRB021004

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